bims-tucedo 2022-08-07 papers

bims-tucedo

Biomed News

on Tumor cell dormancy

Issue of 2022–08–07
28 papers selected by
Isabel Puig Borreil, Vall d’Hebron Institute of Oncology

Serine metabolism remodeling after platinum-based chemotherapy identifies vulnerabilities in a subgroup of resistant ovarian cancers.
Lung fibroblasts facilitate pre-metastatic niche formation by remodeling the local immune microenvironment.
Metabolic reprogramming from glycolysis to fatty acid uptake and beta-oxidation in platinum-resistant cancer cells.
Identification of a molecularly-defined subset of breast and ovarian cancer models that respond to WEE1 or ATR inhibition, overcoming PARP inhibitor resistance.
CircIPO7 Promotes Nasopharyngeal Carcinoma Metastasis and Cisplatin Chemoresistance by Facilitating YBX1 Nuclear Localization.
Raman spectroscopy reveals phenotype switches in breast cancer metastasis.
FOXA1 inhibits hypoxia programs through transcriptional repression of HIF1A.
Triple-negative breast cancer metastasis involves complex epithelial-mesenchymal transition dynamics and requires vimentin.
Emerging metabolomic tools to study cancer metastasis.
AP-1 transcription factor network explains diverse patterns of cellular plasticity in melanoma cells.
Structure-guided and phage-assisted evolution of a therapeutic anti-EGFR antibody to reverse acquired resistance.
Specific KRAS-Mutant Cancers Are Sensitive to Inhibition of V-type ATPases.
Glioblastoma hijacks neuronal mechanisms for brain invasion.
Inhibition of CDK8/19 Mediator kinase potentiates HER2-targeting drugs and bypasses resistance to these agents in vitro and in vivo.
Targeting KRAS mutant cancers: from druggable therapy to drug resistance.
DCLK1 promotes colorectal cancer stemness and aggressiveness via the XRCC5/COX2 axis.
Tumor-polarized GPX3+ AT2 lung epithelial cells promote premetastatic niche formation.
METTL3 preferentially enhances non-m6A translation of epigenetic factors and promotes tumourigenesis.
Inflammation: the incubator of the tumor microenvironment.
EGFR ligand shifts the role of EGFR from oncogene to tumour suppressor in EGFR-amplified glioblastoma by suppressing invasion through BIN3 upregulation.
Nucleotide imbalance decouples cell growth from cell proliferation.
Inhibition of LSD1 with bomedemstat sensitizes small cell lung cancer to immune checkpoint blockade and T cell killing.
HER2-targeted dual radiotracer approach with clinical potential for noninvasive imaging of trastuzumab-resistance caused by epitope masking.
Dynamic and adaptive cancer stem cell population admixture in colorectal neoplasia.
Phenotypic heterogeneity driven by plasticity of the intermediate EMT state governs disease progression and metastasis in breast cancer.
Hypoxia-induced proteasomal degradation of DBC1 by SIAH2 in breast cancer progression.
Cancer cell states recur across tumor types and form specific interactions with the tumor microenvironment.
Microbial metabolite restricts 5-fluorouracil-resistant colonic tumor progression by sensitizing drug transporters via regulation of FOXO3-FOXM1 axis.

Nat Commun. 2022 Aug 05. 13(1): 4578

Serine metabolism remodeling after platinum-based chemotherapy identifies vulnerabilities in a subgroup of resistant ovarian cancers.

Tom Van Nyen, Mélanie Planque, Lilian van Wagensveld, Joao A G Duarte, Esther A Zaal, Ali Talebi, Matteo Rossi, Pierre-René Körner, Lara Rizzotto, Stijn Moens, Wout De Wispelaere, Regina E M Baiden-Amissah, Gabe S Sonke, Hugo M Horlings, Guy Eelen, Emanuele Berardi, Johannes V Swinnen, Celia R Berkers, Peter Carmeliet, Diether Lambrechts, Ben Davidson, Reuven Agami, Sarah-Maria Fendt, Daniela Annibali, Frédéric Amant.

Resistance to platinum-based chemotherapy represents a major clinical challenge for many tumors, including epithelial ovarian cancer. Patients often experience several response-relapse events, until tumors become resistant and life expectancy drops to 12-15 months. Despite improved knowledge of the molecular determinants of platinum resistance, the lack of clinical applicability limits exploitation of many potential targets, leaving patients with limited options. Serine biosynthesis has been linked to cancer growth and poor prognosis in various cancer types, however its role in platinum-resistant ovarian cancer is not known. Here, we show that a subgroup of resistant tumors decreases phosphoglycerate dehydrogenase (PHGDH) expression at relapse after platinum-based chemotherapy. Mechanistically, we observe that this phenomenon is accompanied by a specific oxidized nicotinamide adenine dinucleotide (NAD+) regenerating phenotype, which helps tumor cells in sustaining Poly (ADP-ribose) polymerase (PARP) activity under platinum treatment. Our findings reveal metabolic vulnerabilities with clinical implications for a subset of platinum resistant ovarian cancers.

DOI: https://doi.org/10.1038/s41467-022-32272-6
Immunity. 2022 Jul 30. pii: S1074-7613(22)00334-X. [Epub ahead of print]

Lung fibroblasts facilitate pre-metastatic niche formation by remodeling the local immune microenvironment.

Zheng Gong, Qing Li, Jiayuan Shi, Jian Wei, Peishan Li, Chih-Hao Chang, Leonard D Shultz, Guangwen Ren.

  Primary tumors are drivers of pre-metastatic niche formation, but the coordination by the secondary organ toward metastatic dissemination is underappreciated. Here, by single-cell RNA sequencing and immunofluorescence, we identified a population of cyclooxygenase 2 (COX-2)-expressing adventitial fibroblasts that remodeled the lung immune microenvironment. At steady state, fibroblasts in the lungs produced prostaglandin E2 (PGE2), which drove dysfunctional dendritic cells (DCs) and suppressive monocytes. This lung-intrinsic stromal program was propagated by tumor-associated inflammation, particularly the pro-inflammatory cytokine interleukin-1β, supporting a pre-metastatic niche. Genetic ablation of Ptgs2 (encoding COX-2) in fibroblasts was sufficient to reverse the immune-suppressive phenotypes of lung-resident myeloid cells, resulting in heightened immune activation and diminished lung metastasis in multiple breast cancer models. Moreover, the anti-metastatic activity of DC-based therapy and PD-1 blockade was improved by fibroblast-specific Ptgs2 deletion or dual inhibition of PGE2 receptors EP2 and EP4. Collectively, lung-resident fibroblasts reshape the local immune landscape to facilitate breast cancer metastasis.

Keywords:  PGE2; breast cancer; dendritic cells; fibroblasts; immune dysfunction; immunosuppression; immunotherapeutics; lung metastasis; monocytes; pre-metastatic niche

DOI:  https://doi.org/10.1016/j.immuni.2022.07.001
Nat Commun. 2022 Aug 05. 13(1): 4554

Metabolic reprogramming from glycolysis to fatty acid uptake and beta-oxidation in platinum-resistant cancer cells.

Yuying Tan, Junjie Li, Guangyuan Zhao, Kai-Chih Huang, Horacio Cardenas, Yinu Wang, Daniela Matei, Ji-Xin Cheng.

Increased glycolysis is considered as a hallmark of cancer. Yet, cancer cell metabolic reprograming during therapeutic resistance development is under-studied. Here, through high-throughput stimulated Raman scattering imaging and single cell analysis, we find that cisplatin-resistant cells exhibit increased fatty acids (FA) uptake, accompanied by decreased glucose uptake and lipogenesis, indicating reprogramming from glucose to FA dependent anabolic and energy metabolism. A metabolic index incorporating glucose derived anabolism and FA uptake correlates linearly to the level of cisplatin resistance in ovarian cancer (OC) cell lines and primary cells. The increased FA uptake facilitates cancer cell survival under cisplatin-induced oxidative stress by enhancing beta-oxidation. Consequently, blocking beta-oxidation by a small molecule inhibitor combined with cisplatin or carboplatin synergistically suppresses OC proliferation in vitro and growth of patient-derived xenografts in vivo. Collectively, these findings support a rapid detection method of cisplatin-resistance at single cell level and a strategy for treating cisplatin-resistant tumors.

DOI: https://doi.org/10.1038/s41467-022-32101-w
Clin Cancer Res. 2022 Aug 03. pii: CCR-22-0568. [Epub ahead of print]

Identification of a molecularly-defined subset of breast and ovarian cancer models that respond to WEE1 or ATR inhibition, overcoming PARP inhibitor resistance.

Violeta Serra, Anderson T Wang, Marta Castroviejo-Bermejo, Urszula M Polanska, Marta Palafox, Andrea Herencia-Ropero, Gemma N Jones, Zhongwu Lai, Joshua Armenia, Filippos Michopoulos, Alba Llop-Guevara, Rachel Brough, Aditi Gulati, Stephen J Pettitt, Krishna C Bulusu, Jenni Nikkilä, Zena Wilson, Adina M Hughes, Paul W G Wijnhoven, Ambar Ahmed, Alejandra Bruna, Albert Gris-Oliver, Marta Guzman, Olga Rodriguez, Judit Grueso, Joaquín Arribas, Javier Cortés, Cristina Saura, Alan Lau, Susan E Critchlow, Brian Dougherty, Carlos Caldas, Gordon B Mills, J Carl Barrett, Josep V Forment, Elaine B Cadogan, Christopher J Lord, Cristina Cruz, Judith Balmaña, Mark J O'Connor.

PURPOSE: PARP inhibitors (PARPi) induce synthetic lethality in homologous recombination repair (HRR) deficient tumors and are used to treat breast, ovarian, pancreatic and prostate cancers. Multiple PARPi resistance mechanisms exist, most resulting in restoration of HRR and protection of stalled replication forks. ATR inhibition was highlighted as a unique approach to reverse both aspects of resistance. Recently, however, a PARPi/WEE1 inhibitor combination demonstrated enhanced anti-tumor activity associated with the induction of replication stress, suggesting another approach to tackling PARPi resistance.
EXPERIMENTAL DESIGN: We analyzed breast and ovarian patient-derived xenoimplant (PDX) models resistant to PARPi to quantify WEE1i and ATRi responses as single agents and in combination with PARPi. Biomarker analysis was conducted at the genetic and protein level. Metabolite analysis by mass spectrometry and nucleoside rescue experiments ex vivo were also conducted in patient-derived models.
RESULTS: While WEE1i response was linked to markers of replication stress, including STK11/RB1 and phospho-RPA, ATRi response associated with ATM mutation. When combined with olaparib, WEE1i could be differentiated from the ATRi/olaparib combination, providing distinct therapeutic strategies to overcome PARPi resistance by targeting the replication stress response. Mechanistically, WEE1i sensitivity was associated with shortage of the dNTP pool and a concomitant increase in replication stress.
CONCLUSION: Targeting the replication stress response is a valid therapeutic option to overcome PARPi resistance including tumors without an underlying HRR deficiency. These preclinical insights are now being tested in several clinical trials where the PARPi is administered with either the WEE1i or the ATRi.

DOI: https://doi.org/10.1158/1078-0432.CCR-22-0568
Clin Cancer Res. 2022 Aug 02. pii: CCR-22-0991. [Epub ahead of print]

CircIPO7 Promotes Nasopharyngeal Carcinoma Metastasis and Cisplatin Chemoresistance by Facilitating YBX1 Nuclear Localization.

Xiaohong Hong, Qian Li, Junyan Li, Kailin Chen, Qingmei He, Yuheng Zhao, Yelin Liang, Yin Zhao, Han Qiao, Na Liu, Jun Ma, Yingqin Li.

PURPOSE: Cisplatin-based chemotherapy effectively improves the distant-metastasis control in nasopharyngeal carcinoma (NPC), but approximately 30% of patients develop treatment failure due to chemoresistance. However, the underlying mechanisms remain poorly understood.
EXPERIMENTAL DESIGN: CircRNA sequencing data were used to identify metastasis-specific circRNAs and the expression of circIPO7 was validated in NPC tissues as well as NPC cell lines by qRT-PCR. The whole transcriptional profile upon circIPO7 knockdown was applied to explore the biological function and regulatory mechanism, which were further confirmed by in vitro and in vivo metastasis/chemosensitivity assays. We also evaluated the value of circIPO7 expression in predicting NPC metastasis and cisplatin chemoresistance by analyzing a cohort of 183 NPC patients.
RESULTS: In the current study, circIPO7, a novel circular RNA (circRNA), is found to be specifically overexpressed in NPC patients with distant metastasis. Knockdown of circIPO7 in NPC cells suppresses their metastasis and increases sensitivity to cisplatin treatment in vitro and in vivo. Mechanistically, circIPO7 binds to Y-box binding protein-1 (YBX1) protein in the cytoplasm and facilitates its phosphorylation at serine 102 (p-YBX1S102) by the kinase AKT, which further promotes YBX1 nuclear translocation and activates FGFR1, TNC, and NTRK1 transcription. Clinically, higher circIPO7 expression indicates unfavorable distant metastasis-free survival in NPC patients given cisplatin-based chemotherapy.
CONCLUSIONS: Altogether, this study identifies oncogenic circIPO7 as a prognostic marker after cisplatin-based chemotherapy and as a potential therapeutic target for overcoming metastasis and chemoresistance in NPC.

DOI: https://doi.org/10.1158/1078-0432.CCR-22-0991
Theranostics. 2022 ;12(12): 5351-5363

Raman spectroscopy reveals phenotype switches in breast cancer metastasis.

Santosh Kumar Paidi, Joel Rodriguez Troncoso, Mason G Harper, Zhenhui Liu, Khue G Nguyen, Sruthi Ravindranathan, Lisa Rebello, David E Lee, Jesse D Ivers, David A Zaharoff, Narasimhan Rajaram, Ishan Barman.

  The accurate analytical characterization of metastatic phenotype at primary tumor diagnosis and its evolution with time are critical for controlling metastatic progression of cancer. Here, we report a label-free optical strategy using Raman spectroscopy and machine learning to identify distinct metastatic phenotypes observed in tumors formed by isogenic murine breast cancer cell lines of progressively increasing metastatic propensities. Methods: We employed the 4T1 isogenic panel of murine breast cancer cells to grow tumors of varying metastatic potential and acquired label-free spectra using a fiber probe-based portable Raman spectroscopy system. We used MCR-ALS and random forests classifiers to identify putative spectral markers and predict metastatic phenotype of tumors based on their optical spectra. We also used tumors derived from 4T1 cells silenced for the expression of TWIST, FOXC2 and CXCR3 genes to assess their metastatic phenotype based on their Raman spectra. Results: The MCR-ALS spectral decomposition showed consistent differences in the contribution of components that resembled collagen and lipids between the non-metastatic 67NR tumors and the metastatic tumors formed by FARN, 4T07, and 4T1 cells. Our Raman spectra-based random forest analysis provided evidence that machine learning models built on spectral data can allow the accurate identification of metastatic phenotype of independent test tumors. By silencing genes critical for metastasis in highly metastatic cell lines, we showed that the random forest classifiers provided predictions consistent with the observed phenotypic switch of the resultant tumors towards lower metastatic potential. Furthermore, the spectral assessment of lipid and collagen content of these tumors was consistent with the observed phenotypic switch. Conclusion: Overall, our findings indicate that Raman spectroscopy may offer a novel strategy to evaluate metastatic risk during primary tumor biopsies in clinical patients.

Keywords:  Cancer metastasis; Phenotype switch; Raman spectroscopy; Random forests; TWIST

DOI:  https://doi.org/10.7150/thno.74002
Oncogene. 2022 Aug 05.

FOXA1 inhibits hypoxia programs through transcriptional repression of HIF1A.

Xiaohai Wang, Lourdes Brea, Xiaodong Lu, Galina Gritsina, Su H Park, Wanqing Xie, Jonathan C Zhao, Jindan Yu.

Intratumoral hypoxia is associated with castration-resistant prostate cancer (CRPC), a lethal disease. FOXA1 is an epithelial transcription factor that is down-regulated in CRPC. We have previously reported that FOXA1 loss induces epithelial-mesenchymal transition (EMT) and cell motility through elevated TGFβ signaling. However, whether FOXA1 directly regulates hypoxia pathways of CRPC tumors has not been previously studied. Here we report that FOXA1 down-regulation induces hypoxia transcriptional programs, and FOXA1 level is negatively correlated with hypoxia markers in clinical prostate cancer (PCa) samples. Mechanistically, FOXA1 directly binds to an intragenic enhancer of HIF1A to inhibit its expression, and HIF1A, in turn, is critical in mediating FOXA1 loss-induced hypoxia gene expression. Further, we identify CCL2, a chemokine ligand that modulates tumor microenvironment and promotes cancer progression, as a crucial target of the FOXA1-HIF1A axis. We found that FOXA1 loss leads to immunosuppressive macrophage infiltration and increased cell invasion, dependent on HIF1A expression. Critically, therapeutic targeting of HIF1A-CCL2 using pharmacological inhibitors abolishes FOXA1 loss-induced macrophage infiltration and PCa cell invasion. In summary, our study reveals an essential role of FOXA1 in controlling the hypoxic tumor microenvironment and establishes the HIF1A-CCL2 axis as one mechanism of FOXA1 loss-induced CRPC progression.

DOI: https://doi.org/10.1038/s41388-022-02423-6
Sci Transl Med. 2022 Aug 03. 14(656): eabn7571

Triple-negative breast cancer metastasis involves complex epithelial-mesenchymal transition dynamics and requires vimentin.

Eloïse M Grasset, Matthew Dunworth, Gaurav Sharma, Melanie Loth, Joseph Tandurella, Ashley Cimino-Mathews, Melissa Gentz, Sydney Bracht, Meagan Haynes, Elana J Fertig, Andrew J Ewald.

Triple-negative breast cancer (TNBC) is an aggressive subtype associated with early metastatic recurrence and worse patient outcomes. TNBC tumors express molecular markers of the epithelial-mesenchymal transition (EMT), but its requirement during spontaneous TNBC metastasis in vivo remains incompletely understood. We demonstrated that spontaneous TNBC tumors from a genetically engineered mouse model (GEMM), multiple patient-derived xenografts, and archival patient samples exhibited large populations in vivo of hybrid E/M cells that lead invasion ex vivo while expressing both epithelial and mesenchymal characteristics. The mesenchymal marker vimentin promoted invasion and repressed metastatic outgrowth. We next tested the requirement for five EMT transcription factors and observed distinct patterns of utilization during invasion and colony formation. These differences suggested a sequential activation of multiple EMT molecular programs during the metastatic cascade. Consistent with this model, our longitudinal single-cell RNA analysis detected three different EMT-related molecular patterns. We observed cancer cells progressing from epithelial to hybrid E/M and strongly mesenchymal patterns during invasion and from epithelial to a hybrid E/M pattern during colony formation. We next investigated the relative epithelial versus mesenchymal state of cancer cells in both GEMM and patient metastases. In both contexts, we observed heterogeneity between and within metastases in the same individual. We observed a complex spectrum of epithelial, hybrid E/M, and mesenchymal cell states within metastases, suggesting that there are multiple successful molecular strategies for distant organ colonization. Together, our results demonstrate an important and complex role for EMT programs during TNBC metastasis.

DOI: https://doi.org/10.1126/scitranslmed.abn7571
Trends Cancer. 2022 Jul 28. pii: S2405-8033(22)00156-X. [Epub ahead of print]

Emerging metabolomic tools to study cancer metastasis.

Luiza Martins Nascentes Melo, Nicholas P Lesner, Marie Sabatier, Jessalyn M Ubellacker, Alpaslan Tasdogan.

  Metastasis is responsible for 90% of deaths in patients with cancer. Understanding the role of metabolism during metastasis has been limited by the development of robust and sensitive technologies that capture metabolic processes in metastasizing cancer cells. We discuss the current technologies available to study (i) metabolism in primary and metastatic cancer cells and (ii) metabolic interactions between cancer cells and the tumor microenvironment (TME) at different stages of the metastatic cascade. We identify advantages and disadvantages of each method and discuss how these tools and technologies will further improve our understanding of metastasis. Studies investigating the complex metabolic rewiring of different cells using state-of-the-art metabolomic technologies have the potential to reveal novel biological processes and therapeutic interventions for human cancers.

Keywords:  analytical techniques; cancer metabolism; cancer metastasis; metabolomics

DOI:  https://doi.org/10.1016/j.trecan.2022.07.003
Cell Rep. 2022 Aug 02. pii: S2211-1247(22)00956-1. [Epub ahead of print]40(5): 111147

AP-1 transcription factor network explains diverse patterns of cellular plasticity in melanoma cells.

Natacha Comandante-Lou, Douglas G Baumann, Mohammad Fallahi-Sichani.

  Cellular plasticity associated with fluctuations in transcriptional programs allows individual cells in a tumor to adopt heterogeneous differentiation states and switch phenotype during their adaptive responses to therapies. Despite increasing knowledge of such transcriptional programs, the molecular basis of cellular plasticity remains poorly understood. Here, we combine multiplexed transcriptional and protein measurements at population and single-cell levels with multivariate statistical modeling to show that the state of AP-1 transcription factor network plays a unifying role in explaining diverse patterns of plasticity in melanoma. We find that a regulated balance among AP-1 factors cJUN, JUND, FRA2, FRA1, and cFOS determines the intrinsic diversity of differentiation states and adaptive responses to MAPK inhibitors in melanoma cells. Perturbing this balance through genetic depletion of specific AP-1 proteins, or by MAPK inhibitors, shifts cellular heterogeneity in a predictable fashion. Thus, AP-1 may serve as a critical node for manipulating cellular plasticity with potential therapeutic implications.

Keywords:  AP-1 transcription factors; BRAF-mutant melanoma; CP: Cancer; CP: Molecular biology; MAPK signaling pathway; adaptive drug resistance; cellular plasticity; computational modeling; differentiation state heterogeneity; single-cell analysis; statistical learning; targeted therapies

DOI:  https://doi.org/10.1016/j.celrep.2022.111147
Nat Commun. 2022 Jul 30. 13(1): 4431

Structure-guided and phage-assisted evolution of a therapeutic anti-EGFR antibody to reverse acquired resistance.

Xinlei Zhuang, Zhe Wang, Jiansheng Fan, Xuefei Bai, Yingchun Xu, James J Chou, Tingjun Hou, Shuqing Chen, Liqiang Pan.

Acquired resistance to cetuximab in colorectal cancers is partially mediated by the acquisition of mutations located in the cetuximab epitope in the epidermal growth factor receptor (EGFR) ectodomain and hinders the clinical application of cetuximab. We develop a structure-guided and phage-assisted evolution approach for cetuximab evolution to reverse EGFRS492R- or EGFRG465R-driven resistance without altering the binding epitope or undermining antibody efficacy. Two evolved cetuximab variants, Ctx-VY and Ctx-Y104D, exhibit a restored binding ability with EGFRS492R, which harbors the most common resistance substitution, S492R. Ctx-W52D exhibits restored binding with EGFR harboring another common cetuximab resistance substitution, G465R (EGFRG465R). All the evolved cetuximab variants effectively inhibit EGFR activation and downstream signaling and induce the internalization and degradation of EGFRS492R and EGFRG465R as well as EGFRWT. The evolved cetuximab variants (Ctx-VY, Ctx-Y104D and Ctx-W52D) with one or two amino acid substitutions in the complementarity-determining region inherit the optimized physical and chemical properties of cetuximab to a great extent, thus ensuring their druggability. Our data collectively show that structure-guided and phage-assisted evolution is an efficient and general approach for reversing receptor mutation-mediated resistance to therapeutic antibody drugs.

DOI: https://doi.org/10.1038/s41467-022-32159-6
Cancer Discov. 2022 Aug 05. OF1

Specific KRAS-Mutant Cancers Are Sensitive to Inhibition of V-type ATPases.

249C was identified as a selective Ras-mutant cytotoxic agent that binds to and inhibits V-ATPase.

DOI: https://doi.org/10.1158/2159-8290.CD-RW2022-142
Cell. 2022 Aug 04. pii: S0092-8674(22)00847-9. [Epub ahead of print]185(16): 2899-2917.e31

Glioblastoma hijacks neuronal mechanisms for brain invasion.

Varun Venkataramani, Yvonne Yang, Marc Cicero Schubert, Ekin Reyhan, Svenja Kristin Tetzlaff, Niklas Wißmann, Michael Botz, Stella Judith Soyka, Carlo Antonio Beretta, Rangel Lyubomirov Pramatarov, Laura Fankhauser, Luciano Garofano, Alexander Freudenberg, Julia Wagner, Dimitar Ivanov Tanev, Miriam Ratliff, Ruifan Xie, Tobias Kessler, Dirk C Hoffmann, Ling Hai, Yvette Dörflinger, Simone Hoppe, Yahaya A Yabo, Anna Golebiewska, Simone P Niclou, Felix Sahm, Anna Lasorella, Martin Slowik, Leif Döring, Antonio Iavarone, Wolfgang Wick, Thomas Kuner, Frank Winkler.

  Glioblastomas are incurable tumors infiltrating the brain. A subpopulation of glioblastoma cells forms a functional and therapy-resistant tumor cell network interconnected by tumor microtubes (TMs). Other subpopulations appear unconnected, and their biological role remains unclear. Here, we demonstrate that whole-brain colonization is fueled by glioblastoma cells that lack connections with other tumor cells and astrocytes yet receive synaptic input from neurons. This subpopulation corresponds to neuronal and neural-progenitor-like tumor cell states, as defined by single-cell transcriptomics, both in mouse models and in the human disease. Tumor cell invasion resembled neuronal migration mechanisms and adopted a Lévy-like movement pattern of probing the environment. Neuronal activity induced complex calcium signals in glioblastoma cells followed by the de novo formation of TMs and increased invasion speed. Collectively, superimposing molecular and functional single-cell data revealed that neuronal mechanisms govern glioblastoma cell invasion on multiple levels. This explains how glioblastoma's dissemination and cellular heterogeneity are closely interlinked.

Keywords:  cancer neuroscience; cell heterogeneity; glioblastoma; glutamatergic synapse; neurogliomal synapses; neuron-tumor interaction; tumor cell networks; tumor microtubes

DOI:  https://doi.org/10.1016/j.cell.2022.06.054
Proc Natl Acad Sci U S A. 2022 Aug 09. 119(32): e2201073119

Inhibition of CDK8/19 Mediator kinase potentiates HER2-targeting drugs and bypasses resistance to these agents in vitro and in vivo.

Xiaokai Ding, Amanda C Sharko, Martina S J McDermott, Gary P Schools, Alexander Chumanevich, Hao Ji, Jing Li, Li Zhang, Zachary T Mack, Vitali Sikirzhytski, Michael Shtutman, Laura Ivers, Norma O'Donovan, John Crown, Balázs Győrffy, Mengqian Chen, Igor B Roninson, Eugenia V Broude.

  Breast cancers (BrCas) that overexpress oncogenic tyrosine kinase receptor HER2 are treated with HER2-targeting antibodies (such as trastuzumab) or small-molecule kinase inhibitors (such as lapatinib). However, most patients with metastatic HER2+ BrCa have intrinsic resistance and nearly all eventually become resistant to HER2-targeting therapy. Resistance to HER2-targeting drugs frequently involves transcriptional reprogramming associated with constitutive activation of different signaling pathways. We have investigated the role of CDK8/19 Mediator kinase, a regulator of transcriptional reprogramming, in the response of HER2+ BrCa to HER2-targeting drugs. CDK8 was in the top 1% of all genes ranked by correlation with shorter relapse-free survival among treated HER2+ BrCa patients. Selective CDK8/19 inhibitors (senexin B and SNX631) showed synergistic interactions with lapatinib and trastuzumab in a panel of HER2+ BrCa cell lines, overcoming and preventing resistance to HER2-targeting drugs. The synergistic effects were mediated in part through the PI3K/AKT/mTOR pathway and reduced by PI3K inhibition. Combination of HER2- and CDK8/19-targeting agents inhibited STAT1 and STAT3 phosphorylation at S727 and up-regulated tumor suppressor BTG2. The growth of xenograft tumors formed by lapatinib-sensitive or -resistant HER2+ breast cancer cells was partially inhibited by SNX631 alone and strongly suppressed by the combination of SNX631 and lapatinib, overcoming lapatinib resistance. These effects were associated with decreased tumor cell proliferation and altered recruitment of stromal components to the xenograft tumors. These results suggest potential clinical benefit of combining HER2- and CDK8/19-targeting drugs in the treatment of metastatic HER2+ BrCa.

Keywords:  CDK8/19; HER2; Mediator kinase; lapatinib; trastuzumab

DOI:  https://doi.org/10.1073/pnas.2201073119
Mol Cancer. 2022 Aug 04. 21(1): 159

Targeting KRAS mutant cancers: from druggable therapy to drug resistance.

Chunxiao Zhu, Xiaoqing Guan, Xinuo Zhang, Xin Luan, Zhengbo Song, Xiangdong Cheng, Weidong Zhang, Jiang-Jiang Qin.

  Kirsten Rat Sarcoma Viral Oncogene Homolog (KRAS) is the most frequently mutated oncogene, occurring in a variety of tumor types. Targeting KRAS mutations with drugs is challenging because KRAS is considered undruggable due to the lack of classic drug binding sites. Over the past 40 years, great efforts have been made to explore routes for indirect targeting of KRAS mutant cancers, including KRAS expression, processing, upstream regulators, or downstream effectors. With the advent of KRAS (G12C) inhibitors, KRAS mutations are now druggable. Despite such inhibitors showing remarkable clinical responses, resistance to monotherapy of KRAS inhibitors is eventually developed. Significant progress has been made in understanding the mechanisms of drug resistance to KRAS-mutant inhibitors. Here we review the most recent advances in therapeutic approaches and resistance mechanisms targeting KRAS mutations and discuss opportunities for combination therapy.

Keywords:  Combination therapy; Druggable; KRAS mutations; Resistance

DOI:  https://doi.org/10.1186/s12943-022-01629-2
Theranostics. 2022 ;12(12): 5258-5271

DCLK1 promotes colorectal cancer stemness and aggressiveness via the XRCC5/COX2 axis.

Jee-Heun Kim, So-Yeon Park, So-El Jeon, Jang-Hyun Choi, Choong-Jae Lee, Tae-Young Jang, Hyeon-Ji Yun, Yuno Lee, Pilho Kim, Sang Hee Cho, Ji Shin Lee, Jeong-Seok Nam.

  Rationale: Doublecortin-like kinase 1 (DCLK1) is a serine/threonine kinase that selectively marks cancer stem-like cells (CSCs) and promotes malignant progression in colorectal cancer (CRC). However, the exact molecular mechanism by which DCLK1 drives the aggressive phenotype of cancer cells is incompletely determined. Methods: Here, we performed comprehensive genomics and proteomics analyses to identify binding proteins of DCLK1 and discovered X-ray repair cross-complementing 5 (XRCC5). Thus, we explored the biological role and downstream events of the DCLK1/XRCC5 axis in human CRC cells and CRC mouse models. Results: The results of comprehensive bioinformatics analyses suggested that DCLK1-driven CRC aggressiveness is linked to inflammation. Mechanistically, DCLK1 bound and phosphorylated XRCC5, which in turn transcriptionally activated cyclooxygenase-2 expression and enhanced prostaglandin E2 production; these events collectively generated the inflammatory tumor microenvironment and enhanced the aggressive behavior of CRC cells. Consistent with the discovered mechanism, inhibition of DCLK1 kinase activity strongly impaired the tumor seeding and growth capabilities in CRC mouse models. Conclusion: Our study illuminates a novel mechanism that mediates the pro-inflammatory function of CSCs in driving the aggressive phenotype of CRC, broadening the biological function of DCLK1 in CRC.

Keywords:  Cancer stem cells; Doublecortin-like kinase 1; Inflammatory tumor microenvironment; Prostaglandin E2

DOI:  https://doi.org/10.7150/thno.72037
Proc Natl Acad Sci U S A. 2022 Aug 09. 119(32): e2201899119

Tumor-polarized GPX3+ AT2 lung epithelial cells promote premetastatic niche formation.

Zixin Wang, Jie Zhu, Yanfang Liu, Ziqiao Wang, Xuetao Cao, Yan Gu.

  The cellular and molecular components required for the formation of premetastatic niche (PMN) to promote lung metastasis need to be further investigated. Lung epithelial cells have been reported to exhibit immunomodulatory roles in lung homeostasis and also to mediate immunosuppressive PMN formation in lung metastasis. Here, by single-cell sequencing, we identified a tumor-polarized subpopulation of alveolar type 2 (AT2) epithelial cells with increased expression of glutathione peroxidase 3 (GPX3) and high production of interleukin (IL)-10 in the PMN. IL-10-producing GPX3+ AT2 cells inhibited CD4+ T cell proliferation but enhanced regulatory T cell generation. Mechanistically, tumor exosome-inducing GPX3 expression is required for GPX3+ AT2 cells to preferentially produce IL-10 by stabilizing hypoxia-inducible factor 1 (HIF-1α) and promoting HIF-1α-induced IL-10 production. Accordingly, conditional knockout of GPX3 in AT2 cells suppressed lung metastasis in spontaneous metastatic models. Together, our findings reveal a role of tumor-polarized GPX3+ AT2 cells in promoting lung PMN formation, adding insights into immune evasion in lung metastasis and providing potential targets for the intervention of tumor metastasis.

Keywords:  alveolar type 2 epithelial cells; glutathione peroxidase 3; interleukin-10; lung metastasis; premetastatic niche

DOI:  https://doi.org/10.1073/pnas.2201899119
Nat Cell Biol. 2022 Aug 04.

METTL3 preferentially enhances non-m6A translation of epigenetic factors and promotes tumourigenesis.

Xueju Wei, Yue Huo, Jingnan Pi, Yufeng Gao, Shuan Rao, Manman He, Qinglv Wei, Peng Song, Yiying Chen, Dongxu Lu, Wei Song, Junbo Liang, Lingjie Xu, Haixia Wang, Guolin Hong, Yuehong Guo, Yanmin Si, Jiayue Xu, Xiaoshuang Wang, Yanni Ma, Shuyang Yu, Dongling Zou, Jing Jin, Fang Wang, Jia Yu.

METTL3 encodes the predominant catalytic enzyme to promote m6A methylation in nucleus. Recently, accumulating evidence has shown the expression of METTL3 in cytoplasm, but its function is not fully understood. Here we demonstrated an m6A-independent mechanism for METTL3 to promote tumour progression. In gastric cancer, METTL3 could not only facilitate cancer progression via m6A modification, but also bind to numerous non-m6A-modified mRNAs, suggesting an unexpected role of METTL3. Mechanistically, cytoplasm-anchored METTL3 interacted with PABPC1 to stabilize its association with cap-binding complex eIF4F, which preferentially promoted the translation of epigenetic factors without m6A modification. Clinical investigation showed that cytoplasmic distributed METTL3 was highly correlated with gastric cancer progression, and this finding could be expanded to prostate cancer. Therefore, the cytoplasmic METTL3 enhances the translation of epigenetic mRNAs, thus serving as an oncogenic driver in cancer progression, and METTL3 subcellular distribution can assist diagnosis and predict prognosis for patients with cancer.

DOI: https://doi.org/10.1038/s41556-022-00968-y
Trends Cancer. 2022 Jul 27. pii: S2405-8033(22)00154-6. [Epub ahead of print]

Inflammation: the incubator of the tumor microenvironment.

Dominic Denk, Florian R Greten.

  An inflammatory microenvironment, either conferred by an underlying chronic overt or smoldering inflammatory condition constitutes a prerequisite and fuel to essentially all cancers. The complex reciprocal interplay of different cell types in the tumor microenvironment (TME) determines patient outcome. Apart from the actual tumor cells, local and recruited nonmalignant cells as well as the intestinal microbiome actively shape polarization and plasticity of cells in the TME, thereby augmenting protumorigenic and prometastatic inflammatory processes. Here, we address the universality of inflammation in carcinogenesis, review distinct forms of tumor related inflammation and highlight critical processes in the TME actively sustaining a nurturing incubator for cancer progression and therapy resistance.

Keywords:  immune response; inflammation; tumor microenvironment

DOI:  https://doi.org/10.1016/j.trecan.2022.07.002
Nat Cell Biol. 2022 Aug 01.

EGFR ligand shifts the role of EGFR from oncogene to tumour suppressor in EGFR-amplified glioblastoma by suppressing invasion through BIN3 upregulation.

Gao Guo, Ke Gong, Nicole Beckley, Yue Zhang, Xiaoyao Yang, Rati Chkheidze, Kimmo J Hatanpaa, Tomas Garzon-Muvdi, Prasad Koduru, Arifa Nayab, Jennifer Jenks, Adwait Amod Sathe, Yan Liu, Chao Xing, Shwu-Yuan Wu, Cheng-Ming Chiang, Bipasha Mukherjee, Sandeep Burma, Bryan Wohlfeld, Toral Patel, Bruce Mickey, Kalil Abdullah, Michael Youssef, Edward Pan, David E Gerber, Shulan Tian, Jann N Sarkaria, Samuel K McBrayer, Dawen Zhao, Amyn A Habib.

The epidermal growth factor receptor (EGFR) is a prime oncogene that is frequently amplified in glioblastomas. Here we demonstrate a new tumour-suppressive function of EGFR in EGFR-amplified glioblastomas regulated by EGFR ligands. Constitutive EGFR signalling promotes invasion via activation of a TAB1-TAK1-NF-κB-EMP1 pathway, resulting in large tumours and decreased survival in orthotopic models. Ligand-activated EGFR promotes proliferation and surprisingly suppresses invasion by upregulating BIN3, which inhibits a DOCK7-regulated Rho GTPase pathway, resulting in small hyperproliferating non-invasive tumours and improved survival. Data from The Cancer Genome Atlas reveal that in EGFR-amplified glioblastomas, a low level of EGFR ligands confers a worse prognosis, whereas a high level of EGFR ligands confers an improved prognosis. Thus, increased EGFR ligand levels shift the role of EGFR from oncogene to tumour suppressor in EGFR-amplified glioblastomas by suppressing invasion. The tumour-suppressive function of EGFR can be activated therapeutically using tofacitinib, which suppresses invasion by increasing EGFR ligand levels and upregulating BIN3.

DOI: https://doi.org/10.1038/s41556-022-00962-4
Nat Cell Biol. 2022 Aug 04.

Nucleotide imbalance decouples cell growth from cell proliferation.

Frances F Diehl, Teemu P Miettinen, Ryan Elbashir, Christopher S Nabel, Alicia M Darnell, Brian T Do, Scott R Manalis, Caroline A Lewis, Matthew G Vander Heiden.

Nucleotide metabolism supports RNA synthesis and DNA replication to enable cell growth and division. Nucleotide depletion can inhibit cell growth and proliferation, but how cells sense and respond to changes in the relative levels of individual nucleotides is unclear. Moreover, the nucleotide requirement for biomass production changes over the course of the cell cycle, and how cells coordinate differential nucleotide demands with cell cycle progression is not well understood. Here we find that excess levels of individual nucleotides can inhibit proliferation by disrupting the relative levels of nucleotide bases needed for DNA replication and impeding DNA replication. The resulting purine and pyrimidine imbalances are not sensed by canonical growth regulatory pathways like mTORC1, Akt and AMPK signalling cascades, causing excessive cell growth despite inhibited proliferation. Instead, cells rely on replication stress signalling to survive during, and recover from, nucleotide imbalance during S phase. We find that ATR-dependent replication stress signalling is activated during unperturbed S phases and promotes nucleotide availability to support DNA replication. Together, these data reveal that imbalanced nucleotide levels are not detected until S phase, rendering cells reliant on replication stress signalling to cope with this metabolic problem and disrupting the coordination of cell growth and division.

DOI: https://doi.org/10.1038/s41556-022-00965-1
Clin Cancer Res. 2022 Aug 03. pii: CCR-22-1128. [Epub ahead of print]

Inhibition of LSD1 with bomedemstat sensitizes small cell lung cancer to immune checkpoint blockade and T cell killing.

Joseph B Hiatt, Holly Sandborg, Sarah M Garrison, Henry U Arnold, Sheng-You Liao, Justin P Norton, Travis J Friesen, Feinan Wu, Kate D Sutherland, Hugh Y Rienhoff, Renato Martins, A McGarry Houghton, Shivani Srivastava, David MacPherson.

PURPOSE: The addition of immune checkpoint blockade (ICB) to platinum/etoposide chemotherapy changed the standard of care for small cell lung cancer (SCLC) treatment. However, ICB addition only modestly improved clinical outcomes, likely reflecting the high prevalence of an immunologically "cold" tumor microenvironment in SCLC, despite high mutational burden. Nevertheless, some patients clearly benefit from ICB and recent reports have associated clinical responses to ICB in SCLC with A) decreased neuroendocrine characteristics and B) activation of NOTCH signaling. We previously showed that inhibition of the LSD1 demethylase activates NOTCH and suppresses neuroendocrine features of SCLC, leading us to investigate whether LSD1 inhibition would enhance the response to PD1 inhibition in SCLC.
EXPERIMENTAL DESIGN: We employed a syngeneic immunocompetent model of SCLC, derived from a genetically engineered mouse model harboring Rb1/Trp53 inactivation, to investigate combining the LSD1 inhibitor bomedemstat with anti-PD1 therapy. In vivo experiments were complemented by cell-based studies in murine and human models.
RESULTS: Bomedemstat potentiated responses to PD1 inhibition in a syngeneic model of SCLC, resulting in increased CD8+ T cell infiltration and strong tumor growth inhibition. Bomedemstat increased MHC class I expression in mouse SCLC tumor cells in vivo and augmented MHC-I induction by interferon-ɣ and increased killing by tumor specific T cells in cell culture.
CONCLUSIONS: LSD1 inhibition increased MHC-I expression and enhanced responses to PD1 inhibition in vivo, supporting a new clinical trial to combine bomedemstat with standard of care PD1 axis inhibition in SCLC.

DOI: https://doi.org/10.1158/1078-0432.CCR-22-1128
Theranostics. 2022 ;12(12): 5551-5563

HER2-targeted dual radiotracer approach with clinical potential for noninvasive imaging of trastuzumab-resistance caused by epitope masking.

Liqiang Li, Tianyu Liu, Linqing Shi, Xin Zhang, Xiaoyi Guo, Biao Hu, Meinan Yao, Hua Zhu, Zhi Yang, Bing Jia, Fan Wang.

  Rationale: The decreased HER2-accessibility by epitope masking is a primary trastuzumab-resistance mechanism. In this study, we developed a HER2-targeted dual radiotracer approach to predict the HER2-trastuzumab engagement noninvasively. Methods: Two novel HER2-specific VHHs, MIRC208 and MIRC213, were acquired by immunizing alpaca with human HER2 protein, and were site-specifically labeled with 99mTc. Biodistribution and SPECT/CT imaging studies were performed in mice bearing HER2-positive and HER2-negative tumors. The HER2 binding sites of 99mTc-MIRC208 and 99mTc-MIRC213 were investigated by cell binding and SPECT/CT imaging studies. We evaluated the therapeutic predictive ability of our dual-radiotracer imaging approach for trastuzumab treatment in mice bearing MUC4-positive tumors (trastuzumab-resistant JIMT-1 and 87MUC4) and MUC4-negative tumors (trastuzumab-sensitive 7HER2 and NCI-N87). The preliminary clinical studies of 99mTc-MIRC208 were performed in two patients with HER2-positive breast tumors. Results: 99mTc-MIRC208 and 99mTc-MIRC213 clearly visualized HER2-positive tumors, but not HER2-negative tumors. 99mTc-MIRC208 competes with trastuzumab for HER2-binding while 99mTc-MIRC213 recognizes HER2 on an epitope that is not masked by MUC4. The SPECT/CT studies with 99mTc-MIRC208 and 99mTc-MIRC213 clearly showed that the MUC4-negative and trastuzumab-sensitive 7HER2 and NCI-N87 tumors had very similar tumor uptake with the SUV208/SUV213 (2 h) ratios of 1.11 ± 0.17 in 7HER2 and 1.25 ± 0.22 in NCI-N87. However, the MUC4-positive JIMT-1 tumors showed the decreased SUV208/SUV213 (2 h) ratio (0.63 ± 0.07), which correlated well with the low response rate to trastuzumab therapy. The SUV208/SUV213 (2 h) ratio was reduced to 0.72 ± 0.02 in MUC4-expressing NCI-N87 cells, and resulting in the decreased trastuzumab sensitivity, further supporting the correlation between the SUV208/SUV213 (2 h) ratio and trastuzumab-sensitivity. The primary and metastatic HER2-positive lesions of patients were clearly visualized by 99mTc-MIRC208 SPECT at 2 h post injection. Conclusion: Overall, we demonstrated that the dual radiotracer imaging strategy is a valid noninvasive approach for the cancer patient selection before trastuzumab therapy. 99mTc-MIRC213 SPECT is utilized to quantify the tumor HER2 expression and screen HER2-positive cancer patients, while 99mTc-MIRC208 SPECT is used to determine the HER2-accessibility of trastuzumab. The SUV208/SUV213 (2 h) ratio is an important biomarker to determine the responsiveness of trastuzumab therapy.

Keywords:  HER2-targeted therapy; SPECT/CT imaging; Trastuzumab; VHH

DOI:  https://doi.org/10.7150/thno.74154
Cell Stem Cell. 2022 Aug 04. pii: S1934-5909(22)00303-4. [Epub ahead of print]29(8): 1213-1228.e8

Dynamic and adaptive cancer stem cell population admixture in colorectal neoplasia.

Ester Gil Vasquez, Nadia Nasreddin, Gabriel N Valbuena, Eoghan J Mulholland, Hayley L Belnoue-Davis, Holly R Eggington, Ryan O Schenck, Valérie M Wouters, Pratyaksha Wirapati, Kathryn Gilroy, Tamsin R M Lannagan, Dustin J Flanagan, Arafath K Najumudeen, Sulochana Omwenga, Amy M B McCorry, Alistair Easton, Viktor H Koelzer, James E East, Dion Morton, Livio Trusolino, Timothy Maughan, Andrew D Campbell, Maurice B Loughrey, Philip D Dunne, Petros Tsantoulis, David J Huels, Sabine Tejpar, Owen J Sansom, Simon J Leedham.

  Intestinal homeostasis is underpinned by LGR5+ve crypt-base columnar stem cells (CBCs), but following injury, dedifferentiation results in the emergence of LGR5-ve regenerative stem cell populations (RSCs), characterized by fetal transcriptional profiles. Neoplasia hijacks regenerative signaling, so we assessed the distribution of CBCs and RSCs in mouse and human intestinal tumors. Using combined molecular-morphological analysis, we demonstrate variable expression of stem cell markers across a range of lesions. The degree of CBC-RSC admixture was associated with both epithelial mutation and microenvironmental signaling disruption and could be mapped across disease molecular subtypes. The CBC-RSC equilibrium was adaptive, with a dynamic response to acute selective pressure, and adaptability was associated with chemoresistance. We propose a fitness landscape model where individual tumors have equilibrated stem cell population distributions along a CBC-RSC phenotypic axis. Cellular plasticity is represented by position shift along this axis and is influenced by cell-intrinsic, extrinsic, and therapeutic selective pressures.

Keywords:  cell plasticity; colorectal cancer; colorectal neoplasia; intestinal polyps; intestinal stem cells; molecular phenotyping; stem cells

DOI:  https://doi.org/10.1016/j.stem.2022.07.008
Sci Adv. 2022 Aug 05. 8(31): eabj8002

Phenotypic heterogeneity driven by plasticity of the intermediate EMT state governs disease progression and metastasis in breast cancer.

Meredith S Brown, Behnaz Abdollahi, Owen M Wilkins, Hanxu Lu, Priyanka Chakraborty, Nevena B Ognjenovic, Kristen E Muller, Mohit Kumar Jolly, Brock C Christensen, Saeed Hassanpour, Diwakar R Pattabiraman.

The epithelial-to-mesenchymal transition (EMT) is frequently co-opted by cancer cells to enhance migratory and invasive cell traits. It is a key contributor to heterogeneity, chemoresistance, and metastasis in many carcinoma types, where the intermediate EMT state plays a critical tumor-initiating role. We isolate multiple distinct single-cell clones from the SUM149PT human breast cell line spanning the EMT spectrum having diverse migratory, tumor-initiating, and metastatic qualities, including three unique intermediates. Using a multiomics approach, we identify CBFβ as a key regulator of metastatic ability in the intermediate state. To quantify epithelial-mesenchymal heterogeneity within tumors, we develop an advanced multiplexed immunostaining approach using SUM149-derived orthotopic tumors and find that the EMT state and epithelial-mesenchymal heterogeneity are predictive of overall survival in a cohort of stage III breast cancer. Our model reveals previously unidentified insights into the complex EMT spectrum and its regulatory networks, as well as the contributions of epithelial-mesenchymal plasticity (EMP) in tumor heterogeneity in breast cancer.

DOI: https://doi.org/10.1126/sciadv.abj8002
Elife. 2022 Aug 01. pii: e81247. [Epub ahead of print]11

Hypoxia-induced proteasomal degradation of DBC1 by SIAH2 in breast cancer progression.

Qiangqiang Liu, Qian Luo, Jianyu Feng, Yanping Zhao, Biao Ma, Hongcheng Cheng, Tian Zhao, Hong Lei, Chenglong Mu, Linbo Chen, Yuanyuan Meng, Jiaojiao Zhang, Yijia Long, Jingyi Su, Guo Chen, Yanjun Li, Gang Hu, Xudong Liao, Quan Chen, Yushan Zhu.

  DBC1 has been characterized as a key regulator of physiological and pathophysiological activities, such as DNA damage, senescence and tumorigenesis. However, the mechanism by which the functional stability of DBC1 is regulated has yet to be elucidated. Here, we report that the ubiquitination-mediated degradation of DBC1 is regulated by the E3 ubiquitin ligase SIAH2 and deubiquitinase OTUD5 under hypoxic stress. Mechanistically, hypoxia promoted DBC1 to interact with SIAH2 but not OTUD5, resulting in the ubiquitination and subsequent degradation of DBC1 through the ubiquitin-proteasome pathway. SIAH2 knockout inhibited tumor cell proliferation and migration, which could be rescued by double knockout of SIAH2/CCAR2. Human tissue microarray analysis further revealed that the SIAH2/DBC1 axis was responsible for tumor progression under hypoxic stress. These findings define a key role of the hypoxia-mediated SIAH2-DBC1 pathway in the progression of human breast cancer and provide novel insights into the metastatic mechanism of breast cancer.

Keywords:  cancer biology; cell biology; mouse

DOI:  https://doi.org/10.7554/eLife.81247
Nat Genet. 2022 Aug;54(8): 1192-1201

Cancer cell states recur across tumor types and form specific interactions with the tumor microenvironment.

Dalia Barkley, Reuben Moncada, Maayan Pour, Deborah A Liberman, Ian Dryg, Gregor Werba, Wei Wang, Maayan Baron, Anjali Rao, Bo Xia, Gustavo S França, Alejandro Weil, Deborah F Delair, Cristina Hajdu, Amanda W Lund, Iman Osman, Itai Yanai.

Transcriptional heterogeneity among malignant cells of a tumor has been studied in individual cancer types and shown to be organized into cancer cell states; however, it remains unclear to what extent these states span tumor types, constituting general features of cancer. Here, we perform a pan-cancer single-cell RNA-sequencing analysis across 15 cancer types and identify a catalog of gene modules whose expression defines recurrent cancer cell states including 'stress', 'interferon response', 'epithelial-mesenchymal transition', 'metal response', 'basal' and 'ciliated'. Spatial transcriptomic analysis linked the interferon response in cancer cells to T cells and macrophages in the tumor microenvironment. Using mouse models, we further found that induction of the interferon response module varies by tumor location and is diminished upon elimination of lymphocytes. Our work provides a framework for studying how cancer cell states interact with the tumor microenvironment to form organized systems capable of immune evasion, drug resistance and metastasis.

DOI: https://doi.org/10.1038/s41588-022-01141-9
Theranostics. 2022 ;12(12): 5574-5595

Microbial metabolite restricts 5-fluorouracil-resistant colonic tumor progression by sensitizing drug transporters via regulation of FOXO3-FOXM1 axis.

Sweta Ghosh, Rajbir Singh, Zachary Matthew Vanwinkle, Haixun Guo, Praveen Kumar Vemula, Ajay Goel, Bodduluri Haribabu, Venkatakrishna Rao Jala.

  The survival rate of colorectal cancer patients is adversely affected by the selection of tumors resistant to conventional anti-cancer drugs such as 5-fluorouracil (5FU). Although there is mounting evidence that commensal gut microbiota is essential for effective colon cancer treatment, the detailed molecular mechanisms and the role of gut microbial metabolites remain elusive. The goal of this study is to decipher the impact and mechanisms of gut microbial metabolite, urolithin A (UroA) and its structural analogue, UAS03 on reversal of 5FU-resistant (5FUR) colon cancers. Methods: We have utilized the SW480 and HCT-116 parental (5FU-sensitive) and 5FUR colon cancer cells to examine the chemosensitization effects of UroA or UAS03 by using both in vitro and in vivo models. The effects of mono (UroA/UAS03/5FU) and combinatorial therapy (UroA/UAS03 + 5FU) on cell proliferation, apoptosis, cell migration and invasion, regulation of epithelial mesenchymal transition (EMT) mediators, expression and activities of drug transporters, and their regulatory transcription factors were examined using molecular, cellular, immunological and flowcytometric methods. Further, the anti-tumor effects of mono/combination therapy (UroA or UAS03 or 5FU or UroA/UAS03 + 5FU) were examined using pre-clinical models of 5FUR-tumor xenografts in NRGS mice and azoxymethane (AOM)-dextran sodium sulfate (DSS)-induced colon tumors. Results: Our data showed that UroA or UAS03 in combination with 5FU significantly inhibited cell viability, proliferation, invasiveness as well as induced apoptosis of the 5FUR colon cancer cells compared to mono treatments. Mechanistically, UroA or UAS03 chemosensitized the 5FUR cancer cells by downregulating the expression and activities of drug transporters (MDR1, BCRP, MRP2 and MRP7) leading to a decrease in the efflux of 5FU. Further, our data suggested the UroA or UAS03 chemosensitized 5FUR cancer cells to 5FU treatment through regulating FOXO3-FOXM1 axis. Oral treatment with UroA or UAS03 in combination with low dose i.p. 5FU significantly reduced the growth of 5FUR-tumor xenografts in NRGS mice. Further, combination therapy significantly abrogated colonic tumors in AOM-DSS-induced colon tumors in mice. Conclusions: In summary, gut microbial metabolite UroA and its structural analogue UAS03 chemosensitized the 5FUR colon cancers for effective 5FU chemotherapy. This study provided the novel characteristics of gut microbial metabolites to have significant translational implications in drug-resistant cancer therapeutics.

Keywords:  5-Fluorouracil; Chemoresistant colon cancer; Chemosensitization; FOXO3-FOXM1 axis; Microbial metabolite; Urolithin A; drug transporters

DOI:  https://doi.org/10.7150/thno.70754