bims-tucedo 2021-07-18 papers

bims-tucedo

Biomed News

on Tumor cell dormancy

Issue of 2021–07–18
twenty-one papers selected by
Isabel Puig Borreil, Vall d’Hebron Institute of Oncology

CD11b+CTLA4+ myeloid cells are a key driver of tumor evasion in colorectal cancer.
The HIF target MAFF promotes tumor invasion and metastasis through IL11 and STAT3 signaling.
Single-cell analyses reveal diverse mechanisms of resistance to EGFR tyrosine kinase inhibitors in lung cancer.
Glucocorticoid receptor triggers a reversible drug-tolerant dormancy state with acquired therapeutic vulnerabilities in lung cancer.
Cell line-specific network models of ER+ breast cancer identify potential PI3Kα inhibitor resistance mechanisms and drug combinations.
HDAC inhibitors induce LIFR expression and promote a dormancy phenotype in breast cancer.
Targeting Axl favors an antitumorigenic microenvironment that enhances immunotherapy responses by decreasing Hif-1α levels.
Tumors Induce Death in Nearby Cells to Gain Competitive Advantage.
Dexamethasone enhances the lung metastasis of breast cancer via a PI3K-SGK1-CTGF pathway.
Single cell RNA sequencing of AML initiating cells reveals RNA-based evolution during disease progression.
Repurposed floxacins targeting RSK4 prevent chemoresistance and metastasis in lung and bladder cancer.
NK cell-regulated tumour dormancy.
The newly identified MEK1 tyrosine phosphorylation target MACC1 is druggable by approved MEK1 inhibitors to restrict colorectal cancer metastasis.
Accelerating precision medicine in metastatic prostate cancer.
The GAS6-AXL signaling pathway triggers actin remodeling that drives membrane ruffling, macropinocytosis, and cancer-cell invasion.
CRIP1 cooperates with BRCA2 to drive the nuclear enrichment of RAD51 and to facilitate homologous repair upon DNA damage induced by chemotherapy.
SMARCA4 deficient tumours are vulnerable to KDM6A/UTX and KDM6B/JMJD3 blockade.
Overcoming intrinsic resistance of cancer cells to CAR T-cell killing.
Morphological screening of mesenchymal mammary tumor organoids to identify drugs that reverse epithelial-mesenchymal transition.
Disseminated tumour cells from the bone marrow of early breast cancer patients: Results from an international pooled analysis.
The Proteomic Landscape of Pancreatic Ductal Adenocarcinoma Liver Metastases Identifies Molecular Subtypes and Associations with Clinical Response-Response.

J Immunother Cancer. 2021 Jul;pii: e002841. [Epub ahead of print]9(7):

CD11b+CTLA4+ myeloid cells are a key driver of tumor evasion in colorectal cancer.

Hiroshi Imazeki, Yamato Ogiwara, Mami Kawamura, Narikazu Boku, Chie Kudo-Saito.

   BACKGROUND: Tumor metastasis is the major cause of death of colorectal cancer (CRC), and metastatic CRC remains incurable in many cases despite great advances in genetic and molecular profiling, and clinical development of numerous drugs, including immune checkpoint inhibitors. Thus, more effective treatments are urgently needed for the patients in clinical settings.
METHODS: We used mouse CRC metastasis models that murine Colon26 cells were subcutaneously and intravenously implanted and attempted to elucidate the tumor biological and immunological mechanisms underlying cancer metastasis. Then, we evaluated in vivo antitumor efficacy induced by agents targeting the identified molecular mechanisms using the mouse models. We validated the clinical relevancy of the findings using peripheral blood mononuclear cells obtained from stage IV metastatic CRC patients.
RESULTS: CD11b+CTLA4+ myeloid cells were systemically expanded in the metastatic settings and facilitated tumor progression and metastasis directly via generating lipid droplets in tumor cells and indirectly via inducing immune exhaustion. These events were mediated by IL1B produced via the CTLA4 signaling from the increased myeloid cells. Blocking CTLA4 and IL1B with the specific mAbs significantly suppressed tumor progression and metastasis in the mouse models resistant to anti-PD1 therapy, and the therapeutic efficacy was optimized by blocking cyclooxygenases with aspirin.
CONCLUSIONS: The CD11b+CTLA4+ cells are a key driver of tumor evasion, and targeting the CTLA4-IL1B axis could be a promising strategy for treating metastatic CRC. The triple combination regimen with anti-CTLA4/IL1B mAbs and aspirin may be useful in clinical settings.

Keywords:  gastrointestinal neoplasms; immune evasion; immunotherapy; myeloid-derived suppressor cells; tumor escape

DOI:  https://doi.org/10.1136/jitc-2021-002841
Nat Commun. 2021 07 14. 12(1): 4308

The HIF target MAFF promotes tumor invasion and metastasis through IL11 and STAT3 signaling.

Eui Jung Moon, Stephano S Mello, Caiyun G Li, Jen-Tsan Chi, Kaushik Thakkar, Jacob G Kirkland, Edward L Lagory, Ik Jae Lee, Anh N Diep, Yu Miao, Marjan Rafat, Marta Vilalta, Laura Castellini, Adam J Krieg, Edward E Graves, Laura D Attardi, Amato J Giaccia.

Hypoxia plays a critical role in tumor progression including invasion and metastasis. To determine critical genes regulated by hypoxia that promote invasion and metastasis, we screen fifty hypoxia inducible genes for their effects on invasion. In this study, we identify v-maf musculoaponeurotic fibrosarcoma oncogene homolog F (MAFF) as a potent regulator of tumor invasion without affecting cell viability. MAFF expression is elevated in metastatic breast cancer patients and is specifically correlated with hypoxic tumors. Combined ChIP- and RNA-sequencing identifies IL11 as a direct transcriptional target of the heterodimer between MAFF and BACH1, which leads to activation of STAT3 signaling. Inhibition of IL11 results in similar levels of metastatic suppression as inhibition of MAFF. This study demonstrates the oncogenic role of MAFF as an activator of the IL11/STAT3 pathways in breast cancer.

DOI: https://doi.org/10.1038/s41467-021-24631-6
Cancer Res. 2021 Jul 09. pii: canres.2811.2020. [Epub ahead of print]

Single-cell analyses reveal diverse mechanisms of resistance to EGFR tyrosine kinase inhibitors in lung cancer.

Yukie Kashima, Daisuke Shibahara, Ayako Suzuki, Kyoko Muto, Ikei S Kobayashi, David Plotnick, Hibiki Udagawa, Hiroki Izumi, Yuji Shibata, Kosuke Tanaka, Masanori Fujii, Akihiro Ohashi, Masahide Seki, Koichi Goto, Katsuya Tuchihara, Yutaka Suzuki, Susumu S Kobayashi.

Tumor heterogeneity underlies resistance to tyrosine kinase inhibitors (TKI) in lung cancers harboring epidermal growth factor receptor (EGFR) mutations. Previous evidence suggested that subsets of preexisting resistant cells are selected by EGFR-TKI treatment, or alternatively, that diverse acquired resistance mechanisms emerge from drug-tolerant persister (DTP) cells. Many studies have used bulk tumor specimens or subcloned resistant cell lines to identify resistance mechanism. However, intratumoral heterogeneity can result in divergent responses to therapies, requiring additional approaches to reveal the complete spectrum of resistance mechanisms. Using EGFR-TKI-resistant cell models and clinical specimens, we performed single-cell RNA-seq and single-cell ATAC-seq analyses to define the transcriptional and epigenetic landscape of parental cells, DTPs, and tumor cells in a fully resistant state. In addition to AURKA, VIM, and AXL, which are all known to induce EGFR-TKI resistance, CD74 was identified as a novel gene that plays a critical role in the drug-tolerant state. In vitro and in vivo experiments demonstrated that CD74 upregulation confers resistance to the EGFR-TKI osimertinib and blocks apoptosis, enabling tumor regrowth. Overall, this study provides new insight into the mechanisms underlying resistance to EGFR-TKIs.

DOI: https://doi.org/10.1158/0008-5472.CAN-20-2811
Nat Commun. 2021 Jul 16. 12(1): 4360

Glucocorticoid receptor triggers a reversible drug-tolerant dormancy state with acquired therapeutic vulnerabilities in lung cancer.

Stefan Prekovic, Karianne Schuurman, Isabel Mayayo-Peralta, Anna G Manjón, Mark Buijs, Selçuk Yavuz, Max D Wellenstein, Alejandro Barrera, Kim Monkhorst, Anne Huber, Ben Morris, Cor Lieftink, Theofilos Chalkiadakis, Ferhat Alkan, Joana Silva, Balázs Győrffy, Liesbeth Hoekman, Bram van den Broek, Hans Teunissen, Donna O Debets, Tesa Severson, Jos Jonkers, Timothy Reddy, Karin E de Visser, William Faller, Roderick Beijersbergen, Maarten Altelaar, Elzo de Wit, Rene Medema, Wilbert Zwart.

The glucocorticoid receptor (GR) regulates gene expression, governing aspects of homeostasis, but is also involved in cancer. Pharmacological GR activation is frequently used to alleviate therapy-related side-effects. While prior studies have shown GR activation might also have anti-proliferative action on tumours, the underpinnings of glucocorticoid action and its direct effectors in non-lymphoid solid cancers remain elusive. Here, we study the mechanisms of glucocorticoid response, focusing on lung cancer. We show that GR activation induces reversible cancer cell dormancy characterised by anticancer drug tolerance, and activation of growth factor survival signalling accompanied by vulnerability to inhibitors. GR-induced dormancy is dependent on a single GR-target gene, CDKN1C, regulated through chromatin looping of a GR-occupied upstream distal enhancer in a SWI/SNF-dependent fashion. These insights illustrate the importance of GR signalling in non-lymphoid solid cancer biology, particularly in lung cancer, and warrant caution for use of glucocorticoids in treatment of anticancer therapy related side-effects.

DOI: https://doi.org/10.1038/s41467-021-24537-3
Cancer Res. 2021 Jul 13. pii: canres.1208.2021. [Epub ahead of print]

Cell line-specific network models of ER+ breast cancer identify potential PI3Kα inhibitor resistance mechanisms and drug combinations.

Jorge Gómez Tejeda Zañudo, Pingping Mao, Clara Alcon, Kailey Kowalski, Gabriela N Johnson, Guotai Xu, Jose Baselga, Maurizio Scaltriti, Anthony Letai, Joan Montero, Réka Albert, Nikhil Wagle.

Durable control of invasive solid tumors necessitates identifying therapeutic resistance mechanisms and effective drug combinations. In this work, we used a network-based mathematical model to identify sensitivity regulators and drug combinations for the PI3Kα inhibitor alpelisib in ER+ PIK3CA mutant breast cancer. The model-predicted efficacious combination of alpelisib and BH3 mimetics, e.g., MCL1 inhibitors, was experimentally validated in ER+ breast cancer cell lines. Consistent with the model, FOXO3 downregulation reduced sensitivity to alpelisib, revealing a novel potential resistance mechanism. Cell line-specific sensitivity to combinations of alpelisib and BH3 mimetics depended on which BCL-2 family members were highly expressed. Based on these results, newly developed cell line-specific network models were able to recapitulate the observed differential response to alpelisib and BH3 mimetics. This approach illustrates how network-based mathematical models can contribute to overcoming the challenge of cancer drug resistance.

DOI: https://doi.org/10.1158/0008-5472.CAN-21-1208
Oncogene. 2021 Jul 10.

HDAC inhibitors induce LIFR expression and promote a dormancy phenotype in breast cancer.

Miranda E Clements, Lauren Holtslander, Courtney Edwards, Vera Todd, Samuel D R Dooyema, Kennady Bullock, Kensey Bergdorf, Cynthia A Zahnow, Roisin M Connolly, Rachelle W Johnson.

Despite advances in breast cancer treatment, residual disease driven by dormant tumor cells continues to be a significant clinical problem. Leukemia inhibitory factor receptor (LIFR) promotes a dormancy phenotype in breast cancer cells and LIFR loss is correlated with poor patient survival. Herein, we demonstrate that histone deacetylase inhibitors (HDACi), which are in phase III clinical trials for breast cancer, epigenetically induced LIFR and activated a pro-dormancy program in breast cancer cells. HDACi slowed breast cancer cell proliferation and reduced primary tumor growth. Primary breast tumors from HDACi-treated patients had increased LIFR levels and reduced proliferation rates compared to pre-treatment levels. Recent Phase II clinical trial data studying entinostat and azacitidine in metastatic breast cancer revealed that induction of several pro-dormancy genes post-treatment was associated with prolonged patient survival. Together, these findings suggest HDACi as a potential therapeutic avenue to promote dormancy, prevent recurrence, and improve patient outcomes in breast cancer.

DOI: https://doi.org/10.1038/s41388-021-01931-1
Proc Natl Acad Sci U S A. 2021 Jul 20. pii: e2023868118. [Epub ahead of print]118(29):

Targeting Axl favors an antitumorigenic microenvironment that enhances immunotherapy responses by decreasing Hif-1α levels.

Marie-Anne Goyette, Islam E Elkholi, Chloé Apcher, Hellen Kuasne, Carla V Rothlin, William J Muller, Darren E Richard, Morag Park, Jean-Philippe Gratton, Jean-François Côté.

  Hypoxia is an important phenomenon in solid tumors that contributes to metastasis, tumor microenvironment (TME) deregulation, and resistance to therapies. The receptor tyrosine kinase AXL is an HIF target, but its roles during hypoxic stress leading to the TME deregulation are not well defined. We report here that the mammary gland-specific deletion of Axl in a HER2+ mouse model of breast cancer leads to a normalization of the blood vessels, a proinflammatory TME, and a reduction of lung metastases by dampening the hypoxic response in tumor cells. During hypoxia, interfering with AXL reduces HIF-1α levels altering the hypoxic response leading to a reduction of hypoxia-induced epithelial-to-mesenchymal transition (EMT), invasion, and production of key cytokines for macrophages behaviors. These observations suggest that inhibition of Axl generates a suitable setting to increase immunotherapy. Accordingly, combining pharmacological inhibition of Axl with anti-PD-1 in a preclinical model of HER2+ breast cancer reduces the primary tumor and metastatic burdens, suggesting a potential therapeutic approach to manage HER2+ patients whose tumors present high hypoxic features.

Keywords:  AXL; HER2; hypoxia; immunotherapy; tumor microenvironment

DOI:  https://doi.org/10.1073/pnas.2023868118
Cancer Discov. 2021 Jul 09.

Tumors Induce Death in Nearby Cells to Gain Competitive Advantage.

Drosophila intestinal tumors disrupt adjacent healthy tissue by stimulating mechanical stress.

DOI: https://doi.org/10.1158/2159-8290.CD-RW2021-096
Oncogene. 2021 Jul 16.

Dexamethasone enhances the lung metastasis of breast cancer via a PI3K-SGK1-CTGF pathway.

Yujing Zhang, Gang Shi, Hantao Zhang, Qi Xiong, Fuyi Cheng, Huiling Wang, Jieyan Luo, Yong Zhang, Pengyi Shi, Jia Xu, Jiamei Fu, Na Chen, Lin Cheng, Yiming Li, Lei Dai, Yang Yang, Dechao Yu, Shuang Zhang, Hongxin Deng.

Dexamethasone (Dex), as a pretreatment agent, is widely used to attenuate the side effects of chemotherapy in breast cancer treatment. However, whether and how Dex affects breast cancer metastasis remain to be furtherly understood. In this study, we established several mouse breast cancer metastatic models to study the effect of Dex in vitro and in vivo. Transwell, Western Blot and RNA interference were applied to study the molecular mechanism of Dex in promoting breast cancer cell migration. Meanwhile, the effect of Dex on lung metastasis of breast cancer in Dex combined with PTX chemotherapy was discussed. Our results confirmed that Dex could promote breast cancer cell metastasis both in vitro and in vivo. Mechanistic studies revealed that this pro-metastatic effect of Dex was mediated by the GR-PI3K-SGK1-CTGF pathway in tumor cells. Ligation of Dex and glucocorticoid receptor (GR) on tumor cells activated the PI3K signaling pathway and upregulated serum glucocorticoid-inducible kinase 1 (SGK1) expression, and then increased the expression of connective tissue growth factor (CTGF) through Nedd4l-Smad2. Moreover, Dex was the leading factor for lung metastasis in a standard regimen for breast cancer treatment with paclitaxel and Dex. Importantly, targeting SGK1 with the inhibitor GSK650394 remarkably reduced lung metastasis in this regimen. Our present data provide new insights into Dex-induced breast cancer metastasis and indicate that SGK1 could be a candidate target for the treatment of breast cancer metastasis.

DOI: https://doi.org/10.1038/s41388-021-01944-w
Leukemia. 2021 Jul 09.

Single cell RNA sequencing of AML initiating cells reveals RNA-based evolution during disease progression.

L C Stetson, Dheepa Balasubramanian, Susan Pereira Ribeiro, Tammy Stefan, Kalpana Gupta, Xuan Xu, Slim Fourati, Anne Roe, Zachary Jackson, Robert Schauner, Ashish Sharma, Banumathi Tamilselvan, Samuel Li, Marcos de Lima, Tae Hyun Hwang, Robert Balderas, Yogen Saunthararajah, Jaroslaw Maciejewski, Thomas LaFramboise, Jill S Barnholtz-Sloan, Rafick-Pierre Sekaly, David N Wald.

The prognosis of most patients with AML is poor due to frequent disease relapse. The cause of relapse is thought to be from the persistence of leukemia initiating cells (LIC's) following treatment. Here we assessed RNA based changes in LICs from matched patient diagnosis and relapse samples using single-cell RNA sequencing. Previous studies on AML progression have focused on genetic changes at the DNA mutation level mostly in bulk AML cells and demonstrated the existence of DNA clonal evolution. Here we identified in LICs that the phenomenon of RNA clonal evolution occurs during AML progression. Despite the presence of vast transcriptional heterogeneity at the single cell level, pathway analysis identified common signaling networks involving metabolism, apoptosis and chemokine signaling that evolved during AML progression and become a signature of relapse samples. A subset of this gene signature was validated at the protein level in LICs by flow cytometry from an independent AML cohort and functional studies were performed to demonstrate co-targeting BCL2 and CXCR4 signaling may help overcome therapeutic challenges with AML heterogeneity. It is hoped this work will facilitate a greater understanding of AML relapse leading to improved prognostic biomarkers and therapeutic strategies to target LIC's.

DOI: https://doi.org/10.1038/s41375-021-01338-7
Sci Transl Med. 2021 Jul 14. pii: eaba4627. [Epub ahead of print]13(602):

Repurposed floxacins targeting RSK4 prevent chemoresistance and metastasis in lung and bladder cancer.

Stelios Chrysostomou, Rajat Roy, Filippo Prischi, Lucksamon Thamlikitkul, Kathryn L Chapman, Uwais Mufti, Robert Peach, Laifeng Ding, David Hancock, Christopher Moore, Miriam Molina-Arcas, Francesco Mauri, David J Pinato, Joel M Abrahams, Silvia Ottaviani, Leandro Castellano, Georgios Giamas, Jennifer Pascoe, Devmini Moonamale, Sarah Pirrie, Claire Gaunt, Lucinda Billingham, Neil M Steven, Michael Cullen, David Hrouda, Mathias Winkler, John Post, Philip Cohen, Seth J Salpeter, Vered Bar, Adi Zundelevich, Shay Golan, Dan Leibovici, Romain Lara, David R Klug, Sophia N Yaliraki, Mauricio Barahona, Yulan Wang, Julian Downward, J Mark Skehel, Maruf M U Ali, Michael J Seckl, Olivier E Pardo.

Lung and bladder cancers are mostly incurable because of the early development of drug resistance and metastatic dissemination. Hence, improved therapies that tackle these two processes are urgently needed to improve clinical outcome. We have identified RSK4 as a promoter of drug resistance and metastasis in lung and bladder cancer cells. Silencing this kinase, through either RNA interference or CRISPR, sensitized tumor cells to chemotherapy and hindered metastasis in vitro and in vivo in a tail vein injection model. Drug screening revealed several floxacin antibiotics as potent RSK4 activation inhibitors, and trovafloxacin reproduced all effects of RSK4 silencing in vitro and in/ex vivo using lung cancer xenograft and genetically engineered mouse models and bladder tumor explants. Through x-ray structure determination and Markov transient and Deuterium exchange analyses, we identified the allosteric binding site and revealed how this compound blocks RSK4 kinase activation through binding to an allosteric site and mimicking a kinase autoinhibitory mechanism involving the RSK4's hydrophobic motif. Last, we show that patients undergoing chemotherapy and adhering to prophylactic levofloxacin in the large placebo-controlled randomized phase 3 SIGNIFICANT trial had significantly increased (P = 0.048) long-term overall survival times. Hence, we suggest that RSK4 inhibition may represent an effective therapeutic strategy for treating lung and bladder cancer.

DOI: https://doi.org/10.1126/scitranslmed.aba4627
Nat Cell Biol. 2021 Jul;23(7): 677

NK cell-regulated tumour dormancy.

Zhe Wang.

DOI: https://doi.org/10.1038/s41556-021-00714-w
Oncogene. 2021 Jul 10.

The newly identified MEK1 tyrosine phosphorylation target MACC1 is druggable by approved MEK1 inhibitors to restrict colorectal cancer metastasis.

Dennis Kobelt, Daniel Perez-Hernandez, Claudia Fleuter, Mathias Dahlmann, Fabian Zincke, Janice Smith, Rebekka Migotti, Oliver Popp, Susen Burock, Wolfgang Walther, Gunnar Dittmar, Philipp Mertins, Ulrike Stein.

Cancer metastasis causes >90% of cancer deaths and remains a major treatment challenge. Here we deciphered the impact of tyrosine phosphorylation of MACC1, a causative driver for cancer metastasis, for cancer cell signaling and novel interventions to restrict cancer metastasis. We identified MACC1 as new MEK1 substrate. MEK1 directly phosphorylates MACC1, leading to accelerated and increased ERK1 activation. Mutating in silico predicted hierarchical MACC1 tyrosine phosphorylation sites abrogates MACC1-induced migration, invasion, and MET expression, a transcriptional MACC1 target. Targeting MEK1 by RNAi or clinically applicable MEK1 inhibitors AZD6244 and GSK1120212 reduces MACC1 tyrosine phosphorylation and restricts MACC1-induced metastasis formation in mice. Although MEK1 levels, contrary to MACC1, are not of prognostic relevance for CRC patients, MEK1 expression was found indispensable for MACC1-induced metastasis. This study identifies MACC1 as new MEK1 substrate for tyrosine phosphorylation decisively impacting cell motility, tumor growth, and metastasis. Thus, MAP kinase signaling is not linear leading to ERK activation, but branches at the level of MEK1. This fundamental finding opens new therapeutic options for targeting the MEK1/MACC1 axis as novel vulnerability in patients at high risk for metastasis. This might be extended from CRC to further solid tumor entities.

DOI: https://doi.org/10.1038/s41388-021-01917-z
Nat Cancer. 2020 Nov;1(11): 1041-1053

Accelerating precision medicine in metastatic prostate cancer.

Joaquin Mateo, Rana McKay, Wassim Abida, Rahul Aggarwal, Joshi Alumkal, Ajjai Alva, Felix Feng, Xin Gao, Julie Graff, Maha Hussain, Fatima Karzai, Bruce Montgomery, William Oh, Vaibhav Patel, Dana Rathkopf, Matthew Rettig, Nikolaus Schultz, Matthew Smith, David Solit, Cora Sternberg, Eliezer Van Allen, David VanderWeele, Jake Vinson, Howard R Soule, Arul Chinnaiyan, Eric Small, Jonathan W Simons, William Dahut, Andrea K Miyahira, Himisha Beltran.

Despite advances in prostate cancer screening and treatment, available therapy options, particularly in later stages of the disease, remain limited and the treatment-resistant setting represents a serious unmet medical need. Moreover, disease heterogeneity and disparities in patient access to medical advances result in significant variability in outcomes across patients. Disease classification based on genomic sequencing is a promising approach to identify patients whose tumors exhibit actionable targets and make more informed treatment decisions. Here we discuss how we can accelerate precision oncology to inform broader genomically-driven clinical decisions for men with advanced prostate cancer, drug development and ultimately contribute to new treatment paradigms.

DOI: https://doi.org/10.1038/s43018-020-00141-0
Proc Natl Acad Sci U S A. 2021 Jul 13. pii: e2024596118. [Epub ahead of print]118(28):

The GAS6-AXL signaling pathway triggers actin remodeling that drives membrane ruffling, macropinocytosis, and cancer-cell invasion.

Daria Zdżalik-Bielecka, Agata Poświata, Kamila Kozik, Kamil Jastrzębski, Kay Oliver Schink, Marta Brewińska-Olchowik, Katarzyna Piwocka, Harald Stenmark, Marta Miączyńska.

  AXL, a member of the TAM (TYRO3, AXL, MER) receptor tyrosine kinase family, and its ligand, GAS6, are implicated in oncogenesis and metastasis of many cancer types. However, the exact cellular processes activated by GAS6-AXL remain largely unexplored. Here, we identified an interactome of AXL and revealed its associations with proteins regulating actin dynamics. Consistently, GAS6-mediated AXL activation triggered actin remodeling manifested by peripheral membrane ruffling and circular dorsal ruffles (CDRs). This further promoted macropinocytosis that mediated the internalization of GAS6-AXL complexes and sustained survival of glioblastoma cells grown under glutamine-deprived conditions. GAS6-induced CDRs contributed to focal adhesion turnover, cell spreading, and elongation. Consequently, AXL activation by GAS6 drove invasion of cancer cells in a spheroid model. All these processes required the kinase activity of AXL, but not TYRO3, and downstream activation of PI3K and RAC1. We propose that GAS6-AXL signaling induces multiple actin-driven cytoskeletal rearrangements that contribute to cancer-cell invasion.

Keywords:  GAS6-AXL; TAM receptors; actin; macropinocytosis; membrane ruffles

DOI:  https://doi.org/10.1073/pnas.2024596118
Oncogene. 2021 Jul 14.

CRIP1 cooperates with BRCA2 to drive the nuclear enrichment of RAD51 and to facilitate homologous repair upon DNA damage induced by chemotherapy.

Huiying Sun, Rui Zhou, Yannan Zheng, Zhaowei Wen, Dingling Zhang, Dongqiang Zeng, Jianhua Wu, Zhenhua Huang, Xiaoxiang Rong, Na Huang, Li Sun, Jianping Bin, Yulin Liao, Min Shi, Wangjun Liao.

Homologous recombination (HR) repair is an important determinant of chemosensitivity. However, the mechanisms underlying HR regulation remain largely unknown. Cysteine-rich intestinal protein 1 (CRIP1) is a member of the LIM/double-zinc finger protein family and is overexpressed and associated with prognosis in several tumor types. However, to date, the functional role of CRIP1 in cancer biology is poorly understood. Here we found that CRIP1 downregulation causes HR repair deficiency with concomitant increase in cell sensitivity to cisplatin, epirubicin, and the poly ADP-ribose polymerase (PARP) inhibitor olaparib in gastric cancer cells. Mechanistically, upon DNA damage, CRIP1 is deubiquitinated and upregulated by activated AKT signaling. CRIP1, in turn, promotes nuclear enrichment of RAD51, which is a prerequisite step for HR commencement, by stabilizing BRCA2 to counteract FBXO5-targeted RAD51 degradation and by binding to the core domain of RAD51 (RAD51184-257) in coordination with BRCA2, to facilitate nuclear export signal masking interactions between BRCA2 and RAD51. Moreover, through mass spectrometry screening, we found that KPNA4 is at least one of the carriers controlling the nucleo-cytoplasmic distribution of the CRIP1-BRCA2-RAD51 complex in response to chemotherapy. Consistent with these findings, RAD51 inhibitors block the CRIP1-mediated HR process, thereby restoring chemotherapy sensitivity of gastric cancer cells with high CRIP1 expression. Analysis of patient specimens revealed an abnormally high level of CRIP1 expression in GC tissues compared to that in the adjacent normal mucosa and a significant negative association between CRIP1 expression and survival time in patient cohorts with different types of solid tumors undergoing genotoxic treatments. In conclusion, our study suggests an essential function of CRIP1 in promoting HR repair and facilitating gastric cancer cell adaptation to genotoxic therapy.

DOI: https://doi.org/10.1038/s41388-021-01932-0
Nat Commun. 2021 07 14. 12(1): 4319

SMARCA4 deficient tumours are vulnerable to KDM6A/UTX and KDM6B/JMJD3 blockade.

Octavio A Romero, Andrea Vilarrubi, Juan J Alburquerque-Bejar, Antonio Gomez, Alvaro Andrades, Deborah Trastulli, Eva Pros, Fernando Setien, Sara Verdura, Lourdes Farré, Juan F Martín-Tejera, Paula Llabata, Ana Oaknin, Maria Saigi, Josep M Piulats, Xavier Matias-Guiu, Pedro P Medina, August Vidal, Alberto Villanueva, Montse Sanchez-Cespedes.

Despite the genetic inactivation of SMARCA4, a core component of the SWI/SNF-complex commonly found in cancer, there are no therapies that effectively target SMARCA4-deficient tumours. Here, we show that, unlike the cells with activated MYC oncogene, cells with SMARCA4 inactivation are refractory to the histone deacetylase inhibitor, SAHA, leading to the aberrant accumulation of H3K27me3. SMARCA4-mutant cells also show an impaired transactivation and significantly reduced levels of the histone demethylases KDM6A/UTX and KDM6B/JMJD3, and a strong dependency on these histone demethylases, so that its inhibition compromises cell viability. Administering the KDM6 inhibitor GSK-J4 to mice orthotopically implanted with SMARCA4-mutant lung cancer cells or primary small cell carcinoma of the ovary, hypercalcaemic type (SCCOHT), had strong anti-tumour effects. In this work we highlight the vulnerability of KDM6 inhibitors as a characteristic that could be exploited for treating SMARCA4-mutant cancer patients.

DOI: https://doi.org/10.1038/s41467-021-24618-3
Clin Cancer Res. 2021 Jul 12. pii: clincanres.1559.2021. [Epub ahead of print]

Overcoming intrinsic resistance of cancer cells to CAR T-cell killing.

Jean Lemoine, Marco Ruella, Roch Houot.

In the past few years, chimeric antigen receptor (CAR) T-cell therapy has emerged as a promising treatment for cancers that failed standard treatments. Such therapies have already been approved in several blood cancers such as B-cell leukemia and lymphoma. Despite this progress, a significant proportion of patients experience primary or secondary resistance to CAR-T cell therapy. Here, we review the mechanisms by which CAR T-cells eliminate their target and how cancer cells may be insensitive to such killing (here referred to as intrinsic resistance). Recent studies suggest that the activation of apoptosis through death receptor signaling is responsible for a major part of CAR T-cell cytotoxicity in vivo. Indeed, cancer cells harboring aberrant apoptotic machinery may be insensitive to CAR T-cell killing. This intrinsic resistance of cancer cells to CAR T-cell killing could be responsible for a significant portion of treatment failure. Lastly, we discuss strategies that may be envisioned to overcome such resistance in order to enhance CAR T-cell efficacy.

DOI: https://doi.org/10.1158/1078-0432.CCR-21-1559
Nat Commun. 2021 07 12. 12(1): 4262

Morphological screening of mesenchymal mammary tumor organoids to identify drugs that reverse epithelial-mesenchymal transition.

Na Zhao, Reid T Powell, Xueying Yuan, Goeun Bae, Kevin P Roarty, Fabio Stossi, Martina Strempfl, Michael J Toneff, Hannah L Johnson, Sendurai A Mani, Philip Jones, Clifford C Stephan, Jeffrey M Rosen.

The epithelial-mesenchymal transition (EMT) has been implicated in conferring stem cell properties and therapeutic resistance to cancer cells. Therefore, identification of drugs that can reprogram EMT may provide new therapeutic strategies. Here, we report that cells derived from claudin-low mammary tumors, a mesenchymal subtype of triple-negative breast cancer, exhibit a distinctive organoid structure with extended "spikes" in 3D matrices. Upon a miR-200 induced mesenchymal-epithelial transition (MET), the organoids switch to a smoother round morphology. Based on these observations, we developed a morphological screening method with accompanying analytical pipelines that leverage deep neural networks and nearest neighborhood classification to screen for EMT-reversing drugs. Through screening of a targeted epigenetic drug library, we identified multiple class I HDAC inhibitors and Bromodomain inhibitors that reverse EMT. These data support the use of morphological screening of mesenchymal mammary tumor organoids as a platform to identify drugs that reverse EMT.

DOI: https://doi.org/10.1038/s41467-021-24545-3
Eur J Cancer. 2021 Jul 12. pii: S0959-8049(21)00403-2. [Epub ahead of print]154 128-137

Disseminated tumour cells from the bone marrow of early breast cancer patients: Results from an international pooled analysis.

Andreas D Hartkopf, Sara Y Brucker, Florin-Andrei Taran, Nadia Harbeck, Alexandra von Au, Bjørn Naume, Jean-Yves Pierga, Oliver Hoffmann, Matthias W Beckmann, Lisa Rydén, Tanja Fehm, Rebecca Aft, Montserrat Solà, Vincent Walter, Brigitte Rack, Florian Schuetz, Elin Borgen, Minh-Hanh Ta, Ann-Kathrin Bittner, Peter A Fasching, Mårten Fernö, Natalia Krawczyk, Katherine Weilbaecher, Mireia Margelí, Markus Hahn, Julia Jueckstock, Christoph Domschke, Francois-Clement Bidard, Sabine Kasimir-Bauer, Birgitt Schoenfisch, Ayse G Kurt, Markus Wallwiener, Gerhard Gebauer, Christoph A Klein, Diethelm Wallwiener, Wolfgang Janni, Klaus Pantel.

   PURPOSE: Presence of disseminated tumour cells (DTCs) in the bone marrow (BM) has been described as a surrogate of residual disease in patients with early breast cancer (EBC). PADDY (Pooled Analysis of DTC Detection in Early Breast Cancer) is a large international analysis of pooled data that aimed to assess the prognostic impact of DTCs in patients with EBC.
EXPERIMENTAL DESIGN: Individual patient data were collected from 11 centres. Patients with EBC and available follow-up data in whom BM sampling was performed at the time of primary diagnosis before receiving any anticancer treatment were eligible. DTCs were identified by antibody staining against epithelial cytokeratins. Multivariate Cox regression was used to compare the survival of DTC-positive versus DTC-negative patients.
RESULTS: In total, 10,307 patients were included. Of these, 2814 (27.3%) were DTC-positive. DTC detection was associated with higher tumour grade, larger tumour size, nodal positivity, oestrogen receptor and progesterone receptor negativity, and HER2 positivity (all p < 0.001). Multivariate analyses showed that DTC detection was an independent prognostic marker for overall survival, disease-free survival and distant disease-free survival with hazard ratios (HR) and 95% confidence intervals (CI) of 1.23 (95% CI: 1.06-1.43, p = 0.006), 1.30 (95% CI: 1.12-1.52, p < 0.001) and 1.30 (95% CI: 1.08-1.56, p = 0.006), respectively. There was no association between locoregional relapse-free survival and DTC detection (HR 1.21; 95% CI 0.68-2.16; p = 0.512).
CONCLUSIONS: DTCs in the BM represent an independent prognostic marker in patients with EBC. The heterogeneous metastasis-initiating potential of DTCs is consistent with the concept of cancer dormancy.

Keywords:  Bone marrow; Disseminated tumour cells; Early breast cancer; Micrometastases; Prognosis; Tumour staging

DOI:  https://doi.org/10.1016/j.ejca.2021.06.028
Clin Cancer Res. 2021 Jul 15. 27(14): 4127

The Proteomic Landscape of Pancreatic Ductal Adenocarcinoma Liver Metastases Identifies Molecular Subtypes and Associations with Clinical Response-Response.

Henry C-H Law, Emalie J Clement, Paul M Grandgenett, Michael A Hollingsworth, Nicholas T Woods.

DOI: https://doi.org/10.1158/1078-0432.CCR-21-1220