bims-tucedo Biomed News
on Tumor cell dormancy
Issue of 2020‒08‒02
thirty-one papers selected by
Isabel Puig Borreil
Vall d’Hebron Institute of Oncology


  1. Clin Cancer Res. 2020 Jul 28. pii: clincanres.3958.2019. [Epub ahead of print]
    Mao P, Cohen O, Kowalski KJ, Kusiel J, Buendia-Buendia JE, Cuoco MS, Exman P, Wander SA, Waks AG, Nayar U, Chung JH, Freeman SS, Rozenblatt-Rosen O, Miller VA, Piccioni F, Root DE, Regev A, Winer EP, Lin NU, Wagle N.
      PURPOSE: To identify clinically relevant mechanisms of resistance to ER-directed therapies in ER+ breast cancer.EXPERIMENTAL DESIGN: We conducted a genome-scale functional screen spanning 10,135 genes to investigate genes whose overexpression confer resistance to selective estrogen receptor degraders. In parallel, we performed whole exome sequencing in paired pre-treatment and post-resistance biopsies from 60 patients with ER+ metastatic breast cancer who had developed resistance to ER-targeted therapy. Furthermore, we performed experiments to validate resistance genes/pathways and to identify drug combinations to overcome resistance.
    RESULTS: Pathway analysis of candidate resistance genes demonstrated that the FGFR, ERBB, insulin receptor, and MAPK pathways represented key modalities of resistance. The FGFR pathway was altered via FGFR1, FGFR2, or FGF3 amplifications or FGFR2 mutations in 24 (40%) of the post-resistance biopsies. In 12 of the 24 post-resistance tumors exhibiting FGFR/FGF alterations, these alterations were acquired or enriched under the selective pressure of ER-directed therapy. In vitro experiments in ER+ breast cancer cells confirmed that FGFR/FGF alterations led to fulvestrant resistance as well as cross-resistance to the CDK4/6 inhibitor palbociclib. RNA sequencing of resistant cell lines demonstrated that FGFR/FGF induced resistance through ER reprogramming and activation of the MAPK pathway. The resistance phenotypes were reversed by FGFR inhibitors, a MEK inhibitor, and/or a SHP2 inhibitor.
    CONCLUSIONS: Our results suggest that FGFR pathway is a distinct mechanism of acquired resistance to ER-directed therapy that can be overcome by FGFR and/or MAPK pathway inhibitors.
    DOI:  https://doi.org/10.1158/1078-0432.CCR-19-3958
  2. Cancer Res. 2020 Jul 23. pii: canres.1184.2019. [Epub ahead of print]
    Dattilo R, Mottini C, Camera E, Lamolinara A, Auslander N, Doglioni G, Muscolini M, Tang W, Planque M, Ercolani C, Buglioni S, Manni I, Trisciuoglio D, Boe A, Grande S, Luciani AM, Iezzi M, Ciliberto G, Ambs S, De Maria R, Fendt SM, Ruppin E, Cardone L.
      Cancer stem-like cells (CSC) induce aggressive tumor phenotypes such as metastasis formation, which is associated with poor prognosis in triple-negative breast cancer (TNBC). Repurposing of FDA-approved drugs that can eradicate the CSC subcompartment in primary tumors may prevent metastatic disease, thus representing an effective strategy to improve the prognosis of TNBC. Here we investigated spheroid-forming cells in a metastatic TNBC model. This strategy enabled us to specifically study a population of long-lived tumor cells enriched in CSC, which show stem-like characteristics and induce metastases. To repurpose FDA-approved drugs potentially toxic for CSC, we focused on pyrvinium pamoate (PP), an anthelmintic drug with documented anti-cancer activity in preclinical models. PP induced cytotoxic effects in CSC and prevented metastasis formation. Mechanistically, the cell killing effects of PP were a result of inhibition of lipid anabolism and, more specifically, the impairment of anabolic flux from glucose to cholesterol and fatty acids (FA). CSC were strongly dependent upon activation of lipid biosynthetic pathways; activation of these pathways exhibited an unfavorable prognostic value in a cohort of breast cancer patients where it predicted high probability of metastatic dissemination and tumor relapse. Overall, this work describes a new approach to target aggressive CSC that may substantially improve clinical outcomes for patients with TNBC who currently lack effective targeted therapeutic options.
    DOI:  https://doi.org/10.1158/0008-5472.CAN-19-1184
  3. Theranostics. 2020 ;10(18): 8211-8226
    Yang H, Zhang H, Yang Y, Wang X, Deng T, Liu R, Ning T, Bai M, Li H, Zhu K, Li J, Fan Q, Ying G, Ba Y.
      Hypoxia is one of the important properties of solid tumor. However, oxygen supply within tumors is generally heterogeneous according to the distance from the nearest blood vessel. The discrepancy of metastatic potential exists between hypoxic cancer cells and relatively normoxic cancer cells. But the molecular mechanism remains poorly understood. Methods: Differential expression of circRNAs in plasma exosomes of CRC patients and normal subjects was performed by screening. Exosomes were isolated by ultra-centrifugation and RNA expressions were determined by RT-qPCR. The migratory capacity of cells was performed by high intension imaging, wound healing assay and transwell chamber migration assay. Results: Circ-133 is enriched in the plasma exosomes of CRC patients and increased with the disease progression. Exosomal circ-133 derived from hypoxic cells delivered into normoxic cells and promoted cancer metastasis by acting on miR-133a/GEF-H1/RhoA axis. Meanwhile, animal experiments revealed that knockdown of circ-133 can inhibit tumor metastasis. Circ-133 is expected to be a new biomarker for monitoring tumor progression and might be a novel therapeutic target. Conclusions: Hypoxia-derived exosomal circ-133 transported into normaxic cancer cells and promoted cell migration via miR-133a/GEF-H1/RhoA axis. This study reveals a potential mechanism for that the intra-tumor heterogeneity of oxygen promote cancer progression.
    Keywords:  cancer metastasis; circRNAs; colorectal cancer; exosomes; hypoxia
    DOI:  https://doi.org/10.7150/thno.44419
  4. BMC Med Genomics. 2020 Jul 29. 13(1): 107
    Chen YY, Jiang MJ, Tian L.
      BACKGROUND: Pancreatic cancer is one of the most malignant tumors. However, radiotherapy can lead to tumor recurrence, which is caused by the residual surviving cells repopulation stimulated by some molecular released from dying cells. Exosomes may mediate cell-cell communication and transfer kinds of signals from the dying cells to the surviving cells for stimulating tumor repopulation. Circular RNAs (circRNAs) may be one vital kind of exosomal cargos involving in modulating cancer cell repopulation.METHODS: Next generation sequencing (NGS) and bioinformatics were performed to analyze and annotate the expression and function of exosome-derived circRNAs in pancreatic cancer cells after radiation. Four circRNAs were chosen for qRT-PCR analysis to validate the sequencing results.
    RESULTS: In this study, 3580 circRNAs were annotated in literatures and circBase among 12,572 identified circRNAs. There were 196 filtered differentially expressed circRNAs (the up-regulation and down-regulation respectively is 182 and 14, fold change > 2, p-value < 0.05). Regulation of metabolic process and lysine degradation were the main enriched biological processes and pathway according to Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis.
    CONCLUSIONS: The hsa_circ_0002130-hsa_miR_4482-3p-NBN interaction network suggested potential sponging miRNA and target mRNA. Our results provided potential functions of circRNAs to explore molecular mechanisms and therapeutic targets in pancreatic cancer cell repopulation upon irradiation.
    Keywords:  Cancer repopulation; Circular RNA; Exosome; Gene expression profiling; Irradiation; Pancreatic cancer
    DOI:  https://doi.org/10.1186/s12920-020-00756-3
  5. Theranostics. 2020 ;10(18): 8365-8381
    Liu Q, Hodge J, Wang J, Wang Y, Wang L, Singh U, Li Y, Yao Y, Wang D, Ai W, Nagarkatti P, Chen H, Xu P, Murphy EA, Fan D.
      Our previous studies demonstrated that the natural compound emodin blocks the tumor-promoting feedforward interactions between cancer cells and macrophages, and thus ameliorates the immunosuppressive state of the tumor microenvironment. Since tumor-associated macrophages (TAMs) also affect epithelial mesenchymal-transition (EMT) and cancer stem cell (CSC) formation, here we aimed to test if emodin as a neoadjuvant therapy halts breast cancer metastasis by attenuating TAM-induced EMT and CSC formation of breast cancer cells. Methods: Bioinformatical analysis was performed to examine the correlation between macrophage abundance and EMT/CSC markers in human breast tumors. Cell culture and co-culture studies were performed to test if emodin suppresses TGF-β1 or macrophage-induced EMT and CSC formation of breast cancer cells, and if it inhibits breast cancer cell migration and invasion. Using mouse models, we tested if short-term administration of emodin before surgical removal of breast tumors halts breast cancer post-surgery metastatic recurrence in the lungs. The effects of emodin on TGF-β1 signaling pathways in breast cancer cells were examined by western blots and immunofluorescent imaging. Results: Macrophage abundance positively correlates with EMT and CSC markers in human breast tumors. Emodin suppressed TGF-β1 production in breast cancer cells and macrophages and attenuated TGF-β1 or macrophage-induced EMT and CSC formation of breast cancer cells. Short-term administration of emodin before surgery halted breast cancer post-surgery metastatic recurrence in the lungs by reducing tumor-promoting macrophages and suppressing EMT and CSC formation in the primary tumors. Mechanistic studies revealed that emodin inhibited both canonical and noncanonical TGF-β1 signaling pathways in breast cancer cells and suppressed transcription factors key to EMT and CSC. Conclusion: Natural compound emodin suppresses EMT and CSC formation of breast cancer cells by blocking TGF-β1-mediated crosstalk between TAMs and breast cancer cells. Our study provides evidence suggesting that emodin harbors the potential for clinical development as a new effective and safe agent to halt metastatic recurrence of breast cancer.
    Keywords:  Breast cancer; Cancer stem cell; Emodin; Epithelial-mesenchymal transition; Macrophage
    DOI:  https://doi.org/10.7150/thno.45395
  6. Theranostics. 2020 ;10(18): 8098-8110
    Song X, Shen L, Tong J, Kuang C, Zeng S, Schoen RE, Yu J, Pei H, Zhang L.
      Intrinsic and acquired resistance to targeted therapies is a significant clinical problem in cancer. We previously showed that resistance to regorafenib, a multi-kinase inhibitor for treating colorectal cancer (CRC) patients, can be caused by mutations in the tumor suppressor FBW7, which block degradation of the pro-survival Bcl-2 family protein Mcl-1. We tested if Mcl-1 inhibition can be used to develop a precision combination therapy for overcoming regorafenib resistance.METHODS: Small-molecule Mcl-1 inhibitors were tested on CRC cells with knock-in (KI) of a non-degradable Mcl-1. Effects of Mcl-1 inhibitors on regorafenib sensitivity were determined in FBW7-mutant and -wild-type (WT) CRC cells and tumors, and in those with acquired regorafenib resistance due to enriched FBW7 mutations. Furthermore, translational potential was explored by establishing and analyzing FBW7-mutant and -WT patient-derived organoid (PDO) and xenograft (PDX) tumor models.
    RESULTS: We found that highly potent and specific Mcl-1 inhibitors such as S63845 overcame regorafenib resistance by restoring apoptosis in multiple regorafenib-resistant CRC models. Mcl-1 inhibition re-sensitized CRC tumors with intrinsic and acquired regorafenib resistance in vitro and in vivo, including those with FBW7 mutations. Importantly, Mcl-1 inhibition also sensitized FBW7-mutant PDO and PDX models to regorafenib. In contrast, Mcl-1 inhibition had no effect in FBW7-WT CRCs.
    CONCLUSIONS: Our results demonstrate that Mcl-1 inhibitors can overcome intrinsic and acquired regorafenib resistance in CRCs by restoring apoptotic response. FBW7 mutations might be a potential biomarker predicting for response to the regorafenib/Mcl-1 inhibitor combination.
    Keywords:  FBW7; Mcl-1; apoptosis; colorectal cancer; regorafenib
    DOI:  https://doi.org/10.7150/thno.45363
  7. Nat Commun. 2020 Jul 30. 11(1): 3806
    Li ZL, Zhang HL, Huang Y, Huang JH, Sun P, Zhou NN, Chen YH, Mai J, Wang Y, Yu Y, Zhou LH, Li X, Yang D, Peng XD, Feng GK, Tang J, Zhu XF, Deng R.
      Most triple-negative breast cancer (TNBC) patients fail to respond to T cell-mediated immunotherapies. Unfortunately, the molecular determinants are still poorly understood. Breast cancer is the disease genetically linked to a deficiency in autophagy. Here, we show that autophagy defects in TNBC cells inhibit T cell-mediated tumour killing in vitro and in vivo. Mechanistically, we identify Tenascin-C as a candidate for autophagy deficiency-mediated immunosuppression, in which Tenascin-C is Lys63-ubiquitinated by Skp2, particularly at Lys942 and Lys1882, thus promoting its recognition by p62 and leading to its selective autophagic degradation. High Tenascin-C expression is associated with poor prognosis and inversely correlated with LC3B expression and CD8+ T cells in TNBC patients. More importantly, inhibition of Tenascin-C in autophagy-impaired TNBC cells sensitizes T cell-mediated tumour killing and improves antitumour effects of single anti-PD1/PDL1 therapy. Our results provide a potential strategy for targeting TNBC with the combination of Tenascin-C blockade and immune checkpoint inhibitors.
    DOI:  https://doi.org/10.1038/s41467-020-17395-y
  8. Cell Stem Cell. 2020 Jul 24. pii: S1934-5909(20)30341-6. [Epub ahead of print]
    Cheung P, Xiol J, Dill MT, Yuan WC, Panero R, Roper J, Osorio FG, Maglic D, Li Q, Gurung B, Calogero RA, Yilmaz ÖH, Mao J, Camargo FD.
      Although the Hippo transcriptional coactivator YAP is considered oncogenic in many tissues, its roles in intestinal homeostasis and colorectal cancer (CRC) remain controversial. Here, we demonstrate that the Hippo kinases LATS1/2 and MST1/2, which inhibit YAP activity, are required for maintaining Wnt signaling and canonical stem cell function. Hippo inhibition induces a distinct epithelial cell state marked by low Wnt signaling, a wound-healing response, and transcription factor Klf6 expression. Notably, loss of LATS1/2 or overexpression of YAP is sufficient to reprogram Lgr5+ cancer stem cells to this state and thereby suppress tumor growth in organoids, patient-derived xenografts, and mouse models of primary and metastatic CRC. Finally, we demonstrate that genetic deletion of YAP and its paralog TAZ promotes the growth of these tumors. Collectively, our results establish the role of YAP as a tumor suppressor in the adult colon and implicate Hippo kinases as therapeutic vulnerabilities in colorectal malignancies.
    Keywords:  Hippo signaling; Wnt signaling; colorectal cancer; intestinal stem cells; metastasis; regeneration
    DOI:  https://doi.org/10.1016/j.stem.2020.07.003
  9. Cancer Lett. 2020 Jul 23. pii: S0304-3835(20)30359-1. [Epub ahead of print]
    Terry S, Engelsen AST, Buart S, Elsayed WS, Venkatesh GH, Chouaib S.
      While it is widely accepted that high intratumoral heterogeneity confers serious challenges in the emerging resistance and the subsequent effective therapeutic targeting of cancer, the underlying biology of intratumoral heterogeneity remains elusive. In particular, it remains to be fully elucidated how microenvironmental factors shape genetic and non-genetic heterogeneity, which in turn determine the course of tumor evolution and clinical progression. In this context, hypoxia, a hallmark of most growing cancers, characterized by decreased O2 partial pressure is a key player of the tumor microenvironment. Despite extensive data indicating that hypoxia promotes cellular metabolic adaptation, immune suppression and various steps of tumor progression via hypoxia regulated gene transcription, much less is known about the role of hypoxia in mediating therapy resistance as a driver of tumor evolution through genetic and non-genetic mechanisms. In this review, we will discuss recent evidence supporting a prominent role of hypoxia as a driver of tumor heterogeneity and highlight the multifaceted manner by which this in turn could impact cancer evolution, reprogramming and immune escape. Finally, we will discuss how detailed knowledge of the hypoxic footprint may open up new therapeutic avenues for the management of cancer.
    Keywords:  Antitumor immunity; DNA repair; Epigenetics; Hypoxia; Immune escape; Intratumoral heterogeneity; Tumor plasticity; Tumor resistance
    DOI:  https://doi.org/10.1016/j.canlet.2020.07.004
  10. Trends Cancer. 2020 Jul 25. pii: S2405-8033(20)30191-6. [Epub ahead of print]
    De Marco M, Turco MC, Marzullo L.
      BAG3 is highly expressed across cancer types and its intracellular activity is critical for cancer cell survival. However, recent findings suggest that BAG3 can also modulate the tumor microenvironment to promote cancer progression and resistance to therapies, suggesting new ways to target this protein in cancer therapy.
    Keywords:  BAG3; resistance to therapy
    DOI:  https://doi.org/10.1016/j.trecan.2020.07.001
  11. Clin Cancer Res. 2020 Jul 27. pii: clincanres.2597.2019. [Epub ahead of print]
    Dodd RD, Scherer A, Huang W, McGivney GR, Gutierrez WR, Laverty E, Ashcraft KA, Stephens VR, Yousefpour P, Saha S, Knepper-Adrian VL, Floyd W, Chen M, Ma Y, Mastria EM, Cardona DM, Eward WC, Chilkoti A, Kirsch DG.
      PURPOSE: Nanoparticle-encapsulated drug formulations can improve responses to conventional chemotherapy by increasing drug retention within the tumor and by promoting a more effective anti-tumor immune response than free drug. New drug delivery modalities are needed in sarcomas because they are often chemo-resistant cancers, but the rarity of sarcomas and the complexity of diverse subtypes makes it challenging to investigate novel drug formulations.EXPERIMENTAL DESIGN: New drug formulations can be tested in animal models of sarcomas where the therapeutic response of different formulations can be compared using mice with identical tumor-initiating mutations. Here, using Cre/loxP and CRISPR/Cas9 techniques, we generated two distinct mouse models of Pten-deleted soft-tissue sarcoma: malignant peripheral nerve sheath tumor (MPNST) and undifferentiated pleomorphic sarcoma (UPS). We used these models to test the efficacy of chimeric polypeptide doxorubicin (CP-Dox), a nano-scale micelle formulation, in comparison to free doxorubicin.
    RESULTS: The CP-Dox formulation was superior to free doxorubicin in MPNST models. However, in UPS tumors, CP-Dox did not improve survival in comparison to free doxorubicin. While CP-Dox treatment resulted in elevated intratumoral doxorubicin concentrations in MPNSTs, this increase was absent in UPS tumors. Additionally, elevation of CD8+ T cells was observed exclusively in CP-Dox-treated MPNSTs, although these cells were not required for full efficacy of the CP-nanoparticle-based chemotherapy.
    CONCLUSIONS: These results have important implications for treating sarcomas with nanoparticle-encapsulated chemotherapy by highlighting the tumor subtype-dependent nature of therapeutic response.
    DOI:  https://doi.org/10.1158/1078-0432.CCR-19-2597
  12. Cell Mol Immunol. 2020 Jul 29.
    Liguori M, Digifico E, Vacchini A, Avigni R, Colombo FS, Borroni EM, Farina FM, Milanesi S, Castagna A, Mannarino L, Craparotta I, Marchini S, Erba E, Panini N, Tamborini M, Rimoldi V, Allavena P, Belgiovine C.
      In cancer, myeloid cells have tumor-supporting roles. We reported that the protein GPNMB (glycoprotein nonmetastatic B) was profoundly upregulated in macrophages interacting with tumor cells. Here, using mouse tumor models, we show that macrophage-derived soluble GPNMB increases tumor growth and metastasis in Gpnmb-mutant mice (DBA/2J). GPNMB triggers in the cancer cells the formation of self-renewing spheroids, which are characterized by the expression of cancer stem cell markers, prolonged cell survival and increased tumor-forming ability. Through the CD44 receptor, GPNMB mechanistically activates tumor cells to express the cytokine IL-33 and its receptor IL-1R1L. We also determined that recombinant IL-33 binding to IL-1R1L is sufficient to induce tumor spheroid formation with features of cancer stem cells. Overall, our results reveal a new paracrine axis, GPNMB and IL-33, which is activated during the cross talk of macrophages with tumor cells and eventually promotes cancer cell survival, the expansion of cancer stem cells and the acquisition of a metastatic phenotype.
    Keywords:  GPNMB; IL-33; cancer stem cells; metastasis; tumor associated macrophages
    DOI:  https://doi.org/10.1038/s41423-020-0501-0
  13. Cancers (Basel). 2020 Jul 25. pii: E2054. [Epub ahead of print]12(8):
    Lee EK, Matulonis UA.
      The use of PARP inhibitors (PARPi) is growing widely as FDA approvals have shifted its use from the recurrence setting to the frontline setting. In parallel, the population developing PARPi resistance is increasing. Here we review the role of PARP, DNA damage repair, and synthetic lethality. We discuss mechanisms of resistance to PARP inhibition and how this informs on novel combinations to re-sensitize cancer cells to PARPi.
    Keywords:  BRCA; DNA damage repair; PARP inhibitor; PARP inhibitor resistance; homologous recombination; ovarian cancer; replication fork
    DOI:  https://doi.org/10.3390/cancers12082054
  14. Cancer Discov. 2020 Jul 31.
      A proliferative, chemoresistant cell type and another with metastatic potential were identified.
    DOI:  https://doi.org/10.1158/2159-8290.CD-RW2020-113
  15. Oncogene. 2020 Jul 28.
    Yang H, Geng YH, Wang P, Yang H, Zhou YT, Zhang HQ, He HY, Fang WG, Tian XX.
      Our previous research demonstrated that extracellular adenosine 5'-triphosphate (ATP) could promote breast cancer cell invasion. However, the impact of extracellular ATP on chemoresistance and the mechanisms behind ATP pro-invasion and pro-chemoresistance remain unclear. Here we aimed to determine the molecules or signaling pathways involved. cDNA microarray was performed to identify the differentially expressed genes before and after ATP treatment. As a result, Sex-determining region Y-box 9 (SOX9) was up-regulated after ATP treatment in breast cancer cells. In vitro invasion and migration assays demonstrated that knocking down SOX9 attenuated ATP-driven invasive capability. Mass spectrometry and co-IP revealed that SOX9 interacted with Janus kinase 1 (JAK1). Afterward, IL-6-JAK1-STAT3 signaling was demonstrated to promote SOX9 expression and invasion following ATP treatment. Notably, ATP-IL-6-SOX9 signaling was shown to stimulate chemoresistance in breast cancer cells. ChIP assays identified some potential SOX9 target genes, among which carcinoembryonic antigen-related cell adhesion molecule 5/6 (CEACAM5/6) was demonstrated to mediate ATP pro-invasive function, while ATP-binding cassette subfamily B member 1 (ABCB1) and ATP-binding cassette subfamily G member 2 (ABCG2) mediated ATP-driven chemoresistance. In addition, SOX9-knockdown and apyrase (an ATP hydrolase)-treated MDA-MB-231 cells illustrated decreased tumor growth and enhanced drug sensitivity in nude mice. In vitro spheroid formation assays also proved the significance of ATP-SOX9 in mediating chemoresistance. Moreover, molecules involved in ATP-SOX9 signaling were up-regulated in human breast carcinoma specimens and were associated with poor prognosis. Altogether, SOX9 signaling is vital in ATP-driven invasion and chemoresistance, which may serve as a potential target for breast cancer therapies.
    DOI:  https://doi.org/10.1038/s41388-020-01402-z
  16. Proc Natl Acad Sci U S A. 2020 Jul 27. pii: 201919221. [Epub ahead of print]
    Hoemberger M, Pitsawong W, Kern D.
      Despite the outstanding success of the cancer drug imatinib, one obstacle in prolonged treatment is the emergence of resistance mutations within the kinase domain of its target, Abl. We noticed that many patient-resistance mutations occur in the dynamic hot spots recently identified to be responsible for imatinib's high selectivity toward Abl. In this study, we provide an experimental analysis of the mechanism underlying drug resistance for three major resistance mutations (G250E, Y253F, and F317L). Our data settle controversies, revealing unexpected resistance mechanisms. The mutations alter the energy landscape of Abl in complex ways: increased kinase activity, altered affinity, and cooperativity for the substrates, and, surprisingly, only a modestly decreased imatinib affinity. Only under cellular adenosine triphosphate (ATP) concentrations, these changes cumulate in an order of magnitude increase in imatinib's half-maximal inhibitory concentration (IC50). These results highlight the importance of characterizing energy landscapes of targets and its changes by drug binding and by resistance mutations developed by patients.
    Keywords:  Abl kinase; cancer research; imatinib resistance; tyrosine kinase
    DOI:  https://doi.org/10.1073/pnas.1919221117
  17. Mol Cancer. 2020 Jul 27. 19(1): 117
    Shang A, Gu C, Wang W, Wang X, Sun J, Zeng B, Chen C, Chang W, Ping Y, Ji P, Wu J, Quan W, Yao Y, Zhou Y, Sun Z, Li D.
      BACKGROUND: Colorectal cancer (CRC) is the leading cause of cancer-related death worldwide. Exosome shave emerged as crucial regulators of intercellular communication and that abundant Circular RNAs (circRNAs) are enriched within exosomes. CircRNAs are novel members of noncoding RNAs regulating cancer proliferation and progression. However, the function and regulatory mechanism of cancer-derived exosomal circRNAs in CRC remains unclear.METHODS: CRC cells-derived exosomes were characterized using transmission electron microscopy, nanoparticle tracking analysis (NTA) and western blot. CCK-8, wound healing and transwell assays, and flow cytometry assays were conducted to assess whether exosomes would affect the proliferation, metastasis, and apoptosis of CRC cells, respectively. Moreover, we performed the RNA sequencing and RT-qPCR to identify circRNAs in exosome-stimulated CRC cells. Fluorescence in situ hybridization (FISH) assay was used to detect the cellular distribution of circPACRGL. Bioinformatic analyses (StarBase 2.0) were used to pool the miRNA targets of circPACRGL. Luciferase assays were performed to verify the direct interaction. Finally, flow cytometry was used to detect the differentiation of N1-N2 neutrophils.
    RESULTS: Our study identified a novel CRC-derived exosomal circRNA, circPACRGL. We found circPACRGL was significantly upregulated in CRC cells after tumor-derived exosomes addition. Moreover, circPACRGL serves as a sponge for miR-142-3p/miR-506-3p to facilitate the transforming growth factor-β1 (TGF-β1) expression. As a result, circPACRGL promoted CRC cell proliferation, migration and invasion, as well as differentiation of N1 to N2 neutrophils via miR-142-3p/miR-506-3p-TGF-β1 axis.
    CONCLUSION: Our study, the first to reveal that cancer-derived exosomal circPACRGL plays an oncogenic role in CRC proliferation and metastasis, providing mechanistic insights into the roles of circRNAs in CRC progression and a valuable marker for CRC treatment.
    Keywords:  Colorectal cancer; Exosome; Invasion; Migration; TGF-β1; circPACRGL; miR-142-3p; miR-506-3p
    DOI:  https://doi.org/10.1186/s12943-020-01235-0
  18. Biomaterials. 2020 Jul 02. pii: S0142-9612(20)30463-4. [Epub ahead of print]256 120217
    Qiu Y, Qiu S, Deng L, Nie L, Gong L, Liao X, Zheng X, Jin K, Li J, Tu X, Liu L, Liu Z, Bao Y, Ai J, Lin T, Yang L, Wei Q.
      The high potential for cancer relapse has emerged as a crucial challenge of human bladder cancer treatment. To date, those stem-like bladder cancer cells (BCSCs) have been considered as seeds that induce frequent tumor recurrence. However, the cell origin of cancer stem cells (CSCs) is still a controversial issue, due in part to the findings that CSCs not only origin from normal stem cells but also converted from differentiated tumor cells. Here, we describe a biomaterial 3D collagen I gel culture system, where non-tumorigenic cells can obtain tumorigenic potential and revert back into CSCs through the integrin α2β1/PI3K/AKT/NF-κB cascade, resulting in the tumorigenesis in bladder tissues. Furthermore, inhibiting this integrin α2β1/PI3K/AKT/NF-κB signal pathways can significantly impair the tumorigenic capacity of CSCs. Simultaneously, in vivo studies demonstrate that IFN-γ secreted by T cells can trigger those CSCs into dormancy through the IDO/Kyn/AHR/P27 cascade, which elicit chemotherapy resistance and cancer relapse. To address the challenges of suppressing bladder tumor growth and preventing tumor reoccurrence, we use IDO and integrin α2β1 signal pathway inhibitors combine with chemotherapeutic agents to awaken dormant bladder CSCs and inhibit their tumorigenic ability as well as effectively eliminate CSCs. The therapeutic approaches we propose provide new insights for eradicating tumors and reducing bladder cancer relapse after therapy.
    Keywords:  Biomaterial; Bladder cancer; Collagen; Tumor dormancy; Tumorigenesis
    DOI:  https://doi.org/10.1016/j.biomaterials.2020.120217
  19. Trends Cancer. 2020 Jul 24. pii: S2405-8033(20)30190-4. [Epub ahead of print]
    Deng D, Shah K.
      Tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) induces apoptosis selectively via its interaction with the death receptors TRAILR1/DR4 and TRAILR2/DR5 in a wide range of cancers, while sparing normal cells. Despite its tremendous potential for cancer therapeutics, the translation of TRAIL into the clinic has been confounded by TRAIL-resistant cancer populations. We discuss different molecular mechanisms underlying TRAIL-mediated apoptosis and resistance to TRAIL. We also discuss the successes and failures of recent preclinical and clinical studies of TRAIL-induced apoptosis, and current attempts to overcome TRAIL resistance, and we provide a perspective for improving the prospects of future clinical implementation.
    Keywords:  TRAIL; apoptosis; cancer; therapeutic resistance
    DOI:  https://doi.org/10.1016/j.trecan.2020.06.006
  20. Cancer Res. 2020 Jul 31. pii: canres.0560.2020. [Epub ahead of print]
    Feng J, Lu SS, Xiao T, Huang W, Yi H, Zhu W, Fan S, Feng XP, Li JY, Yu ZZ, Gao S, Nie GH, Tang YY, Xiao ZQ.
      Overexpression of ANXA1 and EphA2 has been linked to various cancers and both proteins have attracted considerable attention for the development of new anti-cancer drugs. Here we report that ANXA1 competes with Cbl for binding EphA2 and increases its stability by inhibiting Cbl-mediated EphA2 ubiquitination and degradation in nasopharyngeal carcinoma (NPC). Binding of ANXA1 to EphA2 promoted NPC cell growth and metastasis in vitro and in vivo by elevating EphA2 levels and increasing activity of EphA2 oncogenic signaling (pS897-EphA2). Expression of ANXA1 and EphA2 was positively correlated and both were significantly higher in NPC tissues than in the normal nasopharyngeal epithelial tissues. Patients with high expression of both proteins presented poorer disease-free survival and overall survival relative to patients with high expression of one protein alone. Furthermore, amino acid residues 20-30aa and 28-30aa of the ANXA1 N-terminus bound EphA2. An eleven amino acid-long ANXA1-derived peptide (EYVQTVKSSKG) was developed based on this N-terminal region, which disrupted the connection of ANXA1 with EphA2, successfully downregulating EphA2 expression and dramatically suppressing NPC cell oncogenicity in vitro and in mice. These findings suggest that ANXA1 promotes NPC growth and metastasis via binding and stabilization of EphA2 and present a strategy for targeting EphA2 degradation and treating NPC with a peptide. This therapeutic strategy may also be extended to other cancers with high expression of both proteins.
    DOI:  https://doi.org/10.1158/0008-5472.CAN-20-0560
  21. Nat Commun. 2020 Jul 30. 11(1): 3811
    Zhou W, Yao Y, Scott AJ, Wilder-Romans K, Dresser JJ, Werner CK, Sun H, Pratt D, Sajjakulnukit P, Zhao SG, Davis M, Nelson BS, Halbrook CJ, Zhang L, Gatto F, Umemura Y, Walker AK, Kachman M, Sarkaria JN, Xiong J, Morgan MA, Rehemtualla A, Castro MG, Lowenstein P, Chandrasekaran S, Lawrence TS, Lyssiotis CA, Wahl DR.
      Intratumoral genomic heterogeneity in glioblastoma (GBM) is a barrier to overcoming therapy resistance. Treatments that are effective independent of genotype are urgently needed. By correlating intracellular metabolite levels with radiation resistance across dozens of genomically-distinct models of GBM, we find that purine metabolites, especially guanylates, strongly correlate with radiation resistance. Inhibiting GTP synthesis radiosensitizes GBM cells and patient-derived neurospheres by impairing DNA repair. Likewise, administration of exogenous purine nucleosides protects sensitive GBM models from radiation by promoting DNA repair. Neither modulating pyrimidine metabolism nor purine salvage has similar effects. An FDA-approved inhibitor of GTP synthesis potentiates the effects of radiation in flank and orthotopic patient-derived xenograft models of GBM. High expression of the rate-limiting enzyme of de novo GTP synthesis is associated with shorter survival in GBM patients. These findings indicate that inhibiting purine synthesis may be a promising strategy to overcome therapy resistance in this genomically heterogeneous disease.
    DOI:  https://doi.org/10.1038/s41467-020-17512-x
  22. Mol Cancer. 2020 Jul 29. 19(1): 118
    Zhou C, Yi C, Yi Y, Qin W, Yan Y, Dong X, Zhang X, Huang Y, Zhang R, Wei J, Ali DW, Michalak M, Chen XZ, Tang J.
      BACKGROUND: Pancreatic cancer is one of the most lethal malignancies and has an extremely poor diagnosis and prognosis. The development of resistance to gemcitabine is still a major challenge. The long noncoding RNA PVT1 was reported to be involved in carcinogenesis and chemoresistance; however, the mechanism by which PVT1 regulates the sensitivity of pancreatic cancer to gemcitabine remains poorly understood.METHODS: The viability of pancreatic cancer cells was assessed by MTT assay in vitro and xenograft tumor formation assay in vivo. The expression levels of PVT1 and miR-619-5p were detected by quantitative real-time polymerase chain reaction (qRT-PCR). Western blotting analysis and qRT-PCR were performed to assess the protein and mRNA levels of Pygo2 and ATG14, respectively. Autophagy was explored via autophagic flux detection under confocal microscopy and autophagic vacuole investigation under transmission electron microscopy (TEM). The functional role and mechanism of PVT1 were further investigated by gain- and loss-of-function assays in vitro.
    RESULTS: In the present study, we demonstrated that PVT1 was up-regulated in gemcitabine-resistant pancreatic cancer cell lines. Gain- and loss-of-function assays revealed that PVT1 impaired sensitivity to gemcitabine in vitro and in vivo. We further found that PVT1 up-regulated the expression of both Pygo2 and ATG14 and thus regulated Wnt/β-catenin signaling and autophagic activity to overcome gemcitabine resistance through sponging miR-619-5p. Moreover, we discovered three TCF/LEF binding elements (TBEs) in the promoter region of PVT1, and activation of Wnt/β-catenin signaling mediated by the up-regulation of Pygo2 increased PVT1 expression by direct binding to the TBE region. Furthermore, PVT1 was discovered to interact with ATG14, thus promoting assembly of the autophagy specific complex I (PtdIns3K-C1) and ATG14-dependent class III PtdIns3K activity.
    CONCLUSIONS: These data indicate that PVT1 plays a critical role in the sensitivity of pancreatic cancer to gemcitabine and highlight its potential as a valuable target for pancreatic cancer therapy.
    Keywords:  Autophagy; Gemcitabine resistance; PVT1; Wnt/β-catenin; miR-619-5p
    DOI:  https://doi.org/10.1186/s12943-020-01237-y
  23. Cancers (Basel). 2020 Jul 23. pii: E2022. [Epub ahead of print]12(8):
    Emmanouilidi A, Casari I, Gokcen Akkaya B, Maffucci T, Furic L, Guffanti F, Broggini M, Chen X, Maxuitenko YY, Keeton AB, Piazza GA, Linton KJ, Falasca M.
      Expression of ATP-binding cassette (ABC) transporters has long been implicated in cancer chemotherapy resistance. Increased expression of the ABCC subfamily transporters has been reported in prostate cancer, especially in androgen-resistant cases. ABCC transporters are known to efflux drugs but, recently, we have demonstrated that they can also have a more direct role in cancer progression. The pharmacological potential of targeting ABCC1, however, remained to be assessed. In this study, we investigated whether the blockade of ABCC1 affects prostate cancer cell proliferation using both in vitro and in vivo models. Our data demonstrate that pharmacological inhibition of ABCC1 reduced prostate cancer cell growth in vitro and potentiated the effects of Docetaxel in vitro and in mouse models of prostate cancer in vivo. Collectively, these data identify ABCC1 as a novel and promising target in prostate cancer therapy.
    Keywords:  ABC transporter; ABCC1/MRP1; Docetaxel; lysophosphatidylinositol; prostate cancer
    DOI:  https://doi.org/10.3390/cancers12082022
  24. J Biol Chem. 2020 Jul 31. pii: jbc.RA120.014976. [Epub ahead of print]
    Shi Y, Wang X, Xu Z, He Y, Guo C, He L, Huan C, Cai C, Huang J, Zhang J, Li Y, Zeng C, Zhang X, Wang L, Ke Y, Cheng H.
      Transforming growth factor β (TGFβ) signaling plays an important role in regulating tumor malignancy, including in non-small cell lung cancer (NSCLC). The major biological responses of TGFβ signaling are determined by the effector proteins SMAD2 and SMAD3. However, the regulators of TGFβ-SMADs signaling are not completely revealed yet. Here, we showed that the scaffolding protein PDZ and LIM domain protein 5 (PDLIM5, ENH) critically promotes TGFβ signaling by maintaining SMAD3 stability in NSCLC. Firstly, PDLIM5 was highly expressed in NSCLC compared with that in adjacent normal tissues, and high PDLIM5 expression was associated with poor outcome. Knockdown of PDLIM5 in NSCLC cells decreased migration and invasion in vitro, and lung metastasis in vivo. In addition, TGFβ signaling and TGFβ-induced epithelial-mesenchymal transition (EMT) was repressed by PDLIM5 knockdown. Mechanistically, PDLIM5 knockdown resulted in a reduction of SMAD3 protein levels. Overexpression of SMAD3 reversed the TGFβ-signaling-repressing and anti-migration effects induced by PDLIM5 knockdown. Notably, PDLIM5 interacted with SMAD3 but not SMAD2, and competitively suppressed the interaction between SMAD3 and its E3 ubiquitin ligase STUB1. Therefore, PDLIM5 protected SMAD3 from STUB1-mediated proteasome degradation. STUB1 knockdown restored SMAD3 protein levels, cell migration and invasion in PDLIM5-knockdown cells. Collectively, our findings indicate that PDLIM5 is a novel regulator of basal SMAD3 stability, with implications for controlling TGFβ signaling and NSCLC progression.
    Keywords:  E3 ubiquitin ligase; cell invasion; cell motility; enh; invasion; lung cancer; proteasome degradation; protein degradation; signal transduction; stub1; transforming growth factor beta (TGF-B); tumor metastasis; ubiquitin
    DOI:  https://doi.org/10.1074/jbc.RA120.014976
  25. Cancers (Basel). 2020 Jul 27. pii: E2069. [Epub ahead of print]12(8):
    Shen HT, Chien PJ, Chen SH, Sheu GT, Jan MS, Wang BY, Chang WW.
      Lung cancer is the leading cause of cancer death worldwide and the therapeutic strategies include surgery, chemotherapy and radiation therapy. Non-small cell lung cancers (NSCLCs) account for around 85% of cases of lung cancers. Pemetrexed is an antifolate agent that is currently used as the second line chemotherapy drug in the treatment of advanced NSCLC patients with a response rate of 20-40%. The search for any combination therapy to improve the efficacy of pemetrexed is required. The existence of cancer stem cells (CSCs) is considered as the main reason for drug resistance of cancers. In this study, we first found that pemetrexed-resistant NSCLC cells derived from A549 cells displayed higher CSC activity in comparison to the parental cells. The expression of CSC related proteins, such as BMI1 or CD44, and the epithelial-mesenchymal transition (EMT) signature was elevated in pemetrexed-resistant NSCLC cells. We next discovered that the overexpression of BMI1 in A549 cells caused the pemetrexed resistance and inhibition of BMI1 by a small molecule inhibitor, PTC-209, or transducing of BMI1-specific shRNAs suppressed cell growth and the expression of thymidylate synthase (TS) in pemetrexed-resistant A549 cells. We further identified that BMI1 positively regulated SP1 expression and treatment of mithramycin A, a SP1 inhibitor, inhibited cell proliferation, as well as TS expression, of pemetrexed-resistant A549 cells. Furthermore, overexpression of BMI1 in A549 cells also caused the activation of EMT in and the enhancement of CSC activity. Finally, we demonstrated that pretreatment of PTC-209 in mice bearing pemetrexed-resistant A549 tumors sensitized them to pemetrexed treatment and the expression of Ki-67, BMI1, and SP1 expression in tumor tissues was observed to be reduced. In conclusion, BMI1 expression level mediates pemetrexed sensitivity of NSCLC cells and the inhibition of BMI1 will be an effective strategy in NSCLC patients when pemetrexed resistance has developed.
    Keywords:  BMI1; SP1; cancer stem cells; epithelial–mesenchymal transition; non small cell lung cancer; pemetrexed resistance
    DOI:  https://doi.org/10.3390/cancers12082069
  26. Cancers (Basel). 2020 Jul 25. pii: E2058. [Epub ahead of print]12(8):
    Sfakianaki M, Papadaki C, Tzardi M, Trypaki M, Manolakou S, Messaritakis I, Saridaki Z, Athanasakis E, Mavroudis D, Tsiaoussis J, Gouvas N, Souglakos J.
      The purpose of the current study is to investigate the prognostic significance of M2 isoform of pyruvate kinase (PKM2) mRNA expression loss in patients with operable colon cancer (CC). Two hundred sixty-two specimens from patients with stage-III or high-risk stage-II CC (group-A) treated with adjuvant fluoropyrimidine and oxaliplatin chemotherapy (FOLFOX), 118 specimens from metastatic CC patients (group-B) treated with FOLFOX, and 104 metastatic CC patients (group-C) treated with irinotecan-based chemotherapy were analyzed for PKM2, TS, ERCC1, MYC, and NEDD9 mRNA expression, as well as KRAS exon2 and BRAFV600E mutations. High PKM2 mRNA expression was correlated with left-sided located primaries (p = 0.001, group-A; p = 0.003, group-B; p = 0.001, group-C), high-grade tumors (p = 0.001, group-A; p = 0.017, group-B; p = 0.021, group-C), microsatellite-stable tumors (p < 0.001, group-A), pericolic lymph nodes involvement (p = 0.018, group-A), and cMYC mRNA expression (p = 0.002, group-A; p = 0.008, group-B; p = 0.006, group-C). High PKM2 mRNA expression was correlated with significantly lower disease free survival (DFS) (p = 0.002) and overall survival (OS) (p = 0.001) in the group-A. Similarly, PKM2 mRNA expression was associated with significantly decreased progression free survival (PFS) (p = 0.001) and OS (p = 0.001) in group-B. On the contrary, no significant association for the PKM2 mRNA expression has been observed with either PFS (p = 0.612) or OS (p = 0.517) in group-C. To conclude, the current study provides evidence for the prediction of PKM2 mRNA expression oxaliplatin-based treatment resistance.
    Keywords:  BRAF; MSI; PKM2; colon cancer; prediction; ΚRAS
    DOI:  https://doi.org/10.3390/cancers12082058
  27. Cancers (Basel). 2020 Jul 24. pii: E2049. [Epub ahead of print]12(8):
    Graziano F, Fischer NW, Bagaloni I, Di Bartolomeo M, Lonardi S, Vincenzi B, Perrone G, Fornaro L, Ongaro E, Aprile G, Bisonni R, Prisciandaro M, Malkin D, Gariépy J, Fassan M, Loupakis F, Sarti D, Del Prete M, Catalano V, Alessandroni P, Magnani M, Ruzzo A.
      Loss of p53 promotes vascular endothelial growth factor (VEGF)-A up-regulation and the angiogenic potential of cancer cells. We investigated TP53 somatic mutations in 110 primary gastric adenocarcinomas of two retrospective metastatic series including 48 patients treated with second-line Ramucirumab/Paclitaxel and 62 patients who received first-line chemotherapy with Cisplatin or Oxaliplatin plus 5-Fluorouracil. Missense mutations were classified by tumor protein p53 (TP53) mutant-specific residual transcriptional activity scores (TP53RTAS) and used to stratify patients into two groups: transcriptionally TP53Active and TP53Inactive. The primary endpoint was overall survival (OS). An additional analysis was addressed to measure VEGF/VEGF receptor 2 (VEGFR2) expression levels in relation to the TP53RTAS. In the Ramucirumab/Paclitaxel group, 29/48 (60.4%) patients had TP53 mutations. Ten patients with TP53Inactive mutations showed better OS than carriers of other TP53 mutations. This effect was retained in the multivariate model analysis (Hazard Ratio = 0.29, 95% confidence interval = 0.17-0.85, p = 0.02). In the chemotherapy group, 41/62 (66%) patients had TP53 mutations, and the 11 carriers of TP53Inactive mutations showed the worst OS (Hazard Ratio = 2.64, 95% confidence interval = 1.17-5.95, p = 0.02). VEGF-A mRNA expression levels were significantly increased in TP53Inactive cases. Further studies are warranted to explore the effect of TP53Inactive mutations in different anti-cancer regimens. This information would lead to new tailored therapy strategies for this lethal disease.
    Keywords:  Paclitaxel; Ramucirumab; TP53; angiogenesis; gastric cancer
    DOI:  https://doi.org/10.3390/cancers12082049
  28. Nat Biotechnol. 2020 Jul 27.
    Umkehrer C, Holstein F, Formenti L, Jude J, Froussios K, Neumann T, Cronin SM, Haas L, Lipp JJ, Burkard TR, Fellner M, Wiesner T, Zuber J, Obenauf AC.
      We developed a functional lineage tracing tool termed CaTCH (CRISPRa tracing of clones in heterogeneous cell populations). CaTCH combines precise clonal tracing of millions of cells with the ability to retrospectively isolate founding clones alive before and during selection, allowing functional experiments. Using CaTCH, we captured rare clones representing as little as 0.001% of a population and investigated the emergence of resistance to targeted melanoma therapy in vivo.
    DOI:  https://doi.org/10.1038/s41587-020-0614-0
  29. Mol Ther. 2020 Jul 21. pii: S1525-0016(20)30370-1. [Epub ahead of print]
    Han M, Qian X, Cao H, Wang F, Li X, Han N, Yang X, Yang Y, Dou D, Hu J, Wang W, Han J, Zhang F, Dong H.
      The regulatory mechanism of long non-coding RNAs (lncRNAs) in trastuzumab resistance is not well established to date. In this research, we identified differentially expressed lncRNA and investigated its regulatory role in trastuzumab resistance of breast cancer. HiSeq sequencing and quantitative real-time PCR were performed to identify the dysregulated lncRNAs. Mass spectrometry, RNA fluorescence in situ hybridization (RNA-FISH), and immunoprecipitation assays were performed to identify the direct interactions between ZNF649-AS1 and other associated targets, such as polypyrimidine tract binding protein 1 (PTBP1) and autophagy related 5 (ATG5). Our results showed that ZNF649-AS1 was more highly expressed in trastuzumab-resistant cells compared to sensitive cells. Increased expression of ZNF649-AS1 was associated with a poorer response and shorter survival time of breast cancer patients. ZNF649-AS1 was upregulated by H3K27ac modification at the presence of trastuzumab treatment, and knockdown of ZNF649-AS1 reversed trastuzumab resistance via modulating ATG5 expression and autophagy. Mechanically, ZNF649-AS1 was associated with PTBP1 protein, which further promoted the transcription activity of the ATG5 gene. In conclusion, we demonstrated that H3K27ac modification-induced upregulation of ZNF649-AS1 could cause autophagy and trastuzumab resistance through associating with PTBP1 and promoting ATG5 transcription.
    Keywords:  ATG5; ZNF649-AS1; autophagy; breast cancer; trastuzumab resistance
    DOI:  https://doi.org/10.1016/j.ymthe.2020.07.019
  30. Cell Rep. 2020 Jul 28. pii: S2211-1247(20)30933-5. [Epub ahead of print]32(4): 107952
    Sheng X, Lin Z, Lv C, Shao C, Bi X, Deng M, Xu J, Guerrero-Juarez CF, Li M, Wu X, Zhao R, Yang X, Li G, Liu X, Wang Q, Nie Q, Cui W, Gao S, Zhang H, Liu Z, Cong Y, Plikus MV, Lengner CJ, Andersen B, Ren F, Yu Z.
      A certain number of epithelial cells in intestinal crypts are DNA damage resistant and contribute to regeneration. However, the cellular mechanism underlying intestinal regeneration remains unclear. Using lineage tracing, we show that cells marked by an Msi1 reporter (Msi1+) are right above Lgr5high cells in intestinal crypts and exhibit DNA damage resistance. Single-cell RNA sequencing reveals that the Msi1+ cells are heterogeneous with the majority being intestinal stem cells (ISCs). The DNA damage-resistant subpopulation of Msi1+ cells is characterized by low-to-negative Lgr5 expression and is more rapidly cycling than Lgr5high radiosensitive crypt base columnar stem cells (CBCs). This enables an efficient repopulation of the intestinal epithelium at early stage when Lgr5high cells are not emerging. Furthermore, relative to CBCs, Msi1+ cells preferentially produce Paneth cells during homeostasis and upon radiation repair. Together, we demonstrate that the DNA damage-resistant Msi1+ cells are cycling ISCs that maintain and regenerate the intestinal epithelium.
    Keywords:  DNA damage response; Msi1; epithelial regeneration; intestinal stem cells
    DOI:  https://doi.org/10.1016/j.celrep.2020.107952
  31. Theranostics. 2020 ;10(18): 8036-8050
    Cui J, Shu C, Xu J, Chen D, Li J, Ding K, Chen M, Li A, He J, Shu Y, Yang L, Zhang R, Zhou J.
      Background: JWA gene is known to down-regulate SP1 and reduces the expression level of Integrin αvβ3. Here, we identified a functional polypeptide (JP1) based on the active fragment of the JWA protein to suppress melanoma growth and metastasis by inhibiting the Integrin αvβ3. Methods: We conducted a series of melanoma growth and metastasis mouse models to evaluate anti-melanoma effect of JP1 peptide. 18F-labeled JP1 (18F-NFP-JP1) was detected by Micro-PET assay to demonstrate drug biodistribution. Toxicity test in cynomolgus monkeys and pharmacokinetic studies in rats were done to assess the druggability. The expression of MEK1/2, NEDD4L, SP1 and Integrin αvβ3 were detected in vitro and vivo models. Results: The peptide JP1 with the best anticancer effect was obtained. Micro-PET assay showed that JP1 specifically targeting to melanoma cells in vivo. JP1 inhibited melanoma growth, metastasis, and prolonged the survival of mouse. JP1 reduced the dosage and toxicity in combination with DTIC in melanoma xenograft and allograft mouse models. Cynomolgus monkey toxicity test showed no observed adverse effect level (NOAEL) of JP1 was 150 mg/kg. Mechanistically, JP1 was shown to activate p-MEK1/2 and triggered SP1 ubiquitination in melanoma cells. NEDD4L, an E3 ubiquitin ligase, was activated by p-MEK1/2 and to ubiquitinate SP1 at K685 site, resulting in subsequent degradation. Conclusions: JP1 was developed as a novel peptide that indicated therapeutic roles on proliferation and metastasis of melanoma through the NEDD4L-SP1-Integrin αvβ3 signaling.
    Keywords:  NEDD4L; SP1; integrin αvβ3.; melanoma; therapeutic peptide
    DOI:  https://doi.org/10.7150/thno.45843