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MicroRNAs upregulated in cancer associated fibroblasts following gemctiabine treatment

ABSTRACT: Cancer associated fibroblasts (CAFs) comprise the majority of the tumor bulk of pancreatic adenocarcinomas (PDACs). Current efforts to eradicate these tumors focus predominantly on targeting the proliferation of rapidly growing cancer epithelial cells. We know that this is largely ineffective with resistance arising in most tumors following exposure to chemotherapy. Despite the long-standing recognition of the prominence of CAFs in PDAC, the effect of chemotherapy on CAFs and how they may contribute to drug resistance in neighboring cancer cells is not well characterized. Here we show that CAFs exposed to chemotherapy play an active role in regulating the survival and proliferation of cancer cells. We found that CAFs are intrinsically resistant to gemcitabine, the chemotherapeutic standard of care for PDAC. Further, CAFs exposed to gemcitabine significantly increase the release of extracellular vesicles called exosomes. These exosomes increased chemoresistance-inducing factor, Snail, in recipient epithelial cells and promote proliferation and drug resistance. Finally, treatment of gemcitabine-exposed CAFs with an inhibitor of exosome release, GW4869, significantly reduces survival in co-cultured epithelial cells, signifying an important role of CAF exosomes in chemotherapeutic drug resistance. Collectively, these findings show the potential for exosome inhibitors as treatment options alongside chemotherapy for overcoming PDAC chemoresistance.

ORGANISM(S): Homo sapiens

PROVIDER: GSE85048 | GEO | 2016/11/01

SECONDARY ACCESSION(S): PRJNA336021

REPOSITORIES: GEO

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Project description:Chemoresistance to gemcitabine limits its clinical implementation for pancreatic ductal adenocarcinoma (PDAC). We previously generated an antibody drug conjugate (ADC) -like agent, EGFR/HER2 dual-targeting ligand-based lidamycin (DTLL), and studied the effect of DTLL combined with gemcitabine and the potential role of SMAD4 in the chemoresistance of PDAC. On the basis of SMAD4 profiles in in vitro and in vivo models, we investigated the antitumor effects of DTLL, gemcitabine and their combination, followed with mechanistic characterization. The results suggested that DTLL combination treatment with gemcitabine significantly repressed tumors with remarkably enhanced efficacy as compared to gemcitabine or DTLL alone given in either SMAD4-deficient/gemcitabine-resistant or SMAD4-sufficient/gemcitabine-sensitive cell line derived xenograft (CDX) and patient derived xenograft (PDX) tumors, respectively. Functional studies indicated that SMAD4 genetic status is responsible for SMAD4 protein level which determines different cellular susceptibility of PDAC. R100T mutation contributes to loss of SMAD4 protein and function with rapid protein degradation, leading to resistance to gemcitabine in PDAC cells. Moreover, DTLL significantly altered the protein half-life time and level of mutant and wild-type SMAD4 by inhibiting protein degradation at different velocities and distinctly changing the interaction of SMAD4 with TRIM33. Mechanism studies implied that DTLL combinational treatment might not only prevent from neoplastic proliferation via blockage of ATK/mTOR signaling and anti-apoptotic proteins (Bcl-2 and MCL1) mediated by impaired NF-B function in SMAD4-sufficient/gemcitabine-sensitive PDAC cells, but also restore the bioactivity of SMAD4 as a tumor suppressor to trigger its downstream NF-B-regulated signaling of cell apoptosis in SMAD4-deficient/gemcitabine-resistant tumors. In conclusion, SMAD4 is the key central mediator of not only the occurrence and development but also susceptibility in PDAC. DTLL sensitized gemcitabine efficacy via distinct action mechanisms based on SMAD4 profiles in SMAD4-sufficient/gemcitabine-sensitive and SMAD4-deficient/-resistant PDAC, respectively. Our findings provide insight into a rational SMAD4-directed precision treatment strategy and reveal a promising DTLL combination therapy to overcome chemoresistance in gemcitabine-resistant PDAC.

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MicroRNAs upregulated in cancer associated fibroblasts following gemctiabine treatment

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