MiR-1266 Contributes to Pancreatic Cancer Progression and Chemoresistance by the STAT3 and NF-?B Signaling Pathways.
ABSTRACT: Pancreatic cancer is characterized by chemoresistance after several cycles of chemotherapy, which is a major issue responsible for treatment failure of pancreatic cancer. Therefore, it is necessary to explore the specific mechanism underlying chemotherapeutic resistance to overcome this issue. Here we report that miR-1266 is dramatically elevated and correlates with poor survival and chemotherapy response in pancreatic cancer patients. Upregulation of miR-1266 enhanced the chemoresistance of pancreatic cancer cells to gemcitabine (GEM) in vitro and in vivo; conversely, inhibition of miR-1266 yielded the opposite effect. Importantly, silencing of miR-1266 restored the sensitivity of pancreatic cancer cells to GEM in a dose-dependent manner in vivo. Furthermore, our results demonstrate that miR-1266 promotes resistance of pancreatic cancer cells to GEM by targeting multiple negative regulators of the STAT3 and NF-?B pathways, including SOCS3, PTPN11, ITCH, and TNIP1, leading to constitutive activation of STAT3 and NF-?B signaling. Thus, our findings clarify a novel mechanism by which miR-1266 induces chemotherapeutic resistance in pancreatic cancer, indicating that miR-1266 may be used as chemotherapeutic response indicator. Antagomir-1266 as a chemotherapeutic sensitizer, in combination with GEM, may serve as a rational regimen in the treatment of chemotherapy-resistant pancreatic cancer.
Project description:Chemoresistance associated with cancer stem cells (CSCs), which is now being held responsible for the pervasive therapy resistance of pancreatic cancer, poses a major challenge to the successful management of this devastating malignancy. However, the molecular mechanism underlying the marked chemoresistance of pancreatic CSCs remains largely unknown. Here we show that JNK, which is upregulated in pancreatic CSCs and contributes to their maintenance, is critically involved in the resistance of pancreatic CSCs to 5-fluorouracil (5-FU) and gemcitabine (GEM). We found that JNK inhibition effectively sensitizes otherwise chemoresistant pancreatic CSCs to 5-FU and GEM. Significantly, JNK inhibition promoted 5-FU- and GEM-induced increase in intracellular reactive oxygen species (ROS), and scavenging intracellular ROS by use of N-acetylcysteine impaired JNK inhibition-mediated promotion of the cytotoxicity of 5-FU and GEM. Our findings thus suggest that JNK may contribute to the chemoresistance of pancreatic CSCs through prevention of chemotherapeutic agents-induced increase in intracellular ROS. Our findings also suggest that JNK inhibition combined with 5-FU- and/or GEM-based regimens may be a rational therapeutic approach to effectively eliminate pancreatic CSCs.
Project description:Background: Dysregulated microRNA (miRNA) expression in cancer can act as a key factor that modifies biological processes, including chemoresistance. Our study aimed to identify the miRNAs associated with gemcitabine (GEM) resistance in pancreatic ductal adenocarcinoma (PDAC) and to explore the potential mechanisms. Methods: The miRNA microarray was used to identify miRNAs associated with GEM resistance. Quantitative real-time PCR was used to examine miR-146a-5p expression in paired PDAC and adjacent normal tissues. Bioinformatics analysis, luciferase reporter assays, and chromatin immunoprecipitation assays were used to confirm tumor necrosis factor receptor-associated factor 6 (TRAF6) as a direct target of miR-146a-5p and to explore the potential transcription factor binding and regulation by miR-146a-5p. In vitro and in vivo experiments were performed to investigate the mechanisms. Results: MiR-146a-5p expression was significantly decreased in PDAC tissues compared with adjacent normal tissues, and miR-146a-5p expression correlated with prognosis in PDAC patients. Functional studies indicated that miR-146a-5p suppressed PDAC cell proliferation and sensitized PDAC cells to GEM chemotherapy by targeting the 3'-untranslated region (3'-UTR) of TRAF6. MiR-146a-5p was also observed to downregulate the TRAF6/NF-?B p65/P-gp axis, which regulates PDAC cell growth and chemoresistance. Conclusions: Taken together, the results indicate that the miR-146a-5p/TRAF6/NF-?B p65 axis drives pancreatic chemoresistance by regulating P-gp, suggesting that miR-146a-5p may be utilized as a new therapeutic target and prognostic marker in PDAC patients.
Project description:Gemcitabine-based chemotherapy is the most common treatment option for pancreatic ductal adenocarcinoma (PDAC). However, it offers little therapeutic value in many cases due to the rapid development of chemoresistance. MicroRNAs (miRNAs) have been found to play pivotal roles in the chemotherapeutic resistance of PDAC. We found that miR-410-3p was significantly down-regulated in human pancreatic cancer xenograft (HPCx) tumor tissues from gemcitabine-treated mice. Low miR-410-3p expression correlated with gemcitabine resistance in HPCx tumors and PDAC cells as well as poor prognosis in PDAC patients. We also found that miR-410-3p attenuated the gemcitabine resistance of PDAC by targeting the 3'-UTR of HMGB1. Moreover, our study clearly demonstrated that miR-410-3p enhanced chemosensitivity to gemcitabine via inhibiting HMGB1-induced autophagy during chemotherapy in PDAC cells. Our study suggests that miR-410-3p expression may be a useful indicator of the potential for chemoresistance to gemcitabine and provide a potential new therapeutic target for chemoresistance in PDAC.
Project description:Gemcitabine (GEM), a first-line chemotherapy for pancreatic cancer undergoes rapid metabolism and develops chemoresistance after repeated administration. We previously demonstrated that the combination of GEM and miR-205 provides an effective therapeutic strategy to sensitize GEM-resistant pancreatic cancer cells. Since epidermal growth factor receptor (EGFR) is overexpressed in pancreatic cancer cells, in this study, we aimed to deliver mixed micelles containing GEM and miR-205 decorated with EGFR-targeting cetuximab (C225) monoclonal antibody for targeted therapy. Cetuximab C225 was conjugated to malemido-poly(ethylene glycol)-block-poly(2-methyl-2-carboxyl-propylene carbonate-graft-dodecanol (C225-PEG-PCD) to prepare mixed micelles with mPEG-b-PCC-g-GEM-g-DC-g-TEPA for targeted codelivery of GEM and miR-205. This mixed micelle formulation showed a significant enhancement in EGFR-mediated cellular uptake in GEM-resistant MIA PaCa-2R cells. Further, an enhanced tumor accumulation of C225-micelles conjugated with near-infrared fluorescent Cy7.5 dye and Dy677-labeled miR-205 in orthotopic pancreatic tumor bearing NSG mice was evident after systemic administration. In addition, inhibition of tumor growth was also observed with increased apoptosis and reduced EMT after treatment with C225-micelles containing GEM and miR-205. Therefore, we believe that the targeted delivery of GEM and miR-205 in combination could be a novel strategy for treating advanced pancreatic cancer.
Project description:Background:Pancreatic cancer is one of the most common malignant diseases in the world. Gemcitabine chemotherapy remains the most important clinical treatment. However, research found that pancreatic cancer cells have chemoresistance to gemcitabine and the effect is not satisfactory. Therefore, it is urgent to find an effective early diagnosis and treatment strategy. Circular RNA is one of the most popular prognostic biomarkers in GEM-resistant PC. Materials and Methods:The present study was designed to evaluate the role of circHIPK3 in PC. The expression of circHIPK3 in PC tissues and cells and its effect on proliferation, migration, invasion, EMT, and apoptosis were investigated in vitro; its effect on tumor xenografts was assessed in vivo. Used bioinformation analysis to predict which miRNAs could potentially interact with circHIPK3, mRNA, and miR-330-5p. Results:RT-PCR showed that the level of circHIPK3 was increased in PC tumor tissues; moreover, circHIPK3 was also increased in GEM-resistant PC tumors tissues and GEM-resistant PC cells. Sh-circHIPK3 could knockdown circHIPK3 in PANC-1-GEM and SW-1990-GEM and could significantly inhibit cell proliferation, invasion, migration, EMT and enhance cell apoptosis, compare with control group, the tumor xenografts of circHIPK3 knockdown group were significantly smaller. CircHIPK3 served as a sponge for miR-330-5p, and miR-330-5p directly bound to the 3' UTR of RASSF1 were revealed by dual luciferase assay and RIP in PC cells. CircHIPK3 knockdown of RASSF1 expression could neutralize the cytological function of PC cells by miR-330-5p inhibitor mediated GEM-resistance. Conclusion:CircHIPK3 promotes gemcitabine (GEM) resistance in pancreatic cancer cells by targeting RASSF1 via miR-330-5p and regulates proliferation, invasive, migration, EMT, and apoptosis. Our research revealed that circHIPK3 may be a novel biomarker in GEM-resistant PC and could be used as a prognostic target.
Project description:Desmoplastic and hypoxic pancreatic cancer microenvironment induces aberrant expression of miRNAs and hypoxia-inducible factor-1? (HIF-1?) responsible for gemcitabine (GEM) resistance. We demonstrated that miR-519c was down-regulated in pancreatic cancer and transfection of miR-519c in GEM-resistant pancreatic cancer cells inhibited HIF-1? level under hypoxia. We synthesized redox-sensitive mPEG-co-P(Asp)-g-DC-g-S-S-GEM polymer, with GEM payload of 14% (w/w) and 90% GEM release upon incubation with l-glutathione. We synthesized mPEG-co-P(Asp)-g-TEPA-g-DC for complex formation with miRNA. Chemical modification of miR-519c with 2'-O-methyl phosphorothioate (OMe-PS) at 3' end enhanced its stability and activity without being immunogenic. Epidermal growth factor receptor targeting peptide GE11 decoration increased tumor accumulation of micelles after systemic administration and significantly inhibited orthotopic desmoplastic pancreatic cancer growth in NSG mice by down-regulating HIF-1? and genes responsible for glucose uptake and cancer cell metabolism. Our multifunctional nanomedicine of GEM and OMe-PS-miR-519c offers a novel therapeutic strategy to treat desmoplasia and hypoxia-induced chemoresistance in pancreatic cancer.
Project description:Pancreatic ductal adenocarcinoma (PDAC) is among the most devastating human malignancies. The poor clinical outcome in PDAC is partly attributed to a growth-permissive tumor microenvironment. In the PDAC microenvironment, the stroma is characterized by the development of extensive fibrosis, with stromal components outnumbering pancreatic cancer cells. Each of the components within the stroma has a distinct role in conferring chemoresistance to PDAC, and intrinsic chemoresistance has further worsened this pessimistic prognosis. The nucleoside analog gemcitabine (GEM) is usually the recommended first-line chemotherapeutic agent for PDAC patients and is given alone or in combination with other agents. The mechanisms of intrinsic resistance to GEM are an active area of ongoing research. This review highlights the important role the complex structure of stroma in PDAC plays in the intrinsic resistance to GEM and discusses whether antistroma therapy improves the efficacy of GEM. The addition of antistroma therapy combined with GEM is expected to be a novel therapeutic strategy with significant survival benefits for PDAC patients.
Project description:Pancreatic cancer is one of the deadliest causes of cancer-related death in the United States, with a 5-year overall survival rate of 6 to 8%. These statistics suggest that immediate medical attention is needed. Gemcitabine (GEM) is the gold standard first-line single chemotherapy agent for pancreatic cancer but, after a few months, cells develop chemoresistance. Multiple clinical and experimental investigations have demonstrated that a combination or co-administration of other drugs as chemotherapies with GEM lead to superior therapeutic benefits. However, such combination therapies often induce severe systemic toxicities. Thus, developing strategies to deliver a combination of chemotherapeutic agents more securely to patients is needed. Nanoparticle-mediated delivery can offer to load a cocktail of drugs, increase stability and availability, on-demand and tumor-specific delivery while minimizing chemotherapy-associated adverse effects. This review discusses the available drugs being co-administered with GEM and the limitations associated during the process of co-administration. This review also helps in providing knowledge of the significant number of delivery platforms being used to overcome problems related to gemcitabine-based co-delivery of other chemotherapeutic drugs, thereby focusing on how nanocarriers have been fabricated, considering the modes of action, targeting receptors, pharmacology of chemo drugs incorporated with GEM, and the differences in the physiological environment where the targeting is to be done. This review also documents the focus on novel mucin-targeted nanotechnology which is under development for pancreatic cancer therapy.
Project description:High mortality in pancreatic cancer patients is partly due to resistance to chemotherapy. We describe that human pancreatic cancer cells acquire drug resistance by a novel mechanism in which they expel and remove chemotherapeutic drugs from the microenvironment via microvesicles (MVs). Using human pancreatic cancer cells that exhibit varied sensitivity to gemcitabine (GEM), we show that GEM exposure triggers the cancer cells to release MVs in an amount that correlates with that cell line's sensitivity to GEM. The importance of MV-release in gaining drug resistance in GEM-resistant pancreatic cancer cells was confirmed when the inhibition of MV-release sensitized the cells to GEM treatment, both in vitro and in vivo. Mechanistically, MVs remove drugs that are internalized into the cells and that are in the microenvironment. The differences between the drug-resistant and drug-sensitive pancreatic cancer cell lines tested here are explained based on the variable content of influx/efflux proteins present on MVs, which directly dictates the ability of MVs either to trap GEM or to allow GEM to flow back to the microenvironment.
Project description:BACKGROUND: One of the major reasons for poor prognosis of pancreatic cancer is its high resistance to currently available chemotherapeutic agents. In recent years, focal adhesion kinase (FAK), a central molecule in extracellular matrix (ECM)/integrin-mediated signaling, has been thought to be a key determinant of chemoresistance in cancer cells. In this study, we aimed to determine the roles of FAK phosphorylation in the intrinsic chemoresistance of pancreatic cancer cell lines. RESULTS: Our results showed that, the level of constitutive phosphorylation of FAK at Tyr397 correlated with the extent of intrinsic resistance to Gemcitabine (Gem) in four pancreatic cancer cell lines. Moreover, in Panc-1 cells, which had high expression of pFAK, specific inhibition of constitutive FAK phosphorylation by either RNAi or FRNK overexpression decreased the phosphorylation of Akt, reduced the levels of survivin expression and Bad phosphorylation at Ser136 and increased Gem-induced cytotoxicity and apoptosis. However, in AsPC-1 cells with a low level of pFAK, neither FAK RNAi nor FRNK overexpression affected Gem-induced cell apoptosis. We further found that laminin (LN) induced FAK and Akt phosphorylation in a time-dependent manner, increased the levels of survivin and pBad (pS136) and decreased Gem-induced cytotoxicity and apoptosis in AsPC-1 cells; Specific inhibition of LN-induced FAK phosphorylation by either FAK RNAi or FRNK overexpression suppressed the effects of LN on AsPC-1 cells. Moreover, inhibition of constitutive FAK phosphorylation in Panc-1 cells and LN-induced FAK phosphorylation in AsPC-1 cells by a novel and more specific FAK phosphorylation inhibitor PF-573,228 showed similar results with those of FAK phosphorylation inhibition by FAK RNAi or FRNK overexpression. CONCLUSIONS: In conclusion, our research demonstrates for the first time that both constitutive and LN-induced FAK phosphorylation contribute to increased intrinsic chemoresistance to Gem in pancreatic cancer cell lines and these effects are partly due to the regulation of Akt and Bad phosphorylation and survivin expression. Development of selective FAK phosphorylation inhibitors may be a promising way to enhance chemosensitivity in pancreatic cancer.