Synergistic antitumor effect of interferon-ß with gemcitabine in interferon-α-non-responsive pancreatic cancer cells

Interferon (IFN)-? is reported to have more potent antitumor effects than IFN-α. The aim of this study was to compare the synergistic antitumor activity of both IFNs when combined with gemcitabine on cultured pancreatic cancer cells expressing various levels of IFN receptor. The growth-inhibitory effects of IFN-α and IFN-? in combination with gemcitabine on three human pancreatic cancer cell lines (BxPC-3, MIAPaCa-2, Panc-1) were evaluated by MTT assay and isobolographic analysis. We also correlated their growth-inhibitory effects with the expression status of type I IFN receptor type 2 (IFNAR2). Western blot analysis indicated strong expression of IFNAR2 in BxPC-3 and MIAPaCa-2, but weak expression in Panc-1. The growth-inhibitory effect of gemcitabine was enhanced synergistically by IFN-α in BxPC-3 and MIAPaCa-2, but not in Panc-1. IFN-? exhibited more potent synergistic growth-inhibitory effects with gemcitabine in BxPC-3 and MIAPaCa-2 compared to IFN-α, and also synergistic enhancement in Panc-1. In conclusion, our results indicated that the growth-inhibitory effect of IFN-? with gemcitabine was synergistic not only in pancreatic cancer cells with strong expression of IFNAR2, but also in those with weak expression of IFNAR2.     

In vitro Study of the Antagonistic Effect of Low-dose Liquiritigenin on Gemcitabine-induced Capillary Leak Syndrome in Pancreatic Adenocarcinoma via Inhibiting ROSMediated Signalling Pathways

Background: To investigate in-vitro antagonistic effect of low-dose liquiritigenin on gemcitabine-inducedcapillary leak syndrome (CLS) in pancreatic adenocarcinoma via inhibiting reactive oxygen species (ROS)-mediated signalling pathways. Materials and Methods: Human pancreatic adenocarcinoma Panc-1 cells andhuman umbilical vein endothelial cells (HUVECs) were pre-treated using low-dose liquiritigenin for 24 h, thenadded into gemcitabine and incubated for 48 h. Cell viability, apoptosis rate and ROS levels of Panc-1 cellsand HUVECs were respectively detected through methylthiazolyldiphenyl-tetrazoliumbromide (MTT) andflow cytometry. For HUVECs, transendothelial electrical resistance (TEER) and transcellular and paracellularleak were measured using transwell assays, then poly (ADP-ribose) polymerase 1 (PARP-1) and metal matrixproteinase-9 (MMP9) activity were assayed via kits, mRNA expressions of p53 and Rac-1 were determinedthrough quantitative polymerase chain reaction (qPCR); The expressions of intercellular adhesion molecule1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1) and PARP-1 were measured via western blotting.Results: Low-dose liquiritigenin exerted no effect on gemcitabine-induced changes of cell viability, apoptosis rateand ROS levels in Panc-1 cells, but for HUVECs, liquiritigenin (3 μM) could remarkably elevate gemcitabineinduceddecrease of cell viability, transepithelial electrical resistance (TEER), pro-MMP9 level and expressionof ICAM-1 and VCAM-1 (p<0.01). Meanwhile, it could also significantly decrease gemcitabine-induced increaseof transcellular and paracellular leak, ROS level, PARP-1 activity, Act-MMP9 level, mRNA expressions of p53and Rac-1, expression of PARP-1 and apoptosis rate (p<0.01). Conclusions: Low-dose liquiritigenin exertsan antagonistic effect on gemcitabine-induced leak across HUVECs via inhibiting ROS-mediated signallingpathways, but without affecting gemcitabine-induced Panc-1 cell apoptosis. Therefore, low-dose liquiritigeninmight be beneficial to prevent the occurrence of gemcitabine-induced CLS in pancreatic adenocarcinoma.     

miRNA-375对胰腺癌细胞Panc-1增殖和凋亡的影响

  目的  探讨miRNA-375的外源性表达对人胰腺癌细胞Panc-1增殖和凋亡的影响。   方法  将miRNA-375表达质粒或对照质粒转染Panc-1细胞, qRT-PCR方法检测miRNA-375在转染细胞中的表达水平, 细胞计数法、流式细胞术分别检测外源性miRNA-375表达后Panc-1细胞增殖、凋亡和周期的变化情况。   结果  miRNA-375表达质粒组与对照组比较, 其miRNA-375表达诱导性升高, 细胞增殖受到抑制, 细胞凋亡率增加, 细胞周期阻滞于G₀~G₁期。   结论  在胰腺癌细胞Panc-1中增加miRNA-375的表达, 可抑制细胞增殖, 促进细胞凋亡和细胞周期阻滞, miRNA-375在胰腺癌细胞Panc-1中可能发挥潜在的抑癌基因作用。      

Synergistic effects of acyclic retinoid and gemcitabine on growth inhibition in pancreatic cancer cells

Pancreatic cancer is a serious healthcare problem worldwide because of its high mortality. Gemcitabine, a DNA synthesis inhibitor, is the standard first-line treatment for advanced pancreatic cancer and is also expected as a key drug for the combination therapy of this malignancy. Retinoids, which are derivatives of vitamin A, exert anti-tumor effects in various types of human malignancies, including pancreatic cancer. This study examined whether combination therapy with gemcitabine and acyclic retinoid (ACR), a new synthetic retinoid, had enhanced anti-tumor efficacy in pancreatic cancer. ACR, 9-cis-retinoic acid and gemcitabine preferentially inhibited the growth of human pancreatic cancer cells (Panc-1 and KP-2) in comparison to PE normal human pancreatic epithelial cells. The combination of ACR plus gemcitabine synergistically inhibited the growth of Panc-1 cells. The combined treatment with these two agents also acted synergistically to induce apoptosis and to inhibit Ras activation in these cancer cells. In vivo, the combination therapy augmented tumor growth inhibition through the induction of apoptosis and inhibition of cell proliferation in tumor tissue. These results suggest that the combination of ACR plus gemcitabine may therefore be an effective regimen for the chemotherapy of pancreatic cancer.     

Dasatinib can enhance paclitaxel and gemcitabine inhibitory activity in human pancreatic cancer cells

SRC and its activated form, phospho-SRC (pSRC), are aberrantly activated in pancreatic cancer and SRC represents a potential target for pancreatic cancer therapy. In this paper, we examined the inhibitory effect of dasatinib, a potent SRC inhibitor in combination with paclitaxel or gemcitabine on human and murine pancreatic cancer cell lines. The results showed that p-SRC can be highly expressed in most human and mouse pancreatic cancer cell lines compared with normal human cell lines and can be induced by paclitaxel or gemcitabine in HPAC cells. Dasatinib can enhance the efficacy of paclitaxel or gemcitabine by reducing the cell viability and inhibiting the cell proliferation. Dasatinib with paclitaxel combination exhibits statistically greater inhibition of the cell migration ability than single agent alone, paclitaxel with gemcitabine or FOLFIRINOX (combination of fluorouracil, leucovorin, irinotecan, and oxaliplatin) in HAPC, PANC-1, and BXPC-3 human pancreatic cancer cell lines as well as 8–285 APR and 8–365 APR mouse pancreatic cancer cell lines. In addition, dasatinib with gemcitabine combination also showed statistically greater inhibition of cell migration than single agent alone, paclitaxel with gemcitabine, or FOLFIRINOX in HAPC, PANC-1 and 8–285 APR cells. The combination of dasatinib with paclitaxel or gemcitabine also showed greater inhibition of the colony formation ability of pancreatic cancer cells compared with single-agent monotherapy or FOLFIRINOX. Dasatinib with paclitaxel or gemcitabine combination also inhibits p-SRC, p-STAT3, p-AKT, and/or p-ERK in these pancreatic cancer cells. Therefore, our results support that combined dasatinib and paclitaxel or gemcitabine therapy may be a viable therapeutic approach for human pancreatic cancer.     

Enhancement of gemcitabine sensitivity in pancreatic cancer by co-regulation of dCK and p8 expression

The purpose of this study was to improve the gemcitabine sensitivity in pancreatic cancer by adenovirus-mediated co-regulation of dCK and p8 expression. Firstly, we analyzed the sensitivity of three human pancreatic tumor cell lines (Capan-2, Panc-1 and BxPc-3) to gemcitabine using MTT assays, and found Panc-1 to be relatively resistant to gemcitabine. Further, we investigated the expression of dCK and p8 in different pancreatic cancer cell lines using real-time PCR and Western blot analysis, and found that the expression levels of these two genes were related to the gemcitabine sensitivity of pancreatic cancer cells. We constructed recombinant adenovirus vectors, Ad-dCK and Ad-p8-siRNA, that overexpressed dCK and knocked down p8, respectively. Using MTT assays, we observed that combined infection using Ad-dCK and Ad-p8-siRNA in vitro led to a significant decrease in the gemcitabine IC50 with an increase in apoptosis and caspase-3 activity in Panc-1 cells, which are relatively resistant to gemcitabine. Furthermore, in established subcutaneous pancreatic cancer models in nude mice, the tumor inhibition was markedly enhanced accompanied by elevation of the apoptosis index after intratumoral injection of Ad-dCK and Ad-p8-siRNA on the basis of intraperitoneal gemcitabine chemotherapy. Taken together, the present findings suggest that, dCK and p8 may be the important factors in the regulation of gemcitabine sensitivity in pancreatic cancer cells. Moreover, co-regulation of the two factors achieved better effects than regulation of either one alone.     

Bcl-x(L) antisense oligonucleotides induce apoptosis and increase sensitivity of pancreatic cancer cells to gemcitabine.

Pancreatic cancer is one of the leading causes of cancer-related death in Western countries. Bcl-x(L) is an anti-apoptotic factor of the Bcl-2 family, which is overexpressed in pancreatic cancer and its presence correlates with shorter patient survival. In this study, sequence-specific antisense oligonucleotides targeting the coding region of Bcl-x(L) were designed to examine whether apoptosis could be induced and chemosensitivity could be increased in pancreatic cancer cells. Five pancreatic cancer cell lines, Panc-1, MIA-PaCa-2, Capan-1, ASPC-1 and T3M4, were treated with Bcl-x(L) sense or antisense oligonucleotides and gemcitabine and the cell viability was examined by the SRB method. Apoptosis was determined using DAPI staining. In all examined pancreatic cancer cells, Bcl-x(L) expression was reduced after transfection of the antisense oligonucleotides. Cell death analysis using DAPI staining revealed that antisense, but not sense oligonucleotides caused apoptotic cell death. Furthermore, Bcl-x(L) antisense oligonucleotides enhanced the cytotoxic effects of gemcitabine in pancreatic cancer cells. Our results indicate that Bcl-x(L) antisense oligonucleotides effectively inhibited pancreatic cancer cell growth and caused apoptosis by reducing Bcl-x(L) protein levels. Bcl-x(L) antisense oligonucleotides also increased the chemosensitivity of pancreatic cancer cells, suggesting that Bcl-x(L) antisense therapy might be a potential future approach in this disease.     

Knockdown of clusterin sensitizes pancreatic cancer cells to gemcitabine chemotherapy by ERK1/2 inactivation

ABSTRACT: ObjectivesTo study the hypothesis that gemcitabine treatment augments the chemoresistance to gemcitabine by clusterin(sCLU) upregulation. Clusterin inhibition could augment the chemosensitivity of human pancreatic cancer cells by inhibition of clusterin-dependent pERK1/2 activation. METHODS: Clusterin was silenced by serial concentration of OGX-011 transfection in pancreatic cancer MIAPaCa-2 and BxPC-3 cell lines, then treated with serial concentration of gemcitabine. After the cells were treated with OGX-011 for 8 h,the cells were then treated with 5 muM ERK inhibitor PD98059 for 18 h or transfected with a wt-pERK-expressing plasmid into these cells for 24 h, after which the cells were treated with 1.0 uM gemcitabine for 24--72 h. Cell proliferation was determined by MTT. Apoptosis was quantified by flow cytometry,.sCLU and pERK1/2 production was analyzed by western blot,and sCLU mRNA was analyzed by RT-PCR. Xenograft of established tumors was used to evaluate primary tumor growth and apoptosis after treatment with gemcitabine alone or in combination with OGX-011. Phosphorylated ERK1/2 and sCLU levels in tumor tissues were measured by TUNEL analysis. RESULTS: As detected by MTT and FACS assay, a combination of gemcitabine + OGX-011 reflected the chemotherapeutic sensitivity and increased the gemcitabine -induced apoptosis in MIAPaCa-2 and BxPC-3 cells. Western blotting and RT-PCR analysis revealed that the expression of clusterin was higher in gemcitabine -resistant MIAPaCa-2 cells, however, decreased significantly after pretreatment with OGX-011. Furthermore, the OGX-011 or combination of gemcitabine + OGX-011 decreased the gemcitabine -induced activation of pERK1/2. wt-pERK-re-expression decreased OGX-011+ gemcitabine -induced apoptosis. Finally, OGX-011 in combination with gemcitabine substantially decreased the in vivo tumor growth and promoted apoptosis. Taken together, clusterin confers gmcitabine resistance in pancreatic cancer cells. CONCLUSIONS: Knockdown of clusterin by OGX-011 transfection sensitizes pancreatic cancer cells to gemcitabine by inhibition of gemcitabine -induced clusterin-pERK1/2 activation.     

Down-regulation of prostaglandin E2 by curcumin is correlated with inhibition of cell growth and induction of apoptosis in human colon carcinoma cell lines

Several in vitro and in vivo studies have demonstrated an association between curcumin, a diferuloylmethane derived from the plant Curcuma longa, and colorectal cancer (CRC) prevention. Nevertheless, the molecular mechanism responsible for the chemopreventive effect of curcumin is not well understood and most probably involves several pathways. Several studies indicate that curcumin may exert its effect by specifically inhibiting the cyclooxygenase-2 (COX-2) isoenzyme, which is up-regulated in 40 to 50% of colorectal polyps and in up to 85% of CRCs. However, other studies have suggested that curcumin may also inhibit polyps formation by COX-2 independent mechanisms (eg, inhibition of ErbB-1, AkT). The aim of this study was to evaluate whether curcumin's effect on the inhibition of cell growth and induction of apoptosis in human colon carcinoma cell lines is correlated with inhibition of PGE2 synthesis and down-regulation of COX-2. HT29 cells (expressing COX-2) and SW480 (deficient of COX-2) were exposed to different concentrations (0-50 microM) of curcumin for 72 hours. Growth inhibition was assessed by Coulter counter. Cell viability was assessed by the ability of metabolically active cells to reduce tetrazolium salt to colored formazan compounds (tetrazolium salt assay). Apoptosis was measured by two independent methods: flow cyto-metric analysis and 4'-6-Diamidino-2-phenylindole (DAPI) staining. Activity of COX-2 was evaluated by measuring prostaglandin E2 (PGE2) concentration using a specific enzyme-linked immunoassay. COX-1 and COX-2 expressions were measured by Western blot analysis. There was a significant difference between curcumin effect on COX-2-expressing (HT29: inhibitory concentration 50% [IC50] = 15 microM) and COX-2-deficient (SW480: IC50 = 40 microM) cells. Similarly, induction of apoptosis was higher in cells expressing COX-2. Western blot analysis and PGE2 immunoassay showed that curcumin inhibited COX-2 protein activity and expression in a dose-dependent manner. In conclusion, inhibition of cell survival and induction of apoptosis by curcumin in colorectal adenocarcinoma cell lines is associated with the inhibition of PGE2 synthesis and down-regulation of COX-2.     

Effects of gemcitabine on APE/ref-1 endonuclease activity in pancreatic cancer cells, and the therapeutic potential of antisense oligonucleotides

Apurinic/apyrimidinic endonuclease (APE) is a key enzyme involved in DNA base excision repair (BER) that is often expressed at elevated levels in human cancers. Pancreatic cancer cells treated with the nucleoside analogue gemcitabine (2', 2'-difluoro-2'deoxycytidine) showed increases in APE/redox effector factor (ref-1) protein levels (approximately two-fold for Panc-1 and six-fold for MiaPaCa-2), with corresponding increases in endonuclease activity. These results suggested that the activation of APE/ref-1 might be an adaptive response that contributes to gemcitabine resistance by facilitating BER. To test this hypothesis, we examined the effects of disrupting APE/ref-1 using antisense on gemcitabine toxicity. Antisense oligonucleotides decreased protein levels three-fold in MiaPaCa-2 and five-fold in Panc-1 in comparison to controls, associated with reduced endonuclease activity. Combination treatments with antisense oligonucleotides and gemcitabine partially suppressed the increase in APE/ref-1 activity seen in cells exposed to gemcitabine alone. While clonogenic assays showed only slight decreases in colony formation in cells treated with either antisense oligonucleotides or gemcitabine alone, the combination with APE/ref-1 antisense resulted in a 2-log enhancement of gemcitabine toxicity in Panc-1 cells. Overall these findings suggest that APE/ref-1 plays a significant role in gemcitabine resistance in some pancreatic cancer cells, and support the further investigation of novel treatments that target this protein.     

Thymosinalpha1 stimulates cell proliferation by activating ERK1/2, JNK, and increasing cytokine secretion in human pancreatic cancer cells

In this study, we investigated the expression and function of thymosinalpha1 (Thyalpha1) in human pancreatic cancer. We found that human pancreatic cancer cell lines Panc-1, Panc03.27, ASPC-1, and PL45 cells significantly over-expressed the mRNA of Thyalpha1 as compared to the normal human pancreatic ductal epithelium (HPDE) cells.. Thyalpha1 mRNA and protein levels were also over-expressed in clinical pancreatic adenocarcinoma specimens. In addition, synthetic Thyalpha1 significantly promoted Panc-1 cell proliferation and increased phosphorylation of ERK1/2 and JNK. Furthermore, Thyalpha1 increased the secretion of multiple cytokines including IL-10, IL-13, and IL-17 in Panc-1 cells. Thus, Thyalpha1 may have a new role in pancreatic cancer pathogenesis.     

PD98059抑制MAPK/ERK信号通路对胃癌细胞生物学功能的影响

目的：研究MAPK/ERK信号通路中关键信号分子MEK和ERK在胃癌SGC-7901细胞中的表达及PD98059抑制MAPK/ERK通路对胃癌细胞生物学功能的影响。方法：体外培养胃癌细胞株SGC-7901,不同浓度（0、25、50、100、200、300和400 mmol/L）PD98059处理24 h后CCK-8法检测细胞增殖率变化;再用0、25、50和100 μmol/L PD98059处理24 h后采用实时荧光定量PCR（qPCR）检测MEK和ERK mRNA的表达量;Western blot检测MEK和ERK蛋白的表达;流式细胞术检测细胞周期和凋亡变化。同时设正常胃黏膜上皮GES-1细胞为对照。结果：与正常胃黏膜上皮GES-1细胞相比,胃癌SGC-7901细胞中MEK和ERK mRNA的表达升高,差异具有统计学意义（P < 0.05）;p-MEK、p-ERK蛋白的表达亦显著升高,差异具有统计学意义（P < 0.05）。0~200 μmol/L PD98059处理SGC-7901细胞后,细胞增殖率随着抑制剂浓度的升高而降低（P < 0.05）。当PD98059浓度处于200~400 μmol/L时抑制作用逐渐趋于平稳。0~100 μmol/L PD98059作用后MEK、ERK mRNA的表达量低于对照组（P < 0.05）,随着PD98059浓度升高,ERK mRNA表达量逐渐降低（P < 0.05）。Western blot检测结果显示50和100 μmol/L PD98059作用后p-MEK1/2、p-ERK1/2蛋白表达降低（P < 0.05）。且抑制剂PD98059使胃癌SGC-7901细胞发生G0/G1期阻滞,可诱导细胞凋亡。结论：MAPK/ERK信号通路在胃癌细胞中激活,PD98059通过抑制MAPK/ERK信号通路的活性可影响胃癌细胞的生物学功能。     

Gemcitabine combined with docetaxel for the treatment of unresectable pancreatic carcinoma

Purpose. To assess the efficacy and toxicity of combination therapy with gemcitabine and docetaxel in patients with unresectable pancreatic carcinoma. Patients and Methods. Thirty-four patients with unresectable stage III, IVA, and IVB pancreatic carcinoma were eligible for this study. The first 18 patients received gemcitabine 800 mg/m² intravenously (IV) on days 1, 8, and 15 and docetaxel 75 mg/m² IV on day 1, repeated every 28 days. Due to a high incidence of myelosuppression in this first group, the treatment schedule was modified in the remaining patients to gemcitabine 1,000 mg/m² IV and docetaxel 40 mg/m² IV on days 1 and 8 of a 21-day schedule. The primary study endpoints were objective response rate and duration of survival. Results. Ten of 33 evaluable patients achieved a partial response, for an overall response rate of 30.3% (95% CI, 16.21%-48.87%). Partial responses noted in the pancreas and a variety of metastatic sites were maintained for 4 to 12 months (median 6 months). Twelve additional patients (36%) experienced stable disease. The median time to progression was 6 months, and median survival was 10.5 months. The toxicity profile of the modified gemcitabine/docetaxel schedule was more favorable than that associated with the initial regimen, particularly with respect to hematologic toxicity. Conclusion. The response and survival data reported here for combination therapy with gemcitabine and docetaxel are encouraging given the poor prognosis associated with unresectable pancreatic cancer. These data suggest that gemcitabine plus docetaxel may be more effective than either agent alone in the treatment of pancreatic cancer and warrants further study.     

Pancreatic carcinoma cells express neuropilins and vascular endothelial growth factor, but not vascular endothelial growth factor receptors

BACKGROUND: Neuropilins (NRPs) are characterized as coreceptors of vascular endothelial growth factor (VEGF). In the current study, the authors assessed the expression of NRPs, VEGF, and vascular endothelial growth factor receptors (VEGFRs), as well as VEGF-induced cell proliferation, in pancreatic carcinoma cell lines and tissue specimens. METHODS: Human pancreatic carcinoma cell lines (Panc-1 and MIA PaCa-2), normal human pancreatic ductal epithelial cells (HPDE), and human umbilical vein endothelial cells (HUVECs) were cultured. Human pancreatic adenocarcinoma tissue specimens were also studied. Expression levels of NRPs, VEGFRs, and VEGF were determined by real-time polymerase chain reaction analysis and immunostaining. Cell proliferation was examined using a [3H]thymidine incorporation assay. RESULTS: Both NRP-1 and NRP-2 were expressed in Panc-1 cells, HPDE cells, and HUVECs but were expressed minimally in MIA PaCa-2 cells. Panc-1 expressed 30 times more NRP-1 mRNA than NRP-2 mRNA. NRP-1 levels in Panc-1 cells were 5.3 times higher than in HPDE cells but were similar to NRP-1 levels in HUVECs. NRP-2 levels in Panc-1 cells were similar to NRP-2 levels in HPDE cells but lower than NRP-2 levels in HUVECs. Expression of all three VEGFRs was observed only in HUVECs. However, VEGF mRNA was detected in all cell types except for HUVECs. NRP-1 immunoreactivity levels were much higher than NRP-2 immunoreactivity levels in Panc-1 and human pancreatic adenocarcinoma tissue specimens, whereas VEGFRs were not detected in either of these two settings. In response to VEGF165, [3H]thymidine incorporation in Panc-1 cells increased significantly (by 61%; P < 0.01). A monoclonal antibody against human NRP-1 significantly blocked VEGF-induced cell proliferation in Panc-1 cells. CONCLUSIONS: The pancreatic carcinoma cell line Panc-1 and adenocarcinoma tissue specimens expressed high levels of NRP-1 and VEGF, but not VEGFRs, and exogenous VEGF significantly increased NRP-1-mediated, but not VEGFR-mediated, Panc-1 cell proliferation. These data suggested that NRP-1 may be involved in the pathogenesis of pancreatic carcinoma.     

CD147 silencing via RNA interference reduces tumor cell invasion, metastasis and increases chemosensitivity in pancreatic cancer cells

CD147, which belongs to the immunoglobulin superfamily, is a multifunctional glycoprotein that has been shown to increase tumor invasion, metastasis and multidrug resistance. To define the role of CD147 in invasion and metastasis more precisely, we utilized gene silencing to inhibit the expression of CD147 in pancreatic cancer cells. We observed that CD147 expression was significantly impeded at both the mRNA and protein levels and resulted in a decrease of MMP-2 and MMP-9 activities. There was also a decrease of MCT1 expression in the invasion and metastasis potential of pancreatic cancer cells, as well as increased chemosensitivity to gemcitabine in Panc-1 cells. Overall, these results suggest that CD147 plays an important role in the invasion, metastasis and chemosensitivity of the human pancreatic cancer cell line Panc-1, indicating that CD147 may be a promising therapeutic target for pancreatic cancer.     

A novel DDR1 inhibitor enhances the anticancer activity of gemcitabine in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is an extracellular matrix (ECM)-rich carcinoma, which promotes chemoresistance by inhibiting drug diffusion into the tumor. Discoidin domain receptor 1 (DDR1) increases tumor progression and drug resistance by binding to collagen, a major component of tumor ECM. Therefore, DDR1 inhibition may be helpful in cancer therapeutics by increasing drug delivery efficiency and improving drug sensitivity. In this study, we developed a novel DDR1 inhibitor, KI-301690 and investigated whether it could improve the anticancer activity of gemcitabine, a cytotoxic agent widely used for the treatment of pancreatic cancer. KI-301690 synergized with gemcitabine to suppress the growth of pancreatic cancer cells. Importantly, its combination significantly attenuated the expression of major tumor ECM components including collagen, fibronectin, and vimentin compared to gemcitabine alone. Additionally, this combination effectively decreased mitochondrial membrane potential (MMP), thereby inducing apoptosis. Further, the combination synergistically inhibited cell migration and invasion. The enhanced anticancer efficacy of the co-treatment could be explained by the inhibition of DDR1/PYK2/FAK signaling, which significantly reduced tumor growth in a pancreatic xenograft model. Our results demonstrate that KI-301690 can inhibit aberrant ECM expression by DDR1/PYK2/FAK signaling pathway blockade and attenuation of ECM-induced chemoresistance observed in desmoplastic pancreatic tumors, resulting in enhanced antitumor effect through effective induction of gemcitabine apoptosis.