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

Abstract

Abstract. The purpose of this study was to improve the gemcitabine sensitivity in pancreatic cancer by adenovirusmediated 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 IC 50 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.

Chemoresistance in Pancreatic Cancer

“…The obtained resistance of PDAC cell lines to gemcitabine suggests that dCK is often inactivated [37]. Knockdown of the dCK gene often leads to gemcitabine resistance [38], while overexpression of dCK can restore the chemosensitivity of gemcitabine in gemcitabine-resistant cell lines [39,40]. A large number of clinical studies have shown that the dCK expression level in pancreatic cancer tissue is a reliable prognostic indicator of PFS, so dCK may be the best biomarker of dFdC sensitivity for PC patients treated with gemcitabin [41,42].…”

Targeting the Stress-Induced Protein NUPR1 to Treat Pancreatic Adenocarcinoma

“…Indeed, NUPR1 has recently elicited significant attention due to its role in promoting cancer development and progression in pancreas [18,19]. NUPR1-dependent effects also mediate resistance to anticancer drugs [20,21,22]. Remarkably, we have previously shown that genetic inactivation of Nupr1 antagonizes the growth of pancreatic cancer [16,23], and other laboratories have also demonstrated that genetic inactivation of NUPR1 stops the growth of hepatocarcinoma [24], non-small lung cancer [25], cholangiocarcinoma [26], glioblastoma [27], multiple myeloma [28,29], and osteosarcoma [30], thereby supporting NUPR1 as a promising therapeutic target for the development of new therapies against cancers.…”

Overcoming nucleoside analog chemoresistance of pancreatic cancer: A therapeutic challenge

“…Overexpression of dCK was found to significantly enhance gemcitabine sensitivity in two of three pancreatic cancer cell lines [36]. Furthermore, simultaneous expression of dCK and p8 in a gemcitabine-resistant pancreatic cancer cell line, PANC-1, significantly decreased the cytotoxic IC 50 of gemcitabine and enhanced apoptosis and caspase-3 activity; tumor growth inhibition was also noticeably improved in nude mice [37]. Clinically, low immunohistochemical expression of dCK was correlated with both decreased overall survival as well as older age of patients, suggesting a role of age-related methylation in patients [38].…”

“…Tumor volume was reduced dramatically and mouse survival prolonged significantly due to an increase in apoptosis and decrease in cellular proliferation [103]. Recently, it has also been found that the overexpression of dCK and knockdown of p8 with recombinant adenoviral vectors also significantly decreased gemcitabine resistance in PANC-1 cells and inhibited tumor growth with enhanced apoptosis and caspase-3 activity [37]. …”