MutY-Homolog (MYH) inhibition reduces pancreatic cancer cell growth and increases chemosensitivity

Oncotarget. 2017 Feb 7;8(6):9216-9229. doi: 10.18632/oncotarget.13985.

Abstract

Patients with pancreatic ductal adenocarcinoma (PC) have a poor prognosis due to metastases and chemoresistance. PC is characterized by extensive fibrosis, which creates a hypoxic microenvironment, and leads to increased chemoresistance and intracellular oxidative stress. Thus, proteins that protect against oxidative stress are potential therapeutic targets for PC. A key protein that maintains genomic integrity against oxidative damage is MutY-Homolog (MYH). No prior studies have investigated the function of MYH in PC cells. Using siRNA, we showed that knockdown of MYH in PC cells 1) reduced PC cell proliferation and increased apoptosis; 2) further decreased PC cell growth in the presence of oxidative stress and chemotherapy agents (gemcitabine, paclitaxel and vincristine); 3) reduced PC cell metastatic potential; and 4) decreased PC tumor growth in a subcutaneous mouse model in vivo. The results from this study suggest MYH may be a novel therapeutic target for PC that could potentially improve patient outcome by reducing PC cell survival, increasing the efficacy of existing drugs and reducing metastatic spread.

Keywords: DNA repair; chemoresistance; mutY-homolog (MYH); oxidative stress; pancreatic cancer.

MeSH terms

  • Animals
  • Antineoplastic Agents / pharmacology*
  • Apoptosis / drug effects
  • Carcinoma, Pancreatic Ductal / drug therapy*
  • Carcinoma, Pancreatic Ductal / genetics
  • Carcinoma, Pancreatic Ductal / metabolism
  • Carcinoma, Pancreatic Ductal / pathology
  • Cell Cycle / drug effects
  • Cell Line, Tumor
  • Cell Proliferation / drug effects*
  • DNA Glycosylases / genetics
  • DNA Glycosylases / metabolism*
  • Deoxycytidine / analogs & derivatives
  • Deoxycytidine / pharmacology
  • Dose-Response Relationship, Drug
  • Female
  • Gemcitabine
  • Gene Expression Regulation, Neoplastic
  • Humans
  • Mice, Inbred BALB C
  • Mice, Nude
  • Oxidative Stress / drug effects
  • Paclitaxel / pharmacology
  • Pancreatic Neoplasms / drug therapy*
  • Pancreatic Neoplasms / genetics
  • Pancreatic Neoplasms / metabolism
  • Pancreatic Neoplasms / pathology
  • RNA Interference
  • Signal Transduction / drug effects
  • Time Factors
  • Transfection
  • Tumor Burden / drug effects
  • Tumor Hypoxia
  • Tumor Microenvironment
  • Vincristine / pharmacology
  • Xenograft Model Antitumor Assays

Substances

  • Antineoplastic Agents
  • Deoxycytidine
  • Vincristine
  • DNA Glycosylases
  • mutY adenine glycosylase
  • Paclitaxel
  • Gemcitabine