Inhibiting 6-phosphogluconate dehydrogenase enhances chemotherapy efficacy in cervical cancer via AMPK-independent inhibition of RhoA and Rac1

Clin Transl Oncol. 2019 Apr;21(4):404-411. doi: 10.1007/s12094-018-1937-x. Epub 2018 Sep 4.

Abstract

Background: The oxidative pentose phosphate pathway (PPP) is essential for cancer metabolism and growth. However, the contribution of 6-phosphogluconate dehydrogenase (6PGD), a key enzyme of PPP, to cervical cancer development remains largely unknown.

Methods: mRNA and protein levels of 6PGD were analyzed in cervical cancer cells and tissues derived from patients and compared to normal counterparts. Using cell culture system and xenograft mouse model, the functions of 6PGD in cervical cancer are determined and its molecular mechanism is analyzed. 6PGD inhibitor physcion and siRNA knockdown were used.

Results: In this work, we demonstrate that 6PGD is aberrantly upregulated and activated in cervical cancer cells and patient tissues compared to normal counterparts. Using different approaches and preclinical models, we show that 6PGD inhibition decreases growth and migration, and enhances chemosensitivity in cervical cancer. Mechanistically, inhibition of 6PGD activates AMP-activated protein kinase (AMPK) and decreases RhoA and Rac1 activities. AMPK depletion significantly reduces the effects of 6PGD inhibition in decreasing RhoA and Rac1 activities, growth and migration in cervical cancer cells.

Conclusions: Our work is the first to demonstrate the aberrant expression of 6PGD and its predominant roles in cervical cancer cell growth and migration, via a AMPK-dependent activation. Our findings suggest 6PGD as a potential therapeutic target to enhance chemosensitivity in cervical cancer.

Keywords: 6PGD; AMPK; Cervical cancer; Physcion; Rac1; RhoA.

MeSH terms

  • AMP-Activated Protein Kinases / antagonists & inhibitors
  • AMP-Activated Protein Kinases / metabolism*
  • Animals
  • Apoptosis / drug effects
  • Biomarkers, Tumor / antagonists & inhibitors*
  • Biomarkers, Tumor / genetics
  • Biomarkers, Tumor / metabolism
  • Cell Movement / drug effects
  • Cell Proliferation / drug effects
  • Chemotherapy, Adjuvant
  • Emodin / analogs & derivatives
  • Emodin / pharmacology
  • Emodin / therapeutic use
  • Female
  • Gene Expression
  • Humans
  • Mice, SCID
  • Paclitaxel / pharmacology
  • Paclitaxel / therapeutic use
  • Phosphogluconate Dehydrogenase / antagonists & inhibitors*
  • Phosphogluconate Dehydrogenase / genetics
  • Phosphogluconate Dehydrogenase / metabolism
  • Tumor Cells, Cultured
  • Uterine Cervical Neoplasms / drug therapy*
  • Uterine Cervical Neoplasms / metabolism*
  • Uterine Cervical Neoplasms / pathology
  • Xenograft Model Antitumor Assays
  • rac1 GTP-Binding Protein / metabolism*
  • rhoA GTP-Binding Protein / metabolism*

Substances

  • Biomarkers, Tumor
  • Phosphogluconate Dehydrogenase
  • AMP-Activated Protein Kinases
  • rac1 GTP-Binding Protein
  • rhoA GTP-Binding Protein
  • physcione
  • Emodin
  • Paclitaxel