Abstract 6222: Inhibition of 6-Phosphofructo-2-kinase (PFKFB3) induces cell death and synergistically enhances chemosensitivity in endometrial cancer
Authors: Xiao Yinan , Jin Ling , Bhattacharya Sayantani Sarkar , Staub Julie , Deng Chaolin , Fang Xiaoling , Shridhar Viji 
Published: September 2020

Objectives: Endometrial cancer (EC) is the most common gynecological cancer in the developed countries with rising incidence rates. However, the knowledge about targeted therapies that can improve response rates to chemotherapy in EC is limited. Of the cancer afflicting women, women with metabolic disorders such as diabetes and obesity have an increased risk of developing EC. 6-Phosphofructo-2-kinase/fructose-2,6-bisphosphatase 3 (PFKFB3), a glycolytic enzyme, is found to be highly expressed in many solid tumors. This study aimed to investigate the role and molecular mechanism of PFKFB3 in endometrial cancer.

Methods: HEC-1B and ARK-2 endometrial cancer cell lines were used as models to evaluate the potential antitumor effects of pharmacological (treatment with PFK158, a selective PFKFB3 inhibitor) and genetic (PFKFB3 knockdown using CRISPR/Cas9 technology) inhibition of PFKFB3 on EC. In vitro, we evaluated the effects of PFKFB3 inhibition, and its synergistic effects when combined with carboplatin (CBPt) or cisplatin on cell viability, glucose metabolism, autophagy, apoptosis, and changes of cell signaling using MTT and colony formation assays, Chou-Talalay methodology, immunofluorescence assay, flow cytometry and western blotting. In vivo, two EC subcutaneous xenograft models derived from HEC-1B and ARK-2 cell lines were used to investigate the effect of single-agent PFK158 and in combination with CBPt on tumor growth, followed by western blotting, TUNEL and immunohistochemistry staining of excised tumor tissue.

Results: Targeting PFKFB3 via PFK158 considerably reduced glucose uptake, ATP production, lactate release in EC cell lines. In vitro, inhibition of PFKFB3 induced cell death and synergistically enhanced CBPt/cisplatin sensitivity in EC cell lines by suppressing cell viability, inducing autophagy and apoptosis in a time- and dose-dependent manner. In vivo xenograft studies revealed that treatment with PFK158, either alone or in combination with CBPt, led to a marked reduction in tumor growth. In addition, PFK158 caused significant upregulation of cleaved PARP, cleaved caspase 3, and reduction of mTOR, Akt, ERK phosphorylation levels, both in vitro and in vivo.

Conclusions: Our results indicate that PFKFB3 plays a prominent role in the growth and chemoresistance in EC cells. Therefore, a selective PFKFB3 inhibitor or in combination with chemotherapy, may be used as a novel therapeutic strategy for patients with chemoresistant EC.

Citation Format: Yinan Xiao, Ling Jin, Sayantani Sarkar Bhattacharya, Julie Staub, Chaolin Deng, Xiaoling Fang, Viji Shridhar. Inhibition of 6-Phosphofructo-2-kinase (PFKFB3) induces cell death and synergistically enhances chemosensitivity in endometrial cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 6222.