Nuclear HKII-P-p53 (Ser15) Interaction is a Prognostic Biomarker for Chemoresponsiveness and Glycolytic Regulation in Epithelial Ovarian Cancer.

Chae Young Han ,David Chan,Elizabeth Macdonald,Youngjin Han,Anne-Marie Mes-Masson,Zhen Lü ,Robin J Parks ,Barbara C Vanderhyden ,Annie Nga‐Yin Cheung ,Chul Lee ,Karen Kl Chan ,Jinho Lim ,David A Patten ,Se Ik Kim ,Li Jun Di ,Eurı́dice Carmona ,Hextan Ys Ngan ,Yong Sang Song ,Michelle K.y Siu ,Mary Ellen Harper ,Ja Lok Ku ,Robert C Bast ,Benjamin K Tsang

doi:10.3390/cancers13143399

Abstract

Simple SummaryHexokinase II (HKII) is a key glycolysis enzyme associated with tumorigenesis, but its molecular mechanism and pathophysiological role in chemoresistant ovarian cancer remain elusive. In this study, we delineate the novel mechanism showing that activated phosphorylated-p53 (P-p53 Ser15) is required for the regulation of HKII intracellular trafficking and metabolic regulation in chemosensitive ovarian cancer, but not in chemoresistant ovarian cancer harboring p53 mutation. We have observed that increased nuclear HKII-P-p53 (Ser15) interaction is likely associated with chemosensitivity and better survival outcomes in epithelial ovarian cell lines, human primary epithelial ovarian cancer cells, and tumor sections. Nuclear HKII-P-p53 (Ser15) interaction may function as a promising prognostic biomarker, enabling prediction of patients with poor prognosis for deciding better clinical strategies.In epithelial ovarian cancer (EOC), carboplatin/cisplatin-induced chemoresistance is a major hurdle to successful treatment. Aerobic glycolysis is a common characteristic of cancer. However, the role of glycolytic metabolism in chemoresistance and its impact on clinical outcomes in EOC are not clear. Here, we show a functional interaction between the key glycolytic enzyme hexokinase II (HKII) and activated P-p53 (Ser15) in the regulation of bioenergetics and chemosensitivity. Using translational approaches with proximity ligation assessment in cancer cells and human EOC tumor sections, we showed that nuclear HKII-P-p53 (Ser15) interaction is increased after chemotherapy, and functions as a determinant of chemoresponsiveness as a prognostic biomarker. We also demonstrated that p53 is required for the intracellular nuclear HKII trafficking in the control of glycolysis in EOC, associated with chemosensitivity. Mechanistically, cisplatin-induced P-p53 (Ser15) recruits HKII and apoptosis-inducing factor (AIF) in chemosensitive EOC cells, enabling their translocation from the mitochondria to the nucleus, eliciting AIF-induced apoptosis. Conversely, in p53-defective chemoresistant EOC cells, HKII and AIF are strongly bound in the mitochondria and, therefore, apoptosis is suppressed. Collectively, our findings implicate nuclear HKII-P-p53(Ser15) interaction in chemosensitivity and could provide an effective clinical strategy as a promising biomarker during platinum-based therapy.

Highlights

Carboplatin—a standard, first-line, platinum-based chemotherapy for epithelial ovarian cancer (EOC)—is an analogue of cisplatin (CDDP), which is often used in case of relapse [1,2]
Progression-free interval (PFI)—the duration from the termination of chemotherapy to relapse [2]—is frequently used as an indicator of chemoresponsiveness, and is generally defined by a 6-month (m) period: chemosensitivity (PFI > 6 m) and chemoresistance (PFI ≤ 6 m). Using this standard for chemoresponsiveness, we first performed a Proximity ligation assays (PLAs) assessment in EOC tumor sections (n = 41 pairs) of different histological subtypes (36 high-grade serous (HGS), 4 clear cell, and 1 endometrioid) obtained pre- and post-chemotherapy from the same EOC patients (Figure 1A,B), in order to determine whether nuclear localization of hexokinase II (HKII)-P-p53 (Ser15) interaction is associated with prognosis and chemoresponsiveness as determined by the length of progression-free interval [36,37] (Table S3)
When comparing the nuclear HKII-P-p53 (Ser15) interaction in post-chemotherapy relative to pre-chemotherapy sections, we observed a notable increase in nuclear HKII-P-p53 (Ser15) interaction in a chemosensitive cancer (PFI = 40 m) associated with longer PFI, but not in a chemoresistant cancer associated with shorter PFI (PFI = 1 m) (Figure 1C)

Summary

Introduction

Carboplatin—a standard, first-line, platinum-based chemotherapy for EOC—is an analogue of cisplatin (CDDP), which is often used in case of relapse [1,2]. 70% of EOC patients develop chemoresistance within 15 months, leading to poor 5-year overall survival (OS) rates (30–50%) [1]. TP53 is frequently mutated in EOC (>70%), especially in high-grade serous (HGS) histotypes—the most prevalent subtype (>90%) [5,6], often associated with chemoresistance. P53 encoded by TP53 is a key regulator of apoptosis, and is rapidly increased in response to DNA-damaging agents, such as CDDP [7]. Activation/stabilization of p53 occurs through its site-specific phosphorylation at Ser and Ser in response to CDDP [4]. P53 governs multiple cellular processes, including DNA repair, cell cycle, apoptosis, and cell metabolism [8,9]. We previously reported that p53 is critical for the induction of apoptosis in chemoresistant cells, even when metabolism is suppressed [10]

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