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WP1130 increases doxorubicin sensitivity in hepatocellular carcinoma cells through usp9x-dependent p53 degradation
Hao Liu1, Wei Chen1, Chao Liang1
1Department of Hepatobiliary and Pancreatic Surgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China.
Abstract:
Resistance to chemotherapeutic drugs is a major obstacle in hepatocellular carcinoma (HCC) therapy. However, the underlying mechanisms are not well understood. Recent evidence suggests that deubiquitinases (DUB) are key regulators in the mechanisms of cell proliferation, apoptosis and chemoresistance. The present study aimed to investigate whether WP1130, which inhibits activity of deubiquitinases, exerts synergistic cytotoxicity with doxorubicin in HCC and the underlying mechanisms. In the study, we found that Huh7, HepG2, and SNU387 HCC cells with p53 expression displayed enhanced response to the combination therapy compared with p53-deficient HCC cells (Hep3B) in the manner of inhibiting cell proliferation. Downregulation of p53 abolished the synergistic cytotoxicity of doxorubicin and WP1130 on HCC cells. Mechanistically, we found that combined treatment with WP1130 suppressed doxorubicin-mediated upregulation of p53 via promoting its ubiquitin-proteasome dependent degradation, whereas knockdown of DUB usp9x abolished this effect. Taken together, these results demonstrate that combined treatment with WP1130 sensitized HCC cells to doxorubicin via usp9x-depedent p53 degradation.
Insights
WP1130 enhances doxorubicin effectiveness in hepatocellular carcinoma (HCC) by targeting deubiquitinases (DUBs). This combination therapy sensitizes HCC cells through a mechanism involving p53 degradation, particularly in p53-expressing cells.
Area of Science:
- Oncology
- Molecular Biology
- Biochemistry
Background:
- Chemotherapeutic drug resistance is a significant challenge in hepatocellular carcinoma (HCC) treatment.
- Deubiquitinases (DUBs) are increasingly recognized as critical regulators of cell proliferation, apoptosis, and chemoresistance.
- Understanding the precise mechanisms of chemoresistance in HCC is crucial for developing effective therapies.
Purpose of the Study:
- To investigate the synergistic cytotoxicity of WP1130, a deubiquitinase inhibitor, in combination with doxorubicin in HCC.
- To elucidate the underlying molecular mechanisms by which WP1130 and doxorubicin interact in HCC cells.
- To determine the role of p53 and deubiquitinases in the response to this combination therapy.
Main Methods:
- Utilized multiple HCC cell lines (Huh7, HepG2, SNU387, Hep3B) with varying p53 expression levels.
- Administered combination therapy of WP1130 and doxorubicin.
- Assessed cell proliferation and cytotoxicity.
- Investigated the role of p53 by p53 downregulation experiments.
- Examined the effect of USP9X knockdown on the synergistic cytotoxicity.
- Analyzed the ubiquitin-proteasome dependent degradation pathway of p53.
Main Results:
- HCC cells expressing p53 showed enhanced sensitivity to the combination of WP1130 and doxorubicin, with inhibited cell proliferation.
- p53-deficient HCC cells exhibited a diminished response to the combined treatment.
- Downregulation of p53 abrogated the synergistic cytotoxic effect of WP1130 and doxorubicin.
- WP1130 suppressed doxorubicin-induced p53 upregulation by promoting its degradation via the ubiquitin-proteasome pathway.
- Knockdown of deubiquitinase USP9X abolished the WP1130-mediated sensitization to doxorubicin.
Conclusions:
- Combined treatment with WP1130 sensitizes HCC cells to doxorubicin, particularly those with intact p53.
- The synergistic effect is mediated by USP9X-dependent degradation of p53, which is suppressed by doxorubicin.
- WP1130 represents a potential therapeutic agent to overcome doxorubicin resistance in HCC by modulating p53 stability.
