ATG4B and pS383/392-ATG4B serve as potential biomarkers and therapeutic targets of colorectal cancer

Wan-Hsiang Hu; Ting-Ting Liu; Pei-Feng Liu; Paul Morgan; I-Ling Lin; Wei-Lun Tsai; Yi-Yun Cheng; Ang-Tsen Hsieh; Tsung-Hui Hu; Chih-Wen Shu

doi:10.1186/s12935-023-02909-7

ATG4B and pS383/392-ATG4B serve as potential biomarkers and therapeutic targets of colorectal cancer

Cancer Cell Int. 2023 Apr 10;23(1):63. doi: 10.1186/s12935-023-02909-7.

Authors

Wan-Hsiang Hu^#^{1

2}, Ting-Ting Liu^#³, Pei-Feng Liu^{4

5}, Paul Morgan⁶, I-Ling Lin^{7

8}, Wei-Lun Tsai⁹, Yi-Yun Cheng¹⁰, Ang-Tsen Hsieh¹¹, Tsung-Hui Hu¹², Chih-Wen Shu^{13

14}

Affiliations

¹ Department of Colorectal Surgery, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung, 83341, Taiwan.
² Graduate Institute of Clinical Medical Science, College of Medicine, Chang Gung University, Kaohsiung, 83341, Taiwan.
³ Department of Pathology, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung, 83341, Taiwan.
⁴ Department of Biomedical Science and Environmental Biology, Kaohsiung Medical University, Kaohsiung, 80708, Taiwan.
⁵ Institute of Biomedical Sciences, National Sun Yat-sen University, Kaohsiung, 80424, Taiwan.
⁶ Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA.
⁷ Department of Medical Laboratory Science and Biotechnology, Kaohsiung Medical University, Kaohsiung, 80708, Taiwan.
⁸ Department of Laboratory Medicine, Kaohsiung Medical University Hospital, Kaohsiung, 80708, Taiwan.
⁹ Department of Internal Medicine, Kaohsiung Veterans General Hospital, Kaohsiung, 81362, Taiwan.
¹⁰ Innovative Incubation Center, Praexisio Taiwain Inc, National Tsing Hua University, Hsinchu, 30013, Taiwan.
¹¹ Institute of Biopharmaceutical Sciences, National Sun Yat-sen University, No. 70, Lianhai Rd., Gushan Dist, Kaohsiung, 80424, Taiwan.
¹² Division of Hepato-Gastroenterology, Department of Internal Medicine, Kaohsiung Chang Gung Memorial Hospital, Chang Gung University College of Medicine, Kaohsiung, 83301, Taiwan.
¹³ Institute of Biopharmaceutical Sciences, National Sun Yat-sen University, No. 70, Lianhai Rd., Gushan Dist, Kaohsiung, 80424, Taiwan. cwshu@mail.nsysu.edu.tw.
¹⁴ Center of Excellence for Metabolic Associated Fatty Liver Disease, National Sun Yat-sen University, Kaohsiung, 80424, Taiwan. cwshu@mail.nsysu.edu.tw.

^# Contributed equally.

Abstract

Background: Autophagy related protease 4B (ATG4B) is a protease required for autophagy processing, which is strongly implicated in cancer progression. Phosphorylation of ATG4B is crucial for activation of its protease activity. However, little is known about the relationship of ATG4B and its phosphorylated form at Ser 383 and 392 sites (pS383/392-ATG4B), with clinical outcomes, particularly in colorectal cancer (CRC).

Methods: The ATG4B gene expression in CRC patients was obtained from The Cancer Genome Atlas (TCGA) database to analyze its clinical relevance. Tissue microarrays composed of 118 CRC patient specimens were used to determine the associations of ATG4B and pS383/392-ATG4B protein levels with prognosis. The biological functions of ATG4B in CRC cells were inspected with cell proliferation, mobility and spheroid culture assays.

Results: ATG4B gene expression was elevated in tumor tissues of CRC patients compared to that in adjacent normal tissues and high level of ATG4B expression was associated with poor survival. Similarly, protein levels of ATG4B and pS383/392-ATG4B were highly correlated with worse overall survival and disease-free survival. Stratification analysis results showed that high level of ATG4B had significantly higher risk of mortality in males and elderly patients compared to those female patients and patients 60 years or younger. In contrast, multivariate Cox's regression analysis indicated that high level of pS383/392-ATG4B was significantly linked to unfavorable overall survival and disease-free survival of males and elderly patients, whereas, it had no correlation with female patients and patients 60 years or younger. Moreover, high level of ATG4B was positively associated with increased mortality risk in patients with advanced AJCC stages (III and IV) and lymph node invasion (N1 and N2) for both overall survival and disease-free survival. Nevertheless, high level of pS383/392-ATG4B was positively correlated with increased mortality risk in patients with early AJCC stages (I and II) and without lymph node invasion (N0). In addition, silencing ATG4B attenuated migration, invasion, and further enhanced the cytotoxic effects of chemotherapeutic drugs in two and three-dimensional cultures of CRC cells.

Conclusions: Our results suggest that ATG4B and pS383/392-ATG4B might be suitable biomarkers and therapeutic targets for CRC.

Keywords: ATG4B; Phosphorylation; Prognosis; cancer.

Abstract

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