Ubiquitin-Specific Peptidase 22 Contributes to Colorectal Cancer Stemness and Chemoresistance via Wnt/β-Catenin Pathway

Abstract

Background/Aims: Two major barriers to the successful treatment of colorectal cancer (CRC) are the development of stem cell-like characteristics (stemness) and chemoresistance. Ubiquitin-specific peptidase 22 (USP22) is a deubiquitinating enzyme and putative CRC marker that has emerged as a potential cause of both phenomena in CRC. There is evidence that USP22 acts through the Wnt/β-catenin pathway and that downregulation of the latter may reduce chemoresistance. Methods: In this study, we used CRC tissue specimens from human patients as well as human CRC cell lines to evaluate the role of USP22 in CRC stemness and chemoresistance in vitro and in vivo. RT-PCR and western blot were used for gene expression analyses. Immunohistochemistry was performed for USP22 expression in clinical samples. CD133 levels were analyzed by flow cytometry. Sphere formation and MTT assays were used for self-renewal and proliferation analysis. Chemoresistance was evaluated by cell viability and sphere formation assays. Results: We found a significant increase of USP22 in recurrent CRC and chemoresistant CRC cells as compared to primary CRC and non-chemoresistant CRC cells, respectively. We then demonstrated that USP22 mediates CRC cell chemoresistance through the Wnt/β-catenin pathway and that reducing USP22 in CRC cells diminishes chemoresistance. Conclusions: Having established the crucial role of USP22 in CRC stemness and chemoresistance, this study suggests that USP22 may be an ideal genetic target in the treatment of chemoresistant CRC.

MiR‐30‐5p suppresses cell chemoresistance and stemness in colorectal cancer through USP22/Wnt/β‐catenin signaling axis

“…The 3'UTR of USP22 was predicted to be a binding site of miR‐30‐5p (Figure A). In our previous report, we found that USP22 plays an important role in CRC development . We therefore investigated whether USP22 is the target of miR‐30‐5p.…”

“…Previously, we demonstrated that USP22 maintains stemness in CRC stem cells . To evaluate the effects of miR‐30‐5p on CRC cell stemness, we isolated CD133 + Caco2 and HCT15 cells using microbeads .…”

“…GAPDH or snRNAU6 were used as an internal control. The primers were used as previously described . PCR conditions were: initial denaturation at 95°C for 2 minutes, followed by 30 cycles of amplification at 95°C for 30 seconds, 55°C for 45 seconds and 72°C for 1 minute, and a final extension at 72°C for 15 minutes.…”

“…In our previous study, we found that ubiquitin‐specific peptidase 22 (USP22) promotes CRC stemness and chemoresistance through the Wnt/β‐catenin signaling pathway. In the present study, after determining that miR‐30‐5p expression is reduced in CRC tissues and cell lines, we identified the 3'UTR of USP22 as a binding site of miR‐30‐5p.…”

LncRNA SPRY4‐IT1 regulates breast cancer cell stemness through competitively binding miR‐6882‐3p with TCF7L2

“…35 The Wnt/β-catenin signalling pathway promotes cell proliferation and stem cell self-renewal. 36 Activation of the Wnt/β-catenin signalling pathway maintains stemness of breast cancer cells. 37 Thus, TCF7L2 mediates cell proliferation and stemness of breast cancer cells via the Wnt/β-catenin signalling pathway.…”