Pyrroline-5-Carboxylate Reductase-2 Promotes Colorectal Carcinogenesis by Modulating Microtubule-Associated Serine/Threonine Kinase-like/Wnt/β-Catenin Signaling

Authors

Raju Lama Tamang, University of Nebraska Medical Center
Balawant Kumar, University of Nebraska Medical CenterFollow
Sagar M. Patel, University of Nebraska - LincolnFollow
Ishwor Thapa, University of Nebraska at OmahaFollow
Alshomrani Ahmad, University of Nebraska Medical Center
Vikas Kumar, University of Nebraska Medical CenterFollow
Rizwan Ahmad, University of Nebraska Medical CenterFollow
Donald F. Becker, University of Nebraska-LincolnFollow
Dundy Kiran Bastola, University of Nebraska at OmahaFollow
Punita Dhawan, University of Nebraska Medical Center, Veterans Affairs Nebraska-Western Iowa Health Care SystemFollow
Amar B. Singh, University of Nebraska Medical Center, Veterans Affairs Nebraska-Western Iowa Health Care SystemFollow

Document Type

Article

Date of this Version

7-18-2023

Citation

Lama Tamang, R.; Kumar, B.; Patel, S.M.; Thapa, I.; Ahmad, A.; Kumar, V.; Ahmad, R.; Becker, D.F.; Bastola, D.; Dhawan, P.; et al. Pyrroline-5-Carboxylate Reductase-2 Promotes Colorectal Carcinogenesis by Modulating Microtubule-Associated Serine/ Threonine Kinase-like/Wnt/ β-Catenin Signaling. Cells 2023, 12, 1883. https://doi.org/10.3390/ cells12141883

Comments

Open access.

Abstract

Background: Despite significant progress in clinical management, colorectal cancer (CRC) remains the third most common cause of cancer-related deaths. A positive association between PYCR2 (pyrroline-5-carboxylate reductase-2), a terminal enzyme of proline metabolism, and CRC aggressiveness was recently reported. However, how PYCR2 promotes colon carcinogenesis remains ill understood. Methods: A comprehensive analysis was performed using publicly available cancer databases and CRC patient cohorts. Proteomics and biochemical evaluations were performed along with genetic manipulations and in vivo tumor growth assays to gain a mechanistic understanding. Results: PYCR2 expression was significantly upregulated in CRC and associated with poor patient survival, specifically among PYCR isoforms (PYCR1, 2, and 3). The genetic inhibition of PYCR2 inhibited the tumorigenic abilities of CRC cells and in vivo tumor growth. Coinciding with these observations was a significant decrease in cellular proline content. PYCR2 overexpression promoted the tumorigenic abilities of CRC cells. Proteomics (LC-MS/MS) analysis further demonstrated that PYCR2 loss of expression in CRC cells inhibits survival and cell cycle pathways. A subsequent biochemical analysis supported the causal role of PYCR2 in regulating CRC cell survival and the cell cycle, potentially by regulating the expression of MASTL, a cell-cycle-regulating protein upregulated in CRC. Further studies revealed that PYCR2 regulates Wnt/β-catenin-signaling in manners dependent on the expression of MASTL and the cancer stem cell niche. Conclusions: PYCR2 promotes MASTL/Wnt/β-catenin signaling that, in turn, promotes cancer stem cell populations and, thus, colon carcinogenesis. Taken together, our data highlight the significance of PYCR2 as a novel therapeutic target for effectively treating aggressive colon cancer.