LIN28B-mediated PI3K/AKT pathway activation promotes metastasis in colorectal cancer models
Alice E. Shin, Kensuke Sugiura, Secunda W. Kariuki, David A. Cohen, Samuel P. Flashner, Andres J. Klein-Szanto, Noriyuki Nishiwaki, Dechokyab De, Neil Vasan, Joel T. Gabre, Christopher J. Lengner, Peter A. Sims, Anil K. Rustgi
Alice E. Shin, Kensuke Sugiura, Secunda W. Kariuki, David A. Cohen, Samuel P. Flashner, Andres J. Klein-Szanto, Noriyuki Nishiwaki, Dechokyab De, Neil Vasan, Joel T. Gabre, Christopher J. Lengner, Peter A. Sims, Anil K. Rustgi
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Research Article Gastroenterology Oncology

LIN28B-mediated PI3K/AKT pathway activation promotes metastasis in colorectal cancer models

Abstract

Colorectal cancer (CRC) remains a leading cause of cancer death because of metastatic spread. LIN28B is overexpressed in 30% of CRCs and promotes metastasis, yet its mechanisms remain unclear. In this study, we genetically modified CRC cell lines to overexpress LIN28B, resulting in enhanced PI3K/AKT pathway activation and liver metastasis in mice. We developed genetically modified mouse models with constitutively active Pik3ca that form intestinal tumors progressing to liver metastases with an intact immune system, addressing the limitations of previous Pik3ca-mutant models, including long tumor latency, mixed histology, and lack of distant metastases. The PI3Kα-specific inhibitor alpelisib reduced migration and invasion in vitro and metastasis in vivo. We present a comprehensive analysis of vertical inhibition of the PI3K/AKT pathway in CRC using the FDA-approved drugs alpelisib and capivasertib (an AKT inhibitor) in combination with LY2584702 (a ribosomal protein S6 kinase inhibitor) in CRC cell lines and mouse- and patient-derived organoids. Tissue microarrays from patients with CRC verified that LIN28B and PI3K/AKT pathway activation correlate with CRC progression. These findings highlight the critical role of the LIN28B-mediated PI3K/AKT pathway in CRC metastasis, the therapeutic potential of targeted inhibition, and the promise of patient-derived organoids in precision medicine in metastatic CRC.

Authors

Alice E. Shin, Kensuke Sugiura, Secunda W. Kariuki, David A. Cohen, Samuel P. Flashner, Andres J. Klein-Szanto, Noriyuki Nishiwaki, Dechokyab De, Neil Vasan, Joel T. Gabre, Christopher J. Lengner, Peter A. Sims, Anil K. Rustgi

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Figure 4

Alpelisib impairs LIN28B-induced cell migration and invasion and inhibits PI3Kα-induced organoid growth.

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Alpelisib impairs LIN28B-induced cell migration and invasion and inhibit...
(A) Western blot analysis of p-AKT (Ser473) and t-AKT in CRC cells (1-way ANOVA, mean ± SEM). (B) Colony formation assay of LIN28Bhi CRC cells treated with 5 μM alpelisib. Scale bars: 500 μm (1-way ANOVA, mean ± SEM). (C) Wound healing assay showing cell migration of CRC cells treated with 5 μM alpelisib at 0 hours. Scale bars: 500 μm (n = 4; 2-way ANOVA, mean ± SEM). (D) Transwell ECM invasion assay of CRC cells treated with 5 or 10 μM alpelisib. Scale bars: 1 mm (1-way ANOVA, mean ± SEM). (E) Representative bright-field images of colonic organoids derived from VilCre mice treated with 5 μM alpelisib every 2 days for 5 days. Scale bars: 500 μm. (F) Western blot analysis of LIN28B, p-AKT (Ser473), and t-AKT in colonic organoids derived from VilCre mice treated with 5 μM alpelisib (2-tailed Student’s unpaired t test within each group, mean ± SEM). (G) Quantification of growth of colonic organoids derived from VilCre mice treated with 5 μM alpelisib (n = 3–5; 2-way ANOVA, mean ± SEM; significance for day 5 is shown with asterisks; the asterisk above the data point signifies significance when compared with the R26WT/WT control group). *P < 0.05, **P < 0.01, ***P < 0.001.