ORIGINAL RESEARCH article
Front. Immunol.
Sec. Cancer Immunity and Immunotherapy
Hsa-miR-99a deficiency contributes to MSI-H colorectal cancer progression by activating the mTOR pathway and inducing Th1/Th2 imbalance
Xuejing Yang
Tingting Zhang
Hu Sun
Huijing Feng
Dong Song
Shanxi Bethune Hospital, Shanxi Medical University, Taiyuan, China
Select one of your emails
You have multiple emails registered with Frontiers:
Notify me on publication
Please enter your email address:
If you already have an account, please login
You don't have a Frontiers account ? You can register here
Abstract
Background: Hsa-miR-99a has been linked to the advancement of several malignancies, including colorectal cancer (CRC). This investigation seeks to elucidate its function and regulatory network in CRC. Methods: Differential expression of hsa-miR-99a was analyzed between microsatellite stable (MSS) and microsatellite instability-high (MSI-H) subgroups. Potential target mRNAs of hsa-miR-99a were retrieved from TargetScan and miRWalk databases. Overlapping mRNAs were subjected to correlation analysis, with candidate genes selected based on |correlation coefficient| > 0.3 and p < 0.05. Enrichment analyses were performed, highlighting key pathways, particularly mTOR signaling. Immune infiltration profiles were compared between MSS and MSI-H groups. Correlation between hsa-miR-99a and mTOR pathway-related genes was validated by RT-qPCR and Western blot. Additionally, multiplex immunohistochemistry (mIHC) with tyramine signal amplification (TSA) was used to characterize the immune microenvironment in MSI-H CRC samples. Results: Hsa-miR-99a expression was significantly higher in MSS compared to MSI-H groups. Twelve key target genes were identified, including ATP2B2, ATP2B4, SLC8A1, KCNJ5, NTRK3, TNFRSF19, GHR, CXCL12, NTNG1, SDC2, SFRP1, and PRICKLE2. Immune infiltration analysis revealed significant differences in 24 cell types between MSS and MSI-H groups, including Th1, Th2, Th17, and effector memory CD8+ T cells. Ten mTOR pathway-related genes (ATP6V1G2, WNT2, WNT6, WNT9A, WNT9B, FZD1, FZD4, FZD8, IGF1, AKT3) exhibited strong correlation with hsa-miR-99a. Among these, ATP6V1G2 and WNT6 were upregulated in the MSI-H group. mIHC analysis indicated reduced Th1 but increased Th2 and Th17 biomarkers in MSI-H CRC. Conclusion: This study identified key genes and immune microenvironment alterations regulated by hsa-miR-99a in CRC, offering novel insights and potential therapeutic targets for CRC treatment.
Summary
Keywords
colorectal cancer, hsa-miR-99a, Immuneinfiltration, Microsatellite Instability, mTOR pathway
Received
26 January 2026
Accepted
20 February 2026
Copyright
© 2026 Yang, Zhang, Sun, Feng and Song. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
*Correspondence: Dong Song
Disclaimer
All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.