Mechanistic study on Tricellulin regulation of colorectal cancer cell invasion, metastasis and epithelial-mesenchymal transition

[Objectives] To investigate the related molecular mechanisms by which Tricellulin regulates the invasion, migration and metastasis and epithelial-mesenchymal transition (EMT) progression in colorectal cancer. [Methods] Tissue specimens from 40 colorectal cancer patients (cancerous and adjacent normal tissues) treated at The Second Affiliated Hospital of Guangxi Medical University between March 2019 and December 2023 were analyzed. Immunohistochemistry assessed Tricellulin expression, and its correlation with clinical-pathological features was evaluated. Stable Tricellulin-overexpressing and -knockdown colorectal cancer cell models (HCT116, HT-29) were validated via Western blotting and real-time fluorescence quantitative PCR. The experimental groups included: HCT116 knockdown group (HCT116-KD group) and its negative control (HCT116-NC- group), HCT116 overexpression group (HCT116-OE group) and its negative control(HCT116-NC+ group), HCT116 blank control group (wild-type HCT116 cells, designated as HCT116 group); HT-29 knockdown group (HT-29-KD group) and its negative control (HT-29-NC- group), HT-29 overexpression group (HT-29-OE group) and its negative control (HT-29-NC+ group), HT-29 blank control group (wild-type HT-29 cells, designated as HT-29 group). Cell migration assays evaluated colorectal cancer cells (HCT116) migratory effects, while Western blotting analyzed EMT markers and TGFβ/Smad pathway proteins. [Results] The positive expression rate of Tricellulin in colorectal cancer tissues was higher than that in adjacent normal tissues. Among the 40 colorectal cancer cases, Tricellulin was highly expressed in 30 cases (75%) in in cancer tissues and 3 cases (7.5%) in adjacent tissues (P<0.05). The expression of Tricellulin was not related to patients’ gender or age but was associated with lymph node metastasis, distant metastasis, and TNM staging in colorectal cancer patients (P<0.05). The results of real-time fluorescence quantitative PCR and Western blotting showed that the HCT116 and HT-29 cell models with stable low expression/overexpression of Tricellulin were successfully established. The number of migrating cells in the HCT116-KD group was less than that in the HCT116-NC- group (P<0.05), and the number of migrating cells in the HCT116-OE group was higher than that in the HCT116-NC+ group (P<0.05). The relative expression levels of TGFβ1, P-Smad3, and P-Smad2 proteins in the HCT116-NC- and HT-29-KD groups were lower than those in their respective control groups (P<0.05), while the relative expression levels of TGFβ1, P-Smad3, and P-Smad2 proteins in the HCT116-OE and HT-29-OE groups were higher than those in their respective control groups (P<0.05). [Conclusions] Tricellulin promotes colorectal cancer cell invasion, migration, and EMT progression potentially via TGFβ1/Smad signaling pathway activation.