MicroRNA-485-5p targets keratin 17 to regulate oral cancer stemness and chemoresistance via the integrin/FAK/Src/ERK/β-catenin pathway

Abstract

Background The development of drug resistance in oral squamous cell carcinoma (OSCC) that frequently leads to recurrence and metastasis after initial treatment remains an unresolved challenge. Presence of cancer stem cells (CSCs) has been increasingly reported to be a critical contributing factor in drug resistance, tumor recurrence and metastasis. Thus, unveiling of mechanisms regulating CSCs and potential targets for developing their inhibitors will be instrumental for improving OSCC therapy. Methods siRNA, shRNA and miRNA that specifically target keratin 17 (KRT17) were used for modulation of gene expression and functional analyses. Sphere-formation and invasion/migration assays were utilized to assess cancer cell stemness and epithelial mesenchymal transition (EMT) properties, respectively. Duolink proximity ligation assay (PLA) was used to examine molecular proximity between KRT17 and plectin, which is a large protein that binds cytoskeleton components. Cell proliferation assay was employed to evaluate growth rates and viability of oral cancer cells treated with cisplatin, carboplatin or dasatinib. Xenograft mouse tumor model was used to evaluate the effect of KRT17- knockdown in OSCC cells on tumor growth and drug sensitization. Results Significantly elevated expression of KRT17 in highly invasive OSCC cell lines and advanced tumor specimens were observed and high KRT17 expression was correlated with poor overall survival. KRT17 gene silencing in OSCC cells attenuated their stemness properties including markedly reduced sphere forming ability and expression of stemness and EMT markers. We identified a novel signaling cascade orchestrated by KRT17 where its association with plectin resulted in activation of integrin β4/α6, increased phosphorylation of FAK, Src and ERK, as well as stabilization and nuclear translocation of β-catenin. The activation of this signaling cascade was correlated with enhanced OSCC cancer stemness and elevated expression of CD44 and epidermal growth factor receptor (EGFR). We identified and demonstrated KRT17 to be a direct target of miRNA-485-5p. Ectopic expression of miRNA-485-5p inhibited OSCC sphere formation and caused sensitization of cancer cells towards cisplatin and carboplatin, which could be significantly rescued by KRT17 overexpression. Dasatinib treatment that inhibited KRT17-mediated Src activation also resulted in OSCC drug sensitization. In OSCC xenograft mouse model, KRT17 knockdown significantly inhibited tumor growth, and combinatorial treatment with cisplatin elicited a greater tumor inhibitory effect. Consistently, markedly reduced levels of integrin β4, active β-catenin, CD44 and EGFR were observed in the tumors induced by KRT17 knockdown OSCC cells. Conclusions A novel miRNA-485-5p/KRT17/integrin/FAK/Src/ERK/β-catenin signaling pathway is unveiled to modulate OSCC cancer stemness and drug resistance to the common first-line chemotherapeutics. This provides a potential new therapeutic strategy to inhibit OSCC stem cells and counter chemoresistance.

Functional and clinical characteristics of focal adhesion kinases in cancer progression

“…In studies related to the transformation of normal stem cells into tumor stem cells (CSCs) without genetic manipulation, fibroblast growth factor 2 (FGF2) was found to induce normal stem cells to acquire stemness expression of tumor stem cells and initiate cancer; this process was found to be associated with integrin/FAK/PI3K/AKT signaling pathway activation ( Sheta et al, 2021 ). In oral squamous cell carcinoma (OSCC), KRT17 regulates stemness marker levels via the integrin/FAK/Src/ERK/β-catenin pathway ( Jang et al, 2022 ). In addition to its contribution to the maintenance of tumor stemness, the effect of FAK on the stemness of embryonic stem cells has been identified by a wider range of researchers ( Baumann, 2021 ; Hur et al, 2021 ).…”

Integrin αM promotes macrophage alternative M2 polarization in hyperuricemia-related chronic kidney disease

“…Our finding indicated that Src participated in ITGAM/FAK signaling and might act as the downstream molecular. It's to be further explored whether Src together with FAK stimulates Akt1, or acts through other pathways, such as Stat3 and Erk (Bolos et al, 2010;Jang et al, 2022;Pan et al, 2019). β-catenin activation, as the canonical pathway of Wnt signaling, is associated with macrophage M2 polarization in tumor malignant behaviors and renal fibrosis (Feng et al, 2018;Yang et al, 2018).…”

Utilization of artificial intelligence-assisted histopathological detection in surveillance of oral squamous cell carcinoma staging: A narrative review

“…Keratin is a protein produced by keratinocytes in the epithelium and plays an important role in the protective function of epithelial tissue. Keratin interacts with integrins to maintain hemidesmosome stability so that cell adhesion is maintained and prevents cells from migrating [28,7]. In OSCC, the process of keratin formation is disrupted due to an increase in the keratin 8 (K8) and keratin 7 (K7) families resulting in excess keratinization activity.…”