Cancer-associated fibroblasts promote oral squamous cell carcinoma progression through LOX-mediated matrix stiffness

Abstract

Background Cancer-associated fibroblasts (CAFs), the most abundant cells in the tumor microenvironment, have prominent roles in the development of solid tumors as stromal targets. However, the underlying mechanism of CAFs’ function in oral squamous cell carcinoma (OSCC) development remains unclear. Here, we investigated the role of lysyl oxidase (LOX) expression in CAFs in tumor stromal remodeling and the mechanism of its effect on OSCC progression. Methods Multiple immunohistochemistry (IHC) staining was performed to detect the correlation of CAFs and LOX in the stroma of OSCC specimens, as well as the correlation with clinicopathological parameters and prognosis. The expression of LOX in CAFs were detected by RT-qPCR and western blot. The effects of LOX in CAFs on the biological characteristics of OSCC cell line were investigated using CCK-8, wound-healing and transwell assay. CAFs were co-cultured with type I collagen in vitro, and collagen contraction test, microstructure observation and rheometer were used to detect the effect of CAFs on remodeling collagen matrix. Then, collagen with different stiffness were established to investigate the effect of matrix stiffness on the progression of OSCC. Moreover, we used focal adhesion kinase (FAK) phosphorylation inhibitors to explored whether the increase in matrix stiffness promote the progression of OSCC through activating FAK phosphorylation pathway. Results LOX was colocalized with CAFs in the stroma of OSCC tissues, and its expression was significantly related to the degree of malignant differentiation and poor prognosis in OSCC. LOX was highly expressed in CAFs, and its knockdown impaired the proliferation, migration, invasion and EMT process of OSCC cells. The expression of LOX in CAFs can catalyze collagen crosslinking and increase matrix stiffness. Furthermore, CAFs-derived LOX-mediated increase in collagen stiffness induced morphological changes and promoted invasion and EMT process in OSCC cells by activating FAK phosphorylation pathway. Conclusions Our findings suggest that CAFs highly express LOX in the stroma of OSCC and can remodel the matrix collagen microenvironment, and the increase in matrix stiffness mediated by CAFs-derived LOX promotes OSCC development through FAK phosphorylation pathway. Thus, LOX may be a potential target for the early diagnosis and therapeutic treatment of OSCC.

Matrix stiffness induces an invasive-dormant subpopulation via cGAS-STING axis in oral cancer

“…Stiffness contributed to the EMT and migratory behavior of OSCC cells [17] . CAF‑derived LOX‑mediated increase in collagen stiffness induced morphological changes and promoted invasion and EMT in OSCC cells by activating focal adhesion kinase (FAK) pathway [15] . Although the ECM-derived cues have been proposed to regulate dormancy of disseminating tumor cells (DTCs) [1] , the relation between matrix stiffness and cancer-cell dormancy is largely obscure.…”

“…We previously described a dramatic increase of interstitial fibrosis and cancer-associated fibroblasts (CAFs) infiltration in the tongue cancer microenvironment, which correlated with patient's T stage [14] . Also, stiffened matrix was reported to regulate cell morphology, proliferation, and invasiveness in OSCC [15] , [16] , [17] . However, despite that primary-tumor stiffness was shown to correlate with recurrence and poor survival[ 10 , 18 , 19 ], whether and how it affects tumor-cell dormancy remained unclear.…”

The role of long noncoding RNAs as regulators of the epithelial–Mesenchymal transition process in oral squamous cell carcinoma cells

“…Tumor-associated macrophages (TAMs) with an M1 phenotype can drive EMT progression and promote cancer-stem cell (CSC) development in OSCC through the upregulation of MMP-14 and MME ( You et al, 2022 ). In OSCC, stromal CAFs express high levels of lysyl oxidase (LOX), which promotes matrix collagen remodeling and stiffens the matrix in a way that promotes OSCC progression via the FAK phosphorylation pathway ( Zhang et al, 2021 ). Hu et al (2022 ) determined that neutrophils can control EMT and JAK2/STAT3 signaling in OSCC via chemerin, thus promoting progression.…”

Identification and validation of roles of lysyl oxidases in the predictions of prognosis, chemotherapy and immunotherapy in glioma

“…For example, up-regulation of LOX is previously reported to trigger excessive collagen deposition and subsequently enhance cancer cell proliferation and invasiveness in Lkb1 -deficient lung tumors ( Gao et al, 2010 ). Besides, high LOX expression in the cancer-associated fibroblasts can also remodel the matrix collagen microenvironment and increase matrix stiffness and finally promote oral squamous cell carcinoma progression ( Zhang et al, 2021 ). In glioma research, the increase of LOX protein expression is positively associated with the malignant grade of astrocytomas and GBM with IDH1 mutation always exhibits lower LOX expression levels ( da Silva et al, 2015 ) compared with the wild type group.…”