Tumour: Fibroblast Interactions Promote Invadopodia-Mediated Migration and Invasion in Oral Squamous Cell Carcinoma

The β-arrestin1/endothelin axis bolsters ovarian fibroblast-dependent invadosome activity and cancer cell metastatic potential

Recruitment of fibroblasts to tumors and their activation into cancer-associated fibroblasts (CAFs) is a strategy used by tumor cells to direct extracellular matrix (ECM) remodeling, invasion, and metastasis, highlighting the need to investigate the molecular mechanisms driving CAF function. Endothelin-1 (ET-1) regulates the communication between cancer and stroma and facilitates the progression of serous ovarian cancer (SOC). By binding to Endothelin A (ETA) and B (ETB) receptors, ET-1 enables the recruitment of β-arrestin1 (β-arr1) and the formation of signaling complexes that coordinate tumor progression. However, how ET-1 receptors might "educate" human ovarian fibroblasts (HOFs) to produce altered ECM and promote metastasis remains to be elucidated. This study identifies ET-1 as a pivotal factor in the activation of CAFs capable of proteolytic ECM remodeling and the generation of heterotypic spheroids containing cancer cells with a propensity to metastasize. An autocrine/paracrine ET-1/ETA/BR/β-arr1 loop enhances HOF proliferation, upregulates CAF marker expression, secretes pro-inflammatory cytokines, and increases collagen contractility, and cell motility. Furthermore, ET-1 facilitates ECM remodeling by promoting the lytic activity of invadosome and activation of integrin β1. In addition, ET-1 signaling supports the formation of heterotypic HOF/SOC spheroids with enhanced ability to migrate through the mesothelial monolayer, and invade, representing metastatic units. The blockade of ETA/BR or β-arr1 silencing prevents CAF activation, invadosome function, mesothelial clearance, and the invasive ability of heterotypic spheroids. In vivo, therapeutic inhibition of ETA/BR using bosentan (BOS) significantly reduces the metastatic potential of combined HOFs/SOC cells, associated with enhanced apoptotic effects on tumor cells and stromal components. These findings support a model in which ET-1/β-arr1 reinforces tumor/stroma interaction through CAF activation and fosters the survival and metastatic properties of SOC cells, which could be counteracted by ETA/BR antagonists.

Mapping Cell-in-Cell Structures in Oral Squamous Cell Carcinoma

Cell-in-cell (CIC) structures contribute to tumor aggressiveness and poor prognosis in oral squamous cell carcinoma (OSCC). In vitro 3D models may contribute to the understanding of the underlying molecular mechanisms of these events. We employed a spheroid model to study the CIC structures in OSCC. Spheroids were obtained from OSCC (HSC3) and cancer-associated fibroblast (CAF) lines using the Nanoshuttle-PLTM bioprinting system (Greiner Bio-One). Spheroid form, size, and reproducibility were evaluated over time (EvosTM XL; ImageJ version 1.8). Slides were assembled, stained (hematoxylin and eosin), and scanned (Axio Imager Z2/VSLIDE) using the OlyVIA System (Olympus Life Science) and ImageJ software (NIH) for cellular morphology and tumor zone formation (hypoxia and/or proliferative zones) analysis. CIC occurrence, complexity, and morphology were assessed considering the spheroid regions. Well-formed spheroids were observed within 6 h of incubation, showing the morphological aspects of the tumor microenvironment, such as hypoxic (core) and proliferative zone (periphery) formation. CIC structures were found in both homotypic and heterotypic groups, predominantly in the proliferative zone of the mixed HSC3/CAF spheroids. "Complex cannibalism" events were also noted. These results showcase the potential of this model in further studies on CIC morphology, formation, and relationship with tumor prognosis.

HPV disrupt the cytoskeleton in oral squamous cell carcinomas from non-oropharyngeal sites via the E-cadherin/Mena/SMA pathway

In this paper, we aimed to evaluate the mechanism of actin cytoskeleton disruption, in oral squamous cell carcinoma (OSCC). A total of 43 patients with surgically resected OSCCs located in non-oropharyngeal regions were randomly selected. The expression of E-cadherin, β-catenin, smooth muscle actin (SMA), Mena, maspin, V-set and immunoglobulin domain containing 1 (VSIG1), β human chorionic gonadotropin (βhCG), and angiotensin-converting enzyme (ACE) was assessed via immunohistochemistry (IHC) and evaluated in association with the prevalence of high-risk human papillomavirus (HPV). Mena positivity (n = 30; 69.77%) was more frequent in poorly differentiated OSCC of the tongue and lips with high-risk HPV viral DNA and a lymph node ratio (LNR) ≤ 2.5. Loss of E-cadherin was more prevalent among poorly differentiated stage pT4N1 tumors with an LNR ≤ 2.5 and perineural invasion. These cases were classified as SMA-high tumors. Independent negative prognostic factors included high Mena expression, loss of E-cadherin, high SMA expression, and the presence of high-risk HPV. No VSIG1 positivity was observed. In conclusion, in non-oropharyngeal OSCC, cytoskeleton activity might be driven by the Mena/E-cadherin/SMA axis, reflecting active epithelial-mesenchymal interaction. High Mena intensity is an indicator of poorly differentiated carcinomas with high-risk HPV and unfavorable prognosis.