FGFR2c Upregulation Contributes to Cancer-Associated Fibroblast Program Activation and to Enhanced Autophagy in Actinic Keratosis-Derived Dermal Fibroblasts: A Possible Role in Precancerous Cell/Stromal Cell Crosstalk

TRPA1 Contributes to FGFR2c Signaling and to Its Oncogenic Outcomes in Pancreatic Ductal Adenocarcinoma-Derived Cell Lines

Fibroblast growth factor receptor (FGFR) signaling is a key modulator of cellular processes dysregulated in cancer. We recently found that the high expression of the mesenchymal FGFR2c variant in human pancreatic ductal adenocarcinoma (PDAC)-derived cells triggers the PKCε-mediated improvement of EMT and of MCL-1/SRC-dependent cell invasion. Since other membrane proteins can affect the receptor tyrosine kinase signaling, including transient receptor potential channels (TRPs), in this work, we investigated the role of TRPs in the FGFR2c/PKCε oncogenic axis. Our results highlighted that either the FGFR2c/PKCε axis shut-off obtained by shRNA or its sustained activation via ligand stimulation induces TRPA1 downregulation, suggesting a channel/receptor dependence. Indeed, biochemical molecular and immunofluorescence approaches demonstrated that the transient depletion of TRPA1 by siRNA was sufficient to attenuate FGFR2c downstream signaling pathways, as well as the consequent enhancement of EMT. Moreover, the biochemical check of MCL1/SRC signaling and the in vitro assay of cellular motility suggested that TRPA1 also contributes to the FGFR2c-induced enhancement of PDAC cell invasiveness. Finally, the use of a selective channel antagonist indicated that the contribution of TRPA1 to the FGFR2c oncogenic potential is independent of its pore function. Thus, TRPA1 could represent a putative candidate for future target therapies in PDAC.

A Panel of Potential Serum Markers Related to Angiogenesis, Antioxidant Defense and Hypoxia for Differentiating Cutaneous Squamous Cell Carcinomas from Actinic Keratoses

Cutaneous squamous cell carcinoma (cSCC) arising from the malignant proliferation of epidermal keratinocytes is the second most common skin cancer. Actinic keratosis (AK), which is considered cSCC in situ, may progress into invasive tumors. Currently, there are no serum markers that can differentiate cSCC from AK. The aim of our study was to assess angiogenesis and oxidative stress in patients with cSCC and patients with AK and find reliable serum markers useful in the diagnosis of cSCC. We have determined the serum levels of a group of proangiogenic factors (MMP-2, MMP-9, VEGF, FGF2), the total antioxidative status/capacity (TAS/TAC), ImAnOx, a marker of oxidative stress, and HIF-1 alpha, an indicator of hypoxia. We have identified higher serum levels of MMP-2. MMP-9, VEGF, FGF2 and HIF-1 alpha and lower levels of ImAnOx in cSCC patients compared to AK patients and controls. There were no statistically significant differences between AK patients and controls. We have found positive correlations between proangiogenic markers and HIF-1 alpha and negative correlations between proangiogenic markers and ImAnOx. Our results suggest that MMP-2, MMP-9, VEGF, FGF2, ImAnOx and HIF-1 may be promising markers for differentiating AK from cSCC, and there is a link between angiogenesis, oxidative stress and hypoxia.