Pharmacological activation of TRPV4 produces immediate cell damage and induction of apoptosis in human melanoma cells and HaCaT keratinocytes

Abstract

BackgroundTRPV4 channels are calcium-permeable cation channels that are activated by several physicochemical stimuli. Accordingly, TRPV4 channels have been implicated in the regulation of osmosensing, mechanotransduction, thermosensation, and epithelial/endothelial barrier functions. Whether TRPV4 is also mechanistically implicated in melanoma cell proliferation is not clear. Here, we hypothesized that TRPV4 is expressed in human melanoma and that pharmacological activation interferes with cell proliferation.Methodology/Principal findingsTRPV4 functions were studied in melanoma cell lines (A375, SK-MEL-28, MKTBR), immortalized non-cancer keratinocytes (HaCaT), and murine 3T3 fibroblasts by patch-clamp, qRT-PCR, intracellular calcium measurements, cell proliferation, and flow cytometric assays of apoptosis and cell cycle. The selective TRPV4-activator, GSK1016790A, elicited non-selective cation currents with TRPV4-typical current-voltage-relationship in all cell lines. GSK1016790A-induced currents were blocked by the TRPV4-blocker, HC067047. TRPV4 mRNA expression was demonstrated by qRT-PCR. In A375 cells, TRPV4 activation was frequently paralleled by co-activation of calcium/calmodulin-regulated KCa3.1 channels. Light microscopy showed that TRPV4-activation produced rapid cellular disarrangement, nuclear densification, and detachment of a large fraction of all melanoma cell lines and HaCaT cells. TRPV4-activation induced apoptosis and drastically inhibited A375 and HaCaT proliferation that could be partially prevented by HC067047.Conclusions/SignificanceOur study showed that TRPV4 channels were functionally expressed in human melanoma cell lines and in human keratinocytes. Pharmacological TRPV4 activation in human melanoma cells and keratinocytes caused severe cellular disarrangement, necrosis and apoptosis. Pharmacological targeting of TRPV4 could be an alternative or adjuvant therapeutic strategy to treat melanoma progression and other proliferative skin disorders.

Activation of PTEN by inhibition of TRPV4 suppresses colon cancer development

“…In hepatocellular carcinoma cells, TRPC6 is a negative regulator of cell death induced by doxorubicin, hypoxia, and ionizing radiation 36 . In contrast to TRPC6, TRPV4 is positively regulated pronounced cell death through apoptosis, oncosis, or necrosis in breast cancer or melanoma cells 11,37 . In addition, sustained exposure to TRPV4 agonists has been shown to evoke dose-dependent apoptosis of retinal ganglion cells and hippocampal neuronal cells 38 .…”

Weak Ultraviolet B Enhances the Mislocalization of Claudin-1 Mediated by Nitric Oxide and Peroxynitrite Production in Human Keratinocyte-Derived HaCaT Cells

“…Transient receptor potential vanilloid (TRPV) is a molecular sensor for detecting adverse stimuli such as capsaicin, heat, and acid. TRPV1 and 4 are expressed in keratinocytes and function as a Ca 2+ channel [ 23 , 24 ]. To clarify the Ca 2+ influx pathway caused by UVB irradiation, we investigated the effects of TRPV1 and TRPV4 antagonists.…”

Conditional KCa3.1-transgene induction in murine skin produces pruritic eczematous dermatitis with severe epidermal hyperplasia and hyperkeratosis

“…The physiological and pathophysiological significance of KCa3.1 in the skin has been elusive until now. So far, keratinocyte KCa3.1 has been studied-superficially though-by mRNAexpression experiments in cultured human keratinocytes [5] and immune histochemistry in rat epidermis [39], which did not provide much information about the role of the channel in epidermal homeostasis in-vivo. Here, we intended to provide new knowledge by generating a murine model of genetic conditional induction of a murine KCa3.1-transgene in epidermis (Fig 1).…”

“…Ion channels have long been known to contribute to the pathophysiology of inflammatory, autoimmune [1], and proliferative diseases [2][3][4]. More recently, several calcium-permeable channels of the transient receptor potential family (TRP) and potassium channels have been found to be involved in skin conditions, such as melanoma [5], psoriasis [6], atopic dermatitis [7], Olmsted syndrome [8], and rosacea [9][10][11], suggesting the respective channels as potential treatment targets.…”

“…However, concerning the skin, the physiological role of KCa3.1 and its pathophysiological significance for human skin disease is largely unexplored. So far, KCa3.1 protein expression and/or mRNA message have been found in rat epidermis [39], in human keratinocytes and melonama [5], where pharmacological inhibition of KCa3.1 has anti-proliferative efficacy in vitro. Yet, the role of KCa3.1 in the healthy or diseased epidermis remains elusive.…”