PP2B and ERK1/2 regulate hyaluronan synthesis of HT168 and WM35 human melanoma cell lines

Abstract

Hyaluronan (HA) is the major glycosaminoglycan component of the extracellular matrix in either normal or malignant tissues and it may affect proliferation, motility and differentiation of various cell types. Three isoforms of plasma membrane-bound hyaluronan synthases (HAS 1, 2 and 3) secrete and simultaneously bind pericellular HA. HAS enzymes are subjects of post-translational protein phosphorylation which is believed to regulate their enzymatic activity. In this study, we investigated the HA homeostasis of normal human epidermal melanocytes, HT168 and WM35 human melanoma cell lines and melanoma metastases. HAS2 and HAS3 were detected in all the samples, while the expression of HAS1 was not detectable in any case. Malignant tissue samples and melanoma cell lines contained extra- and intracellular HA abundantly but not normal melanocytes. Applying HA as a chemoattractant facilitated the migration of melanoma cells in Boyden chamber. The amount of HA was reduced upon the inhibition of calcineurin with cyclosporine A (CsA), while the inhibition of ERK1/2 with PD098059 elevated it in both cell lines. The signals of Ser/Thr phosphoproteins at 57 kD were stronger after CsA treatment, while a markedly weaker signal was detected upon inhibition of the MAPK pathway. Our results suggest opposing effects of the two investigated enzymes on the HA homeostasis of melanoma cells. We propose that the dephosphorylation of HAS enzymes targeted by PP2B augments HA production, while their phosphorylation by the activity of MAPK pathway reduces HA synthesis. As the expression of the HA receptor RHAMM was also significantly enhanced by PD098059, the MAPK pathway exerted a complex attenuating effect on HA signalling in the investigated melanoma cells. This observation suggests that the application of MAPK-ERK pathway inhibitors requires a careful therapeutic design in melanoma treatment.

Pituitary Adenylate Cyclase Activating Polypeptide (PACAP) Reduces Oxidative and Mechanical Stress-Evoked Matrix Degradation in Chondrifying Cell Cultures

“…These findings suggest that PACAP has an important function in hyaluronic acid turnover via the activation of hyaluronic acid synthases and regulation of hyaluronan degradation. However, the addition of hyaluronic acid is able to prevent the harmful effects of oxidative stress [42] and induces migration of tumor cells [43], but no clear data can be found in connection with hyaluronan catabolism.…”

Melanocyte Hyaluronan Coat Fragmentation Enhances the UVB-Induced TLR-4 Receptor Signaling and Expression of Proinflammatory Mediators IL6, IL8, CXCL1, and CXCL10 via NF-κB Activation

“…This disappearance of hyaluronan in tumor tissue correlates with the loss of HAS1 and HAS2, and is associated with increased recurrence of melanoma and short disease-specific survival time (Poukka et al, 2016). Although the tumor tissue is almost hyaluronan negative in melanoma, tumor cells stimulate its synthesis in stromal fibroblasts (Pasonen-Seppänen et al, 2012b;Willenberg et al, 2012) and metastases (Katona et al, 2016).…”

“…Because very little is known about hyaluronan in melanocytes (Bhavanandan, 1981;Katona et al, 2016), we characterized hyaluronan and the enzymes related to its metabolism, and we explored the contribution of hyaluronan to UVB-induced inflammation in primary melanocytes. The results suggest that hyaluronan and its fragmentation are involved in the inflammatory effects of UVB and melanocyte susceptibility to early melanoma development.…”

Age-related alterations of articular cartilage in pituitary adenylate cyclase–activating polypeptide (PACAP) gene–deficient mice

“…Increased MMP activity was detected in the ECM of cardiac muscle tissue during aging (Meschiari et al 2017), but we showed a PACAP-dependent reduction of MMPs in mechanical overload of chondrogenic cell cultures (Szentleleky et al 2019). RHAMM is an intracellular HA-binding receptor which can be activated by ERK (Katona et al 2016). Its expression is reduced in aged PACAP KO animals, suggesting that intracellular HA function is decreased as it was demonstrated in skin aging (Tzellos et al 2009).…”