Melanoma is a lethal form of skin cancer triggered by genetic and environmental factors. Excision of early-stage, poorly aggressive melanoma often leads to a successful outcome; however, left ...undiagnosed these lesions can progress to metastatic disease. This research investigates whether the exposure of poorly aggressive melanoma to certain normal skin cells can explain how non-metastatic melanoma becomes more aggressive while still confined to the skin. To this end, we used a serial co-culture approach to sequentially expose cells from two different, poorly aggressive human melanoma cell lines against normal cells of the skin beginning with normal melanocytes, then epidermal keratinocytes, and finally dermal fibroblasts. Protein extraction of melanoma cells occurred at each step of the co-culture sequence for western blot (WB) analysis. In addition, morphological and functional changes were assessed to detect differences between the serially co-cultured melanoma cells and non-co-cultured cells. Results show that the co-cultured melanoma cells assumed a more mesenchymal morphology and displayed a significant increase in proliferation and invasiveness compared to control or reference cells. WB analysis of protein from the co-cultured melanoma cells showed increased expression of Snail and decreased levels of E-cadherin suggesting that epithelial-to-mesenchymal transition (EMT) is occurring in these co-cultured cells. Additional WB analysis showed increased levels of Nodal protein and signaling and signs of increased Wnt activity in the co-cultured melanoma cells compared to reference cells. These data suggest that interaction between poorly aggressive melanoma cells with normal cells of the skin may regulate the transition from localized, poorly aggressive melanoma to invasive, metastatic disease via Nodal and/or Wnt induced EMT.
Role of Presenilin-1 in Aggressive Human Melanoma Sidor, Julia; Gillette, Megan; Dezi, Lindsay Ann ...
International journal of molecular sciences,
04/2022, Letnik:
23, Številka:
9
Journal Article
Recenzirano
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Presenilin-1 (PS-1), a component of the gamma (γ)-secretase catalytic complex, has been implicated in Alzheimer's disease (AD) and in tumorigenesis. Interestingly, AD risk is inversely related to ...melanoma, suggesting that AD-related factors, such as PS-1, may affect melanomagenesis. PS-1 has been shown to reduce Wnt activity by promoting degradation of beta-catenin (β-catenin), an important Wnt signaling partner. Since Wnt is known to enhance progression of different cancers, including melanoma, we hypothesized that PS-1 could affect Wnt-associated melanoma aggressiveness. Western blot results showed that aggressive melanoma cells expressed significantly lower levels of both PS-1 and phosphorylated-β-catenin (P-β-catenin) than nonaggressive melanoma cells. Immunohistochemistry of human melanoma samples showed significantly reduced staining for PS-1 in advanced stage melanoma compared with early stage melanoma. Furthermore, γ-secretase inhibitor (GSI) treatment of aggressive melanoma cells was followed by significant increases in PS-1 and P-β-catenin levels, suggesting impaired Wnt signaling activity as PS-1 expression increased. Finally, a significant reduction in cell migration was associated with the higher levels of PS-1 and P-β-catenin in the GSI-treated aggressive melanoma cells. We demonstrate for the first time that PS-1 levels can be used to assess melanoma aggressiveness and suggest that by enhancing PS-1 expression, Wnt-dependent melanoma progression may be reduced.
Wnt signalling induces a gradient of stem/progenitor cell proliferation along the crypt‐villus axis of the intestine, which becomes expanded during intestinal regeneration or tumour formation. The ...YAP transcriptional co‐activator is known to be required for intestinal regeneration, but its mode of regulation remains controversial. Here we show that the YAP‐TEAD transcription factor is a key downstream effector of Wnt signalling in the intestine. Loss of YAP activity by Yap/Taz conditional knockout results in sensitivity of crypt stem cells to apoptosis and reduced cell proliferation during regeneration. Gain of YAP activity by Lats1/2 conditional knockout is sufficient to drive a crypt hyperproliferation response. In particular, Wnt signalling acts transcriptionally to induce YAP and TEAD1/2/4 expression. YAP normally localises to the nucleus only in crypt base stem cells, but becomes nuclear in most intestinal epithelial cells during intestinal regeneration after irradiation, or during organoid growth, in a Src family kinase‐dependent manner. YAP‐driven crypt expansion during regeneration involves an elongation and flattening of the Wnt signalling gradient. Thus, Wnt and Src‐YAP signals cooperate to drive intestinal regeneration.
Synopsis
How the YAP‐TEAD transcriptional factor is regulated during intestinal repair and colorectal cancer remains debated. Here, genetic work identifies YAP and TEAD as transcriptional targets of Wnt signalling, with YAP nuclear localisation governed by Src family kinases, highlighting unexpected signal cooperation during murine tissue regeneration.
Depletion of Yap/Taz increases crypt stem cell apoptosis and reduces proliferation during regeneration in vivo.
Conditional activation of Yap/Taz by Lats1/2 depletion induces YAP nuclear localisation and crypt hyperplasia.
Genetic activation of Wnt signalling induces transcript expression of YAP and TEAD1/2/4 in intestinal organoids or tumours.
Irradiation‐induced nuclear localisation of YAP‐TEAD is regulated by Src family kinase, YAP‐TEAD activity and crypt regeneration are Wnt‐dependent.
Wnt transcriptionally controls YAP and TEAD expression to enable Src‐dependent activation of YAP‐TEAD activity during intestinal regeneration.
B2B companies winning the most market share are simultaneously employing five major modern sales and marketing tactics: deploying advanced sales technology, increasing hybrid sales teams and ...capabilities, delivering hyperpersonalization, tailoring strategies on third-party marketplaces, and achieving e-commerce excellence across the full marketing and sales funnel. Companies winning market share have not only digital self-serve channels such as their own websites but also broader e-commerce offerings. The adoption of larger hybrid teams is correlated with greater market share gains, especially in TMT; finance, banking, and insurance; and travel, transportation, and logistics. The benefits from hybrid sales models are not exclusive to large companies: respondents from small to midsize companies with larger hybrid adoption rates reported seeing greater share gains.
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