Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P43146 (tumour suppressor)
 5,935 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Malignant melanoma is the deadliest form of skin cancer. Previous studies have shown that the incidence of ras mutation increases with progression of melanoma, but that such mutations may not be present in the earliest radial growth phase melanomas. Recently it has been proposed that introduction of ras mutations into cells deficient in tumour suppressor genes such as p16 (INK4a) is sufficient to induce characteristics of cellular transformation such as anchorage-independent growth and tumour formation in vivo. To test this hypothesis in human melanoma, mutant N-ras, mutant H-ras or wild-type H-ras genes were transfected by electroporation into WM35 cells, a p16-deficient human melanoma cell line of low invasive potential. Increased expression of mutant ras p21 enhanced anchorage-dependent cell growth on tissue culture plastic. In addition, overexpression of mutant N-ras and H-ras, but not of wild-type H-ras, increased the experimental invasive potential, inducing anchorage-independent growth in soft agar, increasing cell motility measured by time-lapse video microscopy, and increasing invasiveness through reconstituted basement membranes. Finally, overexpression of mutant H-ras in melanoma cells was shown to increase tumorigenicity and to induce cachexia when H-ras transfected cell lines were injected subcutaneously in severe combined immunodeficiency (SCID) mice. Thus the addition of activating ras mutations to a melanoma cell line already deficient in p16 leads to enhanced proliferation, survival and migration in vitro and to enhanced subcutaneous tumour formation in vivo. This phenotype is typical of the behaviour of vertical growth phase (VGP) melanoma, and we propose that activation of the ras signalling pathway in the presence of deletions in p16 or related tumour suppressors can induce the VGP melanoma phenotype.
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PMID:Overexpression of mutant ras in human melanoma increases invasiveness, proliferation and anchorage-independent growth in vitro and induces tumour formation and cachexia in vivo. 1046 84

Cancer cachexia is a metabolic syndrome featuring many alterations typical of type 2 diabetes (T2D). While muscle wasting is a hallmark of cachexia, epidemiological evidence also supports an accelerated age-related muscle loss in T2D. Insulin resistance manifests in both conditions and impairs glucose disposal and protein anabolism by tissues. A greater contribution of gluconeogenesis to glucose production may limit amino acid availability for muscle protein synthesis, further aggravating muscle loss. In the context of inter-dependence between glucose and protein metabolism, the present review summarizes the current state of knowledge on alterations that may lead to muscle wasting in human cancer. By highlighting the similarities with T2D, a disease that has been more extensively studied, the objective of this review is to provide a better understanding of the pathophysiology of cancer cachexia and to consider potential treatments usually targeted for T2D. Nutritional approaches aimed at stimulating protein anabolism might include specially formulated food with optimal protein and amino acid composition. Because the gradual muscle loss in T2D may be attenuated by diabetes treatment, anti-diabetic drugs might be considered in cachexia treatment. Metformin emerges as a choice candidate as it acts both on reducing gluconeogenesis and improving insulin sensitivity, and has demonstrated tumour suppressor properties in multiple cancer types. Such a multimodal approach to slow or reverse muscle wasting in cachexia warrants further investigation.
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PMID:Cancer cachexia and diabetes: similarities in metabolic alterations and possible treatment. 2486 69

Loss of function mutations in the Prkar1a gene are the cause of most cases of Carney complex disorder. Defects in Prkar1a are thought to cause hyper-activation of PKA signalling, which drives neoplastic transformation, and Prkar1a is therefore considered to be a tumour suppressor. Here we show that loss of Prkar1a in genetically modified mice caused transcriptional activation of several proapoptotic Bcl-2 family members and thereby caused cell death. Interestingly, combined loss of Bim and Prkar1a increased colony formation of fibroblasts in culture and promoted their growth as tumours in immune-deficient mice. Apart from inducing apoptosis, systemic deletion of Prkar1a caused cachexia with muscle loss, macrophage activation and increased lipolysis as well as serum triglyceride levels. Loss of single allele of Prkar1a did not enhance tumour development in a skin cancer model, but surprisingly, when combined with the loss of Bim, caused a significant delay in tumorigenesis and this was associated with upregulation of other BH3-only proteins, PUMA and NOXA. These results show that loss of Prkar1a can only promote tumorigenesis when Prkar1a-mediated apoptosis is somehow countered.
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PMID:Loss of Prkar1a leads to Bcl-2 family protein induction and cachexia in mice. 2501 5