1a) according to which growth-promoting proteins such as insulin that are known to be capable of translocating across cellular membranes may equally convey, if present in abnormal tissue concentrations, initial pathologic signals to proximal and distant tissues and thus contribute to their malignant transformation
prior to the occurrence of any (epi)genetic buy RG7112 and/or chromosomal alterations [17, 18]. Thereby, I had also surmised that defective tumor-suppressive mechanisms in such OPM-affected tissues would partly account for the differential organ preference of various tumor metastases [17]. Figure 1 Schematic definition of the process of oncoprotein metastasis (OPM) accompanied by physical interactions between oncoproteins (OPs) and tumor suppressor proteins (TSPs): a) spatially, consisting
www.selleckchem.com/products/dinaciclib-sch727965.html in the local, tissular penetration of OPs into cells adjacent to the cells from which the OPs originate (thereby extending the paracrine principle) and/or their systemic spread via blood and Saracatinib concentration lymphatic vessels to distant tissues/organs (thereby extending the endocrine principle), each of which would be ensued by (e.g. nucleocrine [28, 31]) OP-TSP complex formations (OP × TSP); it should be also stated here that the OP-secreting cells are not necessarily tumor cells, but could be normal cells, e.g. pancreatic β-cells that secrete (excessive amounts of) insulin in response to (blood-borne) tumoral stimuli and thus cause a well-known (cancer-associated) state of hyperinsulinemia; b) temporally, consisting in the OPM-associated and carcinogenesis-initiating event of OP-TSP complex formations (OP × TSP) that precede the epigenetic silencing of the corresponding
tumor suppressor gene-caused by the hypermethylation of its promoter-which in turn is subsequently functionally mimicked by a loss of heterozygosity (LOH) Venetoclax of the same gene, all of which changes would occur in (morphologically) normal, yet likely premalignant cells. Interestingly, this novel putative mechanism not only relates in part to a long-standing (protein deletion) theory advanced in the pre-molecular era of cancer research [22], but may also account for the increased probability of distant metastasis and extensive-stage disease correlating with poor outcome in tumor patients in which an ectopic hormone production (along with a paraneoplastic syndrome) has been ascertained [23–25]. Although this insight on a possible oncoprotein metastasis-that had been based primarily on many preceding studies on the hyperinsulinemia-cancer connection and on the presence of insulin in tumor cells-is still relatively new, there have been recent experimental reports that provide further support for this assumption.