El papel del microambiente tumoral y los fibroblastos asociados a cáncer en el desarrollo y la progresión del cáncer de mama / The role of tumor microenvironment and cancer-associated fibroblasts in breast cancer development and progression

Es bien sabido que el cáncer mamario es considerado un problema de salud a nivel mundial, la enorme tasa de mortalidad se debe a la recaída de la enfermedad, principalmente por la generación de resistencia a los diversos tratamientos. Hasta hace unos años, esta resistencia era atribuida a las mutaciones genéticas heredadas, sin embargo, evidencias recientes sugieren que el microambiente tumoral desempeña un papel clave en el desarrollo y la progresión del cáncer. La relación simbiótica entre las células tumorales y los fibroblastos asociados a cáncer (FAC), condicionan un ambiente propicio para el soporte estructural necesario, lleno de nutrientes que favorecen su crecimiento y progresión. Aquí se describe el papel que juega el microambiente tumoral y los FAC, desde su origen celular y activación, hasta los mecanismos de quimiorresistencia tumoral, además de los cambios epigenéticos y las proteínas involucradas, como las HDAC, que prometen ser blancos terapéuticos de nuevos fármacos dirigidos a su inhibición, al mitigar diversas vías que participan en la activación de los FAC o revertir su potencial promotor de tumores, lo que a su vez, mejoraría la calidad de vida de las pacientes. (AU)

It is well known that breast cancer is considered a worldwide health problem, the enormous mortality rate is due to the relapse of patients mostly due to the generation of resistance to various treatments. Until a few years ago, this resistance was attributed to inherited genetic mutations, however, recent evidence suggests that tumor microenvironment plays a key role in the development and progression of cancer. The symbiotic relationship between tumor cells and cancer-associated fibroblasts (CAF) provides an environment conducive to the necessary structural support, full of nutrients that favor their growth and progression. Here we describe the role played by the tumor microenvironment and CAF, from their cellular origin and activation to the mechanisms of tumor chemoresistance, in addition to the epigenetic changes and proteins involved, such as HDAC, which promise to be therapeutic targets for new drugs aimed at their inhibition, by mitigating various pathways involved in the activation of CAF or reversing their tumor-promoting potential, which in turn, would improve the quality of life of patients. (AU)

Arginine vasopressin deficiency and conivaptan (a V1a-V2 receptor antagonist) treatment reverses liver damage and fibrosis in rats with chronic portocaval anastomosis.

Arginine vasopressin (AVP) is a naturally occurring hormone synthesized in the hypothalamus. AVP demonstrates pro-fibrotic effects as it stimulates hepatic stellate cells to secrete transforming growth factor-ß (TGF-ß) and collagen. Previous work in liver cirrhotic (CCL4 -induced) hamsters demonstrated that AVP deficiency induced by neurointermediate pituitary lobectomy (NIL) can restore liver function. Therefore, we hypothesized that liver fibrosis would decrease in portocaval anastomosis (PCA) rats, which model chronic liver diseases, when they are treated with the V1a-V2 AVP receptor antagonist conivaptan (CV). In this study, changes in liver histology and gene expression were analysed in five experimental groups: control, PCA, NIL, PCA + NIL and PCA + CV, with NIL surgery or CV treatment administered 8 weeks after PCA surgery. Body weight gain was assessed on a weekly basis, and serum liver function, liver weight and liver glycogen content were assessed following euthanasia. Most PCA-induced phenotypes were reverted to normal levels following AVP-modelled deficiency, though hypoglycemia and ammonium levels remained elevated in the PCA + CV group. Liver histopathological findings showed a significant reversal in collagen content, less fibrosis in the triad and liver septa and increased regenerative nodules. Molecular analyses showed that the expression of fibrogenic genes (TGF-ß and collagen type I) decreased in the PCA + CV group. Our findings strongly suggest that chronic NIL or CV treatment can induce a favourable microenvironment to decrease liver fibrosis and support CV as an alternative treatment for liver fibrosis.

Recovery from Liver Failure and Fibrosis in a Rat Portacaval Anastomosis Model after Neurointermediate Pituitary Lobectomy.

Liver diseases, including cirrhosis, viral hepatitis, and hepatocellular carcinoma, account for approximately two million annual deaths worldwide. They place a huge burden on the global healthcare systems, compelling researchers to find effective treatment for liver fibrosis-cirrhosis. Portacaval anastomosis (PCA) is a model of liver damage and fibrosis. Arginine vasopressin (AVP) has been implicated as a proinflammatory-profibrotic hormone. In rats, neurointermediate pituitary lobectomy (NIL) induces a permanent drop (80%) in AVP serum levels. We hypothesized that AVP deficiency (NIL-induced) may decrease liver damage and fibrosis in a rat PCA model. Male Wistar rats were divided into intact control (IC), NIL, PCA, and PCA+NIL groups. Liver function tests, liver gene relative expressions (IL-1, IL-10, TGF-ß, COLL-I, MMP-9, and MMP-13), and histopathological assessments were performed. In comparison with those in the IC and PCA groups, bilirubin, protein serum, and liver glycogen levels were restored in the PCA+NIL group. NIL in the PCA animals also decreased the gene expression levels of IL-1 and COLL-I, while increasing those of IL-10, TGF-ß, and MMP-13. Histopathology of this group also showed significantly decreased signs of liver damage with lower extent of collagen deposition and fibrosis. Low AVP serum levels were not enough to fully activate the AVP receptors resulting in the decreased activation of cell signaling pathways associated with proinflammatory-profibrotic responses, while activating cell molecular signaling pathways associated with an anti-inflammatory-fibrotic state. Thus, partial reversion of liver damage and fibrosis was observed. The study supports the crucial role of AVP in the inflammatory-fibrotic processes and maintenance of immune competence. The success of the AVP deficiency strategy suggests that blocking AVP receptors may be therapeutically useful to treat inflammatory-fibrotic liver diseases.