Optimal lactation early in life activates the extrinsic apoptotic pathway in mammary tumors in adulthood.

SANTIANO, F.E.; SASSO, C.V.; ZYLA, L.E.; CAMPO VERDE ARBOCCO, F.; LÓPEZ AGUILERA, F.; BRUNA, F. A.; PISTONE-CREYDT, V.; LÓPEZ-FONTANA, C.M.; CARON, R.W.

Buenos Aires

Congreso; Reunión conjunta de sociedades de Biociencias; 2017

Sociedad Argentina de Investigación Clínica

Studies in rodent models show that exposures to diet during theposnatal life, in periods when the mammary gland undergoes extensivemodeling and re-modeling, alter susceptibility to carcinogen-induced mammary tumors. The objective of the present studywas to analyze if adequate breastfeeding generates changes in thebiology of mammary tumors developed in adult life. To do this weused Sprague Dawley female litters divided into 3 (L3), 8 (L8) or12 (L12) pups per mother, and, at the age of 55 days, they weretreated with a single dose of dimethylbenzanthracene (15 mg / rat)to study the latency, incidence, progression and tumor bilology. Weperformed a microscopic analysis of mitosis and apoptosis to assesthe effect of differential lactation on the development of the tumors.We additionally evaluated mitosis by IHC of PCNA and determinedthe expression of caspase 8, Bid, Bax, Bcl2 and caspase 9 by westernblot from the tumors. Incidence was expressed as percentagesand compared by Fisher test. Other comparisons were performedby ANOVA I and Bonferroni?s test as post hoc. There was a lowerincidence and a higher latency in L3 compared to the other groups.The mitotic index was significantly augmented in tumors of L12 ratscompared with L3 and L8 (p