Prenatal nicotine exposure increases osteoarthritis susceptibility in male elderly offspring rats via low-function programming of the TGF beta signaling pathway
TOXICOLOGY LETTERS
Authors: Chen, Biao; Lu, Kai-hang; Ni, Qu-bo; Li, Qing-xian; Gao, Hui; Wang, Hui; Chen, Liao-bin
Abstract
Epidemiological investigations indicate that effects related to prenatal adverse environments on the organs of the offspring could continue to adulthood. This study intends to confirm that prenatal nicotine exposure (PNE) increases the susceptibility of osteoarthritis (OA) in the male offspring, and to explore the potential intrauterine programming mechanism. During pregnancy, rats were divided into a PNE group and a control group. After birth, rats were given a high-fat diet for 6 months and long-distance running for 6 weeks. The rats were euthanized at 18 months after birth (PM18) and on gestational day 20 (GD20), respectively. Knee joints were collected for histochemistry, immunohistochemistry, and quantitative polymerase chain reaction (qPCR) assays. Histological analyses and the Mankin's score showed increased cartilage destruction and accelerated OA progression in adult offspring from the PNE group. Immunohistochemistry results showed decreased expression of transforming growth factor beta (TGF beta) signaling pathway. Furthermore, the expression of apoptosis factors (caspase-3 and caspase-8), inflammatory factors [interleukin (IL)-1, IL-6] and matrix degradation enzymes [matrix metalloproteinase (MMP)-3, MMP-13] were also significantly increased. Traced back to the intrauterine period, it was found that the number of chondrocytes and the contents of Col2A1 and aggrecan in the matrix in the PNE group were decreased. And, the expression of the TGF beta signaling pathway was inhibited. These results suggested that PNE enhanced the susceptibility of OA in male elderly offspring rats by down-regulating TGF beta signaling, which increased articular cartilage local inflammation, matrix degradation, and cell apoptosis. This study confirmed the developmental origin of OA, and clarified the congenital and the living environment impact on the occurrence and development of OA. Our findings provide a theoretical and experimental basis for OA early prevention.
Extracellular Matrix/Integrin Signaling Promotes Resistance to Combined Inhibition of HER2 and PI3K in HER2(+) Breast Cancer
CANCER RESEARCH
Authors: Hanker, Ariella B.; Estrada, Monica Valeria; Bianchini, Giampaolo; Moore, Preston D.; Zhao, Junfei; Cheng, Feixiong; Koch, James P.; Gianni, Luca; Tyson, Darren R.; Sanchez, Violeta; Rexer, Brent N.; Sanders, Melinda E.; Zhao, Zhongming; Stricker, Thomas P.; Arteaga, Carlos L.
Abstract
PIK3CA mutations are associated with resistance to HER2-targeted therapies. We previously showed that HER2(+)/PIK3CA(H1047R) transgenic mammary tumors are resistant to the HER2 antibodies trastuzumab and pertuzumab but respond to PI3K inhibitor buparlisib (TPB). In this study, we identified mechanisms of resistance to combined inhibition of HER2 and PI3K. TPB-resistant tumors were generated by treating HER2(+)/PIK3CA(H1047R) tumor-bearing mice long term with the drug combination. RNA sequencing of TPB-resistant tumors revealed that extracellular matrix and cell adhesion genes, including collagen II (Col2a1), were markedly upregulated, accompanied by activation of integrin beta 1/Src Cells derived from drug-resistant tumors were sensitive to TBP when grown in vitro, but exhibited resistance when plated on collagen or when reintroduced into mice. Drug resistance was partially reversed by the collagen synthesis inhibitor ethyl-3,4-dihydroxybenzoate. Inhibition of integrin beta 1/Src blocked collagen- induced resistance to TPB and inhibited growth of drug-resistant tumors. High collagen II expression was associated with significantly lower clinical response to neoadjuvant anti-HER2 therapy in HER2(+) breast cancer patients. Overall, these data suggest that upregulation of collagen/integrin/Src signaling contributes to resistance to combinatorial HER2 and PI3K inhibition. (C) 2017 AACR.