title: Suppression of prolactin signaling by pyrrolidine dithiocarbamate is alleviated by N-acetylcysteine in mammary epithelial cells.
abstract: Prolactin is the key hormone to stimulate milk synthesis in mammary epithelial cells. It signals through the Jak2-Stat5 pathway to induce the expression of β-casein, a milk protein which is often used as a marker for mammary differentiation. Here we examined the effect of pyrrolidine dithiocarbamate (PDTC) on prolactin signaling. Our results show that PDTC downregulates prolactin receptor levels, and inhibits prolactin-induced Stat5 tyrosine phosphorylation and β-casein expression. This is not due to its inhibitory action on NF-κB since application of another NF-κB inhibitor, BAY 11-7082, and overexpression of I-κBα super-repressor do not lead to the same results. Instead, the pro-oxidant activity of PDTC is involved as inclusion of the antioxidant N-acetylcysteine restores prolactin signaling. PDTC triggers great extents of activation of ERK and JNK in mammary epithelial cells. These do not cause suppression of prolactin signaling but confer serine phosphorylation of insulin receptor substrate-1, thereby perturbing insulin signal propagation. As insulin facilitates optimal β-casein expression, blocking insulin signaling by PDTC might pose additional impediment to β-casein expression. Our results thus imply that lactation will be compromised when the cellular redox balance is dysregulated, such as during mastitis.
authors: Department of Obstetrics and Gynecology, Antai Tian-Sheng Memorial Hospital, Pingtung 928, Taiwan, Republic of China.
authors: Jen-Hsing
authors: JH
authors: Wang
authors: Institute of Microbiology and Immunology, Chung Shan Medical University, Taichung 402, Taiwan, Republic of China.
authors: Jyun-Yi
authors: JY
authors: Du
authors: Department of Medical Laboratory Science and Technology, China Medical University and Hospital, Taichung 404, Taiwan, Republic of China.
authors: Yi-Ying
authors: YY
authors: Wu
authors: Institute of Microbiology and Immunology, Chung Shan Medical University, Taichung 402, Taiwan, Republic of China.
authors: Meng-Chi
authors: MC
authors: Chen
authors: Institute of Microbiology and Immunology, Chung Shan Medical University, Taichung 402, Taiwan, Republic of China.
authors: Chun-Hao
authors: CH
authors: Huang
authors: Institute of Microbiology and Immunology, Chung Shan Medical University, Taichung 402, Taiwan, Republic of China.
authors: Hsin-Ju
authors: HJ
authors: Shen
authors: Institute of Microbiology and Immunology, Chung Shan Medical University, Taichung 402, Taiwan, Republic of China.
authors: Chin-Feng
authors: CF
authors: Lee
authors: Department of Biomedical Sciences, Chung Shan Medical University, Taichung 402, Taiwan, Republic of China.
authors: Ting-Hui
authors: TH
authors: Lin
authors: Institute of Microbiology and Immunology, Chung Shan Medical University, Taichung 402, Taiwan, Republic of China; Department of Medical Research, Chung Shan Medical University Hospital, Taichung 402, Taiwan, Republic of China. Electronic address: yijulee@csmu.edu.tw.
authors: Yi-Ju
authors: YJ
authors: Lee
mesh_terms: D000111:Acetylcysteine / Q000494:pharmacology*; D000818:Animals; D002364:Caseins / Q000235:genetics; D002417:Cattle; D004847:Epithelial Cells / Q000166:cytology* / Q000187:drug effects* / Q000378:metabolism; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects; D007328:Insulin / Q000378:metabolism; D055504:Insulin Receptor Substrate Proteins / Q000737:chemistry / Q000378:metabolism; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D008321:Mammary Glands, Animal / Q000166:cytology; D051379:Mice; D016328:NF-kappa B / Q000037:antagonists & inhibitors; D010766:Phosphorylation / Q000187:drug effects; D011247:Pregnancy; D011388:Prolactin / Q000378:metabolism*; D011759:Pyrrolidines / Q000037:antagonists & inhibitors* / Q000494:pharmacology*; D012694:Serine / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects*; D013859:Thiocarbamates / Q000037:antagonists & inhibitors* / Q000494:pharmacology*
chemical_list: D002364:Caseins; D007328:Insulin; D055504:Insulin Receptor Substrate Proteins; C526295:Irs1 protein, mouse; D016328:NF-kappa B; D011759:Pyrrolidines; D013859:Thiocarbamates; C020972:pyrrolidine dithiocarbamic acid; D012694:Serine; D011388:Prolactin; D048049:Extracellular Signal-Regulated MAP Kinases; D048031:JNK Mitogen-Activated Protein Kinases; D000111:Acetylcysteine
keywords: Insulin; Mammary epithelial cells; PDTC; Prolactin; Signal transduction