Magic™ Anti-PKC alpha + beta 2 polyclonal antibody

Protein kinase C alpha (PKC alpha) can activate both pro- and anti-tumorigenic signaling depending upon cellular context. Here, we investigated the role of PKC alpha in lung tumorigenesis in vivo. Gene expression data sets revealed that primary human non-small lung cancers (NSCLC) express significantly decreased PKC alpha levels, indicating that loss of PKC alpha expression is a recurrent event in NSCLC. We evaluated the functional relevance of PKC alpha loss during lung tumorigenesis in three murine lung adenocarcinoma models (LSL-Kras, LA2-Kras and urethane exposure). Genetic deletion of PKC alpha resulted in a significant increase in lung tumor number, size, burden and grade, bypass of oncogene-induced senescence, progression from adenoma to carcinoma and a significant decrease in survival in vivo. The tumor promoting effect of PKC alpha loss was reflected in enhanced Kras-mediated expansion of bronchio-alveolar stem cells (BASCs), putative tumor-initiating cells, both in vitro and in vivo. LSL-Kras/Prkca(-/-) mice exhibited a decrease in phospho-p38 MAPK in BASCs in vitro and in tumors in vivo, and treatment of LSL-Kras BASCs with a p38 inhibitor resulted in increased colony size indistinguishable from that observed in LSL-Kras/Prkca(-/-) BASCs. In addition, LSL-Kras/Prkca(-/-) BASCs exhibited a modest but reproducible increase in TGF beta 1 mRNA, and addition of exogenous TGF beta 1 to LSL-Kras BASCs results in enhanced growth similar to untreated BASCs from LSL-Kras/Prkca(-/-) mice. Conversely, a TGF beta R1 inhibitor reversed the effects of PKC alpha loss in LSL-Kras/Prkca(-/-) BASCs. Finally, we identified the inhibitors of DNA binding (Id) Id1-3 and the Wilm's Tumor 1 as potential downstream targets of PKC alpha-dependent tumor suppressor activity in vitro and in vivo. We conclude that PKC alpha suppresses tumor initiation and progression, at least in part, through a PKC alpha-p38MAPK-TGF beta signaling axis that regulates tumor cell proliferation and Kras-induced senescence. Our results provide the first direct evidence that PKC alpha exhibits tumor suppressor activity in the lung in vivo.

Embryo-induced signaling pathways are considered to be important for initiation and sustenance of pregnancy. However many of these pathways remain to be deciphered in primates. In the present study, differential display RT-PCR was used to identify genes or gene fragments that are differentially expressed in endometrium of bonnet monkeys (Macaca radiata) on Day 6 of pregnancy. Of several fragments found to be differentially expressed, a fragment of 567 base pair (named GG1) was characterized in detail. GG1 was highly represented in endometrium of pregnant animals compared with that of nonpregnant animals. Sequencing analysis revealed homology of this fragment to exons 7, 8, 9, and 10 and surprisingly to intron 6 of cAMP-dependent protein kinase A (PKA) regulatory type I alpha (tissue-specific extinguisher 1) (PRKAR1A). The increased expression of this fragment in gestational endometrium was confirmed by quantitative PCR studies. Two transcripts of 3.0 kilobase (kb) and 1.5 kb were detected in Northern blot probed with labeled GG1. Protein expressions of alpha regulatory (PRKAR1A) and alpha catalytic (PRKCA) subunits of PKA were also higher in gestational endometrium compared with that in nongestational endometrium. Further in vitro studies using human endometrial explants demonstrated regulation of PRKAR1A (or GG1) and prostaglandin-endoperoxide synthase 2 or cyclooxygenase 2 (PTGS2) by estradiol. This is the first study to date on the differential expression of PKA in primate endometrium during early pregnancy and its in vitro regulation by estradiol.