CDKN2D

Abstract: Cyclin-dependent kinase (CDK) inhibitors represented by the INK4 family (including p16INK4a, CDKN2A, p15INK4b, CDKN2B, p18INK4c, CDKN2C, and p19INK4d, CDKN2D) are regulators of the cell cycle shown to be aberrant in many types of human cancer. We tested the hypothesis that these CDK inhibitors are a target for altered gene expression in Wilms tumor. Using RT-PCR, gene expression of the INK4 family was found to be decreased in 9 of 38 Wilms tumor samples obtained from the National Wilms Tumor Study Group (NWTSG) tissue bank. All the affected tumor samples were of favorable histology. Methylation-specific PCR revealed that methylation in the p16 promoter region may be responsible for altered expression. The incidence of loss of p16 expression may increase with increasing tumor stage, i.e., 1/10 (10%) with stage I/II FH Wilms tumor, 2/10 (20%) with stage III FH Wilms tumor, and 4/10 (40%) with stage IV FH Wilms tumor. Thus, determining the expression status of the INK4 family may have potential prognostic value in the management of Wilms tumor. Genes Chromosomes Cancer 29:63–69, 2000. © 2000 Wiley-Liss, Inc.

Abstract: SSeCKS is a major protein kinase C substrate with kinase scaffolding and metastasis-suppressor activity whose expression is severely downregulated in Src- and Ras-transformed fibroblast and epithelial cells and in human prostate, breast, and gastric cancers. We previously used NIH3T3 cells with tetracycline-regulated SSeCKS expression plus a temperature-sensitive v-Src allele to show that SSeCKS re-expression inhibited parameters of v-Src-induced oncogenic growth without attenuating in vivo Src kinase activity. We use cDNA microarrays and semi-quantitative RT-PCR analysis to identify changes in gene expression correlating with i) SSeCKS expression in the absence of v-Src activity, ii) activation of v-Src activity alone, and iii) SSeCKS re-expression in the presence of active v-Src. SSeCKS re-expression resulted in the attenuation of critical Src-induced proliferative and pro-angiogenic gene expression including Afp, Hif-1α, Cdc20a and Pdgfr-β, and conversely, SSeCKS induced several cell cycle regulatory genes such as Ptpn11, Gadd45a, Ptplad1, Cdkn2d (p19), and Rbbp7. Our data provide further evidence that SSeCKS can suppress Src-induced oncogenesis by modulating gene expression downstream of Src kinase activity.

Abstract: When a murine macrophage cell line, RAW264, was stimulated with lipopolysaccharide (LPS), cell cycle arrest was observed. DNA microarray analysis clarified that out of the 99 cell cycle-related genes, LPS significantly up-regulated 4 genes; two major of which were cyclin-dependent kinase inhibitor 2D (cdkn2d) and nuclear factor of kappa light chain gene enhancer (Nfkbia), and down-regulated 1 gene, namely cyclin A2 (Ccna2). These gene expressions could directly account for the cell cycle arrest of the macrophage examined.

Abstract: Infertility affects 10-15% of couples worldwide, and male factors account for 50%. Spermatogenesis is precisely regulated by genetic factors, and the mutations of genes result in abnormal spermatogenesis and eventual male infertility. The aim of this study was to explore the role and transcriptional regulation of P63 in the apoptosis and mouse spermatogenesis. P63 protein was decreased in male germ cells of P63(+/-) mice compared with wild-type mice. There was no obvious difference in testis weight, sperm motility, and fecundity between P63(+/-) and wild-type mice. However, abnormal germ cells were frequently observed in P63(+/-) mice at 2 months old. Notably, apoptotic male germ cells and the percentage of abnormal sperm were significantly enhanced in P63(+/-) mice compared to wild-type mice. Spermatogonia, pachytene spermatocytes and round spermatids were isolated from P63(+/-) and wild-type mice using STA-PUT velocity sedimentation, and they were identified phenotypically with high purities. RNA sequencing demonstrated distinct transcription profiles in spermatogonia, pachytene spermatocytes, and round spermatids between P63(+/-) mice and wild-type mice. In total, there were 645 differentially expressed genes (DEGs) in spermatogonia, 106 DEGs in pachytene spermatocytes, and 1152 in round spermatids between P63(+/-) mice and wild-type mice. Real time PCR verified a number of DEGs identified by RNA sequencing. Gene ontology annotation and pathway analyzes further indicated that certain key genes, e.g., Ccnd2, Tgfa, Hes5, Insl3, Kit, Lef1, and Jun were involved in apoptosis, while Dazl, Kit, Pld6, Cdkn2d, Stra8, and Ubr2 were associated with regulating spermatogenesis. Collectively, these results implicate that P63 mediates the apoptosis of male germ cells and regulates three stages of spermatogenesis transcriptionally. This study could provide novel targets for the diagnosis and treatment of male infertility.