Carcinoma, Hepatocellular ; metabolism ; pathology ; Cyclin-Dependent Kinase Inhibitor p27 ; metabolism ; Humans ; Liver Neoplasms ; metabolism ; pathology ; Neoplasm Staging ; Phosphorylation ; S-Phase Kinase-Associated Proteins ; metabolism

OBJECTIVETo study the effect of all-trans retinoic acid (ATRA) on U937 cell growth and its mechanism.

METHODSCell cycle was detected by flow cytometry (FCM), expressions of cell cycle associated protein and the p27 related protein were detected by Western blot. The binding of P27 and Skp2 was detected by immunoprecipitation.

RESULTSFCM displayed that ATRA could inhibit the proliferation of U937 cells. At 72 h on 1 micromol/L ATRA treatment, 72% of the cells were arrested at G0/G1 phase. Western blot displayed that ATRA could decrease the expression of cyclin A, up-regulate the expression of p21 and p27, and down-regulate the expression of p27 related proteins Skp2. p27 could bind with Skp2 in U937 cells as detected by immunoprecipitation.

CONCLUSIONATRA may arrest the proliferation of U937 cells through the reduction of Skp2 expression, and finally the induction of the accumulation of p27.

Cell Cycle ; drug effects ; Cell Proliferation ; drug effects ; Cyclin-Dependent Kinase Inhibitor p27 ; metabolism ; Humans ; S-Phase Kinase-Associated Proteins ; metabolism ; Tretinoin ; pharmacology ; U937 Cells

OBJECTIVETo study the expression of S phase kinase associated protein 2 (Skp2), phosphatase and tensin homolog deleted on chromosome ten (PTEN) in human laryngeal carcinoma and precancerous lesions, to explore their relations and clinical significance.

METHODSFormalin-fixed and paraffin-embedded tissues from 79 cases of laryngeal carcinoma, 16 cases of atypical hyperplasia of vocal fold,14 cases of adult laryngeal papillomas and 27 cases of vocal cord polyps were evaluated for the expression of Skp2, PTEN by SP immunohistochemistry, the levels of these proteins in tissues with the different types of lesion and their correlation with clinicopathological parameters of laryngeal carcinoma were analyzed.

RESULTSThe expression rates of Skp2 in vocal cord polyps, adult laryngeal papillomas, atypical hyperplasia of vocal cord and laryngeal carcinoma were 11. 11% ,14. 29% ,37. 50% ,39. 24% respectively. There was significant difference among them( Hc = 11. 57, P <0. 01). The expression rates of PTEN protein in vocal cord polyps,adult laryngeal papillomas, atypical hyperplasia of vocal cord and laryngeal carcinoma were 100% ,92. 86% ,75. 00%, 56. 96% respectively . There was significant difference among them (Hc = 62. 86, P<0. 05). There was a negative correlation between the expression of Skp2 and PTEN,and their correlation coefficient was r = -0. 4512(P <0. 01). Patients with Skp2 expression in laryngeal carcinoma revealed poorer five yeas survival rate than patients with negative expression of Skp2 (x2 = 21. 46, P = 0. 000).

CONCLUSIONSThe expression of Skp2 and PTEN took important roles in the tumorigenesis, aggressiveness, metastases of laryngeal carcinoma. The high expression of Skp2 was negative correlation with the lower PTEN in laryngeal carcinoma, which suggested that PTEN may regulate the expression of Skp2.

Adult ; Aged ; Aged, 80 and over ; Carcinoma ; pathology ; Female ; Humans ; Laryngeal Neoplasms ; metabolism ; pathology ; Male ; Middle Aged ; PTEN Phosphohydrolase ; metabolism ; S-Phase Kinase-Associated Proteins ; metabolism

OBJECTIVETo study the expression of Skp2 gene (s-phase kinase associated protein 2) in the pathological scars and its relationship with p27kip1 level and to investigate its role and its probable mechanism in the pathogenesis of abnormal scars.

METHODSImmunohistochemical technique was performed to detect the expression and distribution of Skp2 and p27kip1 protein in hypertrophic scar (42 cases), keloid (18 cases), normal scar (40 cases) and normal skin (50 cases), statistics was used to analyze the data.

RESULTSThe positive rate of Skp2 and p27kip1 protein expression was not statistically different between the hypertrophic scar and keloid (P > 0.05), while they were all remarkably significant in comparison between normal scar and abnormal scar (P < 0.05). In pathological scar the protein of Skp2 and p27kip1 showed a strong inverse correlation (P < 0.01).

CONCLUSIONThe result indicated that the expression of Skp2 was increased and it may lead to decrease p27kip1 level in the hypertrophic scar and keloid, Skp2 overexpression might play an important role in the proliferation of fibroblasts and in the pathogenesis of pathological scar by adjusting the regulation of cyclins such as p27kip1.

Adolescent ; Adult ; Child ; Child, Preschool ; Cicatrix, Hypertrophic ; metabolism ; pathology ; Cyclin-Dependent Kinase Inhibitor p27 ; Female ; Humans ; Intracellular Signaling Peptides and Proteins ; metabolism ; Keloid ; metabolism ; pathology ; Male ; Middle Aged ; S-Phase Kinase-Associated Proteins ; metabolism ; Young Adult

BACKGROUND/AIMS: Ligands for peroxisome proliferator-activated receptor gamma (PPAR gamma), a member of the ligand-activated nuclear receptor superfamily, exhibit anti-tumoral effects and are associated with de novo synthesis of proteins involved in regulating the cell cycle and cell survival/death. Helicobacter pylori (H. pylori) is an etiologic agent for gastric adenocarcinoma, and raises the cell turnover of gastric epithelium. The aim of this study was to investigate the effect of PPAR gamma ligand rosiglitazone on the cell proliferation and the expressions of p27 and Skp2 protein in H. pylori infected gastric epithelial cells. METHODS: We examined the expression of PPAR gamma by Western blot in H. pylori infected AGS human gastric epithelial cells. The effect of rosiglitazone on the survival of H. pylori infected AGS cells was assessed by cell viability assay. After the treatment of rosiglitazone in H. pylori infected AGS cells, the expressions of p27 and Skp2 were assessed by Western blot. RESULTS: The expression of PPAR gamma protein was increased in H. pylori infected AGS cells. Cell growth was inhibited and decreased in dose- and time- dependent manner in H. pylori infected AGS cells treated with rosiglitazone. A decrease in Skp2 expression and a reciprocal increase in p27 expression were found in dose- and time-dependent manner in H. pylori infected AGS cells treated with rosiglitazone. CONCLUSIONS: Rosiglitazone inhibited the growth of H. pylori infected AGS cells. Rosiglitazone attenuated Skp2 expression, thereby promoting p27 accumulation in H. pylori infected human gastric epithelial cells. Further studies will be needed to find the effects of accumulation on cell turnover in H. pylori infection and the role in the H. pylori-associated gastric carcinogenesis.
Anti-Bacterial Agents/*pharmacology ; Cell Line ; Cell Proliferation ; Cyclin-Dependent Kinase Inhibitor p27/*metabolism ; Epithelial Cells/metabolism/*microbiology ; Gastric Mucosa/cytology/metabolism/*microbiology ; *Helicobacter pylori ; Humans ; PPAR gamma/antagonists &inhibitors/metabolism ; S-Phase Kinase-Associated Proteins/*metabolism ; Thiazolidinediones/*pharmacology

OBJECTIVETo investigate the expression variation and significance of Skp2 and p27(kip1) during the proliferation of lymphoma cell line Jurkat cells.

METHODSThe binding of p27(kip1) and Skp2 in Jurkat cells were detected by immunoprecipitation. Jurkat cells were treated with serum starvation and release synchronization. The expression variation and subcellular localization of p27(kip1) and Skp2 were detected by subcellular fractionation, Western blot and double immunofluorescence labelling.

RESULTSThe results of immunoprecipitation suggested that p27(kip1) and Skp2 could bind each other in Jurkat cells. During the proliferation of Jurkat cells, the protein expression of p27(kip1) decreased and intranuclear p27(kip1) decreased significantly, while the Skp2 protein increased and cytoplasmic Skp2 increased significantly.

CONCLUSIONDuring the proliferation of Jurkat cells, the increased cytoplasmic synthesis of Skp2 may speed up p27(kip1) degradation via the ubiquitin-proteasome pathway, then intranuclear p27(kip1) decreases significantly, leading to an increased cell cycling activity.

Cell Nucleus ; metabolism ; Cell Proliferation ; Cyclin-Dependent Kinase Inhibitor p27 ; metabolism ; Cytoplasm ; metabolism ; Humans ; Jurkat Cells ; Lymphoma, B-Cell ; metabolism ; pathology ; Protein Binding ; S-Phase Kinase-Associated Proteins ; metabolism

Adult ; Aged ; Aged, 80 and over ; Breast Neoplasms ; metabolism ; pathology ; Carcinoma ; metabolism ; pathology ; Cyclin-Dependent Kinase Inhibitor p27 ; metabolism ; Female ; Humans ; Lymphatic Metastasis ; Middle Aged ; Neoplasm Staging ; Phosphorylation ; Prognosis ; S-Phase Kinase-Associated Proteins ; metabolism ; Threonine ; metabolism

OBJECTIVETo detect the expression of skp2 and p27kip1 in human renal cell carcinoma (RCC) using tissue chip technique, and evaluate the relationship between the proteins and the biological behavior of RCC.

METHODSTissue chip technique and immunohistochemical SP method was used to detect the expression of skp2 and p27kip1 in normal and tumor tissues.

RESULTSThe positivity rate of Skp2 in RCC was significantly higher than that in normal renal tissues (P=0.025). The positivity rate of Skp2 expression in RCC was significantly correlated to poor differentiation of the tumor (P=0.002), and was not associated with the patients gender, age, tumor size, lymph node metastasis and stages of RCC (P>0.05). The positivity rate of p27kip1 in RCC was significantly lower than that in normal renal tissues (P=0.007). The positivity rate of p27kip1 expression was inversely correlated to the malignancy and stage of RCC (P<0.05), but not with the patients' age, gender, lymph node metastasis and tumor size (P>0.05). An inverse correlation was noted between Skp2 and p27kip1 expressions (r= -0.273, P=0.014).

CONCLUSIONOverexpression of Skp2 protein may lead to decreased p27kip1 level in RCC, indicating its involvement in the carcinogenesis and development of RCC.

Adult ; Aged ; Carcinoma, Renal Cell ; metabolism ; pathology ; Cyclin-Dependent Kinase Inhibitor p27 ; biosynthesis ; Female ; Humans ; Immunohistochemistry ; Kidney Neoplasms ; metabolism ; pathology ; Male ; Middle Aged ; S-Phase Kinase-Associated Proteins ; biosynthesis ; Tissue Array Analysis ; Young Adult

OBJECTIVETo determine the expression of Skp2 in different prostate cancer (PCa) cell lines and tissues, and explore its influence on the androgen receptor (AR) signaling pathway and development of castration-resistant prostate cancer (CRPC).

METHODSThe expression levels of Skp2 and AR in different PCa cell lines were detected by Western blot. After knockdown of Skp2 in the C4-2 and 22RV1 cells transfected with shRNA, the expressions of AR and P27 were determined and the activity of ARR3-Luc measured by dual-luciferase reporter gene assay following treatment with dihydrotestosterone (DHT). The expressions of AR and Skp2 in human naïve PCa or CRPC specimens were detected by immunohistochemical staining followed by analysis of their differences and correlation.

RESULTSThe Skp2 protein expression level was significantly higher in the C4-2 or 22RV1 cells than in the LNCaP cells. DHT treatment increased the expression of Skp2 in the C4-2 cells, but knock-down of Skp2 significantly up-regulated the expression of the well-known downstream protein P27 and down-regulated that of AR. Consistently, DHT treatment increased the activity of ARR3-Luc, while knockdown of Skp2 remarkably decreased it in the C4-2 and 22RV1 cells (P < 0.05). In addition, significantly higher expressions of Skp2 and AR were observed in the CRPC than in the naïve specimens (P < 0.05), with a positive correlation between the two proteins (r = 0.658 1, P < 0.05).

CONCLUSIONSkp2 can enhance the expression and transcription activity of the AR protein in CRPC cells or tissues and is promising to be a critical molecular therapeutic target.

Androgens ; pharmacology ; Cell Line, Tumor ; Dihydrotestosterone ; pharmacology ; Disease Progression ; Gene Knockdown Techniques ; Humans ; Male ; Neoplasm Proteins ; genetics ; metabolism ; Prostatic Neoplasms, Castration-Resistant ; metabolism ; Receptors, Androgen ; genetics ; metabolism ; S-Phase Kinase-Associated Proteins ; physiology ; Transcriptional Activation ; Up-Regulation

OBJECTIVE: To study the expression of SKP2 and MRP-1/CD9 protein in glottic cancer and adjacent tissues, and to analyze its significance for a safe surgical margin. METHOD: Thirty-eight cases of glottic squamous cell carcinoma were studied for its cancer tissue, tissue 2 mm, 5 mm, and 10 mm away from cancer, and 10 cases of vocal cord polyp were served as control. SKP2 and MRP-1/CD9 protein were examined by immunohistochemical method. RESULT: The positive expression of SKP2 proteins decreased in sequence of polyp mucosa, those adjacent to carcinoma (10 mm, 5 mm, 2 mm ) and cancer tissue, and there was significant difference between them (P < 0.05); On the contrary, the positive expression of the MRP-1/CD9 proteins increased in sequence of polypous mucosa, those adjacent to carcinoma (10 mm, 5 mm, 2 mm) and cancer tissue,and there was significant difference between them (P < 0.05). CONCLUSION SKP2 and MRP-1/CD may act as the reference index for judging the biological specialty of LSCC. It is appropriate to regard 5 mm or above 5 mm away from tumors as a safe margin for surgical treatment of glottic carcinoma.
Adult ; Aged ; Antigens, CD ; metabolism ; Female ; Glottis ; pathology ; Humans ; Laryngeal Neoplasms ; metabolism ; pathology ; Male ; Membrane Glycoproteins ; metabolism ; Middle Aged ; Neoplasm Staging ; Neoplasms, Squamous Cell ; metabolism ; pathology ; S-Phase Kinase-Associated Proteins ; metabolism ; Tetraspanin 29