Ribosomal S6 protein kinase 4 promotes radioresistance in esophageal squamous cell carcinoma.

Esophageal squamous cell carcinoma (ESCC) is one of the most aggressive cancers and is highly resistant to current treatments. ESCC harbors a subpopulation of cells exhibiting cancer stem-like cell (CSC) properties that contribute to therapeutic resistance including radioresistance, but the molecular mechanisms in ESCC CSCs are currently unknown. Here, we report that ribosomal S6 protein kinase 4 (RSK4) plays a pivotal role in promoting CSC properties and radioresistance in ESCC. RSK4 was highly expressed in ESCC CSCs and associated with radioresistance and poor survival in patients with ESCC. RSK4 was found to be a direct downstream transcriptional target of ΔNp63α, the main p63 isoform, which is frequently amplified in ESCC. RSK4 activated the ß-catenin signaling pathway through direct phosphorylation of GSK-3ß at Ser9. Pharmacologic inhibition of RSK4 effectively reduced CSC properties and improved radiosensitivity in both nude mouse and patient-derived xenograft models. Collectively, our results strongly suggest that the ΔNp63α/RSK4/GSK-3ß axis plays a key role in driving CSC properties and radioresistance in ESCC, indicating that RSK4 is a promising therapeutic target for ESCC treatment.

Blockade of Macrophage CD147 Protects Against Foam Cell Formation in Atherosclerosis.

The persistence of macrophage-derived foam cells in the artery wall fuels atherosclerosis development. However, the mechanism of foam cell formation regulation remains elusive. We are committed to determining the role that CD147 might play in macrophage foam cell formation during atherosclerosis. In this study, we found that CD147 expression was primarily increased in mouse and human atherosclerotic lesions that were rich in macrophages and could be upregulated by ox-LDL. High-throughput compound screening indicated that ox-LDL-induced CD147 upregulation in macrophages was achieved through PI3K/Akt/mTOR signaling. Genetic deletion of macrophage CD147 protected against foam cell formation by impeding cholesterol uptake, probably through the scavenger receptor CD36. The opposite effect was observed in primary macrophages isolated from macrophage-specific CD147-overexpressing mice. Moreover, bioinformatics results indicated that CD147 suppression might exert an atheroprotective effect via various processes, such as cholesterol biosynthetic and metabolic processes, LDL and plasma lipoprotein clearance, and decreased platelet aggregation and collagen degradation. Our findings identify CD147 as a potential target for prevention and treatment of atherosclerosis in the future.

Activation of the NF-κB Pathway and Heterozygous Deletion of TNFAIP3 (A20) Confer Superior Survival in Extranodal Natural Killer/T-Cell Lymphoma, Nasal Type.

OBJECTIVES: To investigate the role of TNFAIP3 deletions and NF-κB activation in extranodal natural killer/T-cell lymphoma (ENKTCL), nasal type. METHODS: In total, 138 patients with ENKTCL were included. Activation of NF-κB pathway and expression of TNFAIP3 (A20) were examined by immunohistochemistry. TNFAIP3 was analyzed for deletions using FICTION (fluorescence immunophenotyping and interphase cytogenetics as a tool for investigating neoplasms), for mutations using Sanger sequencing, and for promoter methylation using methylation-specific sequencing. RESULTS: NF-κB pathway activation was observed in 31.2% of cases (43/138), TNFAIP3 expression was negative in 15.2% of cases (21/138), and heterozygous TNFAIP3 deletion was observed in 35% of cases (35/100). TNFAIP3 exons 2 to 9 mutations and promoter methylation were not observed. Kaplan-Meier analysis showed patients with NF-κB pathway activation or TNFAIP3 heterozygous deletion to have a longer overall survival. CONCLUSIONS: Our study demonstrated that NF-κB activation and TNFAIP3 heterozygous deletion confer superior survival in patients with ENKTCL.

Desmoplastic small round cell tumor of the submandibular gland--a rare but distinctive primary salivary gland neoplasm.

Desmoplastic small round cell tumor is a highly aggressive neoplasm that generally involves the peritoneum and pelvis of young patients. Only rare cases occur outside the abdomen. We report a case presenting as a primary submandibular gland tumor in a 24-year-old man. Histologically, although there were irregular tumor islands lying in an abundant desmoplastic stroma, there were also areas comprising large cellular islands with scanty stroma in between, raising the differential diagnosis of various salivary gland carcinomas. The tumor cells were medium sized, with hyperchromatic nuclei and moderate amounts of cytoplasm. The diagnosis of desmoplastic small round cell tumor was confirmed by the presence of a polyphenotypic immunoprofile (positive for cytokeratin, desmin, and neuron-specific enolase) and the characteristic EWS-WT1 gene fusion. Although rare, desmoplastic small round cell tumor has to be considered in the differential diagnosis of poorly differentiated neoplasms of the salivary gland, especially in young patients.

Angiomatoid fibrous histiocytoma: first report of primary pulmonary origin.

Angiomatoid fibrous histiocytoma is an uncommon soft tissue tumor most frequently affecting the deep dermis and subcutis of the extremities in children and young adults. We report the first case presenting as a primary pulmonary tumor in a 46-year-old man. Histologically, the tumor was composed of multiple cellular nodules surrounded by a fibrous pseudocapsule and peritumoral lymphoplasmacytic infiltrates. The nodules were composed of histiocytoid cells with a diffuse, whorled, or vague storiform pattern, with the intervening areas densely packed with plasma cells and lymphocytes. The tumor cells were immunoreactive for epithelial membrane antigen, and focally desmin, CD68, and CD163. Fluorescence in-situ hybridization revealed EWS gene translocation, which was further confirmed on polymerase chain reaction to result from EWS/ATF1 gene fusion. It is important to recognize that angiomatoid fibrous histiocytoma can occur in the lung because its histologic features are rather nondescript and thus can be mistaken for other tumors such as meningioma, inflammatory myofibroblastic tumor, and follicular dendritic cell sarcoma.

Epigenetic and genetic alterations of PTEN in hepatocellular carcinoma.

AIM: To investigate the roles of epigenetic and genetic alterations of the phosphatase and tensin homologue on chromosome 10 gene (PTEN) in carcinogenesis and the development of hepatocellular carcinomas (HCC). METHODS: A total of 56 cases of HCC tissues and six liver cell lines were studied for the expression of PTEN by immunohistochemistry and Western blot analysis. The PTEN gene mutations in exon5 and exon8 were detected by a combination of single-strand conformation polymorphism (SSCP) analysis and DNA sequencing. Methylation-specific PCR (MSP) was used to identify PTEN promoter methylation. RESULTS: Of the 56 cases of HCC, 24 (42.9%) expressed the PTEN protein. All surrounding liver tissues of the hepatoma (32 cases) were positive for PTEN. Of the six cell lines, three liver cancer cell lines showed a low expression of PTEN. Five mutations of 56 HCC samples were detected. All of them were located at intron4. No mutation was found in exon5 and exon8. After MSP analysis, we found nine cases of PTEN promoter methylation in 56 specimens (16.1%). However, no CpG island of PTEN was found to be methylated in all six liver cell lines. CONCLUSION: The level of PTEN protein was altered in part of the HCC. The downregulation of PTEN expression may not be mainly associated with the PTEN mutations, but partly due to PTEN promoter methylation and other epigenetic regulation.

[Mutations of tumor suppressor gene PTEN mutations in hepatocellular carcinoma and its implications in tumor proliferation and apoptosis].

OBJECTIVE: To study mutations of tumor suppressor gene PTEN in human hepatocellular carcinomas and its effects on the proliferation and apoptosis of hepatocellular carcinoma cell line HHCC. METHODS: (1) PCR-SSCP and sequence analysis were used to detect the mutations of the 5th and 8th exon of PTEN in 42 cases of human primary hepatocellular carcinoma. (2) Eukaryotic expression vectors of the wild-type (pEGFP-wt-PTEN) and the mutant type (pEGFP-PTEN, G129R) of PTEN were constructed. Lipofectamine 2000 mediated gene transfection was used to transfect hepatocellular carcinoma cell line HHCC, in which the PTEN protein is not expressed. Culture medium containing G418 was used to select stable transfectants. MTT colorimetry was used to analyze the proliferation ability of selected cell lines. Naive HHCC cells and HHCC cells transfected with empty vector (pEGFP-C1) served as controls. (3) TNF-alpha was used to induce apoptosis of selected cell clones. RESULTS: (1) Point mutation involving the 5th exon of PTEN was detected in 4 of 42 primary hepatocellular carcinomas. (2) Compared with the control groups, the proliferation of hepatocellular carcinoma cells was significantly inhibited by the transfection of wild-type PTEN gene, while the transfection with mutant PTEN construct did not significantly change the proliferation. (3) The apoptosis indices of cells transfected with the wild-type and the mutant PTEN genes were 13.8% and 8.1% respectively. Compared with the control, the apoptosis index of HHCC cell transfected by the wild type PTEN was significantly lower (P < 0.05). There were no significant differences between HHCC cells transfected with mutated PTEN gene and the control (P > 0.05). The expression of internal 473-phosphorylated Akt of HHCC was weak, but was enhanced when the cells treated with TNF-alpha. However, it was down regulated by the wild type PTEN. CONCLUSIONS: (1) First time report that PTEN mutations can be found in 9.5% human primary hepatocellular carcinomas. (2) The expression of the wild-type PTEN can suppress the proliferation of HHCC cells, and such suppression was lost when PTEN gene was mutated. (3) PTEN inhibition of the proliferation and the enhancement of apoptosis of hepatocellular carcinoma cells is likely related to a down-regulation of the TNF-alpha induced activation of protein kinase Akt pathway.

[Inhibitory effect of tumor suppressor gene PTEN on hepatocellular carcinoma cell line HHCC proliferation and its mechanisms of action].

OBJECTIVE: To study the effect of tumor suppressor gene PTEN on proliferation and cell cycle of hepatocellular carcinoma cell line HHCC. METHODS: Firstly, eukaryotic expression vectors of wild type and mutated type of PTEN gene were constructed, named as pEGFP-WT-PTEN and pEGFP-PTEN; G129R, respectively. Lipofectamine 2000 was used to transfect the constructed expression vectors into hepatocellular carcinoma cell line HHCC which was PTEN protein negative. G418 was used to select the cell clones constantly expressing PTEN protein. Flow cytometry was used to assay the cell cycle of HHCC transfected by above mentioned eukaryotic expression vectors and non-transfected cell line HHCC. Intrinsic 473-phosphorylated AKT representing the level of active AKT was assayed by Western blot. The non-transfected HHCC served as control. RESULTS: The proliferation of HHCC constantly expressing PTEN protein was obviously inhibited compared with HHCC cells transfected with mutated PTEN gene and empty vectors, and non-transfected HHCC cells. The number of HHCC cells transfected with wild type PTEN gene at G(1) phase, G(2) phase and S phase was 70.8%, 6.8% and 22.4%, respectively. Compared with control group transfected with empty vector, the number of G(1) phase HHCC cells constantly expressing wild type-PTEN protein was significantly higher than that of control. The number of cells in G(2) and S phase was significantly lower than that of control. However, the number of cells in G(1) phase, G(2) phase and S phase of HHCC transfected with mutant PTEN was 63.2%, 10.1% and 26.7%, respectively. There was no significant difference compared with control group. Western blot result showed that the intrinsic level of 473-phosphorylated AKT of HHCC constantly expressing wild type PTEN protein was down-regulated, and that of HHCC transfected with mutated PTEN gene was equal to that of control. CONCLUSION: Wild type PTEN gene can inhibit the proliferation of hepatocellular carcinoma cells at G(1) phase. The mechanism is possibly related with intrinsic activity of AKT, which is down-regulated by wild type PTEN.

Expression and significance of a new tumor suppression gene PTEN in primary renal cell carcinoma.

BACKGROUND & OBJECTIVE: PTEN gene is a newly discovered tumor suppressor gene, that maps to chromosome 10q23, and of longstanding interest to those studying somatic mutations in human tumors. Mutation and deletion of PTEN gene probably resulted in a new signal transduction pathway related to human malignant tumors. It was reported that PTEN gene mutated and deleted in renal cell carcinoma, however, there was no report concerning its expression in renal cell carcinoma. This study was designed to investigate expression and significance of PTEN gene in primary renal cell carcinoma. METHODS: Immunohistochemical peroxidase-conjugated streptavidin (SP) method was used to detect expression of PTEN gene in 40 cases of primary renal cell carcinoma, 18 with renal tissues closely adjacent to carcinoma and 5 case of normal renal tissues. The relationship between expression of tumor suppressor gene of PTEN and the percentage of lymph node metastasis of renal cell carcinoma was analyzed. RESULT: It was showed that PTEN gene was expressed in all 5 case of normal renal tissues and 18 cases of renal tissues closely adjacent to carcinoma. The intensity was relatively strong and it was localized mainly in cytoplasm of epithelium cells of renal tubular. Expression of PTEN in 40 cases of renal cell carcinoma were different, 12.5% were negative, 17.5% were weak positive, and 70% were strong positive. PTEN protein was localized in cytoplasm of carcinoma cells. The percentage of lymph node metastasis of renal cell carcinoma negative or weak positive of PTEN protein was 80% and 51.74%, respectively. The percentage of lymph node metastasis of renal cell carcinoma positive of PTEN protein was 10.71%, comparing with those of renal cell carcinoma negative or weak positive of PTEN protein, the difference was significant (P < 0.05). CONCLUSION: This study suggested that PTEN gene was deleted or weakly expressed in primary renal significant cell carcinoma, which is probably related to tumorigenesis and development of renal cell carcinoma.