The expressions of p21 and pRB may be good indicators for the sensitivity of esophageal squamous cell cancers to CPT-11: Cell proliferation activity correlates with the effect of CPT-11

Simvastatin enhances irinotecan-induced apoptosis in human non-small cell lung cancer cells by inhibition of proteasome activity

Simvastatin, a potent inhibitor of 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMG-CoA) is known to stimulate apoptotic cell death and induce cell cycle arrest through inhibition of proteasome. The purpose of this study is to investigate whether simvastatin would be synergistic with irinotecan against human non-small cell lung cancer (NSCLC) cells. Antitumor effect was measured by growth inhibition of cells and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. The cytotoxic interaction between irinotecan and simvastatin was assessed using the combination index. Effects on cell cycle distribution and apoptosis were determined by flow cytometry and DNA fragmentation. Proteasome activity was measured by ELISA quantification of 20S proteasome. NF-κB activation was determined using TransAM™ NF-κB p65 Transcription Factor Assay Kit. IκB-α was measured by immunoblot. A combination of irinotecan with simvastatin showed significantly enhanced cell growth inhibition compared with irinotecan alone, which resulted in a synergistic cytotoxicity. Irinotecan and simvastatin combination treatment of A549 and H460 cells increased G(1) phase arrest, which was associated with up-regulation of p21(WAF1/CIP) and p53 compared with irinotecan alone. In addition, simvastatin combination treatment increased irinotecan-related apoptosis as determined by fluorescence microscopy and flow cytometric analysis. We also found that combination therapy showed superior proteasome inhibitory activity leading to effectively suppress NF-κB transcription factor activation. Consistently, this effect was associated with up-regulation of IκB-α. These findings suggest that simvastatin enhances irinotecan-induced apoptosis in human NSCLC cells through inhibition of proteasome activity.

Prognostic impact of array-based genomic profiles in esophageal squamous cell cancer

BACKGROUND

Esophageal squamous cell carcinoma (ESCC) is a genetically complex tumor type and a major cause of cancer related mortality. Although distinct genetic alterations have been linked to ESCC development and prognosis, the genetic alterations have not gained clinical applicability. We applied array-based comparative genomic hybridization (aCGH) to obtain a whole genome copy number profile relevant for identifying deranged pathways and clinically applicable markers.

METHODS

A 32 k aCGH platform was used for high resolution mapping of copy number changes in 30 stage I-IV ESCC. Potential interdependent alterations and deranged pathways were identified and copy number changes were correlated to stage, differentiation and survival.

RESULTS

Copy number alterations affected median 19% of the genome and included recurrent gains of chromosome regions 5p, 7p, 7q, 8q, 10q, 11q, 12p, 14q, 16p, 17p, 19p, 19q, and 20q and losses of 3p, 5q, 8p, 9p and 11q. High-level amplifications were observed in 30 regions and recurrently involved 7p11 (EGFR), 11q13 (MYEOV, CCND1, FGF4, FGF3, PPFIA, FAD, TMEM16A, CTTS and SHANK2) and 11q22 (PDFG). Gain of 7p22.3 predicted nodal metastases and gains of 1p36.32 and 19p13.3 independently predicted poor survival in multivariate analysis.

CONCLUSION

aCGH profiling verified genetic complexity in ESCC and herein identified imbalances of multiple central tumorigenic pathways. Distinct gains correlate with clinicopathological variables and independently predict survival, suggesting clinical applicability of genomic profiling in ESCC.

Differential antiproliferative effects of calcitriol on tumor-derived and matrigel-derived endothelial cells

The most active metabolite of vitamin D, calcitriol, is growth inhibitory for various tumor types in vitro and in vivo and inhibits the growth of endothelial cells freshly isolated from tumors [tumor-derived endothelial cells (TDEC)]. We compared the effects of calcitriol on Matrigel-derived endothelial cells (MDEC) and TDEC isolated from Matrigel plugs and squamous cell carcinoma tumors, respectively. TDEC and MDEC expressed vitamin D receptor (VDR) and responded to calcitriol by increasing VDR protein expression. Although no mutations were found in VDR from either cell type, Scatchard plot analysis revealed a higher ligand-binding affinity in TDEC (K(d), 0.26 nmol/L) than MDEC (K(d), 0.65 nmol/L). The VDR signaling axis in both cells was intact as shown using nuclear translocation and 24-hydroxylase promoter-luciferase reporter assays. However, unlike TDEC, MDEC were resistant to calcitriol-induced growth inhibition. Calcitriol (10 nmol/L) resulted in a 12.3% growth inhibition of MDEC compared with 47% in TDEC. In TDEC, calcitriol resulted in induction of G(0)/G(1) arrest (10.75%) and reduction of S-phase cells (6.8%) with induction of p27 and down-regulation of p21 protein expression. Apoptotic effects, determined by Annexin V staining were also observed in calcitriol-treated TDEC (38.6%). Calcitriol caused reduced expression of p-Erk and p-Akt and an increase of poly(ADP-ribose) polymerase and caspase-3 cleavage in TDEC. By contrast, none of these effects on cell cycle or apoptosis were seen in calcitriol-treated MDEC. These results show that TDEC were more sensitive than MDEC to the antiproliferative effects of calcitriol despite apparently normal VDR content and structure of signaling axis in both cell types.

Relationship between proliferative activity of cancer cells and clinicopathological factors in patients with esophageal squamous cell carcinoma

AIM: To assess whether the molecular markers of malignant tumors could improve the understanding of tumor charact-eristics, and to observe the characteristics of expression of cell cycle markers Ki-67 and cyclin A in esophageal carcinoma and to analyze the relationship between proliferative activity of cancer cells and clinicopathological factors.

METHODS: Seventy of surgically resected esophageal squamous cell carcinoma (SCC) were examined by immun-ohistochemistry utilizing commercially available antibodies. Nuclear staining was regarded as a positive result. At least 50 fields in each tumor and non-tumor section were evaluated at a medium power (×200) to determine the proportion of tumor cells and the staining intensity of nuclei in the entire sections.

RESULTS: Ki-67 and cyclin A were only expressed in base cells of normal esophageal mucosa. The positive immuno-staining of nuclei of SCC was significantly higher than that in normal esophageal mucosa (t = 13.32 and t = 7.52, respectively, P<0.01). The distribution of positively stained was more diffuse and stronger in poorly differentiated SCC. Both Ki-67 and cyclin A expressions were related to histological grades of tumors (t = 3.5675 and t = 3.916; t = 2.13, respectively, P<0.05) but not to the sex and age of the patients, tumor size, lymphatic invasion, location, or stage grouping.

CONCLUSION: The proliferative activity of cancer cells may be understood by immunohistochemistry of Ki-67 and cyclin A in Chinese patients with esophageal SCC. These cell cycle markers may serve as an indicator of cancer cell proliferation rate. The overexpression of cell cycle markers Ki-67 and cyclin A suggests the poor SCC differentiation in patients with esophageal carcinoma.