Endometrial cancer: The management of high-risk disease

Knockdown of PLC-gamma-2 and calmodulin 1 genes sensitizes human cervical adenocarcinoma cells to doxorubicin and paclitaxel

Background

RNA interference (RNAi) is a powerful approach in functional genomics to selectively silence messenger mRNA (mRNA) expression and can be employed to rapidly develop potential novel drugs against a complex disease like cancer. However, naked siRNA being anionic is unable to cross the anionic cell membrane through passive diffusion and therefore, delivery of siRNA remains a major hurdle to overcome before the potential of siRNA technology can fully be exploited in cancer. pH-sensitive carbonate apatite has recently been developed as an efficient tool to deliver siRNA into the mammalian cells by virtue of its high affinity interaction with the siRNA and the desirable size distribution of the resulting siRNA-apatite complex for effective cellular endocytosis. Moreover, internalized siRNA was found to escape from the endosomes in a time-dependent manner and efficiently silence gene expression.

Results

Here we show that carbonate apatite-mediated delivery of siRNA against PLC-gamma-2 (PLCG2) and calmodulin 1 (CALM1) genes has led to the sensitization of a human cervical cancer cell line to doxorubicin- and paclitaxel depending on the dosage of the individual drug whereas no such enhancement in cell death was observed with cisplatin irrespective of the dosage following intracellular delivery of the siRNAs.

Conclusion

Thus, PLCG2 and CALM1 genes are two potential targets for gene knockdown in doxorubicin and paclitaxel-based chemotherapy of cervical cancer.

High-risk endometrial carcinoma profiling identifies TGF-β1 as a key factor in the initiation of tumor invasion

Endometrial cancer is among the three most common cancers in females in industrialized countries. In the majority of cases, the tumor is confined to the uterus at the time of diagnosis and presents a good prognosis. However, after primary surgery, 15% to 20% of these tumors recur and have limited response to systemic therapy. We carried out gene expression profiling of high-risk recurrence endometrial cancers to identify new therapeutic approaches targeting the molecular pathways involved in the acquisition of an aggressive tumor phenotype. A microarray gene-expression analysis on a total of 51 human endometrial carcinomas revealed 77 genes specifically altered in high-risk recurrence tumors (P < 0.001). The bioinformatics analysis of gene-gene interactions and molecular relationships among these genes pointed to a prominent role for TGF-β1 signaling in the acquisition of an aggressive phenotype. We further showed that TGF-β1 has a principal role at the initiation of endometrial carcinoma invasion through the promotion of the epithelial to mesenchymal transition that leads to the acquisition of an invasive phenotype in HEC-1A and RL95-2 cells. Impairment of this initial step with SB-431542, a specific TGF-β1 inhibitor, precluded further persistent endometrial carcinoma invasion. In conclusion, we showed that the characterization of the molecular changes associated with the acquisition of an aggressive phenotype represents a realistic strategy for the rational identification and characterization of new potential therapeutic targets in an effort to improve the clinical management and the outcome of high-risk endometrial cancer patients.

Two estrogen-related variants in CYP19A1 and endometrial cancer risk: a pooled analysis in the Epidemiology of Endometrial Cancer Consortium

Common variants in CYP19A1 (the A alleles of rs749292 and rs727479) have been associated with a 10% to 20% increase in circulating estrogen levels in postmenopausal women. We hypothesized that the presence of one or both A alleles in these single nucleotide polymorphisms (SNP) is associated with increased endometrial cancer risk. We tested this hypothesis in a large pooled analysis of 4,998 endometrial cancer cases and 8,285 controls from 10 studies in the Epidemiology of Endometrial Cancer Consortium. The majority of women (>66%) were whites, with smaller proportions of other races and ethnic groups (blacks, Asians, and Latinas) also included in this pooled analysis. Unconditional logistic regression was used to model the association between SNPs/haplotypes and endometrial cancer risk. Carrying the A allele of either of these SNPs was associated with an increased risk of endometrial cancer, with pooled odds ratios per allele of 1.14, 95% confidence interval of 1.09-1.21, and P = 7.1 x 10(-7) for rs749292, and odds ratio per allele of 1.08, 95% confidence interval of 1.02-1.14, and P = 0.009 for rs727479. For rs749292, these associations were generally stronger among women age >or=55 years. For both SNPs, risk increased with increasing body mass index, and for rs727479, this pattern seemed stronger among women age >or=55 years (P interaction = 0.007). The combination of A alleles in the two SNPs, either by direct count or by haplotype analysis, did not increase risk above that observed for the individual SNPs. Our study provides evidence that CYP19A1 genetic variation influences susceptibility to endometrial cancer, particularly among older and obese women.

Accuracy of preoperative endometrial sampling for the detection of high-grade endometrial tumors

OBJECTIVE

This study was undertaken to evaluate the ability of preoperative endometrial sampling to accurately diagnose high-grade endometrial tumors.

STUDY DESIGN

Three hundred sixty endometrial cancer patients had preoperative endometrial sampling and hysterectomy specimens that underwent pathologic review at a single institution from 1995 to 2005. The sensitivity of Pipelle and curettage to diagnose high-grade endometrial tumors (grade 3 endometrioid adenocarcinoma, serous carcinoma, carcinosarcoma, clear cell carcinoma) was determined. Agreement between preoperative and hysterectomy diagnoses was measured by the Kappa statistic.

RESULTS

Sensitivity of Pipelle and curettage was 93.8% and 97% in patients with low-grade cancer and 99.2% and 100% in patients with high-grade cancer. Good agreement was observed between the preoperative and the hysterectomy histologic diagnoses (Kappa = 0.69), and between the preoperative and hysterectomy tumor grade (Kappa=0.78).

CONCLUSION

Preoperative endometrial sampling with Pipelle or curettage is sensitive and accurate for the diagnosis of high-grade endometrial tumors, including tumors with nonendometrioid histology.