Cell Cycle Control Related Proteins (p53,p21, and Rb) and Transforming Growth Factorβ(TGFβ) in Benign and Carcinomatous (In Situ and Infiltrating) Human Breast: Implications in Malignant Transformations

Anti-tumor effects of the histone deacetylase inhibitor vorinostat on canine urothelial carcinoma cells

Canine urothelial carcinoma (cUC) is the most common tumor of the lower urinary tract in dogs. Although chemotherapy and radical surgery have improved the overall survival, most dogs with cUC succumb to metastasis or recurrence. Therefore, the development of an effective systematic therapy is warranted. In this study, a comprehensive drug screening test using a cUC cell line was performed and the anti-tumor effect of a histone deacetylase (HDAC) inhibitor was evaluated. Comprehensive drug screening was performed on cUC cells. Based on this screening, the anti-proliferation effect of vorinostat, an HDAC inhibitor clinically applied in humans, was evaluated using several cUC cell lines in sulforhodamine B and flow cytometry assays. Western blot analysis was also performed to evaluate the degree of acetylation of histone H3 as well as the expression and phosphorylation of cell cycle-related molecules. The anti-tumor effect of vorinostat in vivo was evaluated using a xenograft model. Finally, immunohistochemistry was performed on acetyl-histone H3 in cUC and the relationship between the degree of acetylation and prognosis was examined using Kaplan–Meier survival analysis. Drug screening revealed that HDAC inhibitors consistently inhibited the growth of cUC cells. Vorinostat inhibited the growth of 6 cUC cell lines in a dose-dependent manner and induced G0/G1 cell cycle arrest. Western blot analysis showed that vorinostat mediated the acetylation of histone H3, the dephosphorylation of p-Rb, and the upregulation of p21 upon exposure to vorinostat. Furthermore, inhibition of tumor growth was observed in the xenograft model. In clinical cUC cases, neoplastic urothelium showed significant deacetylation of histones compared to the normal control, where lower histone acetylation levels were associated with a poor prognosis. In conclusion, the therapeutic potential of vorinostat was demonstrated in cUC. Histone deacetylation may be related to cUC tumor progression.

Cell cycle arrest and induction of apoptosis by cajanin stilbene acid from Cajanus cajan in breast cancer cells

BACKGROUND

The low abundant cajanin stilbene acid (CSA) from Pigeon Pea (Cajanus cajan) has been shown to kill estrogen receptor α positive cancer cells in vitro and in vivo. Downstream effects such as cell cycle and apoptosis-related mechanisms have not been analyzed yet.

MATERIAL AND METHODS

We analyzed the activity of CSA by means of flow cytometry (cell cycle distribution, mitochondrial membrane potential, MMP), confocal laser scanning microscopy (MMP), DNA fragmentation assay (apoptosis), Western blotting (Bax and Bcl-2 expression, caspase-3 activation) as well as mRNA microarray hybridization and Ingenuity pathway analysis.

RESULTS

CSA induced G2/M arrest and apoptosis in a concentration-dependent manner from 8.88 to 14.79 µM. The MMP broke down, Bax was upregulated, Bcl-2 downregulated and caspase-3 activated. Microarray profiling revealed that CSA affected BRCA-related DNA damage response and cell cycle-regulated chromosomal replication pathways.

CONCLUSION

CSA inhibited breast cancer cells by DNA damage and cell cycle-related signaling pathways leading to cell cycle arrest and apoptosis.

Favorable modulation of benign breast tissue and serum risk biomarkers is associated with > 10 % weight loss in postmenopausal women

We conducted a phase II feasibility study of a 6-month behavioral weight loss intervention in postmenopausal overweight and obese women at increased risk for breast cancer and the effects of weight loss on anthropomorphic, blood, and benign breast tissue biomarkers. 67 women were screened by random peri-areolar fine-needle aspiration, 27 were registered and 24 participated in the interventional phase. The 24 biomarker evaluable women had a median baseline BMI of 34.2 kg/m(2) and lost a median of 11 % of their initial weight. Significant tissue biomarker modulation after the 6-month intervention was noted for Ki-67 (if restricted to the 15 women with any Ki-67 at baseline, p = 0.041), adiponectin to leptin ratio (p = 0.003); and cyclin B1 (p = 0.001), phosphorylated retinoblastoma (p = 0.005), and ribosomal S6 (p = 0.004) proteins. Favorable modulation for serum markers was observed for sex hormone-binding globulin (p < 0.001), bioavailable estradiol (p < 0.001), bioavailable testosterone (p = 0.033), insulin (p = 0.018), adiponectin (p = 0.001), leptin (p < 0.001), the adiponectin to leptin ratio (p < 0.001), C-reactive protein (p = 0.002), and hepatocyte growth factor (p = 0.011). When subdivided by <10 or >10 % weight loss, change in percent total body and android (visceral) fat, physical activity, and the majority of the serum and tissue biomarkers were significantly modulated only for women with >10 % weight loss from baseline. Some factors such as serum PAI-1 and breast tissue pS2 (estrogen-inducible gene) mRNA were not significantly modulated overall but were when considering only those with >10 % weight loss. In conclusion, a median weight loss of 11 % over 6 months resulted in favorable modulation of a number of anthropomorphic, breast tissue and serum risk and mechanistic markers. Weight loss of 10 % or more should likely be the goal for breast cancer risk reduction studies in obese women.

Induction of G1 arrest and apoptosis in human cancer cells by crebanine, an alkaloid from Stephania venosa

In this study, we focused the effects of crebanine, an alkaloid isolated from the tuber of Stephania venosa, on various human cancer cells. Crebanine treatment was found to significantly inhibit the proliferation of human leukemic cells (HL-60, U937 and K562), human fibrosarcoma cells (HT1080) and cervix cancer cell lines (KB-3-1 and KB-V1), of which HL-60 cells were the most sensitive to its treatment. In contrast, crebanine caused much less toxicity in human normal fibroblast cells. Our results demonstrated that crebanine mediated cell cycle arrest at G0/G1 phase and this was associated with down-regulation of cyclins A and D. In addition, crebanine induced apoptosis, which was detected by observation of the membrane phospholipid exposure in flow cytometry. Its induction of apoptosis was accompanied by an increase in cleavage of caspase-3, -8, -9 and poly(ADP-ribose) polymerase (PARP), and was attributable to the augmentation of Bax/Bcl proteins level. Crebanine also decreased mitochondrial membrane potential. Taken together, crebanine exerts anti-proliferative effects on human cancer cells through the induction of cell cycle arrest at the G1 phases and apoptosis. Our results suggest that crebanine is a promising new candidate as a chemotherapeutic agent for cancer therapy.

Comparison of molecular strategies for breast cancer virotherapy using oncolytic adenovirus

Oncolytic viruses are regulated by the tumor phenotype to replicate and lyse cancer cells selectively. To identify optimal strategies for breast cancer we compared five adenoviruses with distinct regulatory mechanisms: Ad-dl922-947 (targets G1-S checkpoint); Ad-Onyx-015 and Ad-Onyx-017 (target p53/mRNA export); Ad-vKH1 (targets Wnt pathway), and AdEHE2F (targets estrogen receptor/G1-S checkpoint/hypoxic signaling). The quantity of virus required to kill 50% of breast cancer cells after 6 days (EC(50), plaque-forming units per cell) was measured. The most potent virus was Ad-dl922-947 (EC(50), 0.01-5.4 in SkBr3, MDA-231, MDA-468, MCF7, and ZR75.1 cells), followed by wild-type (Ad-WT; EC(50), 0.3-5.5) and AdEHE2F (EC(50), 1.4-3.9). Ad-vKH1 (EC(50), 7.2-72.1), Ad-Onyx-017 (EC(50), 8.4-167), and Ad-Onyx-015 (EC(50), 17.7-377) showed less activity. Most viruses showed limited cytotoxicity in normal human cells, including breast epithelium MCF10A (EC(50), >722) and fibroblasts (EC(50), >192) and only moderate cytotoxicity in normal microvascular endothelial cells (HMVECs; EC(50), 42.8-149), except Ad-dl922-947, which was active in HMVECs (EC(50), 1.6). After injection into MDA-231 xenografts, Ad-WT, AdEHE2F, and Ad-dl922-947 showed replication, assessed by hexon staining and quantitative polymerase chain reaction measurement of viral DNA, and significantly inhibited tumor growth, leading to extended survival. After intravenous injection Ad-dl922-947 showed DNA replication (233% of the injected dose was measured in liver after 3 days) whereas AdEHE2F did not. Overall, AdEHE2F showed the best combination of low toxicity in normal cells and high activity in breast cancer in vitro and in vivo, suggesting that molecular targeting using estrogen response elements, hypoxia response elements, and a dysregulated G1-S checkpoint is a promising strategy for virotherapy of breast cancer.

Homozygous deletion of glycogen synthase kinase 3beta bypasses senescence allowing Ras transformation of primary murine fibroblasts

In primary mammalian cells, expression of oncogenes such as activated Ras induces premature senescence rather than transformation. We show that homozygous deletion of glycogen synthase kinase (GSK) 3beta (GSK3beta-/-) bypasses senescence induced by mutant Ras(V12) allowing primary mouse embryo fibroblasts (MEFs) as well as immortalized MEFs to exhibit a transformed phenotype in vitro and in vivo. Both catalytic activity and Axin-binding of GSK3beta are required to optimally suppress Ras transformation. The expression of Ras(V12) in GSK3beta-/-, but not in GSK3beta+/+ MEFs results in translocation of beta-catenin to the nucleus with concomitant up-regulation of cyclin D1. siRNA-mediated knockdown of beta-catenin decreases both cyclin D1 expression and anchorage-independent growth of transformed cells indicating a causal role for beta-catenin. Thus Ras(V12) and the lack of GSK3beta act in concert to activate the beta-catenin pathway, which may underlie the bypass of senescence and tumorigenic transformation by Ras.

Vaccination with p53 peptide-pulsed dendritic cells is associated with disease stabilization in patients with p53 expressing advanced breast cancer; monitoring of serum YKL-40 and IL-6 as response biomarkers

p53 Mutations are found in up to 30% of breast cancers and peptides derived from over-expressed p53 protein are presented by class I HLA molecules and may act as tumor-associated epitopes in cancer vaccines. A dendritic cell (DC) based p53 targeting vaccine was analyzed in HLA-A2+ patients with progressive advanced breast cancer. DCs were loaded with 3 wild-type and 3 P2 anchor modified HLA-A2 binding p53 peptides. Patients received up to 10 sc vaccinations with 5 x 10(6) p53-peptide loaded DC with 1-2 weeks interval. Concomitantly, 6 MIU/m(2) interleukine-2 was administered sc. Results from a phase II trial including 26 patients with verified progressive breast cancer are presented. Seven patients discontinued treatment after only 2-3 vaccination weeks due to rapid disease progression or death. Nineteen patients were available for first evaluation after 6 vaccinations; 8/19 evaluable patients attained stable disease (SD) or minor regression while 11/19 patients had progressive disease (PD), indicating an effect of p53-specific immune therapy. This was supported by: (1) a positive correlation between p53 expression of tumor and observed SD, (2) therapy induced p53 specific T cells in 4/7 patients with SD but only in 2/9 patients with PD, and (3) significant response associated changes in serum YKL-40 and IL-6 levels identifying these biomarkers as possible candidates for monitoring of response in connection with DC based cancer immunotherapy. In conclusion, a significant fraction of breast cancer patients obtained SD during p53-targeting DC therapy. Data encourage initiation of a randomized trial in p53 positive patients evaluating the impact on progression free survival.

Influence of IFN-gamma and its receptors in human breast cancer

BACKGROUND

Interferons are a group of proteins that trigger multiple responses including prevention of viral replication, inhibition of cell growth, and modulation of cell differentiation. In different mammary carcinoma cell lines IFNgamma induces growth arrest at mid-G1. At the present there are no in vivo studies in human breast. The aim of this study was to investigate the expression patterns of IFNgamma and its two receptors (IFNgamma-Ralpha and IFNgamma-Rbeta) by Western blot and immunohistochemistry, in order to elucidate its role in the different types of human breast cancer (in situ and infiltrative).

METHODS

Immunohistochemical and semiquantitative study of IFNgamma, its receptors types (IFNgamma-Ralpha and IFNgamma-Rbeta), cell proliferation (proliferating cell nuclear antigen, also named PCNA), and apoptosis (TUNEL method) was carried between the three breast groups (fibrocystic lesions, in situ tumors and infiltrating tumors).

RESULTS

In the three groups of patients, IFNgamma and IFNgamma-Ralpha immunoreactions appeared in the cytoplasm while IFNgamma-Rbeta also was found in the nucleus. The optical density to IFNgamma was higher in in situ carcinoma than in benign and infiltrating tumors. When we observed IFNgamma-Ralpha, the optical density was lower in infiltrating carcinoma than in benign and in situ tumors (the higher density). To IFNgamma-Rbeta, the optical density was similar in the three group samples. In tumor samples PCNA and TUNEL index was significantly higher; than in benign diseases. PCNA index increased with the malignance. No significant differences were found between cancer types to TUNEL. IFNgamma could be a potential therapeutic tool in breast cancer. However, tumor cells are able to escape from the control of this cytokine in the early tumor stages; this is probably due to a decreased expression of IFNgamma, or also to an alteration of either its receptors or some transduction elements.

CONCLUSION

We conclude that the decrease in the % positive samples that expressed IFNgamma and IFNgamma-Ralpha together with the nuclear localization of IFNgamma-Rbeta, could be a tumoral cell response, although perhaps insufficient to inhibit the uncontrolled cell proliferation. Perhaps, IFNgamma might be unable to activate p21 to stop the cell cycle, suggesting a possible participation in breast cancer development.

Role of tumor necrosis factor-alpha and its receptors in human benign breast lesions and tumors (in situ and infiltrative)

The aim of the present study was to characterize the expression pattern of tumor necrosis factor (TNF)-alpha and its receptors in breast samples (benign diseases, in situ carcinomas and infiltrating carcinomas), and to compare these results with those obtained previously for interleukin-6, p53 and p21 using the same samples in order to elucidate the effects of these cytokines on the proliferation-apoptosis equilibrium. Immunoexpression of TNF-alpha and its receptors (TNFRI and TNFRII) were studied by western blotting and immunohistochemistry. The percentage of samples positive for TNF-alpha and TNFRII was higher in in situ carcinoma than in benign breast diseases, and TNFRII was even higher in infiltrating tumors. The percentage of samples positive for TNFRI was similar in the three groups. For the three proteins and in the three patient groups, immunoreactions were observed in the peripheral cytoplasm. In the positive samples, immunostaining for TNF-alpha was more intense in infiltrating tumors than in the other two patient groups, whereas immunostaining for both receptors was higher in in situ carcinoma than in benign breast diseases, and even higher in infiltrating tumors. Comparing the TNF-alpha results with previous results for mtp53, p21 and interleukin-6, we found an association between the expression of these four proteins and increasing malignancy. TNF-alpha might be an important factor in breast cancer promotion as its proliferation and survival effects seems to be enhanced through the increased expression of TNFRII. Also, the pro-apoptotic pathway of TNFRI could be inhibited by p21 (which appeared increased in breast cancer), altering TNFRI effects in promoting the expression of several factors, such interleukin-6, which contribute to tumor promotion.