The regulatory role of Annexin 3 in a nude mouse bearing a subcutaneous xenograft of MDA-MB-231 human breast carcinoma.

The following study investigated the effects of Annexin A3 (ANXA3) on breast cancer biological behavior in vivo, using nude mouse model bearing a subcutaneous tumor. A total of 18 female nude mice were randomly divided into three groups (n = 6): negative control group which was inoculated with MDA-MB-231 cells, blank control group which was inoculated with MDA-MB-231-NC cells, and the transfection group which was inoculated with MDA-MB-231-Sh cells. The experiment lasted for 4 weeks, during which mice conditions, diet and defecation were monitored on a daily basis. Body weight, as well as tumor diameters, which were assessed using standard caliper method, were measured once a week. In vivo imaging was performed to detect the activity of transplanted tumors. H&E staining was used to analyze the histological structure of tumor tissues in three groups, while flow cytometry and fluorescent RT-PCR were performed to measure cell proliferation and the expression of ANXA3 mRNA. Briefly, significantly slower tumor growth and tumor activity were observed in the transfection group compared to negative and blank controls, while the tumor weight and volume in this group were also significantly lower compared to the other two groups (P < 0.01). Sparse tumor cells accompanied with massive fibrous connective tissue proliferation, and lower new blood vessels formation were observed in transfection group compared to other groups. Moreover, mRNA and protein levels of ANXA3 were significantly lower in transfection group compared to the other two groups (P < 0.01). In addition, lower proliferation index and higher G0/1 cell count were observed in transfection group compared to negative and blank controls (P < 0.01). To sum up, these results suggested that ANXA3 silencing regulates the proliferation and inhibits the growth of MDA-MB-231 breast cancer cells. Consequently, ANXA3 might be used as a potential target for gene therapy in breast cancer.

Effects of PHA-665752 and Cetuximab Combination Treatment on In Vitro and Murine Xenograft Growth of Human Colorectal Cancer Cells with KRAS or BRAF Mutations.

BACKGROUND: It remains unknown whether blockade of c-Met signaling and epidermal growth factor receptor signaling is effective in suppressing the growth of human colorectal cancer (CRC) cells. In this study, we investigated the effects of the c-Met inhibitor PHA-665752 alone and in combination with cetuximab on the growth of human CRC cells in vitro and in mouse xenografts. METHODS: Human CRC cell lines (Caco2, HCT-116, and HT-29) and mice bearing HCT-116 xenografts were treated with cetuximab in the absence or presence of PHA-665752. Cell viability and apoptosis were examined using the MTT and TUNEL assays, respectively. Vimentin was measured by immunohistochemistry as a marker for epithelial-to-mesenchymal transition. Western blotting was used to determine signaling protein expression levels. RESULTS: The MTT assay showed that the growth of Caco2, HCT-116, and HT-29 cells was inhibited by PHA-665752 in a dose-dependent manner, but only Caco2 cell growth was suppressed by cetuximab. Combination treatment with PHA-665752 and cetuximab inhibited the proliferation of Caco2 cells and RAS mutant CRC cell lines. However, relative to the PHA-665752-alone treatment group, HT-29 cells with a BRAF mutation showed no noticeable effect. The mean tumor volume in mice treated with cetuximab in combination with PHA-665752 was significantly smaller than that in the mice treated with only cetuximab (P = 0.033) or PHA-665752 (P < 0.01). Similarly, the expression of vimentin in the mice treated with PHA-665752 in combination with cetuximab was significantly lower than that in the mice treated with cetuximab or PHA-665752 alone (P < 0.05 in each case). TUNEL assays revealed that treatment with PHA-665752 in combination with cetuximab markedly increased CRC cell apoptosis. Western blotting analysis of signaling protein expression showed that PHA- 665752 inhibited Met phosphorylation (P < 0.05). In addition, treatment with cetuximab alone or in combination with PHA-665752 effectively inhibited EGFR phosphorylation (P < 0.05). CONCLUSION: Combination treatment with PHA-665752 and cetuximab suppressed in vitro and in vivo CRC cell growth more than treatment with either agent alone did.

The effect of childbirth on carcinogenesis of DMBA-induced breast cancer in female SD rats.

Many epidemiologic and clinical studies have indicated that the frequency of breast cancer was lower in parous women than in nulliparous women. Moreover, the incidence of breast cancer has been reported to be lower in women with early childbirth than in women with late childbirth. To verify the effect of childbirth and the age at first childbirth on carcinogenesis and progression of breast cancer, we induced breast cancer by 7,12-dimethylbenanthracene (DMBA) in 120 female Sprague-Dawley (SD) rats, and divided them into control or experimental (DMBA-treated) nulliparous, early childbirth, and late childbirth groups to observe the incidence, latency, and size of breast cancer. Argyrophilic nucleolar organizer regions (AgNOR) count and the expression of C-erbB-2, proliferating cell nuclear antigen (PCNA), Ki-67, and minichromosome maintenance protein 2 (MCM2) in breast cancer tissues were detected by immunohistochemistry. The breast cancer incidences were 95.0%, 16.7%, and 58.8% in the experimental nulliparous, early childbirth, and late childbirth groups, respectively (all P < 0.05). Between any two of these groups, the latency was significantly different, but tumor size was similar. AgNOR count and the expression of C-erbB-2, PCNA, Ki-67, and MCM2 were significantly higher in the experimental nulliparous group than in the experimental early or late childbirth groups (P < 0.05), but no significant differences were observed between the latter two groups. Taken together, the results suggest that childbirth, especially early childbirth, can reduce the incidence and postpone the onset of DMBA-induced breast cancer.