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Silencing of CXCR4 sensitizes triple-negative breast cancer cells to cisplatin.

Liang S, Peng X, Li X, Yang P, Xie L, Li Y, Du C, Zhang G - Oncotarget (2015)

Bottom Line: We found that CXCR4 silencing significantly inhibited cell growth, decreased colony formation, and enhanced cisplatin sensitivity while overexpression of CXCR4 rendered cells more resistant to cisplatin.Moreover, the percentage of apoptosis and cell cycle arrest at the G2/M phase of cisplatin-treated CXCR4 knockdown cells was significantly higher than control cells.However overexpression of CXCR4 had the reverse effect.

View Article: PubMed Central - PubMed

Affiliation: Department of Breast Medical Oncology, Cancer Hospital of Shantou University Medical College, Shantou 515031, PR China.

ABSTRACT
Triple-negative breast cancer (TNBC) is an aggressive form of breast cancer for which there is no effective treatment. Previously, we and others demonstrated that CXCR4 surface expression is an independent prognostic factor for disease relapse and survival in breast cancer. In this study, we investigated the effects of CXCR4 gene silencing on cisplatin chemosensitivity in human triple-negative breast cancer cell lines. We found that CXCR4 silencing significantly inhibited cell growth, decreased colony formation, and enhanced cisplatin sensitivity while overexpression of CXCR4 rendered cells more resistant to cisplatin. Moreover, the percentage of apoptosis and cell cycle arrest at the G2/M phase of cisplatin-treated CXCR4 knockdown cells was significantly higher than control cells. Furthermore, we demonstrated CXCR4 knockdown cells showed lower levels of mutant p53 and Bcl-2 protein than the control group, while also having higher levels of caspase-3 and Bax. However overexpression of CXCR4 had the reverse effect. In vivo experiments confirmed that downregulation of CXCR4 enhanced cisplatin anticancer activity in tumor-bearing mice, and that this enhanced anticancer activity is attributable to tumor cell apoptosis. Thus, this study indicates that CXCR4 can modulate cisplatin sensitivity in TNBC cells and suggests that CXCR4 may be a therapeutic target for TNBC.

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Effects of cisplatin on proliferation and colony formation in triple-negative breast cancer (TNBC) cells(A) CXCR4 knockdown and CXCR4 overexpression cells were treated with cisplatin for 48 h. The effect of CXCR4 on cisplatin sensitivity was measured by MTT assay. (B) IC50 values for cisplatin in MDA-MB-231 and MDA-MB-468 cells for 48 h were calculated by regression analysis using SPSS software based on the results of the MTT assays. (C) Colony formation of MDA-MB-231-NC and MDA-MB-231-shCXCR4 cells following treatment with cisplatin (0, 0.1 and 1 μM) for 48 h. (D) Colony formation of MDA-MB-468-NC and MDA-MB-468-CXCR4 cells following treatment with cisplatin (0, 0.1 and 1 μM) for 48 h. (E) The percentage of colony formation of MDA-MB-231 and MDA-MB-468 cells treatment with cisplatin. Data are represented as the mean ± SD of triplicate determinations. Each assay was performed in triplicate and repeated at least three times. *p < 0.05, **p < 0.01, as compared with untreated cells.
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Figure 1: Effects of cisplatin on proliferation and colony formation in triple-negative breast cancer (TNBC) cells(A) CXCR4 knockdown and CXCR4 overexpression cells were treated with cisplatin for 48 h. The effect of CXCR4 on cisplatin sensitivity was measured by MTT assay. (B) IC50 values for cisplatin in MDA-MB-231 and MDA-MB-468 cells for 48 h were calculated by regression analysis using SPSS software based on the results of the MTT assays. (C) Colony formation of MDA-MB-231-NC and MDA-MB-231-shCXCR4 cells following treatment with cisplatin (0, 0.1 and 1 μM) for 48 h. (D) Colony formation of MDA-MB-468-NC and MDA-MB-468-CXCR4 cells following treatment with cisplatin (0, 0.1 and 1 μM) for 48 h. (E) The percentage of colony formation of MDA-MB-231 and MDA-MB-468 cells treatment with cisplatin. Data are represented as the mean ± SD of triplicate determinations. Each assay was performed in triplicate and repeated at least three times. *p < 0.05, **p < 0.01, as compared with untreated cells.

Mentions: Suppression of CXCR4 increased sensitivity to cisplatin-mediated growth inhibition compared with the same cells transfected with empty vector (Figure 1A). Increased growth inhibition compared with MDA-MB-231-NC cells was observed at cisplatin concentrations of 10 and 20 μM. The half-maximal inhibitory concentration (IC50) (Figure 1B) at 48 h was 16.07 ± 1.77 μM and 32.43 ± 1.21 μM for MDA-MB-231-shCXCR4 and MDA-MB-231-NC cells, respectively (p = 0.000), indicating that CXCR4 knockdown increases sensitivity to cisplatin. Consistent with this, we found that it was more resistant to cisplatin in CXCR4 overexpression MDA-MB-468-CXCR4 cells than MDA-MB-468-NC cells. The IC50 at 48 h was 39.92 ± 1.8 μM and 13.73 ± 0.75 μM for MDA-MB-468-CXCR4 and MDA-MB-468-NC cells, respectively (p = 0.000, Figure 1B). In a colony formation assay, knockdown of CXCR4 inhibited MDA-MB-231 colony formation, whereas overexpression of CXCR4 stimulated MDA-MB-468 colony formation compared to the control (Figure 1C–1E). In addition, cisplatin effectively inhibited colony formation of these cells in a dose-dependent manner (p = 0.000). These results suggest that CXCR4 might be involved in the regulation of cell proliferation.


Silencing of CXCR4 sensitizes triple-negative breast cancer cells to cisplatin.

Liang S, Peng X, Li X, Yang P, Xie L, Li Y, Du C, Zhang G - Oncotarget (2015)

Effects of cisplatin on proliferation and colony formation in triple-negative breast cancer (TNBC) cells(A) CXCR4 knockdown and CXCR4 overexpression cells were treated with cisplatin for 48 h. The effect of CXCR4 on cisplatin sensitivity was measured by MTT assay. (B) IC50 values for cisplatin in MDA-MB-231 and MDA-MB-468 cells for 48 h were calculated by regression analysis using SPSS software based on the results of the MTT assays. (C) Colony formation of MDA-MB-231-NC and MDA-MB-231-shCXCR4 cells following treatment with cisplatin (0, 0.1 and 1 μM) for 48 h. (D) Colony formation of MDA-MB-468-NC and MDA-MB-468-CXCR4 cells following treatment with cisplatin (0, 0.1 and 1 μM) for 48 h. (E) The percentage of colony formation of MDA-MB-231 and MDA-MB-468 cells treatment with cisplatin. Data are represented as the mean ± SD of triplicate determinations. Each assay was performed in triplicate and repeated at least three times. *p < 0.05, **p < 0.01, as compared with untreated cells.
© Copyright Policy - open-access
Related In: Results  -  Collection

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Figure 1: Effects of cisplatin on proliferation and colony formation in triple-negative breast cancer (TNBC) cells(A) CXCR4 knockdown and CXCR4 overexpression cells were treated with cisplatin for 48 h. The effect of CXCR4 on cisplatin sensitivity was measured by MTT assay. (B) IC50 values for cisplatin in MDA-MB-231 and MDA-MB-468 cells for 48 h were calculated by regression analysis using SPSS software based on the results of the MTT assays. (C) Colony formation of MDA-MB-231-NC and MDA-MB-231-shCXCR4 cells following treatment with cisplatin (0, 0.1 and 1 μM) for 48 h. (D) Colony formation of MDA-MB-468-NC and MDA-MB-468-CXCR4 cells following treatment with cisplatin (0, 0.1 and 1 μM) for 48 h. (E) The percentage of colony formation of MDA-MB-231 and MDA-MB-468 cells treatment with cisplatin. Data are represented as the mean ± SD of triplicate determinations. Each assay was performed in triplicate and repeated at least three times. *p < 0.05, **p < 0.01, as compared with untreated cells.
Mentions: Suppression of CXCR4 increased sensitivity to cisplatin-mediated growth inhibition compared with the same cells transfected with empty vector (Figure 1A). Increased growth inhibition compared with MDA-MB-231-NC cells was observed at cisplatin concentrations of 10 and 20 μM. The half-maximal inhibitory concentration (IC50) (Figure 1B) at 48 h was 16.07 ± 1.77 μM and 32.43 ± 1.21 μM for MDA-MB-231-shCXCR4 and MDA-MB-231-NC cells, respectively (p = 0.000), indicating that CXCR4 knockdown increases sensitivity to cisplatin. Consistent with this, we found that it was more resistant to cisplatin in CXCR4 overexpression MDA-MB-468-CXCR4 cells than MDA-MB-468-NC cells. The IC50 at 48 h was 39.92 ± 1.8 μM and 13.73 ± 0.75 μM for MDA-MB-468-CXCR4 and MDA-MB-468-NC cells, respectively (p = 0.000, Figure 1B). In a colony formation assay, knockdown of CXCR4 inhibited MDA-MB-231 colony formation, whereas overexpression of CXCR4 stimulated MDA-MB-468 colony formation compared to the control (Figure 1C–1E). In addition, cisplatin effectively inhibited colony formation of these cells in a dose-dependent manner (p = 0.000). These results suggest that CXCR4 might be involved in the regulation of cell proliferation.

Bottom Line: We found that CXCR4 silencing significantly inhibited cell growth, decreased colony formation, and enhanced cisplatin sensitivity while overexpression of CXCR4 rendered cells more resistant to cisplatin.Moreover, the percentage of apoptosis and cell cycle arrest at the G2/M phase of cisplatin-treated CXCR4 knockdown cells was significantly higher than control cells.However overexpression of CXCR4 had the reverse effect.

View Article: PubMed Central - PubMed

Affiliation: Department of Breast Medical Oncology, Cancer Hospital of Shantou University Medical College, Shantou 515031, PR China.

ABSTRACT
Triple-negative breast cancer (TNBC) is an aggressive form of breast cancer for which there is no effective treatment. Previously, we and others demonstrated that CXCR4 surface expression is an independent prognostic factor for disease relapse and survival in breast cancer. In this study, we investigated the effects of CXCR4 gene silencing on cisplatin chemosensitivity in human triple-negative breast cancer cell lines. We found that CXCR4 silencing significantly inhibited cell growth, decreased colony formation, and enhanced cisplatin sensitivity while overexpression of CXCR4 rendered cells more resistant to cisplatin. Moreover, the percentage of apoptosis and cell cycle arrest at the G2/M phase of cisplatin-treated CXCR4 knockdown cells was significantly higher than control cells. Furthermore, we demonstrated CXCR4 knockdown cells showed lower levels of mutant p53 and Bcl-2 protein than the control group, while also having higher levels of caspase-3 and Bax. However overexpression of CXCR4 had the reverse effect. In vivo experiments confirmed that downregulation of CXCR4 enhanced cisplatin anticancer activity in tumor-bearing mice, and that this enhanced anticancer activity is attributable to tumor cell apoptosis. Thus, this study indicates that CXCR4 can modulate cisplatin sensitivity in TNBC cells and suggests that CXCR4 may be a therapeutic target for TNBC.

Show MeSH
Related in: MedlinePlus