[Regulatory Mechanism of Mangiferin Combined with Bortezomib on Malignant Biological Behavior of Burkitt Lymphoma and Its Effect on Expression of CXC Chemokine Receptors]

OBJECTIVE

To analyze the effects of mangiferin combined with bortezomib on the proliferation, invasion, apoptosis and autophagy of human Burkitt lymphoma Raji cells, as well as the expression of CXC chemokine receptors (CXCRs) family, and explore the molecular mechanism between them to provide scientific basis for basic research and clinical work of Burkitt lymphoma.

METHODS

Raji cells were intervened with different concentrations of mangiferin and bortezomib alone or in combination, then cell proliferation was detected by CCK-8 assay, cell invasion ability was detected by Transwell chamber method, cell apoptosis was detected by Annexin V/PI double-staining flow cytometry, apoptosis, autophagy and Akt/mTOR pathway protein expression were detected by Western blot, and the expression changes of CXCR family was detected by real-time quantitative PCR (RT-qPCR).

RESULTS

Different concentrations of mangiferin intervened Raji cells for different time could inhibit cell viability in a concentration- and time-dependent manner (r =-0.682, r =-0.836). When Raji cells were intervened by combination of mangiferin and bortezomib, compared with single drug group, the proliferation and invasion abilities were significantly decreased, while the apoptosis level was significantly increased (P <0.01). Mangiferin combined with bortezomib could significantly up-regulate the expression of pro-apoptotic protein Bax and down-regulate the expression of anti-apoptotic protein Bcl-2 after intervention in Raji cells. Caspase-3 was also hydrolyzed and activated, and then induced the apoptosis of Raji cells. Mangiferin combined with bortezomib could up-regulate the expression of LC3Ⅱ protein in Raji cells, and the ratio of LC3Ⅱ/LC3Ⅰ in cells was significantly up-regulated compared with single drug or control group (P <0.01). Mangiferin combined with bortezomib could significantly inhibit the phosphorylation levels of Akt and mTOR, inhibit the proliferation and invasion of Raji cells by inhibiting Akt/mTOR pathway, and induce cell autophagy and apoptosis. Mangiferin and bortezomib could down-regulate the expressions of CXCR4 and CXCR7 mRNA after single-agent intervention in Raji cells, and the down-regulations of CXCR4 and CXCR7 mRNA expression were more significant when the two drugs were combined (P <0.01). Mangiferin alone or combined with bortezomib had no significant effect on CXCR5 mRNA expression in Raji cells (P >0.05), while the combination of the two drugs could down-regulate the expression of CXCR3 (P <0.05).

CONCLUSION

Mangiferin combined with bortezomib can synergistically inhibit the proliferation and invasion of Raji cells, and induce autophagy and apoptosis. The mechanism may be related to the inhibition of Akt/mTOR signaling pathway, down-regulation of anti-apoptotic protein Bcl-2 and up-regulation of pro-apoptotic protein Bax, and the inhibition of the expression of CXCR family.

[Experimental Study on the Mechanism of Mangiferin Inhibiting Malignant Biological Characteristics of Multiple Myeloma and Exerting Anticancer Effect]

OBJECTIVE

To investigate the effect of pure Chinese herbal extract Mangiferin on the malignant biological behaviors of multiple myeloma (MM) cells, and to analyze the molecular mechanism of the anti-myeloma effect of Mangiferin, so as to provide experimental basis for MM replacement therapy.

METHODS

U266 and RPMI8226 of human MM cell lines were intervened with different concentrations of Mangiferin. Cell proliferation was detected by CCK-8 method. Annexin V/PI double staining flow cytometry was used to detect cell apoptosis. Western blot was used to detect the expression of apoptosis and related signaling pathway proteins, and real-time quantitative polymerase chain reaction (qRT-PCR) was used to detect the expression of matrix metalloproteinase (MMP) and CXC chemokine receptor (CXCR) family.

RESULTS

Mangiferin could inhibit the proliferation activity of U266 and RPMI8226 cells and induce cells apoptosis. After Mangiferin intervened in U266, RPMI8226 cells for 48 h, the expression of Bcl-2 family pro-apoptotic protein Bax was up-regulated, while the expression of survivin and Bcl-xL proteins was down-regulated and caspase-3 was hydrolyzed and activated to promote cell apoptosis, besides, the expression of Bcl-2 protein in U266 cells was also significantly down-regulated to induce apoptosis (P<0.05). After Mangiferin intervenes in MM cells, it can not only increase the expression level of tumor suppressor p53, but also induce programmed cell death of MM cells by inhibiting the expression of anti-apoptotic molecules and down-regulating the phosphorylation levels of AKT and NF-κB. In addition, after the intervention of Mangiferin, the expressions of CXCR4, MMP2 and MMP9 in U266 cells were down-regulated (P<0.05), while there is no effect on the expressions of CXCR2, CXCR7 and MMP13 (P>0.05). However, the expressions of CXCR4, MMP9, and MMP13 in RPMI8226 cells were down-regulated (P<0.01), the expression of MMP2 was weakly affected, and the expression of CXCR2 and CXCR7 was basically not affected (P>0.05).

CONCLUSION

Mangiferin can inhibit the proliferation and induce apoptosis of MM cells, and its mechanism may be related to inhibiting the activation of NF-κB signaling pathway, affecting the expression of Bcl-2 family proteins, and inhibiting the expression of core members of MMP and CXCR family.

[The Effects and Regulatory Mechanism of Targeting CXC Chemokine Receptor 1/2 Combined with Ara-C on the Malignant Biological Behaviors of U937 Cells of Acute Myeloid Leukemia]

OBJECTIVE

To investigate and analyze the effect of CXC chemokine receptor 1/2 (CXCR1/2) targeting inhibitor Reparixin combined with cytarabine (Ara-C) on the malignant biological behaviors of acute myeloid leukemia cells and its effect on the expression of the CXCR family, while exploring the accompanying molecular mechanism, providing scientific basis and reference for new molecular markers and targeted therapy for AML.

METHODS

Acute myeloid leukemia U937 cells were treated with different concentrations of Reparixin, Ara-C alone or in combination, and the cell morphology was observed under an inverted microscope; Wright-Giemsa staining was used to detect cell morphological changes; CCK-8 method was used to detect cell proliferation; the ability of cell invasion was detected by Transwell chamber method; the ability of colony formation was detected by colony formation assay; cell apoptosis was detected by Hoechst 33258 fluorescent staining and Annexin V/PI double-staining flow cytometry; monodansylcadaverine(MDC) staining was used to detect cell autophagy; the expression of apoptosis, autophagy and related signaling pathway proteins was detected by Western blot and the expression changes of CXCR family were detected by real-time quantitative polymerase chain reaction (qRT-PCR).

RESULTS

Reparixin could inhibit the proliferation, invasion, migration and clone formation ability of U937 cells. Compared with the single drug group, when U937 cells were intervened by Reparixin combined with Ara-C, the malignant biological behaviors such as proliferation, invasion and colony formation were significantly decreased, and the levels of apoptosis and autophagy were significantly increased (P<0.01). After Reparixin combined with Ara-C intervenes in U937 cells, it can up-regulate the expression of the pro-apoptotic protein Bax and significantly down-regulate the expression of the anti-apoptotic protein Bcl-2, and also hydrolyze and activate Caspase-3, thereby inducing cell apoptosis. Reparixin combined with Ara-C could up-regulate the expressions of LC3Ⅱ and Beclin-1 proteins in U937 cells, and the ratio of LC3Ⅱ/LC3Ⅰ in cells was significantly up-regulated compared with single drug or control group (P<0.01). MDC result showed that the green granules of vesicles increased significantly, and a large number of broken cells were seen (P<0.01). Reparixin combined with Ara-C can significantly inhibit the phosphorylation level of PI3K, AKT and NF-κB signaling molecule, inhibit the malignant biological behavior of cells by inhibiting the activation of PI3K/AKT/NF-κB pathway, and induce programmed cell death. Ara-C intervention in U937 cells had no effect on the expression of CXCR family (P>0.05). The expression of CXCR1, CXCR2, and CXCR4 mRNA could be down-regulated by Reparixin single-agent intervention in U937 cells (P<0.05), and the expression of CXCR2 was more significantly down-regulated than the control group and other CXCRs (P<0.01). When Reparixin and Ara-C intervened in combination, the down-regulated levels of CXCR1 and CXCR2 were more significant than those in the single-drug group (P<0.01), while the relative expressions of CXCR4 and CXCR7 mRNA had no significant difference compared with the single-drug group (P>0.05).

CONCLUSION

Reparixin combined with Ara-C can synergistically inhibit the malignant biological behaviors of U937 cells such as proliferation, invasion, migration and clone formation, and induce autophagy and apoptosis. The mechanism may be related to affecting the proteins expression of Bcl-2 family and down-regulating the proteins expression of CXCR family, while inhibiting the PI3K/AKT/NF-κB signaling pathway.