Purpose: This study was aimed to investigate the underlying mechanism of B7-H3 induced ovarian cancer proliferation and drugs resistance.
Materials and methods: We compared the expression of B7-H3 in ovarian tumor tissues from high-malignant or low-malignant patients by immunohistochemistry. We established B7-H3 overexpression and knockout ovarian cells by CRISPR-Cas9 technology and examined the expression of the PI3K/AKT/BCL-2 signals in tumor cells by Western blot or immunofluorescence. We detected the B7-H3 overexpression ovarian cancer cells drugs resistance by CCK8 cell proliferation analysis and Annexin V/PI staining. Tumor-bearing mice were used to investigate the anticancer effects of PI3K/AKT inhibitors in combination with B7-H3 neutralizing antibodies.
Results: Enhanced expression of B7-H3 was observed in ovarian tumor tissues from high-malignant patients compared to those from low-malignant patients. Notably, B7-H3 overexpression caused enhanced cells proliferation and chemo-resistance in vitro and in vivo through the activation of PI3K/AKT signaling pathways and up-regulation of BCL-2 protein. Combination of chemotherapeutic agents and B7-H3 neutralizing antibodies efficiently reverses the drugs resistance induced by B7-H3, resulting in improved anticancer effects in ovarian cancer.
Conclusion: B7-H3 expression induces the activation the PI3K/AKT signaling pathway and up-regulates BCL-2 in protein level, resulting in the sustained growth and chemo-resistance in ovarian cancer. Blockade of B7-H3 signals efficiently reverses the chemo-resistance, which provides an innovative target in ovarian cancer treatment.
Keywords: B7-H3, CD276, PI3K, AKT, BCL-2, ovarian cancer