S1. Apoptosis detected by TUNEL in MDA-MB-231 cells expressing shSEMA4C or EV. S2. Sema4C cDNA re-expressed in these MDA-MB-231 siSEMA4C cells could recover cell growth and ANG and CSF secretion. S3. Expression of senescence-associated pathway proteins in MDA-MB-231 cells were examined using western blot post-transfection at the indicated time. S4. SEMA4C regulates angiogenesis. S5. The vascular integrity was detected in EV tumours and shSEMA4C tumours. S6. Sections from tumors were immunostained with anti-cd45 (white arrowhead) or F4/80(black arrow) antibody. S7. SEMA4C regulates macrophage recruitment. S8. The vascular density and macrophage area were detected in EV tumours and shSEMA4C tumours at the same weight. S9. Recombinant soluble Sema4C did not affect MDA-MB-231 proliferation and endothelial cells tube formation despite could increase macrophages migration. S10. mRNA levels of ANG and CSF were analyzed in presence of siSEMA4C RNA or sema4C cDNA in MDA-MB-231cells. S11. Expression of mRNA(A) and secreted protein(B) level of ANG and CSF-1 were detected in the MCF-7 cells overexpressing SEMA4C. S12. The growth curve and cell cycle were detected in presence of siANG in MDA-MB-231 cells.
Funding
Technical Innovation Special Project of Hubei Province
Ningbo Natural Science Foundation of China
National Science and Technology Major
ARTICLE ABSTRACT
Semaphorins are a large family of evolutionarily conserved morphogenetic molecules that are associated with repelling axonal guidance. Intriguingly, recent researches indicate that semaphorins are involved in cancer progression. Semaphorin 4C (SEMA4C) has long been considered a neuronal migration gene, but we detected that it is also highly expressed in many malignant human cancers. During an investigation of subcutaneous tumor models, we found that SEMA4C expression promoted tumor growth and progression. We discovered that SEMA4C was involved in maintaining tumor cell self-renewal, likely by regulating the p53 pathway. Inhibiting the expression of endogenous SEMA4C in tumor cells impaired growth and induced senescence and cell-cycle arrest in the G2-phase. In addition, we found that SEMA4C induced the production of angiogenin and colony-stimulating factor-1 (CSF-1) in tumor cells by activating the NF-κB pathway in a plexinB2-dependent manner. In conclusion, SEMA4C expression in breast cancer cells promotes cancer cell proliferation, macrophage recruitment, and angiogenesis. Thus, inhibition of SEMA4C activity may be a novel therapeutic strategy for human breast cancer.
In breast cancer, therapeutic targeting of the SEMA4C pathway may prevent tumor growth, angiogenesis, metastasis, and progression.
