Cinobufagin modulates vasculogenic mimicry and tumor-associated macrophages to inhibit ovarian cancer progression

Background: Ovarian cancer is among the most prevalent malignant tumors affecting women. While conventional therapies like surgery do provide some measure of disease control, they are accompanied by evident side effects that may readily result in drug resistance. Cinobufagin (HCS) is a water-soluble active component extracted from the dried skin of the Bufo gargarizans. Clinical studies have demonstrated its significant anti-tumor effects.

Methods: Transcriptome sequencing identified Forkhead Box S1 (FOXS1)-related targets, and Western blot analysis evaluated the expression levels of vasculogenic mimicry (VM)-related proteins and pathway proteins after cinobufagin intervention. Immunofluorescence and ELISA were used to detect the effects of cinobufagin on M1 and M2 macrophage markers. Additionally, a co-culture model of Skov3 cells and macrophages was established to study the effects of cinobufagin on tumor-associated macrophage polarization.

Results: Cinobufagin significantly inhibited the growth of Skov3 ovarian cancer cells both in vitro and in vivo. Additionally, cinobufagin decreased the expression levels of VM-related proteins, thereby affecting vasculogenesis both in vitro and in vivo. Transcriptomic analysis revealed that the regulation of the FOXS1 gene contributed to this inhibitory effect. In the co-culture system, we found that cinobufagin inhibited IL-4-induced M2 macrophage polarization. Overexpression of FOXS1 in Skov3 cells enhanced the activity of the C-C motif chemokine ligand 2/receptor 2 (CCL2/CCR2) pathway, which was suppressed by cinobufagin, thus affecting the tumor microenvironment.

Conclusion: Cinobufagin suppressed vasculogenic mimicry by regulating the FOXS1 gene and inhibited M2 macrophage polarization through the CCL2/CCR2 pathway, thereby affecting the tumor microenvironment.