Anti-cancer and anti-angiogenic effects of partially purified lectin from Praecitrullus fistulosus fruit on in vitro and in vivo model

Praecitrullus fistulosus, belonging to the family of Cucurbitaceae is a tropical vegetable and medicinal plant, grown and consumed extensively in subtropical countries, including the subcontinent India. However, there are limited reports on the medicinal properties of the plant and need to be explored. The lectin identified from the fruit sap of Praecitrullus fistulosus, named as PfLP, possesses potent agglutinating activity against trypsinized rabbit erythrocytes and exhibited its functional role against tumor progression, on in vitro & in vivo models. Experimental results revealed that PfLP shows a promising cytotoxic effect against multiple cancer cell lines. Further, we examined the in vivo anticancer and anti-angiogenic properties of PfLP against EAC bearing mice. PfLP treatment resulted in tumor growth inhibition and increased the life-span of the EAC bearing mice, without showing any detectable side effects, as revealed by histological parameters. Further, a significant decrease in the ascites VEGF secretion level was parallel with a drastic reduction in tumoral neovasculature as evidence for angiogenic parameters. Gelatin zymogram study reveals that PfLP inhibits metalloproteinases (MMP-2 & MMP-9) activity in order to execute its anti-angiogenic effect. PfLP has also inducing apoptosis, in cancer cells was revealed by DNA fragmentation assay followed by Giemsa and AO/EBr staining method, showed the apoptotic bodies and condensed nuclei compared to control cells. More interestingly, PfLP did not exhibit any adverse side effects or secondary complications in normal mice. These results clearly exhibit the potential role of PfLP in regressing the tumor progression by targeting angiogenesis and inducing cell death in mouse transplantable tumor.