Efficacy of punarnavine in restraining organ-specific tumour progression in 4T1-induced murine breast tumour model

Most of the breast cancer deaths occur when cancer cells depart from their tumour of origin and spread systemically and colonise distant organs. The present study was to find out whether punarnavine, the quinolizidine alkaloid, with already proven antimetastatic effect on spontaneous B16F10 pulmonary metastasis has got any effect on a drastic organ-specific breast cancer spread. For the study, we selected a syngenic mouse 4T1 breast tumour model that mimics stage four of human breast cancer. The metastatic progression of 4T1 to lymph nodes, lungs, and liver was reduced by punarnavine (40 mg/kg body weight) administration in BALB/c mice. This was evident from the histopathology of these organs as well as from the reduction in the metastatic cell density of cultured 6-thioguanine-resistant 4T1 cells in the punarnavine-treated group compared to the control group. There was also a significant (p < 0.0001) inhibition of the primary breast tumour growth in the orthotopic site of induction with a simultaneous increase (p < 0.0001) in the life span of treated animals. The assessment of biochemical parameters such as hydroxyproline, hexosamine, uronic acid, sialic acid and γ-glutamyl transferase and the analysis of various cytokines VEGF, IL-1β, TNF-α and GM-CSF showed a similar pattern of reduction in punarnavine (p < 0.0001) treated group compared to the control group. The gene expression study revealed the inhibitory effect of punarnavine on the major genes MMP-2, MMP-9, TIMP-1, TIMP-2 and VEGF involved in the metastatic process. These findings undeniably proved the potential of this quinolizidine alkaloid in combating breast tumour development and its progression in the studied murine model.