Enhanced Anti-Cancer Effect of Snake Venom Activated NK Cells on Lung Cancer Cells by Inactivation of NF-κB.

In the present study, we investigated anti-cancer effect of snake venom activated NK cells (NK-92MI) in lung cancer cell lines. We used snake venom (4 µg/ml) treated NK-92MI cells to co-culture with lung cancer cells. There was a further decrease in cancer cell growth up to 65% and 70% in A549 and NCI-H460 cell lines respectively, whereas 30-40% was decreased in cancer cell growth by snake venom or NK-92MI alone treatment. We further found that the expression of various apoptotic proteins such as that Bax, and cleaved caspase-3 as well as the expression of various death receptor proteins like DR3, DR4 and Fas was also further increased. Moreover, consistent with cancer cell growth inhibition, the DNA binding activity of NF-κB was also further inhibited after treatment of snake venom activated NK-92MI cells. Thus, the present data showed that activated NK cells could further inhibit lung cancer cell growth.

Co-culture with NK-92MI cells enhanced the anti-cancer effect of bee venom on NSCLC cells by inactivation of NF-κB.

In the present study we experimented on a multimodal therapeutic approach, such as combining chemotherapy agent (Bee venom) with cellular (NK-92MI) immunotherapy. Previously bee venom has been found to show anti-cancer effect in various cancer cell lines. In lung cancer cells bee venom showed an IC(50) value of 3 µg/ml in both cell lines. The co-culture of NK-92MI cell lines with lung cancer cells also show a decrease in viability upto 50 % at 48 h time point. Hence we used bee venom treated NK-92MI cells to co-culture with NSCLC cells and found that there is a further decrease in cell viability upto 70 and 75 % in A549 and NCI-H460 cell lines respectively. We further investigated the expression of various apoptotic and anti-apoptotic proteins and found that Bax, cleaved caspase-3 and -8 were increasing where as Bcl-2 and cIAP-2 was decreasing. The expression of various death receptor proteins like DR3, DR6 and Fas was also increasing. Concomitantly the expression of various death receptor ligands (TNFalpha, Apo3L and FasL) was also increasing of NK-92MI cells after co-culture. Further the DNA binding activity and luciferase activity of NF-κB was also inhibited after co-culture with bee venom treated NK-92MI cell lines. The knock down of death receptors with si-RNA has reversed the decrease in cell viability and NF-κB activity after co-culture with bee venom treated NK-92MI cells. Thus this new approach can enhance the anti-cancer effect of bee venom at a much lower concentration.

(E)-2,4-bis(p-hydroxyphenyl)-2-butenal has an antiproliferative effect on NSCLC cells induced by p38 MAPK-mediated suppression of NF-κB and up-regulation of TNFRSF10B (DR5).

BACKGROUND AND PURPOSE: The Maillard Reaction Products (MRPs) are known to be effective in chemoprevention. Here we focused on the anticancer effects of (E)-2,4-bis(p-hydroxyphenyl)-2-butenal (a MRP) on human non-small-cell lung cancer (NSCLC) cells and its mechanism of action. EXPERIMENTAL APPROACH: We analysed the activity of (E)-2,4-bis(p-hydroxyphenyl)-2-butenal on NSCLC cells (NCI-H460 and A549) by use of Western blot analysis for major apoptotic proteins, MAPK, NF-κB and death receptor expression. We also used RT-PCR to determine its effects on death receptor mRNA expression, EMSA for effects on NF-κB DNA binding activity and colony formation assay for effects of inhibitors on (E)-2,4-bis(p-hydroxyphenyl)-2-butenal's actions. KEY RESULTS: (E)-2,4-bis(p-hydroxyphenyl)-2-butenal induced a concentration (10-40 µg·mL⁻¹)- and time (30 min-72 h)-dependent inhibitory effect on the growth of NSCLC cells due to induction of apoptosis. Concomitantly, it significantly increased the expression of apoptotic proteins such as cleaved caspase-3, cleaved caspase-9, Bax and p53, but down-regulated the expression of anti-apoptotic proteins Bcl-2, cIAP1 and cIAP2. This effect was induced by up-regulation of MAPK and death receptor proteins TNFRSF12, TNFRSF10B and TNFRSF21, but suppression of NF-κB. Of the death receptors activated, only TNFRSF10B knock down with siRNA reversed the effect of (E)-2,4-bis(p-hydroxyphenyl)-2-butenal. Even though all the MAPKs were activated, only pretreatment with a p38 MAPK inhibitor reversed (E)-2,4-bis(p-hydroxyphenyl)-2-butenal-induced cell growth inhibition, increase in cleaved caspase-3, -9 and TNFRSF10B expression, and NF-κB inactivation. CONCLUSIONS AND IMPLICATIONS: (E)-2,4-bis(p-hydroxyphenyl)-2-butenal induces apoptosis in NSCLC cells by p38 MAPK-mediated suppression of NF-κB and activation of TNFRSF10B, which then activates the caspase-3 and caspase-9 pathways.

Anti-cancer effect of bee venom toxin and melittin in ovarian cancer cells through induction of death receptors and inhibition of JAK2/STAT3 pathway.

We investigated whether bee venom and melittin, a major component of bee venom, inhibit cell growth through enhancement of death receptor expressions in the human ovarian cancer cells, SKOV3 and PA-1. Bee venom (1-5 µg/ml) and melittin (0.5-2 µg/ml) inhibited the growth of SKOV3 and PA-1 ovarian cancer cells by the induction of apoptotic cell death in a dose dependent manner. Consistent with apoptotic cell death, expression of death receptor (DR) 3 and DR6 was increased in both cancer cells, but expression of DR4 was increased only in PA-1 cells. Expression of DR downstream pro-apoptotic proteins including caspase-3, 8, and Bax was concomitantly increased, but the phosphorylation of JAK2 and STAT3 and the expression of Bcl-2 were inhibited by treatment with bee venom and melittin in SKOV3 and PA-1 cells. Expression of cleaved caspase-3 was increased in SKOV3, but cleaved caspase-8 was increased in PA-1 cells. Moreover, deletion of DR3, DR4, and DR6 by small interfering RNA significantly reversed bee venom and melittin-induced cell growth inhibitory effect as well as down regulation of STAT3 by bee venom and melittin in SKOV3 and PA-1 ovarian cancer cell. These results suggest that bee venom and melittin induce apoptotic cell death in ovarian cancer cells through enhancement of DR3, DR4, and DR6 expression and inhibition of STAT3 pathway.