Writing in the journal Carcinogenesis, Manjinder Kaur from the Department of Pharmaceutical Sciences, Skaggs School of Pharmacy and Pharmaceutical Studies, and colleagues said their molecular studies showed that bitter melon juice (BMJ) activates AMPK in the cells both in vitro and in vivo (using mouse models) and induced strong apoptotic (programmed cell) death.
The scientists bought Chinese variety of the melons from a local grocery store in the States, removed the pulp and seeds, then used a standard juicer and removed solids to make the juice.
Mouse tumor weight 64% lower
The juice was tested directly on cell cultures, but freeze dried and turned into powder form to feed mice. Tested against cancer cell cultures, bitter melon juice (diluted to 5% in water) reduced the viability of four pancreatic cancer cell lines tested.
Viability of AsPC-1and Capan-2 cancer cells fell by up to 92%, while BxPC-3 and MiaPaCa-2 viability fell by up to 98%, with BMJ efficacy varying according to 24h, 48h and 72h treatment periods.
In vivo tests with mice using freeze dried BMJ powder in 5mg doses daily for six weeks resulted in a 64% mean reduction in MisPaCa-2 tumor weight (the cancer cells were implanted in mice) against a control group, with no apparent adverse effects.
Summing up their research, the scientists wrote: “Considering the short survival and high mortality due to pancreatic cancer, BMJ that is widely consumed as vegetable and for health benefits could have significant translation relevance in managing this deadly malignancy.”
Kaur et al. described pancreatic cancer as an "aggressive malignancy" that develops in a relatively symptom-free manner and is usually at advanced stage at the time of diagnosis.
Chemotherapy is current frontline treatment
Chemotherapy was the frontline treatment for the disease, they added, but its remedial and survival benefits alone or in tandem with other therapies was below six months (median life), while only 3-5% of people survived a further five years.
As a commonly consumed vegetable in Asian and African countries, the scientists said there was growing interest in bitter melon for its beneficial effects against other illnesses such as diabetes, obesity and hyperlipidemia.
Besides these effects, Kaur et al. said previous studies (e.g. Nerurkar et al. 2010) had shown the efficacy of bitter melon extract and its bioactive compounds in terms of its anti-cancer properties, against leukemia, breast, prostrate and colon cancers.
Introducing their research, the team added: "However, there is no published report on bitter melon's efficacy against pancreatic cancer."
Possible mechanism of action...
Discussing their results, and possible mechanism of action for the observed effects in pancreatic cancer cells, the scientists said such cells usually generated more reactive oxygen species (ROS) than normal cells.
Thus, any increase in ROS or oxidative stress by pharmacological agents could push tumor cells "beyond the breaking point in terms of DNA damage, liquid peroxidation or protein oxidation, whereas normal cells...remain largely unaffected," they wrote.
"Therefore, it is quite possible that BMJ-induced apoptotic death could be through an increased oxidative stress in pancreatic cancer cells," Kaur et al. said.
But they insisted more studies were needed to understand the effect the juice had on ROS and cellular redox signalling, as well as their connection with apoptosis induction in pancreatic cancer cells.
Title: ‘Bitter melon juice activates cellular energy sensor AMP-activated protein kinase causing apoptotic death of human pancreatic carcinoma cells’
Authors: Kaur, M, Deep, G., Jain, A.K., Raina, K., Agarwal, C., Wempe, M.F., Agarwal, R.
Source: Carcinogenesis, published online ahead of print, March 8 2013, doi:10.1093/carcin/bgt081