July 30, 2018

Expert reaction to study looking at using cannabinoids alongside chemotherapy for pancreatic cancer in mice

Scientists publishing in Oncogene examine – using mice – whether a substance in cannabis plants might boost treatments for patients with pancreatic cancer.

Dr Chiara Braconi, Clinician Scientist at The Institute of Cancer Research, London, and Consultant Medical Oncologist at The Royal Marsden NHS Foundation Trust, said:

“Pancreatic cancer is one of the most hard-to-treat cancers, and new treatments are urgently needed. This study showed that by blocking a protein called GPR55, a cannabinoid drug seemed to slow the growth of pancreatic cancer cells. The researchers also found that the effects of chemotherapy and cannabinoids seemed to boost each other when used in combination.

“While the results look promising, there are still a number of important unknowns. We don’t know how cannabinoids will interact with other drugs, including chemotherapies, in people. The GPR55 protein is upregulated in around 30 per cent of pancreatic tumours, so it is likely that only a subset of people with pancreatic cancer would stand to benefit.

“This is early-stage research carried out in mice – clinical studies are needed before we can recommend the use of cannabinoids in routine practice.”

Prof Dorothy Bennett, Director of the Molecular and Clinical Sciences Research Institute, St George’s, University of London (SGUL), said:

“The authors do present data that mean and median survival times of genetically engineered mice with pancreatic cancer were almost tripled after treatment with the non-psychoactive cannabinoid CBD (found in cannabis) in combination with the standard chemotherapy drug gemcitabine, compared with gemcitabine alone.

“Caution is needed because this is a mouse study (mice can have different drug responses from humans), and the groups were small (7 versus 8 mice).  So this can be seen as preliminary evidence for lifespan extension, and more confirmation would be desirable, perhaps in other models of pancreatic cancer.

“Nonetheless these data are interesting and are supported by studies indicating inhibition of pancreatic cancer cell growth in cell cultures by CBD, and by evidence that genetically engineered mice susceptible to pancreatic cancer also had prolonged survival following the cancer, if they were additionally engineered to lack a receptor protein (GPR55) that enables cells to respond to CBD.”

* ‘GPR55 signalling promotes proliferation of pancreatic cancer cells and tumour growth in mice, and its inhibition increases effects of gemcitabine’ by R. Ferro et al. published in Oncogene on Monday 30th July.

Declared interests

Dr Chiara Braconi: “No conflict of interest.”

Prof Dorothy Bennett: “No conflict of interest.”