Cannabis Extract PHEC-66 Triggers Cell Death in Melanoma Cells in Laboratory Study
A cannabis-derived extract called PHEC-66 slowed the growth of cultured human melanoma cells and activated molecular signals associated with programmed cell death, according to a 2024 study published in the journal Cells.
The findings offer a possible starting point for future drug development, but they do not show that cannabis extracts can treat melanoma in people. The research was conducted in laboratory-grown cell lines, and additional preclinical studies would be needed before any clinical testing.
Melanoma develops from pigment-producing skin cells called melanocytes. Although it is less common than basal cell or squamous cell skin cancer, melanoma is more likely to invade nearby tissue and spread to other parts of the body. Current treatment can include surgery, immunotherapy, targeted therapy, radiation, or chemotherapy, depending on the stage and characteristics of the disease. The National Cancer Institute provides an overview of standard melanoma treatment options.
What the study found
Researchers from Australian institutions examined PHEC-66 in three human melanoma cell lines: two derived from primary tumors and one from metastatic melanoma. Their experiments evaluated cell viability, cannabinoid-receptor signaling, reactive oxygen species, apoptosis, and cell-cycle activity.
PHEC-66 reduced melanoma-cell viability and appeared to affect the cannabinoid receptors CB1 and CB2. Blocking those receptors partly weakened the extract’s effects in some of the cell lines, suggesting that the receptors may contribute to the response. However, the results varied between cell lines, indicating that the extract does not act identically in every melanoma model.
The researchers also observed several changes consistent with apoptosis, a form of controlled cell death. Treatment was associated with increased expression of the pro-apoptotic BAX gene and reduced expression of the anti-apoptotic Bcl-2 gene. The cells also showed increased levels of reactive oxygen species, DNA fragmentation, and disruption of normal cell-cycle progression at the G1 checkpoint.
Together, these changes may help explain how PHEC-66 inhibited growth in the cultured melanoma cells. The study’s conclusions, however, describe a possible mechanism rather than proof that the extract would work as a cancer medicine.
Earlier work and important limitations
The same research group reported in a 2023 Cells study that PHEC-66 reduced the viability of several melanoma cell lines in laboratory experiments. The extract had a lesser effect on cultured keratinocytes, melanocytes, and dermal fibroblasts at some of the tested concentrations. Those findings may indicate a degree of selectivity, but results from cell cultures do not reliably predict safety or effectiveness in the human body.
The studies did not establish an effective dose for patients, determine how the extract would be delivered, or test whether it can shrink tumors in animals or people. They also do not establish that PHEC-66 would improve the effects of existing melanoma treatments. The researchers identified combination therapy and more sophisticated preclinical models as areas for future investigation.
Patients should not substitute cannabis products for proven melanoma treatment. The National Cancer Institute notes that the U.S. Food and Drug Administration has not approved cannabis or cannabinoids as a treatment for cancer. Some cannabinoid medicines are approved for particular chemotherapy-related symptoms, such as nausea and vomiting, but that is different from treating the cancer itself. The NCI’s evidence summary on cannabis and cannabinoids explains the distinction.
PHEC-66 therefore remains an experimental research compound. Its effects on melanoma cells make it worthy of further study, but clinical trials will be necessary to determine whether the extract is safe, how it interacts with other therapies, and whether it provides any meaningful benefit to people with melanoma.
