Florida A&M University
Breast Cancer predominantly affects women in the United States, and around 10-14 % of all breast cancers are triple negative type (TNBC), which are having limited effective therapeutic options readily available. Anti-cancer potential of cannabidiol (CBD) is well demonstrated in various cancers but poor solubility and increased metabolism by CYP enzymes limit the bioavailability of CBD. So, we hypothesize that therapeutic usage of human umbilical cord stem cell derived exosomes (hUCMSCs-EX) will serve as an ideal delivery platform not only for increasing the bioavailability and anticancer effects of CBD but also for overcoming resistance of docetaxel (DTX) and Doxorubicin (DOX) in MDA-MB-231 (i.e., CB1, CB2, and CD44 receptors expressing) cells.
Synthetic CBD (PurisysTM, GA; GMP grade) showed cytotoxic effects in both 2D and 3D cultures of MDA-MB-231, MDA-MB-468 and Doxorubicin (DOX) resistant MDA-MB-231 cells. RNA sequencing revealed alterations of various genes, among which GADD45A, GADD45G, Integrin alpha 5, integrin beta 5 were identified to be affected by CBD treatment in MDA-MB-231 cells. Flow cytometry of cell cycle analysis revealed that CBD induces G1 phase cell cycle arrest in MDA-MB-231 and MDA-MB-468 cells. CBD was found to be a potent sensitizer and increased the sensitization of Docetaxel (DTX) and DOX to MDA-MB-231 (by 8.2 and 2.5-fold respectively) and MDA-MB-468 (by 4.6 and 3-fold respectively) cells. Moreover, CBD (2.5 µM) pretreatment significantly improved the sensitivity of DOX in DOX resistant MDA-MB-231 cells response by 4-fold higher when compared to DOX alone.
We also developed stable formulation of CBD loaded exosomes (CBD-EX) by using sonoporation technique. CBD-EX significantly decreased the proliferation of TNBC cells. In addition, CBD-EX (2.5 µM; i.p. twice a week) in combination with DOX (2 mg/kg i.v. twice a week) significantly decreased the tumor burden in MDA-MB-231 xenografts in comparison to CBD and DOX combination alone. This suggests the role of CBD-EX in improving the sensitivity of DOX.
In summary, our results demonstrate that CBD shows not only anticancer activity against MDA-MB-231, MDA-MB-468 and DOX-resistant MDA-MB-231 cells but also acts as a potent chemosensitizer for conventional chemotherapeutics.
Co-authors: Mandip Sachdeva1, Nil Patel1, Nagavendra Kominneni1, David Meckes1, Li Sun1, Aragaw Gebeyhu1, Anil Kalvala1, Peggy Arthur1, Leanna Duke1
1Florida A&M University