In vitro 3D evaluation of penetrability of SRJ09, a semisynthetic anticancer agent (1048.4)

Abstract

The inability of anticancer drugs to penetrate through the tumor within their respective pharmacokinetic lifespan to destroy all the tumor cells is recognized as one of the factors that lead to poor outcome of chemotherapy. SRJ09 (3,19‐(2‐bromobenzylidene)andrographolide) has been identified as a lead anticancer agent on the basis of its selectivity towards breast and colon cancer cell line panels (Jada et al (2008) Br J Pharmacol, 155(5):641‐54). In our recent landmark study (Hocker et al (2013), PNAS, 110(25):10201‐6), we showed that the compound disrupts mutant K‐Ras activity by binding to it. In this present investigation, the penetrability of SRJ09 through the DLD‐1 colon cancer multi cell layer (MCL) was evaluated. DLD‐1 MCL is established by culturing the cells in collagen‐coated plastic insert. The amount of SRJ09 that penetrated through MCL was quantitated by utilizing high performance liquid chromatography (HPLC). Histopathological staining was used to visualize the morphology of MCL. Chemosensitivity assay was performed to assess the anticancer activity of SRJ09 in DLD‐1 cells. SRJ09 was able to penetrate through 3D tumor and is inversely proportional with the MCL thickness. Furthermore, the compound has better penetrability compared with doxorubicin, a clinical anticancer drug. Subsequent histopathological analysis revealed that the integrity of the MCL was retained and no visible damage was inflicted on the cell membrane, confirming the penetration of SRJ09 is by diffusion. Chemosensitivity assay demonstrated that SRJ09 was able to achieve IC50 value of 40.7 µM upon 1 hour exposure time on DLD‐1 cells which was approximately 4 folds lower than andrographolide, the parent compound of SRJ09. In conclusion, SRJ09 successfully penetrated through DLD‐1 MCL by diffusion and could be potentially developed as a clinically relevant anti‐colon cancer drug. This study was funded by Universiti Putra Malaysia Research University Grant Scheme (04‐01‐09‐0713RU; 04‐02‐12‐2017RU).