MOF enhances the sensitivity and selectivity of sorafenib as an anticancer drug against hepatocellular carcinoma and colorectal cancer in vitro

Abstract

Hepatocellular carcinoma (HCC) is the fifth most common cancer in the world and the second largest contributor to cancer mortality. Sorafenib (SOR) is a drug approved by the Food and Drug Administration (FDA) to treat liver cancer, but it has harsh side effects on normal cells, is expensive, and is associated with chemoresistance through frequent use. This work aims to test the hypothesis that loading sorafenib onto a metal-organic framework (MOF) as a nanocarrier can help increase the potency and selectivity of sorafenib on hepatocellular carcinoma (HCC) and explore its potential application in colorectal cancer treatment. MOFs were prepared and chemically characterized using XRD, FTIR, and BET. The crystallite size was calculated using the Scherrer equation, and comprehensive FTIR peak assignments were performed to elucidate drug-MOF interactions. Sorafenib was loaded onto the MOF, entrapment efficiency (EE) as well as loading capacity (LC) were calculated using the formulas: EE% = (sorafenib content loaded in MIL-53(Fe)) / (initial sorafenib content) × 100% and LC% = (sorafenib content loaded in MIL-53(Fe)) / (sorafenib loaded + weight of MIL-53(Fe)) × 100%, and in vitro release was evaluated under sink conditions in phosphate-buffered saline (PBS, pH 7.4). The cytotoxic effect of sorafenib on normal HFb-4, HepG2, and HCT-116 cells was measured before and after loading onto MOF, and the selectivity index (SI) was calculated using the formula: SI = IC50 (normal cells) / IC50 (cancer cells). Apoptosis and cell cycle analysis were also performed using flow cytometry. The present study showed entrapment efficiency (EE) = 88.97% and loading capacity (LC) = 23.5% of sorafenib. The high variability in LC indicates batch-to-batch reproducibility challenges that require optimization. Spontaneous release of the loaded drug was encountered within 48 h. XRD analysis showed crystallite sizes calculated using the Scherrer equation, confirming successful drug encapsulation with reduced crystallinity of sorafenib within the MOF structure. Before loading, the MTT test showed IC50 for sorafenib = 5.88, 12.5, 29.4 µg/ml on HFb-4, HepG2, and HCT-116 cells, respectively. After loading, IC50 values of 3.3, 5.5, and 7.9 µg/ml were found considering the loading capacity. The selectivity index (SI) values showed modest improvements: 0.46 to 0.6 for HepG2 and 0.2 to 0.42 for HCT-116. While these improvements are statistically significant, the SI values remain below the ideal threshold of > 2, indicating that further optimization is needed to achieve clinically relevant selectivity. There was a direct correlation between the cytotoxic effect and the degree of apoptosis in the HepG2 cell line. The present study has also proved cell cycle arrest at the G0/G1 phase after treatment with sorafenib loaded onto the MOF (SOR-MIL-53). We conclude from the current study that MOF as a carrier is considered a promising nanocarrier for enhancing drug potency as an anti-cancer agent, though selectivity improvements remain modest. Loading Sorafenib on MOF showed enhanced potency on HepG2 cell lines and demonstrated potential for colorectal cancer applications, despite sorafenib not being FDA-approved for this indication.