# Effect of _Allium sensecens_ Extract on Sorafenib Resistance in Hepatocarcinoma Cells
## 4 Discussion  
HCC, a primary liver cancer, is the second most fatal cancer type worldwide. Obesity is a major causative reason underlying HCC, wherein the modulation of obesity is important to reduce its incidence rate [19]. Notably, drug resistance occurs frequently and adversely affects the efficient HCC treatment. The attenuation of drug resistance is crucial for the effective treatment of HCC and finding a natural bioactive substance that can reduce drug resistance is indeed essential. Drug-resistant cells express high levels of PRELI, in addition to high cellular viability. In this study (Figure 1), we demonstrated the modeling of resistant cells. _Allium_ species are effective in the treatment of various diseases through their bioactive compounds, including sulfur compounds and polyphenols [20; 21]. Notably, _A. senescens_ is involved in suppressing cancer growth and development, it has anti-inflammatory and antioxidative activities, and contains bioactive compounds, such as allicin, allinin, antifungal activators [20; 22], and polyphenols (hydroxycinnamic acids such as ferulic acid, \(p\)-coumaric acid, and phytosterols) [20]. High-end chromatography revealed that the _A. senescens_ extract contained \(p\)-coumaric acid, with the exception of ferulic acid, luteolin, apigenin, and naringenin. As mentioned earlier, sorafenib enhances an increase in cellular ROS levels, and under the influence of sorafenib, polyphenols reinforce resistance to ROS to survive this stress. Unlike the resistant cells with upregulated PRELI levels, cells exposed to \(p\)-coumaric acid or the extract showed downregulated levels of PRELI. Notably, the extract strongly downregulated the expression of PRELI (Figure 3) in resistant cells. \(p\)-coumaric acid exhibits antioxidant, anti-proliferative, antibacterial, antiangiogenic, antimalogenic, antimutagenic, and antigenotoxic properties as well as mediates lipoprotein peroxidation [23]. Additionally, although \(p\)-coumaric acid has been shown to be cytotoxic to drug-resistant leukemia cell lines [24], the cytotoxic mechanism was not demonstrated in drug-resistant cells. These results indicated that \(p\)-coumaric acid attenuates drug resistance through the downregulation of PRELI in resistant cells, wherein bioactive compounds associated with MDR reversing activators, including alkaloids, curcumin, dihydropychantol A, guggulsterone, phenolic diterpenes, tetrandrine, and vincristine also induce such effects [25]. Contrary to the levels of the influx transporters, the expression of the efflux transporters was downregulated in the extract-exposed-resistant cells (Figures 4 and 5). In addition, at low levels of PRELI, the resistant cells showed upregulated levels of the influx transporters (Figures 4 and 5). S sorafenib is an important anticancer drug that affects HCC cells through OCT-1, and drug-resistant cells break down it to sorafenib glucuronide via cytochrome P450 [26]. The modified sorafenib, sorafenib glucuronide, is excreted by ABC transporters [27]. Resistant cells alter their genetic expression, including increases in ABCB1, ABCC2, and ABCG2, in contrast to OCT-1. In our previous report [11], we found that G3 LEA containing the PRELI motif was associated with resistance against vancomycin in bacteria, and that the suppression of PRELI is an effective modulation of efflux and influx transporters in HCC cells. Attenuation of PRELI caused by the _A. senescens_ extract and \(p\)-coumaric acid indicates that the two substances are effective in treating HCC without drug resistance. Furthermore, _A. senescens_ was synergized with _PRELI_ knockdown to regulate transporters in HCC cells. In particular, synergistic effects of the extract-exposed and _PRELI_-knocked down resistant cells are similar to those of the susceptible cells. In addition to ordinary pathways, sorafenib enhances the apoptosis of HCC cells by altering various pathways, including the 5' AMP-activated protein kinase (AMPK) pathway, microRNA regulation, sphingolipid metabolism, ER stress, and autophagy [28].