GBM is a highly malignant tumor of the central nervous system that seriously threatens human life and health. At present, there are fewer clinical treatment options available for GBM. With the development of GBM, problems such as drug resistance and poor prognosis have severely hindered TMZ treatment. halo has been used by the FDA to treat intensive malaria for many years. In recent years, it has been found that a halo can not only treat malaria but also has good anti-GBM activity, and it has the potential to become a drug for GBM. In this study, we confirmed that the halo has a good inhibitory effect on GBM cells, and with increasing concentration, this inhibitory effect becomes increasingly obvious. In addition, the halo can not only play a beneficial role in suppressing GBM cells at a certain concentration but also has no cytotoxic effect on normal cells. We believe that the halo has good antitumor activity and safety within a certain range. halo, a classic antimalarial drug, has been shown to be effective in treating GBM and provides a new therapeutic option for GBM in the clinic. Since GBM is a brain tumor with a very high degree of malignancy, the treatment difficulty of GBM is greatly enhanced due to the blocking effect of blood-brain barrier on foreign substances, which leads to the difficulty of the treatment of many drugs to meet clinical expectations. Although the antitumor activity of halo on GBM has been preliminarily confirmed in this study, the blood-brain barrier permeability of halo needs to be further discussed if it is further applied to the clinic. So far, no studies have explicitly reported whether halo can cross the blood-brain barrier, but this study evaluated the data obtained by using the tool for evaluating chemical ADMET properties (admetSAR) in the Drug Bank database and found [33] that the drug affinity properties of halo showed that, The halo blood-brain barrier penetration rate was 94.9%. This result suggests that halo can penetrate the blood-brain barrier, but no studies have been conducted to further verify this. To this end, further studies will be conducted to verify the permeability of halo's blood-brain barrier.
Anti-tumor drugs usually have high anti-tumor pharmacological activity, but also may have some low safety problems. A previous report found that halo may cause cardiotoxicity, but a 2009 survey of global data showed that the drug is safe when taken correctly[34], so it should not be given to patients with heart conduction defects, nor should it be combined with mefloquine. In addition, studies have suggested that cardiotoxicity will not occur when the dose of halo is below 24 mg/kg in vivo [35]. The concentration of drugs in vivo used in this study was 15mg/kg, which was far less than the recommended concentration. Moreover, HE staining of nude mouse hearts also showed that there was no substantial damage to the heart, and it also had certain safety for liver and kidney. In addition, in this study, it was also found that halo had no effect on normal microglia at effective concentrations. Therefore, this study preliminarily discussed the anti-tumor activity and safety of halo in vivo and in vitro, and preliminarily proved that halo has not only anti-tumor activity but also certain safety. Considering some safety problems of halo in the clinical treatment of malaria, we believe that it is necessary to further explore the safety of halo in the treatment of GBM.
In recent years, autophagy has received a lot of attention in tumor treatment response. Autophagy is an environment dependent process, and there are many types of autophagy, different types of autophagy will produce different physiological processes. In the process of tumor occurrence and development, protective autophagy is conducive to promoting tumor growth, while toxic autophagy is conducive to inhibiting tumor growth. In recent years, a new autophagy regulatory gene, ATP6V0D2, has been widely studied. It is widely distributed in the cell membrane and cell membrane of multiple cell types and regulates a variety of physiological effects. ATP6V0D2 can inhibit inflammation and bacterial infection by promoting the fusion of self-feeding enzymes[23]. In addition, ATP6V0D2 can also mediate HIF-2α degradation, restricting macrophagocyte activity[36]. Autophagy guided by the V-ATP family of enzymes in which ATP6V0D2 is located is conducive to inhibiting the growth of tumors. It is expected to become a new target gene for tumor treatment as a key regulatory factor that promotes tumor autophagy[37–40]. Current studies have shown that ATP6V0D2 gene regulates tumor autophagy pathway and exerts anti-tumor effects only in a small number of tumor studies, such as human gastric cancer and liver cancer.[41–43]. In this study, we evaluated the expression of the ATP6V0D2 gene in GBM patients through the GEO database. We found that ATP6V0D2 gene expression is low in tumor patients. In addition, we combined clinical samples and found that low expression of the ATP6V0D2 gene in tumor patients is conducive to the occurrence and development of GBM. We initially determined that the ATP6V0D2 gene is a key gene that regulates GBM. In addition, in this study, we found that a halo significantly increased the abundance of the ATP6V0D2 gene, and as the concentration increased, the effect of this increase became more obvious. The ATP6V0D2 gene is an autophagy regulatory gene, and its upregulation and downregulation are mediated by autophagy. Our research also revealed that the halo increased ATP6V0D2 gene expression while also promoting the expression of autophagy-related proteins in GBM cells and triggering autophagy in GBM cells. This confirmed that the halo can increase ATP6V0D2 to promote spontaneous toxicity in GBM cells. Our research showed that the halo can promote the toxic autophagy of GBM cells to suppress their proliferation, migration, and invasion, and ATP6V0D2 is key to regulating this process. This discovery not only compensates for the lack of halo research on anti-GBM activity mechanisms but also revealed a new key anti-GBM cancer suppressor gene, ATP6V0D2. Low expression of the ATP6V0D2 gene in GBM is conducive to tumor development, and upregulation of the ATP6V0D2 gene is conducive to promoting GBM-induced autophagy, thereby playing a role in preventing GBM. We have demonstrated that ATP6V0D2 gene is a key regulatory gene of GBM, but the regulatory role of ATP6V0D2 gene in other tumors has not been reported. We considered that ATP6V0D2 gene has a good regulatory role in GBM and may also have similar regulatory roles in other tumors, which is worthy of further exploration.
Overall, we prove that in addition to being an antimalarial agent, a halo is also a drug with good anti-GBM effects. It has the potential to be used as an anti-GBM agent and can provide new options for patients with clinically resistant GBM. In addition, we confirmed that the halo can act on the anti-GBM cell line U251 by facilitating the autophagy pathway in tumors, which will provide new research for clinical GBM treatment. Moreover, our research revealed that the ATP6V0D2 gene is a key gene for the halo that regulates GBM cell autophagy, and low ATP6V0D2 gene expression in patients with GBM is closely related to tumor development. As a cancer suppressor gene, the ATP6V0D2 gene may be used for GBM treatment. This study provides new targets.