Pine (Pinus morrisonicola Hayata) needle extracts sensitize GBM8901 human glioblastoma cells to temozolomide by downregulating autophagy and O(6)-methylguanine-DNA methyltransferase expression

Natural products for combating multidrug resistance in cancer

Cancer cells frequently develop resistance to chemotherapeutic therapies and targeted drugs, which has been a significant challenge in cancer management. With the growing advances in technologies in isolation and identification of natural products, the potential of natural products in combating cancer multidrug resistance has received substantial attention. Importantly, natural products can impact multiple targets, which can be valuable in overcoming drug resistance from different perspectives. In the current review, we will describe the well-established mechanisms underlying multidrug resistance, and introduce natural products that could target these multidrug resistant mechanisms. Specifically, we will discuss natural compounds such as curcumin, resveratrol, baicalein, chrysin and more, and their potential roles in combating multidrug resistance. This review article aims to provide a systematic summary of recent advances of natural products in combating cancer drug resistance, and will provide rationales for novel drug discovery.

Autophagy machinery in glioblastoma: The prospect of cell death crosstalk and drug resistance with bioinformatics analysis

Brain tumors are common malignancies with high mortality and morbidity in which glioblastoma (GB) is a grade IV astrocytoma with heterogeneous nature. The conventional therapeutics for the GB mainly include surgery and chemotherapy, however their efficacy has been compromised due to the aggressiveness of tumor cells. The dysregulation of cell death mechanisms, especially autophagy has been reported as a factor causing difficulties in cancer therapy. As a mechanism contributing to cell homeostasis, the autophagy process is hijacked by tumor cells for the purpose of aggravating cancer progression and drug resistance. The autophagy function is context-dependent and its role can be lethal or protective in cancer. The aim of the current paper is to highlight the role of autophagy in the regulation of GB progression. The cytotoxic function of autophagy can promote apoptosis and ferroptosis in GB cells and vice versa. Autophagy dysregulation can cause drug resistance and radioresistance in GB. Moreover, stemness can be regulated by autophagy and overall growth as well as metastasis are affected by autophagy. The various interventions including administration of synthetic/natural products and nanoplatforms can target autophagy. Therefore, autophagy can act as a promising target in GB therapy.

Principle active metabolites of Pinus morrisonicola Hayata synergistically inhibit cell proliferation and autophagy to elevate apoptosis in hepatocellular carcinoma cells

Hepatocellular carcinoma (HCC), a common primary tumor of liver is a leading cause of cancer-associated deaths. Improving cellular apoptosis and enhancing autophagic clearance is been considered to improve treatment outcomes of HCC. Polyphenols from Pinus morrisonicola (Hayata) have shown various physiological and therapeutic benefits and the flavonoid chrysin is been known for their anticancer effects. However, the main bioactive principle and the mechanism underlying the antitumor activity of pine needle extract are not clear yet. In this study, the effects of ethanol extract from pine needle on HCC cells were determined. The results show that when compared with administration of chrysin alone, a fraction containing pinocembrin, chrysin, and tiliroside significantly reduced autophagy and increased apoptosis. The results also correlated with decrease in cell cycle regulators and the autophagic proteins like LC3-II. Collectively, the results imply the fraction containing pinocembrin, chrysin, and tiliroside as an ideal complementary medicine for an effective antitumor activity.

Anti-Aging Constituents from Pinus morrisonicola Leaves

Pinus morrisonicola Hayata is a unique plant species found in Taiwan. Previous studies have identified its anti-hypertensive, anti-oxidative, and anti-inflammatory effects. In this study, a bioactivity-guided approach was employed to extract 20 compounds from the ethyl acetate fraction of the ethanol extract of Pinus morrisonicola Hayata's pine needles. The anti-aging effects of these compounds were investigated using HT-1080 cells. The structures of the purified compounds were confirmed through NMR and LC-MS analysis, revealing the presence of nine flavonoids, two lignans, one coumarin, one benzofuran, one phenylic acid, and six diterpenoids. Among them, PML18, PML19, and PML20 were identified as novel diterpene. Compounds 3, 4, and 5 exhibited remarkable inhibitory effects against MMP-2 and showed no significant cell toxicity at 25 μM. Although the purified compounds showed lower activity against Pro MMP-2 and Pro MMP-9 compared to the ethyl acetate fraction, we speculate that this is the result of synergistic effects.

Anticancer Mechanism of Flavonoids on High-Grade Adult-Type Diffuse Gliomas

High-grade adult-type diffuse gliomas are the most common and deadliest malignant adult tumors of the central nervous system. Despite the advancements in the multimodality treatment of high-grade adult-type diffuse gliomas, the five-year survival rates still remain poor. The biggest challenge in treating high-grade adult-type diffuse gliomas is the intra-tumor heterogeneity feature of the glioma tumors. Introducing dietary flavonoids to the current high-grade adult-type diffuse glioma treatment strategies is crucial to overcome this challenge, as flavonoids can target several molecular targets. This review discusses the anticancer mechanism of flavonoids (quercetin, rutin, chrysin, apigenin, naringenin, silibinin, EGCG, genistein, biochanin A and C3G) through targeting molecules associated with high-grade adult-type diffuse glioma cell proliferation, apoptosis, oxidative stress, cell cycle arrest, migration, invasion, autophagy and DNA repair. In addition, the common molecules targeted by the flavonoids such as Bax, Bcl-2, MMP-2, MMP-9, caspase-8, caspase-3, p53, p38, Erk, JNK, p38, beclin-1 and LC3B were also discussed. Moreover, the clinical relevance of flavonoid molecular targets in high-grade adult-type diffuse gliomas is discussed with comparison to small molecules inhibitors: ralimetinib, AMG232, marimastat, hydroxychloroquine and chloroquine. Despite the positive pre-clinical results, further investigations in clinical studies are warranted to substantiate the efficacy and safety of the use of flavonoids on high-grade adult-type diffuse glioma patients.

Biochanin A Sensitizes Glioblastoma to Temozolomide by Inhibiting Autophagy

Resistance to temozolomide (TMZ) chemotherapy is the main reason for treatment failure in patients with glioblastoma (GBM). In the present study, we investigated biochanin A (BCA) a potent sensitizer of TMZ in GBM. We observed that BCA significantly enhanced cell sensitivity to TMZ in vitro and in vivo. Mechanistically, the specific chemosensitizing effect of BCA is mediated by autophagy inhibition. Moreover, by performing a molecular docking analysis, we demonstrated that BCA interacts with AMPK residues and impairs autophagy by regulating the AMPK/ULK1 pathway. These results suggest that BCA is a potential therapeutic agent that sensitizes GBM to TMZ and provide new insight into its therapeutic potential in chemoresistant GBM.

Flavonoids Synergistically Enhance the Anti-Glioblastoma Effects of Chemotherapeutic Drugs

Flavonoids are polyphenolic plant secondary metabolites with pleiotropic biological properties, including anti-cancer activities. These natural compounds have potential utility in glioblastoma (GBM), a malignant central nervous system tumor derived from astrocytes. Conventional GBM treatment modalities such as chemotherapy, radiation therapy, and surgical tumor resection are beneficial but limited by extensive tumor invasion and drug/radiation resistance. Therefore, dietary flavonoids—with demonstrated anti-GBM properties in preclinical research—are potential alternative therapies. This review explores the synergistic enhancement of the anti-GBM effects of conventional chemotherapeutic drugs by flavonoids. Primary studies published between 2011 and 2021 on flavonoid–chemotherapeutic synergy in GBM were obtained from PubMed. These studies demonstrate that flavonoids such as chrysin, epigallocatechin-3-gallate (EGCG), formononetin, hispidulin, icariin, quercetin, rutin, and silibinin synergistically enhance the effects of canonical chemotherapeutics. These beneficial effects are mediated by the modulation of intracellular signaling mechanisms related to apoptosis, proliferation, autophagy, motility, and chemoresistance. In this light, flavonoids hold promise in improving current therapeutic strategies and ultimately overcoming GBM drug resistance. However, despite positive preclinical results, further investigations are necessary before the commencement of clinical trials. Key considerations include the bioavailability, blood–brain barrier (BBB) permeability, and safety of flavonoids; optimal dosages of flavonoids and chemotherapeutics; drug delivery platforms; and the potential for adverse interactions.

Neuroprotective Potential of Chrysin: Mechanistic Insights and Therapeutic Potential for Neurological Disorders

Chrysin, a herbal bioactive molecule, exerts a plethora of pharmacological effects, including anti-oxidant, anti-inflammatory, neuroprotective, and anti-cancer. A growing body of evidence has highlighted the emerging role of chrysin in a variety of neurological disorders, including Alzheimer’s and Parkinson’s disease, epilepsy, multiple sclerosis, ischemic stroke, traumatic brain injury, and brain tumors. Based on the results of recent pre-clinical studies and evidence from studies in humans, this review is focused on the molecular mechanisms underlying the neuroprotective effects of chrysin in different neurological diseases. In addition, the potential challenges, and opportunities of chrysin’s inclusion in the neurotherapeutics repertoire are critically discussed.

Natural bioactive molecules: An alternative approach to the treatment and control of glioblastoma multiforme

Glioblastoma multiforme is one of the most deadly malignant tumors, with more than 10,000 cases recorded annually in the United States. Various clinical analyses and studies show that certain chronic diseases, including cancer, interact between cell-reactive radicals rise and pathogenesis. Reactive oxygen and nitrogenous sources include endogenous (physiological processes), and exogenous sources contain reactive oxygen and nitrogen (xenobiotic interaction). The cellular oxidation/reduction shifts to oxidative stress when the regulation mechanisms of antioxidants are surpassed, and this raises the ability to damage cellular lipids, proteins, and nucleic acids. OBJECTIVE: This review is focused on how phytochemicals play crucial role against glioblastoma multiforme and to combat these, bioactive molecules and their derivatives are either used alone, in combination with anticancer drugs or as nanomedicine formulations for better cancer theranostics over the conventional approach. CONCLUSION: Bioactive molecules found in seeds, vegetables, and fruits have antioxidant, anti-inflammatory, and anticancer properties that may help cancer survivors feel better throughout chemotherapy or treatment. However, incorporating them into the nanocarrier-based drug delivery for the treatment of GBMs, which could be a promising therapeutic strategy for this tumor entity, increasing targeting effectiveness, increasing bioavailability, and reducing side effects with this target-specificity, drug internalization into cells is significantly improved, and off-target organ aggregation is reduced.

Current Perspective on the Natural Compounds and Drug Delivery Techniques in Glioblastoma Multiforme

Simple Summary

Glioblastoma multiforme (GBM) is one of the belligerent neoplasia that metastasize to other brain regions and invade nearby healthy tissues. However, the treatments available are associated with some limitations, such as high variations in solid tumors and deregulation of multiple cellular pathways. The heterogeneity of the GBM tumor and its aggressive infiltration into the nearby tissues makes it difficult to treat. Hence, the development of multimodality therapy that can be more effective, novel, with fewer side effects, improving the prognosis for GBM is highly desired. This review evaluated the use of natural phytoconstituents as an alternative for the development of a new therapeutic strategy. The key aspects of GBM and the potential of drug delivery techniques were also assessed, for tumor site delivery with limited side-effects. These efforts will help to provide better therapeutic options to combat GBM in future.

Abstract

Glioblastoma multiforme (GBM) is one of the debilitating brain tumors, being associated with extremely poor prognosis and short median patient survival. GBM is associated with complex pathogenesis with alterations in various cellular signaling events, that participate in cell proliferation and survival. The impairment in cellular redox pathways leads to tumorigenesis. The current standard pharmacological regimen available for glioblastomas, such as radiotherapy and surgical resection following treatment with chemotherapeutic drug temozolomide, remains fatal, due to drug resistance, metastasis and tumor recurrence. Thus, the demand for an effective therapeutic strategy for GBM remains elusive. Hopefully, novel products from natural compounds are suggested as possible solutions. They protect glial cells by reducing oxidative stress and neuroinflammation, inhibiting proliferation, inducing apoptosis, inhibiting pro-oncogene events and intensifying the potent anti-tumor therapies. Targeting aberrant cellular pathways in the amelioration of GBM could promote the development of new therapeutic options that improve patient quality of life and extend survival. Consequently, our review emphasizes several natural compounds in GBM treatment. We also assessed the potential of drug delivery techniques such as nanoparticles, Gliadel wafers and drug delivery using cellular carriers which could lead to a novel path for the obliteration of GBM.

Natural Compounds in Glioblastoma Therapy: Preclinical Insights, Mechanistic Pathways, and Outlook

Simple Summary

Glioblastoma (GBM) is a tumor of the brain or spinal cord with poor clinical prognosis. Current interventions, such as chemotherapy and surgical tumor resection, are constrained by tumor invasion and cancer drug resistance. Dietary natural substances are therefore evaluated for their potential as agents in GBM treatment. Various substances found in fruits, vegetables, and other natural products restrict tumor growth and induce GBM cell death. These preclinical effects are promising but remain constrained by natural substances’ varying pharmacological properties. While many of the reviewed substances are available as over-the-counter supplements, their anti-GBM efficacy should be corroborated by clinical trials moving forward.

Abstract

Glioblastoma (GBM) is an aggressive, often fatal astrocyte-derived tumor of the central nervous system. Conventional medical and surgical interventions have greatly improved survival rates; however, tumor heterogeneity, invasiveness, and chemotherapeutic resistance continue to pose clinical challenges. As such, dietary natural substances—an integral component of the lifestyle medicine approach to chronic diseases—are examined as potential chemotherapeutic agents. These heterogenous substances exert anti-GBM effects by upregulating apoptosis and autophagy, inducing cell cycle arrest, interfering with tumor metabolism, and inhibiting proliferation, neuroinflammation, chemoresistance, angiogenesis, and metastasis. Although these beneficial effects are promising, natural substances’ efficacy in GBM is constrained by their bioavailability and blood–brain barrier permeability; various chemical formulations are proposed to improve their pharmacological properties. Many of the reviewed substances are available as over-the-counter dietary supplements, underscoring their viability as lifestyle interventions. However, clinical trials remain necessary to substantiate the in vitro and in vivo properties of natural substances.

Autophagy: Mechanisms and Therapeutic Potential of Flavonoids in Cancer

Autophagy, which is a conserved biological process and essential mechanism in maintaining homeostasis and metabolic balance, enables cells to degrade cytoplasmic constituents through lysosomes, recycle nutrients, and survive during starvation. Autophagy exerts an anticarcinogenic role in normal cells and inhibits the malignant transformation of cells. On the other hand, aberrations in autophagy are involved in gene derangements, cell metabolism, the process of tumor immune surveillance, invasion and metastasis, and tumor drug-resistance. Therefore, autophagy-targeted drugs may function as anti-tumor agents. Accumulating evidence suggests that flavonoids have anticarcinogenic properties, including those relating to cellular proliferation inhibition, the induction of apoptosis, autophagy, necrosis, cell cycle arrest, senescence, the impairment of cell migration, invasion, tumor angiogenesis, and the reduction of multidrug resistance in tumor cells. Flavonoids, which are a group of natural polyphenolic compounds characterized by multiple targets that participate in multiple pathways, have been widely studied in different models for autophagy modulation. However, flavonoid-induced autophagy commonly interacts with other mechanisms, comprehensively influencing the anticancer effect. Accordingly, targeted autophagy may become the core mechanism of flavonoids in the treatment of tumors. This paper reviews the flavonoid-induced autophagy of tumor cells and their interaction with other mechanisms, so as to provide a comprehensive and in-depth account on how flavonoids exert tumor-suppressive effects through autophagy.

Anti-neoplastic Potential of Flavonoids and Polysaccharide Phytochemicals in Glioblastoma

Clinically, gliomas are classified into four grades, with grade IV glioblastoma multiforme being the most malignant and deadly, which accounts for 50% of all gliomas. Characteristically, glioblastoma involves the aggressive proliferation of cells and invasion of normal brain tissue, outcomes as poor patient prognosis. With the current standard therapy of glioblastoma; surgical resection and radiotherapy followed by adjuvant chemotherapy with temozolomide, it remains fatal, because of the development of drug resistance, tumor recurrence, and metastasis. Therefore, the need for the effective therapeutic option for glioblastoma remains elusive. Previous studies have demonstrated the chemopreventive role of naturally occurring pharmacological agents through preventing or reversing the initiation phase of carcinogenesis or arresting the cancer progression phase. In this review, we discuss the role of natural phytochemicals in the amelioration of glioblastoma, with the aim to improve therapeutic outcomes, and minimize the adverse side effects to improve patient's prognosis and enhancing their quality of life.

The effect of medicinal plants on multiple drug resistance through autophagy: A review of in vitro studies

Multiple drug resistance (MDR) often occurs after prolonged chemotherapy, leading to refractory tumor and cancer recurrence. Autophagy as a primarily process during starvation or stress has a bipolar nature in cancer. It can cause MDR to become more difficult or make resistant cancer cells more susceptible to chemotherapeutic agents. A number of natural products have been introduced to drug discovery for many years. Some of these compounds have been shown to reverse drug resistance by different regulatory mechanisms. In this review, the focus is on the role of medicinal plants in the MDR phenomenon, primarily through the autophagy process.

Targeting off-target effects: endoplasmic reticulum stress and autophagy as effective strategies to enhance temozolomide treatment

Glioblastoma multiforme (GBM) is the most common and aggressive adult primary central nervous system tumor. Unfortunately, GBM is resistant to the classic chemotherapy drug, temozolomide (TMZ). As well as its classic DNA-targeting effects, the off-target effects of TMZ can have pro-survival or pro-death roles and regulate GBM chemoradiation sensitivity. Endoplasmic reticulum (ER) stress is one of the most common off-target effects. ER stress and its downstream induction of autophagy, apoptosis, and other events have important roles in regulating TMZ sensitivity. Autophagy is an evolutionarily conserved cellular homeostasis mechanism that is closely associated with ER stress-induced apoptosis. Under ER stress, autophagy cannot only remove misfolded/unfolded proteins and damaged organelles and degrade and inhibit apoptosis-related caspase activation to reduce cell damage, but may also promote apoptosis dependent on ER stress intensity. Although some protein interactions between autophagy and apoptosis and common upstream signaling pathways have been found, the underlying regulatory mechanisms are still not fully understood. This review summarizes the possible mechanisms underlying the current known off-target roles of ER stress and downstream autophagy in the regulation of cell fate and evaluates their role in TMZ treatment and their potential as therapeutic targets.

A Review on the Dietary Flavonoid Tiliroside

Among flavonoid derivatives, tiliroside is a flavonoid contained in several edible plants or specific plant parts (fruits, leaves, or roots). These parts are often widely used as both food and medicines, in the treatment of various ailments and, in some cases, as food supplements. Considering the easy access to many publications concerning tiliroside and the lack of a review that summarizes the current progress in studies on its safety, efficacy, and presence in the plant kingdom, we present here a review paper on tiliroside and its principal derivatives. The paper also highlights the basic knowledge regarding this molecule, its derivatives, and the analytical approaches used for extraction and quantification, as well as reports on the biological activities against different key enzymes linked to various human diseases. The reported information is also devoted to highlighting the concept "learn from nature to discover new products," particularly in the development of new drugs, food supplements, and nutraceuticals, starting from a natural lead compound such as tiliroside and improving its biological activities (and selectivities) against a specific target for therapeutic purposes.

Chrysin Attenuates Cell Viability of Human Colorectal Cancer Cells through Autophagy Induction Unlike 5-Fluorouracil/Oxaliplatin

Chemotherapeutic 5-fluorouracil (5-FU) combined with oxaliplatin is often used as the standard treatment for colorectal cancer (CRC). The disturbing side effects and drug resistance commonly observed in chemotherapy motivate us to develop alternative optimal therapeutic options for CRC treatment. Chrysin, a natural and biologically active flavonoid abundant in propolis, is reported to have antitumor effects on a few CRCs. However, whether and how chrysin achieves similar effectiveness to the 5-FU combination is not clear. In this study, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), western blotting, fluorescence microscopy, and reactive oxygen species (ROS) production were assayed. We found that chrysin exhibited similar inhibition of cell viability as the 5-FU combination in a panel of human CRC cells. Furthermore, the results showed that chrysin significantly increased the levels of LC3-II, an autophagy-related marker, in CRC cells, which was not observed with the 5-FU combination. More importantly, blockage of autophagy induction restored chrysin-attenuated CRC cell viability. Further mechanistic analysis revealed that chrysin, not the 5-FU combination, induced ROS generation, and in turn, inhibited the phosphorylation of protein kinase B (Akt) and mammalian target of rapamycin (mTOR). Collectively, these results imply that chrysin may be a potential replacement for the 5-FU and oxaliplatin combination to achieve antitumor activity through autophagy for CRC treatment in the future.

Pine needle oil induces G2/M arrest of HepG2 cells by activating the ATM pathway

Over the last two decades, inducing DNA damage of cancer cells by natural medicines has become a research hotspot in the field of cancer treatment. Although various natural medicines have anticancer effects, very few studies have been conducted to explore the anti-cancer effect of pine needle oil. In the present study, the role of pine needle oil in inducing G2/M arrest in HepG2 cells was investigated. The data revealed that pine needle oil could induce DNA damage in a dose-dependent manner. In the pine needle oil-treated HepG2 cells, the protein levels of phosphorylated (p)-ataxia-telangiectasia mutated (ATM), γ-H2A histone family, member X, p-p53, p-checkpoint kinase 2 and p-cell division cycle 25C were evidently increased, indicating that pine needle oil facilitated G2/M arrest in HepG2 cells through the ATM pathway. In response to the treatment with pine needle oil, ATM was activated in HepG2 cells, which subsequently phosphorylated downstream targets and induced G2/M arrest. In summary, the data of the present study indicated that pine needle oil induces G2/M arrest in HepG2 cells by facilitating ATM activation.

Characterization of Vasorelaxant Principles from the Needles of Pinus morrisonicola Hayata

Pinus morrisonicola Hayata, usually called Taiwan five-leaf pine (5LP), is an endemic species in Taiwan and is traditionally used to relieve hypertension symptoms and improve cardiovascular function. In this study, the needle extract of 5LP was fractionated and analyzed by LC/MS/MS to search for possible antihypertensive candidates. In addition, bioassay-guided purification of the bioactive components was performed by Ca²⁺ fluorescent signal (Fluo 4-AM) assays. Two dihydrobenzofuran lignans, pinumorrisonide A (1) and icariside E4 (2), and one acylated flavonoid glycoside, kaempferol 3-O-α-(6‴-p-coumaroylglucosyl-β-1,4-rhamnoside) (3) were characterized from the active fractions. The structure of a new compound 1 was established on the basis of 2D NMR spectroscopic and mass spectrometric analyses, and the known compounds 2 and 3 were identified by comparison of their physical and spectroscopic data with those reported in the literature. The purified compounds 1–3 exhibited significant inhibition of Ca²⁺ fluorescence with IC₅₀ values of 0.71, 0.36, and 0.20 mM, respectively. A mechanism study showed that these compounds showed vasorelaxant effects by blocking the voltage-operated Ca²⁺ channel (VOCC) and inhibiting Ca²⁺ influx to the cytoplasmic. These results suggested that 5LP and the three characterized components could be promising antihypertensive candidates for the use as VOCC blockers.

Chrysin Protects Rat Kidney from Paracetamol-Induced Oxidative Stress, Inflammation, Apoptosis, and Autophagy: A Multi-Biomarker Approach

Paracetamol (PC) is a safe analgesic and antipyretic drug at therapeutic doses, and it is widely used in clinics. However, at high doses, it can induce hepatotoxicity and nephrotoxicity. Chrysin (CR) is a natural flavonoid that has biological activities that include being an antioxidant, an anti-inflammatory, and an anti-cancer agent. The main objective of this study was to investigate the efficacy of CR against PC-induced nephrotoxicity in rats. CR was given orally via feeding needle to male Sprague Dawley rats as a single daily dose of 25 or 50 mg/kg for six days. PC was administered orally via feeding needle as a single dose on the sixth day. PC caused significant glutathione depletion, lipid peroxidation, increased serum toxicity markers (serum urea and creatinine), and reductions in activities of antioxidant enzymes (superoxide dismutase — SOD, catalase — CAT, and glutathione peroxidase — GPx). The renal protective effect of CR was associated with decreasing the regulation of serum renal toxicity markers and increasing the regulation of antioxidant enzyme activities. Additionally, PC led to significant increases in the levels of inflammatory markers including tumour necrosis factor-alpha (TNF-α), interleukin-1β (IL-1β) and interleukin-33 (IL-33). Furthermore, PC induced apoptotic tissue damage by increasing cysteine aspartate-specific protease-3 (caspase-3) activity and autophagic tissue damage by increasing the expression of light chain 3B (LC3B). CR therapy significantly decreased these values in rats. This study demonstrated that CR has antioxidant, anti-apoptotic, anti-inflammatory and anti-autophagic effects on PC-induced kidney toxicity in rats.

Targeting autophagy to sensitive glioma to temozolomide treatment

Temozolomide (TMZ), an alkylating agent, is widely used for treating primary and recurrent high-grade gliomas. However, the efficacy of TMZ is often limited by the development of resistance. Recently, studies have found that TMZ treatment could induce autophagy, which contributes to therapy resistance in glioma. To enhance the benefit of TMZ in the treatment of glioblastomas, effective combination strategies are needed to sensitize glioblastoma cells to TMZ. In this regard, as autophagy could promote cell survival or autophagic cell death, modulating autophagy using a pharmacological inhibitor, such as chloroquine, or an inducer, such as rapamycin, has received considerably more attention. To understand the effectiveness of regulating autophagy in glioblastoma treatment, this review summarizes reports on glioblastoma treatments with TMZ and autophagic modulators from in vitro and in vivo studies, as well as clinical trials. Additionally, we discuss the possibility of using autophagy regulatory compounds that can sensitive TMZ treatment as a chemotherapy for glioma treatment.