Therapeutic potential of natural products in glioblastoma treatment: targeting key glioblastoma signaling pathways and epigenetic alterations

Antitumoral Activity of Cecropia Pachystachya Leaves Extract in Vitro and in Vivo Model of Rat Glioma: Brain and Blood Effects

The aim of this study was to investigate the antiglioma effect of Cecropia pachystachya Trécul (CEC) leaves extract against C6 and U87 glioblastoma (GB) cells and in a rat preclinical GB model. The CEC extract reduced in vitro cell viability and biomass. In vivo, the extract decreased the tumor volume approximately 62%, without inducing systemic toxicity. The deficit in locomotion and memory and an anxiolytic-like behaviors induced in the GB model were minimized by CEC. The extract decreased the levels of reactive oxygen species, nitrites and thiobarbituric acid reactive substances and increased the activity of antioxidant enzymes in platelets, sera and brains of GB animals. The activity of NTPDases, 5'-nucleotidase and adenosine deaminase (ADA) was evaluated in lymphocytes, platelets and serum. In platelets, ATP and AMP hydrolysis was reduced and hydrolysis of ADP and the activity of ADA were increased in the control, while in CEC-treated animals no alteration in the hydrolysis of ADP was detected. In serum, the reduction in ATP hydrolysis was reversed by CEC. In lymphocytes, the increase in the hydrolysis of ATP, ADP and in the activity of ADA observed in GB model was altered by CEC administration. The observed increase in IL-6 and decrease in IL-10 levels in the serum of GB animals was reversed by CEC. These results demonstrate that CEC extract is a potential complementary treatment to GB, decreasing the tumor size, while modulating aspects of redox and purinergic systems.

The Emerging Role of Herbal Medicines in Cancer by Interfering with Posttranslational Modifications

Significance: Herbal medicines have a long history of comprehensive cancer treatment through various posttranslational modifications (PTMs). Recently, emerging evidence revealed that dysregulation of reactive oxygen species (ROS) and ROS-regulated signaling pathways influence cancer initiation, growth, and progression in a paradoxical role with either low levels or increasing levels of basal ROS. However, ROS-triggered modifications of target proteins in the face of ROS-mediated signal transduction are not fully understood in the anticancer therapies of herbal medicines. In this review, we briefly introduce the PTM-dependent regulations of herbal medicines, and then focus on the current ideals that targeting ROS-dependent PTMs via antioxidant and redox signaling pathways can provide a promising strategy in herbal-based anticancer effects. Recent Advances: Advanced development in highly sensitive mass spectrometry-based techniques has helped utilize ROS-triggered protein modifications in numerous cancers. Accumulating evidence has been achieved in laboratory to extensively ascertain the biological mechanism of herbal medicines targeting ROS in cancer therapy. Two general mechanisms underlining ROS-induced cell signaling include redox state and oxidative modification of target protein, indicating a new perspective to comprehend the intricate dialogues between herbal medicines and cancer cellular contexts. Critical Issues: Complex components of herbal medicines limit the benefits of herbal-based cancer therapies. In this review, we address that ROS-dependent PTMs add a layer of proteomic complexity to the cancer through altering the protein structure, expression, function, and localization. Elaborating ROS-triggered PTMs implicated in cell signaling, apoptosis, and transcriptional regulation function, and the possible cellular signaling, has provided important information about the contribution of many ROS targeting herbal therapies in anticancer effects. Continued optimization of proteomic strategies for PTM analysis in herbal medicines is also briefly discussed. Future Directions: Rigorous evaluations of herbal medicines and proteomic strategies are necessary to explore the aberrant regulation of ROS-triggered antioxidant and redox signaling contributing to the novel protein targets and herbal-associated pharmacological issues. These efforts will eventually help develop more herbal drugs as modern therapeutic agents.

The incredible story of ophiobolin A and sphaeropsidin A: two fungal terpenes from wilt-inducing phytotoxins to promising anticancer compounds

Covering: 2000 to 2023This review presents the exceptional story of ophiobolin A (OphA) and sphaeropsidin A (SphA), a sesterterpene and a diterpene, respectively, which were initially isolated as fungal phytotoxins and subsequently shown to possess other interesting biological activities, including promising anticancer activities. Ophiobolin A is a phytotoxin produced by different fungal pathogens, all belonging to the Bipolaris genus. Initially, it was only known as a very dangerous phytotoxin produced by fungi attacking essential cereals, such as rice and barley. However, extensive and interesting studies were carried out to define its original carbon skeleton, which is characterized by a typical 5 : 8 : 5 ring system and shared with fusicoccins and cotylenins, and its phytotoxic activity on host and non-host plants. The biosynthesis of OphA was also defined by describing the different steps starting from mevalonate and through the rearrangement of the acyclic C-25 precursor lead the toxin is obtained. OphA was also produced as a bioherbicide from Drechslera gigantea and proposed for the biocontrol of the widespread and dangerous weed Digitaria sanguinaria. To date, more than sixty ophiobolins have been isolated from different fungi and their biological activities and structure-activity relationship investigated, which were also described using their hemisynthetic derivatives. In the last two decades, thorough studies have been performed on the potential anticancer activity of OphA and its original mode of action, attracting great interest from scientists. Sphaeropsidin A has a similar story. It was isolated as the main phytotoxin from Diplodia cupressi, the causal agent of Italian cypress canker disease, resulting in the loss of millions of plants in a few years in the Mediterranean basin. The damage to the forest, environment and ornamental heritage are noteworthy and economic losses are also suffered by tree nurseries and the wood industry. Six natural analogues of SphA were isolated and several interesting hemisynthetic derivatives were prepared to study its structure-activity relationship. Surprisingly, sphaeropsidin A showed other interesting biological activities, including antibiotic, antifungal, and antiviral. In the last decade, extensive studies have focused on the anticancer activity and original mode of action of SphA. Furthermore, specific hemisynthetic studies enable the preparation of derivatives of SphA, preserving its chromophore, which showed a noteworthy increase in anticancer activity. It has been demonstrated that ophiobolin A and sphaeropsidin A are promising natural products showing potent activity against some malignant cancers, such as brain glioblastoma and different melanomas.

Phytochemical analysis, radical scavenging and glioblastoma U87 cells toxicity studies of stem bark of buckthorn (Rhamnus pentapomica R. Parker)

BACKGROUND

During the past two decades, the correlation between oxidative stress and a variety of serious illnesses such as atherosclerosis, chronic obstructive pulmonary disease (COPD), Alzheimer disease (AD) and cancer has been established. Medicinal plants and their derived phytochemicals have proven efficacy against free radicals and their associated diseases. The current work was aimed to evaluate the phytochemical constituents of Rhamnus pentapomica R. Parker via Gas Chromatography-Mass Spectrometry (GC-MS) and its antioxidant and anti-glioblastoma potentials.

METHODS

The bioactive compounds were analysed in Rhamnus pentapomica R. Parker stem bark extracts by GC-MS analysis, and to evaluate their antioxidant and anti-glioblastoma effects following standard procedures. The stem bark was extracted with 80% methanol for 14 days to get crude methanolic extract (Rp.Cme) followed by polarity directed fractionation using solvents including ethyl acetate, chloroform, butanol to get ethyl acetate fraction (Rp.EtAc), chloroform fraction (Rp.Chf) and butanol fraction (Rp.Bt) respectively. Antioxidant assay was performed using DPPH free radicals and cell viability assay against U87 glioblastoma cancer cell lines was performed via MTT assay.

RESULTS

In GC-MS analysis, thirty-one compounds were detected in Rp.Cme, 22 in Rp.Chf, 24 in Rp.EtAc and 18 compounds were detected in Rp.Bt. Among the identified compounds in Rp.Cme, 9-Octadecenoic acid (Z)-methyl ester (7.73%), Octasiloxane (5.13%) and Heptasiloxane (5.13%), Hexadecanoic acid, methyl ester (3.76%) and Pentadecanoic acid, 14-methyl-, methyl Ester (3.76%) were highly abundant.. In Rp.Chf, Benzene, 1,3-dimethyl- (3.24%) and in Rp.EtAc Benzene, 1,3-dimethyl-(11.29%) were highly abundant compounds. Antioxidant studies revealed that Rp.Cme and Rp.EtAc exhibit considerable antioxidant potentials with IC50 values of 153.53 μg/ml and 169.62 μg/ml respectively. Both fractions were also highly effective against glioblastoma cells with IC50 of 147.64 μg/ml and 76.41ug/ml respectively.

CONCLUSION

Phytochemical analysis revealed the presence of important metabolites which might be active against free radicals and glioblastoma cells. Various samples of the plant exhibited considerable antioxidant and anti-glioblastoma potentials warranting further detailed studies.

Circular RNA circ_0000741/miR-379-5p/TRIM14 signaling axis promotes HDAC inhibitor (SAHA) tolerance in glioblastoma

BACKGROUND

Histone deacetylase (HDAC) inhibitor-based therapeutic drug tolerance is a major obstacle to glioblastoma (GBM) treatment. Meanwhile, non-coding RNAs have been reported to be involved in the regulation of HDAC inhibitor (SAHA) tolerance in some human tumors. However, the relationship between circular RNAs (circRNAs) and SAHA tolerance is still unknown. Herein, we explored the role and mechanism of circ_0000741 on SAHA tolerance in GBM.

METHODS

Circ_0000741, microRNA-379-5p (miR-379-5p), and tripartite motif-containing 14 (TRIM14) level were detected by real-time quantitative polymerase chain reaction (RT-qPCR). (4-5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT), 5-ethynyl-2'-deoxyuridine (EdU), Colony formation, flow cytometry, and transwell assays were used to detect SAHA tolerance, proliferation, apoptosis, and invasion in SAHA-tolerant GBM cells. Western blot analysis of protein levels of E-cadherin, N-cadherin, and TRIM14. After Starbase2.0 analysis, the binding between miR-379-5p and circ_0000741 or TRIM14 was proved using a dual-luciferase reporter. The role of circ_0000741 on drug tolerance was assessed using a xenograft tumor model in vivo.

RESULTS

Circ_0000741 and TRIM14 were upregulated, and miR-379-5p was reduced in SAHA-tolerant GBM cells. Furthermore, circ_0000741 absence reduced SAHA tolerance, suppressed proliferation, invasion, and induced apoptosis in SAHA-tolerant GBM cells. Mechanistically, circ_0000741 might affect TRIM14 content via sponging miR-379-5p. Besides, circ_0000741 silencing enhanced the drug sensitivity of GBM in vivo.

CONCLUSION

Circ_0000741 might accelerate SAHA tolerance by regulating the miR-379-5p/TRIM14 axis, which provided a promising therapeutic target for GBM treatment.

Icariin: A Promising Natural Product in Biomedicine and Tissue Engineering

Among scaffolds used in tissue engineering, natural biomaterials such as plant-based materials show a crucial role in cellular function due to their biocompatibility and chemical indicators. Because of environmentally friendly behavior and safety, green methods are so important in designing scaffolds. A key bioactive flavonoid of the Epimedium plant, Icariin (ICRN), has a broad range of applications in improving scaffolds as a constant and non-immunogenic material, and in stimulating the cell growth, differentiation of chondrocytes as well as differentiation of embryonic stem cells towards cardiomyocytes. Moreover, fusion of ICRN into the hydrogel scaffolds or chemical crosslinking can enhance the secretion of the collagen matrix and proteoglycan in bone and cartilage tissue engineering. To scrutinize, in various types of cancer cells, ICRN plays a decisive role through increasing cytochrome c secretion, Bax/Bcl2 ratio, poly (ADP-ribose) polymerase as well as caspase stimulations. Surprisingly, ICRN can induce apoptosis, reduce viability and inhibit proliferation of cancer cells, and repress tumorigenesis as well as metastasis. Moreover, cancer cells no longer grow by halting the cell cycle at two checkpoints, G0/G1 and G2/M, through the inhibition of NF-κB by ICRN. Besides, improving nephrotoxicity occurring due to cisplatin and inhibiting multidrug resistance are the other applications of this biomaterial.

Pharmacological attributes of Bacopa monnieri extract: Current updates and clinical manifestation

Bacopa monnieri has been used for centuries in Ayurvedic medicine, alone or in combination with other herbs, as a memory and learning enhancer, sedative, and anti-epileptic. This review aimed to highlight the health benefits of B. monnieri extracts (BME), focusing on anti-cancer and neurodegenerative diseases. We examined the clinical studies on phytochemistry and pharmacological application of BME. We further highlighted the mechanism of action of these extracts in varying types of cancer and their therapeutic implications. In addition, we investigated the underlying molecular mechanism in therapeutic interventions, toxicities, safety concerns and synergistic potential in cognition and neuroprotection. Overall, this review provides deeper insights into the therapeutic implications of Brahmi as a lead formulation for treating neurological disorders and exerting cognitive-enhancing effects.

Curcumin piperidone derivatives induce anti-proliferative and anti-migratory effects in LN-18 human glioblastoma cells

Curcumin has demonstrated potential cytotoxicity across various cell lines despite its poor bioavailability and rapid metabolism. Therefore, our group have synthesized curcuminoid analogues with piperidone derivatives, FLDP-5 and FLDP-8 to overcome these limitations. In this study, the analogues were assessed on LN-18 human glioblastoma cells in comparison to curcumin. Results from cytotoxicity assessment showed that FLDP-5 and FLDP-8 curcuminoid analogues caused death in LN-18 cells in a concentration-dependent manner after 24-h treatment with much lower IC50 values of 2.5 µM and 4 µM respectively, which were more potent compared to curcumin with IC50 of 31 µM. Moreover, a significant increase (p < 0.05) in the level of superoxide anion and hydrogen peroxide upon 2-h and 6-h treatment confirmed the oxidative stress involvement in the cell death process induced by these analogues. These analogues also showed potent anti-migratory effects through inhibition of LN-18 cells' migration and invasion. In addition, cell cycle analysis showed that these analogues are capable of inducing significant (p < 0.05) S-phase cell cycle arrest during the 24-h treatment as compared to untreated, which explained the reduced proliferation indicated by MTT assay. In conclusion, these curcuminoid analogues exhibit potent anti-cancer effects with anti-proliferative and anti-migratory properties towards LN-18 cells as compared to curcumin.

Cucurbitane triterpenoid entities derived from Hemsleya penxianensis triggered glioma cell apoptosis via ER stress and MAPK signalling cross-talk

In the present study, six new cucurbitane type compounds, including three triterpenoids hemsleyacins P-R (6-7, 13) and three cucurbitane-type triterpenoid glycosides hemsleyaosides L-N (15-17), along with seventeen known cucurbitacin analogues were separated from the root tuber of Hemsleya penxianensis and elucidated based on NMR and HRESIMS. Then, 23 analogues of three types, namely, polyhydroxy-type (I) (1-7), monohydroxy-type (II) (8-13), and glycosides-type (III) (14-23), were assessed for their antitumor activity and structure-activity relationship analysis (SAR). We determined temozolomide (TMZ)-resistant GBM cell was the most sensitive to the tested compounds, and found hemsleyaoside N (HDN) displayed the best antineoplastic potency. Furthermore, we confirmed the anti-glioma activity of HDN in patient-derived recurrent GBM strains, GBM organoid (GBO) and orthotopic nude mouse models. Investigations exploring the mechanism made clear that HDN induced synchronous activation of UPR and MAPK signaling, which triggered deadly ER stress and apoptosis. Taken together, the potent antitumor activity of HDN warrants further comprehensive evaluation as a novel anti-glioma agent.

A Narrative Review of the Antitumor Activity of Monoterpenes from Essential Oils: An Update

Monoterpenes are a group of natural products that have been widely studied due to their therapeutic potential against various pathologies. These compounds are abundant in the chemical composition of essential oils. Cancer is a term that covers more than 100 different types of malignant diseases and is among the leading causes of death in the world. Therefore, the search for new pharmacotherapeutic options applicable to cancer is urgent. In this review, studies on the antitumor activity of monoterpenes found in essential oils were selected, and botanical, chemical, and pharmacological aspects were discussed. The most investigated monoterpenes were carvacrol and linalool with highly significant in vitro and in vivo tumor inhibition in several types of cancers. The action mechanisms of these natural products are also presented and are wildly varied being apoptosis the most prevalent followed by cell cycle impairment, ROS production, autophagy, necroptosis, and others. The studies reported here confirm the antitumor properties of monoterpenes and their anticancer potential against various types of tumors, as demonstrated in in vitro and in vivo studies using various types of cancer cells and tumors in animal models. The data described serve as a reference for the advancement in the mechanistic studies of these compounds and in the preparation of synthetic derivatives or analogues with a better antitumor profile.

Phlomis fruticosa L. exerts in vitro antineurodegenerative and antioxidant activities and induces prooxidant effect in glioblastoma cell line

Despite the significant advances in drug development we are witnessing the inability of health systems to combat both neurodegenerative diseases and cancers, especially glioblastoma. Hence, natural products are comprehensively studied in order to provide novel therapeutic options. This study aimed to explore anti-neurodegenerative and anti-glioblastoma potential of extract of Phlomis fruticosa L. using in vitro model systems. It was found that the methanol extract of P. fruticosa was able to efficiently reduce activities of enzymes linked to neurodegenerative disease including acetylcholinesterase, butyrylcholinesterase and tyrosinase. Furthermore, P. fruticosa extract has shown excellent antioxidant potential, as evidenced by six different methods. Analysis of cytotoxic effect of P. fruticosa extract on A172 glioblastoma cell line revealed that the concentration of the extract necessary for 50 % inhibition of A172 growth (IC₅₀) was 710 μg/mL. The extract did not induce changes in proliferation and morphology of A172 glioblastoma cells. On the other side, production of ROS was increased in A172 cells treated with the extract. Observed cytotoxic effect of P. fruticosa extract might be based on increase in ROS generation upon treatment. Quantitative chemical analysis revealed the presence of twelve different polyphenols with the cis 3-O-caffeoylquinic acid being the most abundant. This study provided scientific evidence for further exploration of P. fruticosa as a promising natural anti-neurodegenerative therapeutic option.

Oxyphyllanene B overcomes temozolomide resistance in glioblastoma: Structure-activity relationship and mitochondria-associated ER membrane dysfunction

BACKGROUND

The identification of novel therapeutic candidates from natural products for the development of chemoresistant glioblastoma multiforme (GBM) treatment has been a highly significant and effective strategy.

PURPOSE

Sesquiterpenes are a class of naturally occurring 15-carbon isoprenoid compounds, and several types of sesquiterpenes have the ability to induce growth inhibition and apoptosis in a variety of cancer cell lines. In the present study, 56 sesquiterpenes of five types, namely, eudesmane-type (I) (1-24), eremophilane-type (II) (25-32), cadinane-type (III) (33-41), guaiane-type (IV) (42-49), and oplopanone-type (V) (50-56), were screened for their antiglioma activity, structure-activity relationship analysis (SAR), and underlying mechanism based on patient-derived recurrent GBM strains, patient-derived GBM cell sphere, GBM organoid (GBO) models, and temozolomide (TMZ)-resistant GBM cell lines.

RESULTS

We found that compound 12 (oxyphyllanene B, OLB) showed the most potent antiglioma activity, and we confirmed that OLB could induce apoptosis in a time- and dose-dependent manner in TMZ-resistant GBM cells and GBOs. SAR announced that the presence of an α, β-unsaturated carbonyl moiety was likely to enhance cytotoxic activities. Mechanistic studies demonstrated that OLB induced abnormal changes in ER and mitochondria-associated membrane (MAM) networks, which triggered ER stress, mitochondrial dysfunction, and apoptosis. Furthermore, our findings suggested that OLB-triggered PACS2 activation might form a committed step to disrupt ER-mitochondria communication and showed for the first time that the expression levels of PACS2 might positively correlate with the progression and chemotherapy resistance of glioma.

CONCLUSION

Our results indicated that OLB might be a promising candidate for treating TMZ-resistant GBM cells by activating PACS2, which triggered a crucial event to promote the disruption of ER-mitochondria communication and overcome chemotherapy resistance of GBM.

Medicinal Plants for Glioblastoma Treatment

Glioblastoma, an aggressive brain cancer, demonstrates the least life expectancy among all brain cancers. Because of the regulation of diverse signaling pathways in cancers, the chemotherapeutic approaches used to suppress their multiplication and spreading are restricted. Sensitivity towards chemotherapeutic agents has developed because of the pathological and drug-evading abilities of these diverse mechanisms. As a result, the identification and exploration of strategies or treatments, which can overcome such refractory obstacles to improve glioblastoma response to treatment as well as recovery, is essential. Medicinal herbs contain a wide variety of bioactive compounds, which could trigger aggressive brain cancers, regulate their anti-cancer mechanisms and immune responses to assist in cancer elimination, and cause cell death. Numerous tumor-causing proteins, which facilitate invasion as well as metastasis of cancer, tolerance of chemotherapies, and angiogenesis, are also inhibited by these phytochemicals. Such herbs remain valuable for glioblastoma prevention and its incidence by effectively being used as anti-glioma therapies. This review thus presents the latest findings on medicinal plants using which the extracts or bioactive components are being used against glioblastoma, their mechanism of functioning, pharmacological description as well as recent clinical studies conducted on them.

LncRNA RBPMS-AS1 promotes NRGN transcription to enhance the radiosensitivity of glioblastoma through the microRNA-301a-3p/CAMTA1 axis

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RBPMS-AS1 and CAMTA1 are lowly expressed in GBM patients.

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RBPMS-AS1 and CAMTA1 enhance the radiosensitivity of GBM.

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miR-301a-3p diminishes the radiosensitivity of GBM.

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RBPMS-AS1 enhances CAMTA1 expression in GBM cells through sponging miR-301a-3p.

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CAMTA1 promotes NRGN transcription.

Objective

Glioblastoma (GBM) is the most frequent brain malignancy with high incidence, and long noncoding RNAs (lncRNAs) exerts functions in GBM. In this research, we focused on the capabilities of lncRNA RBPMS-AS1 in radiosensitivity of GBM.

Methods

RBPMS-AS1 and CAMTA1 expression levels were determined in GBM tissues and cells. StarBase v3.0 database was searched for predicting miRNAs that simultaneously bound to RBPMS-AS1 and CAMTA1. pcDNA3.1-RBPMS-AS1, pcDNA3.1-CAMTA1, miR-301a-3p mimic, or pcDNA3.1-RBPMS-AS1/pcDNA3.1-CAMTA1 and miR-301a-3p mimic were transfected into GBM cells to test radiosensitivity, cell proliferation and apoptosis. The interactions of miR-301a-3p with RBPMS-AS1 and CAMTA1, as well as CAMTA1 and NRGN, were confirmed. In vivo imaging technology was utilized to detect tumor growth in orthotopic xenograft tumors, and Ki67 expression was tested in intracranial tumors.

Results

RBPMS-AS1 and CAMTA1 levels were reduced in GBM tissues and cells. miR-301a-3p had a binding site with both RBPMS-AS1 and CAMTA1 and it was the most significantly-upregulated one. Upregulation of RBPMS-AS1 or CAMTA1 enhanced the radiosensitivity and cell apoptosis while suppressing proliferation of GBM cells. Conversely, miR-301a-3p overexpression diminished the radiosensitivity and cell apoptosis while inducing proliferation of GBM cells. Overexpression of RBPMS-AS1 or CAMTA1 reversed the effects of overexpressed miR-301a-3p in GBM cells. Mechanistically, RBPMS-AS1 enhanced CAMTA1 expression in GBM cells through sponging miR-301a-3p, and CAMTA1 promoted NRGN expression. In animal experiments, overexpressed RBPMS-AS1 inhibited tumor growth and the positive expression of Ki67 both before and after radiation therapy.

Conclusion

RBPMS-AS1 promotes NRGN transcription through the miR-301a-3p/CAMTA1 axis and enhances the radiosensitivity of GBM.

SOX transcription factors and glioma stem cells: Choosing between stemness and differentiation

Glioblastoma (GBM) is the most common, most aggressive and deadliest brain tumor. Recently, remarkable progress has been made towards understanding the cellular and molecular biology of gliomas. GBM tumor initiation, progression and relapse as well as resistance to treatments are associated with glioma stem cells (GSCs). GSCs exhibit a high proliferation rate and self-renewal capacity and the ability to differentiate into diverse cell types, generating a range of distinct cell types within the tumor, leading to cellular heterogeneity. GBM tumors may contain different subsets of GSCs, and some of them may adopt a quiescent state that protects them against chemotherapy and radiotherapy. GSCs enriched in recurrent gliomas acquire more aggressive and therapy-resistant properties, making them more malignant, able to rapidly spread. The impact of SOX transcription factors (TFs) on brain tumors has been extensively studied in the last decade. Almost all SOX genes are expressed in GBM, and their expression levels are associated with patient prognosis and survival. Numerous SOX TFs are involved in the maintenance of the stemness of GSCs or play a role in the initiation of GSC differentiation. The fine-tuning of SOX gene expression levels controls the balance between cell stemness and differentiation. Therefore, innovative therapies targeting SOX TFs are emerging as promising tools for combatting GBM. Combatting GBM has been a demanding and challenging goal for decades. The current therapeutic strategies have not yet provided a cure for GBM and have only resulted in a slight improvement in patient survival. Novel approaches will require the fine adjustment of multimodal therapeutic strategies that simultaneously target numerous hallmarks of cancer cells to win the battle against GBM.

Phragmunis a suppresses glioblastoma through the regulation of MCL1-FBXW7 by blocking ELK1-SRF complex-dependent transcription

Glioblastoma (GBM) is a highly aggressive brain tumor. During screening work, we found a new compound named phragmunis A (PGA), which is derived from the fruitbody of Trogia venenata, exhibits a potential cytotoxic effect on patient-derived recurrent GBM cells and temozolomide (TMZ)-resistant cell lines. The present study was designed to investigate the potential molecular mechanism of the anti-glioma effects of PGA in vitro and in vivo. Studies investigating the mechanism revealed that PGA diminished the binding efficiency of ETS family of transcription factor (ELK1) and Serum response factor (SRF), and suppressed ELK1-SRF complex-dependent transcription, which decreased the transcriptional levels of downstream genes Early growth response protein 1 (EGR1)-Polycomb ring finger (BMI1), thus inducing the imbalanced regulation between Myeloid cell leukaemia-1 (MCL1) and F-Box and WD repeat domain containing 7 (FBXW7). Finally, orthotopic xenograft models were established to confirm the anti-glioma effect of PGA on tumour growth. We showed, for the first time, that the cytotoxic effects of PGA occurred by inducing MCL1 inhibition and FBXW7 activation by blocking ELK1-SRF complex-dependent transcription. The blockage of ELK1-mediated transcription resulted in the suppression of EGR1-BMI1, which led to the upregulation of FBXW7 expression and downregulation of MCL1. These findings suggested that PGA could be a therapeutic drug candidate for the treatment of recurrent GBM by targeting the ELK1-SRF complex.

Moschamindole induces glioma cell apoptosis by blocking Mia40-dependent mitochondrial intermembrane space assembly and oxidative respiration

Glioblastoma multiforme (GBM) is the most frequent, lethal, and aggressive tumor of the central nervous system in adults. In this study, we found for the first time that moschamindole (MCD), a rare phenolic amide with 8/6/6/5/5 rings, is a major bioactive constituent derived from Phragmites communis Trin (Poaceae) that exhibits a potential cytotoxic effect on both TMZ-resistant GBM cell lines and xenograft models. MCD-induced intrinsic apoptosis signals and mitochondrial dysfunction were confirmed by cell cycle arrest, caspase-3/7 activation, and membrane potential depolarization. Furthermore, investigations exploring the mechanism showed that MCD specifically inhibits Mia40-mediated oxidative folding of mitochondrial intermembrane space (IMS) proteins via PCR assay and immunoblot analysis. MCD relies on its positive charge to associate with mitochondrial oxidative respiration, thus blocking energy metabolism and inducing apoptosis. Overexpression and upregulation of Mia40 were proven to reverse MCD-induced apoptosis and were correlated with the chemoresistance of GBM in vitro and in vivo, respectively. Taken together, our study demonstrates that Mia40 is a potential target of the chemoresistance of glioblastoma and suggests that MCD might be a potential agent for the individualized treatment of chemoresistant GBM based on mitochondrial metabolic characteristics and Mia40 expression.

Curcumin Regulates Cancer Progression: Focus on ncRNAs and Molecular Signaling Pathways

Curcumin [(1E,6E) ‑1,7‑bis(4‑hydroxy‑3‑methoxyphenyl) hepta‑1,6‑diene‑3,5‑ dione] is a natural polyphenol derived from the rhizome of the turmeric plant Curcuma longa. Accumulated evidences have presented curcumin’s function in terms of anti-inflammatory, antioxidant properties, and especially anti-tumor activities. Studies demonstrated that curcumin could exert anti-tumor activity via multiple biological signaling pathways, such as PI3K/Akt, JAK/STAT, MAPK, Wnt/β-catenin, p53, NF-ĸB and apoptosis related signaling pathways. Moreover, Curcumin can inhibit tumor proliferation, angiogenesis, epithelial-mesenchymal transition (EMT), invasion and metastasis by regulating tumor related non-coding RNA (ncRNA) expression. In this review, we summarized the roles of curcumin in regulating signaling pathways and ncRNAs in different kinds of cancers. We also discussed the regulatory effect of curcumin through inhibiting carcinogenic miRNA and up regulating tumor suppressive miRNA. Furthermore, we aim to illustrate the cross regulatory relationship between ncRNA and signaling pathways, further to get a better understanding of the anti-tumor mechanism of curcumin, thus lay a theoretical foundation for the clinical application of curcumin in the future.

Challenges and Perspectives of Standard Therapy and Drug Development in High-Grade Gliomas

Despite their low incidence rate globally, high-grade gliomas (HGG) remain a fatal primary brain tumor. The recommended therapy often is incapable of resecting the tumor entirely and exclusively targeting the tumor leads to tumor recurrence and dismal prognosis. Additionally, many HGG patients are not well suited for standard therapy and instead, subjected to a palliative approach. HGG tumors are highly infiltrative and the complex tumor microenvironment as well as high tumor heterogeneity often poses the main challenges towards the standard treatment. Therefore, a one-fit-approach may not be suitable for HGG management. Thus, a multimodal approach of standard therapy with immunotherapy, nanomedicine, repurposing of older drugs, use of phytochemicals, and precision medicine may be more advantageous than a single treatment model. This multimodal approach considers the environmental and genetic factors which could affect the patient's response to therapy, thus improving their outcome. This review discusses the current views and advances in potential HGG therapeutic approaches and, aims to bridge the existing knowledge gap that will assist in overcoming challenges in HGG.

Immunodiagnosis and Immunotherapeutics Based on Human Papillomavirus for HPV-Induced Cancers

Infection with human papillomavirus (HPV) is one of the main causes of malignant neoplasms, especially cervical, anogenital, and oropharyngeal cancers. Although we have developed preventive vaccines that can protect from HPV infection, there are still many new cases of HPV-related cancers worldwide. Early diagnosis and therapy are therefore important for the treatment of these diseases. As HPVs are the major contributors to these cancers, it is reasonable to develop reagents, kits, or devices to detect and eliminate HPVs for early diagnosis and therapeutics. Immunological methods are precise strategies that are promising for the accurate detection and blockade of HPVs. During the last decades, the mechanism of how HPVs induce neoplasms has been extensively elucidated, and several oncogenic HPV early proteins, including E5, E6, and E7, have been shown to be positively related to the oncogenesis and malignancy of HPV-induced cancers. These oncoproteins are promising biomarkers for diagnosis and as targets for the therapeutics of HPV-related cancers. Importantly, many specific monoclonal antibodies (mAbs), or newly designed antibody mimics, as well as new immunological kits, devices, and reagents have been developed for both the immunodiagnosis and immunotherapeutics of HPV-induced cancers. In the current review, we summarize the research progress in the immunodiagnosis and immunotherapeutics based on HPV for HPV-induced cancers. In particular, we depict the most promising serological methods for the detection of HPV infection and several therapeutical immunotherapeutics based on HPV, using immunological tools, including native mAbs, radio-labelled mAbs, affitoxins (affibody-linked toxins), intracellular single-chain antibodies (scFvs), nanobodies, therapeutical vaccines, and T-cell-based therapies. Our review aims to provide new clues for researchers to develop novel strategies and methods for the diagnosis and treatment of HPV-induced tumors.

Oxidative Stress and Cancer Development: Are Noncoding RNAs the Missing Links?

Significance: It is now clear that genetic changes underlie the basis of cancer, and alterations in functions of multiple genes are responsible for the process of tumorigenesis. Besides the classical genes that are usually implicated in cancer, the role of noncoding RNAs (ncRNAs) and reactive oxygen species (ROS) as independent entitites has also been investigated. Recent Advances: The microRNAs and long noncoding RNAs (lncRNAs), two main classes of ncRNAs, are known to regulate many aspects of tumor development. ROS, generated during oxidative stress and pathological conditions, are known to regulate every step of tumor development. Conversely, oxidative stress and ROS producing agents can suppress tumor development. The malignant cells normally produce high levels of ROS compared with normal cells. The interaction between ROS and ncRNAs regulates the expression of multiple genes and pathways implicated in cancer, suggesting a unique mechanistic relationship among ncRNA-ROS-cancer. The mechanistic relationship has been reported in hepatocellular carcinoma, glioma, and malignancies of blood, breast, colorectum, esophagus, kidney, lung, mouth, ovary, pancreas, prostate, and stomach. The ncRNA-ROS regulate several cancer-related cell signaling pathways, namely, protein kinase B (AKT), epidermal growth factor receptor (EGFR), forkhead box O3 (FOXO3), kelch-like ECH-associated protein 1 (Keap1), nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB), nuclear factor erythroid 2-related factor 2 (Nrf2), p53, phosphatase and tensin homologue (PTEN), and wingless-related integration site (Wnt)/glycogen synthase kinase-3 beta (GSK3β). Critical Issues: To date, most of the reports about ncRNA-oxidative stress-carcinogenesis relationships are based on cell lines. The mechanistic basis for this relationship has not been completely elucidated. Future Directions: Attempts should be made to explore the association of lncRNAs with ROS. The significance of the ncRNA-oxidative stress-carcinogenesis interplay should also be explored through studies in animal models.

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.

Simultaneous impact of atorvastatin and mesenchymal stem cells for glioblastoma multiform suppression in rat glioblastoma multiform model

Glioblastoma multiform (GBM) is known as an aggressive glial neoplasm. Recently incorporation of mesenchymal stem cells with anti-tumor drugs have been used due to lack of immunological responses and their easy accessibility. In this study, we have investigated the anti-proliferative and apoptotic activity of atorvastatin (Ator) in combination of mesenchymal stem cells (MSCs) on GBM cells in vitro and in vivo. The MSCs isolated from rats and characterized for their multi-potency features. The anti-proliferative and migration inhibition of Ator and MSCs were evaluated by MTT and scratch migration assays. The annexin/PI percentage and cell cycle arrest of treated C6 cells were evaluated until 72 h incubation. The animal model was established via injection of C6 cells in the brain of rats and subsequent injection of Ator each 3 days and single injection of MSCs until 12 days. The growth rate, migrational phenotype and cell cycle progression of C6 cells decreased and inhibited by the interplay of different factors in the presence of Ator and MSCs. The effect of Ator and MSCs on animal models displayed a significant reduction in tumor size and weight. Furthermore, histopathology evaluation proved low hypercellularity and mitosis index as well as mild invasive tumor cells for perivascular cuffing without pseudopalisading necrosis and small delicate vessels in Ator + MSCs condition. In summary, Ator and MSCs delivery to GBM model provides an effective strategy for targeted therapy of brain tumor.

CircFBXW7 alleviates glioma progression through regulating miR-23a-3p/PTEN axis

Increasing evidence has confirmed that circular RNAs (circRNAs) are involved in regulating the development and progression of various tumors. The aim of this study was to examine the effect of circFBXW7 on the progression of glioma and to determine its underlying mechanism. qRT-PCR was performed to measure the expression of circFBXW7, miR-23a-3p, and PTEN in tissues and cell lines of glioma. The proliferation ability of glioma cells was examined using the CCK-8 assay. Glioma cell migration and invasion capacity were detected using Transwell assays. The dual-luciferase reporter gene assay was employed to examine the correlation between miR-23a-3p and circFBXW7 or PTEN. The expression levels of the related genes were determined using western blotting analysis. A glioma xenograft tumor model was employed to evaluate the functional roles of circFBXW7 in vivo. CircFBXW7 was found to be aberrantly downregulated in glioma tumor tissues and cell lines. Overexpression of circFBXW7 was found to significantly inhibit the proliferation, migration and invasion ability of the glioma cells. Moreover, bioinformatic analysis and dual-luciferase reporter assays confirmed that circFBXW7 can directly target miR-23a-3p, which then blocks the binding of miR-23a-3p to the 3' un-translated region (UTR) of PTEN. Mechanically, circFBXW7 suppresses cell proliferation and metastasis in glioma by sponging miR-23a-3p, resulting in elevated PTEN expression. In addition, in vivo experiments also confirmed that circFBXW7 overexpression effectively halts tumor growth and metastasis. Consistent with the in vitro observations, circFBXW7 overexpression significantly decreased miR-23a-3p, Ki-67, and N-cadherin, as well as increased PTEN and E-cadherin levels. Our results revealed that circFBXW7 exhibits antiproliferative and antimetastasis activities via sponging miR-23a-3p to elevate PTEN expression in glioma, which may offer a novel target for clinical therapy and diagnosis of glioma.

β-Caryophyllene Inhibits Cell Proliferation through a Direct Modulation of CB2 Receptors in Glioblastoma Cells

Glioblastomas are aggressive cancers characterized by uncontrolled proliferation and inflammation. b-caryophyllene (BCP) is a cannabinoid receptor 2 (CB2) agonist that showed an important anti-inflammatory effect through the interaction of CB2 and peroxisome proliferator-activated receptor gamma (PPARg) receptors. BCP effects were investigated in an in vitro model of glioblastoma. U-373 and U87, derived from a human glioblastoma, and human glioma stem-like cells (GSCs) were treated with BCP at different doses and time-points. AM360, a specific CB2 antagonist, was added 2 h before BCP treatment. BCP showed a significant anti-proliferative effect, reducing cell viability, inhibiting cell cycle, and increasing apoptosis, as demonstrated by Tunel assay, caspase-3 and caspase -9 activation. In addition, the pro-apoptotic BAX expression was increased, whereas the anti-apoptotic Bcl-2 expression was reduced. Treatment with BCP decreased Beclin-1, LC3 and p62/SQSTM1 expression, indicating a possible switch of autophagy to apoptosis. BCP’s anti-inflammatory effect was demonstrated by NF-κB reduction, PPARg activation and TNF-a decrease; BCP significantly reduced Jun N-Terminal Kinase (JNK) expression as a consequence of TNF-α inhibition. AM360 abrogated BCP effects, thus demonstrating the BCP mechanism of action through the CB2 receptor. These findings let us hypothesize that BCP may act as a tumor suppressor in glioblastoma, acting on CB2 receptor and modulating JNK.

Epigenetic Research in Stem Cell Bioengineering-Anti-Cancer Therapy, Regenerative and Reconstructive Medicine in Human Clinical Trials

The epigenome denotes all the information related to gene expression that is not contained in the DNA sequence but rather results from chemical changes to histones and DNA. Epigenetic modifications act in a cooperative way towards the regulation of gene expression, working at the transcriptional or post-transcriptional level, and play a key role in the determination of phenotypic variations in cells containing the same genotype. Epigenetic modifications are important considerations in relation to anti-cancer therapy and regenerative/reconstructive medicine. Moreover, a range of clinical trials have been performed, exploiting the potential of epigenetics in stem cell engineering towards application in disease treatments and diagnostics. Epigenetic studies will most likely be the basis of future cancer therapies, as epigenetic modifications play major roles in tumour formation, malignancy and metastasis. In fact, a large number of currently designed or tested clinical approaches, based on compounds regulating epigenetic pathways in various types of tumours, employ these mechanisms in stem cell bioengineering.