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Glioblastoma (GBM) is an aggressive form of brain tumor with a median survival of approximately 12 months. With no new drugs in the last few decades and limited success in clinics for known therapies, drug repurposing is an attractive choice for its treatment. Here, we examined the efficacy of pyronaridine (PYR), an anti-malarial drug in GBM cells. PYR induced anti-proliferative activity in GBM cells with IC50 ranging from 1.16 to 6.82 µM. Synergistic activity was observed when PYR was combined with Doxorubicin and Ritonavir. Mechanistically, PYR triggered mitochondrial membrane depolarization and enhanced the ROS levels causing caspase-3 mediated apoptosis. PYR significantly decreased markers associated with proliferation, EMT, hypoxia, and stemness and upregulated the expression of E-cadherin. Interestingly, PYR induced the expression of intracellular as well as secretory Par-4, a tumor suppressor in GBM cells, which was confirmed using siRNA. Notably, Par-4 levels in plasma samples of GBM patients were significantly lower than normal healthy volunteers. Thus, our study demonstrates for the first time that PYR can be repurposed against GBM with a novel mechanism of action involving Par-4. Herewith, we discuss the role of upregulated Par-4 in a highly interconnected signaling network thereby advocating its importance as a therapeutic target.

Sclerotium rolfsii lectin (SRL) exerts apoptotic effect against various cancer cells and an antitumor activity on mice with colon and breast cancer xenografts. The current study aimed to explore its exquisite carbohydrate specificity on human peripheral blood mononuclear cells (PBMCs) and leukemic T-cells. SRL, showed strong binding (>98%) to resting/activated PBMCs, leukemic Molt-4 and Jurkat cell lines. The glycans mediated binding to these cells was effectively blocked by mucin and fetuin, exhibiting 97% and 94% inhibition respectively. SRL showed mitogenic stimulation of PBMCs at 10 μg/ml as determined by thymidine incorporation assay. In contrast, lectin induced a dose dependent growth inhibition of Molt-4 cells with 58% inhibition at 25 μg/ml. Many common membrane receptors in activated PBMCs, Molt 4 and Jurkat cells were identified by lectin blotting. However, membrane receptors that are recognized by SRL in normal resting PBMCs were totally different and are high molecular weight glycoproteins. Treatment of membrane receptors with glycosidases prior to lectin probing, revealed that fucosylated Thomsen–Friedenreich(TF) antigen glycans are increasingly expressed on transformed Molt-4 leukemic cells compared to other cells. The findings highlight the opposite effects of SRL on transformed and normal hematopoietic cells by recognizing different glycan-receptors. SRL has promising potential for diagnostics and therapeutic applications in leukaemia.

Background High Risk Human Papilloma Viruses (HR-HPV) recurrently infect women having Human Immunodeficiency Virus − 1 (HIV-1)infection. Transforming HPV E6 and E7 genes promote invasive cancers and interact with Notch-1receptor. Concomitantly, HIV-1 Tat binds to EGF motifs within the Notch-1extracellular domain. HR-HPV infection activates Notch-1 signalling. Permissive HIV-1entry into the cervix is allowed. Notch-1 inhibitors may offer solace to the aggressive cancer phenotype in HIV-1 positive women. Still, the molecular cross talk between different oncogenes within the Notch-1pathway during HIV-1/HPV-16 + co-infections has not been elucidated. Methods Adherent cervical tumor derived cell lines-CaSki cell line (with inherent HPV16+ sequence and endogenous Notch-1 activity) and C33A cell line (cervical cancer phenotype, HPV -ve for HPV DNA and RNA) were used. Plasmids (pLEGFPN1 encoding HIV-1 Tat and pNL 4 − 3 encoding HIV-1(full HIV-1 genome), were transfected at 600 ng/mL into the above mentioned cell lines, in order to examine independent effects of HIV-1 Tat and HIV-1 transfection in HPV-16+ cervical cancer cells. We performed western blotting, cell cycle analysis and RT-qPCR post transfection. Three sets of independent experiments were analyzed by Graph Pad Prism 5. Statistical significance was calculated using Student t -test. Data expressed as mean ± standard deviation (SD). p values ≤ 0.05* were considered statistically significant. Results HIV-1 Tat and HIV-1 inhibited Notch-1expression, with differential effects on EGFR when comparing C33A and CaSki cell lines. CDK2 induction in Tat transfected CaSki cells, showed concomitant G0/G1 phase accumulation favouring cancer progression. Notch-1 inhibition shut off significant Cyclin D expression with a significant p21 induction and increased G2-M cell population in CaSki cells. On the contrary, HIV-1 infection utilized Hes-1-EGFR-CyclinD-p21axis, G2-M arrest, DDR response and cancer progression. Conclusion Our study highlights for the first time that HIV-1 Tat and/or HIV-1 driven cancers in HPV-16+ CaSki cells, show Notch-1 suppression and CDK2 dependent activity. HIV-1 Tat activates Hes-1 amplifying the EGFR gene which improves the aggressive state possibly through irreversible oxidative-stress induced senescence. HIV-1, favours cancer progression through its CXCR4 receptor, responsible for unbridled mitosis, G2-M arrest and damaged DNA response (DDR). Treatment of CaSki cells with a Notch-1 inhibitor, DAPT showed marginal recovery in p21expression with Go/G1 and S phase recovery.

Introduction: Radiation exposure to brain is known to cause cognitive deficits. Aim of the current study was to investigate whether lithium protects against radiation. It was further investigated whether this protective effect is associated with neuritogenesis and altered Neural Cell Adhesion Molecule (NCAM) expression. Materials and Methods: Human neuroblastoma cell line, SK-N-MC was exposed to gamma radiation alone and after 24 h pretreatment with lithium. Cells were scored for viability by MTT assay and checked for apoptotic changes by flow cytometry (FCM). Geimsa stained cells were scored for number of cells bearing neuritis and length of neuritis. Real time PCR was used to measure levels of NCAM transcript in the cells. Results: Radiation exposure of 5 Gray resulted in significant decrease in cell viability. Pretreatment with lithium rescued cells from radiation- induced toxicity as indicated by MTT assay and by FCM analysis. Morphological observations suggested radiation caused increase in neurite lengths and decrease in number of cells bearing neurites. This was reversed by lithium treatment. Several fold decrease in NCAM expression was observed post radiation exposure which was reversed by lithium pretreated cells. Conclusion: Lithium protects neuronal cells against radiation damage. The protective effect of lithium is associated with change in differentiation status of cells as indicated by neuritogenesis and with alteration in expression of NCAM, a molecule known to be associated with neurite formation.

Plasmodium falciparum malaria is the most severe form of malaria with several complications. The malaria pigment‐hemozoin (Hz) is associated with severe anemia, cytokine dysfunction, and immunosuppression, thus making it an interesting target for developing new strategies for antimalarial therapy. Monocytes (MO) in circulation actively ingest Hz released by Plasmodium parasites and secrete pro‐ and anti‐inflammatory cytokines. M1 and M2 types represent the two major forms of MO/macrophages (MQ) with distinct phenotypes and opposing functions. Imbalance in the polarization of these types is reported in many infectious diseases. Though the association of Hz with immunosuppression is well documented, its role in activation of MO in context of M1/M2 phenotypes remains to be addressed. We report here that natural Hz drives human MO toward M2‐like phenotype as evidenced by the expression of M2 signature markers. Hz‐fed MO showed elevated transcript and secreted level of IL‐10, CCL17, CCL1, expression of mannose‐binding lectin receptor (CD206), and arginase activity. Hz attenuated HLA‐DR expression, nitric oxide, and reactive oxygen species production, which are the features of M1 phenotype. Our data also implicate the involvement of p38 MAPK, PI3K/AKT, and NF‐κB signaling pathways in skewing of Hz‐fed MO toward M2‐like type and suppression of mitogen‐stimulated lymphocyte proliferation. Importantly, antimalarial drugs—chloroquine and artemisinin—partially reversed activation of Hz‐induced MO toward M2‐like phenotype. Considering the limitations in the current therapeutic options for malaria, we propose that these drugs may be re‐examined for their potential as immunomodulators and candidates for adjunctive treatment in malaria.

The phosphatidylinositol 3-kinase/Akt/mammalian target of rapamycin signaling pathway is crucial for tumor survival, proliferation, and progression, making it an attractive target for therapeutic intervention. In glioblastoma, activated mammalian target of rapamycin promotes invasive phenotype and correlates with poor patient survival. A wide range of mammalian target of rapamycin inhibitors are currently being evaluated for cytotoxicity and anti-proliferative activity in various tumor types but are not explored sufficiently for controlling tumor invasion and recurrence. We recently reported that mammalian target of rapamycin inhibitors—rapamycin, temsirolimus, torin 1, and PP242—suppressed invasion and migration promoted by tumor necrosis factor-alpha and phorbol-myristate-acetate in glioblastoma cells. As aggressive invasion and migration of tumors are associated with mesenchymal and stem-like cell properties, this study aimed to examine the effect of mammalian target of rapamycin inhibitors on these features in glioblastoma cells. We demonstrate that temsirolimus and torin 1 effectively reduced the constitutive as well as phorbol-myristate-acetate/oncostatin-M-induced expression of mesenchymal markers (fibronectin, vimentin, and YKL40) and neural stem cell markers (Sox2, Oct4, nestin, and mushashi1). The inhibitors significantly abrogated the neurosphere-forming capacity induced by phorbol-myristate-acetate and oncostatin-M. Furthermore, we demonstrate that the drugs dephosphorylated signal transducer and activator transcription factor 3, a major regulator of mesenchymal and neural stem cell markers implicating the role of signal transducer and activator transcription factor 3 in the inhibitory action of these drugs. The findings demonstrate the potential of mammalian target of rapamycin inhibitors as “stemness-inhibiting drugs” and a promising therapeutic approach to target glioma stem cells.

Glioblastoma (GBM) is the most aggressive type of brain tumors in adults with survival period

Glucose regulated protein 78 (GRP78) has recently been suggested to be associated with drug resistance in breast cancer patients. However, the precise role of GRP78 in drug resistance and the involved signaling pathways are not clearly understood. In the present study, we show that among a panel of drugs, namely Paclitaxel (TAX), Doxorubicin (DOX), 5-fluorouracil (5-FU), UCN-01 and Tamoxifen (TAM) used, TAM alone up-regulated the expression of GRP78 significantly and induced apoptosis in MCF-7 and MDA-MB-231 cells. Interestingly, inhibition of GRP78 by a specific pharmacological inhibitor, VER-155008 augmented TAM-induced apoptosis, and overexpression of GRP78 rendered the cells resistant to TAM-induced cell death suggesting a role for GRP78 in TAM-induced cytotoxicity. Mechanistically, the expression of phosphorylated AKT as determined by Western blot analyses revealed that TAM selectively upregulated phosphorylation of AKT at Thr308 but not at Ser473, and siRNA silencing of GRP78 resulted in inhibition of AKT phosphorylation at Thr308 but not at Ser473. Further, a GRP78 inhibitor, VER155008 inhibited TAM-induced phosphorylation of GSK3β, a downstream substrate of AKT. These results, thus suggests a role for GRP78 in TAM-induced AKT activation. Additionally, co-localization studies by immunofluorescence, and immunoprecipitation experiments demonstrated a complex formation of AKT and GRP78. Furthermore, in glucose-free medium, the cells were sensitized to TAM-induced cell death that was associated with reduced AKT phosphorylation at Thr308, thus strengthening the association of AKT regulation with drug response. Collectively, our findings identify a role of GRP78 in AKT regulation in response to TAM in breast cancer cells.