Y. Rajesh

Gold nanorod embedded reduction responsive block copolymer micelle-triggered drug delivery combined with photothermal ablation for targeted cancer therapy.

BACKGROUND Gold nanorods, by virtue of surface plasmon resonance, convert incident light energy (NIR) into heat energy which induces hyperthermia. We designed unique, multifunctional, gold nanorod embedded block copolymer micelle loaded with GW627368X for targeted drug delivery and photothermal therapy. METHODS Glutathione responsive diblock co-polymer was synthesized by RAFT process forming self-assembled micelle on gold nanorods prepared by seed mediated method and GW627368X was loaded on to the reduction responsive gold nanorod embedded micelle. Photothermal therapy was administered using cwNIR laser (808nm; 4W/cm2). Efficacy of nanoformulated GW627368X, photothermal therapy and combination of both were evaluated in vitro and in vivo. RESULTS In response to photothermal treatment, cells undergo regulated, patterned cell death by necroptosis. Combining GW627368X with photothermal treatment using single nanoparticle enhanced therapeutic outcome. In addition, these nanoparticles are effective X-ray CT contrast agents, thus, can help in monitoring treatment. CONCLUSION Reduction responsive nanorod embedded micelle containing folic acid and lipoic acid when treated on cervical cancer cells or tumour bearing mice, aggregate in and around cancer cells. Due to high glutathione concentration, micelles degrade releasing drug which binds surface receptors inducing apoptosis. When incident with 808nm cwNIR lasers, gold nanorods bring about photothermal effect leading to hyperthermic cell death by necroptosis. Combination of the two modalities enhances therapeutic efficacy by inducing both forms of cell death. GENERAL SIGNIFICANCE Our proposed treatment strategy achieves photothermal therapy and targeted drug delivery simultaneously. It can prove useful in overcoming general toxicities associated with chemotherapeutics and intrinsic/acquired resistance to chemo and radiotherapy.

Insights into molecular therapy of glioma: current challenges and next generation blueprint

Glioma accounts for the majority of human brain tumors. With prevailing treatment regimens, the patients have poor survival rates. In spite of current development in mainstream glioma therapy, a cure for glioma appears to be out of reach. The infiltrative nature of glioma and acquired resistance substancially restrict the therapeutic options. Better elucidation of the complicated pathobiology of glioma and proteogenomic characterization might eventually open novel avenues for the design of more sophisticated and effective combination regimens. This could be accomplished by individually tailoring progressive neuroimaging techniques, terminating DNA synthesis with prodrug-activating genes, silencing gliomagenesis genes (gene therapy), targeting miRNA oncogenic activity (miRNA-mRNA interaction), combining Hedgehog-Gli/Akt inhibitors with stem cell therapy, employing tumor lysates as antigen sources for efficient depletion of tumor-specific cancer stem cells by cytotoxic T lymphocytes (dendritic cell vaccination), adoptive transfer of chimeric antigen receptor-modified T cells, and combining immune checkpoint inhibitors with conventional therapeutic modalities. Thus, the present review captures the latest trends associated with the molecular mechanisms involved in glial tumorigenesis as well as the limitations of surgery, radiation and chemotherapy. In this article we also critically discuss the next generation molecular therapeutic strategies and their mechanisms for the successful treatment of glioma.

S100A7 has an oncogenic role in oral squamous cell carcinoma by activating p38/MAPK and RAB2A signaling pathway

Oral cancer consists of squamous cell carcinoma within the oral cavity or on the lip. The clinical prognosis of this cancer is mostly poor owing to delayed diagnosis and a lack of appropriate early detection biomarkers to identify the disease. In the current study, we investigated the role of the S100A7 calcium-binding protein in oral squamous cell carcinoma as an activator of the p38/MAPK and RAB2A signaling pathway. The aim of the present study was to determine whether S100A7 and RAB2A have a role in tumor progression and to assess their potential as early detection biomarkers for oral cancer. This study elucidated the functional and molecular mechanisms of S100A7 and RAB2A activity in oral cancer, leading us to conclude that S100A7 is the major contributing factor in the occurrence of oral cancer and promotes local tumor progression by activating the MAPK signaling pathway via the RAB2A pathway. We hypothesize that S100A7 affects cell motility and invasion by regulating the RAB2A-associated MAPK signaling cascades. Also, the downregulation of S100A7 expression by RNA interference-mediated silencing inhibits oral cancer cell growth, migration and invasion.

Glioma progression through the prism of heat shock protein mediated extracellular matrix remodeling and epithelial to mesenchymal transition

ABSTRACT Glial tumor is one of the intrinsic brain tumors with high migratory and infiltrative potential. This essentially contributes to the overall poor prognosis by circumvention of conventional treatment regimen in glioma. The underlying mechanism in gliomagenesis is bestowed by two processes‐ Extracellular matrix (ECM) Remodeling and Epithelial to mesenchymal transition (EMT). Heat Shock Family of proteins (HSPs), commonly known as “molecular chaperons” are documented to be upregulated in glioma. A positive correlation also exists between elevated expression of HSPs and invasive capacity of glial tumor. HSPs overexpression leads to mutational changes in glioma, which ultimately drive cells towards EMT, ECM modification, malignancy and invasion. Differential expression of HSPs – a factor providing cytoprotection to glioma cells, also contributes towards its radioresistance /chemoresistance. Various evidences also display upregulation of EMT and ECM markers by various heat shock inducing proteins e.g. HSF‐1. The aim of this review is to study in detail the role of HSPs in EMT and ECM leading to radioresistance/chemoresistance of glioma cells. The existing treatment regimen for glioma could be enhanced by targeting HSPs through immunotherapy, miRNA and exosome mediated strategies. This could be envisaged by better understanding of molecular mechanisms underlying glial tumorigenesis in relation to EMT and ECM remodeling under HSPs influence. Our review might showcase fresh potential for the development of next generation therapeutics for effective glioma management. HIGHLIGHTSHSPs activate glioma progression signaling leading to ECM remodulation and EMT.HSPs mediated modulation of glioma signaling pathways confer chemo/radio resistance.Novel strategies (HSP‐vaccines, inhibitors + anti‐glioma drugs, exosomes, miRNA) may aid in efficient glioma management.Detailed networking of HSPs in ECM remodeling and EMT in gliomagenesis and novel strategies targeting HSPs has been studied here.

Cooperative effect of BI-69A11 and celecoxib enhances radiosensitization by modulating DNA damage repair in colon carcinoma

Amplification of PI3K-Akt pathway promotes radioresistance in various cancers including colorectal carcinoma. Local recurrence in colon cancer causes poor prognosis affecting overall survival of cancer-affected patient population. To avoid local recurrence, pre-operative or post-operative additional radiotherapy is given. However, main concern regarding radiotherapy is to increase the radiosensitivity of malignant cell without hampering the activities of normal cells. In this context, addition of two or more than two chemotherapeutic drugs as a radiosensitizer is a common practice in radiation biology. BI-69A11 earlier showed potential apoptosis-inducing effect in melanoma and colon carcinoma. Celecoxib showed anti-cancer effects in both COX-2 dependent and independent pathways and used to act as a radiosensitizing enhancer. Here, we suggest that the combination of BI-69A11 and celecoxib inhibits the phosphorylation of ataxia telangiectasia mutated (ATM) kinase and DNA-PK responsible for ionizing radiation (IR)-induced double-strand break (DSB) repair. Moreover, the combinatorial effect of BI-69A11 and celecoxib attenuates the IR-induced G2/M cell cycle arrest. Furthermore, this combination also impairs IR-induced activation of Akt and downstream targets of ATM. This might lead to induced activation of apoptotic pathway after triple therapy treatment modulating pro-apoptotic and anti-apoptotic proteins. This activation of apoptotic pathway also showed the interdependence of PUMA and BAD in triple combination-treated colon cancer cells in a p53 independent manner. This study reveals the therapeutic potential of the triple combination therapy in prevention of radioresistance. Besides, it also demonstrates the cytotoxic effects of triple combination therapy in colon cancer. This study shows utility and potential implication on safety of the patients undergoing radiation therapy.

Therapeutic implication of ‘Iturin A’ for targeting MD-2/TLR4 complex to overcome angiogenesis and invasion

Tumor angiogenesis and invasion are deregulated biological processes that drive multistage transformation of tumors from a benign to a life-threatening malignant state activating multiple signaling pathways including MD-2/TLR4/NF-κB. Development of potential inhibitors of this signaling is emerging area for discovery of novel cancer therapeutics. In the current investigation, we identified Iturin A (A lipopeptide molecule from Bacillus megaterium) as a potent inhibitor of angiogenesis and cancer invasion by various in vitro and in vivo methods. Iturin A was found to suppress VEGF, a powerful inducer of angiogenesis and key player in tumor invasion, as confirmed by ELISA, western blot and real time PCR. Iturin A inhibited endothelial tube arrangement, blood capillary formation, endothelial sprouting and vascular growth inside the matrigel. In addition, Iturin A inhibited MMP-2/9 expression in MDA-MB-231 and HUVEC cells. Cancer invasion, migration and colony forming ability were significantly hampered by Iturin A. Expressions of MD-2/TLR4 and its downstream MyD88, IKK-α and NF-κB were also reduced in treated MDA-MB-231 and HUVEC cells. Western blot and immunofluorescence study showed that nuclear accumulation of NF-κB was hampered by Iturin A. MD-2 siRNA or plasmid further confirmed the efficacy of Iturin A by suppressing MD-2/TLR4 signaling pathway. The in silico docking study showed that the Iturin A interacted well with the MD-2 in MD-2/TLR4 receptor complex. Conclusively, inhibition of MD-2/TLR4 complex with Iturin A offered strategic advancement in cancer therapy.

Three Arm, Biotin‐tagged Carbazole‐Dicyanovinyl‐Chlorambucil Conjugate: Simultaneous Tumor Targetting, Sensing and Photoresponsive Anticancer Drug Delivery

The design, synthesis, and in vitro biological studies of a biotin-carbazole-dicyanovinyl-chlorambucil conjugate (Bio-CBZ-DCV-CBL; 6) are reported. This conjugate (6) is a multifunctional single-molecule appliance composed of a thiol-sensor DCV functionality, a CBZ-derived phototrigger as well as fluorescent reporter, and CBL as the anticancer drug, and Bio as the cancer-targeting ligand. In conjugate 6, the DCV bond undergoes a thiol-ene click reaction at pH<7 with intracellular thiols, thereby shutting down internal charge transfer between the donor CBZ and acceptor DCV units, resulting in a change of the fluorescence color from green to blue, and thereby, sensing the tumor microenvironment. Subsequent photoirradiation results in release of the anticancer drug CBL in a controlled manner.

NIR fluorescent organic nanoparticles for photoinduced nitric oxide delivery with self monitoring and real time reporting abilities

Nitric oxide photodonor (NOD) conjugated perylene tetracarboxylate ester (TPT) based fluorescent organic TPT(NOD)4 nanoparticles (NPs) with aggregation induced NIR emission have shown photoinduced nitric oxide delivery along with a red to green emission transition. Time dependent imaging and dose dependent cytotoxicity studies of these NPs using U87MG cells demonstrate the self monitoring and real time reporting abilities and potential anticancer activity of the system, respectively.

Regulation of Extracellular Matrix Remodeling and Epithelial-Mesenchymal Transition by Matrix Metalloproteinases: Decisive Candidates in Tumor Progression

Tumor biology is intricate and multifaceted. The genetic and epigenetic alterations accelerate normal cells to transform into aggressive malignant phenotype. Molecular principles of invasion and metastasis are indeed indispensable for profound understanding of tumorigenesis. The seeding pioneer cells from growing tumor eventually discharge from the original clump of mutant cells, invading adjacent tissues and mobilizing to distant sites. This attribute of cancer cells reduces patient’s survival rate and prognosis. Inquisition of mechanistic approach for metastasis is bestowed by two processes—extracellular matrix (ECM) remodeling and epithelial-mesenchymal transition (EMT). Proteases pave the way for invaders by breaking down the ECM and releasing pro-invasive factors from cell surface and ECM. Indeed, highly conserved EMT program leads to dissemination of single tumor cells from primary tumors. The zinc-dependent matrix MMPs are the most important effectors in these processes and frequently overexpressed in most of the tumors. Besides proteolysis, by activating or deactivating several growth factors, MMPs affect tumor neoangiogenesis and proliferation. The tissue inhibitors of metalloproteinases (TIMPs) play a central role in complex regulation of MMPs. An apt equilibrium between TIMPs and MMPs is significant in cell invasion and metastasis. These concepts are encouraged for pursuing MMPs as a signature for predicting metastasis and also as therapeutic target. A comprehensive understanding regarding enzyme-substrate interactions and regulation and specific MMPs’ functionality in cancer addresses that MMP inhibitors (MMPIs) should be specific in terms of MMP or degrading definite substrates. The scientific and clinical drive for second-generation MMPIs through the development of pharmaceutical reagents and clinical trials determining the therapeutic benefit to cancer patients should be geared up.

Abstract 4105: Diosgenin and temozolamide: A potential combinatorial chemotherapy to overcome temozolamide resistance in glioblastoma multiforme

Introduction: Glioblastoma multiforme (GBM) accounts for the most aggressive form of tumor showing poor prognosis. Prevailing treatment modality includes chemotherapy with temozolomide (TMZ) concomitant with surgical resection and/or irradiation. However, it has been observed that a number of patients are developing resistance to TMZ owing to its high dosage regimen. The aim of this study is to examine the effects of diosgenin (DSG), a natural steroidal saponin obtained from fenugreek, in combination with TMZ in human GBM cells and TMZ resistant GBM cells. Methodology: The potential of combinatorial chemotherapy for overcoming TMZ resistance was evaluated through development of TMZ resistant GBM clones. These clones were generated by treatment of GBM cells with sub-lethal dose of TMZ over several cycles. Cellular effects were studied by viability assay, flow cytometry and wound healing assay on both single and combined drug treated GBM cells and TMZ resistant cells, respectively. The morphological study and cellular uptake in combined or individual drug treated cells was assessed by microscopy and immunofluorescence staining. The time dependant effect of drugs on invasive and migratory potential of GBM cells and TMZ resistant cells was analysed through zymography for matrix metalloproteinases (MMPs) activity and western blot for apoptotic proteins, epithelial and mesenchymal (EMT) markers, MMPs and VEGF expression. Further, the drug induced apoptosis was also assessed through chromatin condensation and DNA laddering assay. Results: Our investigation shows that co-administration of DSG and TMZ resulted in a substantial increase in GBM cell apoptosis and marked inhibition of cell growth in vitro. Anti-angiogenic and anti-invasive potential of DSG and TMZ were assessed through in vitro studies. At molecular level, DSG and TMZ synergistically lower XIAP expression and cleavage of intracellular death substrates such as PARP thereby shifting the balance from survival to apoptosis as indicated by the rise in the sub-G1 cell population. This combination also alters EMT markers, downregulates the expression of Bcl-xL, Bcl-2, Mcl1, MMPs and VEGF and induces expression of Bax, AIF, cytochrome C. Conclusion: The results suggested that DSG in combination with TMZ reduced the dose of TMZ, when administered singly, and also inhibited the migration and invasion of GBM and TMZ resistant cells. It induced apoptosis and altered the expression of EMT markers. These findings reveal a new therapeutic potential for overcoming TMZ resistance in GBM therapy. This novel modality may be a promising tool for GBM treatment. Citation Format: Y Rajesh, Angana Biswas, Subhayan Das, Mahitosh Mandal. Diosgenin and temozolamide: A potential combinatorial chemotherapy to overcome temozolamide resistance in glioblastoma multiforme [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4105. doi:10.1158/1538-7445.AM2017-4105