Development of Novel Therapeutic Strategies for Pancreatic Cancer Treatment

Pancreatic cancer (PanCa) is the third deadliest cancer in the USA due to the late diagnosis and development of chemo-resistance, with a 5-year survival rate of less than 10%. The prognosis of patients with pancreatic ductal adenocarcinoma is extremely poor, and current therapies such as Gemcitabine, 5-FU, Nab-paclitaxel and, FOLFIRINOX alone or in combination, have displayed improved but marginal survival rates for patients. Therefore, research efforts are underway to discover new therapeutic options to treat PanCa and overcome resistance to available therapies. Mucin, MUC13 is transmembrane glycoprotein, which is aberrantly overexpressed in PanCa and promoting cancer growth. Structural domains of MUC13, lead to oncogenic characteristics during cancer progression. Our lab previously established the role of MUC13 in tumor progression and metastasis by alteration of signaling pathways. Recent observations suggest the role of MUC13 in drug resistance and apoptosis in several cancer types. Therefore, it is of great interest to explore the role of MUC13 in chemoresistance in PanCa. Unlike other cancer types, PanCa is highly resistant to tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) that emerges as one of the most-promising cancer therapeutic drugs. It is a death ligand that can selectively induce apoptosis in cancer cells over normal cells. Our recent work has demonstrated that MUC13 expressing cells showed resistance to TRAIL induced cell death and MUC13 knockdown leads to TRAIL sensitivity in cells. We have also observed that MUC13 expression blocks the activation of caspase-8 and Bid in PanCa cells in response to TRAIL treatment. Further investigation showed that alpha and beta domains of MUC13 are indispensable for blocking caspase-8 activation and PARP cleavage, indicating that the MUC13 blocks TRAIL-induced signaling upstream to Bid by inhibiting caspase-8 activation. Current studies revealed a new role of MUC13 ininhibiting TRAIL mediated activation of extrinsic apoptotic pathway in pancreatic cancer. MicroRNAs (miRNA) have been identified as attractive targets for therapeutic intervention. The functional significance of lost miRNAs have been reported in several human malignancies, including PanCa. Restitution of lost miRNA function can provide a potential therapeutic benefit. Prior work has identified microRNA-145 (miR-145) as a tumor suppressor miRNA in PanCa. The restoration of miR-145 downregulates a number of oncogenes including mucin MUC13 and efficiently inhibits tumor growth in mice. Inhibition of MUC13 using miR-145 restoration resulted in TRAIL mediated increase in apoptotic cell death as evidenced by sub-G0 population and inhibition of MUC13, activation of caspase 8 and, cleavage of PARP-1. MiR-145 replacement can sensitize TRAIL therapy and counteract chemoresistance mechanism in PanCa. The main challenge for successful translation of miRNAs into clinical practice remains an effective in vivo delivery system. Hence, the focus of this study was to develop and assess the efficacy of a miR-145 based nanoparticle formulation for PanCa treatment. Magnetic nanoparticle (MNP) based nanoformulation of miR-145 (miR-145-MNPF) was developed for the intracellular delivery and sustained release of miR-145. The positively charged polyethyleneimine molecules were used to increase the loading efficiency of miR-145. Treatment of cells with miR-145-MNPF led to efficient intracellular delivery of miR-145 mimics as observed through Prussian blue staining. This led to the simultaneous upregulation of miR-145 levels in cells which resulted in significant downregulation of target oncogenes including MUC13, HER2, pAKT and p53. miR-145-MNPF efficiently restores miR-145 in PanCa cells and inhibits growth and invasion of PanCa. miR-145 restitution using miR-145-MNPF may offer a potential therapeutic strategy for pancreatic cancer. As discussed earlier that miR-145 restoration sensitized the TRAIL therapy in PanCa cells. Herein, we demonstrate the integration of novel delivery approach to reduce the delivery challenge of TRAIL. We have engineered unique superparamagnetic nanoparticles (MNPs) for co-delivering miR-145 and plasmid TRAIL for improving TRAIL response in PanCa model. MNP-miR-145-TRAIL nanoparticles were codelivered miR-145 and TRAIL to PanCa cells, which resulted in simultaneous restoration of miR-145 and inhibition of acquired resistance to TRAIL. The current study demonstrates that acquired resistance to TRAIL in PanCa cells can be minimized with the replenishment of miR-145 expression. Combined actions of miR-145 and TRAIL markedly improve TRAIL-induced apoptotic effects in PanCa cells through the activation of an extrinsic apoptosis pathway as indicated by activation of DR4, FLIP, FADD and enhanced expression of cleaved caspase-8. The co-delivery of miR-145 and TRAIL using MNP nanoparticles inhibited tumorigenic characteristics of PanCa cells. The results were reciprocated and were further confirmed with the inhibition of tumorsphere formation and in vivo tumorigenicity in xenograft mice. Immunohistochemical staining of excised tumor tissues demonstrates an activation of the death receptor pathway and subsequent expression of apoptotic markers. Pancreatic tumor microenvironment is a complex dynamic space which leads to desmoplasia and involved in metastasis and impediments against intracellular drug delivery. Despite extensive research efforts, there is not considerable progress in cancer therapeutics due to genomic complexity and heterogenicity of pancreatic cancer. Modern tumor therapy must be patient specific and customized for individual patients. It should be tailored for a patient-based response to the specific treatment. Thus, novel delivery vehicles are required that are biocompatible and non-immunogenic. This is possible by utilizing an autologous biological material as delivery vehicles that can be applied as a personalized medicine. Towards this, our lab has optimized an exosome based therapeutic approach, which utilizes exosomes isolated from the cultured tumor adjacent normal (NAT) fibroblast cells. We utilized this scaffold for safe and effective delivery of therapeutic payload. Our results demonstrated that NAT derived exosomal formulation (Exo-ORM) significantly enhanced the efficacy of ormeloxifene to inhibit stroma as indicated by decreased expression of α-SMA, desmin and hyaluronic acid. Exo-ORM formulation effectively inhibit EMT/SHH signaling in PanCa cells and in vivo models. NAT derived exosomes will be a promising therapeutic carrier with preferential size for passive targeting, proficient biophysical characteristics, biocompatible and nonimmunogenic vehicle for PanCa therapy

Short Fibre and Particulate-reinforced Rubber Composites

Particulate fillers (carbon black and silica) and short fibre (aromatic polyamide, Kevlar have been utilised to produce rubber composites based on acrylonitrile-co-butadiene rubber (NBR). Mechanical properties of these composites have been determined and compared with unfilled rubber vulcanisate. The effect of surface treatment on the improvement of strength, in case of Kevlar, has also been considered. The influence of elevated temperature on tear strength, an important failure criterion, has been evaluated. Scanning electron microscopy has been used as a tool to correlate the topographical features associated with changes in the tear strength of the composites

A Brief Overview on Ferrite (Fe3O4) Based Polymeric Nanocomposites: Recent Developments and Challenges

In this article, we have mainly discussed about ferrite (Fe3O4) and its polymer based nanocomposites. Ferrite particles have become an important research material because of their vast applications in the field of biotechnology, magnetic resonance imaging (MRI), and data storage. It has been observed that ferrite Fe3O4 particles show best performance for size less than 10-30 nm. This happens due to the super paramagnetic nature of such particles. In super paramagnetic range these particles exhibit zero remanence or coercivity. Therefore, various properties of ferrite (Fe3O4) nanoparticles and its polymer nanocomposites are very much dependent on the size, and distribution of the particles in the polymeric matrix. Moreover, it has been also observed that the shape of the nanocrystals plays important role in the determination of their fundamental properties. These particles show instability over longer times due to the formation of agglomerates generated by high surface energies. Therefore, protection strategies such as grafting and coatings with silica/carbon or polymers have been developed to stabilize them chemically. Recently, silylation technique is mainly used for the modification of nanoparticles. Experimentally, it has been observed that nanocomposites composed of polymer matrices and ferrite showed substantial improvements in stiffness, fracture toughness, sensing ability (magnetic as well as electric), impact energy absorption, and electro-catalytic activities to bio-species

Lignin Reinforced Rubber Composites

Lignin is the country's second most abundant renewable biomass resource next to cellulose. The pulp and paper industries produce very large quantities of lignin, most of those are burned to recover energy, pulping chemicals, enzymatic or acid hydrolysis to sugars followed by fermentation to alcohols. Another emerging technology where the lignin being used is in the adhesives and asphalts. For the former, lignin partly replaces phenol in phenol-formaldehyde formulations, for the latter lignin is used as an extender. Lignin in polyurethanes is for good mechanical properties and reactions of lignin such as grafting and crosslinking agent are also well known. Novolak-hexamine based phenolic resins are commonly used as reinforcing and processing aids in nitrile rubber (NBR) compounds. Not only the oil and petrol resistances increase significantly , resin loading is also found to offer better heat resistant properties than carbon blacks. For seals, valves and gasket applications addition of phenolic resins provides superior abrasion resistance, ageing and negligible hardening effects at elevated temperatures. Poor tackiness of NBR compounds can easily be eliminated by using phenolic resin in place of carbon black. The study presented here is to explore the possibility of employing lignin into some value -added rubber based composites . Lignin, gymnosperms, angiosperms and glass varieties, contain alcohol and phenolic groups and also double bonds in their structural moiety and therefore, could resinify into prepolymer in presence of hexamine.Varied proportions of lignin upto 50 parts with respect to total rubber plus hexamine,have been incorporated in medium acrylonitrile (37%) NBR and studied for their processing characteristics and physico-mechanical properties e.g. reinforcement, oil and fuel resistances, ageing and thermal stability. Efficacy of lignin has been found to be superior to either phenolic resin-hexamine or carbon black filled compounds. Finally, attempt has also been made to modify the surface chemistry incorporating CO,> C=O etc. groups by additions of dicumyl peroxide and this modified lignin was found to offer improved rubber-filler adhesion, tackiness and physical properties

Gemcitabine Combination Nano Therapies for Pancreatic Cancer

Pancreatic cancer is one of the deadliest causes of cancer-related death in the United States, with a 5-year overall survival rate of 6 to 8%. These statistics suggest that immediate medical attention is needed. Gemcitabine (GEM) is the gold standard first-line single chemotherapy agent for pancreatic cancer but, after a few months, cells develop chemoresistance. Multiple clinical and experimental investigations have demonstrated that a combination or co-administration of other drugs as chemotherapies with GEM lead to superior therapeutic benefits. However, such combination therapies often induce severe systemic toxicities. Thus, developing strategies to deliver a combination of chemotherapeutic agents more securely to patients is needed. Nanoparticle-mediated delivery can offer to load a cocktail of drugs, increase stability and availability, on-demand and tumor-specific delivery while minimizing chemotherapy-associated adverse effects. This review discusses the available drugs being co-administered with GEM and the limitations associated during the process of co-administration. This review also helps in providing knowledge of the significant number of delivery platforms being used to overcome problems related to gemcitabine-based co-delivery of other chemotherapeutic drugs, thereby focusing on how nanocarriers have been fabricated, considering the modes of action, targeting receptors, pharmacology of chemo drugs incorporated with GEM, and the differences in the physiological environment where the targeting is to be done. This review also documents the focus on novel mucin-targeted nanotechnology which is under development for pancreatic cancer therapy

Butyl Rubber-Nylon Composites with Improved Flame Retardancy & Gas Impermeability

Butyl rubber, because of its high packing density and chemical structure is inherently impermeable to air and gases. However, the elastomer is highly flammable owing to its neat carbon-hydrogen backbone structure. The particular rubber is extensively being used as coating materials for nylon, cotton, polyester etc., for development of clothing outfits for service personnel working in hazardous chemical environments . It is, therefore , essential to evolve flame retardant butyl rubber compositions which could make such clothings impermeable to chemical agents having adequate flame retardancy.The present paper describes an attempt towards using various chemical additives viz. brominated phenyl ethers, chlorinated paraffin, various inorganic oxides and halogenated elastomer, either singly or in combinations as potential flame retardants in bromo-butyl rubber compositions. The cements were then prepared by adding toluene to these compositions (20 to 30% solid content). The homogenised cements were then applied on both sides of nylon fabric with varying add -on concentrations in a laboratory coating machine with doctors blade specially designed for this purpose. The coated fabrics were cured at different temperatures in step curing between 70-150°C, tested for impermeability against hazardous warfare agents and found to offer enhanced protection against these chemicals . Standard test methods e.g. (a) exposure of the fabric to direct flame as per BS method 3119 (b) limited oxygen index as per ASTM specification D-2663 were followed in the evaluation of flame retardancy. The fabrics showed no after glow- low after flame (2.5 sec. against 6 sec. specified)and 7.2 cm char length against 12 cm max. permissible value. The hysicomechanical' properties e.g., breaking and tensile strengths were determined . Morphology and rubber fabric adhesion were studied using Scanning Electron Microscopy

Molecular-receptor-specific, non-toxic, near-infrared-emitting Au cluster-protein nanoconjugates for targeted cancer imaging

Molecular-receptor-targeted imaging of folate receptor positive oral carcinoma cells using folic-acid-conjugated fluorescent Au25 nanoclusters (Au NCs) is reported. Highly fluorescent Au25 clusters were synthesized by controlled reduction of Au+ ions, stabilized in bovine serum albumin (BSA), using a green-chemical reducing agent, ascorbic acid (vitamin-C). For targeted-imaging-based detection of cancer cells, the clusters were conjugated with folic acid (FA) through amide linkage with the BSA shell. The bioconjugated clusters show excellent stability over a wide range of pH from 4 to 14 and fluorescence efficiency of ~5.7% at pH 7.4 in phosphate buffer saline (PBS), indicating effective protection of nanoclusters by serum albumin during the bioconjugation reaction and cell-cluster interaction. The nanoclusters were characterized for their physico-chemical properties, toxicity and cancer targeting efficacy in vitro. X-ray photoelectron spectroscopy (XPS) suggests binding energies correlating to metal Au 4f7/2˜83.97 eV and Au 4f5/2~87.768 eV. Transmission electron microscopy and atomic force microscopy revealed the formation of individual nanoclusters of size ~1 nm and protein cluster aggregates of size ~8 nm. Photoluminescence studies show bright fluorescence with peak maximum at ~674 nm with the spectral profile covering the near-infrared (NIR) region, making it possible to image clusters at the 700-800 nm emission window where the tissue absorption of light is minimum. The cell viability and reactive oxygen toxicity studies indicate the non-toxic nature of the Au clusters up to relatively higher concentrations of 500 µg ml-1. Receptor-targeted cancer detection using Au clusters is demonstrated on FR+ve oral squamous cell carcinoma (KB) and breast adenocarcinoma cell MCF-7, where the FA-conjugated Au25 clusters were found internalized in significantly higher concentrations compared to the negative control cell lines. This study demonstrates the potential of using non-toxic fluorescent Au nanoclusters for the targeted imaging of cancer

Antibody-Drug Conjugates for Cancer Therapy: Chemistry to Clinical Implications

Chemotherapy is one of themajor therapeutic options for cancer treatment. Chemotherapy is often associated with a low therapeutic window due to its poor specificity towards tumor cells/tissues. Antibody-drug conjugate (ADC) technology may provide a potentially new therapeutic solution for cancer treatment. ADC technology uses an antibody-mediated delivery of cytotoxic drugs to the tumors in a targeted manner, while sparing normal cells. Such a targeted approach can improve the tumor-to-normal tissue selectivity and specificity in chemotherapy. Considering its importance in cancer treatment, we aim to review recent efforts for the design and development of ADCs. ADCs are mainly composed of an antibody, a cytotoxic payload, and a linker, which can offer selectivity against tumors, anti-cancer activity, and stability in systemic circulation. Therefore, we have reviewed recent updates and principal considerations behind ADC designs, which are not only based on the identification of target antigen, cytotoxic drug, and linker, but also on the drug-linker chemistry and conjugation site at the antibody. Our review focuses on site-specific conjugation methods for producing homogenous ADCs with constant drug-antibody ratio (DAR) in order to tackle several drawbacks that exists in conventional conjugation methods

Novel Paclitaxel Nanoformulation Impairs De Novo Lipid Synthesis in Pancreatic Cancer Cells and Enhances Gemcitabine Efficacy

Pancreatic cancer (PanCa) is a highly lethal disease with a poor 5 year survival rate, less than 7%. It has a dismal prognosis, and more than 50% of cases are detected at an advanced and metastatic stage. Gemcitabine (GEM) is a gold standard chemotherapy used for PanCa treatment. However, GEM-acquired resistance in cancer cells is considered as a major setback for its continued clinical implementation. This phenomenon is evidently linked to de novo lipid synthesis. PanCa cells rely on de novo lipid synthesis, which is a prime event in survival and one of the key drivers for tumorigenesis, cancer progression, and drug resistance. Thus, the depletion of lipogenesis or lipid metabolism can not only improve treatment outcomes but also overcome chemoresistance, which is an unmet clinical need. Toward this effort, our study reports a unique paclitaxel−poly(lactic-co-glycolic acid) (PLGA) nanoparticles (PPNPs) formulation which can target lipid metabolism and improve anticancer efficacy of GEM in PanCa cells. PPNPs inhibit excessive lipid formation and alter membrane stability with compromised membrane integrity, which was confirmed by Fourier transform infrared and zeta potential measurements. The effective interference of PPNPs in lipid metabolic signaling was determined by reduction in the expression of FASN, ACC, lipin, and Cox-2 proteins. This molecular action profoundly enhances efficacy of GEM as evident through enhanced inhibitory effects on the tumorigenic and metastasis assays in PanCa cells. These data clearly suggest that the ablation of lipid metabolism might offer an innovative approach for the improved therapeutic outcome in PanCa patients

MicroRNA-145 replacement as a therapeutic tool to Improve TRAIL therapy

Pancreatic cancer (PanCa) is a third leading cause of cancer related deaths in US. Unlike other cancers, PanCa is highly resistant to TNF-related apoptosis-inducing ligand (TRAIL) that emerges as one of the most-promising therapy in clinical trials. Our group has previously identified microRNA-145 (miR-145) is downregulated in PanCa, the restoration of which inhibits tumor growth and enhances gemcitabine sensitivity. In this study, we have observed that miR-145 restoration in PanCa cells renders them sensitive to TRAIL treatment. Therefore, we have engineered unique superparamagnetic nanoparticles (SPs) for co-delivering miR-145 and TRAIL in PanCa for improving their therapeutic response to TRAIL. The results in this study demonstrate that acquired resistance to TRAIL in PanCa cells can overcome with the replacement of lost levels of miR-145 expression. Our SP nanoparticles were engineered to co-deliver miR-145 and TRAIL to PanCa cells, which resulted in simultaneous restoration of miR-145 and inhibition of acquired resistance to TRAIL. Combined actions of miR-145 and TRAIL markedly improve TRAIL-induced apoptotic effects in PanCa cells through the activation of an extrinsic apoptosis pathway pathway as indicated by activation of DR5, FLIP, FADD and enhanced expression of caspase-8/3. The co-delivery of miR-145 and TRAIL using SP nanoparticles inhibited tumorigenic characteristics of PanCa cells, which include proliferation, invasion, migration and clonogenicity. The results were reciprocated and got further confirmed with the inhibition of tumorsphere formation and in vivo tumorigencity in xenograft mice. Immunohistochemical staining of excised tumor tissues demonstrate an activation of death receptor pathway and subsequent expression of apoptotic markers. The study provides novel insights on two facades- how resistance of cancer cells to TRAIL-based pro-apoptotic therapies can be tackled, and how efficient intracellular delivery of TRAIL can be achieved. Our results suggest that acquired resistance to TRAIL can be overcome by co-delivery of miR-145 and pEGFP-TRAIL using SP nanoparticles