Sudipta Basu

Novel self-assembled lithocholic acid nanoparticles for drug delivery in cancer

Novel versatile self-assembled nanoparticles were developed from biocompatible, biodegradable lithocholic acid derivatives. These nanoparticles can incorporate different cytotoxic drugs (paclitaxel and doxorubicin) and PI3K signalling inhibitor (PI103). Drugs were released from the nanoparticles in a slow, sustained manner at acidic pH. The drug loaded nanoparticles were internalized through lysosomal compartments and induced cell death in HeLa cervical cancer cells.

Biological Activity of Coumarin Derivatives as Anti-Leishmanial Agents

Cutaneous leishmaniasis affects nearly 0.7 to 1.3 million people annually. Treatment of this disease is difficult due to lack of appropriate medication and the growing problem of drug resistance. Natural compounds such as coumarins serve as complementary therapeutic agents in addition to the current treatment modalities. In this study, we have performed an in-silico screening of the coumarin derivatives and their anti-leishmanial properties has been explored both in-vitro and in-vivo. One of the compounds (compound 2) exhibited leishmanicidal activity and to further study its properties, nanoliposomal formulation of the compound was developed. Treatment of cutaneous lesions in BALB/c mice with compound 2 showed significantly reduced lesion size as compared to the untreated mice (p<0.05) suggesting that compound 2 may possess anti-leishmanial properties.

Loading of an anti-cancer drug into mesoporous silica nano-channels and its subsequent release to DNA

Mesoporous silica nano-channel (MCM-41) based molecular switching of a biologically important anticancer drug, namely, ellipticine (EPT) has been utilized to probe its efficient loading onto MCM-41, and its subsequent release to intra-cellular biomolecules, like DNA. By exploiting various spectroscopic techniques (like, steady state fluorescence, time-resolved fluorescence and circular dichroism), it has been shown that EPT can be easily translocated from MCM-41 to DNA without using any external stimulant. Blue emission of EPT in a polar aprotic solvent, i.e., dichloromethane (DCM), completely switches to green upon loading inside MCM-41 due to the conversion from a neutral to a protonated form of the drug inside nano-pores. Powder X-ray diffraction (PXRD), N2 gas adsorption and confocal fluorescence microscopy results confirm the adsorption of EPT inside the nano-pores of MCM-41. Here, the lysozyme (Lyz) protein has been utilized as a pore blocker of MCM-41 in order to prevent premature drug release. Interestingly, EPT is released to DNA even from the EPT-MCM-Lyz composite system, and results in intensification of green fluorescence. Electron microscopy results reveal the formation of a distinctive garland kind of morphology involving MCM-41 and DNA probably through non-covalent interactions, and this is believed to be responsible for the DNA assisted release of drug molecules from silica nano-pores. Confocal laser scanning microscopy (CLSM) imaging revealed that EPT-MCM is successfully internalized into the HeLa cervical cancer cells and localized into the nucleus. Cell viability assay results infer that EPT-MCM and EPT-MCM-Lyz showed much improved efficacy in HeLa cancer cells compared to free ellipticine.

Dual drug loaded vitamin D3 nanoparticle to target drug resistance in cancer

Overcoming drug resistance is one of the most challenging problems in cancer chemotherapy. Drug cocktails can overcome the drug resistance. However, multiple drug combinations lead to multifold increment of off-target toxicity, as well as the delivery of the required therapeutic amount of combined drugs remains problematic. To address these problems, we have developed a sub 200 nm vitamin D3 nanoparticle, which can contain a rational combination of dual drugs (PI103 and cisplatin or doxorubicin or proflavine). The size, shape and morphology of these dual drug containing vitamin D3 nanoparticles were characterized by DLS, FESEM, AFM and TEM. The nanoparticles released the dual drugs in high quantity at pH = 5.5 compared to pH = 7.4 in a slow and sustained manner over 72 h with stability over 15 days at 37 °C, as well as 4 °C. These dual drug loaded nanoparticles induced increased cell death in human hepatocellular carcinoma, Hep3B cells at 24 h compared to monotherapy; moreover, they were effective against cisplatin-resistant cells (Hep3B-R) as well. VitD3–PI103–CDDP-NP and vitD3–PI103–Dox-NP showed cytotoxicity by inducing apoptosis through DNA damage. Furthermore, vitD3–PI103–CDDP-NP showed considerably improved efficacy in 5-fluorouracil (5-FU) resistant Hep3B–5FU-R cells; its activity was even better compared to 5-FU. Finally, vitD3–PI103–proflavine-NP internalized into Hep3B-R cells considerably faster (within 3 minutes) compared to Hep3B cells, as visualized by fluorescent microscopy. Therefore, these dual drug loaded nanoparticles can successfully overcome the trauma of drug resistance and have the potential to be applied into the clinics for improved cancer therapeutics.

Synthesis, characterization and in vitro evaluation of novel vitamin D3 nanoparticles as a versatile platform for drug delivery in cancer therapy

Development of novel nanotechnology based platforms can impact cancer therapeutics in a paradigm shifting manner. The major concerns in drug delivery in cancer therapy are the biocompatibility, biodegradability, non-toxic nature, easy and short synthesis and versatility of the nanovectors. Herein we report the engineering of versatile nanoparticles from biocompatible, biodegradable and non-toxic lipid soluble vitamin D3. We have conjugated different clinically used cytotoxic drugs (paclitaxel and doxorubicin) as well as PI3 kinase inhibitor (PI103) with vitamin D3 using a succinic acid linker. Sub-200 nm, monodispersed nanoparticles with high drug loading were engineered from the vitamin D3-succinic acid-drug conjugates. These nanoparticles released the active drugs at pH 5.5 in a slow and sustained manner over 100 h. Furthermore, these nanoparticles were taken up by HeLa cells into the low pH lysosomal compartments through an endocytosis mechanism in 6 h. Finally, these drug loaded vitamin D3 nanoparticles induced HeLa cervical cancer cell death in a dose dependent manner at 48 h to show their potential in cancer therapeutics.

Hyaluronic acid cloaked oleic acid nanoparticles inhibit MAPK signaling with sub-cellular DNA damage in colon cancer cells

RAS-RAF-MEK-ERK cascade in mitogen activated protein kinase (MAPK) signaling has been hijacked in colon cancer. However, the selective targeting of MAPK signaling components in colon cancer cells has remained a surmountable challenge. To address this, we have engineered hyaluronic acid cloaked 154 nm diameter oleic acid nanoparticles (HA-OA-NPs) comprising both an ERK inhibitor (AZD6244) and a DNA damaging drug (cisplatin). Dual drugs were slowly released from the HA-OA-NPs at an acidic pH (pH = 5.5) over 72 h. HCT-116 colon cancer cells engulfed these HA-OA-NPs by a CD44 receptor and clathrin-dependent endocytosis pathways followed by an accumulation into lysosomes over 6 h. These HA-OA-NPs inhibited the phosphorylation of extracellular signal-regulated kinases (ERK1 and ERK2) and damaged sub-cellular DNA to induce remarkable colon cancer cell (HCT-116 and DLD-1) death in contrast to a free drug cocktail at 24 h post incubation. Due to the biocompatibility and biodegradability of the nanoparticle components, the HA-OA-NPs could be brought into clinics as a platform for the synchronized inhibition of multiple targets for improved therapeutic efficacy in colon cancer patients.

Impairing Powerhouse in Colon Cancer Cells by Hydrazide–Hydrazone-Based Small Molecule

Mitochondrion has emerged as one of the unconventional targets in next-generation cancer therapy. Hence, small molecules targeting mitochondria in cancer cells have immense potential in the next-generation anticancer therapeutics. In this report, we have synthesized a library of hydrazide–hydrazone-based small molecules and identified a novel compound that induces mitochondrial outer membrane permeabilization by inhibiting antiapoptotic B-cell CLL/lymphoma 2 (Bcl-2) family proteins followed by sequestration of proapoptotic cytochrome c. The new small molecule triggered programmed cell death (early and late apoptosis) through cell cycle arrest in the G2/M phase and caspase-9/3 cleavage in HCT-116 colon cancer cells, confirmed by an array of fluorescence confocal microscopy, cell sorting, and immunoblotting analysis. Furthermore, cell viability studies have verified that the small molecule rendered toxicity to a panel of colon cancer cells (HCT-116, DLD-1, and SW-620), keeping healthy L929 fibroblast cells unharmed. The novel small molecule has the potential to form a new understudied class of mitochondria targeting anticancer agent.