Piyush Trivedi

Advances in Chalcones with Anticancer Activities

Chalcones are naturally occurring compounds exhibiting broad spectrum biological activities including anticancer activity through multiple mechanisms. Literature on anticancer chalcones highlights the employment of three pronged strategies, namely; structural manipulation of both aryl rings, replacement of aryl rings with heteroaryl scaffolds, molecular hybridization through conjugation with other pharmacologically interesting scaffolds for enhancement of anticancer properties. Methoxy substitutions on both the aryl rings (A and B) of the chalcones, depending upon their positions in the aryl rings appear to influence anticancer and other activities. Similarly, heterocyclic rings either as ring A or B in chalcones, also influence the anticancer activity shown by this class of compounds. Hybrid chalcones formulated by chemically linking chalcones to other prominent anticancer scaffolds such as pyrrol[2,1-c][1,4]benzodiazepines, benzothiazoles, imidazolones have demonstrated synergistic or additive pharmacological activities. The successful application of these three pronged strategies for discovering novel anticancer agents based on chalcone scaffold has resulted in many novel and chemically diverse chalcones with potential therapeutic application for many types of cancer. This review summarizes the concerted efforts expended on the design and development of anticancer chalcones recorded in recent literature and also provides an overview of the patents published in this area between 2007 and 2014 (WO2013022951, WO201201745 & US2012029489).

Human CDC2-like kinase 1 (CLK1): a novel target for Alzheimer's disease.

The cdc2-like kinases (CLKs) are an evolutionarily conserved group of dual specificity kinases belonging to the CMGC (cyclin-dependent kinases (CDKs), mitogen-activated protein kinases (MAP kinases), glycogen synthase kinases (GSK) and CDK-like kinases). The CLK family consists of four isoforms namely CLK1, CLK2, CLK3 and CLK4. The human CLK1 encoded protein comprises 454 amino acids and the catalytic domain of CLK1 exhibits the typical protein kinase fold. CLK1 has been shown to autophosphorylate on serine, threonine and tyrosine residues and phosphorylate exogenous substrates on serine and threonine residues. CLK1 plays an important role in the regulation of RNA splicing through phosphorylation of members of the serine and arginine-rich (SR) family of splicing factors. CLK1 is involved in the pathophysiology of Alzheimers disease by phosphorylating the serine residue in SR proteins. Nuclear speckles of the nucleoplasm contain the stored form of SR proteins and are moderately responsible for the choice of splicing sites during pre-mRNA splicing. Hence, the inhibition of CLK1 can be used as a therapeutic strategy for Alzheimers disease. Many natural and synthetic molecules are reported to possess CLK1 inhibitory activity. Some specific examples are Marine alkaloid Leucettamine B and KH-CB19. Leucettamine B is a potent inhibitor of CLK1 (15 nM), Dyrk1A (40 nM), and Dyrk2 (35 nM) and a moderate inhibitor of CLK3 (4.5 µM) whereas KH-CB19 is a highly specific and potent inhibitor of the CLK1/CLK4. X-ray crystallographic studies have revealed the binding mode of marine sponge metabolite hymenialdisine and a dichloroindolyl enamino nitrile (KH-CB19) to CLK1. This review focuses on the role of CLKs in the pathophysiology of Alzheimers disease and therapeutic potential of targeting CLK1 in Alzheimers disease drug discovery and development. In addition, the recent developments in drug discovery efforts targeting human CLK1 are also highlighted.

Synthesis, Cytotoxic Evaluation and In Silico Pharmacokinetic Prediction of Some Benzo[a]Phenazine-5-sulfonic acid Derivatives

Cancer is one of the life threatening diseases and the development of novel anticancer molecules is limited by many reasons. In the present investigation, some novel benzo[a]phenazine-5-sulfonic acid derivatives as DNA intercalator was designed with optimized pharmacokinetic features for cancer treatment. The compounds with desired pharmacokinetic profile were synthesized and structurally characterized. Cytotoxic activity study against HL-60 tumor cell lines shows that 10-dimethyl carboxamido derivative of benzo[a]phenazine-5-sulfonic acid is found to be the most active in the series with cytotoxic activity (IC(50) = 19 microM) comparable to cisplatin (IC(50) = 7 microM). The study concluded that the novel benzo[a]phenazine-5-sulfonic acid derivatives were found to have enhanced DNA binding affinity and exhibited significant activity in vitro against HL-60 cell lines. This work will also guide for further development of effective DNA intercalators for cancer treatment.

Synthesis and evaluation of biodegradable PCL/PEG nanoparticles for neuroendocrine tumor targeted delivery of somatostatin analog

Purpose: Neuroendocrine tumors often present a diagnostic and therapeutic challenge. We have aimed to synthesize and develop biodegradable nanoparticles of somatostatin analogue, octreotide for targeted therapy of human neuroendocrine pancreatic tumor. Methods: Direct solid phase peptide synthesis of octreotide was done. Octreotide loaded PCL/PEG nanoparticles were prepared by solvent evaporation method and characterized for transmission electron microscopy, differential scanning calorimetery (DSC), Zeta potential measurement studies. The nanoparticles were evaluated in vitro for release studies and peptide content. For biological evaluations, receptor binding & cytotoxicity studies were done on BON-1 neuroendocrine tumor cell line. Biodistribution of radiolabeled peptide and nanoparticles, tumor regression studies were performed on tumor-bearing mouse models. Results: We have synthesized and purified octreotide with the purity of 99.96% in our laboratory. PEG/PCL nanoparticles with an average diameter of 130–195 nm having peptide loading efficiency of 66–84% with a negative surface charge were obtained with the formulation procedure. Octreotide nanoparticles have a negative action on the proliferation of BON-1 cells. In vivo biodistribution studies exhibited major accumulation of octreotide nanoparticles in tumor as compared to plain octreotide. Octreotide nanoparticles inhibited tumor growth more efficiently than free octreotide. Conclusions: Thus, it was concluded that the PCL/PEG nanoformulation of octreotide showed high tumor uptake due to the enhanced permeation and retention (EPR) effect and then peptide ligand imparts targetability to the sst2 receptor and there by showing increase tumor growth inhibition. Selective entry of nanoparticles to the tumor also give the reduce side effects both in vivo and in vitro.

Synthesis of some coumarinyl chalcones and their antiproliferative activity against breast cancer cell lines

A series of coumarinyl chalcones derivatives were synthesized and evaluated for their antiproliferative activities on three different breast cancer cell lines (MDA-MB231, MDA-MB468, MCF7) and one non-cancer breast epithelial cell line (184B5). The coumarinyl derivatives exhibited anticancer activity against breast cancer cell lines at a micromolar range. A structure-activity relationship (SAR) analysis was performed by studying the effect of substituents on their antiproliferative activities. One of the compound 3i bearing methoxy substitutions at the R1, R2 and R3 positions of the phenyl ring showed comparable potency to the reference drug cisplatin as well as a two-fold higher selectivity for the breast cancer cell lines than 184B5 cells.

IND-2, a pyrimido[1″,2″:1,5]pyrazolo[3,4-b]quinoline derivative, circumvents multi-drug resistance and causes apoptosis in colon cancer cells.

Naturally occurring condensed quinolines have anticancer properties. In efforts to find active analogues, we designed and synthesized eight polycyclic heterocycles with a pyrimido[1″,2″:1,5]pyrazolo[3,4-b]quinoline framework (IND series). The compounds were evaluated for activity against colon (HCT-116 and S1-MI-80), prostate (PC3 and DU-145), breast (MCF-7 and MDAMB-231), ovarian (ov2008 and A2780), and hepatocellular (HepG2) cancer cells and against non-cancerous Madin Darby canine kidney (MDCK), mouse embryonic fibroblast (NIH/3T3), and human embryonic kidney cells (HEK293). IND-2, a 4-chloro-2-methyl pyrimido[1″,2″:1,5]pyrazolo[3,4-b]quinoline, exhibited more than ten-fold selectivity and potent cytotoxic activity against colon cancer cells relative to the other cancer and non-cancer cells. With five additional colon cancer cell lines (HT-29, HCT-15, LS-180, LS-174, and LoVo), IND-2 had similar cytotoxicity and selectivity, and sub-micromolar concentrations caused changes in the morphology of HCT-116 and HCT-15 cells. IND-2 did not activate the transactivating function of the pregnane X receptor (PXR), indicating that it does not induce PXR-regulated ABCB1 or ABCG2 transporters. Indeed, IND-2 was not a substrate of ABCB1 or ABCG2, and it induced cytotoxicity in HEK293 cells overexpressing ABCB1 or ABCG2 to the same extent as in normal HEK293 cells. IND-2 was cytotoxic to resistant colon carcinoma S1-MI-80 cells, approximately three- and five-fold more than SN-38 and topotecan, respectively. In HCT-116 colon cancer cells, IND-2 produced concentration-dependent changes in mitochondrial membrane potential, leading to apoptosis, and sub-micromolar concentrations caused chromosomal DNA fragmentation. These findings suggest that, by increasing apoptosis, IND-2 has potential therapeutic efficacy for colorectal cancer.

3D QSAR of aminophenyl benzamide derivatives as histone deacetylase inhibitors.

The article describes the development of a robust pharmacophore model and the investigation of structure activity relationship analysis of 48 aminophenyl benzamide derivatives reported for Histone Deacetylase (HDAC) inhibition using PHASE module of Schrodinger software. A five point pharmacophore model consisting of two aromatic rings (R), two hydrogen bond donors (D) and one hydrogen bond acceptor (A) with discrete geometries as pharmacophoric features was developed and the generated pharmacophore model was used to derive a predictive atom-based 3D QSAR model for the studied dataset. The obtained 3D QSAR model has an excellent correlation coefficient value (r(2)=0.99) along with good statistical significance as shown by high Fisher ratio (F=631.80). The model also exhibits good predictive power confirmed by the high value of cross validated correlation coefficient (q(2) = 0.85). The QSAR model suggests that hydrophobic character is crucial for the HDAC inhibitory activity exhibited by these compounds and inclusion of hydrophobic substituents will enhance the HDAC inhibition. In addition to the hydrophobic character, hydrogen bond donating groups positively contributes to the HDAC inhibition whereas electron withdrawing groups has a negative influence in HDAC inhibitory potency. The findings of the QSAR study provide a set of guidelines for designing compounds with better HDAC inhibitory potency.

Novel dietary lipid-based self-nanoemulsifying drug delivery systems of paclitaxel with p-gp inhibitor: implications on cytotoxicity and biopharmaceutical performance

Objectives: This work describes the development and characterization of novel self-nanoemulsifying drug delivery systems (SNEDDS) employing polyunsaturated fatty acids for enhancing the oral bioavailability and anticancer activity of paclitaxel (PTX) by coadministration with curcumin (Cu). Methods: Preformulation studies endorsed sesame oil, labrasol, and sodium deoxycholate as lipid surfactants and cosurfactants based on their solubility for the drugs and spontaneity of emulsification to produce nanoemulsions. Further, phase titration studies were performed to identify a suitable nanoemulsion region for preparing the SNEDDS formulation. Results: The prepared formulations were characterized through in vitro, in situ, and in vivo studies to evaluate the biopharmaceutical performance. In vitro drug release studies showed 2.8- to 3.4-fold enhancement in the dissolution rate of both drugs from SNEDDS as compared with the pure drug suspension. Cell line studies revealed 1.5- to 2.7-fold reduction in the cytotoxicity on MCF-7 cells by plain PTX-SNEDDS and PTX-Cu-SNEDDS vis-à-vis the PTX-suspension. In situ intestinal perfusion studies revealed significant augmentation in permeability and absorption parameters of drug from PTX-Cu-SNEDDS over the plain PTX-SNEDDS and PTX-suspension (p < 0.001). In vivo pharmacokinetic studies also showed a remarkable improvement (i.e., 5.8- to 6.3-fold) in the oral bioavailability (Cmax and AUC) of the drug from PTX-SNEDDS and PTX-Cu-SNEDDS vis-à-vis the PTX-suspension. Conclusions: Overall, the studies corroborated superior biopharmaceutical performance of PTX-Cu-SNEDDS.

Reduction in cisplatin genotoxicity (micronucleus formation) in non target cells of mice by protransfersome gel formulation used for management of cutaneous squamous cell carcinoma

Reduction in cisplatin genotoxicity (micronucleus formation) in non target cells of mice by protransfersome gel formulation used for management of cutaneous squamous cell carcinoma Cisplatin-loaded protransfersome system was prepared and characterized for in vitro drug permeation, drug deposition and antitumor effect. A histopathological study and a genotoxicity study were also done. The skin permeation data of cisplatin from protransfersome gel formulation revealed 494.33 ± 11.87 μg cm-2, which was significantly higher than that from the control plain drug solution in 0.9 % NaCl (p < 0.001). Untreated group of animals showed invasive moderately differentiated keratinizing squamous cell carcinoma (malignant stage). However, with cisplatin loaded protransfersome gel system simple epithelial hyperplasia (pre-cancerous stage) with no cancerous growth was observed. Also, a significant induction in micronucleus formation was found in the group that was treated with injectable intraperitoneal cisplatin preparation in 0.9 % saline as compared to the group treated with topical protransfersome gel formulation. The findings of this research work appear to support improved, site-specific and localized drug action in the skin, thus providing a better option for dealing with skin related problems like squamous cell carcinoma. Smanjenje genotoksičnosti cisplatina (stvaranje stanica s mikronukleusom) u neciljnim stanicama miša upotrebom gela s protransfersomima u terapiji karcinoma skvamoznih stanica kože U radu je opisana priprema protransfersoma s cisplatinom te njihova evaluacija: permeacija lijeka in vitro, odlaganje ljekovite tvari, histopatološke studije, antitumorski učinak i genotoksično djelovanje. Permeacija kroz kožu iz protransfersoma bila je 494,33 ± 11,87 μg cm-2, što je značajno više nego iz otopine lijeka u 0,9 % otopini NaCl (p < 0,001). Uz terapiju protransfersomima pojavila se obična hiperplazija epitela (prekancerozno stanje), dok su se u skupini netretiranih životinja pojavile invazivne, umjereno diferencirane skvamozne stanice karcinoma (maligno stanje). Osim toga, stvaranje stanica s malim jezgrama u skupini životinja koje su tretirane intraperitonealnim injekcijama cisplatina u fiziološkoj otopini bilo je značajnije u odnosu na skupinu koja je tretirana s topičkom formulacijom protransfersoma. Rezultati rada pokazuju da je formulacijom s protransfersomima postignuto poboljšano, specifično i lokalizirano djelovanje u koži, što pruža mogućnost boljeg rješavanja problema kao što je karcinom skvamoznih stanica.

Design, synthesis, cytotoxic evaluation, and QSAR study of some 6H-indolo[2,3-b]quinoxaline derivatives

In the pathway of anticancer drug development, we designed and synthesized some 6H-indolo[2,3-b]quinoxaline derivatives (which act as DNA intercalators) by structural modification. The structure of the 6H-indolo[2,3-b]quinoxaline derivatives was confirmed by IR, NMR, Mass and elemental analysis. The compounds (IDQ-5, IDQ-10, IDQ-11, IDQ-13, and IDQ-14) exhibited significant in vitro activity against a human leukemia (HL-60) cell line. The QSAR derived for modeling the cytotoxic activity of 6H-indolo[2,3-b]quinoxaline derivatives suggests that candidate structures for increased cytotoxic potency should incorporate cyclic substituents or substituents with primary carbon atoms.