Sudeep Gupta

Design and Development of Integrase Inhibitors as Anti-HIV Agents

A review is presented on different categories of compounds that have been studied for the inhibition of the HIV-1 integrase to develop anti-HIV agents. These compounds are: oligonucleotides (double-stranded, triplex, and G-quartet), curcumin analogues, polyhydroxylated aromatic compounds, diketo acids, caffeoyl- and galloyl - based compounds, hydrazides and amides, tetracyclines, and depsides and depsidones. For all these compounds, the important structural features essential for the inhibition of the integrase are pointed out.

A Quantitative Structure-Activity Relationship Study on Some Matrix Metalloproteinase and Collagenase Inhibitors

A quantitative structure-activity relationship (QSAR) study is made on some hydroxamic acid-based inhibitors of matrix metalloproteinases (MMPs) and a bacterial collagenase, namely Clostridium histolyticum collagenase (ChC), that also belongs to an MMP family, M-31, using Kiers valence molecular connectivity index (1)chi(v) of the substituents and electrotopological state (E-state) indices of some atoms. The results indicate that out of the four MMPs (MMP-1, MMP-2, MMP-8, and MMP-9) studied, MMP-2 and MMP-9 can be structurally quite similar, but widely differing from MMP-1 and MMP-8 and ChC. For MMP-2 and MMP-9, the inhibition activity of compounds is shown to depend on both (1)chi(v )and E-state indices, while for MMP-1 and MMP-8 it is shown to depend only on E-state indices and for ChC only on (1)chi(v). However, in all the cases, an aromatic group like C(6)F(5) or 3-CF(3)-C(6)H(4) attached to SO(2) moiety in the compounds is indicated to be equally beneficial, due to probably the involvement of fluorine atom(s) in charge-charge interactions with the Zn(2+) ion of the enzymes or in the formation of the hydrogen bonds with some sites of the receptors.

A comparative QSAR study on carbonic anhydrase and matrix metalloproteinase inhibition by sulfonylated amino acid hydroxamates.

A quantitative structure-activity relationship (QSAR) study is made on the inhibition of a few isozymes of carbonic anhydrase (CA) and some matrix metalloproteinases (MMPs), both zinc containing families of enzymes, by sulfonylated amino acid hydroxamates. For both enzymes, the inhibition potency of the hydroxamates is found to be well correlated with Kiers first-order valence molecular connectivity index 1χv of the molecule and electrotopological state indices of some atoms. From the results, it is suggested that while hydroxamate-CA binding may involve mostly polar interactions, hydroxamate-MMP and hydroxamate-ChC (ChC: Clostridium histolyticum collagenase, another zinc enzyme related to MMPs) bindings may involve some hydrophobic interactions. Both MMPs and ChC also possess some electronic sites of exactly opposite nature to the corresponding sites in CAs. A group such as C 6 F 5 present in the sulfonyl moiety is shown to be advantageous in both CA and MMP (also ChC) inhibitions, which is supposed to be due to the interaction of this group with Zn 2+ ion present in the catalytic site of both families of enzymes.

A quantitative structure–activity relationship study of hydroxamate matrix metalloproteinase inhibitors derived from funtionalized 4-aminoprolines

A quantitative structure–activity relationship (QSAR) study has been made on the inhibitions of some matrix metalloproteinases (MMPs) by functionalized 4-aminoproline based hydroxamates. Attempts have been made to correlate the inhibition potencies of these hydroxamates with Kiers first-order valence molecular connectivity index (1χv) of substituents and electrotopological state (E-state) indices of some atoms. The correlations obtained for the inhibitions of all the enzymes studied, i.e. MMP-1, MMP-2, MMP-3, MMP-7, and MMP-13, were not so uniform, but suggested that in almost all the cases the substituents at the amide nitrogen may be conducive to the activity, though the whole amide group may be sterically unfavourable. Similarly, in most of the cases, the substituens at the phenyl moiety have been found to be beneficial to the inhibition potency and in many cases an electronic role of SO2 group of the sulfonylphenyl moiety has been indicated.

Quantitative structure–Activity relationship studies on some nonbenzodiazepine series of compounds acting at the benzodiazepine receptor

Quantitative structure-activity relationship (QSAR) studies have been made on a few non-benzodiazepine series of compounds such as 3-substituted imidazo[1,2-b]pyridazines, 2-phenylimidazo[1,2-alpha]pyridines, 2-(alkoxycarbonyl) imidazo[2,1-b]benzothiazoles, and 2-arylquinolines. For the first series of compounds a Fujita-Ban approach has been followed, which revealed the highest activity contribution for 3,4-OCH2O group of 2-phenyl moiety and for a methoxy group at 6-position. For the rest of the series, a Hansch approach has been adopted. The hydrophobic and electronic properties of the various substituents have been found to play major roles in the binding of these compounds with the receptor. Based on these studies, a hypothetical model for the drug-receptor interaction has been proposed.

A quantitative structure–Activity relationship study on some sulfolanes and arylthiomethanes acting as HIV-1 protease inhibitors

A quantitative structure-activity relationship (QSAR) study on some sulfolanes and arylthiomethanes acting as human immunodeficiency virus-1 (HIV-1) protease inhibitors reveals that in the case of sulfolanes an octahydropyrindene ring and a five-membered 3(S)-sulfolane ring with a hydrophobic 2-substituent (cis to 3-substituent) will be crucial for the inhibition activity. The binding of a sulfolane, which is a nonpeptidic molecule, with the enzyme is shown to partly mimic the binding of a peptidic inhibitor. The 2-substituent is found to have strong hydrophobic interaction with the receptor. Similarly, in the case of arylthiomethanes, one of the substituents of the methane is found to have strong hydrophobic interaction with the enzyme, while the aryl substituent (4-hydroxy-6-phenyl-2-oxo-2H-pyran-3-yl) is assumed to be involved in the hydrogen bondings.

A quantitative structure-activity relationship study on Clostridium histolyticum collagenase inhibitors: roles of electrotopological state indices.

A quantitative structure-activity relationship (QSAR) study has been made on eight different series of Clostridium histolyticum collegenase (ChC) inhibitors. These series are comprised of four different groups of sulfonylated amino acids and their corresponding hydroxamates. In each series, the inhibition potency of the compounds has been found to be significantly correlated with the electrotopological state (E-state) indices of nitrogen and sulfur atoms of the sulfonylated amino group in the molecules, showing the importance of the electronic characterstics of these atoms in controlling the inhibition potency of the compounds.

Neoadjuvant Chemotherapy Followed by Radical Surgery Versus Concomitant Chemotherapy and Radiotherapy in Patients With Stage IB2, IIA, or IIB Squamous Cervical Cancer: A Randomized Controlled Trial

Purpose We compared the efficacy and toxicity of neoadjuvant chemotherapy followed by radical surgery versus standard cisplatin-based chemoradiation in patients with locally advanced squamous cervical cancer. Patients and Methods This was a single-center, phase III, randomized controlled trial ( ClinicalTrials.gov identifier: NCT00193739). Eligible patients were between 18 and 65 years old and had stage IB2, IIA, or IIB squamous cervical cancer. They were randomly assigned, after stratification by stage, to receive either three cycles of neoadjuvant chemotherapy using paclitaxel and carboplatin once every 3 weeks followed by radical hysterectomy or standard radiotherapy with concomitant cisplatin once every week for 5 weeks. Patients in the neoadjuvant group received postoperative adjuvant radiation or concomitant chemotherapy and radiotherapy, if indicated. The primary end point was disease-free survival (DFS), defined as survival without relapse or death related to cancer, and secondary end points included overall survival and toxicity. Results Between September 2003 and February 2015, 635 patients were randomly assigned, of whom 633 (316 patients in the neoadjuvant chemotherapy plus surgery group and 317 patients in the concomitant chemoradiation group) were included in the final analysis, with a median follow-up time of 58.5 months. The 5-year DFS in the neoadjuvant chemotherapy plus surgery group was 69.3% compared with 76.7% in the concomitant chemoradiation group (hazard ratio, 1.38; 95% CI, 1.02 to 1.87; P = .038), whereas the corresponding 5-year OS rates were 75.4% and 74.7%, respectively (hazard ratio, 1.025; 95% CI, 0.752 to 1.398; P = .87). The delayed toxicities at 24 months or later after treatment completion in the neoadjuvant chemotherapy plus surgery group versus the concomitant chemoradiation group were rectal (2.2% v 3.5%, respectively), bladder (1.6% v 3.5%, respectively), and vaginal (12.0% v 25.6%, respectively). Conclusion Cisplatin-based concomitant chemoradiation resulted in superior DFS compared with neoadjuvant chemotherapy followed by radical surgery in locally advanced cervical cancer.

Quantitative structure–activity relationship study on some nonpeptidal cholecystokinin antagonists

A quantitative structure-activity relationship (QSAR) analysis has been performed on a series of 1,4-benzodiazepine derivatives, which were found to act as antagonists of cholecystokinin (CCK), a gastrointestinal peptide hormone. The CCK acts with three different receptor subtypes termed as CCK-A, CCK-B, and gastrin receptor, which can be found in peripheral system, brain, and stomach, respectively. With all the three subtypes, the binding of the compounds is found to significantly depend on the lipophilicity of the compounds and their ability to form the hydrogen bonds with the receptor. However, the binding sites in CCK-A receptor seem to be slightly rigid as compared to those in CCK-B or gastrin receptor. The latter two appear to have similar binding features.

A quantitative structure–activity relationship study on some aromatic/heterocyclic sulfonamides and their charged derivatives acting as carbonic anhydrase inhibitors

A quantitative structure–activity relationship (QSAR) study is made on a series of aromatic/heterocyclic sulfonamides and their charged derivatives acting as carbonic anhydrase (CA) inhibitors. These compounds were studied by Scozzafava et al. (J. Med. Chem. 2000; 43: 292) for the selective inhibition of CAs—sulfonamides generally do not discriminate between different CA isozymes and hence exhibit many undesirable side effects when used as drugs against a particular disease. In this communication, an attempt has been made to investigate the physicochemical and structural properties that can make them selective for a given CA isozyme. Based on in vitro data reported by Scozzafava et al. against two cytosolic isozymes and one membrane-bound isozyme, the QSAR study has shown that uncharged compounds cannot be made selective for cytosolic or membrane-bound isozyme since in both the cases the compounds appear to follow the same mechanism of inhibition. However, for the charged compounds the polarizability of the molecule seems to greatly favor the inhibition of the membrane-bound enzyme, and hence they can be made selective for this enzyme by enhancing their polarizability, which is found to play no role in the inhibition of cytosolic enzymes.