p-TSA-promoted syntheses of 5H-benzo[h] thiazolo[2,3-b]quinazoline and indeno[1,2-d] thiazolo[3,2-a]pyrimidine analogs: molecular modeling and in vitro antitumor activity against hepatocellular carcinoma

Antiproliferative, apoptotic and anti-inflammatory potential of 5H-benzo[h]thiazolo[2,3-b]quinazoline analogues: Novel series of anticancer compounds

Lung cancer (LC) is the most common cancer in males. As per GLOBOCAN 2020, 8.1 % of deaths and 5.9 % of cases of LC were reported in India. Our laboratory has previously reported the significant anticancer potential of 5H-benzo[h]thiazolo[2,3-b]quinazoline analogues. In this study, we have explored the anticancer potential of 7A {4-(6,7-dihydro-5H-benzo[h]thiazolo[2,3-b]quinazolin-7-yl)phenol} and 9A {7-(4-chlorophenyl)-9-methyl-6,7-dihydro-5H-benzo[h]thiazolo[2,3-b]quinazoline}by using in-vitro and in-vivo models of LC. In this study, we investigated the antiproliferative potential of quinazoline analogues using A549 cell line to identify the best compound of the series. The in-vitro and molecular docking studies revealed 7A and 9A compounds as potential analogues. We also performed acute toxicity study to determine the dose. After that, in-vivo studies using urethane-induced LC in male albino Wistar rats carried out further physiological, biochemical, and morphological evaluation (SEM and H&E) of the lung tissue. We have also evaluated the antioxidant level, inflammatory, and apoptotic marker expressions. 7A and 9A did not demonstrate any signs of acute toxicity. Animals treated with urethane showed a significant upregulation of oxidative stress. However, treatment with 7A and 9A restored antioxidant markers near-normal levels. SEM and H&E staining of the lung tissue demonstrated recovered architecture after treatment with 7A and 9A. Both analogues significantly restore inflammatory markers to normal level and upregulate the intrinsic apoptosis protein expression in the lung tissue. These experimental findings demonstrated the antiproliferative potential of the synthetic analogues 7A and 9A, potentially due to their anti-inflammatory and apoptotic properties.

Antiproliferative effect of indeno[1,2-d]thiazolo[3,2-a]pyrimidine analogues on IL-6 mediated STAT3 and role of the apoptotic pathway in albino Wistar rats of ethyl carbamate-induced lung carcinoma: In-silico, In-vitro, and In-vivo study

Lung cancer (LC) ranks second most prevalent cancer in females after breast cancer and second in males after prostate cancer. Based on the GLOBOCAN 2020 report, India represented 5.9% of LC cases and 8.1% of deaths caused by the disease. Several clinical studies have shown that LC occurs because of biological and morphological abnormalities and the involvement of altered level of antioxidants, cytokines, and apoptotic markers. In the present study, we explored the antiproliferative activity of indeno[1,2-d]thiazolo[3,2-a]pyrimidine analogues against LC using in-vitro, in-silico, and in-vivo models. In-vitro screening against A549 cells revealed compounds 9B (8-methoxy-5-(3,4,5-trimethoxyphenyl)-5,6-dihydroindeno[1,2-d]thiazolo[3,2-a]pyrimidine) and 12B (5-(4-chlorophenyl)-5,6-dihydroindeno[1,2-d]thiazolo[3,2-a]pyrimidine) as potential pyrimidine analogues against LC. Compounds 9B and 12B were docked with different molecular targets IL-6, Cyt-C, Caspase9, and Caspase3 using AutoDock Vina 4.1 to evaluate the binding affinity. Subsequently, in-vivo studies were conducted in albino Wistar rats through ethyl-carbamate (EC)- induced LC. 9B and 12B imparted significant effects on physiological (weight variation), and biochemical (anti-oxidant [TBAR's, SOD, ProC, and GSH), lipid (TC, TG, LDL, VLDL, and HDL)], and cytokine (IL-2, IL-6, IL-10, and IL-1β) markers in EC-induced LC in albino Wistar rats. Morphological examination (SEM and H&E) and western blotting (IL-6, STAT3, Cyt-C, BAX, Bcl-2, Caspase3, and caspase9) showed that compounds 9B and 12B had antiproliferative effects. Accordingly, from the in-vitro, in-silico, and in-vivo experimental findings, we concluded that 9B and 12B have significant antiproliferative potential and are potential candidates for further evaluation to meet the requirements of investigation of new drug application.

Thiazolopyrimidine Scaffold as a Promising Nucleus for Developing Anticancer Drugs: a Review in Last Decade

The thiazolopyrimidine nucleus is a bioisostericanalog of purine and an important class of N-containing heterocycles. Thiazolopyrimidine scaffolds are considered a promising class of bioactive compounds that encompass diverse biological activities such as antibacterial, antiviral, antifungal, anticancer, corticotrophin-releasing factor antagonists, anti-inflammatory, antituberculosis, and glutamic receptors antagonists. Despite the importance of thiazolopyrimidines from a pharmacological viewpoint, there is hardly a comprehensive review on this important heterocyclic nucleus. Throughout the years, those scaffolds have been studied extensively for its anticancer properties and several compounds were designed, synthesized, and evaluated for their anticancer effects with activity in the µM to nM range. However, there are hardly any reviews covering the anticancer effects of thiazolopyrimidines. In this review, an effort was made to compile literatures covering the anticancer activity of thiazolopyrimidines reported in the last decade (2010-2020). Nearly thirty articles were reviewed and compounds which IC50 < 50 µM against at least 50% of the used cell lines were listed in this review. The best ten compounds (10a, 14b, 17g, 18,25e, 25k, 34e, 41i, 49a, & 49c) show the best anticancer activity against the corresponding cell lines during the last 10 years are highlighted. By highlighting the most active compounds, this review article sheds light on the structural features associated with the strongest anticancer effects to provide guidance to future research aiming to develop anticancer molecules.

Synthetic and Medicinal Perspective of Fused-Thiazoles as Anticancer Agents

BACKGROUND

Cancer is second leading disease after cardiovascular disease. Presently, Chemotherapy, Radiotherapy and use of chemicals are some treatments available these days. Thiazole and its hybrid compounds extensively used scaffolds in drug designing and development of novel anticancer agents due to their wide pharmacological profiles. Fused thiazole scaffold containing drugs are available in market as a promising group of anticancer agents.

METHODS

The detailed study has been done using different database that focused on potent thiazole hybrid compounds with anticancer activity. The literature included in this review is focused on novel fused thiazole derivatives exhibiting anticancer potency in last decade.

RESULTS

Literature suggested that thiazoles and its fused and linked congener serve excellent pharmacological profile as an anticancer agent. Various synthetic strategies for fused thiazole are also summarized in this article. Novel thiazole and its fused congener showed anticancer activity against various cancer cell lines.

INTERPRETATION

Thiazole is a promising scaffold reported in literature with broad range of biological activities. This article covers the thiazole compounds fused with other carbocyclic/heterocycle including benzene, imidazole, pyridine, pyrimidine, quinoline, phenothiazine, thiopyrano, steroids, pyrrole etc. with anticancer activity from last decades. Several inhibitors for breast cancer, colon cancer, melanoma cancer, ovarian cancer, tubulin cancer etc. were reported in this review. Thus, this review will definitely aid to develop a lead for the new selective anticancer agents in future.

Synthesis, Antibacterial, and Antioxidant Evaluation of Novel Series of Condensed Thiazoloquinazoline with Pyrido, Pyrano, and Benzol Moieties as Five- and Six-Membered Heterocycle Derivatives

A novel synthesis of thiazolo[2,3-b]quinazolines 4(a–e), pyrido[2′,3′:4,5]thiazolo[2,3-b]quinazolines {5(a–e), 6(a–e), and 7(a–e)}, pyrano[2′,3′:4,5]thiazolo[2,3-b]quinazolines 8(a–e), and benzo[4,5]thiazolo[2,3-b]quinazoloine9(a–e) derivatives starting from 2-(Bis-methylsulfanyl-methylene)-5,5-dimethyl-cyclohexane-1,3-dione 2 as efficient α,α dioxoketen dithioacetal is reported and the synthetic approaches of these types of compounds will provide an innovative molecular framework to the designing of new active heterocyclic compounds. In our study, we also present optimization of the synthetic method along with a biological evaluation of these newly synthesized compounds as antioxidants and antibacterial agents against the bacterial strains, like S. aureus, E. coli, and P. aeruginosa. Among all the evaluated compounds, it was found that some showed significant antioxidant activity at 10 μg/mL while the others exhibited better antibacterial activity at 100 μg/mL. The results of this study showed that compound 6(c) possessed remarkable antibacterial activity, whereas compound 9(c) exhibited the highest efficacy as an antioxidant. The structures of the new synthetic compounds were elucidated by elemental analysis, IR, ¹H-NMR, and ¹³C-NMR.

Fabrication of Imatinib Mesylate-Loaded Lactoferrin-Modified PEGylated Liquid Crystalline Nanoparticles for Mitochondrial-Dependent Apoptosis in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is a major cause of concern as it has substantial morbidity associated with it. Previous reports have ascertained the antiproliferative activity of imatinib mesylate (IMS) against diverse types of carcinomas, but limited bioavailability has also been reported. The present study envisaged optimized IMS-loaded lactoferrin (LF)-modified PEGylated liquid crystalline nanoparticles (IMS-LF-LCNPs) for effective therapy of IMS to HCC via asialoglycoprotein receptor (ASGPR) targeting. Results displayed that IMS-LF-LCNPs presented an optimum particle size of 120.40 ± 2.75 nm, a zeta potential of +12.5 ± 0.23 mV, and 73.94 ± 2.69% release. High-resolution transmission electron microscopy and atomic force microscopy were used to confirm the surface architecture of IMS-LF-LCNPs. The results of cytotoxicity and 4,6-diamidino-2-phenylindole revealed that IMS-LF-LCNPs had the highest growth inhibition and significant apoptotic effects. Pharmacokinetics and biodistribution studies showed that IMS-LF-LCNPs have superior pharmacokinetic performance and targeted delivery compared to IMS-LCNPs and plain IMS, which was attributed to the targeting action of LF that targets the ASGPR in hepatic cells. Next, our in vivo experiment established that the HCC environment existed due to suppression of BAX, cyt c, BAD, e-NOS, and caspase (3 and 9) genes, which thus owed upstream expression of Bcl-xl, iNOS, and Bcl-2 genes. The excellent therapeutic potential of IMS-LF-LCNPs began the significant stimulation of caspase-mediated apoptotic signals accountable for its anti-HCC prospect. ¹H nuclear magnetic resonance (serum) metabolomics revealed that IMS-LF-LCNPs are capable of regulating the disturbed levels of metabolites linked to HCC triggered through N-nitrosodiethylamine. Therefore, IMS-LF-LCNPs are a potentially effective formulation against HCC.

Pharmacophore modeling, design, and synthesis of potent antihypertensives, oxazolo/thiazolo-[3,2-a]-pyrimidin-3(2H)-one, and 1,5-dihydroimidazo-[1,2-a]-pyrimidin-3(2H)-one derivatives: A pilot trial

An improved pharmacophore model, molecular properties, geometric analyses, and SAR led to synthesize oxazolo/thiazolo-[3,2-a]-pyrimidin-3(2H)-one, and 1,5-dihydroimidazo-[1,2-a]-pyrimidin-3(2H)-one derivatives exhibiting potent anti-hypertensive activity. The 6-ethoxycarbonyl-2,7-dimethyl-5-phenyl-1,5-dihydroimidazo[3,2-a]pyrimidin-3(2H)-one (4g), and 6-ethoxycarbonyl-2,7-dimethyl-5-(3-methyl-phenyl)-1,5-dihydroimidazo[3,2-a]pyrimidin-3(2H)-one (4h) showed significant reduction in mean arterial blood pressure (MABP, mm/Hg) of 79.78%, and 92.95% in 6 and 12 h durations, respectively, at 1.5 mg/kg body-weight dose, while at 3.0 mg/kg body-weight dose, the MABP reduction was achieved at 95.46%, and 92.02%, respectively, in 6 and 12 h durations, as compared to the standard drug, nifedipine.

Assessments of in vitro and in vivo antineoplastic potentials of β-sitosterol-loaded PEGylated niosomes against hepatocellular carcinoma

β-sitosterol (BS), a phytosterol, exhibits ameliorative effects on hepatocellular carcinoma (HCC) due to its antioxidant activities. However, its poor aqueous solubility and negotiated bioavailability and short elimination half-life is a huge limitation for its therapeutic applications. To overcome these two shortcomings, BS-loaded niosomes were made to via, film hydration method and process parameters were optimized using a three-factor Box-Behnken design. The optimized formulation (BSF) was further surface-modified with polyethylene glycol (PEG). The resulting niosomes (BSMF) have spherical shapes, particle sizes, 219.6 ± 1.98 nm with polydispersity index (PDI) and zeta potential of 0.078 ± 0.04 and -19.54 ± 0.19 mV, respectively. The drug loading, entrapment efficiency, and drug release at 24 h of the BSMF were found to be 16.72 ± 0.09%, 78.04 ± 0.92%, and 75.10 ± 3.06%, respectively. Moreover, BSMF showed significantly greater cytotoxic potentials on Hep G2 cells with an enhanced cellular uptake relative to pure BS and BSF. The BSMF also displayed potentially improved curative property of HCC in albino wistar rat. Thus, the BSMF could be one of the promising therapeutic modalities for HCC treatment in terms of targeting potential resulting in enhanced therapeutic efficacy.

Augmented Therapeutic Efficacy of Naringenin Through Microemulsion-Loaded Sericin Gel Against UVB-Induced Photoaging

Naringenin (NAR) is a flavonoid found in citrus fruits such as grapes and oranges. Recently, NAR has demonstrated its potential in inhibition of photoaging. The aim of the present study was to investigate the efficacy of sericin (SR) gel loaded with NAR microemulsion (ME) to inhibit UVB-induced photoaging and prevention of epidermoid carcinoma in animal model. NAR -ME was prepared and optimized through Box-Behnken design. The optimized ME was loaded into sericin (SR) gel. The formulations were subjected to various in vitro, in vivo and cytotoxicity studies over A431 cell lines. The optimized ME revealed a globule size of 249.05 ± 3.78 nm, 6.7 ± 0.5 pH and 73.1 ± 2.11% release over a period of 24 h respectively. Cytotoxicity studies revealed a depression in IC₅₀ value in NAR -ME (65.11 ± 1.54 μg/ml) when compared with NAR (118.1 ± 2.09 μg/ml). The NAR-ME-SR gel displayed enhanced therapeutic potential when compared with plain NAR, in terms of augmented antiproliferative activity. Graphical abstract.

Synthesis and antitumor activity of isolongifoleno[7,8-d]thiazolo[3,2-a]pyrimidine derivatives via enhancing ROS level

A series of novel isolongifoleno[7,8-d]thiazolo[3,2-a]pyrimidine derivatives (4a-4x) were synthesized from isolongifolanone according fragment-based design strategy, and their anticancer activity against human aortic smooth muscle cells (HASMC), human breast cancer (MCF-7) cells, human cervical cancer (HeLa) cells, and human liver cancer (HepG2) cells were investigated. Results of the anticancer activity illustrated that most of the compounds showed potent antitumor activity and compound 4i proved to be the most active derivative with IC₅₀ values of 0.33 ± 0.24 (for MCF-7 cells), 0.52 ± 0.13 (for HeLa cells), and 3.09 ± 0.11 μM (for HepG2 cells), respectively. Moreover, we assessed the effects of 4i on cell apoptosis, cell cycle distribution, mitochondrial membrane potential, and reactive oxygen species (ROS) generation. The results indicated that compound 4i altered mitochondrial membrane potential and produced ROS leading to cell apoptosis of MCF-7 cells in a dose-dependent manner, however, without affecting cell cycle progression. These findings suggested that 4i was an effective compound and provided a promising candidate for anticancer drugs.

Poly(lactic-co-glycolic acid)-loaded nanoparticles of betulinic acid for improved treatment of hepatic cancer: characterization, in vitro and in vivo evaluations

PURPOSE

The application of betulinic acid (B), a potent antineoplastic agent, is limited due to poor bioavailability, short plasma half-life and inappropriate tissue distribution. Thus, we aimed to prepare novel 50:50 poly(lactic-co-glycolic acid) (PLGA)-loaded B nanoparticles (BNP) and to compare its anti-hepatocellular carcinoma (HCC) activity with parent B.

METHODS

BNP were synthesized and characterized using different methods such as scanning electron microscopy (SEM), fourier-transform infrared (FTIR) spectrometry and particle size analyses. Particle size of BNP was optimized through the application of the stabilizer, polyvinyl alcohol (PVA). The anti-HCC response was evaluated through in vitro cell line study using Hep-G2 cells, confocal microscopy, in vivo oral pharmacokinetics and animal studies. Further, quantitative reverse transcription polymerase chain reaction (qRT-PCR) analysis was conducted to observe the changes in the expression of specific genes.

RESULTS

Particle size of BNP was optimized through the application of the stabilizer, polyvinyl alcohol. Physicochemical characterization exhibited particle size of 257.1 nm with zeta potential -0.170 mV (optimized batch B, BNP). SEM and FTIR analyses of BNP showed that cylindrical particles of B converted to spherical particles in BNP and there were no interaction between B and used polymers. The release study of optimized BNP was highest (≥80%) than any other formulation. Later, in vitro cell culture analysis using Hep-G2 cells and confocal microscopy studies revealed that BNP had the highest inhibition and penetration properties than parent B. Oral pharmacokinetics studies using albino Wistar rats at single 100 mg dose again exhibited BNP had the higher 50% of plasma concentration (t1/2), a higher maximum plasma concentration (Cmax) and took longer to reach the maximum plasma concentration (Tmax) than parent B. Next, our in vivo study using nitrosodiethyl amine (NDEA)-induced HCC model documented BNP decreased in number of nodules, restored body weight, oxidative stress parameters, liver marker enzymes and histological architecture than parent B. Lastly, qRT-PCR studies further demonstrated that anti-HCC properties of BNP may be due to over expression of antiapoptotic caspases i.e., caspase 3 and 8.

CONCLUSION

The prepared BNP showed a better therapeutic response against HCC and could be attributed as future candidate molecule for HCC treatment.

5H-benzo[h]thiazolo[2,3-b]quinazolines ameliorate NDEA-induced hepatocellular carcinogenesis in rats through IL-6 downregulation along with oxidative and metabolic stress reduction

5H-benzo[h]thiazolo[2,3-b]quinazoline scaffold is known to have an antitumor effect on certain types of malignancies; however, its effect on hepatocellular carcinoma (HCC) remains unclear. Previously, we reported p-toluenesulfonic acid-promoted syntheses, molecular modeling and in vitro antitumor activity of 5H-benzo[h]thiazolo[2,3-b]quinazoline against human hepatoma (Hep-G2) cells where compounds 4A and 6A were found to be potent inhibitors among the series. In continuation to our previous effort to develop novel therapeutic strategies for HCC treatment, here we investigated the in vivo antitumor activity and the mechanism underlying the effects of 4A and 6A in N-nitrosodiethylamine (NDEA)-induced HCC using male Wistar rats. NDEA was administered weekly intraperitoneally at a dose of 100 mg/kg for 6 weeks. Various physiological and morphological changes, oxidative parameters, liver marker enzymes and cytokines were assessed to evaluate the antitumor effect of 4A and 6A. In addition, proton nuclear magnetic resonance-based serum metabolomics were performed to analyze the effects of 4A and 6A against HCC-induced metabolic alterations. Significant tumor incidences with an imbalance in carcinogen metabolizing enzymes and cellular redox status were observed in carcinogenic rats. Tumor inhibitory effects of 4A and 6A were noted by histopathology and biochemical profiles in NDEA-induced hepatic cancer. Compounds 4A and 6A had a potential role in normalizing the elevated levels of inflammatory mediators such as interleukin-1β (IL-1β), IL-2, IL-6 and IL-10. At molecular level, the real-time quantitative reverse-transcribed polymerase chain reaction analysis revealed that 4A and 6A attenuated the IL-6 gene overexpression in hepatic cancer. Further, orthogonal partial least squares discriminant analysis scores plot demonstrated a significant separation of 4A and 6A-treated groups from carcinogen control group. Both the compounds have potential to restore the imbalanced metabolites due to HCC, signifying promising hepatoprotective activities. All these findings suggested that 4A and 6A could be potential drug candidates to treat HCC.