Molecular Insights on Selective and Specific Inhibitors of Cyclin Dependent Kinase 9 Enzyme (CDK9) for the Purpose of Cancer Therapy

Cyclin Dependent Kinase 9 (CDK9), which controls transcriptional elongation, is a promising pharmacological target for a variety of cancerous cells, specifically those characterized by transcriptional dysregulation. CDK9 promotes the pause or release of RNA polymerase II, a rate-limiting stage in normal transcriptional regulation that is often disturbed in cancers. New indications suggest that selective CDK9 antagonism may be beneficial in the treatment of some cancers. CDK9 modulators (inhibitors and degraders) have gained a lot of attention recently, and many molecules are currently in clinical trials. In this review, the CDK9 antagonists under clinical and preclinical trials have been discussed, as well as the structure-activity relationship has been studied, which will help scientists generate more target- specific drug molecules in the future with less toxicity.

IND-2, a Quinoline Derivative, Inhibits the Proliferation of Prostate Cancer Cells by Inducing Oxidative Stress, Apoptosis and Inhibiting Topoisomerase II

In men, prostate cancer (PC) is the most frequently diagnosed cancer, causing an estimated 375,000 deaths globally. Currently, existing therapies for the treatment of PC, notably metastatic cases, have limited efficacy due to drug resistance and problematic adverse effects. Therefore, it is imperative to discover and develop novel drugs for treating PC that are efficacious and do not produce intolerable adverse or toxic effects. Condensed quinolines are naturally occurring anticancer compounds. In this study, we determined the in vitro efficacy of IND-2 (4-chloro-2-methylpyrimido[1″,2″:1,5]pyrazolo[3,4-b]quinolone) in the PC lines, PC-3 and DU-145. IND-2 significantly inhibited the proliferation of PC-3 and DU-145, with IC₅₀ values of 3 µM and 3.5 µM, respectively. The incubation of PC-3 cells with 5 and 10 µM of IND-2 caused the loss of the mitochondrial membrane potential in PC-3 cells. Furthermore, IND-2, at 5 µM, increased the expression of cleaved caspase-3, cleaved caspase-7 and cleaved poly (ADP-ribose) polymerase (PARP). The incubation of PC-3 cells with 5 µM of IND-2 significantly decreased the expression of the apoptotic protein, B-cell lymphoma 2 (Bcl-2). Furthermore, 5 and 10 µM of IND-2 produced morphological changes in PC-3 cells characteristic of apoptosis. Interestingly, IND-2 (2.5, 5 and 10 µM) also induced mitotic catastrophe in PC-3 cells, characterized by the accumulation of multinuclei. The incubation of DU-145 cells with 1.25 and 5 μM of IND-2 significantly increased the levels of reactive oxygen species (ROS). Finally, IND-2, at 10 μM, inhibited the catalytic activity of topoisomerase IIα. Overall, our findings suggest that IND-2 could be a potential lead compound for the development of more efficacious compounds for the treatment of PC.

Incisional hernia following colorectal cancer surgery according to suture technique: Hughes Abdominal Repair Randomized Trial (HART)

BACKGROUND

Incisional hernias cause morbidity and may require further surgery. HART (Hughes Abdominal Repair Trial) assessed the effect of an alternative suture method on the incidence of incisional hernia following colorectal cancer surgery.

METHODS

A pragmatic multicentre single-blind RCT allocated patients undergoing midline incision for colorectal cancer to either Hughes closure (double far-near-near-far sutures of 1 nylon suture at 2-cm intervals along the fascia combined with conventional mass closure) or the surgeon's standard closure. The primary outcome was the incidence of incisional hernia at 1 year assessed by clinical examination. An intention-to-treat analysis was performed.

RESULTS

Between August 2014 and February 2018, 802 patients were randomized to either Hughes closure (401) or the standard mass closure group (401). At 1 year after surgery, 672 patients (83.7 per cent) were included in the primary outcome analysis; 50 of 339 patients (14.8 per cent) in the Hughes group and 57 of 333 (17.1 per cent) in the standard closure group had incisional hernia (OR 0.84, 95 per cent c.i. 0.55 to 1.27; P = 0.402). At 2 years, 78 patients (28.7 per cent) in the Hughes repair group and 84 (31.8 per cent) in the standard closure group had incisional hernia (OR 0.86, 0.59 to 1.25; P = 0.429). Adverse events were similar in the two groups, apart from the rate of surgical-site infection, which was higher in the Hughes group (13.2 versus 7.7 per cent; OR 1.82, 1.14 to 2.91; P = 0.011).

CONCLUSION

The incidence of incisional hernia after colorectal cancer surgery is high. There was no statistical difference in incidence between Hughes closure and mass closure at 1 or 2 years.

REGISTRATION NUMBER

ISRCTN25616490 (http://www.controlled-trials.com).

Substituent Orchestration in Dimethylquinoxaline Derivatives: A Tool for Fishing Out Appropriate CDK5 Inhibitors as Potential Therapeutics for Alzheimer's

A set of new heterocyclic analogs (Compounds I-IX), comprising of 6,7 dimethyl Quinoxalines were found to be active against the receptor GSK3β (Compounds IV-V) (Chem. Biodiversity 2021, 18, e2100364). In an effort to modulate effective CDK5 inhibitors herein our hypothesis underpinned to fish out an appropriate derivative from the same quinoxaline series, as these two targets GSK3β and CDK5 shared structural resemblance with each other. Aligned to the goal we have synthesized Compounds I-IX, characterized them using a combination of spectroscopic techniques and evaluated their activities against CDK5. Our analysis reflected that the adjacently located alkoxy/hydroxy functionality derivatives namely Compounds III and VI, to be the most potent (micromolar) amongst others in the series, backed by Density Functional Theory (DFT) calculations and molecular modelling studies. Also, the efficacy of the Compounds I-IX, were monitored in few other members of the CMGC family namely DYRK1A, CLK1and CK1δ that have been known to be directly involved in hyperphosphorylation of Tau. But unfortunately in none of the targets, our quinoxaline series were active. In a nut shell further optimisation of these intelligent nucleus, would not only lead to the discovery of novel pharmacophores, but also marked selectivity against a pool of kinases, thereby implementing a distinct roadmap towards the design of potential therapeutics against Alzheimer's.

Primary Ewing sarcoma of the kidney: A series of four cases

INTRODUCTION

Ewing sarcoma (ES), the neuroectodermal derived tumour typically occurs in the bone and soft tissue of children and young adults. Primary ES of the kidney is strikingly rare and only a few cases and small case series have been documented. Due to the highly aggressive nature of this neoplasm, distinction from other morphological mimickers is truly indispensable in terms of treatment and prognosis. Here we describe the clinicopathological features of four cases of primary ES of the kidney with special emphasis on one case having extensive neural differentiation postneo- adjuvant chemotherapy (NACT). Extensive neural differentiation in renal ES has not been documented to date.

CASE SERIES

Four patients (age range from 15-35 years) had kidney mass and multiple distant metastases at first presentation. Primary diagnosis of Ewing sarcoma was rendered by histopathology with the help of immunohistochemistry on core biopsy material. Tumour cells in all cases showed diffuse membranous CD99, nuclear FLI-1 and NKX2.2. Two of the patients had undergone radical nephrectomy followed by combination chemotherapy. Another two patients were first treated with neo-adjuvant chemotherapy (NACT) followed by radical nephrectomy. In one of them, histopathological examination of nephrectomy specimens revealed extensive neural differentiation. The adrenal gland was free in all four cases. The follow-up period was 12 -24 months. Three patients had survived and one of them became disease-free.

CONCLUSION

Primary ES of the kidney is a rare and lethal entity. Due to overwhelming rarity, chemotherapy protocol has not been standardised and followed as ES in bone/soft tissue. Histopathological confirmation and prompt initiation of treatment may improve patient survival and outcome.

A Molecular Insight into Pyrazole Congeners as Antimicrobial, Anticancer, and Antimalarial Agents

BACKGROUND

Pyrazole is a bioactive heterocyclic congener found in a wide range of biological and pharmacological applications. Due to their multiple prospective uses, developing innovative pyrazoles and analogues, disclosing revolutionary ways for synthesizing this nucleus, investigating diverse potencies of that heterocycle, and seeking for possible applications of pyrazoles are all growing more significant Objectives: Pyrazole scaffolds have been proven to be successful as antimicrobial, anticancer, antimalarial therapeutic against multiple targets like DNA gyrase, topoisomerase IV, Hsp90, and several kinase enzymes. Its moiety has absorbed the attention of many scientists to research chemical and pharmacological profile due to this miscellany in the biotic region.

RESULTS

The review covers pyrazole scaffolds with a variety of biological functions, as well as attempts to connect the structure-activity relationship. Multiple pyrazole analogues have been produced as lead compounds, and their activities have been evaluated.

CONCLUSION

The combination of pyrazole with other pharmacophores in a molecule might lead to novel potent therapeutic medicines, which could aid in the development of potent lead compounds.

The Emerging Role of Janus Kinase Inhibitors in the Treatment of Cancer

Cancer is a leading cause of death worldwide. The Janus kinase (JAK) signal transducer and activator of transcription (STAT) signalling pathway is activated abnormally, which promotes carcinogenesis. Several cytokines are important cancer drivers. These proteins bind to receptors and use the Janus kinase (JAK) and STAT pathways to communicate their responses. Cancer risks are linked to genetic differences in the JAK-STAT system. JAK inhibitors have shown to reduce STAT initiation, tissue propagation, and cell existence in preclinical investigations in solid tumour cell line models. JAK inhibitors, notably ruxolitinib, a, JAK1 or 2 blockers, make cell lines and mouse models more susceptible to radiotherapy, biological response modifier therapy, and oncolytic viral treatment. Numerous JAK antagonists have been or are now being evaluated in cancerous patients as monotherapy or by combining with other drugs in clinical studies. In preclinical investigations, certain JAK inhibitors showed promise anticancer effects; however, clinical trials explicitly evaluating their effectiveness against the JAK/STAT system in solid tumours have yet to be completed. JAK inhibition is a promising strategy to target the JAK/STAT system in solid tumours, and it deserves to be tested further in clinical studies. The function of directing Janus kinases (JAKs), an upstream accelerator of STATs, as a technique for lowering STAT activity in various malignant circumstances is summarized in this article, which will help scientists to generate more specific drug molecules in future.

Lead optimization of novel quinolone chalcone compounds by a structure-activity relationship (SAR) study to increase efficacy and metabolic stability

Many agents targeting the colchicine binding site in tubulin have been developed as potential anticancer agents. However, none has successfully made it to the clinic, due mainly to dose limiting toxicities and the emergence of multi-drug resistance. Chalcones targeting tubulin have been proposed as a safe and effective alternative. We have shown previously that quinolone chalcones target tubulin and maintain potent anti-proliferative activity vis-à-vis colchicine, while also having high tolerability and low toxicity in mouse models of cancer and refractivity to multi-drug resistance mechanisms. To identify the most effective anticancer chalcone compound, we synthesized 17 quinolone-chalcone derivatives based on our previously published CTR-17 and CTR-20, and then carried out a structure-activity relationship study. We identified two compounds, CTR-21 [((E)-8-Methoxy-3-(3-(2-methoxyphenyl)-3-oxoprop-1-enyl) quinolin-2(1H)-one)] and CTR-32 [((E)-3-(3-(2-ethoxyphenyl)-3-oxoprop-1-enyl) quinolin-2(1H)-one)] as potential leads, which contain independent moieties that play a significant role in their enhanced activities. At the nM range, CTR-21 and CTR-32 effectively kill a panel of different cancer cells originated from a variety of different tissues including breast and skin. Both compounds also effectively kill multi-drug resistant cancer cells. Most importantly, CTR-21 and CTR-32 show a high degree of selectivity against cancer cells. In silico, both of them dock near the colchicine-binding site with similar energies. Whereas both CTR-21 and CTR-32 effectively prevents tubulin polymerization, leading to the cell cycle arrest at G2/M, CTR-21 has more favorable metabolic properties. Perhaps not surprisingly, the combination of CTR-21 and ABT-737, a Bcl-2 inhibitor, showed synergistic effect in killing cancer cells, since we previously found the "parental" CTR-20 also exhibited synergism. Taken together, CTR-21 can potentially be a highly effective and relatively safe anticancer drug.

Unravelling the Selectivity of 6,7-Dimethyl Quinoxaline Analogs for Kinase Inhibition: An Insight towards the Development of Alzheimer's Therapeutics

Untangling the most selective kinase inhibitors via pharmacological intervention remains one of the challenging affairs to date. In accordance to this drift, herein we describe the design and synthesis of a set of new heterocyclic analogs consisting of 6,7-dimethyl Quinoxaline, appended to a connector, employing Schiff base strategy (Compounds I-IX). The compounds were characterized by various spectroscopic techniques and the kinase inhibition assay were performed on few prime members of the CMGC family namely the GSK3β, DYRK1A and CLK1 receptors, respectively, that have been known to be directly involved in hyperphosphorylation of Tau. Interestingly the biological evaluation results revealed that Compounds IV and V, with bromo/chloro functionalities in the aromatic core were advantaged of being highly selective towards the target GSK3β over others. To strengthen our analysis, we adopted molecular modelling studies, where compounds IV/V were redocked in the same grid 4AFJ, as that of the reference ligand, 5-aryl-4-carboxamide-1,3-oxazole. Surprisingly, our investigation underpinned that for both the compounds IV/V, a primary H-bonding existed between the designed molecules (IV/V) and Val 135 residue in the receptor GSK3β, in line with the reference ligand. We attribute this interaction to instigate potency in the compounds. Indeed the other non-covalent interaction, between the derivative's aromatic nucleus and Arg 141/Thr 138 in the receptor GSK3β, might have been responsible for enhancing the selectivity in the targets. Overall, we feel that the present work depicts a logical demonstration towards fine tuning the efficacy of the inhibitors through systematic adjustment of electron density at appropriate positions in the aromatic ring be it the main quinoxaline or the other aromatic nucleus. Thus this pathway offers a convenient strategy for the development of efficient therapeutics for diversified neurodegenerative diseases like that of Alzheimer's.

Alkylating Agents, the Road Less Traversed, Changing Anticancer Therapy

Cancer is considered one of the gruelling challenges and poses a grave health hazard across the globe. According to the International Agency for Research on Cancer (IARC), new cancer diagnoses increased to 18.1 million in 2018, with 9.6 million deaths, bringing the global cancer rate to 23.6 million by 2030. In 1942, the discovery of nitrogen mustard as an alkylating agent was a tremendous breakthrough in cancer chemotherapy. It acts by binding to the DNA, and creating cross linkages between the two strands, leading to arrest of DNA replication and eventual cell death. Nitrogen lone pairs of 'nitrogen mustard' produce an intermediate 'aziridinium ion' at molecular level, which is very reactive towards DNA of tumour cells, resulting in multiple side effects with therapeutic consequences. Owing to its high reactivity and peripheral cytotoxicity, several improvements have been made with structural modifications for the past 75 years to enhance its efficacy and improve the direct transport of drugs to the tumour cells. Alkylating agents were among the first non-hormonal substances proven to be active against malignant cells and also, the most valuable cytotoxic therapies available for the treatment of leukaemia and lymphoma patients. This review focus on the versatile use of alkylating agents and the structure activity relationship (SAR) of each class of these compounds. This could provide an understanding for design and synthesis of new alkylating agents having enhanced target specificity and adequate bioavailability.

Antiproliferative Efficacy of N-(3-chloro-4-fluorophenyl)-6,7-dimethoxyquinazolin-4-amine, DW-8, in Colon Cancer Cells Is Mediated by Intrinsic Apoptosis

A novel series of 4-anilinoquinazoline analogues, DW (1–10), were evaluated for anticancer efficacy in human breast cancer (BT-20) and human colorectal cancer (CRC) cell lines (HCT116, HT29, and SW620). The compound, DW-8, had the highest anticancer efficacy and selectivity in the colorectal cancer cell lines, HCT116, HT29, and SW620, with IC₅₀ values of 8.50 ± 2.53 µM, 5.80 ± 0.92 µM, and 6.15 ± 0.37 µM, respectively, compared to the non-cancerous colon cell line, CRL1459, with an IC₅₀ of 14.05 ± 0.37 µM. The selectivity index of DW-8 was >2-fold in colon cancer cells incubated with vehicle. We further determined the mechanisms of cell death induced by DW-8 in SW620 CRC cancer cells. DW-8 (10 and 30 µM) induced apoptosis by (1) producing cell cycle arrest at the G2 phase; (2) activating the intrinsic apoptotic pathway, as indicated by the activation of caspase-9 and the executioner caspases-3 and 7; (3) nuclear fragmentation and (4) increasing the levels of reactive oxygen species (ROS). Overall, our results suggest that DW-8 may represent a suitable lead for developing novel compounds to treat CRC.

A Novel Dialkylamino-Functionalized Chalcone, DML6, Inhibits Cervical Cancer Cell Proliferation, In Vitro, via Induction of Oxidative Stress, Intrinsic Apoptosis and Mitotic Catastrophe

In this study, we designed, synthesized and evaluated, in vitro, novel chalcone analogs containing dialkylamino pharmacophores in the cervical cancer cell line, OV2008. The compound, DML6 was selective and significantly decreased the proliferation of OV2008 and HeLa cells in sub-micromolar concentrations, compared to prostate, lung, colon, breast or human embryonic kidney cell line (HEK293). DML6, at 5 μM, arrested the OV2008 cells in the G2 phase. Furthermore, DML6, at 5 μM, increased the levels of reactive oxygen species and induced a collapse in the mitochondrial membrane potential, compared to OV2008 cells incubated with a vehicle. DML6, at 5 μM, induced intrinsic apoptosis by significantly (1) increasing the levels of the pro-apoptotic proteins, Bak and Bax, and (2) decreasing the levels of l the anti-apoptotic protein, Bcl-2, compared to cell incubated with a vehicle. Furthermore, DML6, at 5 and 20 μM, induced the cleavage of caspase-9, followed by subsequent cleavage of the executioner caspases, caspase-3 and caspase-7, which produced OV2008 cell death. Overall, our data suggest that DML6 is an apoptosis-inducing compound that should undergo further evaluation as a potential treatment for cervical cancer.

Biodistribution and pharmacokinetic studies on topically delivered technetium-99m-labeled 5-FU nanogel formulation for management of pre-cancerous skin lesions

Purpose: To prepare technetium-99m (99mTc)-labelled nanogel loaded with 5-fluorouracil (5-FU) containing synthesized gallic acid-stearylamine (GA-SA) conjugate in order to reduce its systemic toxicity and provide site-specific delivery to skin lesions. Methods: Lipid nanocarrier-based 1 % (w/w) 5-FU nanogel containing GA-SA conjugate was successfully formulated. Parameters that included pH, viscosity and entrapment efficiency were measured. Furthermore, 1 % (w/w) 5-FU nanogel and 1 % (w/w) 5-FU commercial formulations were radiolabelled with 99mTc. The radiolabelled 99mTc-5-FU nanogel and commercial formulations were subjected to successive preclinical assessments with respect to radiochemical stability, biodistribution, and gamma scintigraphy in BALB/c mice, and pharmacokinetic studies in New Zealand albino rabbits. Results: The entrapment efficiency of 5-FU in the nanogel preparation was 82.12 ± 1.2 %. The 5-FU nanogel formulation exhibited excellent radiolabelling efficiency (> 93 %) and high stability. Skin/blood localization ratios of 274.93 and 167.89 were obtained for topical radiolabelled drug-loaded 5-FU nanogel formulation and 5-FU commercial formulation, respectively, after 1 h of administration. Gamma scintigraphy and biodistribution studies showed that topically administered 99mTc-5-FU nanogel was distributed mostly in skin, when compared to marketed 5-FU formulation. Pharmacokinetic studies revealed low maximum activity in the blood (Cmax = 34.20 µg/mL), with low intensity (AUC) for topically administered 99mTc-5-FU nanogel formulation. Conclusion: 5-FU nanogel enhances specific delivery of 5-FU at targeted sites and decreases its toxicity in tissues distant from the site of application. The results suggest that nanogel loaded with 5-FU containing synthesized GA-SA conjugate is a novel effective approach for the treatment of skin lesions.

Synergistic anti-cancer activity of combined 5-fuorouracil and gallic acid-stearylamine conjugate in A431 human squamous carcinoma cell line

Purpose: To evaluate the individual and synergistic anti-cancer effects of 5-fuorouracil (5-FU) and synthesized gallic acid-stearylamine (GA-SA) conjugate in A431 human squamous cancer cell line. Methods: Characterisation of the synthesised conjugate was performed using Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR), and mass spectrometry (MS). The synergistic effect of the combination therapy (5-FU/GA-SA) was assessed by determining their inhibitory concentration (IC30) whereby A431 cells were treated with 5-FU:GA–SA conjugate at various ratios ranging from 5:1 to 1:5. Results: The cytotoxicity of 5-FU was 29 %, while that of the combination of 5-FU with GA–SA conjugate was as high as 60 %. Thus, this combination showed significant synergistic enhancement in cytotoxicity (p < 0.05). The results obtained also revealed that the IC30 values of 5-FU and the GA–SA conjugate were 1 and 10 µg/mL, respectively. The IC30 values of the combination ratios indicated that the dosages used in the study were safe in HaCaT normal cell line. Conclusion: These results indicate that 5-FU/GA–SA conjugate at a ratio of 1:1 is effective against A431 cell line (cancer cells)) but safe in HaCaT cell lines (normal cells).

Virtual Screening Based Discovery of PTP1B Inhibitors and Their Biological Evaluations

Background :

The discovery of novel antidiabetics for the treatment of type 2 diabetes mellitus (T2DM) is an important task nowadays because the current treatment approaches have certain limitations. The reported studies showed that the protein tyrosine phosphatase 1B (PTP1B) is a valuable target, can be used to develop significant antidiabetic molecules.

Objective:

In the present investigation, computational methods and biological evaluation studies have been applied to develop novel PTP1B inhibitors with good enzyme binding affinity and activity.

Methods:

Virtual screening (docking) analysis of SPECS database compounds on PTP1B enzyme was performed using Schrodinger software. In vitro and in vivo biological evaluations had been conducted with the identified hits.

Results:

The results revealed that the molecules identified through these studies have shown significant interactions with the active site residues of the PTP1B enzyme. The compounds S1 and S2 provided significant binding interactions with the residues (Arg221 and Gln262) and have shown considerable in vitro PTP1B inhibitory activity and in vivo antidiabetic activity. The compounds S1 and S2 possessed 35.44±0.12% and 33.68±0.08% inhibitory activities, respectively.

Conclusion:

These identified hits will be used as a template for design and development of novel PTP1B inhibitors with a compatible pharmacokinetic profile.

Flavonoids as Multi-Target Compounds: A Special Emphasis on their Potential as Chemo-adjuvants in Cancer Therapy

Flavonoids are low molecular weight, polyphenolic phytochemicals, obtained from secondary metabolism of various plant compounds. They have a spectrum of pharmacological efficacies, including potential anticancer efficacy. Natural flavonoids are present in fruits, vegetables, grains, bark, roots, stems, flowers, tea and wine. Flavonoids can attenuate or inhibit the initiation, promotion and progression of cancer by modulating various enzymes and receptors in diverse pathways that involve cellular proliferation, differentiation, apoptosis, inflammation, angiogenesis and metastasis. Furthermore, in vitro, flavonoids have been shown to reverse multidrug resistance when used as chemo-adjuvants. Flavonoids (both natural and synthetic analogues) interact with several oncogenic targets through dependent and independent mechanisms to mediate their anticancer efficacy in different types of cancer cells.

Recent Advances in Protein Tyrosine Phosphatase 1B Targeted Drug Discovery for Type II Diabetes and Obesity

BACKGROUND

Protein tyrosine phosphatase 1B (PTP1B) is an important therapeutic target for type II diabetes and obesity because of its pivotal role as a negative modulator in both insulin and leptin signalling pathways.

OBJECTIVE

The discovery of PTP1B inhibitors has been the focus of researchers in both academia and pharmaceutical industry over the last two decades.

RESULTS AND CONCLUSION

Though, intense pharmaceutical research in this area has resulted in many potent PTP1B inhibitors, a vast majority of them possessed pTyr mimetic group such as phosphonates, carboxylic acids and sulphamic acids, which led to poor PTP1B selectivity and insufficient in vivo efficacy due to low cell permeability and bioavailability. The availability of X-ray crystallographic structures of PTP1B together with the application of molecular modelling and other innovative strategies led to the development of many potent and selective PTP1B inhibitors with desirable physicochemical properties. This review traces the development of PTP1B inhibitors over the last decade and also records novel PTP1B inhibitors developed recently with greater emphasis on their selectivity and cell permeability.

Analysis of HLA-G expression in renal tissue in lupus nephritis: a pilot study

BACKGROUND

The study aimed to investigate whether HLA-G antigen is expressed in the kidneys of patients affected by lupus nephritis (LN) and whether its detection in renal biopsies could be adopted as a marker of treatment response and prognosis.

METHODS

Thirty renal biopsies from patients with LN were selected and analyzed through immunohistochemistry. Laboratory and clinical data were retrospectively collected at baseline, 6 and 12 months and at the latest clinical appointment. A number of patients (63.3%) were treated with rituximab (RTX) +/- methylprednisolone in the induction phase. The expression of HLA-G in glomeruli, tubules and infiltrating cells was examined and compared between lupus patients who achieved either complete or partial renal response and those who did not respond to treatment.

RESULTS

HLA-G staining was observed in the glomeruli of 20 of 30 samples from patients with LN. The expression of the antigen was detected in podocytes, along glomerular capillary walls, on parietal glomerular epithelial cells and within the juxtaglomerular apparatus. Seventy per cent of patients whose glomeruli expressed HLA-G achieved partial or complete response at 6 months and 75% at the latest available follow up compared with 30% and 40%, respectively, of those who did not show any expression. The pattern of staining in tubules and infiltrating cells was highly variable precluding any clinical correlation.

CONCLUSION

This study demonstrates that HLA-G is expressed in renal tissue in LN. Our retrospective data suggest that its expression could correlate with response to treatment.

Novel 3-((2-chloroquinolin-3-yl)methylene)indolin-2-one derivatives produce anticancer efficacy in ovarian cancer in vitro

A novel series of 3-((2-chloroquinolin-3-yl)methylene)indolin-2-ones were synthesized, using the ‘molecular hybridization approach’ and evaluated for anticancer efficacy. Eleven 3-((2-chloroquinolin-3-yl)methylene)indolin-2-ones (LM01 to LM11) were synthesized and evaluated for in vitro cytotoxic efficacy in cancer (ovarian, prostate and colon) and two non-cancerous cell lines. Among the 3-((2-chloroquinolin-3-yl)methylene)indolin-2-one derivatives, LM08, with a 6-Cl substitution in the 3-quinolinyl moiety, had selective and potent cytotoxic efficacy in the ovarian cancer cell line A2780. Further mechanistic investigations indicated that LM08 significantly inhibited the clonogenic survival of A2780 cancer cells, which was mediated by inducing apoptosis.

Unravelling the potency of 4,5-diamino-4H-1,2,4 triazole-3-thiol derivatives for kinase inhibition using a rational approach

This report describes the design of potent kinase inhibitors by simply fine tuning the surroundings of triazole core with diversified derivatization.

Bax/Tubulin/Epithelial-Mesenchymal Pathways Determine the Efficacy of Silybin Analog HM015k in Colorectal Cancer Cell Growth and Metastasis

The inhibition of apoptosis, disruption of cellular microtubule dynamics, and over-activation of the epithelial mesenchymal transition (EMT), are involved in the progression, metastasis, and resistance of colorectal cancer (CRC) to chemotherapy. Therefore, the design of a molecule that can target these pathways could be an effective strategy to reverse CRC progression and metastasis. In this study, twelve novel silybin derivatives, HM015a-HM015k (15a−15k) and compound 17, were screened for cytotoxicity in CRC cell lines. Compounds HM015j and HM015k (15k and 15j) significantly decreased cell proliferation, inhibited colony formation, and produced cell cycle arrest in CRC cells. Furthermore, 15k significantly induced the formation of reactive oxygen species and apoptosis. It induced the cleavage of the intrinsic apoptotic protein (Bax p21) to its more efficacious fragment, p18. Compound 15k also inhibited tubulin expression and disrupted its structure. Compound 15k significantly decreased metastatic LOVO cell migration and invasion. Furthermore, 15k reversed mesenchymal morphology in HCT116 and LOVO cells. Additionally, 15k significantly inhibited the expression of the mesenchymal marker N-cadherin and upregulated the expression of the epithelial marker, E-cadherin. Compound 15k inhibited the expression of key proteins known to induce EMT (i.e., DVL3, β-catenin, c-Myc) and upregulated the anti-metastatic protein, cyclin B1. Overall, in vitro, 15k significantly inhibited CRC progression and metastasis by inhibiting apoptosis, tubulin activity and the EMT pathways. Overall, these data suggest that compound 15k should be tested in vivo in a CRC animal model for further development.

Mechanisms of the anti-tumor activity of Methyl 2-(-5-fluoro-2-hydroxyphenyl)-1 H-benzo[d]imidazole-5-carboxylate against breast cancer in vitro and in vivo

Microtubule Targeting Agents (MTAs) induce cell death through mitotic arrest, preferentially affecting rapidly dividing cancer cells over slowly proliferating normal cells. Previously, we showed that Methyl 2-(-5-fluoro-2-hydroxyphenyl)-1H-benzo[d]imidazole-5-carboxylate (MBIC) acts as a potential MTA. In this study, we demonstrated that MBIC exhibits greater toxicity towards non-aggressive breast cancer cell-line, MCF-7 (IC50 = 0.73 ± 0.0 μM) compared to normal fibroblast cell-line, L-cells (IC50 = 59.6 ± 2.5 μM). The IC50 of MBIC against the aggressive breast cancer cell-line, MDA-MB-231 was 20.4 ± 0.2 μM. We hypothesized that the relatively high resistance of MDA-MB-231 cells to MBIC is associated with p53 mutation. We investigated p53 and three of its downstream proteins: survivin, cyclin dependent kinase (Cdk1) and cyclin B1. Following treatment with MBIC, survivin co-immunoprecipitated with caspases with higher affinity in MDA-MB-231 compared to MCF-7 cells. Furthermore, silencing survivin caused a 4.5-fold increase in sensitivity of MDA-MB-231 cells to MBIC (IC50 = 4.4 ± 0.3). In addition, 4 weeks of MBIC administration in MDA-MB-231 cells inoculated BALB/c nude mice resulted in 79.7% reduction of tumor volume compared to the untreated group with no severe sign of toxicity. Our results demonstrated MBIC has multiple anti-tumor actions and could be a potential drug in breast cancer therapy.

An auxin–tyrosine derivative based biocompatible supergelator: a template for fabrication of nanoparticles for sustained release of model drugs

This report reveals the supergelating ability of an auxin-tyrosine derivative based biocompatible hydrogel in drug delivery.

A novel benzimidazole derivative, MBIC inhibits tumor growth and promotes apoptosis via activation of ROS-dependent JNK signaling pathway in hepatocellular carcinoma

A prior screening programme carried out using MTT assay by our group identified a series of novel benzimidazole derivatives, among which Methyl 2-(5-fluoro-2-hydroxyphenyl)-1H- benzo[d]imidazole-5-carboxylate (MBIC) showed highest anticancer efficacy compared to that of chemotherapeutic agent, cisplatin. In the present study, we found that MBIC inhibited cell viability in different hepatocellular carcinoma (HCC) cell lines without exerting significant cytotoxic effects on normal liver cells. Annexin V-FITC/PI flow cytometry analysis and Western blotting results indicated that MBIC can induce apoptosis in HCC cells, which was found to be mediated through mitochondria associated proteins ultimately leading to the activation of caspase-3. The exposure to MBIC also resulted in remarkable impairment of HCC cell migration and invasion. In addition, treatment with MBIC led to a rapid generation of reactive oxygen species (ROS) and substantial activation of c-Jun-N-terminal kinase (JNK). The depletion of ROS by N-Acetyl cysteine (NAC) partially blocked MBIC-induced apoptosis and JNK activation in HCC cells. Finally, MBIC significantly inhibited tumor growth at a dose of 25 mg/kg in an orthotopic HCC mouse model. Taken together, these results demonstrate that MBIC may inhibit cell proliferation via ROS-mediated activation of the JNK signaling cascade in HCC cells.

Novel quinolone chalcones targeting colchicine-binding pocket kill multidrug-resistant cancer cells by inhibiting tubulin activity and MRP1 function

Agents targeting colchicine-binding pocket usually show a minimal drug-resistance issue, albeit often associated with high toxicity. Chalcone-based compounds, which may bind to colchicine-binding site, are found in many edible fruits, suggesting that they can be effective drugs with less toxicity. Therefore, we synthesized and examined 24 quinolone chalcone compounds, from which we identified ((E)-3-(3-(2-Methoxyphenyl)-3-oxoprop-1-enyl) quinolin-2(1H)-one) (CTR-17) and ((E)-6-Methoxy-3-(3-(2-methoxyphenyl)-3-oxoprop-1-enyl) quinolin-2(1H)-one) (CTR-20) as promising leads. In particular, CTR-20 was effective against 65 different cancer cell lines originated from 12 different tissues, largely in a cancer cell-specific manner. We found that both CTR-17 and CTR-20 reversibly bind to the colchicine-binding pocket on β-tubulin. Interestingly however, both the CTRs were highly effective against multidrug-resistant cancer cells while colchicine, paclitaxel and vinblastine were not. Our study with CTR-20 showed that it overcomes multidrug-resistance through its ability to impede MRP1 function while maintaining strong inhibition against microtubule activity. Data from mice engrafted with the MDA-MB-231 triple-negative breast cancer cells showed that both CTR-17 and CTR-20 possess strong anticancer activity, alone or in combination with paclitaxel, without causing any notable side effects. Together, our data demonstrates that both the CTRs can be effective and safe drugs against many different cancers, especially against multidrug-resistant tumors.

HM015k, a Novel Silybin Derivative, Multi-Targets Metastatic Ovarian Cancer Cells and Is Safe in Zebrafish Toxicity Studies

This study was designed to determine the in vitro mechanisms by which the novel silybin derivative, (E)-3-(3-(benzyloxy) phenyl)-1-(4-hydroxyphenyl)prop-2-en-1-one (HM015k or 15k), produces its anticancer efficacy in ovarian cancer cells. Compound 15k induced apoptosis in ovarian cancer cells in a time-dependent manner by significantly upregulating the expression of Bax and Bak and downregulating the expression of Bcl-2. Interestingly, 15k induced the cleavage of Bax p21 into its more efficacious cleaved form, Bax p18. In addition, caspase 3 and caspase 9 were cleaved to their active forms, inducing the cleavage of poly ADP ribose polymerase (PARP) and β-catenin. Furthermore, in OV2008 cells, 15k induced significant cleavage in nuclear β-catenin to primarily inactive fragments of lower molecular weight. Furthermore, 15k reversed the metastatic potential of OV2008 cells by inhibiting their migration and invasiveness. The mesenchymal phenotype in OV2008 was reversed by 15k, causing cells to be rounder with epithelial-like phenotypes. The 15k-induced reversal was further confirmed by significant upregulation of the E-cadherin expression, an epithelial marker, while N-cadherin, a mesenchymal marker, was downregulated in OV2008 cells. Compound 15k inhibited the expression of the oncogenic c-Myc protein, downregulated proteins DVL3 and DVL2 and significantly upregulated cyclin B1. Also, 15k significantly downregulated the expression levels of ABCG2 and ABCB1 transporters in resistant ABCG2 overexpressing H460/MX20 and resistant ABCB1 overexpressing MDCK/MDR1 cells, respectively. Finally, 15k was safe in zebrafish in vivo model at concentrations up to 10 μM and induced no major toxicities in cardiac, morphology and swimming position parameters. Overall, 15k is a multi-targeted inhibitor with efficacy against metastatic and resistant ovarian cancer. Future in vivo studies will be conducted to determine the efficacy of 15k in tumor-bearing animals.

Thienopyrimidine derivatives exert their anticancer efficacy via apoptosis induction, oxidative stress and mitotic catastrophe

In this study, a series of 13 structural variants of thieno[2,3d]pyrimidine derivatives (6a-6m) were synthesized and screened for cytotoxicity in a panel of colorectal, ovarian, and brain cancer cell lines. The selectivity of the compounds was assessed by determining the cytotoxicity in normal epithelial cell line (CHO). The most potent compound, 6j, was efficacious (with IC₅₀ range of 0.6-1.2 μM) in colon (HCT116 and HCT15), brain (LN-229 and GBM-10) and ovarian (A2780 and OV2008) cancer cell lines. In contrast, in the normal cell line (CHO), the IC₅₀ values for 6j were 14 ± 1.3 μM. Compound 6j significantly inhibited the clonogenic potential of HCT116, OV2008 and A2780 cell lines in concentration - dependent (0.5-4 μM) manner. Also, 6j induced 1) formation of reactive oxygen species; 2) apoptosis and 3) mitotic catastrophe in HCT116 and OV2008 cells (IC₅₀ = 0.5-2 μM). Furthermore, apoptosis was the predominant mechanism of death in A2780 cells. The cytotoxicity of 6j in wild type HCT116 cells was similar to that in HCT116 cells lacking the apoptotic genes for Bax, Bak, or Bak and Bax, indicating that 6j induces mitotic catastrophe as alternative mechanism of death when when certain apoptotic proteins are absent. In summary, this study has identified a lead molecule, 6j, that selectively induces oxidative stress, apoptosis and mitotic catastrophe in specific cancer (colon and ovarian) cell lines.

Abstract 1191: The dopamine (DA) D3 receptor antagonists (PG01037, NGB2904, SB-277011A, and U99194) significantly attenuate ABCG2-mediated multidrug resistance

ATP-binding family G2 (ABCG2) transporters are known to produce multidrug resistance (MDR) and limit successful cancer chemotherapy. Using molecular modeling, we obtained data indicating that highly potent and selective dopamine (DA) D3 receptor antagonists had significant docking scores for the active site of the ABCG2 transporter. In this in vitro study, we determined the effect of the D3 receptor antagonists (PG01037, NGB2904, SB-277011A, and U99194) on MDR resulting from the overexpression of ABCG2 transporters. The D3 receptor antagonists alone did not significantly affect the viability of HEK293/ABCG2, H460/MX-20, S1-M1-80 or A549-MX-10 cells, which overexpress ABCG2 transporters. However, the D3 receptor antagonists (PG01037, NGB2904, SB-277011A, and U99194) significantly increased the efficacy of the anticancer drugs mitoxantrone and doxorubicin in the above mentioned cell lines. Efflux studies indicated that both PG01037 and NGB2904 significantly decreased the efflux of rhodamine 123 from H460-MX20 cells. Interestingly, PG01037 and NGB2904 significantly decreased the expression levels of the ABCG2 protein levels as shown by immunocytochemical and Western blot analysis. This suggests that D3 antagonists inhibit both function and expression of ABCG2 transporters at relevant non-toxic concentrations. In conclusion, our in vitro results indicate that PG01037, NGB2904, SB-277011A, and U99194 reverse resistance to mitoxantrone and doxorubicin mediated by overexpression of ABCG2 transporters. Further mechanistic and animal studies are warranted to establish the clinical use of D3 receptor antagonists in reversing ABCG2-mediated MDR.

Citation Format: Noor Hussein, Haneen Amawi, Charles R. Ashby, Karthikeyan Chandrabose, Roopali Mittal, Ryann Christman, Piyush Trivedi, Amit Tiwari. The dopamine (DA) D3 receptor antagonists (PG01037, NGB2904, SB-277011A, and U99194) significantly attenuate ABCG2-mediated multidrug resistance [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 1191. doi:10.1158/1538-7445.AM2017-1191

Abstract 2238: Novel sylibin analogues target ovarian cancer EMT-Wnt/β-catenin resistance pathways

Ovarian cancer (OC) is one of most lethal malignancies in woman reproductive tract. The OC diagnosed in advanced stage (III-IV) patients is highly aggressive and relapses back in over 80% patient after initial response to chemotherapy. Currently used chemotherapies are limited due to significant adverse/toxic effects, a narrow therapeutic index, and development of multidrug resistance mediated by the epithelial-to-mesenchymal transition (EMT) and cancer cell membrane efflux transporters. It is presumed that an ideal anti-OC drug that has diverse mechanisms, would inhibit several key cell-survival signaling and resistance pathways when combined with conventional chemotherapy (paclitaxel and cisplatin). Silybin, a polyphenolic flavonoid, has previously shown to inhibit metastasis by inhibition of EMT pathways and bypass other drug resistance factors i.e. efflux transporters in ovarian cancer both in vitro and in vivo. However, clinical use of silybin is limited due to their poor absorption and low bioavailability and poor potency. To overcome this, we designed and synthesized 11 silybin derivatives using molecular modeling, computer aided drug design, structure activity relationship, natural product lead optimization and ring disjunction approaches. In our preliminary findings, we found the lead molecule (15k) to have a cytotoxicity (IC50&lt1µM) with potency more than 200-fold compared to silybin (IC50~150µM). The 15k was found to be around 10-fold selective in OC cells (OV2008, A2780) compared to normal ovarian cells. Additionally, compared to other cancer cells belonging to prostate, breast, lung, 15k was (3-6)-fold selective in OC cells (OV2008, A2780). The 15k produced synergistic activity and potentiated the cytotoxic effects of platinum (cisplatin), anthracyclines (doxorubicin) and taxane (paclitaxel) anticancer agents. While 15k also reversed the drug resistance mediated by ABC-efflux transporters to paclitaxel and doxorubicin. Mechanistically, the cytotoxic effect of lead compound 15k, as determined by using molecular biology assays, was found to be due to inhibition of apoptosis, tubulin inhibition, and inhibition of stemness pathways (Wnt-β-catenin-EMT). The 15k had significant anti-metastatic effects as shown by their inhibition of migration and invasion potential on OC cells. In silico findings suggest that pharmacokinetic [PK] profiles of these compounds are favorable compared to silybin. Further in vivo PK/pharmacodynamic studies are underway to establish the clinical use of lead molecule in advanced metastasized, drug resistant OC patients.

Citation Format: Haneen A. Amawi, Noor Hussein, Aubry Fetcenkoa, Rawan Alnafisah, Karthikeyan Chandrabose, Elangovan Manivannan, Piyush Trivedi, Amit K. Tiwari. Novel sylibin analogues target ovarian cancer EMT-Wnt/β-catenin resistance pathways [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 2238. doi:10.1158/1538-7445.AM2017-2238

Advances in siRNA delivery in cancer therapy

RNA interference (RNAi)-based therapeutic approaches are under vibrant scrutinisation to seek cancer cure. siRNA suppress expression of the carcinogenic genes by targeting the mRNA expression. However, in vivo systemic siRNA therapy is hampered by the barriers such as poor cellular uptake, instability under physiological conditions, off-target effects and possible immunogenicity. To overcome these challenges, systemic siRNA therapy warrants the development of clinically suitable, safe, and effective drug delivery systems. Herein, we review the barriers, potential siRNA drug delivery systems, and application of siRNA in clinical trials for cancer therapy. Further research is required to harness the full potential of siRNA as a cancer therapeutic.