Structure-based virtual screening of novel tubulin inhibitors and their characterization as anti-mitotic agents

Optimization of RNA Pepper Sensors for the Detection of Arbitrary RNA Targets

The development of fluorescent light-up RNA aptamers (FLAPs) has paved the way for the creation of sensors to track RNA in live cells. A major challenge with FLAP sensors is their brightness and limited signal-to-background ratio both in vivo and in vitro. To address this, we develop sensors using the Pepper aptamer, which exhibits superior brightness and photostability when compared to other FLAPs. The sensors are designed to fold into a low fluorescence conformation and to switch to a high fluorescence conformation through toehold or loop-mediated interactions with their RNA target. Our sensors detect RNA targets as short as 20 nucleotides in length with a wide dynamic range over 300-fold in vitro, and we describe strategies for optimizing the sensor's performance for any given RNA target. To demonstrate the versatility of our design approach, we generated Pepper sensors for a range of specific, biologically relevant RNA sequences. Our design and optimization strategies are portable to other FLAPs and offer a promising foundation for future development of RNA sensors with high specificity and sensitivity for detecting RNA biomarkers with multiple applications.

Dihydroazolopyrimidines: Past, Present and Perspectives in Synthesis, Green Chemistry and Drug Discovery

Dihydroazolopyrimidines are an important class of heterocycles that are isosteric to natural purines and are therefore of great interest primarily as drug-like molecules. In contrast to the heteroaromatic analogs, synthetic approaches to these compounds were developed much later, and their chemical properties and biological activity have not been studied in detail until recently. In the review, different ways to build dihydroazolopyrimidine systems from different building blocks are described - via the initial formation of a partially hydrogenated pyrimidine ring or an azole ring, as well as a one-pot assembly of azole and azine fragments. Special attention is given to modern approaches: multicomponent reactions, green chemistry, and the use of non-classical activation methods. Information on the chemical properties of dihydroazolopyrimidines and the prospects for their use in the design of drugs of various profiles are also summarized in this review.

Unraveling the molecular crosstalk and immune landscape between COVID-19 infections and ischemic heart failure comorbidity: New insights into diagnostic biomarkers and therapeutic approaches

BACKGROUND

Coronavirus disease 2019 (COVID-19), resulting from severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), remains a persistent global health concern. Evidence has highlighted a significant association between COVID-19 and ischemic heart failure (IHF), contributing to disease progression and increased mortality. This study identified diagnostic biomarkers for these comorbidities and elucidated disease progression's molecular mechanisms.

METHODS

We retrieved differentially expressed gene (DEG) data for COVID-19 and IHF from publicly available microarray and RNA-Seq datasets to investigate the underlying mechanisms and potential pathways associated with the co-occurrence of COVID-19 and IHF. By intersecting the results from the two diseases, we obtained diagnostic biomarkers using SVM-RFE and LASSO algorithms. Animal experiments and immunological analyses were conducted to help understand the association between SARS-CoV-2 and IHF in patients, enabling early diagnosis of disease progression. Finally, we analyzed the regulatory network of critical genes and identified potential drug compounds that could target the genetic links identified in our study.

RESULTS

1974 common DEGs were identified between COVID-19 and IHF, contributing to disease progression and potential cancer risk by participating in immune and cancer-related pathways. In addition, we identified six hub genes (VDAC3, EIF2AK2, CHMP5, FTL, VPS4A, and CHMP4B) associated with the co-morbidity, and their diagnostic potential was confirmed through validation using relevant datasets and a mouse model. Functional enrichment analysis and examination of immune cell infiltration revealed immune dysregulation after disease progression. The comorbid hub genes exhibited outstanding immunomodulatory capacities. We also constructed regulatory networks tightly linked to both disorders, including transcription factors (TFs), miRNAs, and genes at both transcriptional and post-transcriptional levels. Finally, we identified 92 potential drug candidates to enhance the precision of anti-comorbidity treatment strategies.

CONCLUSION

Our study reveals a shared pathogenesis between COVID-19 and IHF, demonstrating that their coexistence exacerbates disease severity. By identifying and consolidating hub genes as pivotal diagnostic biomarkers for COVID-19 and IHF comorbidity, we have made significant advancements in understanding the underlying mechanisms of these conditions. Moreover, our study highlights dysregulated immunity and increased cancer risk in the advanced stages of disease progression. These findings offer novel perspectives for diagnosing and treating IHF progression during SARS-CoV-2 infection.

Triazole-fused pyrimidines in target-based anticancer drug discovery

In recent decades, the development of targeted drugs has featured prominently in the treatment of cancer, which is among the major causes of mortality globally. Triazole-fused pyrimidines, a widely-used class of heterocycles in medicinal chemistry, have attracted considerable interest as potential anticancer agents that target various cancer-associated targets in recent years, demonstrating them as valuable templates for discovering novel anticancer candidates. The current review concentrates on the latest advancements of triazole-pyrimidines as target-based anticancer agents, including works published between 2007 and the present (2007-2022). The structure-activity relationships (SARs) and multiple pathways are also reviewed to shed light on the development of more effective and biotargeted anticancer candidates.

The oncogenic role of tubulin alpha-1c chain in human tumours

Tubulin alpha-1c chain (TUBA1C), a subtype of α-tubulin, has been shown to be involved in cell proliferation and cell cycle progression in several cancers and to influence cancer development and prognosis. However, a pancancer analysis of TUBA1C to reveal its immunological and prognostic roles has not been performed. In this study, we first downloaded raw data on TUBA1C expression in cancers from The Cancer Genome Atlas (TCGA) database and multiple other databases and analysed these data with R software to investigate the prognostic and immunological value of TUBA1C in cancers. Immunohistochemical analysis was performed in gliomas to further validate our findings. Overall, TUBA1C was overexpressed in most cancers, and overexpression of TUBA1C was linked to poor prognosis and higher tumour grade in patients. In addition, TUBA1C expression was associated with tumour mutation burden (TMB), microsatellite instability (MSI), the tumour microenvironment (TME) and the infiltration of immune cells. TUBA1C was also coexpressed with most immune-related genes and influenced immune-related pathways. Immunohistochemical analysis showed that TUBA1C expression was highest in glioblastoma (GBM) tissues, second highest in low-grade glioma (LGG) tissues and lowest in normal tissues. Our study indicated that TUBA1C might be a biomarker for predicting the immune status and prognosis of cancers, offering new ideas for cancer treatment.

Tubulin-binding peptide RR-171 derived from human umbilical cord serum displays antitumor activity against hepatocellular carcinoma via inducing apoptosis and activating the NF-kappa B pathway

Objectives

Hepatocellular carcinoma (HCC) still presents a high incidence of malignant tumours with poor prognosis. There is an urgent need for new therapeutic agents with high specificity, low toxicity and favourable solubility for the clinical treatment of HCC.

Materials and Methods

The bioactivity of human umbilical cord serum was investigated by proteomics biotechnology and a primitive peptide with certain biological activity was identified. The antitumour effect of RR‐171 was detected by cell viability assay in vitro, and determined by subcutaneous xenograft models assay and miniPDX assay in vivo. Pull‐down experiments were conducted to identify the potential targeting proteins of RR‐171. Immunofluorescence assay and tubulin polymerization assay were conducted to explore the relationship between RR‐171 and α‐tubulin. Fluorescence imaging in xenograft models was used to explore the biodistribution of RR‐171 in vivo. A phosphospecific protein microarray was performed to uncover the underlying signalling pathway by which RR‐171 induces tumour cell death.

Results

The results indicated that RR‐171 could be effective in the treatment of HCC in vivo and in vitro. RR‐171 could aggregate significantly in solid tumours and had no obvious systemic toxicity in vivo. RR‐171 could interact with α‐tubulin and activate the NF‐Kappa B pathway in HCC cells.

Conclusions

Taken together, RR‐171 exhibited significant antitumour activity against HCC in vivo and in vitro and could potentially be used in the clinical application of HCC.

Crocodylus porosus Sera a Potential Source to Identify Novel Epigenetic Targets: In Silico Analysis

We have previously found that sera from Crocodylus porosus contain anticancer agents and the treatment of MCF7 cells with this serum resulted in the differential expression of 51 genes. The purpose of this study was to use in silico analysis to identify genes that might be epigenetically modulated in cells treated with crocodile serum and to understand the role of potential genes as novel candidates with epigenetic therapeutic potential. The findings report five proto-oncogenes (TUBA1B, SLC2A1, PGK1, CCND1, and NCAPD2) and two tumor suppressor genes (RPLP2, RPL37) as novel therapeutic targets. Furthermore, we present a comprehensive overview of relevant studies on epigenetic regulation of these genes along with an insight into their clinical implications. Therefore, elucidating the molecules present in the serum and gut bacteria of reptiles such as crocodiles may offer insights into the role of these genes on longevity, health, disease, and life expectancy.

Fused pyrrolo-pyridines and pyrrolo-(iso)quinoline as anticancer agents

This work emphasizes the synthesis strategies and antiproliferative related properties of fused pyrrolo-pyridine (including indolizine and azaindoles) and pyrrolo-(iso)quinoline derivatives recently reported in literature.

tubulin alpha 1c promotes aerobic glycolysis and cell growth through upregulation of yes association protein expression in breast cancer

Tubulin alpha 1c (TUBA1C) as a member of α-tubulin was identified to take part in the occurrence and development of hepatocellular carcinoma and pancreatic cancer. Using the bioinformatics, we noticed that TUBA1C level was also increased in breast cancer was also demonstrated. Here, we explored TUBA1 role in modulation of breast cancer cell aerobic glycolysis, growth and migration and explored whether yes association protein (YAP) was involved. Fifty-five matched breast cancer tissues and the para-carcinoma normal tissues were included in this study and used to verify TUBA1C expression using quantitative reverse transcription-PCR and western blotting. ATP level, lactate secretion and glucose consumption were used to assess aerobic glycolysis. Cell growth, invasion, migration and tumorigenesis were detected using cell count kit-8, transwell, wound healing and animal assays. TUBA1 was upregulated in breast cancer, which associated with advanced primary tumor, lymph node, metastasis stage and tumor size. Silencing of TUBA1C with sh-TUBA1C infection led to significant inhibitions in ATP level, lactate secretion, glucose consumption, cell growth, migration, invasion and tumorigenesis, as well as declined YAP expression, while TUBA1C overexpression induced a opposite result. And, the above tendencies induced by TUBA1C downregulation were reversed by YAP overexpression. This study revealed that TUBA1C was overexpressed in breast cancer and promoted aerobic glycolysis and cell growth through upregulation of YAP expression.

Biological Activity of Triazolopyrimidine Copper(II) Complexes Modulated by an Auxiliary N-N-Chelating Heterocycle Ligands

Novel complexes of type [Cu(N-N)(dmtp)2(OH2)](ClO4)2·dmtp ((1) N-N: 2,2'-bipyridine; (2) L: 1,10-phenantroline and dmtp: 5,7-dimethyl-1,2,4-triazolo[1,5-a]pyrimidine) were designed in order to obtain biologically active compounds. Complexes were characterized as mononuclear species that crystallized in the space group P-1 of the triclinic system with a square pyramidal geometry around the copper (II). In addition to the antiproliferative effect on murine melanoma B16 cells, complex (1) exhibited low toxicity on normal BJ cells and did not affect membrane integrity. Complex (2) proved to be a more potent antimicrobial in comparison with (1), but both compounds were more active in comparison with dmtp-both against planktonic cells and biofilms. A stronger antimicrobial and antibiofilm effect was noticed against the Gram-positive strains, including methicillin-resistant Staphylococcus aureus (MRSA). Both electron paramagnetic resonance (EPR) and Saccharomyces cerevisiae studies indicated that the complexes were scavengers rather than reactive oxygen species promoters. Their DNA intercalating capacity was evidenced by modifications in both absorption and fluorescence spectra. Furthermore, both complexes exhibited nuclease-like activity, which increased in the presence of hydrogen peroxide.

TUBA1C is a Prognostic Marker in Low-grade Glioma and Correlates with Immune Cell Infiltration in the Tumor Microenvironment

TUBA1C, a microtubule component, contributes to the development of several cancers. Our purpose was to study the expression of TUBA1C, its potential prognostic value, and its effects on the infiltration of immune cells of low-grade glioma (LGG). Through applying multiple bioinformatics analyses, we extracted and analyzed datasets from TCGA, TIMER, GTEx, GEPIA, and HPA to investigate the potential oncogenic mechanisms of TUBA1C, including the correlation between TUBA1C and prognosis, immune-checkpoints, tumor microenvironment (TME), and infiltration of immune cells in LGG. GO functional annotations and KEGG pathway analyses were further applied to investigate the potential action of TUBA1C in LGG. We revealed that the mRNA levels of TUBA1C were increased in LGG tumor tissues than in normal tissues. Additionally, TUBA1C was up-regulated in the grade III of LGG than in grade II. Moreover, we found that TUBA1C may be an independent prognostic factor of LGG, and high TUBA1C expression correlated to a poor prognosis of LGG. TUBA1C expression was positively associated with the infiltration of B cells, CD8 T+ cells, CD4⁺ T cells, macrophages, dendritic cells, and neutrophils. TUBA1C was also verified to be co-expressed with immune-related genes and immune-checkpoints. GO and KEGG pathway analyses indicated that TUBA1C may potentially regulate the pathogenesis of LGG through immune-related pathways, including chemokine pathway; JAK-STAT pathway; natural killer cell mediated cytotoxicity; T cell receptor pathway; leukocyte migration; negative regulation of immune system process; regulation of lymphocyte activation; T cell activation and other pathways. In conclusion, TUBA1C expression is increased in LGG and high TUAB1C expression is related to a poor prognosis. TUBA1C may influence tumor development by regulating the tumor-infiltrating cells in the TME. TUBA1C may be a potential target for immunotherapy.

Comprehensive strategies of machine-learning-based quantitative structure-activity relationship models

Early quantitative structure-activity relationship (QSAR) technologies have unsatisfactory versatility and accuracy in fields such as drug discovery because they are based on traditional machine learning and interpretive expert features. The development of Big Data and deep learning technologies significantly improve the processing of unstructured data and unleash the great potential of QSAR. Here we discuss the integration of wet experiments (which provide experimental data and reliable verification), molecular dynamics simulation (which provides mechanistic interpretation at the atomic/molecular levels), and machine learning (including deep learning) techniques to improve QSAR models. We first review the history of traditional QSAR and point out its problems. We then propose a better QSAR model characterized by a new iterative framework to integrate machine learning with disparate data input. Finally, we discuss the application of QSAR and machine learning to many practical research fields, including drug development and clinical trials.

[3 + 2]-Annulation of pyridinium ylides with 1-chloro-2-nitrostyrenes unveils a tubulin polymerization inhibitor

Indolizines and pyrazolo[1,5-a]pyridines were prepared via [3 + 2]-cycloaddition of pyridinium ylides to 1-chloro-2-nitrostyrenes. The synthesized molecules were evaluated for antiproliferative activities against a BE(2)-C neuroblastoma cell line with several compounds decreasing the viability of cancer cells. Indolizine 9db showed higher potency than that of all-trans-retinoic acid, an approved cancer drug. Mechanistically, it was found to inhibit tubulin polymerization and it is thus proposed that the discovered chemistry can be exploited for the development of novel microtubule-targeting anticancer agents.

Prognostic biomarker TUBA1C is correlated to immune cell infiltration in the tumor microenvironment of lung adenocarcinoma

BACKGROUND

TUBA1C is a microtubule component that is involved in a variety of cancers. Our main objective was to investigate TUBA1C expression, its prognostic value, its potential biological functions, and its impact on the immune system of patients with lung adenocarcinoma (LUAD).

METHODS

The Cancer Genome Atlas (TCGA), Gene Expression Profiling Interactive Analysis (GEPIA) and Immunohistochemistry Analysis were used to analyze TUBA1C expression, its clinicopathology, overall survival (OS), and disease-free survival (DFS) in LUAD patients. We also determined the correlation between TUBA1C and tumor-infiltrating immune cells (TIICs) by using CIBERSORT and GEPIA databases. To determine the expression of TUBA1C in LUAD, we analyzed a collection of immune infiltration levels and cumulative survival of LUAD tissues in TIMER database. By using UALCAN, STRING, and GeneMANIA databases, we investigated the protein-coding genes related to TUBA1C and its co-expression genes in LUAD tissues. Gene set enrichment analysis (GSEA) was performed by using the TCGA dataset.

RESULTS

The mRNA and the protein expression of TUBA1C were found to be up-regulated in LUAD tissues. The univariate analysis indicated that an increased expression of TUBA1C was significantly correlated to the following parameters: age, stage, and lymph node metastasis. An over-expression of TUBA1C was associated with a poor prognosis of LUAD. In TIMER and CIBERSORT databases, we found that TUBA1C is correlated with 13 types of TIICs: activated B cell, activated CD4 T cell, central memory CD4 T cell, effector memory CD8 T cell, eosinophils, immature B cell, gamma-delta T cell, immature dendritic cell, mast cell, memory B cell, natural killer T cell, regulatory T cell, and type 2T helper cell. By performing GSEA, we found that TUBA1C is closely correlated to cell cycle, p53 signaling pathway, glycolysis, and gluconeogenesis.

CONCLUSIONS

Our findings indicate that TUBA1C is associated with TIICs in tumor microenvironment. Therefore, it serves as a novel prognostic biomarker and a target for future treatment methods of LUAD.

The Expression and Potential Role of Tubulin Alpha 1b in Wilms' Tumor

We explored the difference in expression of tubulin alpha 1b (TUBA1B) between Wilms' tumor (WT) and normal tissues (NT) from in-house patients and databases, to determine TUBA1B expression in WT and the predictive pathways of coexpressed genes. In-house RNA-sequencing data were performed with WT and NT from three patients from our institute. Other four RNA-sequencing and microarray data were also downloaded from multiple public databases. The TUBA1B expression between WT and NT was analyzed by Student's t-test and meta-analysis. The correlation between the expression of TUBA1B and other genes in each study was analyzed. Genes with p < 0.05 and r > 0.5 were considered as the coexpressing genes of TUBA1B. Overlapping the coexpressed genes of the five studies, including three in-house patients (3 WT vs. 3 NT), GTEx-TARGET (126 WT vs. 51 NT), GSE2172 (18 WT vs. 3 NT), GSE11024 (27 WT vs. 12 NT), and GSE73209 (32 WT vs. 6 NT), were performed with limma and VennDiagram packages in R software. The website of WEB-based GEne SeT AnaLysis toolkit were used to analyze the gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) functional annotations for the overlapped genes. The results showed that the relative expression of TUBA1B in WT tissues from in-house three patients was 280.0086, 141.7589, and 303.8292 and that in NT was 16.5836, 104.8141, and 12.79 (3 WT vs. 3 NT, p = 0.0285, ROC = 100%, SMD = 2.74). Student's t-test and meta-analysis in all studies revealed that the expression of TUBA1B was upregulated in WT tissues compared to that in NT (p < 0.05, SMD = 2.89, sROC = 0.98). Finally, the research identified the expression of TUBA1B in WT tissues was significantly upregulated than that in NT. The coexpressed genes of TUBA1B were enriched in the pathway of DNA replication, mismatch repair, cell cycle, pathogenic Escherichia coli infection, and spliceosome.

Inhibitory activities of indolizine derivatives: a patent review

INTRODUCTION

Indolizines are structural isomers with indoles. Although several indole-based commercial drugs are available in the market, none of the indolizine-based drugs are available up-to-date. Natural and synthetic indolizines have a wide-range of pharmaceutical importance such as antitumor, antimycobacterial, antagonist, and antiproliferative activities. This prompted us to search and collect all possible data about the pharmacological importance of indolizine to open an avenue to the researchers in exploring more medicinal applications of such biologically important compounds.

AREAS COVERED

The current review article covers the advancements in the biological and pharmacological activities of indolizine-based compounds during the last decade. The covered areas of this work involved anticancer, anti-HIV-1, anti-inflammatory, antimicrobial, anti-tubercular, larvicidal, anti-schizophrenia, CRTh2 antagonist's activities in addition to enzymatic inhibitory activity.

EXPERT OPINION

The discovery of indolizine drugs will be a major breakthrough as compared with their widely available drug-containing indole isosteres. Major work collected here was focused on anticancer, anti-tubercular, anti-inflammatory, and enzymatic inhibitory activities. The SAR study of the reported biologically active indolizines is summarized throughout the review whenever highlighted to the rationale the behavior of inhibitory action. Several indolizines with certain functions provided great enhancement in the therapeutic activities comparing with reference drugs.

Upregulated Expression of TUBA1C Predicts Poor Prognosis and Promotes Oncogenesis in Pancreatic Ductal Adenocarcinoma via Regulating the Cell Cycle

Background: Pancreatic ductal adenocarcinoma (PDAC) is a highly malignant disease and has the worst prognosis and survival rate. TUBA1C is a microtubule component implicated in multiple cancers, however, the clinical significance and biological functions of TUBA1C in the progression of PDAC remain unexplored.

Methods: The Cancer Genome Atlas (TCGA) and Gene Expression Profiling Interactive Analysis (GEPIA) data were employed to detect the TUBA1C mRNA expression and the relation between TUBA1C expression and overall survival (OS) in PDAC. Then, bioinformatic analysis was employed to determine the potential pathway and genes related to TUBA1C. Human pancreatic cancer tissue and adjacent non-tumor tissues samples were detected by immunochemistry (IHC) staining, and the correlation between TUBA1C expression and the clinicopathological features were investigated. Meanwhile, TUBA1C expression in PDAC cell lines was evaluated by western blotting. Furthermore, functional assays including cell viability, apoptosis, cell cycle, transwell assay, wound healing assay, and a xenograft tumor model were performed to determine the oncogenic role of TUBA1C in PDAC, respectively.

Results: TUBA1C was overexpressed in the PDAC tissues and cells. IHC analysis showed that the TUBA1C overexpression was associated with short OS. Bioinformatic analysis indicated that TUBA1C overexpression was mainly associated with cell cycle regulation. The downregulation of TUBA1C significantly suppressed cell proliferation, induced cell apoptosis and cycle arrest, and inhibited invasion and migration in PDAC cells. Furthermore, TUBA1C downregulation also inhibited tumor growth in vivo.

Conclusion: These findings suggested that TUBA1C downregulation suppressed PDAC aggressiveness via cell cycle pathway and that TUBA1C may serve as a potential prognostic marker for PDAC therapy.

Highly Chemoselective, Transition-Metal-Free Transamidation of Unactivated Amides and Direct Amidation of Alkyl Esters by N-C/O-C Cleavage

The amide bond is one of the most fundamental functional groups in chemistry and biology and plays a central role in numerous processes harnessed to streamline the synthesis of key pharmaceutical and industrial molecules. Although the synthesis of amides is one of the most frequently performed reactions by academic and industrial scientists, the direct transamidation of tertiary amides is challenging due to unfavorable kinetic and thermodynamic contributions of the process. Herein, we report the first general, mild, and highly chemoselective method for transamidation of unactivated tertiary amides by a direct acyl N-C bond cleavage with non-nucleophilic amines. This operationally simple method is performed in the absence of transition metals and operates under unusually mild reaction conditions. In this context, we further describe the direct amidation of abundant alkyl esters to afford amide bonds with exquisite selectivity by acyl C-O bond cleavage. The utility of this process is showcased by a broad scope of the method, including various sensitive functional groups, late-stage modification, and the synthesis of drug molecules (>80 examples). Remarkable selectivity toward different functional groups and within different amide and ester electrophiles that is not feasible using existing methods was observed. Extensive experimental and computational studies were conducted to provide insight into the mechanism and the origins of high selectivity. We further present a series of guidelines to predict the reactivity of amides and esters in the synthesis of valuable amide bonds by this user-friendly process. In light of the importance of the amide bond in organic synthesis and major practical advantages of this method, the study opens up new opportunities in the synthesis of pivotal amide bonds in a broad range of chemical contexts.

A small molecule screening to detect potential therapeutic targets in human podocytes

WIDMEIER E, TAN W, AIRIK M, HILDEBRANDT F

A small molecule screening to detect potential therapeutic targets in human podocytes. Am J Physiol Renal Physiol 312: F157-F171, 2017. First published October 19, 2016; doi:10.1152/ajprenal.00386.2016. Steroid-resistant nephrotic syndrome (SRNS) inevitably progresses to end-stage kidney disease, requiring dialysis or transplantation for survival. However, treatment modalities and drug discovery remain limited. Mutations in over 30 genes have been discovered as monogenic causes of SRNS. Most of these genes are predominantly expressed in the glomerular epithelial cell, the podocyte, placing it at the center of the pathogenesis of SRNS. Podocyte migration rate (PMR) represents a relevant intermediate phenotype of disease in monogenic causes of SRNS. We therefore adapted PMR in a high-throughput manner to screen small molecules as potential therapeutic targets for SRNS. We performed a high-throughput drug screening of a National Institutes of Health Clinical Collection (NCC) library (n = 725 compounds) measuring PMR by videomicroscopy. We used the Woundmaker to perform individual 96-well scratch wounds and screened compounds using a quantitative kinetic live cell imaging migration assay using IncuCyte ZOOM technology. Using a normal distribution for the average PMR in wild-type podocytes with a vehicle control (DMSO), we applied a 90% confidence interval to define "distinct" compounds (5% faster/slower PMR) and found that 12 of 725 compounds (at 10 μM) reduced PMR. Clusters of drugs that alter PMR included actin/tubulin modulators such as the azole class of antifungals and antineoplastic vinca-alkaloids. We hereby identify compounds that alter PMR. The PMR assay provides a new avenue to test therapeutics for nephrotic syndrome. Positive results may reveal novel pathways in the study of glomerular diseases such as SRNS.

Studies on indolizines. Evaluation of their biological properties as microtubule-interacting agents and as melanoma targeting compounds

With the aim of investigating new analogues of phenstatin with an indolizin-3-yl unit, in particular as the B-ring, three new series of compounds (6-8, 9-34 and 54) were synthesized and tested for interactions with tubulin polymerization and evaluated for cytotoxicity on an NCI-60 human cancer cell lines panel. The replacement of the 3'-hydroxy-4'-methoxyphenyl B-ring of phenstatin with substituted indolizine unit results in the conservation of both antitubulin and cytotoxic effect. Indolizines 9 and 17 were the most effective in the present study and showed the highest antiproliferative effect on melanoma cell lines MDA-MB-435 (GI50 = 30 nM) and could serve as new lead compounds for the development of anti-cancer therapeutics.

Combretastatin A-4 inspired novel 2-aryl-3-arylamino-imidazo-pyridines/pyrazines as tubulin polymerization inhibitors, antimitotic and anticancer agents

Novel 2-aryl-3-arylamino-imidazo-pyridines/pyrazines that exhibit potent tubulin polymerization inhibition, anticancer activity, anti-migration of cancer cells, chromosomal damage, and apoptosis have been developed.

Increased α-tubulin1b expression indicates poor prognosis and resistance to chemotherapy in hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer deaths worldwide. It is important to understand molecular mechanisms of HCC progression and to develop clinically useful biomarkers for the disease.

AIM

We aimed to investigate the possible involvement of α-tubulin1b (TUBA1B) in HCC pathology.

METHODS

Tissue specimens were obtained from 114 HCC patients during hepatectomy. Immunohistochemistry and western blot analysis were used to detect TUBA1B expression in HCC tissues and cell lines. TUBA1B was knocked down in HCC cells by siRNA transfection. CCK-8 assay and flow cytometry were applied to determine cell proliferation and cell cycle progression, respectively. The efficacy of paclitaxel chemotherapy was evaluated by plate colony formation assay.

RESULTS

TUBA1B was higher expressed in HCC tumor tissues than in adjacent nontumor tissues. TUBA1B and Ki-67 expressions were positively related to each other, and both their expressions were significantly associated with histological grade of HCC patients. Univariate and multivariate survival analyses revealed that TUBA1B was a significant predictor for overall survival of HCC patients. TUBA1B expression was increased in HCC cells during the G1- to S-phase transition. TUBA1B knockout in HCC cells inhibited cell proliferation, and attenuated resistance to paclitaxel.

CONCLUSIONS

Our results indicated that TUBA1B expression was upregulated in HCC tumor tissues and proliferating HCC cells, and an increased TUBA1B expression was associated with poor overall survival and resistance to paclitaxel of HCC patients.

Tubulin-interactive stilbene derivatives as anticancer agents

Microtubules are dynamic polymers that occur in eukaryotic cells and play important roles in cell division, motility, transport and signaling. They form during the process of polymerization of α- and β-tubulin dimers. Tubulin is a significant and heavily researched molecular target for anticancer drugs. Combretastatins are natural cis-stilbenes that exhibit cytotoxic properties in cultured cancer cells in vitro. Combretastatin A-4 (3′-hydroxy-3,4,4′, 5-tetramethoxy-cis-stilbene; CA-4) is a potent cytotoxic cis-stilbene that binds to β-tubulin at the colchicine-binding site and inhibits tubulin polymerization. The prodrug CA-4 phosphate is currently in clinical trials as a chemotherapeutic agent for cancer treatment. Numerous series of stilbene analogs have been studied in search of potent cytotoxic agents with the requisite tubulin-interactive properties. Microtubule-interfering agents include numerous CA-4 and transresveratrol analogs and other synthetic stilbene derivatives. Importantly, these agents are active in both tumor cells and immature endothelial cells of tumor blood vessels, where they inhibit the process of angiogenesis. Recently, computer-aided virtual screening was used to select potent tubulin-interactive compounds. This review covers the role of stilbene derivatives as a class of antitumor agents that act by targeting microtubule assembly dynamics. Additionally, we present the results of molecular modeling of their binding to specific sites on the α- and β-tubulin heterodimer. This has enabled the elucidation of the mechanism of stilbene cytotoxicity and is useful in the design of novel agents with improved anti-mitotic activity. Tubulin-interactive agents are believed to have the potential to play a significant role in the fight against cancer.

Synthesis of novel chromene derivatives of expected antitumor activity

Inhibition of tubulin polymerization is one of the important tactics in cancer therapy. Since 4-aryl-4H-chromene derivatives are found to be microtubule-binding agents via interfering with tubulin polymerization so we decide to concentrate our exploration efforts on the combination of this nucleus with 5-, 6-, and/or 7-memebered heterocyclic moieties in a novel series of compounds to explore the effect that might result from this combination. Ten novel compounds were selected for anticancer screening assay against MCF-7 breast cancer cell line in comparison to colchicine as positive control and most of them showed excellent activity.

Discovery of novel tubulin inhibitors via structure-based hierarchical virtual screening

To discover novel tubulin inhibitors, we performed structure-based virtual screening against the colchicine binding pocket. In combination with a hierarchical docking and scoring procedure, the structural information of an additional subpocket in colchicine site was applied to filter out the undesired docking hits. This strategy automatically resulted in 63 candidates meeting the structural and energetic criteria from a screening library containing approximately 100,000 diverse druglike compounds. Among them, nine molecules were chosen for experimental validation, which all share the similar binding pose and contain an enriched scaffold bearing thiophene core. Encouragingly, five compounds are active in tubulin polymerization assay. The most potent inhibitor, 2-(2-fluorobenzamido)-3-carboxamide-4,5-dimethylthiophene, is structurally distinct to any known colchicine site binders and has higher ligand efficiency than colchicine. On the basis of its predicted binding pose, we systematically probed its binding characteristics by testing series of structural modifications. The obtained structure-activity relationship results are consistent with our binding model, and the inhibition activities of two analogues are improved by 2-fold. We expect that the novel structure discovered in the present study may serve as a starting point for developing tubulin inhibitors with improved efficacy and fewer side effects. We also expect that our hierarchical strategy may be generally applicable in structure-based virtual screening campaigns.