Discovery and biological evaluation of 6-aryl-4-(3,4,5-trimethoxyphenyl)quinoline derivatives with promising antitumor activities as novel colchicine-binding site inhibitors.

Tubulin, as the fundamental unit of microtubules, is a crucial target in the investigation of anticarcinogens. The synthesis and assessment of small-molecule tubulin polymerization inhibitors remains a promising avenue for the development of novel cancer therapeutics. Through an analysis of reported colchicine-binding site inhibitors (CBSIs) and tubulin binding models, a set of 6-aryl-4-(3,4,5-trimethoxyphenyl)quinoline derivatives were meticulously crafted as potential CBSIs. Notably, compound 14u exhibited potent anti-proliferative efficacy, displaying IC50 values ranging from 0.03 to 0.18 µM against three human cancer cell lines (Huh7, MCF-7, and SGC-7901). Mechanistic investigations revealed that compound 14u could disrupt tubulin polymerization, dismantle the microtubule architecture, arrest the cell cycle at G2/M phase, and induce apoptosis in cancer cells. Furthermore, compound 14u demonstrated significant inhibition of tumor proliferation in vivo with no discernible toxicity in the Huh7 orthotopic tumor model mice. Additionally, physicochemical property predictions indicated that compound 14u adhered well to Lipinski's rule of five. These findings collectively suggest that compound 14u holds promise as an antitumor agent targeting the colchicine-binding site on tubulin and warrants further investigation.

Synthesis of New Thiazole-Privileged Chalcones as Tubulin Polymerization Inhibitors with Potential Anticancer Activities.

A series of novel thiazole-based chalcones were evaluated for their anticancer activity as potential tubulin polymerization inhibitors. In vitro anticancer screening for the thiazole derivatives 2a-2p exhibited broad-spectrum antitumor activity against various cancer cell lines particularly Ovar-3 and MDA-MB-468 cells with a GI50 range from 1.55 to 2.95 µΜ, respectively. Compound 2e demonstrated significant inhibition of tubulin polymerization, with an IC50 value of 7.78 µM compared to Combretastatin-A4 (CA-4), with an IC50 value of 4.93 µM. Molecular docking studies of compounds 2e, 2g, and 2h into tubulin further supported these findings, revealing that they bind effectively to the colchicine binding site, mirroring key interactions exhibited by CA-4. Computational predictions suggested favorable oral bioavailability and drug-likeness for these compounds, highlighting their potential for further development as chemotherapeutic agents.

TUBA1C orchestrates the immunosuppressive tumor microenvironment and resistance to immune checkpoint blockade in clear cell renal cell carcinoma.

Background: Clear cell renal cell carcinoma (ccRCC) poses substantial treatment challenges, especially in advanced stages where the efficacy of immune checkpoint blockade (ICB) therapy varies significantly. Elevated expression of the oncogene TUBA1C has been correlated with poor prognosis in various cancers, however, its role in ccRCC is unclear, especially concerning ICB resistance. Methods: Single-cell analysis was used to examine gene expression variations in malignant cells post-ICB therapy. This included investigating TUBA1C expression across different ICB response groups and its relationship with CD274. A general module of action was identified through pan-cancer and pan-tissue analysis. TUBA1C expression and its association with clinical characteristics and prognosis was further validated. Multiple algorithms were employed to explore immune cell infiltration levels, and the DepMap database was utilized to assess gene dependency and mutation status in kidney cancer cell lines. The in silico knockout of TUBA1C was performed using deep learning model, complemented by immunohistochemical assays, clinical cohort and functional assays validations. Results: TUBA1C expression is elevated in malignant cells following ICB therapy and is correlated with ICB resistance in ccRCC. High TUBA1C expression activates PI3K/AKT pathway and is associated with increased infiltration of regulatory T cells and myeloid-derived suppressor cells, which contributes to an immunosuppressive microenvironment in ccRCC. Patients with high TUBA1C expression exhibit a greater tumor mutation burden and increased genetic variation, which causes a worse prognosis. Additionally, TUBA1C dependency and its effects were evident in kidney cancer cell lines, where mutations conferred resistance to anti-PD-L1 therapy. In silico knockout analyses indicated that treatment targeting TUBA1C shifted malignant cells to a state responsive to ICB therapy. Immunohistochemistry, RT-qPCR and clinical cohort validation further confirmed that TUBA1C expression was upregulated and contributed to poorer outcome in ccRCC. Finaly, wound healing and CCK-8 assays demonstrated the potent oncogenic function of TUBA1C. Conclusions: TUBA1C is a pivotal regulator in ccRCC, affecting both disease progression and the effectiveness of ICB therapy by fostering an immunosuppressive microenvironment mediated by the PI3K/AKT pathway. Additionally, TUBA1C holds promise, both as a prognostic biomarker and a therapeutic target, for enhancing responsiveness to ICB.

Tetrahydrocarbazoles incorporating 5-arylidene-4-thiazolinones as potential antileukemia and antilymphoma targeting tyrosine kinase and tubulin polymerase enzymes: Design, synthesis, structural, biological and molecular docking studies.

Finding effective and selective anticancer agents is a top medical priority due to high clinical treatment demand. However, current anticancer agents have serious side effects and resistance development remains a big concern. This creates an urgent need for new multitarget drugs that could solve these problems. Tetrahydrocarbazoles and 5-arylidene-4-thiazolinones have always attracted researchers for their multifaced anticancer activities and the possibility to be easily derivatized. Thereby, herein we report the combination of the two scaffolds to provide compounds 9a-j and 10a-j that were fully characterized and their tautomeric form was confirmed by crystal structure. 9a-j and 10a-j wereassessedfor invitro antiproliferative activityusing SRB assay against a panel of seven human cancer cell lines with doxorubicin as the standard. The results revealed that the cell lines derived from leukemia (Jurkat) and lymphoma (U937) are the most sensitive. Compounds 9d, 10e, 10g, and 10f revealed the highest potency (IC50 = 3.11-11.89 µM) with much lower effects on normal lymphocytes cell line (IC50 > 50 µM). The results show that modifications at 6th position of the THC and the nature of the substituent at the arylidene moiety affect the activity. To exploit the mode of action, 9d, 10e, 10f, and 10g were evaluated as VEGFR-2 and EGFR inhibitors. 10e is the most potent (IC50 0.26 and 0.14 µM) against both enzymes. It also induced G0-G1-phase cell cycle arrest and apoptosis. While 10g exhibited higher potency (IC50 9.95 µM) than vincristine (IC50 15.63 µM) against tubulin. A molecular docking study was carried out to understand the interactions between 10e, 10g and their targets. This study reveals 10e and 10g as possible candidates for developing multitarget anticancer agents against leukemia and lymphoma.

RBN-2397, a PARP7 Inhibitor, Synergizes with Paclitaxel to Inhibit Proliferation and Migration of Ovarian Cancer Cells.

Objectives: Mono(ADP-ribosyl)ation (MARylation), a post translational modification of proteins, is emerging as an important regulator of the biology of cancer cells. PARP7 (TiPARP), a mono (ADP-ribosyl) transferase (MART), MARylates its substrate α-tubulin in ovarian cancer cells, promoting destabilization of microtubules, cell growth, and migration. Recent development of RBN-2397, a potent inhibitor that selectively acts on PARP7, has provided a new tool for exploring the role of PARP7 catalytic activity in biological processes. In this study, we investigated the role of PARP7 catalytic activity in the regulation of ovarian cancer cell biology via MARylation of α-tubulin. Methods: Ovarian cancer cell lines (OVCAR4, OVCAR3) were treated with RBN-2397 and paclitaxel, both separately and in combination. Western blotting and immunoprecipitation confirmed the effects of RBN-2397 on α-tubulin MARylation and stabilization. Cell proliferation and migration were assessed, and α-tubulin stabilization was quantified using immunofluorescent imaging. RNA-sequencing was performed to assess the effects on gene expression changes. Results: RBN-2397 inhibited PARP7 activity, decreasing α-tubulin MARylation, leading to its stabilization, and reducing cancer cell proliferation and migration. The addition of paclitaxel further enhanced these effects, highlighting a synergistic interaction between the two drugs. Mutating the site of PARP7-mediated MARylation on α-tubulin similarly resulted in microtubule stabilization and decreased cell migration in the presence of paclitaxel. Conclusions: This study demonstrates that targeting PARP7 with RBN-2397, particularly in combination with paclitaxel, offers an effective strategy for inhibiting aggressive ovarian cancer cell phenotypes. Our findings underscore the potential of combining PARP7 inhibitors with established chemotherapeutics to enhance treatment efficacy in ovarian cancer.

Unveiling the anti-cancer potentiality of phthalimide-based Analogues targeting tubulin polymerization in MCF-7 cancerous Cells: Rational design, chemical Synthesis, and Biological-coupled Computational investigation.

The present study deals with an anti-cancer investigation of an array of phthalimide-1,2,3-triazole molecular conjugates with various sulfonamide fragments against human breast MCF-7 and prostate PC3 cancer cell lines. The targeted 1,2,3-triazole derivatives 4a-l and 6a-c were synthesized from focused phthalimide-based alkyne precursors using a facile click synthesis approach and were thoroughly characterized using several spectroscopic techniques (IR, 1H, 13C NMR, and elemental analysis). The hybrid click adducts 4b, 4 h, and 6c displayed cytotoxic potency (IC50 values of 1.49, 1.07, and 0.56 µM, respectively) against MCF-7 cells. On the contrary, none of the synthesized compounds showed apparent cytotoxic efficacy for PC3 cells (IC50 ranging from 9.87- >100 µM). As a part of the mechanism analysis, compound 6c demonstrated a potent inhibitory effect (78.3 % inhibition) of tubulin polymerization in vitro with an IC50 value of 6.53 µM. In addition, biological assays showed that compound 6c could prompt apoptotic cell death and induce G2/M cell cycle arrest in MCF-7 cells. Accordingly, compound 6c can be further developed as an anti-breast cancer agent through apoptosis-induction.

A potent Bioorganic azapodophyllotoxin derivative Suppresses tumor Progression in Triple negative breast Cancer: An Insight into its Inhibitory effect on tubulin polymerization and Disruptive effect on microtubule assembly.

Triple negative breast cancer (TNBC) has long been a challenging disease owing to its high aggressive behaviour, poor prognosis and its limited treatment options. The growing demand of new therapeutics against TNBC enables us to examine the therapeutic efficiency of an emerging class of anticancer compounds, azapodophyllotoxin derivative (HTDQ), a nitrogen analogue of podophyllotoxin, using different biochemical, spectroscopic and computational approaches. The anticancer activities of HTDQ are studied by performing MTT assay in a dose depended manner on Triple negative breast cancer cells using MDA-MB-468 and MDA-MB-231 cell lines with IC50 value 937 nM and 1.13 µM respectively while demonstrating minimal effect on normal epithelial cells. The efficacy of HTDQ was further tested in 3D tumour spheroids formed by the human TNBC cell line MDA-MB468 and also the murine MMTV positive TNBC cell line 4 T1. The shrinkage that observed in the tumor spheroid clearly indicates that HTDQ remarkably decreases the growth of tumor spheroid thereby affirming its cytotoxicity. The 2D cell viability assay shows significant morphological alteration that possibly caused by the cytoskeleton disturbances. Hence the binding interaction of HTDQ with cytoskeleton protein tubulin, its effect on tubulin polymerisation as well as depolymerisation of preformed microtubules along with the conformational alternation in the protein itself have been investigated in detail. Moreover, the apoptotic effects of HTDQ have been examined using a range of apoptotic markers. HTDQ-treated cancer cells showed increased expression of cleaved PARP-1 and pro-caspase-3, suggesting activation of the apoptosis process. HTDQ also upregulated pro-apoptotic Bax expression while inhibiting anti-apoptotic Bcl2 expression, supporting its ability to induce apoptosis in cancer cells. Hence the consolidated biochemical and spectroscopic research described herein may provide enormous information to use azapodophyllotoxin as promising anticancer therapeutics for TNBC cells.

Highly Cytotoxic Cryptophycin Derivatives with Modification in Unit D for Conjugation.

Cytotoxic payloads for drug conjugates suitable for directed tumor therapy need to be highly potent and require a functional group for conjugation with the homing device (antibody, peptide, or small molecule). Cryptophycins are cyclodepsipeptides that stand out from the realm of natural products due to their extraordinarily high cytotoxicity. However, the installation of a suitable conjugation handle without compromising the toxicity is highly challenging. The unit D, natively 2-hydroxyisocaproic acid (leucic acid), was envisaged as a promising attachment site based on structural information from X-ray analysis. A versatile, scalable and efficient synthetic route towards conjugable cryptophycins with modification in unit D was developed and an array of new cryptophycin analogues was synthesized. Several derivatives, especially those containing lipophilic groups with low steric demand such as alkylated amino groups, exhibit low picomolar cytotoxicity often combined with efficacy against multidrug-resistant tumor cells. The newly established cryptophycin analogues comprise a broad range of relevant functional groups used as conjugation handles, among them amino, hydroxy, carboxy, as well as sulfur-containing derivatives. X-ray crystallographic analysis of a tubulin-bound cryptophycin together with quantitative structure activity relationship manifested rationales for the synthesis of most potent cryptophycin derivatives and further confirmed the suitability of modifications in unit D.

Symmetrical 2,7-disubstituted 9H-fluoren-9-one as a novel and promising scaffold for selective targeting of SIRT2.

Sirtuin 2 (SIRT2) belongs to the family of silent information regulators (sirtuins), which comprises nicotinamide adenine dinucleotide (NAD+)-dependent protein lysine deacetylases. With a distribution across numerous tissues and organs of the human body, SIRT2 is involved in a wide range of physiological and pathological processes, such as regulating the cell cycle, energy metabolism, DNA repair, and tumorigenesis. Aberrant expression of SIRT2 has been closely associated with particular etiologies of human diseases, positioning SIRT2 as a promising therapeutic target. Herein, we detail the design overview and findings of novel symmetrical 2,7-disubstituted 9H-fluoren-9-one derivatives targeting SIRT2. SG3 displayed the most potent SIRT2-selective inhibitory profile, with an IC50 value of 1.95 µ M $\mu {\rm{M}}$ , and reduced the cell viability of human breast cancer MCF-7 cells accompanied by hyperacetylation of α-tubulin. Finally, molecular docking, molecular dynamics simulations, and binding free energy calculations using molecular mechanics/generalized born surface area method were performed to verify the binding ability of SG3 to SIRT2. Taken together, these results could enhance our understanding of the structural elements necessary for inhibiting SIRT2 and shed light on the mechanism of inhibition.

High-Throughput Image-Based Assay for Identifying In Vitro Hepatocyte Microtubule Disruption.

Disruption of microtubule stability in mammalian cells may lead to genotoxicity and carcinogenesis. The ability to screen for microtubule destabilization or stabilization is therefore a useful and efficient approach to aid in the design of molecules that are safe for human health. In this study, we developed a high-throughput 384-well assay combining immunocytochemistry with high-content imaging to assess microtubule disruption in the metabolically competent human liver cell line: HepaRG. To enhance analysis throughput, we implemented a supervised machine learning approach using a curated training library of 180 compounds. A majority voting ensemble of eight machine learning classifiers was employed for predicting microtubule disruptions. Our prediction model achieved over 99.0% accuracy and a 98.4% F1 score, which reflects the balance between precision and recall for in-sample validation and 93.5% accuracy and a 94.3% F1 score for out-of-sample validation. This automated image-based testing can provide a simple, high-throughput screening method for early stage discovery compounds to reduce the potential risk of genotoxicity for crop protection product development.

Discovery of benzimidazole-2-amide BNZ-111 as new tubulin inhibitor.

Methyl benzimidazole-2-carbamate anthelmintics are a class of oral drugs to treat parasitic worm infections via microtubule disruption for non-systemic indications and currently in use. In order to use for anticancer treatment, the new benzimidazoles needs to improve solubility and pharmacokinetic parameters while maintaining its cellular potency as for systemic drug. Structure-activity-relationship on the benzimidazole is thoroughly examined and a novel benzimidazole-2 propionamide BNZ-111 is identified having good oral exposure and bioavailability in rat. Molecular docking study suggests BNZ-111 have a specific binding mode to the ß subunit of curved tubulin. BNZ-111 is potent to cancer cells and possesses good drug-like properties as oral drug. Especially, BNZ-111 is not a P-gp substrate and it demonstrates its efficacy over Paclitaxel-resistance tumor in vivo.

Construction and validation of co-expression vector for rice alpha tubulin and microtubule associated protein respectively fused with fluorescent proteins.

Microtubule (MT) consists of α-tubulin and ß-tubulin. The dynamic instability regulated by various microtubule associated proteins (MAPs) is essential for MT functions. To analyze the interaction between tubulin/MT and MAP in vivo, we usually need tubulin and MAP co-expressed. Here, we constructed a dual-transgene vector expressing rice (Oryza sativa) α-tubulin and MAP simultaneously. To construct this vector, plant expression vector pCambia1301 was used as the plasmid backbone and Gibson assembly cloning technology was used. We first fused and cloned the GFP fragment, α-tubulin open reading frame (ORF), and NOS terminator into the vector pCambia1301 to construct the p35S::GFP-α-tubulin vector that expressed GFP-α-tubulin fusion protein. Subsequently, we fused and cloned the CaMV 35S promoter, mCherry fragment, and NOS terminator into the p35S::GFP-α-tubulin vector to generate the universal dual-transgene expression vector (p35S::GFP-α-tubulin-p35S::mCherry vector). With the p35S::GFP-α-tubulin-p35S::mCherry vector, MAP ORF can be cloned into the site of 5' or 3' terminus of mCherry to co-express GFP-α-tubulin and MAP-mCherry/mCherry-MAP. To validate the availability and universality of the dual-transgene expression vector, a series of putative rice MAP genes including GL7, OsKCBP, OsCLASP, and OsMOR1 were cloned into the vector respectively, transformed into Agrobacterium tumefaciens strain, and expressed in Nicotiana benthamiana leaves. The results indicated that all of the MAPs were co-expressed with α-tubulin and localized to MTs, validating the availability and universality of the vector and that GL7, OsKCBP, OsCLASP, and OsMOR1 might be MAPs. The application of the co-expression vector constructed by us would facilitate studies on the interaction between tubulin/MT and MAP in tobacco transient expression systems or transgenic rice.

Thiostrepton induces spindle abnormalities and enhances Taxol cytotoxicity in MDA-MB-231 cells.

BACKGROUND: Thiostrepton (TST) is a known inhibitor of the transcription factor Forkhead box M1 (FoxM1) and inducer of heat shock response (HSR) and autophagy. TST thus may be one potential candidate of anticancer drugs for combination chemotherapy. METHODS AND RESULTS: Immunofluorescence staining of mitotic spindles and flow cytometry analysis revealed that TST induces mitotic spindle abnormalities, mitotic arrest, and apoptotic cell death in the MDA-MB-231 triple-negative breast cancer cell line. Interestingly, overexpression or depletion of FoxM1 in MDA-MB-231 cells did not affect TST induction of spindle abnormalities; however, TST-induced spindle defects were enhanced by inhibition of HSP70 or autophagy. Moreover, TST exhibited low affinity for tubulin and only slightly inhibited in vitro tubulin polymerization, but it severely impeded tubulin polymerization and destabilized microtubules in arrested mitotic MDA-MB-231 cells. Additionally, TST significantly enhanced Taxol cytotoxicity. TST also caused cytotoxicity and spindle abnormalities in a Taxol-resistant cell line, MDA-MB-231-T4R. CONCLUSIONS: These results suggest that, in addition to inhibiting FoxM1, TST may induce proteotoxicity and autophagy to disrupt cellular tubulin polymerization, and this mechanism might account for its antimitotic effects, enhancement of Taxol anticancer effects, and ability to overcome Taxol resistance in MDA-MB-231 cells. These data further imply that TST may be useful to improve the therapeutic efficacy of Taxol.

Discovery of novel 2-substituted 2, 3-dihydroquinazolin-4(1H)-one derivatives as tubulin polymerization inhibitors for anticancer therapy: The in vitro and in vivo biological evaluation.

A series of novel 2-substituted 2, 3-dihydroquinazolin-4(1H)-one derivatives were designed, synthesized and estimated for their in vitro antiproliferative activities against HepG2, U251, PANC-1, A549 and A375 cell lines. Among them, compound 32 was the most promising candidate, and displayed strong broad-spectrum anticancer activity. The mechanism studies revealed that compound 32 inhibited tubulin polymerization in vitro, disrupted cell microtubule networks, arrested the cell cycle at G2/M phase, and induced apoptosis by up-regulating the expression of cleaved PARP-1 and caspase-3. Furthermore, molecular docking analysis suggested that compound 32 well occupied the binding site of tubulin. In addition, compound 32 exhibited no significant activity against 30 different kinases respectively, indicating considerable selectivity. Moreover, compound 32 significantly inhibited the tumour growth of the HepG2 xenograft in a nude mouse model by oral gavage without apparent toxicity. These results demonstrated that some 2-substituted 2, 3- dihydroquinazolin-4(1H)-one derivatives bearing phenyl, biphenyl, naphthyl or indolyl side chain at C2-position might be potentially novel antitumor agents as tubulin polymerization inhibitors.

Epigallocatechin gallate induces apoptosis in multiple myeloma cells through endoplasmic reticulum stress induction and cytoskeletal disruption.

Multiple myeloma (MM) is an incurable plasma cell malignancy that has prompted investigations into new potential therapeutic avenues. Epigallocatechin-3-gallate (EGCG), a major component of green tea, confers antioxidant, anti-inflammatory, and anti-tumor properties. Previous studies have shown that EGCG inhibits proliferation and induces apoptosis of multiple myeloma cells, however its underlying molecular mechanisms are largely unknown. In this study, we accordingly sought to examine the therapeutic effects and underlying mechanisms of EGCG on MM. Initially, using CCK8 (Cell Counting Kit-8) assays and Annexin V-FITC/PI staining, we demonstrated that EGCG dose-dependently reduced cell viability and induced apoptosis in the MM cell lines MM.1S and RPMI 8226. Subsequently, mRNA sequencing of EGCG-treated MM.1S cells revealed a significant upregulation of genes associated with endoplasmic reticulum stress (ERS), including P-eIF2α (phosphorylation-eukaryotic translation initiation factor 2 alpha), ATF4 (activating transcription factor 4), CHOP (C/EBP homologous protein, DDIT3), and PUMA (p53 upregulated modulator of apoptosis, BBC3), which were confirmed at the protein level by western blotting. Furthermore, treatment with the eIF2α inhibitor ISRIB reduced the rates of EGCG-induced apoptosis and promoted increases in the protein expression of all four ER stress-related molecules in MM cells. Additionally, mRNA-seq data revealed a downregulation of α-Tubulin 1b (TUBA1B) expression in EGCG-treated MM cells, which was confirmed by western blotting and immunofluorescence analyses. Moreover, we utilized a mouse model to show that EGCG inhibited myeloma tumor growth, which was inhibited by ISRIB. In summary, the findings of this novel study indicated that EGCG promotes apoptosis of MM cells, both via activation of the ER stress pathway and disruption of cytoskeletal integrity. These findings highlight the multi-faceted anti-tumor effects of EGCG and its potential clinical application in MM treatment.

Advancing cellular insights: Super-resolution STORM imaging of cytoskeletal structures in human stem and cancer cells.

Fluorescence microscopy is an important tool for cell biology and cancer research. Present-day approach of implementing advanced optical microscopy methods combined with immunofluorescence labelling of specific proteins in cells is now able to deliver optical super-resolution up to ∼25 nm. Here we perform super-resolved imaging using standard immunostaining protocol combined with easy stochastic optical reconstruction microscopy (easySTORM) to observe structural differences of two cytoskeleton elements, actin and tubulin in three different cell types namely human bone marrow-derived mesenchymal stem cells (MSCs), human glioblastoma (U87MG) and breast cancer (MDAMB-231) cells. The average width of the actin bundle obtained from STORM images of stem cells is observed to be larger than the same for U87MG and MDAMB-231 cells. No significant difference is however noticed in the width of the tubulin within the same cells. We also study the functional effect on the 2D migration potential of MDAMB-231 cells silenced for NICD1 and ß-catenin. Although similar migration speed is observed for cells with the above two conditions compared to their control cells, easySTORM images show that widths of the actin in MDAMB-231 cells in ß-catenin silenced is significantly lower than the same in control cells. Such minute differences however are not observable in widefield images. The outcome of our easySTORM investigation should benefit the researchers carrying out detailed investigations of the cellular structure and potential therapeutic applications.

Approaches for the discovery of cinnamic acid derivatives with anticancer potential.

INTRODUCTION: Cinnamic acid is a privileged scaffold for the design of biologically active compounds with putative anticancer potential, following different synthetic methodologies and procedures. Since there is a need for the production of potent anticancer, cinnamate moiety can significantly contribute in the design of new and more active anticancer agents. AREAS COVERED: In this review, the authors provide a review on the synthetic approaches for the discovery of cinnamic acid derivatives with anticancer potential. Results from molecular simulations, hybridization, and chemical derivatization along with biological experiments in vitro and structural activity relationships are given, described, and discussed by the authors. Information for the mechanism of action is taken from original literature sources. EXPERT OPINION: The authors suggest that (i) numerous areas of biology-pharmacology need to be considered: selectivity, in vivo studies, toxicity and drug-likeness, the mechanism of action in animals and humans, development of more efficient assays for various cancer types; (ii) hybridization techniques outbalance in the discovery and production of compounds with higher activity and greater selectivity; (iii) repositioning offers new anticancer cinnamic agents.

Discovery of novel thiophene[3,2-d]pyrimidine-based tubulin inhibitors with enhanced antitumor efficacy for combined use with anti-pd-l1 immunotherapy in melanoma.

Herein, we designed and synthesized a series of novel 2-methylthieno [3,2-d]pyrimidine analogues as tubulin inhibitors with antiproliferative activities at low nanomolar levels. Among them, compound DPP-21 displayed the most potent anti-proliferative activity against six cancer cell lines with an average IC50 of ∼6.23 nM, better than that of colchicine (IC50 = 9.26 nM). DPP-21 exerted its anti-cancer activity by suppressing the polymerization of tubulin with an IC50 of 2.4 µM. Furthermore, the crystal structure of DPP-21 in complex with tubulin was solved by X-ray crystallography to 2.94 Å resolution, confirming the direct binding of DPP-21 to the colchicine site. Moreover, DPP-21 arrested the cell cycle in the G2/M phase of mitosis, subsequently inducing tumor cell apoptosis. Additionally, DPP-21 was able to effectively inhibit the migration of cancer cells. Besides, DPP-21 exhibited significant in vivo anti-tumor efficacy in a B16-F10 melanoma tumor model with a TGI of 63.3 % (7 mg/kg) by intraperitoneal (i.p.) injection. Notably, the combination of DPP-21 with NP-19 (a PD-L1-targeting small molecule inhibitor reported by our group before) demonstrated enhanced anti-cancer efficacy in vivo. These results suggest that DPP-21 is a promising lead compound deserving further investigation as a potential anti-cancer agent.

From Sea Sponge to Clinical Trials: Starting the Journey of the Novel Compound PM742.

PM742 (1), a new chemical entity, has been isolated from the sponge Discodermia du Bocage collected in the Pacific Ocean. This compound showed strong in vitro cytotoxicity against several human tumor cell lines as well as a tubulin depolymerization mechanism of action, which led us to conduct an extensive Structure-Activity-Relationship study through the synthesis of different analogs. As a result, a derivatively named PM534 (2) is currently in its first human Phase I clinical trial. Herein, we present a comprehensive review of the isolation, structural elucidation, and antitumor activities of the parent compound PM742.

Discovery of novel amide derivatives against VEGFR-2/tubulin with potent antitumor and antiangiogenic activity.

Dual-target agents have more advantages than drug combinations for cancer treatment. Here, we designed and synthesized a series of novel VEGFR-2/tubulin dual-target inhibitors through a molecular hybridization strategy, and the activities of all the synthesized compounds were tested against tubulin and VEGFR-2. Among which, compound 19 exhibited strong potency against tubulin and VEGFR-2, with IC50 values of 0.76 ± 0.11 µM and 15.33 ± 2.12 nM, respectively. Additionally, compound 19 not only had significant antiproliferative effects on a series of human cancer cell lines, especially MGC-803 cells (IC50 = 0.005 ± 0.001 µM) but also overcame drug resistance in Taxol-resistant MGC-803 cells, with an RI of 1.8. Further studies showed that compound 19 could induce tumor cell apoptosis by reducing the mitochondrial membrane potential, increasing the level of ROS, facilitating the induction of G2/M phase arrest, and inhibiting the migration and invasion of tumor cells in a dose-dependent manner. In addition, compound 19 also exhibits potent antiangiogenic effects by blocking the VEGFR-2/PI3K/AKT pathway and inhibiting the tubule formation, invasion, and migration of HUVECs. More importantly, compound 19 demonstrated favorable pharmacokinetic profiles, robust in vivo antitumor efficacy, and satisfactory safety profiles. Overall, compound 19 can be used as a lead compound for the development of tubulin/VEGFR-2 dual-target inhibitors.