Discovery of small molecule cancer drugs: successes, challenges and opportunities

Assessment of cytotoxic and genotoxic potentials of a mononuclear Fe(II) Schiff base complex with photocatalytic activity in Trigonella

BACKGROUND

In recent times, coordination complexes of iron in various oxidation states along with variety of ligand systems have been designed and developed for effective treatment of cancer cells without adversely affecting the normal cell and tissues of various organs.

METHODS

In this study, we have evaluated the mechanism of action of a Fe(II) Schiff base complex in the crop plant Trigonella foenum-graecum L. (Fenugreek) as the screening system by using morphological, cytological, biochemical and molecular approaches. Further functional characterization was performed using MCF-7 cell line and solid tumour model for the assessment of anti-tumour activity of the complex.

RESULTS

Our results indicate efficiency of the Fe(II) Schiff base complex in the induction of double strand breaks in DNA. Complex treatment clearly induced cytotoxic and genotoxic damage in Trigonella seedlings. The Fe-complex treatment caused cell cycle arrest via the activation of ATM-ATR kinase mediated DNA damage response pathway with the compromised expression of CDK1, CDK2 and CyclinB1 protein in Trigonella seedlings. In cultured MCF-7 cells, the complex induces cytotoxicity and DNA fragmentation through intracellular ROS generation. Fe-complex treatment inhibited tumour growth in solid tumour model with no additional side effects.

CONCLUSION

The growth inhibitory and cytotoxic effects of the complex result from activation of DNA damage response along with oxidative stress and cell cycle arrest.

GENERAL SIGNIFICANCE

Overall, our results have provided comprehensive information on the mechanism of action and efficacy of a Fe(II) Schiff base complex in higher eukaryotic genomes and indicated its future implications as potential therapeutic agent.

Effects of Glycyrrhetic Acid on Human Chronic Myelogenous Leukemia Cells

Objectives

Chronic myelogenous leukemia (CML) is a type of blood cancer that is initially treated with imatinib (first Abl kinase inhibitor). However, some patients with CML develop imatinib resistance. Several new generation drugs have been developed, but do not overcome this problem. Glycyrrhetic acid (GA) is a plant-derived pentacyclic triterpenoid that exhibits multiple pharmacological properties for the treatment of cancers. The current study aimed to investigate the effects of GA on the K562 cell line (Bcr-Abl positive leukemia).

Materials and Methods

The MTT cell proliferation assay was employed to evaluate the cytotoxic effect of GA compared with imatinib (positive control) against leukemia and normal blood cells. For detection of cell death, an apoptotic/necrotic/healthy assay was performed against the K562 cell line. To investigate the kinase inhibitory activity of GA, the Abl1 kinase profiling assay and a molecular docking study were performed.

Results

GA showed Abl kinase inhibitory activity with an IC₅₀ value of 29.2 μM and induced apoptosis in the K562 cell line after 6 h of treatment.

Conclusion

The current findings indicate that this class of plant extract could be a potential candidate for treatment of CML.

Turning liabilities into opportunities: Off-target based drug repurposing in cancer

Targeted drugs and precision medicine have transformed the landscape of cancer therapy and significantly improved patient outcomes in many cases. However, as therapies are becoming more and more tailored to smaller patient populations and acquired resistance is limiting the duration of clinical responses, there is an ever increasing demand for new drugs, which is not easily met considering steadily rising drug attrition rates and development costs. Considering these challenges drug repurposing is an attractive complementary approach to traditional drug discovery that can satisfy some of these needs. This is facilitated by the fact that most targeted drugs, despite their implicit connotation, are not singularly specific, but rather display a wide spectrum of target selectivity. Importantly, some of the unintended drug "off-targets" are known anticancer targets in their own right. Others are becoming recognized as such in the process of elucidating off-target mechanisms that in fact are responsible for a drug's anticancer activity, thereby revealing potentially new cancer vulnerabilities. Harnessing such beneficial off-target effects can therefore lead to novel and promising precision medicine approaches. Here, we will discuss experimental and computational methods that are employed to specifically develop single target and network-based off-target repurposing strategies, for instance with drug combinations or polypharmacology drugs. By illustrating concrete examples that have led to clinical translation we will furthermore examine the various scientific and non-scientific factors that cumulatively determine the success of these efforts and thus can inform the future development of new and potentially lifesaving off-target based drug repurposing strategies for cancers that constitute important unmet medical needs.

Patent spotlight: small-molecule lysine acetyltransferase inhibitors (KATi)

Lysine (or histone) acetyltransferases plays a key role in genome maintenance and gene regulation and dysregulation of acetylation is a recognized feature of many diseases, including several cancers. Here, the patent landscape surrounding lysine acetyltransferase inhibitors (KATi or HATi), with a focus on small-molecule compounds, is outlined and assessed. Overall, the 36 KATi-specific patents found were categorized into two distinct groups: specific small-molecule inhibitors (compounds and molecules) and patents applying KATi for targeted disease treatment. These patents recognize the emergent potential of KATi to significantly impact on the management of many diseases (including multiple cancer types, neurological disorders and immunological syndromes), improving the range of treatments (and drug classes) available for personalized medicine.

New directions in antimalarial target validation

Introduction: Malaria is one of the most prevalent human infections worldwide with over 40% of the world's population living in malaria-endemic areas. In the absence of an effective vaccine, emergence of drug-resistant strains requires urgent drug development. Current methods applied to drug target validation, a crucial step in drug discovery, possess limitations in malaria. These constraints require the development of techniques capable of simplifying the validation of Plasmodial targets.Areas covered: The authors review the current state of the art in techniques used to validate drug targets in malaria, including our contribution - the protein interference assay (PIA) - as an additional tool in rapid in vivo target validation.Expert opinion: Each technique in this review has advantages and disadvantages, implying that future validation efforts should not focus on a single approach, but integrate multiple approaches. PIA is a significant addition to the current toolset of antimalarial validation. Validation of aspartate metabolism as a druggable pathway provided proof of concept of how oligomeric interfaces can be exploited to control specific activity in vivo. PIA has the potential to be applied not only to other enzymes/pathways of the malaria parasite but could, in principle, be extrapolated to other infectious diseases.

High-Throughput Screening Identifies Two Novel Small Molecule Enhancers of Recombinant Protein Expression

As a primary strategy for production of biological drugs, recombinant proteins produced by transient transfection of mammalian cells are essential for both basic research and industrial production. Here, we established a high-throughput screening platform for improving the expression levels of recombinant proteins. In total, 10,011 small molecule compounds were screened through our platform. After two rounds of screening, we identified two compounds, Apicidin and M-344, that significantly enhanced recombinant protein expression. Both of the selected compounds were histone deacetylase inhibitors, suggesting that the two small molecules increased the expression levels of recombinant proteins by promoting histone acetylation. Moreover, both molecules showed low cytotoxicity. Therefore, our findings suggest that these small molecules may have wide applications in the future.

Self-assembly of cholesterol end-capped polymer micelles for controlled drug delivery

BACKGROUND

During the past few decades, drug delivery system (DDS) has attracted many interests because it could enhance the therapeutic effects of drugs and reduce their side effects. The advent of nanotechnology has promoted the development of nanosized DDSs, which could promote drug cellular uptake as well as prolong the half-life in blood circulation. Novel polymer micelles formed by self-assembly of amphiphilic polymers in aqueous solution have emerged as meaningful nanosystems for controlled drug release due to the reversible destabilization of hydrophobic domains under different conditions.

RESULTS

The amphiphilic polymers presented here were composed of cholesterol groups end capped and poly (poly (ethylene glycol) methyl ether methacrylate) (poly (OEGMA)) as tailed segments by the synthesis of cholesterol-based initiator, followed by atom transfer radical polymerization (ATRP) with OEGMA monomer. FT-IR and NMR confirmed the successfully synthesis of products including initiator and polymers as well as the Mw of the polymers were from 33,233 to 89,088 g/mol and their corresponding PDI were from 1.25 to 1.55 by GPC. The average diameter of assembled polymer micelles was in hundreds nanometers demonstrated by DLS, AFM and SEM. The behavior of the amphiphilic polymers as micelles was investigated using pyrene probing to explore their critical micelle concentration (CMC) ranging from 2.53 × 10-4 to 4.33 × 10-4 mg/ml, decided by the balance between cholesterol and poly (OEGMA). Besides, the CMC of amphiphilic polymers, the quercetin (QC) feeding ratio and polarity of solvents determined the QC loading ratio maximized reaching 29.2% certified by UV spectrum, together with the corresponding size and stability changes by DLS and Zeta potential, and thermodynamic changes by TGA and DSC. More significantly, cholesterol end-capped polymer micelles were used as nanosized systems for controlled drug release, not only alleviated the cytotoxicity of QC from 8.6 to 49.9% live cells and also achieved the QC release in control under different conditions, such as the presence of cyclodextrin (CD) and change of pH in aqueous solution.

CONCLUSIONS

The results observed in this study offered a strong foundation for the design of favorable polymer micelles as nanosized systems for controlled drug release, and the molecular weight adjustable amphiphilic polymer micelles held potential for use as controlled drug release system in practical application.

Discovery, biological evaluation, structure-activity relationships and mechanism of action of pyrazolo[3,4-b]pyridin-6-one derivatives as a new class of anticancer agents

We have recently reported computational models for prediction of cell-based anticancer activity using machine learning methods. Herein, we have developed an integrated strategy to discover new anticancer agents using a cascade of the established screening models. Application of this strategy identified 17 compounds with antitumor activity. Among these compounds, h2 (containing a pyrazolo[3,4-b]pyridin-6-one scaffold) exhibited anticancer activity against six tumor cell lines, including MDA-MB-231, HeLa, MCF-7, HepG2, CNE2 and HCT116, with IC50 values of 13.37, 13.04, 15.45, 7.05, 9.30 and 8.93 μM. Subsequently, a total of 61 h2 analogues were obtained by similarity searching and tested for their anticancer activities. I2 was identified as a novel anticancer agent having activity against MDA-MB-231, HeLa, MCF-7, HepG2, CNE2 and HCT116 tumor cell lines with IC50 values of 3.30, 5.04, 5.08, 3.71, 2.99 and 5.72 μM. I2 also showed potent cytotoxicity against adriamycin-resistant human breast and hepatocarcinoma cells. Further investigation revealed that I2 inhibited the microtubule polymerization by binding to the colchicine site, resulting in inhibition of cell migration, cell cycle arrest in the G2/M phase and apoptosis of cancer cells. Finally, molecular docking and molecular dynamics provided insights into the binding interactions of I2 with tubulin. This study identified I2 as a novel starting point for further development of anticancer agents that target tubulin.

Identifying Ortholog Selective Fragment Molecules for Bacterial Glutaredoxins by NMR and Affinity Enhancement by Modification with an Acrylamide Warhead

Illustrated here is the development of a new class of antibiotic lead molecules targeted at Pseudomonas aeruginosa glutaredoxin (PaGRX). This lead was produced to (a) circumvent efflux-mediated resistance mechanisms via covalent inhibition while (b) taking advantage of species selectivity to target a fundamental metabolic pathway. This work involved four components: a novel workflow for generating protein specific fragment hits via independent nuclear magnetic resonance (NMR) measurements, NMR-based modeling of the target protein structure, NMR guided docking of hits, and synthetic modification of the fragment hit with a vinyl cysteine trap moiety, i.e., acrylamide warhead, to generate the chimeric lead. Reactivity of the top warhead-fragment lead suggests that the ortholog selectivity observed for a fragment hit can translate into a substantial kinetic advantage in the mature warhead lead, which bodes well for future work to identify potent, species specific drug molecules targeted against proteins heretofore deemed undruggable.

Antitumor effect of TW-37, a BH3 mimetic in human oral cancer

TW-37 is a small molecule B cell lymphoma-2 (Bcl-2) homology 3 mimetic with potential anticancer activities. However, the in vivo anti-cancer effect of TW-37 in human oral cancer has not been properly studied yet. Here, we attempted to confirm antitumor activity of TW37 in human oral cancer. TW-37 significantly inhibited cell proliferation and increased the number of dead cells in MC-3 and HSC-3 human oral cancer cell lines. TW-37 enhanced apoptosis of both cell lines evidenced by annexin V/propidium iodide double staining, sub-G₁ population analysis and the detection of cleaved poly (ADP-ribose) polymerase and caspase-3. In addition, TW-37 markedly downregulated the expression of Bcl-2 protein, while not affecting Bcl-xL or myeloid cell leukemia-1. In vivo, TW-37 inhibited tumor growth in a nude mice xenograft model without any significant liver and kidney toxicities. Collectively, these data reveal that TW-37 may be a promising small molecule to inhibit human oral cancer.

Polymer conjugated graphene-oxide nanoparticles impair nuclear DNA and Topoisomerase I in cancer

Cancer chemotherapy had been dominated by the use of small molecule DNA damaging drugs. Eventually, the emergence of DNA damage repair machinery in cancer cells has led to combination therapy with the DNA topology controlling enzyme, topoisomerase I inhibitor along with DNA impairing agents. However, integrating multiple drugs having diverse water solubility and hence bio-distribution effectively for cancer treatment remains a significant challenge, which can be addressed by using suitable nano-scale materials. Herein, we have chemically conjugated graphene oxide (GO) with biocompatible and hydrophilic polymers [polyethylene glycol (PEG) and ethylene-diamine modified poly-isobutylene-maleic anhydride (PMA-ED)], which can encompass highly hydrophobic topoisomerase I inhibitor, SN38. Interestingly, these sheet structured GO-polymer-SN38 composites self-assembled into spherical nanoparticles in water after complexing with a hydrophilic DNA damaging drug, cisplatin. These nanoparticles showed much improved colloidal stability in water compared to their drug-loaded non-polymeric counterpart. These SN38 and cisplatin laden GO-polymer nanoparticles were taken up by HeLa cancer cells through clathrin-dependent endocytosis to home into lysosomes within 6 h, as confirmed by confocal microscopy. A combination of gel electrophoresis, flow cytometry, and fluorescence microscopy showed that these nanoparticles damaged nuclear DNA and induced topoisomerase I inhibition leading to apoptosis and finally improved HeLa cell death. These self-assembled GO-polymer nanoparticles can be used for strategic impairment of multiple cellular targets involving hydrophobic and hydrophilic drugs for effective combination therapy.

A high-affinity human PD-1/PD-L2 complex informs avenues for small-molecule immune checkpoint drug discovery

Immune checkpoint blockade of programmed death-1 (PD-1) by monoclonal antibody drugs has transformed the treatment of cancer. Small-molecule PD-1 drugs have the potential to offer increased efficacy, safety, and global access. Despite substantial efforts, such small-molecule drugs have been out of reach. We identify a prominent pocket on the ligand-binding surface of human PD-1 that appears to be an attractive small-molecule drug target. The pocket forms when PD-1 is bound to one of its ligands, PD-L2. Our high-resolution crystal structure of the human PD-1/PD-L2 complex facilitates virtual drug-screening efforts and opens additional avenues for the design and discovery of small-molecule PD-1 inhibitors. Our work provides a strategy that may enable discovery of small-molecule inhibitors of other “undruggable” protein–protein interactions.

Immune checkpoint blockade of programmed death-1 (PD-1) by monoclonal antibody drugs has delivered breakthroughs in the treatment of cancer. Nonetheless, small-molecule PD-1 inhibitors could lead to increases in treatment efficacy, safety, and global access. While the ligand-binding surface of apo-PD-1 is relatively flat, it harbors a striking pocket in the murine PD-1/PD-L2 structure. An analogous pocket in human PD-1 may serve as a small-molecule drug target, but the structure of the human complex is unknown. Because the CC′ and FG loops in murine PD-1 adopt new conformations upon binding PD-L2, we hypothesized that mutations in these two loops could be coupled to pocket formation and alter PD-1’s affinity for PD-L2. Here, we conducted deep mutational scanning in these loops and used yeast surface display to select for enhanced PD-L2 binding. A PD-1 variant with three substitutions binds PD-L2 with an affinity two orders of magnitude higher than that of the wild-type protein, permitting crystallization of the complex. We determined the X-ray crystal structures of the human triple-mutant PD-1/PD-L2 complex and the apo triple-mutant PD-1 variant at 2.0 Å and 1.2 Å resolution, respectively. Binding of PD-L2 is accompanied by formation of a prominent pocket in human PD-1, as well as substantial conformational changes in the CC′ and FG loops. The structure of the apo triple-mutant PD-1 shows that the CC′ loop adopts the ligand-bound conformation, providing support for allostery between the loop and pocket. This human PD-1/PD-L2 structure provide critical insights for the design and discovery of small-molecule PD-1 inhibitors.

AGS-30, an andrographolide derivative, suppresses tumor angiogenesis and growth in vitro and in vivo

Poor bioavailability and limited efficacy are challenges associated with using andrographolide as a therapeutic agent. We recently synthesized AGS-30, a new andrographolide derivative, in our laboratory. In this study we investigated the potential anti-tumor effect of AGS-30 and the underlying mechanisms, particularly those related to angiogenesis. Results from our in vitro experiments showed that AGS-30 exerted anti-angiogenic effects by inhibiting endothelial cell proliferation, migration, invasion, and tube formation. Phosphorylation and activation of angiogenesis-related signaling molecules (e.g., vascular endothelial growth factor [VEGF] receptor 2, mitogen-activated protein kinase kinase 1/2, extracellular signal-regulated kinase 1/2, mechanistic target of rapamycin [mTOR], protein kinase B [Akt], and p38) were markedly reduced by AGS-30. Meanwhile, AGS-30 potently inhibited cell proliferation and phosphorylation of cell survival-related proteins (e.g., Akt, mTOR, and ERK1/2) and decreased the expression of VEGF in HT-29 colon cancer cells. AGS-30 blocked microvessel sprouting in a rat aortic ring model and blood vessel formation in zebrafish embryos and a mouse Matrigel plug model. Additionally, AGS-30 suppressed tumor growth and angiogenesis in HT-29 colon cancer cell xenografts in nude mice. These effects were not observed when same concentration of andrographolide, the parent compound of AGS-30, was used. Thus, AGS-30 exerted a strong antitumor effect by inhibiting tumor cell growth and angiogenesis and is a candidate compound for the treatment of cancer.

Harnessing the therapeutic potential of anticancer drugs through amorphous solid dispersions

The treatment of cancer is still a major challenge. But tremendous progress in anticancer drug discovery and development has occurred in the last few decades. However, this progress has resulted in few effective oncology products due to challenges associated with anticancer drug delivery. Oral administration is the most preferred route for anticancer drug delivery, but the majority of anticancer drugs currently in product pipelines and the majority of those that have been commercially approved have inherently poor water solubility, and this cannot be mitigated without compromising their potency and stability. The poor water solubility of anticancer drugs, in conjunction with other factors, leads to suboptimal pharmacokinetic performance. Thus, these drugs have limited efficacy and safety when administered orally. The amorphous solid dispersion (ASD) is a promising formulation technology that primarily enhances the aqueous solubility of poorly water-soluble drugs. In this review, we discuss the challenges associated with the oral administration of anticancer drugs and the use of ASD technology in alleviating these challenges. We emphasize the ability of ASDs to improve not only the pharmacokinetics of poorly water-soluble anticancer drugs, but also their efficacy and safety. The goal of this paper is to rationalize the application of ASD technology in the formulation of anticancer drugs, thereby creating superior oncology products that lead to improved therapeutic outcomes.

Targeted cancer therapies: Oral health care implications

BACKGROUND

Targeted treatments have been incorporated into oncology protocols, often with more traditional therapies, and are not totally free of adverse reactions, some of which affect the orofacial region.

METHODS

The authors searched PubMed, the Cochrane Library, and the US Food and Drug Administration Approved Drug Products database to identify reported adverse effects of targeted agents in the orofacial region as well as other implications in oral health care. Their principal focus was the relatively newer category of molecularly targeted drugs which are called small molecules (SMs).

RESULTS

The authors identified several categories of SMs and biological agents (for example, monoclonal antibodies) with adverse effects in the orofacial region. The oral and perioral regions are also fields for which there are therapeutic applications for targeted therapies, particularly to treat malignant neoplasms such as head and neck cancers.

CONCLUSIONS

SMs are the most rapidly growing group of targeted cancer treatments. Patients receiving SMs and other targeted antineoplastic agents may require oral medicine advice and special-care dentistry.

PRACTICAL IMPLICATIONS

In this narrative review, the authors focus mainly on the orofacial adverse effects of targeted cancer therapies and outline many of the agents that are in use so the dentally focused reader can familiarize themselves with these adverse effects and agents.

Cytotoxic effects of Pseudocerastes persicus venom and its HPLC fractions on lung cancer cells

BACKGROUND

Several studies have pointed out that certain snake venoms contain compounds presenting cytotoxic activities that selectively interfere with cancer cell metabolism. In this study, Pseudocerastes persicus venom and its fractions were investigated for their anticancer potential on lung cancer cells.

METHODS

Lung cancer cells (A549) and normal fibroblast cells (Hu02) were treated with the P. persicus venom and its HPLC fractions and the cell cytotoxic effects were analyzed using MTT and lactate dehydrogenase release assays. Apoptosis was determined in venom-treated cell cultures using caspase-3 and caspase-9 assay kits.

RESULTS

The treatment of cells with HPLC fraction 21 (25-35 kDa) of P. persicus venom resulted in high LDH release in normal fibroblast cells and high caspase-3 and caspase-9 activities in lung cancer cells. These results indicate that fraction 21 induces apoptosis in cancer cells, whereas necrosis is predominantly caused by cell death in the normal cells. Fraction 21 at the final concentration of 10 μg/mL killed approximately 60% of lung cancer cells, while in normal fibroblast cells very low cell cytotoxic effect was observed.

CONCLUSION

HPLC fraction 21 at low concentrations displayed promising anticancer properties with apoptosis induction in the lung cancer cells. This fraction may, therefore, be considered a promising candidate for further studies.

Effect of early-stage autophagy inhibition in BRAFV600E autophagy-dependent brain tumor cells

Autophagy is a multistage process. Progress within the field has led to the development of agents targeting both early (initiation) and late (fusion) stages of this process. The specific stage of autophagy targeted may influence cancer treatment outcomes. We have previously shown that central nervous system (CNS) tumors with the BRAF^V600E mutation are autophagy dependent, and late-stage autophagy inhibition improves the response to targeted BRAF inhibitors (BRAFi) in sensitive and resistant cells. Drugs directed toward initiation of autophagy have been shown to reduce tumor cell death in some cancers, but have not been assessed in CNS tumors. We investigated early-stage inhibition for autophagy-dependent CNS tumors. BRAFi-sensitive and resistant AM38 and MAF794 cell lines were evaluated for the response to pharmacologic and genetic inhibition of ULK1 and VPS34, two crucial subunits of the autophagy initiation complexes. Changes in autophagy were monitored by western blot and flow cytometry. Survival was evaluated in short- and long-term growth assays. Tumor cells exhibited a reduced autophagic flux with pharmacologic and genetic inhibition of ULK1 or VPS34. Pharmacologic inhibition reduced cell survival in a dose-dependent manner for both targets. Genetic inhibition reduced cell survival and confirmed that it was an autophagy-specific effect. Pharmacologic and genetic inhibition were also synergistic with BRAFi, irrespective of RAFi sensitivity. Inhibition of ULK1 and VPS34 are potentially viable clinical targets in autophagy-dependent CNS tumors. Further evaluation is needed to determine if early-stage autophagy inhibition is equal to late-stage inhibition to determine the optimal clinical target for patients.

Preclinical Imaging in Targeted Cancer Therapies

Preclinical imaging with radiolabeled probes can provide noninvasive tools to test the efficacy of targeted agents in tumors harboring specific genetic alterations and to identify imaging parameters that can be used as pharmacodynamics markers in cancer patients. The present review will primarily focus on preclinical imaging studies that can accelerate the clinical approval of targeted agents and promote the development of imaging biomarkers for clinical applications. Since only subgroups of patients may benefit from treatment with targeted anticancer agents, the identification of a patient population expressing the target is of primary importance for the success of clinical trials. Preclinical imaging studies tested the ability of new radiolabeled compounds to recognize mutant, amplified, or overexpressed targets and some of these tracers were transferred to the clinical setting. More common tracers such as ¹⁸F-Fluorothymidine and ¹⁸F-Fluorodeoxyglucose were employed in animal models to test the inhibition of the target and downstream pathways through the evaluation of early changes of proliferation and glucose metabolism allowing the identification of sensitive and resistant tumors. Furthermore, since the majority of patients treated with targeted anticancer agents will invariably develop resistance, preclinical imaging studies were performed to test the efficacy of reversal agents to overcome resistance. These studies provided consistent evidence that imaging with radiolabeled probes can monitor the reversal of drug resistance by newly designed alternative compounds. Finally, despite many difficulties and challenges, preclinical imaging studies targeting the expression of immune checkpoints proved the principle that it is feasible to select patients for immunotherapy based on imaging findings. In conclusion, preclinical imaging can be considered as an integral part of the complex translational process that moves a newly developed targeted agent from laboratory to clinical application intervening in all clinically relevant steps including patient selection, early monitoring of drug effects and reversal of drug resistance.

p53 pulse modulation differentially regulates target gene promoters to regulate cell fate decisions

The p53 tumor suppressor regulates distinct responses to cellular stresses. Although different stresses generate different p53 dynamics, the mechanisms by which cells decode p53 dynamics to differentially regulate target genes are not well understood. Here, we determined in individual cells how canonical p53 target gene promoters vary in responsiveness to features of p53 dynamics. Employing a chemical perturbation approach, we independently modulated p53 pulse amplitude, duration, or frequency, and we then monitored p53 levels and target promoter activation in individual cells. We identified distinct signal processing features-thresholding in response to amplitude modulation, a refractory period in response to duration modulation, and dynamic filtering in response to frequency modulation. We then showed that the signal processing features not only affect p53 target promoter activation, they also affect p53 regulation and downstream cellular functions. Our study shows how different promoters can differentially decode features of p53 dynamics to generate distinct responses, providing insight into how perturbing p53 dynamics can be used to generate distinct cell fates.

Structure-based virtual screening, molecular dynamics simulation and MM-PBSA toward identifying the inhibitors for two-component regulatory system protein NarL of Mycobacterium Tuberculosis

The nitrate/nitrite response regulatory protein NarL belongs to the two-component regulatory system of Mycobacterium tuberculosis (MTB), plays a crucial role in anaerobic survival of mycobacteria in host. The absence of this protein in humans, makes it an attractive drug target for MTB treatment. However, the specific drug molecules targeting NarL are yet to be identified. In this study, we identified the promising drug candidates using structure based virtual screening of compounds from chemical libraries (ChEMBL and ZINC), followed by the extensive physicochemical properties analyses and molecular dynamics (MD) simulation. As the initial results, we obtained 4,754 bioactive compounds from ChEMBL having anti-tuberculosis activity which is finally narrowed down to the best 10 hits. A similar approach was applied to search for structurally similar compounds from ZINC data, corresponding to the top hits obtained from ChEMBL. Our collective results show that two compounds, ChEMBL509609 (Gscore - 5.054 kcal/mol, Xscore - 6.47 kcal/mol) and ZINC01843143 (Gscore - 5.114 kcal/mol, Xscore - 6.46 kcal/mol) having the best docking score and ADMET profile. The structural stability and dynamics of lead molecules at active site of NarL were examined using MD simulation and the binding free energies were estimated with MM-PBSA. Essential dynamics and MM-PBSA demonstrated that NarL-ChEMBL509609 complex remains the most stable during simulation of 100 ns with the higher binding free energy which may be a suitable candidate for further experimental analysis. AbbreviationsADMEAbsorption, Distribution, Metabolism, And ExcretionBCGBacillus Calmette-GuerinCNSCentral nervous systemDOTSDirectly observed treatment, short courseEDEssential dynamicsHIVHuman immunodeficiency virusHKHistidine kinaseHOAHuman oral absorptionHTVSHigh throughput virtual screeningIRRIIrritationMDMolecular dynamicsMDRMultidrug resistantMTBMycobacterium tuberculosisMUTMutagenicityMWMolecular weightPHOAPercentage of human oral absorptionREPReproductive developmentRgRadius of gyrationRMSDRoot mean square deviationRMSFRoot mean square fluctuationRO5Lipinski's rule of fiveRRResponse regulatorSPStandard precisionSPGStandard precision glideTBTuberculosisTCSTwo-component regulatory systemTDRTotally drug-resistantTUMOTumorigenicityWHOWorld health organizationXDRExtensively drug-resistantXPExtra precisionCommunicated by Ramaswamy H. Sarma.

Small molecule immunomodulation: the tumor microenvironment and overcoming immune escape

Immunotherapy has led to a paradigm shift in the treatment of many advanced malignancies. Despite the success in treatment of tumors like non-small cell lung cancer (NSCLC) and melanoma, checkpoint inhibition-based immunotherapy has limitations. Many tumors, such as pancreatic cancer, are less responsive to checkpoint inhibitors, where patients tend to have a limited duration of benefit and where clinical responses are more robust in patients who are positive for predictive biomarkers. One of the critical factors that influence the efficacy of immunotherapy is the tumor microenvironment (TME), which contains a heterogeneous composition of immunosuppressive cells. Myeloid-derived suppressor cells (MDSCs) and tumor-associated macrophages (TAMs) alter the immune landscape of the TME and serve as facilitators of tumor proliferation, metastatic growth and immunotherapy resistance. Small molecule inhibitors that target these components of the TME have been developed. This special issue review focuses on two promising classes of immunomodulatory small molecule inhibitors: colony stimulating factor-1 receptor (CSF-1R) and focal adhesion kinase (FAK). Small molecule inhibitors of CSF-1R reprogram the TME and TAMs, and lead to enhanced T-cell-mediated tumor eradication. FAK small molecule inhibitors decrease the infiltration MDSCs, TAMs and regulatory T-cells. Additionally, FAK inhibitors are implicated as modulators of stromal density and cancer stem cells, leading to a TME more conducive to an anti-tumor immune response. Immunomodulatory small molecule inhibitors present a unique opportunity to attenuate immune escape of tumors and potentiate the effectiveness of immunotherapy and traditional cytotoxic therapy.

Etiologic Role of Kinases in the Progression of Human Cancers and Its Targeting Strategies

Cancer is one of the dominant causes of death worldwide while lifelong prognosis is still inauspicious. The maturation of the cancer is seen as a process of transformation of a healthy cell into a tumor-sensitive cell, which is held entirely at the cellular, molecular, and genetic levels of the organism. Tyrosine kinases can play a major, etiologic role in the inception of malignancy and devote to the uncontrolled proliferation of cancerous cells and the progression of a tumor as well as the development of metastatic disease. Angiogenesis and oncogene activation are the major event in cell proliferation. The growth of a tumor and metastasis are fully depending on angiogenesis and lymphangiogenesis triggered by chemical signals from tumor cells in a phase of rapid growth. Tyrosine kinase inhibitors are compounds that inhibit tyrosine kinases and effective in targeting angiogenesis and blocking the signaling pathways of oncogenes. Small molecule tyrosine kinase inhibitors like afatinib, erlotinib, crizotinib, gefitinib, and cetuximab are shown to a selective cut off tactic toward the constitutive activation of an oncogene in tumor cells, and thus contemplated as promising therapeutic approaches for the diagnosis of cancer and malignancies.

Cysteine-based redox-responsive nanoparticles for small-molecule agent delivery

As a significant part of molecular-targeted therapies, small-molecule agents (SMAs) have been increasingly used for cancer treatment. Nevertheless, most SMAs are currently administered orally due to their poor solubility, resulting in a low bioavailability and unavoidable side effects. Herein, we proposed a promising SMA delivery strategy using a biocompatible and redox-responsive nanoparticle (NP) delivery system to improve their bioavailability, alleviate side effects and enhance therapeutic performance. To demonstrate the feasibility of this strategy, a type of cysteine-based hydrophobic polymer was employed to construct a redox-sensitive nanoplatform for the delivery of various hydrophobic oral SMAs. These SMA-loaded nanoparticles (SMA-NPs) all have a small particle size and good drug-loading capacity. Particularly, lapatinib-loaded nanoparticles (LAP-NPs) with a minimal particle size (79.71 nm) and an optimal drug-loading capacity (12.5%) were utilized as a model to systemically explore the in vitro and in vivo anticancer potential of SMA-NPs. As expected, the LAP-NPs exhibited rapid redox-responsive drug release, enhanced in vitro cytotoxicity and cell apoptosis, and demonstrated notable anti-metastasis ability and desirable intracellular localization. Additionally, the in vivo results demonstrated the preferential accumulation of LAP-NPs in tumor tissues and the significant suppression of tumor growth. Therefore, the generated SMA-NP delivery system shows great SMA delivery potential for advanced molecular-targeted therapies.

Novel Small Molecule Inhibitors of Programmed Cell Death (PD)-1, and its Ligand, PD-L1 in Cancer Immunotherapy: A Review Update of Patent Literature

Background:

In the last few decades, cancer immunotherapy has been extensively researched, and novel checkpoint signaling mechanisms involving Programmed Death (PD)-1 and PDLigand 1 (PD-L1) receptors have been targeted. The PD-1/PD-L1 binding and interaction play a critical role in the development of malignancies.

Objective:

The present review focuses on recent patents on the pharmacological and biological cancerregulating properties of PD-1/PD-L1 inhibitors involved in immunotherapeutic cancer drug development.

Methods:

Thorough patent literature search published during the last seven years, including the World Intellectual Property Organization (WIPO®), United States Patent Trademark Office (USPTO®), Espacenet®, and Google Patents, to identify PD-1/PD-L1-targeting small molecule immunomodulators.

Results:

Several small molecule PD-1/PD-L1 inhibitors were patented for regulation of tumor progression by academic and industry-associated investigators. Most of the claimed patents have been validated and confined to in vitro and in vivo mouse models limiting their entry into clinical settings. Majority of the patents are claimed by the researchers at Aurigene Ltd. (India) on novel peptidomimetic compounds. It is worth to be noted that macrocyclic compounds such as the peptides QP20, HD20, WQ20, SQ20, and CQ-22 from Bristol-Myers Squibb (BMS) Company, biaryl, and heterocyclic derivatives including 1,3-dihydroxy-phenyl compounds were efficient in regulating the PD-1/PD-L1 protein-protein binding and interaction compared to those of the approved monoclonal antibodies.

Conclusion:

PD-1/PD-L1 inhibitors show significant anti-cancer responses as stand-alone agents and in combination with other cancer therapies. More efficient experimental studies and clinical trials are necessary to evaluate the host-tumor cells’ interactions. Understanding the cancer microenvironment, and identifying specific biomarkers and X-ray crystalline structures of PD-1/PD-L1 complexes, including molecular and genomic signature studies are essential to determine the feasibility of PD-1/PD-L1 inhibitors for development into drug-like cancer immunotherapeutics.

Cationic Pd(IV)-Induced Highly Diastereoselective Arylative Cascade Cyclization of Allene-Tethered Cyclohexadienones Leading to Oxygenated Bicyclic Motifs

A cationic Pd(IV)-catalyzed arylative hydroxylation-Micheal addition of allenyl-tethered cyclohexadienones was developed. This relay reaction could afford highly diastereoselective various functionalized arylative 1,4-dioxane cis-bicyclic structural units with good to high yields. The striking features revealed from these studies is the necessity of Selectfluor and the oxidative hydroxylation originating from water initiated by F-Pd(IV) catalysis. A plausible mechanism was also proposed for this variant observation.

Combined Scaffold Evaluation and Systems-Level Transcriptome-Based Analysis for Accelerated Lead Optimization Reveals Ribosomal Targeting Spirooxindole Cyclopropanes

With evolutionary drug resistance impacting efforts to treat disease, the need for small molecules that exhibit novel molecular mechanisms of action is paramount. In this study, we combined scaffold-directed synthesis with a hybrid experimental and transcriptome analysis to identify bis-spirooxindole cyclopropanes that inhibit cancer cell proliferation through disruption of ribosomal function. These findings demonstrate the value of an integrated, biologically inspired synthesis and assay strategy for the accelerated identification of first-in-class cancer therapeutic candidates.

Monocarboxylate transporter 1 and monocarboxylate transporter 4 in cancer-endothelial co-culturing microenvironments promote proliferation, migration, and invasion of renal cancer cells

Background

The Warburg effect demonstrates the importance of glycolysis in the development of primary and metastatic cancers. We aimed to explore the role of monocarboxylate transporter 1 (MCT1) and MCT4, two essential transporters of lactate, in renal cancer progression during cancer-endothelial cell co-culturing.

Methods

Renal cancer cells (786-O) and human vascular endothelial cells (HUVECs) were single-cultured or co-cultured in transwell membranes in the presence or absence of a MCT-1/MCT-4 specific blocker, 7ACC1. Cell proliferation was evaluated with the CCK-8 kit, while cell migration, after a scratch and invasion in transwell chambers, was evaluated under a microscope. Real-time qPCR and western blot were employed to determine the mRNA and protein levels of MCT1 and MCT4, respectively. The concentration of lactic acid in the culture medium was quantified with an l-Lactic Acid Assay Kit.

Results

786-O cells and HUVECs in the co-culturing mode exhibited significantly enhanced proliferation and migration ability, compared with the cells in the single-culturing mode. The expression of MCT1 and MCT4 was increased in both 786-O cells and HUVECs in the co-culturing mode. Co-culturing promoted the invasive ability of 786-O cells, and markedly increased extracellular lactate. Treatments with 7ACC1 attenuated cell proliferation, migration, and invasion, and down-regulated the levels of MCT1/MCT4 expression and extracellular lactate.

Conclusions

The Warburg effect accompanied with high MCT1/MCT4 expression in the cancer-endothelial microenvironments contributed significantly to renal cancer progression, which sheds new light on targeting MCT1/MCT4 and glycolytic metabolism in order to effectively treat patients with renal cancers.

Computational Studies in Drug Design Against Cancer

Background:

The application of in silico tools in the development of anti cancer drugs.

Objective:

The summing of different computer aided drug design approaches that have been applied in the development of anti cancer drugs.

Methods:

Structure based, ligand based, hybrid protein-ligand pharmacophore methods, Homology modeling, molecular docking aids in different steps of drug discovery pipeline with considerable saving in time and expenditure. In silico tools also find applications in the domain of cancer drug development.

Results:

Structure-based pharmacophore modeling aided in the identification of PUMA inhibitors, structure based approach with high throughput screening for the development of Bcl-2 inhibitors, to derive the most relevant protein-protein interactions, anti mitotic agents; I-Kappa-B Kinase β (IKK- β) inhibitor, screening of new class of aromatase inhibitors that can be important targets in cancer therapy.

Conclusion:

Application of computational methods in the design of anti cancer drugs was found to be effective.

In-silico Prediction of Synergistic Anti-Cancer Drug Combinations Using Multi-omics Data

Chemotherapy is a routine treatment approach for early-stage cancers, but the effectiveness of such treatments is often limited by drug resistance, toxicity, and tumor heterogeneity. Combination chemotherapy, in which two or more drugs are applied simultaneously, offers one promising approach to address these concerns, since two single-target drugs may synergize with one another through interconnected biological processes. However, the identification of effective dual therapies has been particularly challenging; because the search space is large, combination success rates are low. Here, we present our method for DREAM AstraZeneca-Sanger Drug Combination Prediction Challenge to predict synergistic drug combinations. Our approach involves using biologically relevant drug and cell line features with machine learning. Our machine learning model obtained the primary metric = 0.36 and the tie-breaker metric = 0.37 in the extension round of the challenge which was ranked in top 15 out of 76 submissions. Our approach also achieves a mean primary metric of 0.39 with ten repetitions of 10-fold cross-validation. Further, we analyzed our model's predictions to better understand the molecular processes underlying synergy and discovered that key regulators of tumorigenesis such as TNFA and BRAF are often targets in synergistic interactions, while MYC is often duplicated. Through further analysis of our predictions, we were also ble to gain insight into mechanisms and potential biomarkers of synergistic drug pairs.

ZnO Nanoparticles Catalyst in the Synthesis of Bioactive Fused Pyrimidines as Anti-breast Cancer Agents Targeting VEGFR-2

BACKGROUND

Pyrimidines emerged as a remarkable class of heterocyclic compounds that have reinforced the pharmaceutical chemistry with various bioactive antitumor agents. Moreover, pyrimidine scaffold displayed VEGFR-2 inhibitory activity. Also, nano-sized catalysts are used in organic reactions in order to speed up the catalytic process.

OBJECTIVE

We were interested herein to synthesize a new series of fused pyrimidines using ZnO(NPs) to investigate their antitumor efficiency against breast MCF7 cancer and their VEGFR- 2 inhibition properties.

METHOD

A simple and efficient method for the synthesis of fused pyrimidines was developed using zinc oxide nanoparticles ZnO(NPs) in refluxing ethanol.

RESULTS

The proposed structures of all new fused pyrimidines are in agreement with their spectral data. Antitumor evaluation of newly fused pyrimidine derivatives against breast MCF-7 cancer was performed. It was apparent that the 2-phenylpyrazolo[1,5-a]pyrimidine derivatives 9a (IC50 = 9.12±1.16 µg/ml), 9c (IC50 = 9.10±1.07 µg/ml) and 9d (IC50 = 9.60±1.22 µg/ml) exhibited equipotent antitumor activity as Tamoxifen (IC50 = 9.11±0.90 µg/ml). Also, the inhibitory activity of the novel fused pyrimidine derivatives on VEGFR-2 as well as Tamoxifen was determined using breast cancer cell line MCF-7. The data was obvious that 2-phenylpyrazolo[1,5-a]pyrimidine derivatives 9a, 9c and 9d exhibited noticeable VEGFR-2 inhibitory effect with % inhibition ranging from 80-84 % versus Tamoxifen 93.5%.

CONCLUSION

We succeeded in this context to synthesize new fused pyrimidines using ZnO(NPs) as anti-breast cancer agents targeting VEGFR-2.

Synthesis and antitumor activity of 2-isocamphanyl thiosemicarbazone derivatives via ROS-enhanced mitochondrial damage

A series of novel 2-isocamphanyl thiosemicarbazone derivatives were synthesized and characterized by ¹ H NMR, ¹³ C NMR, and HRMS. In in vitro anticancer activity, most derivatives showed considerable cytotoxic activity against four cancer cell lines (RPMI-8226, A549, MDA-MB-231, and HepG2 cancer cells) and showed low toxicity against human gastric mucosal cells (GES-1). Among them, compound 4h exhibited excellent antitumor activity against the tested cancer cells with IC₅₀ values of 0.4, 1.1, 1.6, and 1.7 μM for MDA-MB-231, RPMI-8226, A549, and HepG2, respectively. Further, mechanism studies indicated that compound 4h induced apoptosis in MDA-MB-231 cells through enhancing reactive oxygen species levels, inducing mitochondrial membrane potential decrease, and influencing the expression of Bax, Bcl-2, caspase-3, and caspase-9.

Discovery of a new autophagy inducer for A549 lung cancer cells

Biological activities of a series of fluorescent compounds against human lung cancer cell line A549 were investigated. The results showed that (E)-1,3,3-trimethyl-2-(4-(piperidin-1-yl)styryl)-3H-indol-1-ium iodide (8) and (E)-2-(5,5-dimethyl-3-(4-(piperazin-1-yl)styryl)cyclohex-2-en-1-ylidene) malononitrile (11) could inhibit the growth of A549 cancer cells in a dose and time-dependent manner. Furthermore, compound 8 could trigger autophagy and apoptosis, but not obviously induce necrosis under the stimulatory condition. Therefore, 8 can be used as autophagy activator to investigate the regulatory mechanism of autophagy and may offer a new candidate for the treatment of lung cancer.

Pluripotent stem cells: induction and self-renewal

Pluripotent stem cells (PSCs) lie at the heart of modern regenerative medicine due to their properties of unlimited self-renewal in vitro and their ability to differentiate into cell types representative of the three embryonic germ layers-mesoderm, ectoderm and endoderm. The derivation of induced PSCs bypasses ethical concerns associated with the use of human embryonic stem cells and also enables personalized cell-based therapies. To exploit their regenerative potential, it is essential to have a firm understanding of the molecular processes associated with their induction from somatic cells. This understanding serves two purposes: first, to enable efficient, reliable and cost-effective production of excellent quality induced PSCs and, second, to enable the derivation of safe, good manufacturing practice-grade transplantable donor cells. Here, we review the reprogramming process of somatic cells into induced PSCs and associated mechanisms with emphasis on self-renewal, epigenetic control, mitochondrial bioenergetics, sub-states of pluripotency, naive ground state, naive and primed. A meta-analysis identified genes expressed exclusively in the inner cell mass and in the naive but not in the primed pluripotent state. We propose these as additional biomarkers defining naive PSCs.This article is part of the theme issue 'Designer human tissue: coming to a lab near you'.

Clinical development of targeted and immune based anti-cancer therapies

Cancer is currently the second leading cause of death globally and is expected to be responsible for approximately 9.6 million deaths in 2018. With an unprecedented understanding of the molecular pathways that drive the development and progression of human cancers, novel targeted therapies have become an exciting new development for anti-cancer medicine. These targeted therapies, also known as biologic therapies, have become a major modality of medical treatment, by acting to block the growth of cancer cells by specifically targeting molecules required for cell growth and tumorigenesis. Due to their specificity, these new therapies are expected to have better efficacy and limited adverse side effects when compared with other treatment options, including hormonal and cytotoxic therapies. In this review, we explore the clinical development, successes and challenges facing targeted anti-cancer therapies, including both small molecule inhibitors and antibody targeted therapies. Herein, we introduce targeted therapies to epidermal growth factor receptor (EGFR), vascular endothelial growth factor (VEGF), human epidermal growth factor receptor 2 (HER2), anaplastic lymphoma kinase (ALK), BRAF, and the inhibitors of the T-cell mediated immune response, cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) and programmed cell death protein-1 (PD-1)/ PD-1 ligand (PD-1 L).

Novel Cellularly Active Inhibitor Regresses DDAH1 Induced Prostate Tumor Growth by Restraining Tumor Angiogenesis through Targeting DDAH1/ADMA/NOS Pathway

Dimethylarginine dimethylaminohydrolase1 (DDAH1) inhibitors are important therapeutics by virtue of their ability to control nitric oxide (NO) production by elevating asymmetric dimethylarginine (ADMA) levels. In a screening campaign, we identified that DD1E5 (3-amino-6- tert-butyl-N-(1,3-thiazol-2-yl)-4-(trifluoromethyl)thieno[2,3- b]pyridine-2- carboxamide) inhibits the DDAH1 activity both in vitro and in cultured cells. Mechanistic studies found that DD1E5 is a competitive inhibitor (dissociation constant ( K_i) of 2.05 ± 0.15 μM). Enzyme kinetic assays showed time and concentration dependent inhibition of DDAH1 with DD1E5, which shows tight binding with an inactivation rate constant of 0.2756 ± 0.015 M^-1 S^-1. Treatment of cancer cells with DDAH1 inhibitors shows inhibition of cell proliferation and a subsequent decrease in NO production with ADMA accumulation. DD1E5 reversed the elevated VEGF, c-Myc, HIF-1α, and iNOS levels induced by exogenous DDAH1 overexpression in PCa cells. Moreover, DD1E5 significantly increased intracellular levels of ADMA and reduced NO production, suggesting its therapeutic potential for cancers in which DDAH1 is upregulated. In in vitro assays, DD1E5 abrogated the secretion of angiogenic factors (bFGF and IL-8) into conditional media, indicating its antiangiogenic potential. DD1E5 inhibited in vivo growth of xenograft tumors derived from PCa cells with DDAH1 overexpression, by reducing tumor endothelial content represented with low CD31 expression. VEGF, HIF-1α, and iNOS expression were reversed in DD1E5 treated tumors compared to respective control tumors. In this work, integrating multiple approaches shows DD1E5 is a promising tool for the study of methylarginine-mediated NO control and a potential therapeutic lead compound against pathological conditions with elevated NO production such as cancers and other diseases.

Structure-based modification of carbonyl-diphenylpyrimidines (Car-DPPYs) as a novel focal adhesion kinase (FAK) inhibitor against various stubborn cancer cells

A family of carbonyl-substituted diphenylpyrimidine derivatives (Car-DPPYs) with strong activity against focal adhesion kinase (FAK), were described in this manuscript. Among them, compounds 7a (IC₅₀ = 5.17 nM) and 7f (IC₅₀ = 2.58 nM) displayed equal anti-FAK enzymatic activity to the lead compound TAE226 (6.79 nM). In particular, compound 7a also exhibited strong antiproliferative activity against several stubborn cancer cells, including AsPC-1 cells (IC₅₀ = 0.105 μM), BxPC-3 cells (IC₅₀ = 0.090 μM), and MCF-7/ADR cells (IC₅₀ = 0.59 μM). Additionally, compound 7a also showed great antitumor efficacy in vivo via aAsPC-1 cancer Xenograft mouse model. The preliminary mechanism study by Western blot analysis revealed that 7a repressed FAK phosphorylation in AsPC cancer cells. Taken together, the results indicate that compound 7a may serve as a promising preclinical candidate for treatment of stubborn cancers.

Tumor microenvironment-driven non-cell-autonomous resistance to antineoplastic treatment

Drug resistance is of great concern in cancer treatment because most effective drugs are limited by the development of resistance following some periods of therapeutic administration. The tumor microenvironment (TME), which includes various types of cells and extracellular components, mediates tumor progression and affects treatment efficacy. TME-mediated drug resistance is associated with tumor cells and their pericellular matrix. Noninherent-adaptive drug resistance refers to a non-cell-autonomous mechanism in which the resistance lies in the treatment process rather than genetic or epigenetic changes, and this mechanism is closely related to the TME. A new concept is therefore proposed in which tumor cell resistance to targeted therapy may be due to non-cell-autonomous mechanisms. However, knowledge of non-cell-autonomous mechanisms of resistance to different treatments is not comprehensive. In this review, we outlined TME factors and molecular events involved in the regulation of non-cell-autonomous resistance of cancer, summarized how the TME contributes to non-cell-autonomous drug resistance in different types of antineoplastic treatment, and discussed the novel strategies to investigate and overcome the non-cell-autonomous mechanism of cancer non-cell-autonomous resistance.

Discovery and synthesis of 2-amino-1-methyl-1H-imidazol-4(5H)-ones as GPCR ligands; an approach to develop breast cancer drugs via GPCR associated PAR1 and PI3Kinase inhibition mechanism

Efforts were taken to synthesis and characterize 2-amino-1-methyl-1H-imidazole-4(5H)-one derivatives (4a-u) through a four-step reaction. The achieved compounds in remarkable yield have characterized through standard analytical techniques such as FTIR, LC-MS, NMR, HRMS, and elemental analysis. Present study mainly aimed to evaluate 4a-u as G protein-coupled receptors (GPCR). In the mechanism, stimulation of phosphoinositide 3-kinase (PI3K) and Akt (protein kinase B) is a general reaction activated by a series of membrane-bound receptors such as GPCR. Protease-activated receptor-1 (PAR1) is a subfamily of related GPCR, which triggered by the division of fragment of its extracellular domain. Therefore, molecular docking is done to ensure the inhibition of PAR1 and PI3Kinase. PI3Kinase is a chief enzyme in the development of breast cancer via the Akt/mTOR pathway. Thus, in vitro PI3Kinase inhibition and anti-breast cancer studies has also done to screen medicinally important compounds among (4a-u). Based on the best binding affinity, in vitro relative % activity and IC₅₀ values, compounds 4a, 4g, 4i, 4n, and 4u were screened for further preclinical studies in animal model evaluations.

Antisense Oligonucleotides Targeting Angiogenic Factors as Potential Cancer Therapeutics

Cancer is one of the leading causes of death worldwide, and conventional cancer therapies such as surgery, chemotherapy, and radiotherapy do not address the underlying molecular pathologies, leading to inadequate treatment and tumor recurrence. Angiogenic factors, such as EGF, PDGF, bFGF, TGF-β, TGF-α, VEGF, endoglin, and angiopoietins, play important roles in regulating tumor development and metastasis, and they serve as potential targets for developing cancer therapeutics. Nucleic acid-based therapeutic strategies have received significant attention in the last two decades, and antisense oligonucleotide-mediated intervention is a prominent therapeutic approach for targeted manipulation of gene expression. Clinical benefits of antisense oligonucleotides have been recognized by the U.S. Food and Drug Administration, with full or conditional approval of Vitravene, Kynamro, Exondys51, and Spinraza. Herein we review the scope of antisense oligonucleotides that target angiogenic factors toward tackling solid cancers.

New clinical trial designs in the era of precision medicine

Cancer treatment has made significant strides towards the promise of personalized medicine. Recent scientific advances have shown that there are numerous genetic deregulations that are common in multiple cancer types, raising the possibility of developing drugs targeting those deregulations irrespective of the tumour type. Precision Cancer Medicine (PCM) was born out of accumulated evidence matching targeted agents with these tumour molecular deregulations. At the same time, the therapeutic armamentarium is rapidly increasing and the number of new drugs (including immune-oncology agents) entering drug development continues to rise. These factors, added to strong collaboration with regulatory agencies, which have approved novel agents based on data obtained from phase 1/2 trials, have led to unprecedented evolution in the design of early-stage clinical trials. Currently, we have seen rapid phase 1 dose-escalation trials followed by remarkably large expansion cohorts, and are witnessing the emergence of new trials, such as adaptive studies with basket and umbrella designs aimed at optimizing the biomarker-drug co-development process. Alongside the growing complexity of these clinical trials, new frameworks for stronger and faster collaboration between all stakeholders in drug development, including academic institutions and frameworks, clinicians, pharma companies and regulatory agencies, have been established. In this review article, we describe the main challenges and opportunities that these new trial designs may provide for a more efficient drug development process, which may ultimately help ensure that PCM becomes a reality for patients.

Circulating Tumour Cells in Predictive Molecular Pathology: Focus on Drug-Sensitive Assays and 3D Culture

Molecular cytopathology is a rapidly evolving field of cytopathology that provides biological information about the response to personalised therapy and about the prognosis of neoplasms diagnosed on cytological samples. Biomarkers such as circulating tumour cells and circulating tumour DNA are increasingly being evaluated in blood and in other body fluids. Such liquid biopsies are non-invasive, repeatable, and feasible also in patients with severe comorbidities. However, liquid biopsy may be challenging due to a low concentration of biomarkers. In such cases, biomarkers can be detected with highly sensitive molecular techniques, which in turn should be validated and integrated in a complex algorithm that includes tissue-based molecular assessments. The aim of this review is to provide the cytopathologist with practical information that is relevant to daily practice, particularly regarding the emerging role of circulating tumour cells in the field of predictive molecular pathology.