Potent Cyclin-dependent Kinase Research Articles

Novel Fused Pyrimidines as Potent Cyclin-Dependent Kinases Inhibitor for Gastric Adenocarcinoma: Combined InVitro, In Silico Anticancer Studies.

Our research aims to design novel pyrimidine derivatives inspired by the common pyrimidine core found in many FDA-approved drugs. However, extensive prior research on the pyrimidine scaffold has made discovering new molecules more challenging. To overcome this obstacle, we employed a molecular hybridisation strategy, opting to hybridise tetralin and pyrimidine, recognising their potential in cancer therapeutics. The fused pyrimidine was synthesised through a base-mediated condensation of chalcone with amidine. The reaction conditions were further optimised for base, solvent, temperature and time to produce a series of 21 novel derivatives. These compounds were subsequently screened for anticancer activity against gastric adenocarcinoma cell lines using the MTT assay. Among the synthesised compounds, 2-(pyridin-3-yl)-4-(pyridin-3-yl)-5,6-dihydrobenzo[h]quinazoline 8b and 4-(2-(pyridin-3-yl)-5,6 dihydrobenzo[h]quinazolin-4-yl) phenol 5g exhibited potent anticancer activity compared to (R)-Roscovitine. Additionally, a molecular docking study was conducted to assess the reactivity of compound 5g, revealing that the presence of a phenolic hydroxyl group enables hydrogen bonding with CDKs and enhances anticancer activity. Furthermore, the efficacy of compound 5g was validated through an invitro CDK2/cyclin A2 enzyme inhibition assay. Interestingly, the observed CDK2 inhibitory activity showed a good correlation with the corresponding value for the antiproliferative activity of the tested compounds.

Strategy to Improve the Oral Pharmacokinetics of Cyclin-Dependent Kinase 4/6 Inhibitors: Enhancing Permeability and CYP450 Inhibition by a Natural Bioenhancer

Palbociclib and ribociclib an orally bioavailable, potent cyclin-dependent kinase 4/6 inhibitors, with low oral bioavailability due to substrate specificity towards CYP3A and P-glycoprotein. Thus, current research aims to examine the effect of a bioenhancer (naringin), on oral pharmacokinetics of palbociclib and ribociclib. Naringin’s affinity for CYP3A4 and P-glycoprotein was studied using molecular docking; its impact on palbociclib/ribociclib CYP3A metabolism and P-glycoprotein-mediated efflux was examined using in vitro preclinical models; and its oral pharmacokinetics in rats were assessed following oral administration of palbociclib/ribociclib in presence of naringin (50 and 100 mg/kg). Naringin binds optimally to both proteins with the highest net binding energy of − 1477.23 and − 1607.47 kcal/mol, respectively. The microsomal intrinsic clearance of palbociclib and ribociclib was noticeably reduced by naringin (5–100 µM), by 3.0 and 2.46-folds, respectively. Similarly, naringin had considerable impact on the intestinal transport and efflux of both drugs. The pre-treatment with 100 mg/kg naringin increased significantly (p < 0.05) the oral exposure of palbociclib (2.0-fold) and ribociclib (1.95-fold). Naringin's concurrent administration of palbociclib and ribociclib increased their oral bioavailability due to its dual inhibitory effect on CYP3A4 and P-glycoprotein; thus, concurrent naringin administration may represent an innovative strategy for enhancing bioavailability of cyclin-dependent kinase inhibitors.Graphical

Novel meriolin derivatives potently inhibit cell cycle progression and transcription in leukemia and lymphoma cells via inhibition of cyclin-dependent kinases (CDKs)

A key feature of cancer is the disruption of cell cycle regulation, which is characterized by the selective and abnormal activation of cyclin-dependent kinases (CDKs). Consequently, targeting CDKs via meriolins represents an attractive therapeutic approach for cancer therapy. Meriolins represent a semisynthetic compound class derived from meridianins and variolins with a known CDK inhibitory potential. Here, we analyzed the two novel derivatives meriolin 16 and meriolin 36 in comparison to other potent CDK inhibitors and could show that they displayed a high cytotoxic potential in different lymphoma and leukemia cell lines as well as in primary patient-derived lymphoma and leukemia cells. In a kinome screen, we showed that meriolin 16 and 36 prevalently inhibited most of the CDKs (such as CDK1, 2, 3, 5, 7, 8, 9, 12, 13, 16, 17, 18, 19, 20). In drug-to-target modeling studies, we predicted a common binding mode of meriolin 16 and 36 to the ATP-pocket of CDK2 and an additional flipped binding for meriolin 36. We could show that cell cycle progression and proliferation were blocked by abolishing phosphorylation of retinoblastoma protein (a major target of CDK2) at Ser612 and Thr82. Moreover, meriolin 16 prevented the CDK9-mediated phosphorylation of RNA polymerase II at Ser2 which is crucial for transcription initiation. This renders both meriolin derivatives as valuable anticancer drugs as they target three different Achilles’ heels of the tumor: (1) inhibition of cell cycle progression and proliferation, (2) prevention of transcription, and (3) induction of cell death.

Discovery of a Novel and Potent Cyclin-Dependent Kinase 8/19 (CDK8/19) Inhibitor for the Treatment of Cancer.

The mediator kinases CDK8 and CDK19 control the dynamic transcription of selected genes in response to various signals and have been shown to be hijacked to sustain hyperproliferation by various solid and liquid tumors. CDK8/19 is emerging as a promising anticancer therapeutic target. Here, we report the discovery of compound 12, a novel small molecule CDK8/19 inhibitor. This molecule demonstrated not only decent enzymatic and cellular activities but also remarkable selectivity in CDK and kinome panels. Besides, compound 12 also displayed favorable ADME profiles including low CYP1A2 inhibition, acceptable clearance, and high oral bioavailability in multiple preclinical species. Robust in vivo PD and efficacy studies in mice models further demonstrated its potential use as mono- and combination therapy for the treatment of cancers.

Discovery of novel macrocyclic derivatives as potent and selective cyclin-dependent kinase 2 inhibitors

Cyclin-dependent kinase 2 (CDK2) is a member of CDK family of kinases (CDKs) that regulate the cell cycle. Its inopportune or over-activation leads to uncontrolled cell cycle progression and drives numerous types of cancers, especially ovarian, uterine, gastric cancer, as well as those associated with amplified CCNE1 gene. However, developing selective lead compound as CDK2 inhibitors remains challenging owing to similarities in the ATP pockets among different CDKs. Herein, we described the optimization of compound 1, a novel macrocyclic inhibitor targeting CDK2/5/7/9, aiming to discover more selective and metabolically stable lead compound as CDK2 inhibitor. Molecular dynamic (MD) simulations were performed for compound 1 and 9 to gain insights into the improved selectivity against CDK5. Further optimization efforts led to compound 22, exhibiting excellent CDK2 inhibitory activity, good selectivity over other CDKs and potent cellular effects. Based on these characterizations, we propose that compound 22 holds great promise as a potential lead candidate for drug development.

Abstract 7094: Clinical metabolomics reveals baseline biomarkers of hepatic dysfunction correlating with irregular drug-induced ALT and bilirubin elevations

Abstract AZD4573 is a highly potent and selective Cyclin-Dependent Kinase 9 inhibitor. The AZD4573 First-in-Human (FIH) study revealed variable alanine transaminase (ALT) and/or bilirubin elevation and a clear correlation to dose or PK exposure could not be defined. While concurrent ALT elevation ≥3x upper limit of normal (ULN) and bilirubin elevation ≥2x ULN (potential Hy’s law) is a biochemical finding indicating potential drug-induced liver injury, quantitative modeling disconnected ALT and bilirubin elevation demonstrating that the observations were not Hy’s Law cases. Furthermore, we implemented a targeted metabolomics workflow to investigate the ALT and bilirubin elevation mechanism and identify predictive biomarkers to better understand and/or predict any hepatic stress liabilities associated with AZD4573 clinical development. We implemented an established metabolomics methodology to 359 samples from 15 patients yielding 47,000 total data points. Data was separated into 98 different dosing intervals from the 15 patients to identify the ALT and bilirubin-associated metabolic changes conserved across all patients while incorporating metabolic differences in individual patents with ALT and bilirubin elevation in only a fraction of multiple doses. Orthogonal Partial Least Squares modeling identified several metabolites and pathways altered as a function of maximum ALT or bilirubin levels. Post-dose conjugated bile acids were elevated when ALT and bilirubin were elevated. Pre-dose creatine levels were decreased when ALT and bilirubin elevation occurred, and pre-dose glutamate levels were elevated when ALT elevation occurred. Pre-dose decreased total carnitines and kynurenine pathway activation were observed when ALT and bilirubin elevation occurred, but the effect did not reach statistical significance. Elevated bile acids are an established characteristic of cholestasis and suggest cholestasis as a probable mechanism for AZD4573-induced reversible liver stress. Interestingly, decreased creatine, glutamate elevation, decreased total carnitine, and kynurenine pathway activation are all associated with some form of liver stress or disfunction which may explain the irregular ALT and bilirubin elevations observed in patients receiving AZD4573; while ALT itself is a biomarker of liver damage, these pre-dose biochemical changes may illuminate potential preceding liver stress. Dosing patients already experiencing higher liver stress levels may be more susceptible to drug-induced ALT and bilirubin elevation, and patients with increasing in-study liver stress may only present at later doses. This work demonstrates metabolomics utility to elucidate possible mechanisms of liver toxicity as well as to identify potential predictive biomarkers for further investigation to explore individual patient risk in clinical studies. Citation Format: John K. Meissen, Kevin Contrepois, Sophie Regan, Jennifer Tan, Alison J. Foster, Jiaqi Yuan, Shringi Sharma, Dominic Williams, Anton I. Rosenbaum. Clinical metabolomics reveals baseline biomarkers of hepatic dysfunction correlating with irregular drug-induced ALT and bilirubin elevations [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7094.

P21 as a Predictor and Prognostic Indicator of Clinical Outcome in Rectal Cancer Patients.

The cell cycle plays a key and complex role in the development of human cancers. p21 is a potent cyclin-dependent kinase inhibitor (CDKI) involved in the promotion of cell cycle arrest and the regulation of cellular senescence. Altered p21 expression in rectal cancer cells may affect tumor cells' behavior and resistance to neoadjuvant and adjuvant therapy. Our study aimed to ascertain the relationship between the differential expression of p21 in rectal cancer and patient survival outcomes. Using tissue microarrays, 266 rectal cancer specimens were immunohistochemically stained for p21. The expression patterns were scored separately in cancer cells retrieved from the center and the periphery of the tumor; compared with clinicopathological data, tumor regression grade (TRG), disease-free, and overall survival. Negative p21 expression in tumor periphery cells was significantly associated with longer overall survival upon the univariate (p = 0.001) and multivariable analysis (p = 0.003, HR = 2.068). Negative p21 expression in tumor periphery cells was also associated with longer disease-free survival in the multivariable analysis (p = 0.040, HR = 1.769). Longer overall survival times also correlated with lower tumor grades (p= 0.011), the absence of vascular and perineural invasion (p = 0.001; p < 0.005), the absence of metastases (p < 0.005), and adjuvant treatment (p = 0.009). p21 expression is a potential predictive and prognostic biomarker for clinical outcomes in rectal cancer patients. Negative p21 expression in tumor periphery cells demonstrated significant association with longer overall survival and disease-free survival. Larger prospective studies are warranted to investigate the ability of p21 to identify rectal cancer patients who will benefit from neoadjuvant and adjuvant therapy.

Antioxidant, Anti-Inflammatory, Antimicrobial, and Anticancer Activities of Pomegranate Juice Concentrate.

Pomegranate juice concentrate (PJC) is a rich source of polyphenols, which exhibit significant antioxidant activity and potential health benefits for disease prevention and therapy. In this study, the polyphenolic profile of PJC was investigated for the first time, and it was found that PJC can inhibit oxidative damage to bovine serum albumin (BSA) and deoxyribonucleic acid (DNA), as well as acetylcholinesterase, α-amylase, and tyrosinase activities. The primary polyphenols identified in PJC were 4-Hydroxy-3-Methoxybenzoate, epicatechin, catechin, rutin, ferulic acid, P-coumaric acid, and cinnamic acid. Additionally, PJC demonstrated potent antibacterial effects against human pathogens such as Streptococcus mutans and Aeromonas hydrophila and dose-dependently reduced the proliferation of colorectal, breast, and hepatic cancer cells via apoptosis. Furthermore, PJC blocked B-cell lymphoma 2 (BCl-2) and the expression of a potent cyclin-dependent kinase inhibitor (P21) and enhanced tumor protein (P53) expression, compared to both untreated cells and cells treated with fluoropyrimidine 5-fluorouracil (5-FU). As a result, PJC may be a beneficial ingredient in the formulation of emerging natural-compound-based chemotherapy and functional foods and could be utilized by the food, nutraceutical, and pharmaceutical industries.

Synthesis and biological evaluation of novel pteridin-7(8H)-one derivatives as potent CDK2 inhibitors

Cyclin-dependent kinase 2 (CDK2) is considered as an important target in the research of antitumor drugs. Taking the CDK2/4/6 inhibitor Ebvaciclib as the positive control and an in-house library compound (23) as the lead compound, three classes of 30 target compounds with pteridin-7(8H)-one as the core structure were designed to establish structure–activity relationships (SAR). In general, SAR of pteridin-7(8H)-one CDK2 inhibitors is systematically described in this paper, resulting in the discovery of two compounds (KII-17 and KII-21) with further research value. After the above compounds were tested for CDK2/4/6 kinase selectivity, we found that compound KII-21 was about 3 and 4 times more selective to CDK2-cyclinE2 than CDK4-cyclinD1 and CDK6-cyclinD3, respectively. This work also provides a reference basis for the subsequent research on CDK2 inhibitors.

Abstract 5994: INX-315, a potent and selective CDK2 inhibitor, demonstrates robust antitumor activity in CCNE1-amplified cancers

Abstract Cyclin-dependent kinases (CDK) are a family of serine/threonine kinases that heterodimerize with regulatory subunits called cyclins to drive cell cycle progression. Uncontrolled cellular proliferation is a hallmark of cancer commonly driven by dysregulated kinase activity of specific CDK family members, including cyclin-dependent kinase 2 (CDK2). Aberrant CDK2 activity most frequently occurs through amplification of CCNE1 and/or overexpression of its protein product cyclin E1, which is a canonical binding partner of CDK2. Overexpression of cyclin E1 is observed in many solid tumors including in patients with high grade serous ovarian cancer (HGSOC), gastric cancer, and ER-positive breast cancer patients whose tumors have progressed on a prior CDK4/6 inhibitor regimen. Selective inhibition of CDK2 is thus a compelling therapeutic approach to regain cell cycle control. Here, we report preclinical data supporting the development of INX-315 for patients with cancers in which proliferation is CDK2-dependent. INX-315 is a potent inhibitor of CDK2/cyclin E (0.6 nM biochemical IC50) with high selectivity over other CDK family members in both biochemical and intracellular NanoBRET assays. In CCNE1-amplified human ovarian and gastric cancer cell lines, INX-315 potently inhibited Rb phosphorylation, induced a G1 cell cycle arrest, and inhibited proliferation. INX-315 also showed potent anti-proliferative activity in luminal breast cancer cell lines that had been cultured in CDK4/6 inhibitor (+/- anti-estrogen therapy) for prolonged periods to the point of developing drug resistance. While these cell lines did not readily respond to either CDK4/6 or CDK2 inhibition alone, combination treatment again suppressed Rb phosphorylation, accompanied by G1 arrest and a senescent-like phenotype. Lastly, in CCNE1-amplified xenograft models of ovarian and gastric carcinomas, INX-315 inhibited Rb-phosphorylation and induced tumor regression. These data demonstrate INX-315 to be a potent and selective CDK2 inhibitor that may benefit patients with CDK2/cyclin E driven cancers. Citation Format: Alec G. Trub, John E. Bisi, Catherine Dietrich, Michael Taylor, Jay C. Strum, Shom Goel, Patrick J. Roberts. INX-315, a potent and selective CDK2 inhibitor, demonstrates robust antitumor activity in CCNE1-amplified cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5994.

Discovery of N,4-Di(1H-pyrazol-4-yl)pyrimidin-2-amine-Derived CDK2 Inhibitors as Potential Anticancer Agents: Design, Synthesis, and Evaluation.

Cyclin-dependent kinase 2 (CDK2) has been garnering considerable interest as a target to develop new cancer treatments and to ameliorate resistance to CDK4/6 inhibitors. However, a selective CDK2 inhibitor has yet to be clinically approved. With the desire to discover novel, potent, and selective CDK2 inhibitors, the phenylsulfonamide moiety of our previous lead compound 1 was bioisosterically replaced with pyrazole derivatives, affording a novel series of N,4-di(1H-pyrazol-4-yl)pyrimidin-2-amines that exhibited potent CDK2 inhibitory activity. Among them, 15 was the most potent CDK2 inhibitor (Ki = 0.005 µM) with a degree of selectivity over other CDKs tested. Meanwhile, this compound displayed sub-micromolar antiproliferative activity against a panel of 13 cancer cell lines (GI50 = 0.127-0.560 μM). Mechanistic studies in ovarian cancer cells revealed that 15 reduced the phosphorylation of retinoblastoma at Thr821, arrested cells at the S and G2/M phases, and induced apoptosis. These results accentuate the potential of the N,4-di(1H-pyrazol-4-yl)pyrimidin-2-amine scaffold to be developed into potent and selective CDK2 inhibitors for the treatment of cancer.

MORC4 plays a tumor-promoting role in colorectal cancer via regulating PCGF1/CDKN1A axis in vitro and in vivo.

MORC family CW-type zinc finger 4 (MORC4) possessing nuclear matrix binding domains has been observed to be involved in multiple cancer development. By digging three gene expression omnibus (GEO) gene microarrays (GSE110223, GSE110224 and GSE24514), we found that MORC4 was overexpressed in colorectal cancer (CRC) samples (log2 Fold change >1, p < 0.05). We aimed to investigate the role of MORC4 in CRC malignant behaviors, with an emphasis on polycomb group ring finger 1 (PCGF1)/cyclin-dependent kinase inhibitor 1A (CDKN1A) axis. Firstly, we confirmed MORC4 as an upregulated gene in 60 pairs of frozen CRC and adjacent normal samples. MORC4 overexpression increased proliferation and metastasis, and decreased apoptosis in SW480 and HT29 cells, which was diminished by the knockdown of PCGF1, a transcriptional repressor of CDKN1A (a potent cyclin-dependent kinase inhibitor). MORC4 was further identified as a novel molecule that interacted with PCGF1 via coimmunoprecipitation. MORC4 itself did not substantially suppress CDKN1A transcriptional activity, but it augmented PCGF1's effect on CDKN1A. Additionally, MORC4 acted as the substrate of HECT, C2, and WW domain-containing E3 ubiquitin protein ligase 2 (HECW2) and was degraded through ubiquitin-proteasome system. Collectively, our work suggested that MORC4 accelerated CRC progression via governing PCGF1/CDKN1A signaling.

Development and Validation of a Rapid LC-MS/MS Method for Quantifying Alvocidib: In Silico and In Vitro Metabolic Stability Estimation in Human Liver Microsomes

Alvocidib (AVC; flavopiridol) is a potent cyclin-dependent kinase inhibitor used in patients with acute myeloid leukemia (AML). The FDA has approved orphan drug designation to AVC for treating patients with AML. In the current work, the in silico calculation of AVC metabolic lability was done using the P450 metabolism module of the StarDrop software package, that is expressed as a composite site lability (CSL). This was followed by establishing an LC-MS/MS analytical method for AVC estimation in human liver microsomes (HLMs) to assess metabolic stability. AVC and glasdegib (GSB), used as internal standards (IS), were separated utilizing a C18 column (reversed chromatography) with an isocratic mobile phase. The lower limit of quantification (LLOQ) was 5.0 ng/mL, revealing the sensitivity of the established LC-MS/MS analytical method that exhibited a linearity in the range 5-500 ng/mL in the HLMs matrix with correlation coefficient (R2 = 0.9995). The interday and intraday accuracy and precision of the established LC-MS/MS analytical method were -1.4% to 6.7% and -0.8% to 6.4%, respectively, confirming the reproducibility of the LC-MS/MS analytical method. The calculated metabolic stability parameters were intrinsic clearance (CLint) and in vitro half-life (t1/2) of AVC at 26.9 µL/min/mg and 25.8 min, respectively. The in silico results from the P450 metabolism model matched the results generated from in vitro metabolic incubations; therefore, the in silico software can be used to predict the metabolic stability of the drugs, saving time and resources. AVC exhibits a moderate extraction ratio, indicating reasonable in vivo bioavailability. The established chromatographic methodology was the first LC-MS/MS method designed for AVC estimation in HLMs matrix that was applied for AVC metabolic stability estimation.

Development of Potent and Selective Dual Cyclin-Dependent Kinase 7 and 9 Inhibitors

Development of Potent and Selective Dual Cyclin-Dependent Kinase 7 and 9 Inhibitors

2-Anilino-4-(1-methyl-1H-pyrazol-4-yl)pyrimidine-derived CDK2 inhibitors as anticancer agents: Design, synthesis & evaluation

Deregulation of cyclin-dependent kinase 2 (CDK2) and its activating partners, cyclins A and E, is associated with the pathogenesis of a myriad of human cancers and with resistance to anticancer drugs including CDK4/6 inhibitors. Thus, CDK2 has become an attractive target for the development of new anticancer therapies and for the amelioration of the resistance to CDK4/6 inhibitors. Bioisosteric replacement of the thiazole moiety of CDKI-73, a clinically trialled CDK inhibitor, by a pyrazole group afforded 9 and 19 that displayed potent CDK2-cyclin E inhibition (Ki = 0.023 and 0.001 μM, respectively) with submicromolar antiproliferative activity against a panel of cancer cell lines (GI50 = 0.025–0.780 μM). Mechanistic studies on 19 with HCT-116 colorectal cancer cells revealed that the compound reduced the phosphorylation of retinoblastoma at Ser807/811, arrested the cells at the G2/M phase, and induced apoptosis. These results highlight the potential of the 2-anilino-4-(1-methyl-1H-pyrazol-4-yl)pyrimidine series in developing potent and selective CDK2 inhibitors to combat cancer.

Discovery of Novel N-(5-(Pyridin-3-yl)-1H-indazol-3-yl)benzamide Derivatives as Potent Cyclin-Dependent Kinase 7 Inhibitors for the Treatment of Autosomal Dominant Polycystic Kidney Disease.

Recent evidence suggests that CDK7 is a novel potential drug target for autosomal dominant polycystic kidney disease (ADPKD) treatment. Herein, on the basis of structural analysis, a hit compound 3 with a novel scaffold was designed and subsequent medicinal chemistry efforts by a rational design strategy were conducted to improve CDK7 inhibitors' potency and selectivity. The representative compound B2 potently inhibited CDK7 with an IC50 value of 4 nM and showed high selectivity over CDKs. Compound B2 showed high potency to inhibit cyst growth and exhibited lower cytotoxicity than THZ1 in an in vitro Madin-Darby canine kidney cyst model. In addition, compound B2 was also highly efficacious in suppressing renal cyst development in an ex vivo embryonic kidney cyst model and in vivo ADPKD mouse model. These results indicate that compound B2 represents a promising lead compound that deserves further investigation to discover novel therapeutic agents for ADPKD.

220 (PB100) - Discovery of INCB123667, a potent and selective cyclin-dependent kinase 2 (CDK2) inhibitor for the treatment of cyclin E dysregulated cancers

Background: Dysregulation of the CDK/cyclin complex causes aberrant cell cycle entry and progression that can lead to cancer. For instance, the CDK2/ cyclin E complex governs the G1-S transition and overexpression of cyclin E has been associated with ovarian and breast cancers. Our initial studies have demonstrated that genetic depletion of CDK2 inhibits cell growth and survival in cancer cells overexpressing cyclin E. Furthermore, inhibition of CDK2 may be effective in cancers resistant to clinically approved CDK4/6 therapies as increased CDK2/cyclin E activity has been reported as a compensatory mechanism.

Comparative binding affinity analysis of dual CDK2/FLT3 inhibitors

AbstractSelective inhibition of cyclin‐dependent kinase 2 (CDK2) using small molecules is gaining popularity for the treatment of certain types of acute myeloid leukemia (AML). In this study, we used different molecular modeling techniques to investigate the structure–activity relationship (SAR) and binding modalities of dual CDK2/FLT3 inhibitors. The key chemical characteristics of the 3H‐pyrazolo[4,3‐f]quinoline derivatives were highlighted as descriptive colored contours using comparative molecular similarity analysis (CoMSIA). Modifying chemical groups in existing compounds along these contours could improve CDK2 selectivity over FMS‐like tyrosine kinase 3 (FLT3). We determined the ligand affinities for CDK2 by estimating the binding free energy using molecular mechanics generalized Born surface area (MM‐GBSA) and umbrella sampling (US) simulations. Reasonable correlations were found between the computed and experimental binding energies, suggesting that MM‐GBSA and US can be used to reliably predict the binding affinities of new compounds in the more potent CDK2 drug development process.

Pulmonary Delivery of Extracellular Vesicle-Encapsulated Dinaciclib as an Effective Lung Cancer Therapy.

Simple SummaryThe clinical outcomes of lung cancer remain poor. The targeted delivery of treatment and the implementation of a method to overcome drug resistance are essential for the improvement of cancer therapy. The aim of our study was to assess the treatment effectiveness of engineered extracellular vesicles (EV) carrying both dinaciclib, a potent CDK inhibitor, and the proapoptotic factor TRAIL for a combinatorial lung cancer therapy. We showed that the engineered complexed EV agent, EV-T-Dina, was stable both in vitro and in vivo. Importantly, EV-T-Dina can overcome the drug-resistance of lung cancer cells, and when nebulized and administered by the pulmonary route, it demonstrated high efficacy and satisfactory safety for the treatment of lung cancers. The underlying mechanism for the synergistic killing of cancer cells by dinaciclib and TRAIL was associated with the concomitant downregulation of the anti-apoptotic factors cFLIP, MCL-1, and Survivin. Thus, the aerosolized EV-T-Dina potentially constitutes a novel and effective therapy for lung cancers.The clinical outcomes of lung cancer remain poor, mainly due to the chemoresistance and low bioavailability of systemically delivered drugs. Therefore, novel therapeutic strategies are urgently needed. The TNF-related apoptosis-inducing ligand (TRAIL)-armed extracellular vesicle (EV-T) has proven to be highly synergistic for the killing of cancer cells with the potent cyclin-dependent kinase (CDK) inhibitor Dinaciclib (Dina). However, both optimal drug formulations and delivery strategies are yet to be established to facilitate the clinical application of the combination of EV-T and Dina. We hypothesize that Dina can be encapsulated into EV-T to produce a complexed formulation, designated EV-T-Dina, which can be nebulized for pulmonary delivery to treat lung cancer with potentially improved efficacy and safety. The prepared EV-T-Dina shows good stability both in vitro and in vivo and is very efficient at killing two highly TRAIL-resistant cancer lines. The ability to overcome TRAIL resistance is associated with the concomitant downregulation of the expression of cFLIP, MCL-1, and Survivin by Dina. The EV-T-Dina solution is nebulized for inhalation, showing unique deposition in animal lungs and importantly it demonstrates a significant suppression of the growth of orthotopic A549 tumors without any detectable adverse side events. In conclusion, the aerosolized EV-T-Dina constitutes a novel therapy, which is highly effective and safe for the treatment of lung cancers.

Discovery of novel tacrine derivatives as potent antiproliferative agents with CDKs inhibitory property

Tacrine was the first approved drug by the FDA for the treatment of Alzheimer’s disease (AD) but was withdrawn from the market due to its dose-dependent hepatotoxicity. Herein, we describe our efforts toward the discovery of a novel series of tacrine derivatives for cancer therapeutics. Intensive structural modifications of tacrine led to the identification of N-(4-{9-[(3S)-3-aminopyrrolidin-1-yl]-5,6,7,8-tetrahydroacridin-2-yl}pyridin-2-yl)cyclopropanecarboxamide hydrochloride ((S)-45, ZLWT-37) as a potent antiproliferative agent (GI50 = 0.029 μM for HCT116). In addition, ZLWT-37 exhibited lower inhibitory activity against acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) compared to tacrine. The in vitro studies demonstrated that ZLWT-37 could significantly induce apoptosis and arrest the cell cycle in the G2/M phase in HCT116 cells. The in vivo studies revealed that compound ZLWT-37 showed excellent antitumor efficacy in HCT116 xenograft tumor model and favorable pharmacokinetics profiles (F% = 28.70%) as well as low toxicity in the acute toxicity test with a median lethal dose (LD50) of 380.3 mg/kg. Encouragingly, ZLWT-37 had no obvious hepatotoxicity, nephrotoxicity, and hematologic toxicity. Kinase assay suggested that ZLWT-37 possessed potent cyclin-dependent kinase 9 (CDK9) inhibitory activity (IC50 = 0.002 μM) and good selectivity over CDK2 (IC50 = 0.054 μM). Collectively, these findings indicate that compound ZLWT-37 is a promising anti-cancer agent that deserves further preclinical evaluation.