Clinical benefit and safety profile of cross-line therapy with CDK4/6 inhibitors:a retrospective study of HR+/HER2–advanced breast cancer

Objective:CDK4/6 inhibitors(CDK4/6is)in combination with endocrine therapy have secured a central role in the treatment of hormone receptor(HR)-positive advanced breast cancer(ABC)and have transformed the therapeutic landscape.Cross-line CDK4/6i therapy in which another CDK4/6i is continued after progression on a prior CDK4/6i may still offer advantageous therapeutic effects.Cross-line CDK4/6i therapy is an area of active investigation in the ongoing pursuit to improve outcomes for patients with HR+/human epidermal growth factor receptor 2(HER2)–ABC.Methods:This retrospective study enrolled 82 patients with HR+/HER2–ABC who were treated with cross-line CDK4/6is(abemaciclib,palbociclib,ribociclib,and dalpiciclib)after progression with another CDK4/6i.The primary endpoint was progression-free survival(PFS)according to version 1.1 of the Response Evaluation Criteria in Solid Tumors.Secondary endpoints included toxicity,objective response rate,disease control rate,and overall survival.Adverse events(AEs)were graded according to version 5.0 of the Common Terminology Criteria for Adverse Events,as promulgated by the U.S.Department of Health and Human Services.Results:Eighty-two HR+/HER2–ABC patients who received cross-line CDK4/6i therapy from January 2022 to February 2024 were enrolled.The median age of the patients was 60 years.The median PFS of all patients was 7.6 months(95%CI,5.9-9.2).Cox regression analysis identified lung metastasis and a switch to endocrine therapy following prior CDK4/6i therapy as independent predictive factors for PFS.Notably,patients who previously received abemaciclib and switched to palbociclib upon disease progression had a median PFS of 10.7 months.The strategy of transitioning to chemotherapy after progression on a prior CDK4/6i,then to a subsequent CDK4/6i merits further investigation.Hematologic toxicity was the most common grade≥3 AEs.No instances of fatal safety events were observed.Conclusions:Cross-line CDK4/6i therapy is associated with significant clinical benefits and manageable safety profiles in patients with HR+/HER2–ABC,which underscores cross-line CDK4/6i therapy potential as an effective treatment strategy.

CDK4/6 inhibitors in the treatment of hormone receptor-positive, HER2-negative advanced breast cancer

Endocrine therapy(ET)is the therapy backbone of hormone receptor(HR)-positive and human epidermal growth factor receptor 2(HER2)-negati ve advanced breast cancer.However,there are about 20%HR positive patients with no response to ET due to primary or acquired ET resistance.In this background,many agents have been studied to overcome ET resistance and of which the important agents are cyclin-dependent kinase 4/6(CDK4/6)inhibitors.The prognosis of advanced breast cancer has been improved by combing ET with CDK4/6 inhibitors.In this review,we mainly focused on the CDK4/6 inhibitors in the treatment of HR-positive,HER2-negative advanced breast cancer and discussed the action mechanisms of CDK4/6 inhibitors alone or combined with ET.We also summarized several molecular features that would predict response or resistance to CDK4/6 inhibitors.In addition,we put forward possible strategies to overcome CDK4/6 inhibitor resistance according to the latest research.

Impact of Drug-Drug Interaction between CDK4/6 Inhibitors and Proton Pump Inhibitors on Survival Outcomes in the Treatment of Metastatic Breast Cancer—Real World Data from a Portuguese Center

Introduction: Proton pump inhibitors (PPi) are widely prescribed, including in patients undergoing treatment for advanced breast cancer (ABC). Due to the pharmacokinetic characteristics of the CDK4/6 inhibitor (Ci) palbociclib a drug interaction with PPi was hypothesized. It was shown in a retrospective study that this association was an independent predictive factor for worse progression-free survival (PFS). Objective: To verify the impact of concomitant administration of PPi with Ci on overall survival (OS) and PFS. Material and Methods: This is a retrospective cohort study of patients treated with Ci for HR+HER2-ABC in the period from Feb/2017 to Aug/2020. SPSS software was used for data processing. Univariate analysis was done by the Kaplan-Meier method and log-rank test, and multivariate analysis by COX regression. P-value < 0.05 was considered significant. Results: 80 patients were included. The median age at diagnosis of ABC was 56 years (25 - 75). Treatment with Ci was 1st line for ABC in 68.8%. Choice of Ci was palbociclib in 73.8% (n = 59) and ribociclib in 26.3% (n = 21). The hormone partner was a nonsteroidal aromatase inhibitor in 45.0%, and fulvestrant in 55.0% of cases. 37.5% of patients were on PPi, and 70.0% of them were during the entire treatment (23.3% omeprazole, 73.4% pantoprazole, 3.3% others). Patients taking concomitant PPi and Ci had lower OS (OS-3 years 42.6% vs. 63.4%, p = 0.254) and PFS (PFS med 15 m. vs. 21 m., p = 0.733), although with no statistically significant difference. Discussion: In the sample, there was a numerical difference, without the statistical significance in the use of PPi in the survival of patients under Ci. This difference could be more evident with a longer follow-up and a larger sample size. This study intends to alert to the growing importance of checking for drug interactions. Polymedication, advanced age and the presence of several comorbidities are real problems in patients with ABC. Conclusion: Real-world data from this center demonstrate a negative, non-statistically significant impact of PPi treatment on survival outcomes, in patients treated with Ci for HR+HER2-ABC.

Can cyclin-dependent kinase 4/6 inhibitors convert inoperable breast cancer relapse to operability? A case report

BACKGROUND Pathological complete response(pCR) is rare in hormone receptor-positive(HR+)HER2-negative breast cancer(BC) treated with either endocrine therapy(ET) or chemotherapy. Radical resection of locoregional relapse, although potentially curative in some cases, is challenging when the tumor invades critical structures.The oral cyclin-dependent kinase 4/6 inhibitor palbociclib in combination with ET has obtained a significant increase in objective response rates and progression-free survival in patients with advanced BC and is now being evaluated in the neoadjuvant setting. We present a clinical case of a patient with an inoperable locoregional relapse of HR+ HER2-negative BC who experienced p CR after treatment with palbociclib.CASE SUMMARY We report the clinical case of a 60-year-old patient who presented with an inoperable locoregional relapse of HR+, HER2-negative BC 10 years after the diagnosis of the primary tumor. During a routine follow-up visit, breast magnetic resonance imaging and positron emission tomography/computed tomography revealed a 4-cm lesion in the right subclavicular region, infiltrating the chest wall and extending to the subclavian vessels, but without bone or visceral involvement. Treatment was begun with palbociclib plus letrozole, converting the disease to operability over a period of 6 mo. Surgery was performed and a p CR achieved. Of note, during treatment the patient experienced a very uncommon toxicity characterized by burning tongue and glossodynia associated with dysgeusia, paresthesia, dysesthesia, and xerostomia. A reduction in the dose of palbociclib did not provide relief and treatment with the inhibitor was thus discontinued, resolving the tongue symptoms. Laboratory exams were unremarkable. Given that this was a late relapse, the tumor was classified asendocrine-sensitive, a condition associated with high sensitivity to palbociclib.CONCLUSION This case highlights the potential of the cyclin-dependent kinase 4/6 inhibitor plus ET combination to achieve pCR in locoregional relapse of BC, enabling surgical resection of a lesion initially considered inoperable.

A Systematic Review of Economic Evaluation of CDK4/6 Inhibitors in HR+/HER2-Advanced Breast Cancer

Objective To review the domestic and foreign economic studies on CDK4/6 inhibitors in first-line or second-line treatment of HR+/HER2-advanced breast cancer,and to analyze the main methodologies and research results.Methods Systematic literature review was used to search PubMed,EMBASE,Cochrane Library,CNKI,CBM,and Wanfang database.The incremental cost-effectiveness ratio was taken as the main outcome index,and all pharmacoeconomic evaluations with CDK4/6 inhibitors as intervention measures were included,such as Palbociclib,Ribociclib,and Abemaciclib.According to the Quality of Health Economic Studies Instrument,the quality of the included articles was evaluated,and then the included literature was analyzed.Results and Conclusion A total of 16 pharmacoeconomic evaluation studies were included,mainly from the perspective of national healthcare systems or third-party payers.Only 2 studies focused on second-line treatment,and the remaining treatment levels were first-line treatment.In terms of model structure,7 studies adopted the Markov model,6 studies adopted the PSM model,and 3 studies adopted the DES model.The basic analysis results showed that CDK4/6 inhibitor combined with endocrine regimen was not economical compared with endocrine alone regimen when the threshold was the conventional willingness to pay(WTP)value of each country.The uncertainty analysis included deterministic sensitivity analysis and probability sensitivity analysis.The included studies are all Cost-Utility Analysis with high-quality evaluation,which can provide evidence support for health-related decision-makers in decision-making.It can also provide methodological reference for the economic evaluation of other targeted drugs.

FSIP1 enhances the therapeutic sensitivity to CDK4/6 inhibitors in triple-negative breast cancer patients by activating the Nanog pathway

CDK4/6 inhibitors are routinely recommended agents for the treatment of advanced HR+HER2-breast cancer.However,their therapeutic effectiveness in triple-negative breast cancer(TNBC)remains controversial.Here,we observed that the expression level of fibrous sheath interacting protein 1(FSIP1)could predict the treatment response of TNBC to CDK4/6 inhibitors.High FSIP1 expression level was related to a poor prognosis in TNBC,which was associated with the ability of FSIP1 to promote tumor cell proliferation.FSIP1 downregulation led to slowed tumor growth and reduced lung metastasis in TNBC.FSIP1knockout caused cell cycle arrest at the G0/G1 phase and reduced treatment sensitivity to CDK4/6 inhibitors by inactivating the Nanog/CCND1/CDK4/6 pathway.FSIP1 could form a complex with Nanog,protecting it from ubiquitination and degradation,which may facilitate the rapid cell cycle transition from G0/G1 to S phase and exhibit enhanced sensitivity to CDK4/6 inhibitors.Our findings suggest that TNBC patients with high FSIP1 expression levels may be suitable candidates for CDK4/6 inhibitor treatment.

LA-D-B1,a novel Abemaciclib derivative,exerts anti-breast cancer effects through CDK4/6

Background:Regulatory proteins involved in human cellular division and proliferation,cyclin-dependent kinases 4 and 6(CDK4/6)are overexpressed in numerous cancers,including triple-negative breast cancer(TNBC).TNBC is a common pathological subtype of breast cancer that is prone to recurrence and metastasis,and has a single treatment method.As one of the CDK4/6 inhibitors,abemaciclib can effectively inhibit the growth of breast tumors.In this study,we synthesized LA-D-B1,a derivative of Abemaciclib,and investigated its anti-tumor effects in breast cancer.Methods:Cellular viability was assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide(MTT)assay.Cell cloning and migration abilities were determined by colony formation assay and wound healing assay.Cell invasion abilities and adhesion were determined by cell invasion assay and cell adhesion assay.The impact of compound LA-D-B1 on cell proliferation and the cell cycle was analyzed through Western blotting,which quantified the levels of proteins associated with the cyclin-dependent kinase(CDK)4/6-cyclin D-Rb-E2F pathway.The in vivo anti-tumor activity of compound LA-D-B1 was investigated using a chick chorioallantoic membrane(CAM)model.Results:The study demonstrated that LA-D-B1 effectively suppressed breast cancer cell proliferation,induced apoptosis,and caused cell cycle arrest.Furthermore,LA-D-B1 reduced the expression of key proteins in the CDK4/6-cyclin D-Rb-E2F pathway,including CDK4,CDK6 and E2F1.The results also indicated significant antitumor activity of LA-D-B1 in a transplanted tumor model.Conclusion:In this study,LA-D-B1 demonstrated a potent anti-tumor effect by effectively suppressing cell proliferation and inhibiting cell cycle progression in breast cancer.These findings highlight the potential of LA-D-B1 as a valuable compound for enhancing therapeutic outcomes and controlling the progression of breast cancer.

Endocrine therapy in metastatic breast cancer-more than just CDK4/6 inhibitors

Advanced hormone receptor-positive breast cancer is one of the women’s most common malignant diseases and remains incurable despite recent therapeutic innovations.The dependence of hormone receptor-positive breast cancer on hormonal growth signals offers the possibility of inhibiting this signaling pathway using anti-hormonal therapy.Nevertheless,the development of resistance to antitumoral drugs remains a challenge.Molecularly-targeted substances significantly improve survival rates and(as in the case of cyclin-dependent kinase 4 and 6 inhibitors)are widely used in clinical practice and enhance endocrine therapy’s efficacy.Agents such as everolimus,alpelisib,and capivasertib target the phosphoinositide 3 kinase/protein kinase B/mammalian target of rapamycin pathway,which is a promising approach to overcoming endocrine resistance.Novel therapies are being studied in numerous trials,and some already show significant benefits in survival rates.The development of new therapies to avert endocrine resistance is an urgent challenge in modern medicine.The following review will examine some promising therapeutic approaches.

Overexpressed Cyclin D1 and CDK4 proteins are responsible for the resistance to CDK4/6 inhibitor in breast cancer that can be reversed by PI3K/mTOR inhibitors

CDK4/6 inhibitors are the standard treatment in advanced HR+/HER2-breast cancer patients.Nevertheless,the resistance to CDK4/6 inhibitors is inevitable and the strategies to overcome resistance are of great interest.Here,we show that the palbociclibresistant breast cancer cells expressed significantly higher levels of Cyclin D1 and CDK4 proteins because of upregulated protein synthesis.Silencing Cyclin D1 or CDK4 led to cell cycle arrest while silencing Cyclin E1 or CDK2 restored the sensitivity to palbociclib.Furthermore,PI3K/mTOR pathway was hyper-activated in palbociclib-resistant cells,leading to more phosphorylated 4E-BP1 and higher levels of Cyclin D1 and CDK4 translation.Targeting PI3K/mTOR pathway with a specific PI3Kαinhibitor(BYL719)or an mTOR inhibitor(everolimus)reduced the protein levels of Cyclin D1 and CDK4,and restored the sensitivity to palbociclib.The tumor samples expressed significantly higher levels of Cyclin D1,CDK4,p-AKT and p-4E-BP1 after progression on palbociclib treatment.In conclusion,our findings suggest that overexpressed Cyclin D1 and CDK4 proteins lead to the resistance to CDK4/6 inhibitor and PI3K/mTOR inhibitors are able to restore the sensitivity to CDK4/6 inhibitors,which provides the biomarker and rationale for the combinational use of CDK4/6 inhibitors and PI3K/mTOR inhibitors after CDK4/6 inhibitor resistance in breast cancer.

Expression dynamics of periodic transcripts during cancer cell cycle progression and their correlation with anticancer drug sensitivity

Background:The cell cycle is at the center of cellular activities and is orchestrated by complex regulatory mechanisms,among which transcriptional regulation is one of the most important components.Alternative splicing dramatically expands the regulatory network by producing transcript isoforms of genes to exquisitely control the cell cycle.However,the patterns of transcript isoform expression in the cell cycle are unclear.Therapies targeting cell cycle checkpoints are commonly used as anticancer therapies,but none of them have been designed or evaluated at the alternative splicing transcript level.The utility of these transcripts as markers of cell cycle-related drug sensitivity is still unknown,and studies on the expression patterns of cell cycle-targeting drug-related transcripts are also rare.Methods:To explore alternative splicing patterns during cell cycle progression,we performed sequential transcriptomic assays following cell cycle synchronization in colon cancer HCT116 and breast cancer MDA-MB-231 cell lines,using flow cytometry and reference cell cycle transcripts to confirm the cell cycle phases of samples,and we developed a new algorithm to describe the periodic patterns of transcripts fluctuating during the cell cycle.Genomics of Drug Sensitivity in Cancer(GDSC)drug sensitivity datasets and Cancer Cell Line Encyclopedia(CCLE)transcript datasets were used to assess the correlation of genes and their transcript isoforms with drug sensitivity.We identified transcripts associated with typical drugs targeting cell cycle by determining correlation coefficients.Cytotoxicity assays were used to confirm the effect of ENST00000257904 against cyclin dependent kinase 4/6(CDK4/6)inhibitors.Finally,alternative splicing transcripts associated with mitotic(M)phase arrest were analyzed using an RNA synthesis inhibition assay and transcriptome analysis.Results:We established high-resolution transcriptome datasets of synchronized cell cycle samples from colon cancer HCT116 and breast cancer MDA-MB-231 cells.The results of the cell cycle assessment showed that 43,326,41,578 and 29,244 transcripts were found to be periodically expressed in HeLa,HCT116 and MDA-MB-231 cells,respectively,among which 1280 transcripts showed this expression pattern in all three cancer cell lines.Drug sensitivity assessments showed that a large number of these transcripts displayed a higher correlation with drug sensitivity than their corresponding genes.Cell cycle-related drug screening showed that the level of the CDK4 transcript ENST00000547281 was more significantly associated with the resistance of cells to CDK4/6 inhibitors than the level of the CDK4 reference transcript ENST00000257904.The transcriptional inhibition assay following M phase arrest further confirmed the M-phase-specific expression of the splicing transcripts.Combined with the cell cycle-related drug screening,the results also showed that a set of periodic transcripts,for example,ENST00000314392(a dolichylphosphate mannosyltransferase polypeptide 2 isoform transcript),was more associated with drug sensitivity than the levels of their corresponding gene transcripts.Conclusions:In summary,we identified a panel of cell cycle-related periodic transcripts and found that the levels of transcripts of drug target genes showed different values for predicting drug sensitivity,providing novel insights into alternative splicing-related drug development and evaluation.

Cell cycle regulation and anticancer drug discovery

Cellular growth,development,and differentiation are tightly controlled by a conserved biological mechanism:the cell cycle.This cycle is primarily regulated by cyclin-dependent kinase(CDK)-cyclin complexes,checkpoint kinases,and CDK inhibitors.Deregulation of the cell cycle is a hallmark of the transformation of normal cells into tumor cells.Given its importance in tumorigenesis,several cell cycle inhibitors have emerged as potential therapeutic drugs for the treatment of cancers-both as singleagent therapy and in combination with traditional cytotoxic or molecular targeting agents.In this review,we discuss the mechanisms underlying cell cycle regulation and present small-molecule anticancer drugs that are under development,including both pan-CDK inhibitors and CDK4/6-selective inhibitors.In addition,we provide an outline of some promising CDK inhibitors currently in preclinical and clinical trials that target cell cycle abnormalities in various cancers.

Discovery of 4-Thiazol-N-(pyridin-2-yl)pyrimidin-2-amine as Novel Cyclin-dependent Kinases 4 and 6 Dual Inhibitors via 3D-QSAR and Molecular Simulation

Cyclin D dependent kinases 4/6 regulate the entry of cells into S phase and are effective target for the discovery of anticancer drugs.In this article,3D-QSAR modeling including comparative molecular field analy-sis(CoMFA)and comparative molecular similarity indices analysis fields(CoMSIA)was implemented on 52 dual CDK4/6 inhibitors.As a result,we obtained a pretty good 3D-QSAR model,which is CoMFACDK4 with q2 to be 0.543 and r^(2) to be 0.967;CoMSIACDK4 with q2 being 0.518 and r^(2) being 0.937;CoMFACDK6 with q2 to be 0.624 and r^(2) to be 0.984;CoMSIACDK6 with q2 being 0.584 and r^(2) being 0.975.Molecular docking confirmed the important residues for interactions.Molecular dynamics simulation further confirmed binding affinity with key residues of protein,such as Lys22,Lys35,Val96 for CDK4 and Lys43,His100,Val101 for CDK6 at the active sites.Then these results offered new directions to explore new inhibitors of CDK4/6.Finally,we designed 10 novel compounds with promising expected activity and ADME/T properties,and provided referable synthetic routes.

水稻黑条矮缩病毒S6片段的序列多样性与进化分析

0 引言植物RNA病毒在进化中具有快速变异的能力,有利于病毒扩大寄主范围甚至进化为新病毒[1]。突变和重组是植物RNA病毒变异和遗传多样性的共同进化因素,是群体基因变异的最初来源[2]。由灰飞虱传播的水稻黑条矮缩病毒(Rice black streaked dwarf virus, RBSDV) 属于呼肠孤病毒科(Reoviridae)斐济病毒属(Fijivirus),能引发玉米粗缩病和水稻黑条矮缩病。

Liquid biopsies to predict CDK4/6 inhibitor efficacy and resistance in breast cancer

Cyclin-dependent kinase 4 and 6(CDK4/6)inhibitors combined with endocrine therapy have transformed the treatment of estrogen receptor-positive(ER+)and human epidermal growth factor receptor 2 negative(HER2-)metastatic breast cancer.However,some patients do not respond to this treatment,and patients inevitably develop resistance,such that novel biomarkers are needed to predict primary resistance,monitor treatment response for acquired resistance,and personalize treatment strategies.Circumventing the spatial and temporal limitations of tissue biopsy,newly developed liquid biopsy approaches have the potential to uncover biomarkers that can predict CDK4/6 inhibitor efficacy and resistance in breast cancer patients through a simple blood test.Studies on circulating tumor DNA(ctDNA)-based liquid biopsy biomarkers of CDK4/6 inhibitor resistance have focused primarily on genomic alterations and have failed thus far to identify clear and clinically validated predictive biomarkers,but emerging epigenetic ctDNA methodologies hold promise for further discovery.The present review outlines recent advances and future directions in ctDNA-based biomarkers of CDK4/6 inhibitor treatment response.

Acid-activatible micelleplex delivering siRNA-PD-L1 for improved cancer immunotherapy of CDK4/6 inhibition

Cyclin-dependent kinases 4 and 6 inhibitors(CDK4/6i)have been demonstrated to trigger antitumor immunity for tumor regression.However,the therapeutic performance of CDK4/6i-meadiated cancer immunotherapy was impaired by the immunosuppressive tumor microenvironment(ITM)due to overexpression of programmed death ligand 1(PD-L1)on the surface of cancer cell membrane.To improve the immunotherapeutic performance of CDK4/6i,we herein developed endosomal acidactivatable micelleplex for si RNA delivery and PD-L1 knockdown in the tumor cells in vitro and in vivo.We further demonstrated that the combination of PD-L1 knockdown and CDK4/6 inhibition facilitated intratumoral infiltration of cytotoxic T lymphocytes(CTLs),and elicited protective immune response and efficiently suppressed tumor growth in vivo.This study revealed the importance of molecular design of the micelleplex for highly efficient si RNA delivery,which might provide a novel insight for RNAi-based cancer immunotherapy.

circBIRC6 contributes to the development of non-small cell lung cancer via regulating microRNA-217/amyloid beta precursor protein binding protein 2 axis

Background:Circular RNAs(circRNAs)are considered to be important regulators in cancer biology.In this study,we focused on the effect of circRNA baculoviral inhibitor of apoptosis protein(IAP)repeat containing 6(circBIRC6)on non-small cell lung cancer(NSCLC)progression.Methods:The NSCLC and adjacent non-tumor tissues were collected at Shanghai Ninth People's Hospital.Quantitative real-time polymerase chain reaction was conducted for assessing the levels of circBIRC6,amyloid beta precursor protein binding protein 2(APPBP2)messenger RNA(mRNA),baculoviral IAP repeat containing 6 mRNA(BIRC6),and microRNA-217(miR-217).Western blot assay was adopted for measuring the protein levels of APPBP2,E-cadherin,N-cadherin,and vimentin.Colony formation assay,transwell assay,and flow cytometry analysis were utilized for evaluating cell colony formation,metastasis,and apoptosis.Dualluciferase reporter assay and RNA immunoprecipitation assay were carried out to determine the interaction between miR-217 and circBIRC6 and APPBP2 in NSCLC tissues.The murine xenograft model assay was used to investigate the function of circBIRC6 in tumor formation in vivo.Differences were analyzed via Student's t test or one-way analysis of variance.Pearson's correlation coefficient analysis was used to analyze linear correlation.Results:CircBIRC6 was overexpressed in NSCLC tissues and cells.Knockdown of circBIRC6 repressed the colony formation and metastasis and facilitated apoptosis of NSCLC cells in vitro and restrained tumorigenesis in vivo.Mechanically,circBIRC6 functioned as miR-217 sponge to promote APPBP2 expression in NSCLC cells.MiR-217 inhibition rescued circBIRC6 knockdown-mediated effects on NSCLC cell colony formation,metastasis,and apoptosis.Overexpression of miR-217 inhibited the malignant phenotypes of NSCLC cells,while the effects were abrogated by elevating APPBP2.Conclusion:CircBIRC6 aggravated NSCLC cell progression by elevating APPBP2 via sponging miR-217,which might provide a fresh perspective on NSCLC therapy.

Design, Synthesis and Biological Evaluation of Novel Selective Thiol-based Histone Deacetylase（HDAC） Ⅵ Inhibitors Bearing Indeno[1,2-c]pyrazole or Benzoindazole Scaffold

A series of thiol-based mdeno[1,2-c]pyrazoles and benzoindazole compounds was designed and synthesized according to the structural specificity of his-tone deacetylase VI（HDAC6） and the structural characteristics of HDAC inhibitors. The inhibitory activities of the target compounds against HDAC6 and HDAC1 were screened by fluorescence analysis. Most of the target compounds showed moderate inhibitory activity against HDAC6（IC50=44-598 nmol/L）. Among them, compound A-4 displayed the highest selectivity against HDAC6 and similar inhibitory activity（IC50=44 nmol/L） to that of the positive drug SAHA（IC50=41 nmol/L） against HDAC6.

Beyond clinical trials:CDK4/6 inhibitor efficacy predictors and nomogram model from real‐world evidence in metastatic breast cancer

Background:CDK4/6 inhibitors(CDK4/6i)have shown promising results in the treatment of hormone receptor‐positive(HR+)metastatic breast cancer(MBC)when combined with endocrine therapy(ET).It is crucial to evaluate the actual effectiveness and safety of CDK4/6i in clinical practice,as well as to analyze the factors that can predict their outcomes.Methods:Patients with HR+MBC who received CDK4/6i‐based therapy between May 2016 and May 2023 at Hunan Cancer Hospital were evaluated for progression‐free survival(PFS).Adverse reactions were assessed based on the National Cancer Institute Common Toxicity Criteria(version 5.0).Results:This study included 344 patients,with a median PFS(mPFS)of 12.8 months(range:10.4–15.2 months).After adjustment,Cox multivariate regression analysis revealed that visceral metastasis(specifically liver and brain metastases),Eastern Cooperative Oncology Group Performance Status(ECOG PS)≥1,estrogen receptor≤80%,progesterone receptor≤10%,Ki‐67>30%,and treatment in later stages were significant factors associated with reduced PFS.Based on this,we created a prognostic nomogram and validated its performance,obtaining a C‐index of 0.714(95%confidence interval:0.640–0.787)as well as reliable calibration and clinical impact.The mPFS of CDK4/6i rechallenge was 7.7 months;for patients who initially discontinued CDK4/6i for reasons other than disease progression,CDK4/6i rechallenge still provided a mPFS of 11.4 months.The tolerability and safety of combining CDK4/6is with ET were manageable.Adverse events led to treatment discontinuation in 3.8%of patients.Neutropenia(29.1%),leukopenia(13.7%),and anemia(4.1%)were the primary grade 3/4 adverse reactions.Conclusions:This real‐world study highlights the ample efficacy and reasonable safety of combined CDK4/6i and ET in patients with HR+MBC.Individualized treatment decisions and ongoing safety monitoring are important to optimize the therapeutic benefit of CDK4/6i treatment.

Targeted lapatinib anti-HER2/ErbB2 therapy resistance in breast cancer:opportunities to overcome a difficult problem

Approximately 20%of invasive breast cancers have upregulation/gene amplification of the oncogene human epidermal growth factor receptor-2(HER2/ErbB2).Of these,some also express steroid receptors(the so-called Luminal B subtype),whereas others do not(the HER2 subtype).HER2 abnormal breast cancers are associated with a worse prognosis,chemotherapy resistance,and sensitivity to selected anti-HER2 targeted therapeutics.Transcriptional data from over 3000 invasive breast cancers suggest that this approach is overly simplistic;rather,the upregulation of HER2 expression resulting from gene amplification is a driver event that causes major transcriptional changes involving numerous genes and pathways in breast cancer cells.Most notably,this includes a shift from estrogenic dependence to regulatory controls driven by other nuclear receptors,particularly the androgen receptor.We discuss members of the HER receptor tyrosine kinase family,heterodimer formation,and downstream signaling,with a focus on HER2 associated pathology in breast carcinogenesis.The development and application of anti-HER2 drugs,including selected clinical trials,are discussed.In light of the many excellent reviews in the clinical literature,our emphasis is on recently developed and successful strategies to overcome targeted therapy resistance.These include combining anti-HER2 agents with programmed cell death-1 ligand or cyclin-dependent kinase 4/6 inhibitors,targeting crosstalk between HER2 and other nuclear receptors,lipid/cholesterol synthesis to inhibit receptor tyrosine kinase activation,and metformin,a broadly inhibitory drug.We seek to facilitate a better understanding of new approaches to overcome anti-HER2 drug resistance and encourage exploration of two other therapeutic interventions that may be clinically useful for HER+invasive breast cancer patients.