Targeting Mutated p53 Dependency in Triple-Negative Breast Cancer Cells Through CDK7 Inhibition

TP53 Mutation-Specific Dysregulation of Store-Operated Calcium Entry and Apoptotic Sensitivity in Triple-Negative Breast Cancer

Background: Triple-negative breast cancer (TNBC) is an aggressive subtype lacking estrogen, progesterone, and HER2 receptors, and is associated with poor prognosis and limited targeted therapeutic options. TP53 mutations occur in the majority of TNBC cases, disrupting p53's role in DNA repair and apoptosis. Beyond gene regulation, p53 also influences calcium signalling through store-operated calcium entry (SOCE), a critical pathway for cell survival and death. However, the impact of different TP53 mutation types on calcium signalling remains unclear. Methods: Calcium channel gene expression was analysed using publicly available TNBC datasets. Calcium channel expression and SOCE activity were assessed in TNBC cell lines with different TP53 mutations using quantitative PCR and calcium imaging (Fura-2AM). Cell proliferation was measured using acid phosphatase assays, while apoptosis was evaluated through caspase 3/7 activation using the Incucyte live-cell fluorescent imager. The p53 reactivator COTI-2 was tested for its ability to restore TP53 function and modulate calcium signalling. Results: Analysis revealed significant downregulation of CACNA1D in TP53-mutant TNBCs. TNBC cell lines harbouring frameshift and stop TP53 mutations exhibited reduced SOCE, lower CACNA1D expression, and resistance to thapsigargin-induced apoptosis compared to wild-type cells. In contrast, cells with the TP53 R273H missense mutation demonstrated similar calcium signalling and proliferation to TP53 wild-type cels. COTI-2 treatment restored CACNA1D expression and SOCE in frameshift and stop mutant cells, enhancing apoptotic sensitivity. Combined treatment with COTI-2 and thapsigargin resulted in a synergistic increase in apoptosis. Conclusions: This study identifies a novel link between TP53 mutation type and calcium signalling in TNBC. Reactivating mutant p53 with COTI-2 restores calcium-mediated apoptosis, supporting combination strategies targeting both TP53 dysfunction and calcium signalling.

Mechanistic Roles of Transcriptional Cyclin-Dependent Kinases in Oncogenesis: Implications for Cancer Therapy

Cyclin-dependent kinases (CDKs) are pivotal in regulating cell cycle progression and transcription, making them crucial targets in cancer research. The two types of CDKs that regulate different biological activities are transcription-associated CDKs (e.g., CDK7, 8, 9, 12, and 13) and cell cycle-associated CDKs (e.g., CDK1, 2, 4, and 6). One characteristic of cancer is the dysregulation of CDK activity, which results in unchecked cell division and tumor expansion. Targeting transcriptional CDKs, which control RNA polymerase II activity and gene expression essential for cancer cell survival, has shown promise as a therapeutic approach in recent research. While research into selective inhibitors for transcriptional CDKs is ongoing, inhibitors that target CDK4/6, such as palbociclib and ribociclib, have demonstrated encouraging outcomes in treating breast cancer. CDK7, CDK8, and CDK9 are desirable targets for therapy since they have shown oncogenic roles in a variety of cancer types, such as colorectal, ovarian, and breast malignancies. Even with significant advancements, creating selective inhibitors with negligible off-target effects is still difficult. This review highlights the need for more research to optimize therapeutic strategies and improve patient outcomes by giving a thorough overview of the non-transcriptional roles of CDKs in cancer biology, their therapeutic potential, and the difficulties in targeting these kinases for cancer treatment.

Biomarkers and potential function analysis of triple-negative breast cancer screening based on bioinformatics

This study aims to identify and validate potential endogenous biomarkers for triple-negative breast cancer (TNBC). TNBC microarray data (GSE38959, GSE53752) were retrieved from the Gene Expression Omnibus (GEO) database, and principal component analysis (PCA) was performed to evaluate the reliability of the data. The microarray datasets were merged, and differentially expressed genes (DEGs) were identified using R software. Functional enrichment analysis of the DEGs was conducted using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways. The most disease-relevant module was identified through Weighted Gene Co-expression Network Analysis (WGCNA), and genes within this module were intersected with the DEGs. The intersecting genes underwent Least Absolute Shrinkage and Selection Operator (LASSO) regression analysis to minimize errors and identify TNBC-specific genes. Sensitivity and survival analyses were performed on the identified specific genes. There were 10 TNBC-specific genes identified: RRM2, DEPDC1, FIGF, TACC3, E2F1, CDO1, DST, MCM4, CHEK1, and PLSCR4. RT-qPCR analysis showed significant upregulation of CDO1, MCM4, DEPDC1, RRM2, and E2F1 in MDA-MB-231, CAL-148, and MFM-223 compared to MCF-10A. Our findings provide new insights into TNBC pathogenesis and potential therapeutic strategies, with important clinical implications for further understanding TNBC mechanisms and developing innovative treatments.

Autocrine Motility Factor and Its Peptide Derivative Inhibit Triple-Negative Breast Cancer by Regulating Wound Repair, Survival, and Drug Efflux

Triple-negative breast cancer (TNBC) presents a significant challenge in oncology due to its aggressive nature and limited targeted therapeutic options. This study explores the potential of autocrine motility factor (AMF) and an AMF-derived peptide as novel treatments for TNBC. AMF, primarily secreted by neoplastic cells, plays a crucial role in cancer cell motility, metastasis, and proliferation. The research demonstrates that AMF and its derived peptide inhibit TNBC cell proliferation by modulating cellular migration, redox homeostasis, apoptotic pathways, and drug efflux mechanisms. Dose-dependent antiproliferative effects were observed across three TNBC cell lines, with higher concentrations impairing cellular migration. Mechanistic studies revealed decreased glucose-6-phosphate dehydrogenase expression and elevated reactive oxygen species production, suggesting redox imbalance as a primary mediator of apoptosis. Combination studies with conventional therapeutics showed near-complete eradication of resistant TNBC cells. The observed reduction in p53 levels and increased intranuclear doxorubicin accumulation highlight the AMF/AMF peptide's potential as multidrug resistance modulators. This study underscores the promise of using AMF/AMF peptide as a novel therapeutic approach for TNBC, addressing current treatment limitations and warranting further investigation.

Global trends and topics in CDK7 inhibitor research: a bibliometric analysis

Background

CDK7 has been demonstrated to play a crucial role in the initiation and progression of malignancy. Therefore, targeting CDK7, which regulates the transcription process, has emerged as a new promising approach for treating cancer. Research on CDK7 inhibitors has significantly increased over the past 2 decades, with almost 600 related papers in the Web of Science Core Collection database. To effectively identify future research hotspots and potential future directions, it is crucial to systematically review and visually present the research on this topic from a comprehensive viewpoint, ensuring scientific reliability.

Methods

This study performed bibliometric analysis via CiteSpace and VOSviewer scientometrics analysis software to examine data on the publication of articles on CDK7 inhibitors over the past 2 decades; the data included country of publication, author names, institution names, scientific categories, cited journals, and keywords related to the field of CDK7 inhibitors.

Results

This bibliometric analysis included 426 publications from 41 different nations, referencing a total of 15,892 sources. Research associated with CDK7 inhibitors has rapidly expanded since 2016, and the US and China are the two countries with the highest publication output among the countries and institutes that produce literature on CDK7 inhibitors. Furthermore, the US is the country that most frequently engages in international cooperation. The evolution of keywords identifying antitumor strategies related to CDK7-mediated cellular transcription processes has been the research focus in recent years.

Conclusion

In this study, we identified research efforts and their evolving patterns and predicted advances in the CDK7 inhibitor field. The knowledge structure of CDK7 inhibitors encompasses pharmacological mechanisms, therapeutic targets, and cancer treatment strategies. The primary objectives of contemporary research are to discover the processes underlying cancer progression, identify specific signaling pathways, and develop effective clinical medicines.

Ferroptosis as a promising targeted therapy for triple negative breast cancer

PURPOSE

Triple negative breast cancer (TNBC) is a challenging subtype characterized by the absence of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) expression. Standard treatment options are limited, and approximately 45% of patients develop distant metastasis. Ferroptosis, a regulated form of cell death triggered by iron-dependent lipid peroxidation and oxidative stress, has emerged as a potential targeted therapy for TNBC.

METHODS

This study utilizes a multifaceted approach to investigate the induction of ferroptosis as a therapeutic strategy for TNBC. It explores metabolic alterations, redox imbalance, and oncogenic signaling pathways to understand their roles in inducing ferroptosis, characterized by lipid peroxidation, reactive oxygen species (ROS) generation, and altered cellular morphology. Critical pathways such as Xc-/GSH/GPX4, ACSL4/LPCAT3, and nuclear factor erythroid 2-related factor 2 (NRF2) are examined for their regulatory roles in ferroptosis and their potential dysregulation contributing to cancer cell survival and resistance.

RESULTS

Inducing ferroptosis has been shown to inhibit tumor growth, enhance the efficacy of conventional therapies, and overcome drug resistance in TNBC. Lipophilic antioxidants, GPX4 inhibitors, and inhibitors of the Xc- system have been demonstrated to be potential ferroptosis inducers. Additionally, targeting the NRF2 pathway and exploring other ferroptosis regulators, such as ferroptosis suppressor protein 1 (FSP1), and the PERK-eIF2α-ATF4-CHOP pathway, may offer novel therapeutic avenues.

CONCLUSION

Further research is needed to understand the mechanisms, optimize therapeutic strategies, and evaluate the safety and efficacy of ferroptosis-targeted therapies in TNBC treatment. Overall, targeting ferroptosis represents a promising approach to improving treatment outcomes and overcoming the challenges posed by TNBC.

Pharmacoinformatics approach for the screening of Kovidra (Bauhinia variegata) phytoconstituents against tumor suppressor protein in triple negative breast cancer

Globally, 2.3 million women were diagnosed with breast cancer, with 6,85000 mortalities in year 2021; making it the world's most prevalent cancer. This growing global burden necessitates a new treatment option, and plant-based medicines offers a promising alternative to conventional cancer treatment. In this work, screening of phytoconstituents of an indigenous therapeutic plant, Bauhinia variegata carried out for potential regulator of tumor suppressor protein p53. Here, an in-silico analysis was employed to develop more effective, pharmaceutically potent small drug-like compounds that target tumor suppressor protein p53. The methanol and aqueous powdered extracts of Bauhinia variegata were prepared and phytochemically evaluated along with antioxidant property evaluation. The LC50 of methanol (325.33 µg/ml) and aqueous extract (361.15 µg/ml) showed their cytotoxic characteristics. Further, GCMS analysis of both the extracts reveals total 57 secondary metabolites. Among these, four lead compounds; compound 1, compound 2, compound 3 and compound 4 were found to have the highest binding ability (-8.15 to -5.40 kcal/mol) with p53. MD simulation and binding free energy validates these findings with highest binding free energy (-67.09 ± 4.87 kcal/mol) towards p53 by the lead phytocompound 2. Selected compounds exhibit excellent pharmacokinetic features and drug-like characteristics. The acute toxicity (LD50) values of the lead phytocompounds ranges from 670 mg/kg to 3100 mg/kg, with toxicity classes of IV and V. As a result, these druggable phytochemicals could serve as potential lead applicants for triple negative breast cancer treatment. However, more in vitro and in vivo research is planned to produce future breast cancer medicine. HIGHLIGHTSScreening of phytoconstituents of an indigenous therapeutic plant, Bauhinia variegata, for potential regulator of tumor suppressor protein p53.The LC50 of methanol (325.33µg/ml) and aqueous extract (361.15µg/ml) showed their cytotoxic characteristics.GCMS analysis of both the extracts reveals total 57 secondary metabolites. Among these, four lead compounds were found to have the highest binding affinity (-8.153 to -5.401 kcal/mol) with tumor suppressor protein p53.MD simulation along with the Prime MM/GBSA binding free energy validates this discovery with highest binding free energy (-67.09 ± 4.87 kcal/mol) towards p53 by the lead compound 2.The acute toxicity (LD50) values of the lead phytocompounds ranges from 670 mg/kg to 3100 mg/kg, with toxicity classes of IV and V.As a result, these druggable phytochemicals could serve as potential lead applicants for triple negative breast cancer treatment.Communicated by Ramaswamy H. Sarma.

Cyclin-dependent kinase inhibitors enhance programmed cell death protein 1 immune checkpoint blockade efficacy in triple-negative breast cancer by affecting the immune microenvironment

BACKGROUND

Clinical studies on programmed death-ligand 1 (PD-L1) immune checkpoint inhibitors for treating triple-negative breast cancer (TNBC) have shown unsatisfactory efficacy due to low tumor-infiltrating lymphocyte (TIL) levels. Inhibitors targeting cyclin-dependent kinase (CDK) proteins can affect the immune microenvironment, increase TIL levels, and promote antitumor immunity, thus providing a new direction for TNBC treatment strategies.

METHODS

The authors tested three CDK inhibitors on the TNBC cell lines MDA-MB-231 and 4T1 and validated their antitumor effects and impact on the immune microenvironment using multiple detection methods. They verified the efficacy and immune-related mechanisms of different combination therapy experiments in a 4T1 cell-transplanted BALB/c mouse model.

RESULTS

Treatment with CDK inhibitors for 72 hours inhibited cell proliferation, clone formation, migration, and cell-cycle arrest and induced apoptosis in human breast cancer MDA-MB-231 cells and mouse breast cancer 4T1 cells. CDK inhibitors suppressed DNA methylation by downregulating DNMT1, DNMT3a, and DNMT3b expression. These three inhibitors promoted the secretion of various chemokines, enhanced tumor cell antigen presentation, and increased PD-L1 expression. CDK inhibitors improved the efficacy of immunotherapy in animal models and increased TIL levels.

CONCLUSIONS

Combination therapy with CDK and PD-L1 immune checkpoint inhibitors affects the immune microenvironment, promotes antitumor immunity, and improves the efficacy of immunotherapy for TNBC.

CDK7 in breast cancer: mechanisms of action and therapeutic potential

Cyclin-dependent kinase 7 (CDK7) serves as a pivotal regulator in orchestrating cellular cycle dynamics and gene transcriptional activity. Elevated expression levels of CDK7 have been ubiquitously documented across a spectrum of malignancies and have been concomitantly correlated with adverse clinical outcomes. This review delineates the biological roles of CDK7 and explicates the molecular pathways through which CDK7 exacerbates the oncogenic progression of breast cancer. Furthermore, we synthesize the extant literature to provide a comprehensive overview of the advancement of CDK7-specific small-molecule inhibitors, encapsulating both preclinical and clinical findings in breast cancer contexts. The accumulated evidence substantiates the conceptualization of CDK7 as a propitious therapeutic target in breast cancer management.

An Antiherpesviral Host-Directed Strategy Based on CDK7 Covalently Binding Drugs: Target-Selective, Picomolar-Dose, Cross-Virus Reactivity

The repertoire of currently available antiviral drugs spans therapeutic applications against a number of important human pathogens distributed worldwide. These include cases of the pandemic severe acute respiratory coronavirus type 2 (SARS-CoV-2 or COVID-19), human immunodeficiency virus type 1 (HIV-1 or AIDS), and the pregnancy- and posttransplant-relevant human cytomegalovirus (HCMV). In almost all cases, approved therapies are based on direct-acting antivirals (DAAs), but their benefit, particularly in long-term applications, is often limited by the induction of viral drug resistance or side effects. These issues might be addressed by the additional use of host-directed antivirals (HDAs). As a strong input from long-term experiences with cancer therapies, host protein kinases may serve as HDA targets of mechanistically new antiviral drugs. The study demonstrates such a novel antiviral strategy by targeting the major virus-supportive host kinase CDK7. Importantly, this strategy focuses on highly selective, 3D structure-derived CDK7 inhibitors carrying a warhead moiety that mediates covalent target binding. In summary, the main experimental findings of this study are as follows: (1) the in vitro verification of CDK7 inhibition and selectivity that confirms the warhead covalent-binding principle (by CDK-specific kinase assays), (2) the highly pronounced antiviral efficacies of the hit compounds (in cultured cell-based infection models) with half-maximal effective concentrations that reach down to picomolar levels, (3) a particularly strong potency of compounds against strains and reporter-expressing recombinants of HCMV (using infection assays in primary human fibroblasts), (4) additional activity against further herpesviruses such as animal CMVs and VZV, (5) unique mechanistic properties that include an immediate block of HCMV replication directed early (determined by Western blot detection of viral marker proteins), (6) a substantial drug synergism in combination with MBV (measured by a Loewe additivity fixed-dose assay), and (7) a strong sensitivity of clinically relevant HCMV mutants carrying MBV or ganciclovir resistance markers. Combined, the data highlight the huge developmental potential of this host-directed antiviral targeting concept utilizing covalently binding CDK7 inhibitors.

Mechanistic Aspects of Biphenyl Urea-Based Analogues in Triple-Negative Breast Cancer Cell Lines

Triple-negative breast cancer (TNBC) poses significant challenges due to its aggressive nature and limited treatment options. In this study, we investigated the impact of urea-based compounds on TNBC cells to uncover their mechanisms of action and therapeutic potential. Notably, polypharmacology urea analogues were found to work via p53-related pathways, and their cytotoxic effects were amplified by the modulation of oxidative phosphorylation pathways in the mitochondria of cancer cells. Specifically, compound 1 demonstrated an uncoupling effect on adenosine triphosphate (ATP) synthesis, leading to a time- and concentration-dependent shift toward glycolysis-based ATP production in MDA-MB-231 cells. At the same time, no significant changes in ATP synthesis were observed in noncancerous MCF10A cells. Moreover, the unique combination of mitochondrial- and p53-related effects leads to a higher cytotoxicity of urea analogues in cancer cells. Notably, the majority of tested clinical agents, but sorafenib, showed significantly higher toxicity in MCF10A cells. To test our hypothesis of sensitizing cancer cells to the treatment via modulation of mitochondrial health, we explored the combinatorial effects of urea-based analogues with established chemotherapeutic agents commonly used in TNBC treatment. Synergistic effects were evident in most tested combinations in TNBC cell lines, while noncancerous MCF10A cells exhibited higher resistance to these combination treatments. The combination of compound 1 with SN38 displayed nearly 60-fold selectivity toward TNBC cells over MCF10A cells. Encouragingly, combinations involving compound 1 restored the sensitivity of TNBC cells to cisplatin. In conclusion, our study provides valuable insights into the mechanisms of action of urea-based compounds in TNBC cells. The observed induction of mitochondrial membrane depolarization, inhibition of superoxide dismutase activity, disruption of ATP synthesis, and cell-line-specific responses contribute to their cytotoxic effects. Additionally, we demonstrated the synergistic potential of compound 1 to enhance the efficacy of existing TNBC treatments. However, the therapeutic potential and underlying molecular mechanisms of urea-based analogues in TNBC cell lines require further exploration.

Endorsement of TNBC Biomarkers in Precision Therapy by Nanotechnology

Breast cancer is a heterogeneous disease which accounts globally for approximately 1 million new cases annually, wherein more than 200,000 of these cases turn out to be cases of triple-negative breast cancer (TNBC). TNBC is an aggressive and rare breast cancer subtype that accounts for 10-15% of all breast cancer cases. Chemotherapy remains the only therapy regimen against TNBC. However, the emergence of innate or acquired chemoresistance has hindered the chemotherapy used to treat TNBC. The data obtained from molecular technologies have recognized TNBC with various gene profiling and mutation settings that have helped establish and develop targeted therapies. New therapeutic strategies based on the targeted delivery of therapeutics have relied on the application of biomarkers derived from the molecular profiling of TNBC patients. Several biomarkers have been found that are targets for the precision therapy in TNBC, such as EGFR, VGFR, TP53, interleukins, insulin-like growth factor binding proteins, c-MET, androgen receptor, BRCA1, glucocorticoid, PTEN, ALDH1, etc. This review discusses the various candidate biomarkers identified in the treatment of TNBC along with the evidence supporting their use. It was established that nanoparticles had been considered a multifunctional system for delivering therapeutics to target sites with increased precision. Here, we also discuss the role of biomarkers in nanotechnology translation in TNBC therapy and management.

Role of p53 in breast cancer progression: An insight into p53 targeted therapy

The transcription factor p53 is an important regulator of a multitude of cellular processes. In the presence of genotoxic stress, p53 is activated to facilitate DNA repair, cell cycle arrest, and apoptosis. In breast cancer, the tumor suppressive activities of p53 are frequently inactivated by either the overexpression of its negative regulator MDM2, or mutation which is present in 30-35% of all breast cancer cases. Notably, the frequency of p53 mutation is highly subtype dependent in breast cancers, with majority of hormone receptor-positive or luminal subtypes retaining the wild-type p53 status while hormone receptor-negative patients predominantly carry p53 mutations with gain-of-function oncogenic activities that contribute to poorer prognosis. Thus, a two-pronged strategy of targeting wild-type and mutant p53 in different subtypes of breast cancer can have clinical relevance. The development of p53-based therapies has rapidly progressed in recent years, and include unique small molecule chemical inhibitors, stapled peptides, PROTACs, as well as several genetic-based approaches using vectors and engineered antibodies. In this review, we highlight the therapeutic strategies that are in pre-clinical and clinical development to overcome p53 inactivation in both wild-type and mutant p53-bearing breast tumors, and discuss their efficacies and limitations in pre-clinical and clinical settings.

CDK14 inhibition reduces mammary stem cell activity and suppresses triple negative breast cancer progression

The Wnt/β-catenin signaling pathway plays an important role in regulating mammary organogenesis and oncogenesis. However, therapeutic methods targeting the Wnt pathway against breast cancer have been limited. To address this challenge, we investigate the function of cyclin-dependent kinase 14 (CDK14), a member of the Wnt signaling pathway, in mammary development and breast cancer progression. We show that CDK14 is expressed in the mammary basal layer and elevated in triple negative breast cancer (TNBC). CDK14 knockdown reduces the colony-formation ability and regeneration capacity of mammary basal cells and inhibits the progression of murine MMTV-Wnt-1 basal-like mammary tumor. CDK14 knockdown or pharmacological inhibition by FMF-04-159-2 suppresses the progression and metastasis of TNBC. Mechanistically, CDK14 inhibition inhibits mammary regeneration and TNBC progression by attenuating Wnt/β-catenin signaling. These findings highlight the significance of CDK14 in mammary development and TNBC progression, shedding light on CDK14 as a promising therapeutic target for TNBC.

Targeting the Heterogeneous Genomic Landscape in Triple-Negative Breast Cancer through Inhibitors of the Transcriptional Machinery

Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer defined by lack of the estrogen, progesterone and human epidermal growth factor receptor 2. Although TNBC tumors contain a wide variety of oncogenic mutations and copy number alterations, the direct targeting of these alterations has failed to substantially improve therapeutic efficacy. This efficacy is strongly limited by interpatient and intratumor heterogeneity, and thereby a lack in uniformity of targetable drivers. Most of these genetic abnormalities eventually drive specific transcriptional programs, which may be a general underlying vulnerability. Currently, there are multiple selective inhibitors, which target the transcriptional machinery through transcriptional cyclin-dependent kinases (CDKs) 7, 8, 9, 12 and 13 and bromodomain extra-terminal motif (BET) proteins, including BRD4. In this review, we discuss how inhibitors of the transcriptional machinery can effectively target genetic abnormalities in TNBC, and how these abnormalities can influence sensitivity to these inhibitors. These inhibitors target the genomic landscape in TNBC by specifically suppressing MYC-driven transcription, inducing further DNA damage, improving anti-cancer immunity, and preventing drug resistance against MAPK and PI3K-targeted therapies. Because the transcriptional machinery enables transcription and propagation of multiple cancer drivers, it may be a promising target for (combination) treatment, especially of heterogeneous malignancies, including TNBC.

Elevation of effective p53 expression sensitizes wild-type p53 breast cancer cells to CDK7 inhibitor THZ1

Background

The cyclin-dependent kinase 7 (CDK7) inhibitor THZ1 represses multiple cancer cells. However, its tumor-repressive efficiency in wild-type p53 breast cancer cells remains controversial.

Methods

We conducted various assays, including CCK8, colony formation, flow cytometry, western blotting, and lactate dehydrogenase release detection, to clarify whether p53 elevation sensitizes breast cancer cells to THZ1.

Results

We found that upregulating functional p53 contributes to the increased sensitivity of breast cancer cells to THZ1. Increased THZ1 sensitivity requires active p53 and an intact p53 pathway, which was confirmed by introducing exogenous wild-type p53 and the subsequent elevation of THZ1-mediated tumor suppression in breast cancer cells carrying mutant p53. We confirmed that p53 accumulates in the nucleus and mitochondria during cell death. Furthermore, we identified extensive transcriptional disruption, rather than solely CDK7 inhibition, as the mechanism underlying the nutlin-3 and THZ1-induced death of breast cancer cells. Finally, we observed the combined nutlin-3 and THZ1 treatment amplified gasdermin E cleavage.

Conclusion

Enhanced sensitivity of breast cancer cells to THZ1 can be achieved by increasing effective p53 expression. Our approach may serve as a potential treatment for patients with breast cancer resistant to regular therapies.

p53-GSDME Elevation: A Path for CDK7 Inhibition to Suppress Breast Cancer Cell Survival

Higher cyclin-dependent kinase (CDK7) expression is a character of breast cancer and indicates poor prognosis. Inhibiting CDK7 exhibited effective cancer cell suppression which implies the potential of CDK7 inhibition to be a method for anti-cancer treatment. Our study aimed to explore a novel mechanism of CDK7 inhibition for suppressing breast cancer cell survival. Here, we proved inhibiting CDK7 repressed breast cancer cell proliferation and colony formation and increased the apoptotic cell rate, with p53 and GSDME protein level elevation. When p53 was suppressed in MCF-7 cells, the decline of GSDME expression and associated stronger proliferation and colony formation could be observed. Since downregulation of GSDME was of benefit to breast cancer cells, p53 inhibition blocked the elevation of GSDME induced by CDK7 inhibition and retrieved cells from the tumor suppressive effect of CDK7 inhibition. Therefore, CDK7 inhibition exerted a negative effect on breast cancer cell proliferation and colony formation in a p53–GSDME dependent manner. These results revealed the CDK7–p53–GSDME axis could be a pathway affecting breast cancer cell survival.