Decreased CDK10 expression correlates with lymph node metastasis and predicts poor outcome in breast cancer patients - a short report

Downregulated CDK10 promotes cancer progression and radioresistance in lung cancer through activating the JNK/c-Jun signaling pathway

Lung cancer is one of the most significant malignancies, with both high morbidity and mortality. CDK10 is closely related to cancer progression and metastasis. However, its role in lung cancer radioresistance demands further clarification. In this study, we demonstrated that CDK10 was downregulated in lung cancer tissues, and CDK10 expression level was associated with the clinical prognosis in lung cancer patients. We also found that silencing CDK10 promoted lung cancer cell proliferation, migration, and radioresistance. We further verified that silencing CDK10 facilitated the activation of JNK/c-Jun signaling, and c-Jun depletion could reverse the effects of CDK10 knockdown in lung cancer cells. Our findings revealed that CDK10 plays an important role in cell growth and radioresistance by inhibiting JNK/c-Jun signaling pathway in lung cancer. Therefore, CDK10 might be a promising therapeutic target in lung cancer. [BMB Reports 2024; 57(7): 336-341].

CDK10 suppresses metastasis of lung adenocarcinoma through inhibition of the ETS2/c-Raf/p-MEK/p-ERK signaling loop

The repertoire of aberrant signaling underlying the pathogenesis of lung adenocarcinoma remains largely uncharacterized, which precludes an efficient therapy for these patients, especially when distant metastasis occurs. Cyclin-dependent kinase 10 (CDK10) has been reported to modulate the progression of malignant tumors; however, contradictory effects have been found among different types of malignant tumors. In the present study, we found that CDK10 was downregulated in lung adenocarcinoma compared with the paired adjacent normal lung tissue, and lower expression level of CDK10 was associated with more frequent N2 staged lymph node and distant metastasis, higher TNM stage, and shorter overall survival. Further study indicated that CDK10 inhibited the migration and invasion abilities with no impact on the proliferation of lung adenocarcinoma cells. Mechanistically, CDK10 could bind to and promote the degradation of ETS2, a transcription factor for C-RAF and MMP2/9, thereby inactivating the downstream c-Raf/p-MEK/p-ERK pathway that drives epithelial-mesenchymal transition and impairing the expression of matrix metalloproteinases involved in cell invasion. In addition, the p-MEK/p-ERK pathway conducts a positive feedback regulation on the expression of ETS2. Knockdown of CDK10 in human lung adenocarcinoma cells significantly promoted the formation of metastatic foci in lungs in a xenograft mouse model. In conclusion, CDK10 suppresses metastasis of lung adenocarcinoma by disrupting the ETS2/c-Raf/p-MEK/p-ERK/ETS2 signaling and MMP2/9, providing a new therapeutic target for the treatment of lung adenocarcinoma with metastasis.

Copy number variants landscape of multiple cancers and clinical applications based on NGS gene panel

BACKGROUND

The rapid adoption of next-generation sequencing in clinical oncology has enabled detection of molecular biomarkers which are shared between multiple tumour types. Intra-tumour heterogeneity is a mechanism of therapeutic resistance and therefore an important clinical challenge. However, the tumour-related copy number variants (CNVs), as key regulators of cancer origination, development, and progression, across various types of cancers are poorly understood.

METHODS

We performed pan-cancer CNV analysis of cancer-related genes in 15 types of cancers including 1438 cancerous patients by next-generation sequencing using a commercially available pan-cancer panel (Onco PanScan™). Downstream bioinformatics analysis was performed in order to detect CNVs, cluster analysis of the found CNVs, and comparison of the frequency of gained CNVs between different types of cancers. LASSO analysis was used for identification of the most important CNVs.

RESULTS

We also identified 523 CNVs among which 16 CNVs were common while 22 CNVs were caner-specific CNVs. Meanwhile, FAM58A was most commonly found in all studied cancers in this study and significant differences were found in FAM58A between female and male patients (p = .001). Common CNVs, such as FOXA1, NFKBIA, HEY1, MECOM, CHD7, AGO2, were mutated in 6.79%, 8.45%, 7.51%, 6.43%, 7.59%, 8.16% of tumours, while most of these mutations have proven roles in positive regulation of transcription from RNA polymerase II promoter. 11 features including sex, DIS3, EPHB1, ERBB2, FLT1, HCK, KEAP1, MYD88, PARP3, TBX3, and TOP2A were found as the key features for classification of cancers using CNVs.

CONCLUSION

The 16 common CNVs between cancers can be used to identify the target of pan-cancer drug design and targeted therapies. Additionally, 22 caner-specific CNVs can be used as unique diagnostic markers for each cancer type.

Regulation of eukaryotic protein kinases by Pin1, a peptidyl-prolyl isomerase

The peptidyl-prolyl isomerase Pin1 cooperates with proline-directed kinases and phosphatases to regulate multiple oncogenic pathways. Pin1 specifically recognizes phosphorylated Ser/Thr-Pro motifs in proteins and catalyzes their cis-trans isomerization. The Pin1-catalyzed conformational changes determine the stability, activity, and subcellular localization of numerous protein substrates. We conducted a survey of eukaryotic protein kinases that are regulated by Pin1 and whose Pin1 binding sites have been identified. Our analyses reveal that Pin1 target sites in kinases do not fall exclusively within the intrinsically disordered regions of these enzymes. Rather, they fall into three groups based on their location: (i) within the catalytic kinase domain, (ii) in the C-terminal kinase region, and (iii) in regulatory domains. Some of the kinases downregulated by Pin1 activity are tumor-suppressing, and all kinases upregulated by Pin1 activity are functionally pro-oncogenic. These findings further reinforce the rationale for developing Pin1-specific inhibitors as attractive pharmaceuticals for cancer therapy.

Attenuated ZHX3 expression is predictive of poor outcome for liver cancer: Indication for personalized therapy

The zinc-fingers and homeoboxes (ZHX) family members have been characterized as master regulators in cancer initiation and development. The present study performed in silico data-mining with publicly available datasets and immunohistochemistry to assess the expression status of ZHX factors and the corresponding prognostic implications in liver cancer. Increased ZHX3 mRNA expression was associated with favorable overall survival in patients with liver cancer. Subgroups analyses revealed a significant association between the expression of ZHX factors and outcomes in select patient cohorts. Immunohistochemical analysis supported that ZHX3 expression was an independent prognostic indicator for patient survival. These results suggested that dysregulation of ZHX factors is involved in disease progression and ZHX3 expression may serve as a prognostic biomarker for liver cancer.

Functional characterization of the human Cdk10/Cyclin Q complex

Cyclin-dependent kinases (CDKs) are key players in cell cycle regulation and transcription. The CDK-family member Cdk10 is important for neural development and can act as a tumour suppressor, but the underlying molecular mechanisms are largely unknown. Here, we provide an in-depth analysis of Cdk10 substrate specificity and function. Using recombinant Cdk10/CycQ protein complexes, we characterize RNA pol II CTD, c-MYC and RB1 as in vitro protein substrates. Using an analogue-sensitive mutant kinase, we identify 89 different Cdk10 phosphosites in HEK cells originating from 66 different proteins. Among these, proteins involved in cell cycle, translation, stress response, growth signalling, as well as rRNA, and mRNA transcriptional regulation, are found. Of a set of pan-selective CDK- and Cdk9-specific inhibitors tested, all inhibited Cdk10/CycQ at least five times weaker than their proposed target kinases. We also identify Cdk10 as an in vitro substrate of Cdk1 and Cdk5 at multiple sites, allowing for a potential cross-talk between these CDKs. With this functional characterization, Cdk10 adopts a hybrid position in both cell cycle and transcriptional regulation.

Dysregulation of ECRG4 is associated with malignant properties and of prognostic importance in human gastric cancer

BACKGROUND

We have previously characterized esophageal carcinoma-related gene 4 (ECRG4) as a novel tumor suppressor gene, which is frequently inactivated in nasopharyngeal carcinoma and breast cancer. Nevertheless, the expression status and prognostic significance of ECRG4 maintain elusive in human gastric cancer. Herein, we examined ECRG4 expression profile in gastric cancer and assessed its association with clinicopathological characteristics and patient survival.

METHODS

Online data mining, real-time RT-PCR and immunohistochemistry were employed to determined ECRG4 expression at transcriptional and protein levels in tumors vs. noncancerous tissues. Statistical analyses including the Kaplan-Meier survival analysis and the Cox hazard model were utilized to detect the impact on clinical outcome. Moreover, ECRG4 expression was silenced in gastric cancer SGC7901 cells, and cell proliferation, colony formation and invasion assays were carried out.

RESULTS

ECRG4 mRNA and protein levels were obviously downregulated in cancer tissues than noncancerous tissues. Statistical analyses demonstrated that low ECRG4 expression was found in 34.5% (58/168) of primary gastric cancer tissues, which was associated with higher histological grade (P= 0.018), lymph node metastasis (P= 0.011), invasive depth (P= 0.020), advanced tumor stage (P= 0.002) and poor overall survival (P< 0.001). Multivariate analysis showed ECRG4 expression is an independent prognostic predictor (P< 0.001). Silencing ECRG4 expression promoted gastric cancer cell growth and invasion. Western blot analysis revealed the anti-metastatic functions of ECRG4 by downregulating of E-cadherin and α-Catenin, as well as upregulating N-cadherin and Vimentin.

CONCLUSIONS

Our observations reveal that ECRG4 expression is involved in gastric cancer pathogenesis and progression, and may serve as a candidate prognostic biomarker for this disease.

CDK10 in Gastrointestinal Cancers: Dual Roles as a Tumor Suppressor and Oncogene

Cyclin-dependent kinase 10 (CDK10) is a CDC2-related serine/threonine kinase involved in cellular processes including cell proliferation, transcription regulation and cell cycle regulation. CDK10 has been identified as both a candidate tumor suppressor in hepatocellular carcinoma, biliary tract cancers and gastric cancer, and a candidate oncogene in colorectal cancer (CRC). CDK10 has been shown to be specifically involved in modulating cancer cell proliferation, motility and chemosensitivity. Specifically, in CRC, it may represent a viable biomarker and target for chemoresistance. The development of therapeutics targeting CDK10 has been hindered by lack a specific small molecule inhibitor for CDK10 kinase activity, due to a lack of a high throughput screening assay. Recently, a novel CDK10 kinase activity assay has been developed, which will aid in the development of small molecule inhibitors targeting CDK10 activity. Discovery of a small molecular inhibitor for CDK10 would facilitate further exploration of its biological functions and affirm its candidacy as a therapeutic target, specifically for CRC.

Low expression of CDK12 in gastric cancer is correlated with advanced stage and poor outcome

BACKGROUND

Cyclin-dependent kinase 12 (CDK12) belongs to the cyclin-dependent kinase (CDK) family, modulating multiple cellular functions including DNA damage response (DDR), development and cellular differentiation, transcription, mRNA processing, splicing and pre-mRNA processing. CDK12 has been reported as both tumor suppressor and oncogene in various kinds of tumor. The function of CDK12 in gastric cancer (GC) remains unclear.

METHODS/RESULTS

CDK12 mRNA expression was decreased in GC compared with non-tumor tissue based on GEO database. Also, low mRNA expression of CDK12 was detected in GC cell lines by qPCR. Similarly, CDK12 protein expression was also reduced in GC tissues compared with adjacent non-tumor tissues in 177 GC patients as shown by immunohistochemistry. Low expression of CDK12 was associated with organ metastasis, poorly differentiated adenocarcinoma and advanced stage. Consistent with human protein atlas database analysis, Low expression of CDK12 was correlated with worse overall survival (P < 0.001). Multivariate Cox regression indicated that low expression of CDK12 was an independent prognostic factor for GC patients (P < 0.001). Finally, a gene set enrichment analysis was performed to detect underlying internal mechanisms and biological processes.

CONCLUSIONS

CDK12 is down-regulated in GC and its expression is negatively correlated with advanced stage, poorly differentiated adenocarcinoma and poor outcomes. Our findings suggest that CDK12 may be a potential tumor suppressor in GC.

The Roles of Cyclin-Dependent Kinases in Cell-Cycle Progression and Therapeutic Strategies in Human Breast Cancer

Cyclin-dependent kinases (CDKs) are serine/threonine kinases whose catalytic activities are regulated by interactions with cyclins and CDK inhibitors (CKIs). CDKs are key regulatory enzymes involved in cell proliferation through regulating cell-cycle checkpoints and transcriptional events in response to extracellular and intracellular signals. Not surprisingly, the dysregulation of CDKs is a hallmark of cancers, and inhibition of specific members is considered an attractive target in cancer therapy. In breast cancer (BC), dual CDK4/6 inhibitors, palbociclib, ribociclib, and abemaciclib, combined with other agents, were approved by the Food and Drug Administration (FDA) recently for the treatment of hormone receptor positive (HR+) advanced or metastatic breast cancer (A/MBC), as well as other sub-types of breast cancer. Furthermore, ongoing studies identified more selective CDK inhibitors as promising clinical targets. In this review, we focus on the roles of CDKs in driving cell-cycle progression, cell-cycle checkpoints, and transcriptional regulation, a highlight of dysregulated CDK activation in BC. We also discuss the most relevant CDK inhibitors currently in clinical BC trials, with special emphasis on CDK4/6 inhibitors used for the treatment of estrogen receptor-positive (ER+)/human epidermal growth factor 2-negative (HER2−) M/ABC patients, as well as more emerging precise therapeutic strategies, such as combination therapies and microRNA (miRNA) therapy.

Development of a CDK10/CycM in vitro Kinase Screening Assay and Identification of First Small-Molecule Inhibitors

Cyclin-dependent kinases (CDKs) constitute a family of 20 serine/threonine protein kinases that play pivotal roles in the regulation of numerous important molecular and cellular processes. CDKs have long been considered promising therapeutic targets in a variety of pathologies, and the recent therapeutic success of CDK4/6 inhibitors in breast cancers has renewed interest in their therapeutic potential. Small-molecule inhibitors have been identified for every human CDK, except for CDK10. The only recent discovery of an activating cyclin (CycM) for CDK10 enabled us to identify its first phosphorylation substrates and gain insights into its biological functions. Yet, our knowledge of this kinase remains incomplete, despite it being the only member of its family that causes severe human developmental syndromes, when mutated either on the cyclin or the CDK moiety. CDK10 small-molecule inhibitors would be useful in exploring the functions of this kinase and gauging its potential as a therapeutic target for some cancers. Here, we report the identification of an optimized peptide phosphorylation substrate of CDK10/CycM and the development of the first homogeneous, miniaturized CDK10/CycM in vitro kinase assay. We reveal the ability of known CDK inhibitors, among which clinically tested SNS-032, riviciclib, flavopiridol, dinaciclib, AZD4573 and AT7519, to potently inhibit CDK10/CycM. We also show that NVP-2, a strong, remarkably selective CDK9 inhibitor is an equally potent CDK10/CycM inhibitor. Finally, we validate this kinase assay for applications in high-throughput screening campaigns to discover new, original CDK10 inhibitors.

Label-free whole-colony imaging and metabolic analysis of metastatic pancreatic cancer by an autoregulating flexible optical system

Cancer metastasis is a Gordian knot for tumor diagnosis and therapy. Many studies have demonstrated that metastatic processes are inevitably affected by the tumor microenvironment. Histopathology is used universally as the gold standard for cancer diagnosis despite the lengthy preparation process and invasiveness.

Methods: Here, we introduced a supercontinuum and super-wide-tuning integrated multimodal platform, which combines the confocal, nonlinear and fluorescence lifetime microscopy with autoregulations, for label-free evaluation of fresh tissue and pathological sections. Based on various automated tunable lasers, synchronized and self-adjusting components and eight fast switching detection channels, the system features fast, large-field and subcellular-scale imaging of exogenous and endogenous fluorophores, nonlinear coherent scattering and lifetime contrast.

Results: With such an integrated multi-dimensional system, we searched the metastatic region by two-photon and three-photon excited autofluorescence, analyzed the cancer invasion by second harmonic generation and revealed the affected cellular metabolism by phasor-lifetime. We demonstrated the flexible measurement of multiple nonlinear modalities at NIR I and II excitation with a pre-compensation for group delay dispersion of ~7,000 fs² and low power of <40 mW, and of dual autofluorescence lifetime decays for phasor approach to decompose cancer-associated and disassociated components. This significantly revealed the metastatic and metabolic optical signatures of the whole colony of pancreatic cancers.

Conclusion: The synergistic effect of the system demonstrates the great potential to translate this technique into routine clinical applications, particularly for large-scale and quantitative studies of metastatic colonization.

Decreased ST2 expression is associated with gastric cancer progression and pathogenesis

Gastric cancer is a type of cancer with increasing incidence and high mortality rates, but molecular biomarkers of diagnostic and therapeutic value are currently lacking. The aim of the present study was to examine the expression pattern of the interleukin 1 receptor-like 1 (ST2) protein and assess its clinicopathological significance in gastric cancer. Western blot analysis of 12 gastric cancer specimens and paired adjacent tissues demonstrated that the protein levels of 2 isoforms of ST2, soluble secreted ST2 and the ST2 variant without the third immunoglobulin motif and splicing in the C-terminal, were markedly decreased in cancer tissues compared with non-cancerous tissues. Immunohistochemical analysis demonstrated that ST2 protein expression was markedly decreased in primary gastric cancer tissues (39.1%, 90/230) compared with adjacent non-cancerous tissues (60.7%, 54/89) (P<0.05). Statistical analysis demonstrated that decreased ST2 expression was significantly associated with advanced tumor node metastasis stage (P<0.001) and tumor differentiation (P<0.001). These data suggest that ST2 protein may be a valuable biomarker of gastric cancer progression and pathogenesis.

Attenuated ZHX3 expression serves as a potential biomarker that predicts poor clinical outcomes in breast cancer patients

Background

The ZHX family has recently been in the spotlight as an integrator and an indispensable node in carcinogenesis, whose expression is frequently dysregulated in multiple cancers. The current study provides a novel investigation of the expression profiles of ZHX factors in breast cancer.

Materials and methods

The mRNA levels of ZHXs and follow-up periods in breast cancer patients were mined through the Oncomine, Cancer Cell Line Encyclopedia, bc-GenExMiner, cBioPortal and Kaplan–Meier plotter databases. In addition, ZHX3 protein expression was examined in 98 primary tumor samples by immunohistochemistry to investigate its association with clinicopathological parameters and patient outcomes.

Results

We found that the transcriptional levels of ZHX1, ZHX2 and ZHX3 were not significantly altered in tumor tissues compared with those in nontumor tissues. ZHX2 and ZHX3 mRNA levels were observed to be positively correlated with estrogen receptor and progesterone receptor expression, while ZHX2 mRNA levels were negatively associated with HER2 expression. Survival analyses revealed that high mRNA levels of ZHX2 and ZHX3 correlated with better overall survival in patients with breast cancer. Immunohistochemical analysis revealed that patients with decreased ZHX3 protein levels had poorer outcomes. Multivariate analysis exhibited that ZHX3 expression may serve as an independent high-risk prognostic predictor.

Conclusion

Dysregulated expression of ZHXs may be involved in the progression of breast cancer and could serve as a novel biomarker and potential target for breast cancer.

Gene expression imputation identifies candidate genes and susceptibility loci associated with cutaneous squamous cell carcinoma

Cutaneous squamous cell carcinoma (cSCC) is a common skin cancer with genetic susceptibility loci identified in recent genome-wide association studies (GWAS). Transcriptome-wide association studies (TWAS) using imputed gene expression levels can identify additional gene-level associations. Here we impute gene expression levels in 6891 cSCC cases and 54,566 controls in the Kaiser Permanente Genetic Epidemiology Research in Adult Health and Aging (GERA) cohort and 25,558 self-reported cSCC cases and 673,788 controls from 23andMe. In a discovery-validation study, we identify 19 loci containing 33 genes whose imputed expression levels are associated with cSCC at false discovery rate < 10% in the GERA cohort and validate 15 of these candidate genes at Bonferroni significance in the 23andMe dataset, including eight genes in five novel susceptibility loci and seven genes in four previously associated loci. These results suggest genetic mechanisms contributing to cSCC risk and illustrate advantages and disadvantages of TWAS as a supplement to traditional GWAS analyses.

Genetic loci linked to susceptibility for the common skin cancer cutaneous squamous cell carcinoma (cSCC) have been identified by genome wide association studies (GWAS). Here, the authors impute gene expression levels from GWAS data to perform a transcriptome wide association study (TWAS), identifying five novel genetic loci linked to cSCC susceptibility.

Cyclin‑dependent kinase 10 prevents glioma metastasis via modulation of Snail expression

Cyclin‑dependent kinase 10 (CDK10) has been indicated to be a candidate tumor suppressor in multiple cancer types. However, to the best of the authors' knowledge, its biological and regulatory functions in glioma have not been previously reported. In the present study, it was demonstrated that overexpression of CDK10 inhibited glioma cell proliferation and metastasis. By contrast, knockdown of CDK10 expression promoted these malignant phenotypes. It was additionally indicated that dysregulated CDK10 expression was associated with epithelial‑mesenchymal transition (EMT) and that it regulated the expression of zinc finger protein SNAI1 (Snail). Furthermore, silencing Snail expression rescued EMT phenotypes induced by CDK10 knockdown, suggesting that Snail may be involved in the mechanistic association between CDK10 and EMT. The present study illustrated that downregulation of CDK10 expression activated Snail‑driven EMT and consequently promoted glioma metastasis, suggesting that CDK10 may serve as a potential molecular target for glioma therapy.

The awakening of the CDK10/Cyclin M protein kinase

Cyclin-dependent kinases (CDKs) play important roles in the control of fundamental cellular processes. Some of the most characterized CDKs are considered to be pertinent therapeutic targets for cancers and other diseases, and first clinical successes have recently been obtained with CDK inhibitors. Although discovered in the pre-genomic era, CDK10 attracted little attention until it was identified as a major determinant of resistance to endocrine therapy for breast cancer. In some studies, CDK10 has been shown to promote cell proliferation whereas other studies have revealed a tumor suppressor function. The recent discovery of Cyclin M as a CDK10 activating partner has allowed the unveiling of a protein kinase activity against the ETS2 oncoprotein, whose degradation is activated by CDK10/Cyclin M-mediated phosphorylation. CDK10/Cyclin M has also been shown to repress ciliogenesis and to maintain actin network architecture, through the phoshorylation of the PKN2 protein kinase and the control of RhoA stability. These findings shed light on the molecular mechanisms underlying STAR syndrome, a severe human developmental genetic disorder caused by mutations in the Cyclin M coding gene. They also pave the way to a better understanding of the role of CDK10/Cyclin M in cancer.

Downregulated CDK10 expression in gastric cancer: Association with tumor progression and poor prognosis

The tumor suppressor characteristics of cyclin‑dependent kinase 10 (CDK10) in nasopharyngeal carcinoma and breast cancer have been previously demonstrated. In the present study the expression status of CDK10 and its prognostic significance in gastric cancer was determined, as well as its role in cell proliferation and invasion. Immunoblot analysis revealed that CDK10 protein expression was notably decreased in gastric cancer compared with normal tissues. Immunohistochemistry demonstrated that the loss of CDK10 expression, which was observed in 50.8% of primary gastric cancer tissues (n=128), significantly correlated with advanced tumor stage (P<0.001), frequent lymph node metastasis (P<0.001), distant metastasis (P=0.013), tumor differentiation (P=0.004) and unfavorable overall survival (P<0.001). Multivariate analysis suggested that CDK10 expression may serve as an independent prognostic predictor (P=0.001) for the progression of gastric cancer. In addition, ectopic CDK10 expression inhibited gastric cancer cell proliferation, migration and invasion, while knockdown of CDK10 promoted these phenotypes. Collectively, the results of the present study indicated that CDK10 expression may serve as a novel prognostic biomarker that holds therapeutic promise for gastric cancer.

The role of lymphangiogenesis and angiogenesis in tumor metastasis

BACKGROUND

Metastasis is the main cause of mortality in cancer patients. Two major routes of cancer cell spread are currently being recognized: dissemination via blood vessels (hematogenous spread) and dissemination via the lymphatic system (lymphogenous spread). Here, our current knowledge on the role of both blood and lymphatic vessels in cancer cell metastasis is summarized. In addition, I will discuss why cancer cells select one or both of the two routes to disseminate and I will provide a short description of the passive and active models of intravasation. Finally, lymphatic vessel density (LVD), blood vessel density (BVD), interstitial fluid pressure (IFP) and tumor hypoxia, as well as regional lymph node metastasis and the recently discovered primo vascular system (PVS) will be highlighted as important factors influencing tumor cell motility and spread and, ultimately, clinical outcome.

CONCLUSIONS

Lymphangiogenesis and angiogenesis are important phenomena involved in the spread of cancer cells and they are associated with a poor prognosis. It is anticipated that new discoveries and advancing knowledge on these phenomena will allow an improvement in the treatment of cancer patients.

A novel curcumin-like dienone induces apoptosis in triple-negative breast cancer cells

PURPOSE

According to the World Health Organization (WHO), breast cancer is the most common cancer affecting women worldwide. In the USA ~12.3 % of all women are expected to be diagnosed with various types of breast cancer, exhibiting varying degrees of therapeutic response rates. Therefore, the identification of novel anti-breast cancer drugs is of paramount importance.

METHODS

The 1,5-diaryl-3-oxo-1,4-pentadienyl pharmacophore was incorporated into a number of cytotoxins. Three of the resulting dienones, 2a, 2b and 2c, were tested for their anti-neoplastic potencies in a variety of human breast cancer-derived cell lines, including the triple negative MDA-MB-231 cell line and its metastatic variant, using a live-cell bio-imaging method. Special emphasis was put on dienone 2c, since its anti-cancer activity and its mode of inflicting cell death have so far not been reported.

RESULTS

We found that all three dienones exhibited potent cytotoxicities towards the breast cancer-derived cell lines tested, whereas significantly lower toxicities were observed towards the non-cancerous human breast cell line MCF-10A. The dienones 2b and 2c exhibited the greatest selective cytotoxicity at submicromolar concentration levels. We found that these two dienones induced phosphatidylserine externalization in MDA-MB-231 cells in a concentration-dependent manner, suggesting that their cytotoxic effect might be mediated by apoptosis. This possibility was confirmed by our observation that the dienone 2c can induce mitochondrial depolarization, caspase-3 activation, cell cycle disruption and DNA fragmentation in MDA-MB-231 cells.

CONCLUSION

Our findings indicate that dienone 2c uses the mitochondrial/intrinsic pathway to inflict apoptosis in triple negative MDA-MB-231 breast cancer-derived cells. This observation warrants further assessment of dienone 2c as a potential anti-breast cancer drug.