Targeting cyclin-dependent kinase 1 (CDK1) but not CDK4/6 or CDK2 is selectively lethal to MYC-dependent human breast cancer cells

Extracellular vesicle-mediated delivery of miR-766-3p from bone marrow stromal cells as a therapeutic strategy against colorectal cancer

OBJECTIVE

As colorectal cancer (CRC) remains one of the leading causes of cancer-related deaths, understanding novel therapeutic mechanisms is crucial. This research focuses on the role of extracellular vesicles (EVs) from bone marrow stromal cells (BMSCs) in delivering miR-766-3p to CRC cells, targeting the MYC/CDK2 signaling axis.

METHODS

Differentially expressed genes between BMSCs-EVs and CRC were identified using the Gene Expression Omnibus database. miR-766-3p target genes were predicted via TargetScan and RNAInter, with protein interactions analyzed using the STRING database. The analysis included RT-qPCR and Western blot on samples from 52 CRC patients. Characterization of BMSCs-EVs was followed by their functional assessment on CRC cell lines and the normal colon cell line CCD-18CO, evaluating cellular uptake, proliferation, migration, invasion, and apoptosis.

RESULTS

miR-766-3p was confirmed in BMSCs-EVs and found underexpressed in CRC. BMSCs-EVs transported miR-766-3p to CRC cells, inhibiting their proliferation, migration, and invasion while promoting apoptosis. miR-766-3p targeted MYC, leading to decreased CDK2 transcription. Overexpression of MYC in HCT-116 cells counteracted these effects. In vivo studies showed that BMSCs-EVs carrying miR-766-3p hindered tumor growth.

CONCLUSION

The study demonstrates the efficacy of BMSCs-EVs in delivering miR-766-3p to CRC cells, leading to the suppression of the MYC/CDK2 signaling pathway and hindering cancer progression.

Discovery of Potential Inhibitors of CDK1 by Integrating Pharmacophore-Based Virtual Screening, Molecular Docking, Molecular Dynamics Simulation Studies, and Evaluation of Their Inhibitory Activity

The ability of CDK1 to compensate for the absence of other cell cycle CDKs poses a great challenge to treat cancers that overexpress these proteins. Despite several studies focusing on the area, there are no FDA-approved drugs selectively targeting CDK1. Here, the study aimed to develop potential CDK1 selective inhibitors through drug repurposing and leveraging the structural insights provided by the hit molecules generated. Approximately 280,000 compounds from DrugBank, Selleckchem, Otava and an in-house library were screened initially based on fit values using 3D QSAR pharmacophores built for CDK1 and subsequently through Lipinski, ADMET, and TOPKAT filters. 10,310 hits were investigated for docking into the binding site of CDK1 determined using the crystal structure of human CDK1 in complex with NU6102. The best 55 hits with better docking scores were further analyzed, and 12 hits were selected for 100 ns MD simulations followed by binding energy calculations using the MM-PBSA method. Finally, 10 hit molecules were tested in an in vitro CDK1 Kinase inhibition assay. Out of these, 3 hits showed significant CDK1 inhibitory potential with IC50 < 5 μM. These results indicate these compounds can be used to develop subtype-selective CDK1 inhibitors with better efficacy and reduced toxicities in the future.

On discovery of novel hub genes for ER+ and TN breast cancer types through RNA seq data analyses and classification models

Breast cancer (BC) is a malignant neoplasm which is classified into various types defined by underlying molecular factors such as estrogen receptor positive (ER+), progesterone receptor positive (PR+), human epidermal growth factor positive (HER2+) and triple negative (TNBC). Early detection of ER+ and TNBC is crucial in the choice of diagnosis and appropriate treatment strategy. Here we report the key genes associated to ER+ and TNBC using RNA-Seq analysis and machine learning models. Three ER+ and TNBC RNA seq datasets comprising 164 patients in-toto were selected for standard NGS hierarchical data processing and data analyses protocols. Enrichment pathway analysis and network analysis was done and finally top hub genes were identified. To come with a reliable classifier which could distinguish the distinct transcriptome patterns associated to ER+ and TNBC, ML models were built employing Naïve Bayes, SVM and kNN. 1730 common DEG's exhibiting significant logFC values with 0.05 p-value threshold were identified. A list of top ten hub genes were screened on the basis of maximal clique centrality (MCC) which included CDC20, CDK1, BUB1, AURKA, CDCA8, RRM2, TTK, CENPF, CEP55 and NDC80.These genes were found to be involved in crucial cell cycle pathways. k-Nearest Neighbor (kNN) model was observed to be best classifier with accuracy 84%, specificity 66% and sensitivity 95% to differentiate between ER+ and TNBC RNA-Seq transcriptomes. Our screened list of 10 hub genes can thus help unearth novel molecular signatures implicated in ER+ and TNBC onset, prognosis and design of novel protocols for breast cancer diagnostics and therapeutics.

Favipiravir, an antiviral drug, in combination with tamoxifen exerts synergistic effect in tamoxifen-resistant breast cancer cells via hTERT inhibition

Tamoxifen (TAM) is one of the most successful treatments for breast cancer; however, TAM resistance continues to be a significant barrier. TAM resistance has been reported to be associated with increased expression of human telomerase reverse transcriptase (hTERT). This enzyme shares structural similarity with RNA-dependent RNA polymerase (RdRp) enzyme of RNA viruses, suggesting that RdRp inhibitors may also inhibit hTERT. Favipiravir (FAV) is an antiviral drug that inhibits RdRp of RNA viruses. Thus, we propose that FAV may also elicit an antitumor effect by suppressing hTERT. This study aimed to investigate the effect of FAV and TAM on TAM-resistant breast cancer (TAMR-1). The cell viabilities were determined. The levels of CDK1/ hTERT, in addition to regulators of hTERT-targeted signaling pathways were measured. Apoptosis, migration, and cell cycle distribution were also determined. Our data revealed that the combination of TAM and FAV suppressed cell proliferation synergistically (CI < 1) and resulted in a significant change in cell migration and apoptosis. Indeed, this was associated with reduced levels of hTERT and CDK1 and shift in the cell cycle distribution. Our findings suggest that the TAM/FAV combination exhibits synergistic effects against TAMR-1 human breast cancer cells by targeting hTERT.

In Silico Mixed Ligand/Structure-Based Design of New CDK-1/PARP-1 Dual Inhibitors as Anti-Breast Cancer Agents

CDK-1 and PARP-1 play crucial roles in breast cancer progression. Compounds acting as CDK-1 and/or PARP-1 inhibitors can induct cell death in breast cancer with a selective synthetic lethality mechanism. A mixed treatment by means of CDK-1 and PARP-1 inhibitors resulted in radical breast cancer cell growth reduction. Inhibitors with a dual target mechanism of action could arrest cancer progression by simultaneously blocking the DNA repair mechanism and cell cycle, resulting in advantageous monotherapy. To this aim, in the present work, we identified compound 645656 with a significant affinity for both CDK-1 and PARP-1 by a mixed ligand- and structure-based virtual screening protocol. The Biotarget Predictor Tool was used at first in a Multitarget mode to filter the large National Cancer Institute (NCI) database. Then, hierarchical docking studies were performed to further screen the compounds and evaluate the ligands binding mode, whose putative dual-target mechanism of action was investigated through the correlation between the antiproliferative activity data and the target proteins' (CDK-1 and PARP-1) expression pattern. Finally, a Molecular Dynamics Simulation confirmed the high stability of the most effective selected compound 645656 in complex with both PARP-1 and CDK-1.

Sex disparities in non-small cell lung cancer: mechanistic insights from a cRaf transgenic disease model

BACKGROUND

Women are at greater risk of developing non-small cell lung cancer (NSCLC), yet the underlying causes remain unclear.

METHODS

We performed whole genome scans in lung tumours of cRaf transgenic mice and identified miRNA, transcription factor and hormone receptor dependent gene regulations. We confirmed hormone receptors by immunohistochemistry and constructed regulatory gene networks by considering experimentally validated miRNA-gene and transcription factor-miRNA/gene targets. Bioinformatics, genomic foot-printing and gene enrichment analysis established sex-specific circuits of lung tumour growth. Translational research involved a large cohort of NSCLC patients. We evaluated commonalities in sex-specific NSCLC gene regulations between mice and humans and determined their prognostic value in Kaplan-Meier survival statistics and COX proportional hazard regression analysis.

FINDINGS

Overexpression of the cRaf kinase elicited an extraordinary 8-fold increase in tumour growth among females, and nearly 70% of the 112 differentially expressed genes (DEGs) were female specific. We identified oncogenes, oncomirs, tumour suppressors, cell cycle regulators and MAPK/EGFR signalling molecules, which prompted sex-based differences in NSCLC, and we deciphered a regulatory gene-network, which protected males from accelerated tumour growth. Strikingly, 41% of DEGs are targets of hormone receptors, and the majority (85%) are oestrogen receptor (ER) dependent. We confirmed the role of ER in a large cohort of NSCLC patients and validated 40% of DEGs induced by cRaf in clinical tumour samples.

INTERPRETATION

We report the molecular wiring that prompted sex disparities in tumour growth. This allowed us to propose the development of molecular targeted therapies by jointly blocking ER, CDK1 and arginase 2 in NSCLC.

FUNDING

We gratefully acknowledge the financial support of the Lower Saxony Ministry of Culture and Sciences and Volkswagen Foundation, Germany to JB (25A.5-7251-99-3/00) and of the Chinese Scholarship Council to SZ (202008080022). This publication is funded by the Deutsche Forschungsgemeinschaft (DFG) as part of the "Open Access Publikationskosten" program.

Targeting CDK1 in cancer: mechanisms and implications

Cyclin dependent kinases (CDKs) are serine/threonine kinases that are proposed as promising candidate targets for cancer treatment. These proteins complexed with cyclins play a critical role in cell cycle progression. Most CDKs demonstrate substantially higher expression in cancer tissues compared with normal tissues and, according to the TCGA database, correlate with survival rate in multiple cancer types. Deregulation of CDK1 has been shown to be closely associated with tumorigenesis. CDK1 activation plays a critical role in a wide range of cancer types; and CDK1 phosphorylation of its many substrates greatly influences their function in tumorigenesis. Enrichment of CDK1 interacting proteins with Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis was conducted to demonstrate that the associated proteins participate in multiple oncogenic pathways. This abundance of evidence clearly supports CDK1 as a promising target for cancer therapy. A number of small molecules targeting CDK1 or multiple CDKs have been developed and evaluated in preclinical studies. Notably, some of these small molecules have also been subjected to human clinical trials. This review evaluates the mechanisms and implications of targeting CDK1 in tumorigenesis and cancer therapy.

Paralog-based synthetic lethality: rationales and applications

Tumor cells can result from gene mutations and over-expression. Synthetic lethality (SL) offers a desirable setting where cancer cells bearing one mutated gene of an SL gene pair can be specifically targeted by disrupting the function of the other genes, while leaving wide-type normal cells unharmed. Paralogs, a set of homologous genes that have diverged from each other as a consequence of gene duplication, make the concept of SL feasible as the loss of one gene does not affect the cell's survival. Furthermore, homozygous loss of paralogs in tumor cells is more frequent than singletons, making them ideal SL targets. Although high-throughput CRISPR-Cas9 screenings have uncovered numerous paralog-based SL pairs, the unclear mechanisms of targeting these gene pairs and the difficulty in finding specific inhibitors that exclusively target a single but not both paralogs hinder further clinical development. Here, we review the potential mechanisms of paralog-based SL given their function and genetic combination, and discuss the challenge and application prospects of paralog-based SL in cancer therapeutic discovery.

PIN1 and CDK1 cooperatively govern pVHL stability and suppressive functions

The VHL protein (pVHL) functions as a tumor suppressor by regulating the degradation or activation of protein substrates such as HIF1α and Akt. In human cancers harboring wild-type VHL, the aberrant downregulation of pVHL is frequently detected and critically contributes to tumor progression. However, the underlying mechanism by which the stability of pVHL is deregulated in these cancers remains elusive. Here, we identify cyclin-dependent kinase 1 (CDK1) and peptidyl-prolyl cis-trans isomerase NIMA-interacting 1 (PIN1) as two previously uncharacterized regulators of pVHL in multiple types of human cancers harboring wild-type VHL including triple-negative breast cancer (TNBC). PIN1 and CDK1 cooperatively modulate the protein turnover of pVHL, thereby conferring tumor growth, chemotherapeutic resistance and metastasis both in vitro and in vivo. Mechanistically, CDK1 directly phosphorylates pVHL at Ser80, which primes the recognition of pVHL by PIN1. PIN1 then binds to phosphorylated pVHL and facilitates the recruitment of the E3 ligase WSB1, therefore targeting pVHL for ubiquitination and degradation. Furthermore, the genetic ablation or pharmacological inhibition of CDK1 by RO-3306 and PIN1 by all-trans retinoic acid (ATRA), the standard care for Acute Promyelocytic Leukemia could markedly suppress tumor growth, metastasis and sensitize cancer cells to chemotherapeutic drugs in a pVHL dependent manner. The histological analyses show that PIN1 and CDK1 are highly expressed in TNBC samples, which negatively correlate with the expression of pVHL. Taken together, our findings reveal the previous unrecognized tumor-promoting function of CDK1/PIN1 axis through destabilizing pVHL and provide the preclinical evidence that targeting CDK1/PIN1 is an appealing strategy in the treatment of multiple cancers with wild-type VHL.

A compendium of Androgen Receptor Variant 7 target genes and their role in Castration Resistant Prostate Cancer

Persistent androgen receptor (AR) signalling is the main driver of prostate cancer (PCa). Truncated isoforms of the AR called androgen receptor variants (AR-Vs) lacking the ligand binding domain often emerge during treatment resistance against AR pathway inhibitors such as Enzalutamide. This review discusses how AR-Vs drive a more aggressive form of PCa through the regulation of some of their target genes involved in oncogenic pathways, enabling disease progression. There is a pressing need for the development of a new generation of AR inhibitors which can repress the activity of both the full-length AR and AR-Vs, for which the knowledge of differentially expressed target genes will allow evaluation of inhibition efficacy. This review provides a detailed account of the most common variant, AR-V7, the AR-V7 regulated genes which have been experimentally validated, endeavours to understand their relevance in aggressive AR-V driven PCa and discusses the utility of the downstream protein products as potential drug targets for PCa treatment.

Cyclin-dependent kinases in cancer: Role, regulation, and therapeutic targeting

Regulated cell division is one of the fundamental phenomena which is the basis of all life on earth. Even a single base pair mutation in DNA leads to the production of the dysregulated protein that can have catastrophic consequences. Cell division is tightly controlled and orchestrated by proteins called cyclins and cyclin-dependent kinase (CDKs), which serve as licensing factors during different phases of cell division. Dysregulated cell division is one of the most important hallmarks of cancer and is commonly associated with a mutation in cyclins and CDKs along with tumor suppressor proteins. Therefore, targeting the component of the cell cycle which leads to these characteristics would be an effective strategy for treating cancers. Specifically, Cyclin-dependent kinases (CDKs) involved in cell cycle regulation have been identified to be overexpressed in many cancers. Many studies indicate that oncogenesis occurs in cancerous cells by the overactivity of different CDKs, which impact cell cycle progression and checkpoint dysregulation which is responsible for development of tumor. The development of CDK inhibitors has emerged as a promising and novel approach for cancer treatment in both solid and hematological malignancies. Some of the novel CDK inhibitors have shown remarkable results in clinical trials, such as-Ribociclib®, Palbociclib® and Abemaciclib®, which are CDK4/6 inhibitors and have received FDA approval for the treatment of breast cancer. In this chapter, we discuss the molecular mechanism through which cyclins and CDKs regulate cell cycle progression and the emergence of cyclins and CDKs as rational targets in cancer. We also discuss recent advances in developing CDK inhibitors, which have emerged as a novel class of inhibitors, and their associated toxicities in recent years.

USP14 regulates cell cycle progression through deubiquitinating CDK1 in breast cancer

Abnormal proliferation and cell cycle perturbation are the main hallmarks of breast cancer. Cyclin-dependent kinase 1 (CDK1) is one of the key kinases for cell transition from the G2 phase to M phase during the cell cycle progression. However, little is known about the degradation mechanisms of CDK1. USP14 (ubiquitin-specific processing protease 14) is an important proteasome-associated deubiquitinase that is critical for proteome homeostasis and plays a crucial role in the initiation and development of cancer. In this study, we find that USP14 shows high expression in breast cancer cells and results in the abnormal proliferation of cancer cells. Furthermore, we examine cell cycle distribution by flow cytometry and find that inhibition of USP14 causes cell cycle arrest in G2/M phase. As CDK1 is the key kinase in G2/M phase, we detect the interaction between USP14 and CDK1 and the effect of USP14 on the deubiquitination of CDK1. The results reveal that USP14 interacts with CDK1 and stabilizes CDK1 by deubiquitinating K48-linked ubiquitination. In conclusion, our findings reveal an indispensable role of USP14 in regulating cell cycle progression by stabilizing CDK1 in breast cancer, suggesting that USP14 may be used as a potential therapeutic target in breast cancer therapy.

Stabilization of c-Myc by the atypical cell cycle regulator, Spy1, decreases efficacy of breast cancer treatments

PURPOSE

c-Myc is frequently upregulated in breast cancers, however, targeting c-Myc has proven to be a challenge. Targeting of downstream mediators of c-Myc, such as the 'cyclin-like' cell cycle regulator Spy1, may be a viable therapeutic option in a subset of breast cancer subtypes.

METHODS

Mouse mammary tumor cells isolated from MMTV-Myc mice and human breast cancer cell lines were used to manipulate Spy1 levels followed by tamoxifen or chemotherapeutic treatment with a variety of endpoints. Patient samples from TNBC patients were obtained and constructed into a TMA and stained for c-Myc and Spy1 protein levels.

RESULTS

Over time, MMTV-Myc cells show a decreased response to tamoxifen treatment with increasing levels of Spy1 in the tamoxifen-resistant cells. shRNA against Spy1 re-establishes tamoxifen sensitivity. Spy1 was found to be highly elevated in human TNBC cell and patient samples, correlating to c-Myc protein levels. c-Myc was found to be stabilized by Spy1 and knocking down Spy1 in TNBC cells shows a significant increase in response to chemotherapy treatments.

CONCLUSION

Understanding the interplay between protein expression level and response to treatment is a critical factor in developing novel treatment options for breast cancer patients. These data have shown a connection between Spy1 and c-Myc protein levels in more aggressive breast cancer cells and patient samples. Furthermore, targeting c-Myc has proven difficult, these data suggest targeting Spy1 even when c-Myc is elevated can confer an advantage to current chemotherapies.

A novel age-related gene expression signature associates with proliferation and disease progression in breast cancer

BACKGROUND AND OBJECTIVE

Breast cancer (BC) diagnosed at ages <40 years presents with more aggressive tumour phenotypes and poorer clinical outcome compared to older BC patients. Here, we explored transcriptional BC alterations to gain a better understanding of age-related tumour biology, also subtype-stratified.

METHODS

We studied publicly available global BC mRNA expression (n = 3999) and proteomics data (n = 113), exploring differentially expressed genes, enriched gene sets, and gene networks in the young compared to older patients.

RESULTS

We identified transcriptional patterns reflecting increased proliferation and oncogenic signalling in BC of the young, also in subtype-stratified analyses. Six up-regulated hub genes built a novel age-related score, significantly associated with aggressive clinicopathologic features. A high 6 Gene Proliferation Score (6GPS) demonstrated independent prognostic value when adjusted for traditional clinicopathologic variables and the molecular subtypes. The 6GPS significantly associated also with disease-specific survival within the luminal, lymph node-negative and Oncotype Dx intermediate subset.

CONCLUSIONS

We here demonstrate evidence of higher tumour cell proliferation in young BC patients, also when adjusting for molecular subtypes, and identified a novel age-based six-gene signature pointing to aggressive tumour features, tumour proliferation, and reduced survival-also in patient subsets with expected good prognosis.

Palbociclib Induces the Apoptosis of Lung Squamous Cell Carcinoma Cells via RB-Independent STAT3 Phosphorylation

Lung squamous cell carcinoma (LUSC) treatment response is poor and treatment alternatives are limited. Palbociclib, a cyclin-dependent kinase (CDK) 4/6 inhibitor, has recently been approved for hormone receptor-positive breast cancer patients and applied in multiple preclinical models, but its use for LUSC therapy remains elusive. Here, we investigated whether palbociclib induced cell apoptosis and dissected the underlying mechanism in LUSC. We found that palbociclib induced LUSC cell apoptosis through inhibition of Src tyrosine kinase/signal transducers and activators of transcription 3 (STAT3). Interestingly, palbociclib reduced STAT3 signaling in LUSC cells interfered by retinoblastoma tumor-suppressor gene (RB), suggesting that pro-apoptosis effect of palbociclib was independent of classic CDK4/6-RB signaling. Furthermore, palbociclib could suppress IL-1β and IL-6 expression, and therefore blocked Src/STAT3 signaling, which were rescued by either recombinant human IL-1β or IL-6. Moreover, Myc mediated the sensitivity of LUSC cells to palbociclib. Our discoveries demonstrated that palbociclib induces apoptosis of LUSC cells through the Src/STAT3 axis in an RB-independent manner, and provided a reliable experimental basis of clinical studies in LUSC patients.

Discovering gene regulatory networks of multiple phenotypic groups using dynamic Bayesian networks

Dynamic Bayesian networks (DBNs) can be used for the discovery of gene regulatory networks (GRNs) from time series gene expression data. Here, we suggest a strategy for learning DBNs from gene expression data by employing a Bayesian approach that is scalable to large networks and is targeted at learning models with high predictive accuracy. Our framework can be used to learn DBNs for multiple groups of samples and highlight differences and similarities in their GRNs. We learn these DBN models based on different structural and parametric assumptions and select the optimal model based on the cross-validated predictive accuracy. We show in simulation studies that our approach is better equipped to prevent overfitting than techniques used in previous studies. We applied the proposed DBN-based approach to two time series transcriptomic datasets from the Gene Expression Omnibus database, each comprising data from distinct phenotypic groups of the same tissue type. In the first case, we used DBNs to characterize responders and non-responders to anti-cancer therapy. In the second case, we compared normal to tumor cells of colorectal tissue. The classification accuracy reached by the DBN-based classifier for both datasets was higher than reported previously. For the colorectal cancer dataset, our analysis suggested that GRNs for cancer and normal tissues have a lot of differences, which are most pronounced in the neighborhoods of oncogenes and known cancer tissue markers. The identified differences in gene networks of cancer and normal cells may be used for the discovery of targeted therapies.

Dinaciclib inhibits the stemness of two subtypes of human breast cancer cells by targeting the FoxM1 and Hedgehog signaling pathway

Cyclin‑dependent kinase (CDK)4/6 inhibitors in combination with endocrine therapy are the current standard of care used in the first‑line treatment of hormone receptor‑positive/HER2‑negative metastatic breast cancer (BC). Although CDK4/6 inhibitors mainly target the cell cycle, emerging evidence has indicated further potential roles of CDKs other than regulating cell cycle progression. The G₁ and G₂/M transition regulators, including cyclins D and E, as well as their catalytic partners, CDK2, CDK4 and CDK6, have been reported to play crucial roles in pluripotency maintenance and cell fate decisions of human pluripotent stem cells by controlling transcription factors, signaling pathways and epigenetic regulators. Dinaciclib, a CDK1/2/5/9 inhibitor, is currently being evaluated in clinical trials against various cancer types, including BC. However, the underlying molecular mechanisms of CDK1/2/5/9 inhibitors in regulating BC stemness remain poorly understood. The present study aimed to examine the stemness‑inhibitory effects of dinaciclib in MCF‑7 (luminal) and HCC‑1806 (triple‑negative) BC cells. We found that this drug not only effectively reduced the self‑renewal abilities and other malignant properties, but also dose‑dependently decreased the protein expression levels of three BC stem cell markers, CD44, aldehyde dehydrogenase 1 family member A1 (ALDH1A1) and BMI1 proto‑oncogene, polycomb ring finger (Bmi1), as well as three embryonic stem cell markers, Oct4, Nanog and Sox2. Moreover, the dinaciclib‑induced decrease of Oct4 and Nanog protein expression was able to be restored by co‑treatment with MG‑132, a proteasome inhibitor. Forkhead box M1 (FoxM1), both a stemness‑stimulating transcription factor and a cell cycle regulator, along with the Hedgehog signaling pathway, were identified as the therapeutic targets of dinaciclib. Collectively, the present results demonstrated a novel role of dinaciclib in suppressing BC stemness and indicated its potential use for future cancer treatments.

A Phase Ib/II Study of the CDK4/6 Inhibitor Ribociclib in Combination with Docetaxel plus Prednisone in Metastatic Castration-Resistant Prostate Cancer

PURPOSE

Ribociclib, a CDK4/6 inhibitor, demonstrates preclinical antitumor activity in combination with taxanes. We evaluated the safety and efficacy of ribociclib plus docetaxel in a phase Ib/II study in metastatic castration-resistant prostate cancer (mCRPC).

PATIENTS AND METHODS

Patients had chemotherapy-naïve mCRPC with progression on ≥ 1 androgen receptor signaling inhibitor (ARSI). The phase II primary endpoint was 6-month radiographic progression-free survival (rPFS) rate, with an alternative hypothesis of 55% versus 35% historical control. Circulating tumor cells (CTC) were collected at baseline and genomically profiled.

RESULT

Forty-three patients were enrolled (N = 30 in phase II). Two dose-limiting toxicities were observed (grade 4 neutropenia and febrile neutropenia). The recommended phase II dose (RP2D) and schedule was docetaxel 60 mg/m2 every 21 days plus ribociclib 400 mg/day on days 1-4 and 8-15 with filgrastim on days 5-7. At the RP2D, neutropenia was the most common grade ≥ 3 adverse event (37%); however, no cases of febrile neutropenia were observed. The primary endpoint was met; the 6-month rPFS rate was 65.8% [95% confidence interval (CI): 50.6%-85.5%; P = 0.005] and median rPFS was 8.1 months (95% CI, 6.0-10.0 months). Thirty-two percent of evaluable patients achieved a PSA50 response. Nonamplified MYC in baseline CTCs was associated with longer rPFS (P = 0.052).

CONCLUSIONS

The combination of intermittent ribociclib plus every-3-weeks docetaxel demonstrated acceptable toxicity and encouraging efficacy in ARSI-pretreated mCRPC. Genomic profiling of CTCs may enrich for those most likely to derive benefit. Further evaluation in a randomized clinical trial is warranted.

Cyclin-Dependent Kinase Synthetic Lethality Partners in DNA Damage Response

Cyclin-dependent kinases (CDKs) are pivotal mediators and effectors of the DNA damage response (DDR) that regulate both the pathway components and proteins involved in repair processes. Synthetic lethality (SL) describes a situation in which two genes are linked in such a way that the lack of functioning of just one maintains cell viability, while depletion of both triggers cell death. Synthetic lethal interactions involving CDKs are now emerging, and this can be used to selectively target tumor cells with DNA repair defects. In this review, SL interactions of CDKs with protooncogene products MYC, poly (ADP-ribose) polymerase (PARP-1), and cellular tumor antigen p53 (TP53) are discussed. The individual roles of each of the SL partners in DDR are described.

MYCMI-7: A Small MYC-Binding Compound that Inhibits MYC: MAX Interaction and Tumor Growth in a MYC-Dependent Manner

Deregulated expression of MYC family oncogenes occurs frequently in human cancer and is often associated with aggressive disease and poor prognosis. While MYC is a highly warranted target, it has been considered "undruggable," and no specific anti-MYC drugs are available in the clinic. We recently identified molecules named MYCMIs that inhibit the interaction between MYC and its essential partner MAX. Here we show that one of these molecules, MYCMI-7, efficiently and selectively inhibits MYC:MAX and MYCN:MAX interactions in cells, binds directly to recombinant MYC, and reduces MYC-driven transcription. In addition, MYCMI-7 induces degradation of MYC and MYCN proteins. MYCMI-7 potently induces growth arrest/apoptosis in tumor cells in a MYC/MYCN-dependent manner and downregulates the MYC pathway on a global level as determined by RNA sequencing. Sensitivity to MYCMI-7 correlates with MYC expression in a panel of 60 tumor cell lines and MYCMI-7 shows high efficacy toward a collection of patient-derived primary glioblastoma and acute myeloid leukemia (AML) ex vivo cultures. Importantly, a variety of normal cells become G₁ arrested without signs of apoptosis upon MYCMI-7 treatment. Finally, in mouse tumor models of MYC-driven AML, breast cancer, and MYCN-amplified neuroblastoma, treatment with MYCMI-7 downregulates MYC/MYCN, inhibits tumor growth, and prolongs survival through apoptosis with few side effects. In conclusion, MYCMI-7 is a potent and selective MYC inhibitor that is highly relevant for the development into clinically useful drugs for the treatment of MYC-driven cancer.

SIGNIFICANCE

Our findings demonstrate that the small-molecule MYCMI-7 binds MYC and inhibits interaction between MYC and MAX, thereby hampering MYC-driven tumor cell growth in culture and in vivo while sparing normal cells.

MYCMI-7: A Small MYC-Binding Compound that Inhibits MYC: MAX Interaction and Tumor Growth in a MYC-Dependent Manner

Deregulated expression of MYC family oncogenes occurs frequently in human cancer and is often associated with aggressive disease and poor prognosis. While MYC is a highly warranted target, it has been considered "undruggable," and no specific anti-MYC drugs are available in the clinic. We recently identified molecules named MYCMIs that inhibit the interaction between MYC and its essential partner MAX. Here we show that one of these molecules, MYCMI-7, efficiently and selectively inhibits MYC:MAX and MYCN:MAX interactions in cells, binds directly to recombinant MYC, and reduces MYC-driven transcription. In addition, MYCMI-7 induces degradation of MYC and MYCN proteins. MYCMI-7 potently induces growth arrest/apoptosis in tumor cells in a MYC/MYCN-dependent manner and downregulates the MYC pathway on a global level as determined by RNA sequencing. Sensitivity to MYCMI-7 correlates with MYC expression in a panel of 60 tumor cell lines and MYCMI-7 shows high efficacy toward a collection of patient-derived primary glioblastoma and acute myeloid leukemia (AML) ex vivo cultures. Importantly, a variety of normal cells become G₁ arrested without signs of apoptosis upon MYCMI-7 treatment. Finally, in mouse tumor models of MYC-driven AML, breast cancer, and MYCN-amplified neuroblastoma, treatment with MYCMI-7 downregulates MYC/MYCN, inhibits tumor growth, and prolongs survival through apoptosis with few side effects. In conclusion, MYCMI-7 is a potent and selective MYC inhibitor that is highly relevant for the development into clinically useful drugs for the treatment of MYC-driven cancer.

Significance

Our findings demonstrate that the small-molecule MYCMI-7 binds MYC and inhibits interaction between MYC and MAX, thereby hampering MYC-driven tumor cell growth in culture and in vivo while sparing normal cells.

CRIF1-CDK2 Interface Inhibitors Enhance Taxol Inhibition of the Lethal Triple-Negative Breast Cancer

Simple Summary

This study reported our most recent results for targeting triple-negative breast cancer (TNBC) with a low survival rate, using CR6-interacting factor 1–cyclin-dependent kinase 2 (CRIF1–CDK2) interface inhibitors, by inhibiting the resistance to taxol treatment. Presently, over 50% of TNBC patients become resistant to chemotherapy and, to date, no solution is available. The combined treatment, using CRIF1–CDK2 interface inhibitors with chemotherapy, provides an unprecedented strategy against the deadly TNBC.

Abstract

Paclitaxel (taxol), a chemotherapeutic agent, remains the standard of care for the lethal triple-negative breast cancer (TNBC). However, over 50% of TNBC patients become resistant to chemotherapy and, to date, no solution is available. CR6-interacting factor 1 (CRIF1) is reported to act as a negative regulator of the cell cycle by interacting with cyclin-dependent kinase 2 (CDK2). In our study, two selective CRIF1–CDK2 interface inhibitors were used to investigate whether they could exert anti-proliferative activity on the TNBC cell lines. When combined with taxol treatment, these two inhibitors can advance the cells from G0/G1 to S and G2/M phases, producing irreparable damage to the cells, which then undergo apoptosis. Moreover, they enhanced the reduction in cell proliferation induced by taxol in TNBC cells, thereby improving sensitivity to taxol in these cell lines. Importantly, the inhibitors did not regulate the cell cycle in normal cells, indicating their high selectivity towards TNBC cells. Overall, the resistance to the anti-proliferative effects induced by taxol can be significantly reduced by the combined treatment with selective CRIF1–CDK2 interface inhibitors, making a conceptual advance in the CDK-related cancer treatment.

The Renaissance of Cyclin Dependent Kinase Inhibitors

Cyclin-dependent kinases (CDK) regulate cell cycle progression. During tumor development, altered expression and availability of CDKs strongly contribute to impaired cell proliferation, a hallmark of cancer. In recent years, targeted inhibition of CDKs has shown considerable therapeutic benefit in a variety of tumor entities. Their success is reflected in clinical approvals of specific CDK4/6 inhibitors for breast cancer. This review provides a detailed insight into the molecular mechanisms of CDKs as well as a general overview of CDK inhibition. It also summarizes the latest research approaches and current advances in the treatment of head and neck cancer with CDK inhibitors. Instead of monotherapies, combination therapies with CDK inhibitors may especially provide promising results in tumor therapy. Indeed, recent studies have shown a synergistic effect of CDK inhibition together with chemo- and radio- and immunotherapy in cancer treatment to overcome tumor evasion, which may lead to a renaissance of CDK inhibitors.

Japanese Encephalitis Virus NS1' Protein Interacts with Host CDK1 Protein to Regulate Antiviral Response

Type I interferon (IFN-I) is a key component of the host innate immune system. To establish efficient replication, viruses have developed several strategies to escape from the host IFN response. Japanese encephalitis virus (JEV) NS1', a larger NS1-related protein, is known to inhibit the mitochondrial antiviral signaling (MAVS)-mediated IFN-β induction by increasing the binding of transcription factors (CREB and c-Rel) to the microRNA 22 (miRNA-22) promoter. However, the mechanism by which NS1' induces the recruitment of CREB and c-Rel onto the miRNA-22 promoter is unknown. Here, we found that JEV NS1' protein interacts with the host cyclin-dependent kinase 1 (CDK1) protein. Mechanistically, NS1' interrupts the CDC25C phosphatase-mediated dephosphorylation of CDK1, which prolongs the phosphorylation status of CDK1 and leads to the inhibition of MAVS-mediated IFN-β induction. Furthermore, the CREB phosphorylation and c-Rel activation through the IκBα phosphorylation were observed to be enhanced upon the augmentation of CDK1 phosphorylation by NS1'. The abrogation of CDK1 activity by a small-molecule inhibitor significantly suppressed the JEV replication in vitro and in vivo. Moreover, the administration of CDK1 inhibitor protected the wild-type mice from JEV-induced lethality but showed no effect on the MAVS^-/- mice challenged with JEV. In conclusion, our study provides new insight into the mechanism of JEV immune evasion, which may lead to the development of novel therapeutic options to treat JEV infection. IMPORTANCE Japanese encephalitis virus (JEV) is the main cause of acute human encephalitis in Asia. The unavailability of specific treatment for Japanese encephalitis demands a better understanding of the basic cellular mechanisms that contribute to the onset of disease. The present study identifies a novel interaction between the JEV NS1' protein and the cellular CDK1 protein, which facilitates the JEV replication by dampening the cellular antiviral response. This study sheds light on a novel mechanism of JEV replication, and thus our findings could be employed for developing new therapies against JEV infection.

Cyclin-dependent kinases-based synthetic lethality: Evidence, concept, and strategy

Synthetic lethality is a proven effective antitumor strategy that has attracted great attention. Large-scale screening has revealed many synthetic lethal genetic phenotypes, and relevant small-molecule drugs have also been implemented in clinical practice. Increasing evidence suggests that CDKs, constituting a kinase family predominantly involved in cell cycle control, are synthetic lethal factors when combined with certain oncogenes, such as MYC, TP53, and RAS, which facilitate numerous antitumor treatment options based on CDK-related synthetic lethality. In this review, we focus on the synthetic lethal phenotype and mechanism related to CDKs and summarize the preclinical and clinical discoveries of CDK inhibitors to explore the prospect of CDK inhibitors as antitumor compounds for strategic synthesis lethality in the future.

Phosphoproteomics Identifies Significant Biomarkers Associated with the Proliferation and Metastasis of Prostate Cancer

The spider peptide toxins HNTX-III and JZTX-I are a specific inhibitor and activator of TTX-S VGSCs, respectively. They play important roles in regulating MAT-LyLu cell metastasis in prostate cancer. In order to identify key biomarkers involved in the regulation of MAT-LyLu cell metastasis, iTRAQ-based quantitative phosphoproteomics analysis was performed on cells treated with HNTX-III, JZTX-I and blank. A total of 554 unique phosphorylated proteins and 1779 distinct phosphorylated proteins were identified, while 55 and 36 phosphorylated proteins were identified as differentially expressed proteins in HNTX-III and JZTX-I treated groups compared with control groups. Multiple bioinformatics analysis based on quantitative phosphoproteomics data suggested that the differentially expressed phosphorylated proteins and peptides were significantly associated with the migration and invasion of prostate tumors. Specifically, the toxins HNTX-III and JZTX-I have opposite effects on tumor formation and metastasis by regulating the expression and phosphorylation level of causal proteins. Herein, we highlighted three key proteins EEF2, U2AF2 and FLNC which were down-regulated in HNTX-III treated cells and up-regulated in JZTX-I treated cells. They played significant roles in cancer related physiological and pathological processes. The differentially expressed phosphorylated proteins identified in this study may serve as potential biomarkers for precision medicine for prostate cancer in the near future.

Peptide-tiling screens of cancer drivers reveal oncogenic protein domains and associated peptide inhibitors

Gene fragments derived from structural domains mediating physical interactions can modulate biological functions. Utilizing this, we developed lentiviral overexpression libraries of peptides comprehensively tiling high-confidence cancer driver genes. Toward inhibiting cancer growth, we assayed ~66,000 peptides, tiling 65 cancer drivers and 579 mutant alleles. Pooled fitness screens in two breast cancer cell lines revealed peptides, which selectively reduced cellular proliferation, implicating oncogenic protein domains important for cell fitness. Coupling of cell-penetrating motifs to these peptides enabled drug-like function, with peptides derived from EGFR and RAF1 inhibiting cell growth at IC50s of 27-63 μM. We anticipate that this peptide-tiling (PepTile) approach will enable rapid de novo mapping of bioactive protein domains and associated interfering peptides.

A tipping-point for apoptosis following dual inhibition of HER2 signaling network by T-DM1 plus GDC-0980 maximizes anti-tumor efficacy

HER2 signaling network and its complex relationship with the PI3K-AKT-mTOR pathway explain the acquired resistance to anti-HER2 therapy observed in clinics. Such complexity has been clinically evident from the limited efficacy of data in the BOLERO-1 and BOLERO-3 trials, which tested combinations of trastuzumab (T), everolimus, and chemotherapy in women with HER2+ advanced BC. In the following MARIANNE trial also, a combination of T-DM1 plus pertuzumab delivered a non-inferior but yet not superior PFS compared to trastuzumab plus a taxane. Algorithmic inhibition of PI3K/mTOR along with T or T-DM1 is, therefore, an attractive drug combination, and we tested the combination(s) in HER2+ BC, especially in T-resistant and PIK3CA mutated conditions. GDC-0980, a dual pan-PI3K/mTOR inhibitor alone or in combination with T or T-DM1, was examined in a panel of HER2+ T-sensitive (BT474, SKBR3), HER2+ T-resistant (BT474HerR), HER2+/PIK3CA mutant (HCC1954, MDA-MB453), and HER2+/PTEN mutant (HCC1569) BC cell lines. GDC-0980 re-sensitized trastuzumab-resistant, PIK3CA mutant, or PTEN mutant cells to T and acted additively with T. Importantly, this activity was more when GDC-0980 is combined with T-DM1. The combination (with T or with T-DM1) was then tested in the HER2+/T-sensitive, HER2+/T-resistant, and HER2+/PIK3CA mutated BC xenograft models for the anti-tumor effect. Along with its anti-tumor effect, GDC-0980 effectively decreased tumor angiogenesis (CD31 staining). Maximum anti-tumor (from tumor growth inhibition to tumor regression) efficiency was observed in all three xenograft models when T-DM1 was combined with GDC-0980. The anti-proliferative effects of GDC-0980 as evidenced by a decreased p-AKT (Ser473, The308), p-P70S6K, p-S6RP, and p-4EBP1, along with blockade of clonogenic 3D growth was accompanied by the initiation of apoptotic activity (annexin V, CASPASE3, cleaved PARP1 and mitochondrial depolarization); and was significantly superior when GDC-0980 combined with T-DM1. Interestingly, both trastuzumab and T-DM1 induce PD-L1 expression in HER2 amplified BC cells. Our data provide evidence that an oncogenic mutation of PIK3CA and HER2-amplification may represent biomarkers to identify patients who may benefit most from the use of GDC-0980 and an opportunity to include immunotherapy in the combination of anti-HER2 therapy.

Targeting cell-cycle machinery in cancer

Abnormal activity of the core cell-cycle machinery is seen in essentially all tumor types and represents a driving force of tumorigenesis. Recent studies revealed that cell-cycle proteins regulate a wide range of cellular functions, in addition to promoting cell division. With the clinical success of CDK4/6 inhibitors, it is becoming increasingly clear that targeting individual cell-cycle components may represent an effective anti-cancer strategy. Here, we discuss the potential of inhibiting different cell-cycle proteins for cancer therapy.

Age-Associated Proteomic Signatures and Potential Clinically Actionable Targets of Colorectal Cancer

The occurrence and prevalence of colorectal cancer (CRC) is closely associated with age. More than 90% of patients with CRC are diagnosed after 50 years of age. However, CRC incidence of young individuals has been increasing since 1990s, whereas the overall CRC frequency is declining. Distinct overall survival rates between young and aged patients with CRC have been established. Tremendous efforts have been made to clarify the underlying mechanisms of age-dependent clinical differences, but it still remains elusive. Here, we performed proteomic profiling of 50 patients with CRC and revealed proteomic signatures of CRC across age groups. Gene set enrichment analysis showed that distinct age-dependent clinical outcomes might mainly attribute to varied MYC targets V1/V2, E2F targets and G2M checkpoint gene sets, which were associated with cancer cell proliferation, cell apoptosis, tumor growth, and tumor metastasis. Multiple linear regression analysis revealed a large number of functional proteins, such as NOP2, CSE1L, NHP2, NOC2L and CDK1, with adjusted expression significantly correlated with age (p < 0.05). Among them, NHP2 is a core component of the telomerase complex associated with age. High NHP2 expression predicted poor overall survival, with a more significant correlation in aged patients with CRC. Knockdown of NHP2 significantly suppressed cancer cell proliferation. In addition, we revealed some age-related potential clinically actionable targets, such as PSEN1, TSPO, and CDK1, which might be more suitable for patients with late-onset CRC. Collectively, this study identifies age-associated proteomic signatures and potential therapeutic targets of CRC and may help make a precise decision on CRC treatment.

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The proteomic signatures of early-onset CRC are disclosed.

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Alterations of some proteins between cancerous and normal tissues are age-correlated.

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NHP2, overexpressed in tumors especially in aged patients, predicts poor prognosis.

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Potential age-dependent druggable targets and their inhibitors are summarized.

CDK1 in Breast Cancer: Implications for Theranostic Potential

Breast cancer has been identified as one of the main cancer-related deaths among women during some last decades. Recent advances in the introduction of novel potent anti-cancer therapeutics in association with early detection methods led to a decrease in the mortality rate of breast cancer. However, the scenario of breast cancer is yet going on and further improvements in the current anti-cancer therapeutic approaches are needed. Several factors are present in the tumor microenvironment which help to cancer progression and suppression of anti-tumor responses. Targeting these cancer-promoting factors in the tumor microenvironment has been suggested as a potent immunotherapeutic approach for cancer therapy. Among the various tumorsupporting factors, Cyclin-Dependent Kinases (CDKs) are proposed as a novel promising target for cancer therapy. These factors in association with cyclins play a key role in cell cycle progression. Dysregulation of CDKs which leads to increased cell proliferation has been identified in various cancers, such as breast cancer. Accordingly, the development and use of CDK-inhibitors have been associated with encouraging results in the treatment of breast cancer. However, it is unknown that the inhibition of which CDK is the most effective strategy for breast cancer therapy. Since the selective blockage of CDK1 alone or in combination with other therapeutics has been associated with potent anti-cancer outcomes, it is suggested that CDK1 may be considered as the best CDK target for breast cancer therapy. In this review, we will discuss the role of CDK1 in breast cancer progression and treatment.

Laryngeal squamous cell carcinoma cell lines show high tolerance for siRNA-mediated CDK1 knockdown

Alterations of the cell cycle checkpoints lead to uncontrolled cell growth and result in tumorigenesis. One of the genes essential for cell proliferation and cell cycle regulation is CDK1. This makes it a potential target in cancer therapy. In our previous study we have shown upregulation of this gene in laryngeal squamous cell carcinoma (LSCC). Here we analyze the impact of siRNA-mediated CDK1 knockdown on cell proliferation and viability, measured with cell growth monitoring and colorimetric test (CCK8 assay), respectively. We proved that a reduction of CDK1 expression by more than 50% has no effect on these cellular processes in LSCC cell lines (n=2). Moreover, using microarrays, we analyzed global gene expression deregulation in these cell lines after CDK1 knockdown. We searched for enriched ontologies in the group of identified 137 differentially expressed genes (>2-fold change). Within this group we found 3 enriched pathways: protein binding (GO:0005515), mitotic nuclear division (GO:0007067) and transmembrane receptor protein tyrosine kinase signaling pathway (GO:0007169) and a group of 11 genes encoding proteins for which interaction with CDK1 was indicated with the use of bioinformatic tools. Among these genes we propose three: CDK6, CALD1 and FYN as potentially dependent on CDK1.

Synthesis and evaluation of novel thiosemicarbazone and semicarbazone analogs with both anti-proliferative and anti-metastatic activities against triple negative breast cancer

Triple-negative breast cancer (TNBC) is one of the most aggressive cancer with high mortality and recurrence rates. Hecogenin, a steroidal sapogenin, is reported as a potential anti-tumor agent against breast cancer. However, the moderate activity limits its further application in clinical. With the aim to identify novel analogues that are especially efficacious in therapy of TNBC, a series of novel hecogenin thiosemicarbazone and semicarbazone derivatives were designed, synthesized and biologically evaluated. Screening of cytotoxicity revealed that 4c could potently inhibit the proliferation of breast cancer cells (MCF-7 and MDA-MB-231 cells), lung cancer cells (A549) and colon cancer cells (HT-29) at low μM level. Importantly, further mechanism studies indicated the ability of 4c in inducing apoptosis of MDA-MB-231 cells by arresting the cell cycle. Moreover, 4c notably suppressed the migration and invasion of MDA-MB-231 cells compared to its parent hecogenin at the equal concentration.

miR-34c-3p targets CDK1 a synthetic lethality partner of KRAS in non-small cell lung cancer

Lung cancer is still the leading cause of death by cancer worldwide despite advances both in its detection and therapy. Multiple oncogenic driver alterations have been discovered, opening the prospective for new potential therapeutic targets. Among them, KRAS mutations represent the most frequent oncogene aberrations in non-small cell lung cancer (NSCLC) patients with a negative prognostic impact, but effective therapies targeting KRAS are not well characterized yet. Here, we demonstrate that the microRNA miR-34c-3p is a positive prognostic factor in KRAS-mutated NSCLC patients. Firstly, looking at the TGCA dataset, we found that high miR-34c-3p expression correlated with longer survival of KRAS-mutated NSCLC patients. In vitro assays on immortalized and patient-derived primary NSCLC cells revealed that miR-34c-3p overexpression increased apoptosis and lowered proliferation rate in KRASmut cells. Computational analysis and in vitro assays identified CDK1, one of the most promising lethal targets for KRAS-mutant cancer, as a target of miR-34c-3p. Moreover, the combination of CDK1 inhibition (mediated by RO3306) and miR-34c-3p overexpression resulted in an additive effect on the viability of KRASmut-expressing cells. Altogether, our findings demonstrate that miR-34c-3p is a novel biomarker that may allow tailored treatment for KRAS-mutated NSCLC patients.

Alternative approaches to target Myc for cancer treatment

The Myc proto-oncogene family consists of three members, C-MYC, MYCN, and MYCL, which encodes the transcription factor c-Myc (hereafter Myc), N-Myc, and L-Myc, respectively. Myc protein orchestrates diverse physiological processes, including cell proliferation, differentiation, survival, and apoptosis. Myc modulates about 15% of the global transcriptome, and its deregulation rewires the cellular signaling modules inside tumor cells, thereby acquiring selective advantages. The deregulation of Myc occurs in >70% of human cancers, and is related to poor prognosis; hence, hyperactivated Myc oncoprotein has been proposed as an ideal drug target for decades. Nevertheless, no specific drug is currently available to directly target Myc, mainly because of its "undruggable" properties: lack of enzymatic pocket for conventional small molecules to bind; inaccessibility for antibody due to the predominant nucleus localization of Myc. Although the topic of targeting Myc has actively been reviewed in the past decades, exciting new progresses in this field keep emerging. In this review, after a comprehensive summarization of valuable sources for potential druggable targets of Myc-driven cancer, we also peer into the promising future of utilizing macropinocytosis to deliver peptides like Omomyc or antibody agents to intracellular compartment for cancer treatment.

CDK1 serves as a novel therapeutic target for endometrioid endometrial cancer

Background: Endometrial cancer (EC) is one of the most common and prevalent gynecologic malignancies worldwide. The aim of this study was to identify a novel therapeutic target for endometrioid endometrial cancer.

Materials and Methods: Bioinformatic analysis was performed and CDK1 was screen out as one of the hub genes in the pathogenesis of EC. Immunohistochemistry was used to verify the expression of CDK1 in endometrial cancer tissue. Cell viability and colony formation were used to study the effects of CDK1 on the proliferation and colony formation of endometrial cancer cells in vitro. Apoptosis and cell cycle assays were used to elucidate the mechanism of CDK1 affecting cell proliferation. Tumor xenograft transplantation assay was performed to show the effects of CDK1 on the growth of endometrial cancer cells in vivo.

Results: CDK1 was over expressed in endometrioid endometrial cancer, and accumulation of cytoplasmic CDK1 was associated with histological grade of EC. CDK1 promoted endometrial cancer cell growth and colony formation in vitro. The inhibition of CDK1 activity induced cell apoptosis and caused G2/M phase arrest of cell cycle in endometrial cancer cells. The inhibition of CDK1 activity also inhibited endometrial cancer growth in xenograft models.

Conclusion: CDK1 was involved in the pathogenesis of endometrioid endometrial cancer and provided a novel therapeutic target for endometrioid endometrial cancer.

A Network Pharmacology Study on the Molecular Mechanisms of FDY003 for Breast Cancer Treatment

Herbal medicines have drawn considerable attention with regard to their potential applications in breast cancer (BC) treatment, a frequently diagnosed malignant disease, considering their anticancer efficacy with relatively less adverse effects. However, their mechanisms of systemic action have not been understood comprehensively. Based on network pharmacology approaches, we attempted to unveil the mechanisms of FDY003, an herbal drug comprised of Lonicera japonica Thunberg, Artemisia capillaris Thunberg, and Cordyceps militaris, against BC at a systemic level. We found that FDY003 exhibited pharmacological effects on human BC cells. Subsequently, detailed data regarding the biochemical components contained in FDY003 were obtained from comprehensive herbal medicine-related databases, including TCMSP and CancerHSP. By evaluating their pharmacokinetic properties, 18 chemical compounds in FDY003 were shown to be potentially active constituents interacting with 140 BC-associated therapeutic targets to produce the pharmacological activity. Gene ontology enrichment analysis using g:Profiler indicated that the FDY003 targets were involved in the modulation of cellular processes, involving the cell proliferation, cell cycle process, and cell apoptosis. Based on a KEGG pathway enrichment analysis, we further revealed that a variety of oncogenic pathways that play key roles in the pathology of BC were significantly enriched with the therapeutic targets of FDY003; these included PI3K-Akt, MAPK, focal adhesion, FoxO, TNF, and estrogen signaling pathways. Here, we present a network-perspective of the molecular mechanisms via which herbal drugs treat BC.

Protein co-expression networks identified from HOT lesions of ER+HER2-Ki-67high luminal breast carcinomas

Patients with estrogen receptor-positive/human epidermal growth factor receptor 2-negative/Ki-67-high (ER+HER2-Ki-67high) luminal breast cancer have a worse prognosis and do not respond to hormonal treatment and chemotherapy. This study sought to identify disease-related protein networks significantly associated with this subtype, by assessing in-depth proteomes of 10 lesions of high and low Ki-67 values (HOT, five; COLD, five) microdissected from the five tumors. Weighted correlation network analysis screened by over-representative analysis identified the five modules significantly associated with the HOT lesions. Pathway enrichment analysis, together with causal network analysis, revealed pathways of ribosome-associated quality controls, heat shock response by oxidative stress and hypoxia, angiogenesis, and oxidative phosphorylation. A semi-quantitative correlation of key-protein expressions, protein co-regulation analysis, and multivariate correlation analysis suggested co-regulations via network-network interaction among the four HOT-characteristic modules. Predicted highly activated master and upstream regulators were most characteristic to ER-positive breast cancer and associated with oncogenic transformation, as well as resistance to chemotherapy and endocrine therapy. Interestingly, inhibited intervention causal networks of numerous chemical inhibitors were predicted within the top 10 lists for the WM2 and WM5 modules, suggesting involvement of potential therapeutic targets in those data-driven networks. Our findings may help develop therapeutic strategies to benefit patients.

Capitalizing on Synthetic Lethality of MYC to Treat Cancer in the Digital Age

Deregulation of MYC is among the most frequent oncogenic drivers of cancer. Developing targeted therapies against MYC is, therefore, one of the most critical unmet needs of cancer therapy. Unfortunately, MYC has been labelled as undruggable due to the lack of success in developing clinically relevant MYC-targeted therapies. Synthetic lethality is a promising approach that targets MYC-dependent vulnerabilities in cancer. However, translating the synthetic lethality targets to the clinics is still challenging due to the complex nature of cancers. This review highlights the most promising mechanisms of MYC synthetic lethality and how these discoveries are currently translated into the clinic. Finally, we discuss how in silico computational platforms can improve clinical success of synthetic lethality-based therapy.

The role of tumor suppressor short non-coding RNAs on breast cancer

Characterized by remarkable levels of aggression and malignancy, BC remains one of the leading causes of death in females world wide. Accordingly, significant efforts have been made to develop early diagnostic tools, increase treatment efficacy, and improve patient prognosis. Hopefully, many of the molecular mechanisms underlying BC have been detected and show promising targeting potential. In particular, short and long non-coding RNAs (ncRNAs) are a class of endogenous BC controllers and include a number of different species including microRNAs, Piwi-interacting RNAs, small nucleolar RNA, short interfering RNAs, and tRNA-derivatives. In this review, we discuss the tumor suppressing roles of ncRNAs in the context of BC, and the mechanisms by which ncRNAs target tumor hallmarks, including apoptosis, proliferation, invasion, metastasis, epithelial-mesenchymal transition, angiogenesis, and cell cycle progression, in addition to their diagnostic and prognostic significance in cancer treatment.

The Molecular 'Myc-anisms' Behind Myc-Driven Tumorigenesis and the Relevant Myc-Directed Therapeutics

MYC, a well-studied proto-oncogene that is overexpressed in >20% of tumors across all cancers, is classically known as “undruggable” due to its crucial roles in cell processes and its lack of a drug binding pocket. Four decades of research and creativity led to the discovery of a myriad of indirect (and now some direct!) therapeutic strategies targeting Myc. This review explores the various mechanisms in which Myc promotes cancer and highlights five key therapeutic approaches to disrupt Myc, including transcription, Myc-Max dimerization, protein stability, cell cycle regulation, and metabolism, in order to develop more specific Myc-directed therapies.

Identification of candidate biomarkers correlated with the pathogenesis and prognosis of breast cancer via integrated bioinformatics analysis

BACKGROUND

This study was carried out to identify potential key genes associated with the pathogenesis and prognosis of breast cancer (BC).

METHODS

Seven GEO datasets (GSE24124, GSE32641, GSE36295, GSE42568, GSE53752, GSE70947, GSE109169) were downloaded from the Gene Expression Omnibus (GEO) database. Differentially expressed genes (DEGs) between BC and normal breast tissue samples were screened by an integrated analysis of multiple gene expression profile datasets. Hub genes related to the pathogenesis and prognosis of BC were verified by employing protein-protein interaction (PPI) network.

RESULTS

Ten hub genes with high degree were identified, including CDK1, CDC20, CCNA2, CCNB1, CCNB2, BUB1, BUB1B, CDCA8, KIF11, and TOP2A. Lastly, the Kaplan-Meier plotter (KM plotter) online database demonstrated that higher expression levels of these genes were related to lower overall survival. Experimental validation showed that all 10 hub genes had the same expression trend as predicted.

CONCLUSION

The findings of this research would provide some directive significance for further investigating the diagnostic and prognostic biomarkers to facilitate the molecular targeting therapy of BC, which could be used as a new biomarker for diagnosis and to guide the combination medicine of BC.

Identification of hub genes and small molecule therapeutic drugs related to breast cancer with comprehensive bioinformatics analysis

Breast cancer is one of the most common malignant tumors among women worldwide and has a high morbidity and mortality. This research aimed to identify hub genes and small molecule drugs for breast cancer by integrated bioinformatics analysis. After downloading multiple gene expression datasets from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) database, 283 overlapping differentially expressed genes (DEGs) significantly enriched in different cancer-related functions and pathways were obtained using LIMMA, VennDiagram and ClusterProfiler packages of R. We then analyzed the topology of protein–protein interaction (PPI) network with overlapping DEGs and further obtained six hub genes (RRM2, CDC20, CCNB2, BUB1B, CDK1, and CCNA2) from the network via STRING and Cytoscape. Subsequently, we conducted genes expression verification, genetic alterations evaluation, immune infiltration prediction, clinicopathological parameters analysis, identification of transcriptional and post-transcriptional regulatory molecules, and survival analysis for these hub genes. Meanwhile, 29 possible drug candidates (e.g., Cladribine, Gallium nitrate, Alvocidib, 1β-hydroxyalantolactone, Berberine hydrochloride, Nitidine chloride) were identified from the DGIdb database and the GSE85871 dataset. In addition, some transcription factors and miRNAs (e.g., E2F1, PTTG1, TP53, ZBTB16, hsa-miR-130a-3p, hsa-miR-204-5p) targeting hub genes were identified as key regulators in the progression of breast cancer. In conclusion, our study identified six hub genes and 29 potential drug candidates for breast cancer. These findings may advance understanding regarding the diagnosis, prognosis and treatment of breast cancer.

NOB1: A Potential Biomarker or Target in Cancer

Human NIN1/RPN12 binding protein 1 homolog (NOB1), an RNA binding protein, is expressed ubiquitously in normal tissues such as the lung, liver, and spleen. Its core physiological function is to regulate protease activities and participate in maintaining RNA metabolism and stability. NOB1 is overexpressed in a variety of cancers, including pancreatic cancer, non-small cell lung cancer, ovarian cancer, prostate carcinoma, osteosarcoma, papillary thyroid carcinoma, colorectal cancer, and glioma. Although existing data indicate that NOB1 overexpression is associated with cancer growth, invasion, and poor prognosis, the molecular mechanisms behind these effects and its exact roles remain unclear. Several studies have confirmed that NOB1 is clinically relevant in different cancers, and further research at the molecular level will help evaluate the role of NOB1 in tumors. NOB1 has become an attractive target in anticancer therapy because it is overexpressed in many cancers and mediates different stages of tumor development. Elucidating the role of NOB1 in different signaling pathways as a potential cancer treatment will provide new ideas for existing cancer treatment methods. This review summarizes the research progress made into NOB1 in cancer in the past decade; this information provides valuable clues and theoretical guidance for future anticancer therapy by targeting NOB1.

Upregulated cyclins may be novel genes for triple-negative breast cancer based on bioinformatic analysis

BACKGROUND

Triple-negative breast cancer (TNBC) is one of the leading causes of death among females around the world. However, the molecular mechanism of the disease among TNBC patients remains to be further studied.

METHODS

In our study, four microarray data and two high throughput sequencing data were acquired from the GEO database, and the differentially expressed genes (DEGs) between TNBC and normal tissues had been analyzed. Analysis of functional enrichment and pathway enrichment of DEGs was conducted by the Funrich software, and protein-protein interaction (PPI) network gained from the STRING, and hub genes were confirmed by the Cytoscape. Kaplan-Meier plotter (KM plotter) online dataset had been used to analyze DEGs of overall survival (OS), and progression-free survival (PFS).

RESULTS

In total, 1638 DEGs were gained in our study covering 984 upregulated and 654 downregulated genes. Moreover, a PPI network was constructed, and cyclin-dependent kinase 1 (CDK1), cyclin B1 (CCNB1), and cyclin A2 (CCNA2) were found as top genes with higher node degrees. CDK1, CCNA2, and CCNB1were obviously enriched in the cell cycle. The top upregulated genes including CDK1, CCNB1, CCNA2, and PLK1 were overexpressed in TNBC, and correlated with worse OS in breast cancer. High expression of CCNB1 was correlated with worse PFS in TNBC (HR = 1.42, 95% CI: 1.04-1.94, P = 0.028). Besides, there was a correlation between CCNB1 and CDK1 in TNBC, as well as between CCNA2 and CDK1 (r = 0.804, P < 0.001; r = 0.577, P < 0.001, respectively).

CONCLUSION

Our results suggest that cyclin CDK1, CCNB1, and CCNA2 are overexpressed in TNBC and they could act as novel biomarkers for the diagnosis and treatment of TNBC.

Identification of Key Genes in Association with Progression and Prognosis in Cervical Squamous Cell Carcinoma

Cervical cancer remains a primary cause of female death in developing countries, but its prognosis can be greatly improved if patients are diagnosed earlier. In the present study, we screened the common differentially expressed genes (DEGs) of cervical squamous cell carcinoma (CESC) from dataset GSE7803, Gene Expression Omnibus, and The Cancer Genome Atlas databases. An integrated bioinformatics analysis was performed based on these DEGs for their enrichment in functions and pathways, interaction network, prognostic signature, and candidate molecular drugs. As a result, 164 (114 upregulated and 47 downregulated) DEGs of CESC were identified for further investigation. We then conducted the gene ontology term enrichment and Kyoto Encyclopedia of Genes and Genomes Pathway analyses to reveal the underlying functions and pathways of these DEGs. In the protein-protein interaction network, hub module and hub genes were identified. Five genes of significant prognostic value-DSG2, ITM2A, CENPM, RIBC2, and MEIS2-were identified by prognostic signature analysis and used to construct a risk linear model. Further validation and investigation suggested DSG2 might be a key gene in CESC prognosis. We then identified two candidate small molecules (trichostatin A and tanespimycin) against CESC. Further validation and exploration of these hub genes are warranted for future prospect in clinical applications.

Inhibition of Heat Shock Protein 90 as a Novel Platform for the Treatment of Cancer

Heat shock protein 90 (Hsp90) plays an essential role in various physiological and pathological processes. It activates client proteins to participate in tumor progression. Blocking Hsp90 could enable effective antitumor effects in many tumor types, such as multiple myeloma and colon cancer. Recently, it has motivated an interest in Hsp90 inhibitors that bind to the N-terminal or C-terminal ATP pocket as antitumor drugs. We reviewed the data from experimental and clinical trials on Hsp90 inhibitors in the treatment of different malignancies to explore and summarize their antitumor mechanisms.