Targeting CDC7 improves sensitivity to chemotherapy of esophageal squamous cell carcinoma

Effective sequential combined therapy with carboplatin and a CDC7 inhibitor in ovarian cancer

BACKGROUND

The enhancement of DNA damage repair is one of the important mechanisms of platinum resistance. Protein cell division cycle 7 (CDC7) is a conserved serine/threonine kinase that plays important roles in the initiation of DNA replication and is associated with chemotherapy resistance in ovarian cancer. However, whether the CDC7 inhibitor XL413 has antitumor activity against ovarian cancer and its relationship with chemosensitivity remain poorly elucidated.

METHODS

We evaluated the antitumor effects of carboplatin combined with XL413 for ovarian cancer in vitro and in vivo. Cell viability inhibition, colony formation and apoptosis were assessed. The molecules related to DNA repair and damage were investigated. The antitumor effects of carboplatin combined with XL413 were also evaluated in SKOV-3 and OVCAR-3 xenografts in subcutaneous and intraperitoneal tumor models.

RESULTS

Sequential administration of XL413 after carboplatin (CBP) prevented cellular proliferation and promoted apoptosis in ovarian cancer (OC) cells. Compared with the CBP group, the expression level of RAD51 was significantly decreased and the expression level of γH2AX was significantly increased in the sequential combination treatment group. The equential combination treatment could significantly inhibit tumor growth in the subcutaneous and intraperitoneal tumor models, with the expression of RAD51 and Ki67 significantly decreased and the expression of γH2AX increased.

CONCLUSIONS

Sequential administration of CDC7 inhibitor XL413 after carboplatin can enhance the chemotherapeutic effect of carboplatin on ovarian cancer cells. The mechanism may be that CDC7 inhibitor XL413 increases the accumulation of chemotherapy-induced DNA damage by inhibiting homologous recombination repair activity.

A demonstration based on multi-omics transcriptome sequencing data revealed disulfidptosis heterogeneity within the tumor microenvironment of esophageal squamous cell carcinoma

BACKGROUND

It is of great concern to identify prognostic signatures for the prediction and prediction of esophageal squamous cell carcinoma (ESCC), which is the lethal pathological type of malignancy.

METHOD

Bulk RNA sequencing and scRNA-seq data were retrieved from GSE53624, GSE53622, and GSE188900. Disulfidptosis-related differentially expressed genes (DEGs) were identified between disulfidptosis-high score and disulfidptosis-low score groups. Functional annotation of DEGs were analyzed by Gene Ontology (GO). Consistent clustering and co-expression modules were analyzed, and then constructed a risk score model via multivariate Cox regression analysis. Immune infiltration and immunotherapy response analyses were conducted based on risk score. qRT-PCR, colony formation assay, and flow cytometry analysis were conducted in KYSE-150 and TE-1 cell lines.

RESULTS

Seven genes (CD96, CXCL13, IL2RG, LY96, TPK1, ACAP1, and SOX17) were selected as marker genes. CD96 and SOX17 are independent prognostic signatures for ESCC patients, with a significant correlation with infiltrated immune cells. ESCC patients had worse response to nivolumab in the high-risk group. Through cellular experiments, we found that CD96 expression was associated with apoptosis and cell cycle ESCC cells.

CONCLUSION

In a word, the risk score based on disulfidptosis is associated with prognosis and the immune microenvironment, which may direct immunotherapy of ESCC. The key gene of risk score, namely CD96, plays a role in proliferation and apoptosis in ESCC. We offer an insight into the exploration of the genomic etiology of ESCC for its clinical management.

A phase 1 open-label study to assess the relative bioavailability of TAK-931 tablets in reference to powder-in-capsule in patients with advanced solid tumors

In this phase 1 open-label study, we assessed the relative bioavailability of a prototype tablet formulation of TAK-931, a cell division cycle 7 kinase inhibitor, in reference to the current powder-in-capsule (PIC) formulation in patients with advanced solid tumors for whom no effective standard treatment was available. Adult patients were randomized 1:1 in a crossover fashion to receive one dose of TAK-931 80 mg PIC on Day 1 and one dose of TAK-931 80 mg tablet on Day 3 (or the reverse sequence), followed by TAK-931 50 mg PIC once daily (QD) for 12 days starting from Day 5, before a 7-day rest period (Cycle 0). From Cycle 1, all patients received 50 mg PIC QD on Days 1-14 followed by a 7-day rest period. Twenty patients were enrolled. Median T_max was achieved approximately 2 h post-dose of TAK-931 80 mg for both tablet and PIC. Geometric mean C_max, AUC exposures, and T_1/2z of TAK-931 were similar for both formulations. Geometric mean C_max, AUC_last, and AUC_inf ratios were 0.936 (90% confidence interval [CI]: 0.808-1.084), 1.004 (90% CI: 0.899-1.120), and 1.007 (90% CI: 0.903-1.123), respectively, for TAK-931 tablet in reference to PIC. Discontinuation of TAK-931 due to treatment-emergent adverse events (TEAEs) occurred in 1 patient. Four (20%) patients experienced a serious TEAE; none were considered related to TAK-931. Pharmacokinetics and systemic exposure profiles were similar following administration of both formulations, supporting the transition from PIC to tablet in the clinical development of TAK-931. (Trial registration number ClinicalTrials.gov NCT03708211. Registration date October 12, 2018).

Safety, Tolerability, and Pharmacokinetics of TAK-931, a Cell Division Cycle 7 Inhibitor, in Patients with Advanced Solid Tumors: A Phase I First-in-Human Study

Purpose:

We conducted a first-in-human, dose-escalation study, to evaluate the safety, tolerability, pharmacokinetics, pharmacodynamics, and activity of TAK-931, a cell division cycle 7 inhibitor, in Japanese patients with advanced solid tumors.

Experimental Design:

Patients ages ≥20 years received oral TAK-931: once daily for 14 days in 21-day cycles (schedule A; from 30 mg); once daily or twice daily for 7 days on, 7 days off in 28-day cycles (schedule B; from 60 mg); continuous once daily (schedule D; from 20 mg); or once daily for 2 days on, 5 days off (schedule E; from 100 mg) in 21-day cycles.

Results:

Of the 80 patients enrolled, all had prior systemic treatment and 86% had stage IV disease. In schedule A, 2 patients experienced dose-limiting toxicities (DLTs) of grade 4 neutropenia and the maximum tolerated dose (MTD) was 50 mg. In schedule B, 4 patients experienced DLTs of grade 3 febrile neutropenia (n = 3) or grade 4 neutropenia (n = 1); the MTD was 100 mg. Schedules D and E were discontinued before MTD determination. The most common adverse events were nausea (60%) and neutropenia (56%). Time to maximum plasma concentration of TAK-931 was approximately 1–4 hours postdose; systemic exposure was approximately dose proportional. Posttreatment pharmacodynamic effects correlating to drug exposure were observed. Overall, 5 patients achieved a partial response.

Conclusions:

TAK-931 was tolerable with a manageable safety profile. TAK-931 50 mg once daily days 1–14 in 21-day cycles was selected as a recommended phase II dose and achieved proof of mechanism.

Trial registration ID:

NCT02699749

Significance:

This was the first-in-human study of the CDC7 inhibitor, TAK-931, in patients with solid tumors. TAK-931 was generally tolerable with a manageable safety profile. The recommend phase II dose was determined to be TAK-931 50 mg administered once daily on days 1–14 of each 21-day cycle. A phase II study is ongoing to confirm the safety, tolerability, and antitumor activity of TAK-931 in patients with metastatic solid tumors.

CDC7 as a novel biomarker and druggable target in cancer

Due to the bottlenecks encountered in traditional treatment for tumor, more effective drug targets need to be developed. Cell division cycle 7 kinase plays an important role in DNA replication, DNA repair and recombination signaling pathways. In this review, we first describe recent studies on the role of CDC7 in DNA replication in normal human tissues, and then we integrate new evidence focusing on the important role of CDC7 in replication stress tolerance of tumor cells and its impact on the prognosis of clinical oncology patients. Finally, we comb through the CDC7 inhibitors identified in recent studies as a reference for further research in clinical practice.

Overexpression of cyclin-dependent kinase 1 in esophageal squamous cell carcinoma and its clinical significance

Cyclin‐dependent kinase 1 (CDK1) plays a significant role in certain malignancies. However, it remains unclear whether CDK1 plays a role in esophageal squamous cell carcinoma (ESCC). The aim of this study was to analyze the expression and clinical value of CDK1 in ESCC. CDK1 protein in 151 ESCC tissues and 138 normal esophageal tissues was detected by immunohistochemistry. RNA‐seq of eight pairs of ESCC and adjacent esophageal specimens was performed to evaluate the levels of CDK1 mRNA. Microarray and external RNA‐seq data from 664 cases of ESCC and 1733 cases of control tissues were used to verify the difference in CDK1 expression between the two groups. A comprehensive analysis of all data was performed to evaluate the difference in CDK1 between ESCC tissues and control tissues. Further, functional enrichment analyses were performed based on differentially expressed genes (DEGs) of ESCC and co‐expressed genes (CEGs) of CDK1. In addition, a lncRNA‐miRNA‐CDK1 network was constructed. The expression of CDK1 protein was obviously increased in ESCC tissues (3.540 ± 2.923 vs. 1.040 ± 1.632, P < 0.001). RNA‐seq indicated that the mRNA level of CDK1 was also highly expressed in ESCC tissues (5.261 ± 0.703 vs. 2.229 ± 1.161, P < 0.0001). Comprehensive analysis revealed consistent up‐regulation of CDK1 (SMD = 1.41; 95% CI 1.00–1.83). Further, functional enrichment analyses revealed that the functions of these genes were mainly concentrated in the cell cycle. A triple regulatory network of PVT1‐hsa‐miR‐145‐5p/hsa‐miR‐30c‐5p‐CDK1 was constructed using in silico analysis. In summary, overexpression of CDK1 is closely related to ESCC tumorigenesis.

Molecular Signature of Small Cell Lung Cancer after Treatment Failure: The MCM Complex as Therapeutic Target

Small cell lung cancer (SCLC) is a highly aggressive cancer, and patients who become refractory to first-line treatment have a poor prognosis. The development of effective treatment regimens is urgently needed. In this study, we identified a gene expression signature of SCLC after treatment failure using SCLC clinical specimens (GEO accession number: GSE162102). A total of 1,136 genes were significantly upregulated in SCLC tissues. These upregulated genes were subjected to KEGG pathway analysis, and "cell cycle", "Fanconi anemia", "alcoholism", "systemic lupus erythematosus", "oocyte meiosis", "homologous recombination", "DNA replication", and "p53 signaling" were identified as the enriched pathways among the genes. We focused on the cell cycle pathway and investigated the clinical significance of four genes associated with this pathway: minichromosome maintenance (MCM) 2, MCM4, MCM6, and MCM7. The overexpression of these MCM genes was confirmed in SCLC clinical specimens. Knockdown assays using siRNAs targeting each of these four MCM genes showed significant attenuation of cancer cell proliferation. Moreover, siRNA-mediated knockdown of each MCM gene enhanced the cisplatin sensitivity of SCLC cells. Our SCLC molecular signature based on SCLC clinical specimens after treatment failure will provide useful information to identify novel molecular targets for this disease.

MicroRNA-29b targeting of cell division cycle 7-related protein kinase (CDC7) regulated vascular smooth muscle cell (VSMC) proliferation and migration

Background

Proliferation and migration of vascular smooth muscle cells (VSMCs) are vital processes in vascular remodeling and pathology. This study aimed to explore the expression of miR-29b and cell division cycle 7-related protein kinase (CDC7) in patients with cerebral aneurysm (CA) and their effects on the proliferation and mobility of human umbilical artery smooth muscle cells (HUASMCs).

Methods

RNA levels of miR-29b and CDC7 were evaluated in the CA tissues and adjacent normal cerebral arteries from 18 patients undergoing surgery for CA rupture. The targeting of CDC7 by miR-29b was verified with luciferase reporter assay. Both CDC7 and miR-29b overexpression and silencing vectors were introduced to validate their effects on the proliferation and mobility of HUASMCs.

Results

The mRNA level of miR-29b was down-regulated (P<0.05), while the mRNA level of CDC7 was markedly elevated in CA patients (P<0.05). A Luciferase reporter assay showed CDC7 is a target gene of miR-29b, and miR-29b mimic down-regulated the mRNA and protein levels of CDC7 (P<0.05). Furthermore, miR-29b mimic inhibited, while miR-29b inhibitor or CDC7 over-expression promoted the proliferation and mobility of HUASMCs (P<0.05).

Conclusions

miR-29-3p inhibits cell proliferation and mobility via directly targeting CDC7, which could be a potential therapeutic target for vascular dysfunction related diseases, including atherosclerosis and CA.

Structural Basis for the Activation and Target Site Specificity of CDC7 Kinase

CDC7 is an essential Ser/Thr kinase that acts upon the replicative helicase throughout the S phase of the cell cycle and is activated by DBF4. Here, we present crystal structures of a highly active human CDC7-DBF4 construct. The structures reveal a zinc-finger domain at the end of the kinase insert 2 that pins the CDC7 activation loop to motif M of DBF4 and the C lobe of CDC7. These interactions lead to ordering of the substrate-binding platform and full opening of the kinase active site. In a co-crystal structure with a mimic of MCM2 Ser40 phosphorylation target, the invariant CDC7 residues Arg373 and Arg380 engage phospho-Ser41 at substrate P+1 position, explaining the selectivity of the S-phase kinase for Ser/Thr residues followed by a pre-phosphorylated or an acidic residue. Our results clarify the role of DBF4 in activation of CDC7 and elucidate the structural basis for recognition of its preferred substrates.

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DBF4 activates CDC7 kinase via a two-step mechanism

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Zinc-finger domain in CDC7 KI2 interacts with DBF4 motif M

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Invariant CDC7 residues Arg373 and Arg380 engage P+1 substrate site