Aberrant TIMELESS expression is associated with poor clinical survival and lymph node metastasis in early-stage cervical carcinoma

Reactivation of methylation-silenced PAX1 inhibits cervical cancer proliferation and migration via the WNT/TIMELESS pathway

Although aberrant methylation of PAX1 is closely associated with cervical cancer (CC), PAX1 methylation (PAX1m) and its role in CC remain to be elucidated. Here, we clarified the biological function of PAX1 in CC. First, PAX1m in ThinPrep cytologic test samples was measured via quantitative methylation-specific PCR. The results showed that PAX1 promoter methylation levels were significantly increased in CC patients (p < 0.001). We also found that PAX1 promoter methylation levels were positively correlated with tumor purity but negatively correlated with immune-infiltration via public databases. Then, CRISPR-based methylation perturbation tools (dCas9-Tet1) were constructed to further demonstrate that DNA methylation participates in the regulation of PAX1 expression directly. Gain- and loss-of-function experiments were used to show that PAX1 overexpression restrained proliferation, migration and improved cisplatin sensitivity by interfering with the WNT/TIMELESS axis in CC cells. Additionally, Co-immunoprecipitation assays further confirmed the interaction between PAX1 and TCF7L2. Taken together, our results suggested that a tumor suppressor role of PAX1 in CC and that CRISPR-based PAX1 demethylation editing might be a promising therapeutic strategy for CC.

TIMELESS promotes reprogramming of glucose metabolism in oral squamous cell carcinoma

BACKGROUND

Oral squamous cell carcinoma (OSCC), the predominant malignancy of the oral cavity, is characterized by high incidence and low survival rates. Emerging evidence suggests a link between circadian rhythm disruptions and cancer development. The circadian gene TIMELESS, known for its specific expression in various tumors, has not been extensively studied in the context of OSCC. This study aims to explore the influence of TIMELESS on OSCC, focusing on cell growth and metabolic alterations.

METHODS

We analyzed TIMELESS expression in OSCC using western blot, immunohistochemistry, qRT-PCR, and data from The Cancer Genome Atlas (TCGA) and the Cancer Cell Line Encyclopedia (CCLE). The role of TIMELESS in OSCC was examined through clone formation, MTS, cell cycle, and EdU assays, alongside subcutaneous tumor growth experiments in nude mice. We also assessed the metabolic impact of TIMELESS by measuring glucose uptake, lactate production, oxygen consumption, and medium pH, and investigated its effect on key metabolic proteins including silent information regulator 1 (SIRT1), hexokinase 2 (HK2), pyruvate kinase isozyme type M2 (PKM2), recombinant lactate dehydrogenase A (LDHA) and glucose transporter-1 (GLUT1).

RESULTS

Elevated TIMELESS expression in OSCC tissues and cell lines was observed, correlating with reduced patient survival. TIMELESS overexpression enhanced OSCC cell proliferation, increased glycolytic activity (glucose uptake and lactate production), and suppressed oxidative phosphorylation (evidenced by reduced oxygen consumption and altered pH levels). Conversely, TIMELESS knockdown inhibited these cellular and metabolic processes, an effect mirrored by manipulating SIRT1 levels. Additionally, SIRT1 was positively associated with TIMELESS expression. The expression of SIRT1, HK2, PKM2, LDHA and GLUT1 increased with the overexpression of TIMELESS levels and decreased with the knockdown of TIMELESS.

CONCLUSION

TIMELESS exacerbates OSCC progression by modulating cellular proliferation and metabolic pathways, specifically by enhancing glycolysis and reducing oxidative phosphorylation, largely mediated through the SIRT1 pathway. This highlights TIMELESS as a potential target for OSCC therapeutic strategies.

The TIMELESS Roles in Genome Stability and Beyond

TIMELESS protein (TIM) protects replication forks from stalling at difficult-to-replicate regions and plays an important role in DNA damage response, including checkpoint signaling, protection of stalled replication forks and DNA repair. Loss of TIM causes severe replication stress, while its overexpression is common in various types of cancer, providing protection from DNA damage and resistance to chemotherapy. Although TIM has mostly been studied for its part in replication stress response, its additional roles in supporting genome stability and a wide variety of other cellular pathways are gradually coming to light. This review discusses the diverse functions of TIM and its orthologs in healthy and cancer cells, open questions, and potential future directions.

Profiling of Lymphovascular Space Invasion in Cervical Cancer Revealed PI3K/Akt Signaling Pathway Overactivation and Heterogenic Tumor-Immune Microenvironments

Lymphovascular space invasion (LVSI) is the presence of tumor emboli in the endothelial-lined space at the tumor body's invasive edge. LVSI is one of three Sedlis criteria components-a prognostic tool for early cervical cancer (CC)-essential for indicating poor prognosis, such as lymph node metastasis, distant metastasis, or shorter survival rate. Despite its clinical significance, an in-depth comprehension of the molecular mechanisms or immune dynamics underlying LVSI in CC remains elusive. Therefore, this study investigated tumor-immune microenvironment (TIME) dynamics of the LVSI-positive group in CC. RNA sequencing included formalin-fixed paraffin-embedded (FFPE) slides from 21 CC patients, and differentially expressed genes (DEGs) were analyzed. Functional analysis and immune deconvolution revealed aberrantly enriched PI3K/Akt pathway activation and a heterogenic immune composition with a low abundance of regulatory T cells (Treg) between LVSI-positive and LVSI-absent groups. These findings improve the comprehension of LSVI TIME and immune mechanisms, benefiting targeted LVSI therapy for CC.

An integrative evaluation of circadian gene TIMELESS as a pan-cancer immunological and predictive biomarker

BACKGROUND

The gene TIMELESS, which is involved in the circadian clock and the cell cycle, has recently been linked to various human cancers. Nevertheless, the association between TIMELESS expression and the prognosis of individuals afflicted with pan-cancer remains largely unknown.

OBJECTIVES

The present study aims to exhaustively scrutinize the expression patterns, functional attributes, prognostic implications, and immunological contributions of TIMELESS across diverse types of human cancer.

METHODS

The expression of TIMELESS in normal and malignant tissues was examined, as well as their clinicopathologic and survival data. The characteristics of genetic alteration and molecular subtypes of cancers were also investigated. In addition, the relationship of TIMELESS with immune infiltration, tumor mutation burden (TMB), microsatellite instability (MSI), and drug sensitivity was illustrated. Immunohistochemistry (IHC) was used to validate the expression of TIMELESS in clinical patients with several types of cancer.

RESULTS

In contrast to the matching normal controls, most tumor types were found to often overexpress TIMELESS. Abnormal expression of TIMELESS was significantly related to more advanced tumor stage and poorer prognosis of breast cancer, as well as infiltrating immune cells such as cancer-associated fibroblast infiltration in various tumors. Multiple cancer types exhibited abnormal expression of TIMELESS, which was also highly correlated with MSI and TMB. More crucially, TIMELESS showed promise in predicting the effectiveness of immunotherapy and medication sensitivity in cancer therapy. Moreover, cell cycle, DNA replication, circadian rhythm, and mismatch repair were involved in the functional mechanisms of TIMELESS on carcinogenesis. Furthermore, immunohistochemical results manifested that the TIMELESS expression was abnormal in some cancers.

CONCLUSIONS

This study provides new insights into the link between the circadian gene TIMELESS and the development of various malignant tumors. The findings suggest that TIMELESS could be a prospective prognostic and immunological biomarker for pan-cancer.

Six-hour time-restricted feeding inhibits lung cancer progression and reshapes circadian metabolism

BACKGROUND

Accumulating evidence has suggested an oncogenic effect of diurnal disruption on cancer progression. To test whether targeting circadian rhythm by dietary strategy suppressed lung cancer progression, we adopted 6-h time-restricted feeding (TRF) paradigm to elucidate whether and how TRF impacts lung cancer progression.

METHODS

This study used multiple lung cancer cell lines, two xenograft mouse models, and a chemical-treated mouse lung cancer model. Stable TIM-knockdown and TIM-overexpressing A549 cells were constructed. Cancer behaviors in vitro were determined by colony formation, EdU proliferation, wound healing, transwell migration, flow cytometer, and CCK8 assays. Immunofluorescence, pathology examinations, and targeted metabolomics were also used in tumor cells and tissues. mCherry-GFP-LC3 plasmid was used to detect autophagic flux.

RESULTS

We found for the first time that compared to normal ad libitum feeding, 6-h TRF inhibited lung cancer progression and reprogrammed the rhythms of metabolites or genes involved in glycolysis and the circadian rhythm in tumors. After TRF intervention, only timeless (TIM) gene among five lung cancer-associated clock genes was found to consistently align rhythm of tumor cells to that of tumor tissues. Further, we demonstrated that the anti-tumor effect upon TRF was partially mediated by the rhythmic downregulation of the TIM and the subsequent activation of autophagy. Combining TRF with TIM inhibition further enhanced the anti-tumor effect, comparable to treatment efficacy of chemotherapy in xenograft model.

CONCLUSIONS

Six-hour TRF inhibits lung cancer progression and reshapes circadian metabolism, which is partially mediated by the rhythmic downregulation of the TIM and the subsequent upregulation of autophagy.

Association of the Timeless Gene with Prognosis and Clinical Characteristics of Human Lung Cancer

(1) Background: As the most common malignant tumor type worldwide, it is necessary to identify novel potential prognostic biomarkers to improve the poor prognosis of lung cancer. The Timeless gene, a circadian rhythm-related gene, is associated with several types of cancer. However, studies analyzing the clinical significance of the Timeless gene in patients with lung cancer are currently limited. (2) Methods: In the present study, the expression levels and prognostic potential of the Timeless gene and its co-expressed genes in different subtypes of lung cancer were explored using multiple bioinformatics approaches. The correlations between the Timeless gene and its co-expressed genes were validated using A549 and NCI-H226 cells by transfecting them with expression vectors and analyses using Western blot and reverse transcription-quantitative PCR. (3) Results: The Oncomine and GEPIA database analyses indicated that the expression of the Timeless gene was significantly higher in lung cancer as compared to that in the normal tissue. Using the UALCAN database, significant differences in Timeless gene expression were determined among different stages of lung cancer and between genders. A Kaplan-Meier plotter analysis indicated that high expression of the Timeless gene was associated with poor overall survival (OS) and progression-free survival (PFS) of patients with lung cancer. In the cBioPortal and GEPIA database analyses, extra spindle pole bodies like 1 (ESPL1) was the top correlated gene of Timeless in patients with lung cancer. Similar to the Timeless gene, high expression of the ESPL1 gene was also associated with poor OS and PFS. Of note, overexpression of the Timeless gene increased the expression level of ESPL1 at both the mRNA and protein levels. (4) Conclusion: The present study explored the clinical significance of the Timeless gene and its correlated gene ESPL1 in patients with lung cancer, thereby providing a potential therapeutic target for lung cancer.

Identification of TIMELESS and RORA as key clock molecules of non-small cell lung cancer and the comprehensive analysis

Background

The incidence rate of non-small cell lung cancer (NSCLC) has been increasing worldwide, and the correlation of circadian rhythm disruption with a raised risk of cancer and worse prognosis has been shown by accumulating evidences recently. On the other hand, drug resistance and the impact of tumor heterogeneity have been inevitable in NSCLC therapy. These both lead to an urgent need to identify more useful prognostic and predictive markers for NSCLC diagnosis and treatment, especially on the aspect of circadian clock genes.

Methods

The expression of the main clock genes in cancer was probed with TIMER and Oncomine databases. The prognostic value of key clock genes was probed systematically with the Kaplan–Meier estimate and Cox regression on samples from TCGA database. RT-qPCR was performed on patient tissue samples to further validate the results from databases. The functional enrichment analysis was performed using the “ClusterProfiler” R package, and the correlation of key clock genes with tumor mutation burden, immune checkpoint, and immune infiltration levels were also assessed using multiple algorithms including TIDE, TIMER2.0, and XCELL.

Results

TIMELESS was significantly upregulated in lung tissue of clinical lung cancer patients as well as TCGA and Oncomine databases, while RORA was downregulated. Multivariate Cox regression analysis indicated that TIMELESS (P = 0.004, HR = 1.21 [1.06, 1.38]) and RORA (P = 0.047, HR = 0.868 [0.755, 0.998]) has a significant correlation with overall survival in NSCLC. Genes related to TIMELESS were enriched in the cell cycle and immune system, and the function of RORA was mainly focused on oncogenic signaling pathways or glycosylation and protein activation. Also, TIMELESS was positively correlated with tumor mutation burden while RORA was negatively correlated with it. TIMELESS and RORA were also significantly correlated with immune checkpoint and immune infiltration levels in NSCLC. Additionally, TIMELESS showed a significant positive relationship with lipid metabolism.

Conclusions

TIMELESS and RORA were identified as key clock genes in NSCLC, and were independent prognostic factors for overall survival in NSCLC. The function of them were assessed in many aspects, indicating the strong potential of the two genes to serve as biomarkers for NSCLC progression and prognosis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-022-09203-1.

Loss of circadian gene Timeless induces EMT and tumor progression in colorectal cancer via Zeb1-dependent mechanism

The circadian gene Timeless (TIM) provides a molecular bridge between circadian and cell cycle/DNA replication regulatory systems and has been recently involved in human cancer development and progression. However, its functional role in colorectal cancer (CRC), the third leading cause of cancer-related deaths worldwide, has not been fully clarified yet. Here, the analysis of two independent CRC patient cohorts (total 1159 samples) reveals that loss of TIM expression is an unfavorable prognostic factor significantly correlated with advanced tumor stage, metastatic spreading, and microsatellite stability status. Genome-wide expression profiling, in vitro and in vivo experiments, revealed that TIM knockdown induces the activation of the epithelial-to-mesenchymal transition (EMT) program. Accordingly, the analysis of a large set of human samples showed that TIM expression inversely correlated with a previously established gene signature of canonical EMT markers (EMT score), and its ectopic silencing promotes migration, invasion, and acquisition of stem-like phenotype in CRC cells. Mechanistically, we found that loss of TIM expression unleashes ZEB1 expression that in turn drives the EMT program and enhances the aggressive behavior of CRC cells. Besides, the deranged TIM-ZEB1 axis sets off the accumulation of DNA damage and delays DNA damage recovery. Furthermore, we show that the aggressive and genetically unstable 'CMS4 colorectal cancer molecular subtype' is characterized by a lower expression of TIM and that patients with the combination of low-TIM/high-ZEB1 expression have a poorer outcome. In conclusion, our results as a whole suggest the engagement of an unedited TIM-ZEB1 axis in key pathological processes driving malignant phenotype acquisition in colorectal carcinogenesis. Thus, TIM-ZEB1 expression profiling could provide a robust prognostic biomarker in CRC patients, supporting targeted therapeutic strategies with better treatment selection and patients' outcomes.

DDK/Hsk1 phosphorylates and targets fission yeast histone deacetylase Hst4 for degradation to stabilize stalled DNA replication forks

In eukaryotes, paused replication forks are prone to collapse, which leads to genomic instability, a hallmark of cancer. Dbf4-dependent kinase (DDK)/Hsk1^Cdc7 is a conserved replication initiator kinase with conflicting roles in replication stress response. Here, we show that fission yeast DDK/Hsk1 phosphorylates sirtuin, Hst4 upon replication stress at C-terminal serine residues. Phosphorylation of Hst4 by DDK marks it for degradation via the ubiquitin ligase SCF^pof3. Phosphorylation-defective hst4 mutant (4SA-hst4) displays defective recovery from replication stress, faulty fork restart, slow S-phase progression and decreased viability. The highly conserved fork protection complex (FPC) stabilizes stalled replication forks. We found that the recruitment of FPC components, Swi1 and Mcl1 to the chromatin is compromised in the 4SA-hst4 mutant, although whole cell levels increased. These defects are dependent upon H3K56ac and independent of intra S-phase checkpoint activation. Finally, we show conservation of H3K56ac-dependent regulation of Timeless, Tipin, and And-1 in human cells. We propose that degradation of Hst4 via DDK increases H3K56ac, changing the chromatin state in the vicinity of stalled forks facilitating recruitment and function of FPC. Overall, this study identified a crucial role of DDK and FPC in the regulation of replication stress response with implications in cancer therapeutics.

Activation of the clock gene TIMELESS by H3k27 acetylation promotes colorectal cancer tumorigenesis by binding to Myosin-9

BACKGROUND

Colorectal cancer (CRC) is a common tumor characterized by its high mortality. However, the underlying molecular mechanisms that drive CRC tumorigenesis are unclear. Clock genes have important roles in tumor development. In the present study, the expression and functions of clock gene TIMELESS (encoding the Timeless protein) in CRC were investigated.

METHODS

Immunohistochemistry, cell proliferation, migration, invasion, EMT and xenograft tumor experiments were used to prove the function of Timeless in the tumorigenesis of CRC. Immunoprecipitation, mass spectrometry, Immunofluorescence and Chromatin immunoprecipitation (ChIP) were utilized to clarify the mechanism of Timeless in regulating CRC tumorigenesis.

RESULTS

We found that Timeless was upregulated in CRC tissues compared with corresponding normal tissues and its expression was closely associated with the TNM stages and overall survival of CRC patients. Functional studies demonstrated that Timeless promoted the proliferation, invasion, and EMT of CRC cells in vitro and in vivo. Mechanistic investigations showed that Timeless activated the β-catenin signal pathway by binding to Myosin-9, which binds to β-catenin to induce its nuclear translocation. The upregulation of Timeless was attributed to CREB-binding protein (CBP)/p300-mediated H3K27 acetylation of the promoter region of Timeless.

CONCLUSION

Timeless regulates the tumorigenesis of CRC by binding to and regulating myosin-9, suggesting Timeless might be a potential prognostic biomarker and therapeutic target for CRC.

Circadian clock genes promote glioma progression by affecting tumour immune infiltration and tumour cell proliferation

Objectives

Circadian rhythm controls complicated physiological activities in organisms. Circadian clock genes have been related to tumour progression, but its role in glioma is unknown. Therefore, we explored the relationship between dysregulated circadian clock genes and glioma progression.

Materials and Methods

Samples were divided into different groups based on circadian clock gene expression in training dataset (n = 672) and we verified the results in other four validating datasets (n = 1570). The GO and GSEA enrichment analysis were conducted to explore potential mechanism of how circadian clock genes affected glioma progression. The single‐cell RNA‐Seq analysis was conducted to verified previous results. The immune landscape was evaluated by the ssGSEA and CIBERSORT algorithm. Cell proliferation and viability were confirmed by the CCK8 assay, colony‐forming assay and flow cytometry.

Results

The cluster and risk model based on circadian clock gene expression can predict survival outcome. Samples were scoring by the least absolute shrinkage and selection operator regression analysis, and high scoring tumour was associated with worse survival outcome. Samples in high‐risk group manifested higher activation of immune pathway and cell cycle. Tumour immune landscape suggested high‐risk tumour infiltrated more immunocytes and more sensitivity to immunotherapy. Interfering TIMELESS expression affected circadian clock gene expression, inhibited tumour cell proliferation and arrested cell cycle at the G0/G1 phase.

Conclusions

Dysregulated circadian clock gene expression can affect glioma progression by affecting tumour immune landscape and cell cycle. The risk model can predict glioma survival outcome, and this model can also be applied to pan‐cancer.

Analysis of diagnostic and prognostic value of lncRNA MEG3 in cervical cancer

The present study aimed to explore the diagnostic and prognostic value of lncRNA maternally expressed 3 (MEG3) in cervical cancer. Eighty-four patients with cervical cancer from February 2013 to March 2014 were enrolled in the observation group (OG), and another 58 female subjects who underwent physical examination at Huangshi Central Hospital were enrolled as the control group (CG). The serum MEG3 expression of patients in the two groups was detected by RT-qPCR, and the ability of MEG3 to aid in the diagnosis of cervical cancer, lymph node metastasis and FIGO staging, as well as to predict mortality was evaluated by ROC curve. In addition, the patients in the OG were divided into high- and low-expression groups according to the median value of MEG3. Kaplan Meier was employed to analyze the survival status, and Cox regression to analyze the independent prognostic factors of cervical cancer patients. The results of the present study revealed that the serum MEG3 expression in the OG was significantly lower than that of the CG (P<0.05). The area under the curve (AUC) of MEG3 in diagnosing cervical cancer was 0.844, the AUC in predicting mortality was 0.858, while that in diagnosing lymph node transfer was 0.707, and that in diagnosing FIGO staging was 0.791. The 5-year survival rate of the high-expression group was higher than that of the low-expression group (P=0.020). Multivariate analysis indicated that MEG3 (HR, 0.173; 95 CI%, 0.028-0.919), lymph node metastasis (HR, 2.259; 95 CI%, 1.004-5.025) and FIGO staging (HR, 0.008; 95 CI%, 1.453-6.248) were independent prognostic factors for cervical cancer patients. Collectively, lncRNA MEG3 may be a diagnostic marker and prognostic indicator for cervical cancer, and has a certain diagnostic value for lymph node metastasis and FIGO staging. Lymph node metastasis, FIGO stage III and IV, and low MEG3 levels were revealed to be independent prognostic factors for cervical cancer patients.

Knock-down of the TIM/TIPIN complex promotes apoptosis in melanoma cells

The Timeless (TIM) and it's interacting partner TIPIN protein complex is well known for its role in replication checkpoints and normal DNA replication processes. Recent studies revealed the involvement of TIM and TIPIN in human malignancies; however, no evidence is available regarding the expression of the TIM/TIPIN protein complex or its potential role in melanoma. Therefore, we investigated the role of this complex in melanoma.

To assess the role of the TIM/TIPIN complex in melanoma, we analyzed TIM/TIPIN expression data from the publicly accessible TCGA online database, Western blot analysis, and RT-qPCR in a panel of melanoma cell lines. Lentivirus-mediated TIM/TIPIN knockdown in A375 melanoma cells was used to examine proliferation, colony formation, and apoptosis. A xenograft tumor formation assay was also performed.

The TIM/TIPIN complex is frequently overexpressed in melanoma cells compared to normal melanocytes. We also discovered that the overexpression of TIM and TIPIN was significantly associated with poorer prognosis of melanoma patients. Furthermore, we observed that shRNA-mediated knockdown of TIM and TIPIN reduced cell viability and proliferation due to the induction of apoptosis and increased levels of γH2AX, a marker of DNA damage. In a xenograft tumor nude mouse model, shRNA-knockdown of TIM/TIPIN significantly reduced tumor growth.

Our results suggest that the TIM/TIPIN complex plays an important role in tumorigenesis of melanoma, which might reveal novel approaches for the development of new melanoma therapies. Our studies also provide a beginning structural basis for understanding the assembly of the TIM/TIPIN complex. Further mechanistic investigations are needed to determine the complex’s potential as a biomarker of melanoma susceptibility. Targeting TIM/TIPIN might be a potential therapeutic strategy against melanoma.

Development and Validation of a Deep Learning Radiomics Model Predicting Lymph Node Status in Operable Cervical Cancer

Aim: To develop and validate a deep learning radiomics model, which could predict the lymph node metastases preoperatively in cervical cancer patients. Patients and methods: We included a cohort of 226 pathological proven operable cervical cancer patients in two academic medical institutions from December 2014 to November 2017. Then this dataset was split into training set (n = 176) and independent testing set (n = 50) randomly. Five radiomic features were selected and a radiomic signature was established. We then combined these five radiomic features with the preoperative tumor histology and grade of these patients together. Baseline logistic regression model (LRM) and support vector machine model (SVM) were established for the comparison. We then explored the performance of a deep neural network (DNN), which is a popular deep learning model nowadays. Finally, performance of this DNN was validated in another independent test set including 50 cases of operable cervical cancer patients. Results: One thousand forty-five radiomic features were extracted for each patient. Twenty-eight features were found to be significantly correlated with the lymph node status in these patients (P < 0.05). Five radiomic features were further selected for further study due to their higher predictive powers. Baseline LRM incorporating these five radiomic and two clinicopathological features was established, which had an area under receiver operating characteristic curve (ROC) of 0.7372 and an accuracy of 89.20%. The established DNN model had four neural layers, in which layer there were 10 neurons. Adagrad optimizer and 1,500 iterations were used in training. The trained DNN had an area under curve (AUC) of 0.99 and an accuracy of 97.16% in the internal validation. To exclude the overfitting, independent external validation was also performed. AUC and accuracy in test set could still retain 0.90 and 92.00% respectively. Conclusion: This study used deep learning method to provide a comprehensive predictive model using preoperative CT images, tumor histology, and grade in cervical cancer patients. This model showed an acceptable accuracy in the prediction of lymph node status in cervical cancer. Our model may help identifying those patients who could benefit a lot from radiation therapy rather than primary hysterectomy surgery if this model could resist strict testing of future randomized controlled trials (RCTs).

Aberrantly Expressed Timeless Regulates Cell Proliferation and Cisplatin Efficacy in Cervical Cancer

Timeless is a regulator of molecular clockwork in Drosophila and related to cancer development in mammals. This study aimed to investigate the effect of Timeless on cell proliferation and cisplatin sensitivity in cervical cancer. Timeless expression was determined by bioinformatics analysis, immunohistochemistry, and quantitative polymerase chain reaction (qPCR). Chromatin immunoprecipitation assays and reporter gene assays were applied to determine the transcriptional factor contributing to Timeless upregulation. The effects of Timeless depletion on cell proliferation and cisplatin sensitivity were determined through in vitro and in vivo experiments. Cell apoptosis and senescence were assessed by flow cytometry and β-galactosidase staining. DNA damage and DNA repair pathways were determined by comet assay, immunofluorescent staining, and Western blot analysis. Timeless is aberrantly expressed in ∼52.5% of cervical cancer tissues. E2F1 and E2F4 contribute to the transcriptional activation of Timeless. Timeless depletion inhibits cell proliferation and increases cisplatin sensitivity in vitro and in vivo. Knockdown of Timeless induces cell apoptosis and cell senescence. Mechanically, Timeless silencing leads to DNA damage and impairs the activation of the ATR/CHK1 pathway in response to cisplatin in cervical cancer. Timeless is overexpressed in cervical cancer and regulates cell proliferation and cisplatin sensitivity, presenting an attractive target for cisplatin sensitizer in cervical cancer.

MicroRNA-708 Suppresses Cell Proliferation and Enhances Chemosensitivity of Cervical Cancer Cells to cDDP by Negatively Targeting Timeless

Purpose

Cervical cancer is the fourth most common cause of cancer-associated mortality in women worldwide. Previous studies have reported that microRNAs (miRNAs) are involved in multiple biological aspects of cancer progression by regulating gene expression. Here, we investigated the role of microRNA-708 (miR-708) in cervical cancer.

Methods

The expression levels of miR-708 in cervical cancer tissues and paired-normal cervical tissues were tested by quantitative polymerase chain reaction (qPCR). The interaction between miR-708 and Timeless was identified by bioinformatics method, dual-luciferase reporter assay, and Western blotting. The effects of over-expression of miR-708 on cell proliferation and cisplatin sensitivity were determined by Cell Counting Kit-8 (CCK-8) and colony formation assay. Cell cycle and apoptosis were analyzed by flow cytometry. DNA damage induced by over-expression of miR-708 was determined by comet assay. Expression levels of the genes involved in repair of DNA damage were analyzed by Western blotting.

Results

MiR-708 was down-regulated in cervical cancer tissues compared with paired-normal cervical tissues. By bioinformatics method, Western blotting, and dual-luciferase reporter assay, we found that Timeless was a direct target of miR-708. Furthermore, miR-708 suppressed cellular viability, colony formation, promoted apoptosis, and induced DNA damage levels. MiR-708 also enhanced chemosensitivity of cervical cancer cells to cDDP via impairing the ATR/CHK1 signaling pathway.

Conclusion

We conclude that miR-708 suppresses cell proliferation, facilitates cisplatin efficacy, and impairs DNA repair pathway in cervical cancer cells. These results demonstrate that miR-708 might be a candidate therapeutic target for future cervical cancer therapy.

HOXC10 promotes gastric cancer cell invasion and migration via regulation of the NF-κB pathway

Homeobox gene C10 (HOXC10), known to regulate cell differentiation and proliferation, is upregulated in gastric cancer (GC). The mechanism underlying HOXC10 involvement in GC metastasis is unclear. Herein, we found that HOXC10 is overexpressed in GC relative to normal controls. In the 73 GC patients tissue microarrays (TMA) tested, HOXC10 expression was closely related with tumor-node-metastasis (TNM) stage, lymph node metastasis, and distant metastasis. HOXC10 overexpression tended to associate with low 5-year cumulative survival. Cox regression analysis identified HOXC10 as an independent prognostic factor for poor patient survival. HOXC10 promoted GC cell invasion and migration, regulated the expression of activated ATM and markers of NF-κB signaling. HOXC10 may promote invasion and migration of GC by regulating ATM/NF-κB signaling pathway. HOXC10 should be explored as a clinical marker of GC prognosis.

Overexpression of Claspin and Timeless protects cancer cells from replication stress in a checkpoint-independent manner

Oncogene-induced replication stress (RS) promotes cancer development but also impedes tumor growth by activating anti-cancer barriers. To determine how cancer cells adapt to RS, we have monitored the expression of different components of the ATR-CHK1 pathway in primary tumor samples. We show that unlike upstream components of the pathway, the checkpoint mediators Claspin and Timeless are overexpressed in a coordinated manner. Remarkably, reducing the levels of Claspin and Timeless in HCT116 cells to pretumoral levels impeded fork progression without affecting checkpoint signaling. These data indicate that high level of Claspin and Timeless increase RS tolerance by protecting replication forks in cancer cells. Moreover, we report that primary fibroblasts adapt to oncogene-induced RS by spontaneously overexpressing Claspin and Timeless, independently of ATR signaling. Altogether, these data indicate that enhanced levels of Claspin and Timeless represent a gain of function that protects cancer cells from of oncogene-induced RS in a checkpoint-independent manner.

At the Beginning of the End and in the Middle of the Beginning: Structure and Maintenance of Telomeric DNA Repeats and Interstitial Telomeric Sequences

Tandem DNA repeats derived from the ancestral (TTAGGG)n run were first detected at chromosome ends of the majority of living organisms, hence the name telomeric DNA repeats. Subsequently, it has become clear that telomeric motifs are also present within chromosomes, and they were suitably called interstitial telomeric sequences (ITSs). It is well known that telomeric DNA repeats play a key role in chromosome stability, preventing end-to-end fusions and precluding the recurrent DNA loss during replication. Recent data suggest that ITSs are also important genomic elements as they confer its karyotype plasticity. In fact, ITSs appeared to be among the most unstable microsatellite sequences as they are highly length polymorphic and can trigger chromosomal fragility and gross chromosomal rearrangements. Importantly, mechanisms responsible for their instability appear to be similar to the mechanisms that maintain the length of genuine telomeres. This review compares the mechanisms of maintenance and dynamic properties of telomeric repeats and ITSs and discusses the implications of these dynamics on genome stability.

ERK-mediated TIMELESS expression suppresses G2/M arrest in colon cancer cells

The cell cycle is under circadian regulation. Oncogenes can dysregulate circadian-regulated genes to disrupt the cell cycle, promoting tumor cell proliferation. As a regulator of G2/M arrest in response to DNA damage, the circadian gene Timeless Circadian Clock (TIMELESS) coordinates this connection and is a potential locus for oncogenic manipulation. TIMELESS expression was evaluated using RNASeq data from TCGA and by RT-qPCR and western blot analysis in a panel of colon cancer cell lines. TIMELESS expression following ERK inhibition was examined via western blot. Cell metabolic capacity, propidium iodide, and CFSE staining were used to evaluate the effect of TIMELESS depletion on colon cancer cell survival and proliferation. Cell metabolic capacity following TIMELESS depletion in combination with Wee1 or CHK1 inhibition was assessed. TIMELESS is overexpressed in cancer and required for increased cancer cell proliferation. ERK activation promotes TIMELESS expression. TIMELESS depletion increases γH2AX, a marker of DNA damage, and triggers G2/M arrest via increased CHK1 and CDK1 phosphorylation. TIMELESS depletion in combination with Wee1 or CHK1 inhibition causes an additive decrease in cancer cell metabolic capacity with limited effects in non-transformed human colon epithelial cells. The data show that ERK activation contributes to the overexpression of TIMELESS in cancer. Depletion of TIMELESS increases γH2AX and causes G2/M arrest, limiting cell proliferation. These results demonstrate a role for TIMELESS in cancer and encourage further examination of the link between circadian rhythm dysregulation and cancer cell proliferation.

Clock gene expression and locomotor activity predict death in the last days of life in Drosophila melanogaster

The importance of the circadian clock for the regulation of behaviour and physiology, and the molecular control of these rhythms by a set of clock genes are well defined. The circadian clock deteriorates with advancing age but the mechanism underlying is unclear. Here we recorded the expression of two key clock genes in young, middle-aged and old Drosophila using transgenic luciferase lines reporting period and timeless in vivo. We report a novel marker of imminent death in the expression of TIMELESS. In the days immediately preceding death TIMELESS expression increased to at least 150% of previous acrophase values (88.0% of n = 217) and lost circadian rhythmicity, which predicted death equally well in flies of different ages and under light and temperature cycles. We suggest this transient aberrant clock-gene expression is central to the mechanism of the disturbance in circadian behaviour before death (82.7% of n = 342). We also find that PERIOD expression in central-clock neurons remained robust with age, however PERIOD and TIMELESS in peripheral clocks showed a reduction in both expression level and rhythmicity. In conclusion, as flies age the molecular clock gradually declines at the peripheral level but continues to function at the central until days before death.

TIMELESS confers cisplatin resistance in nasopharyngeal carcinoma by activating the Wnt/β-catenin signaling pathway and promoting the epithelial mesenchymal transition

This study investigated the expression, clinicopathological significance and mechanism of action of TIMELESS, a mammalian homolog of a Drosophila circadian rhythm gene, in nasopharyngeal carcinoma. Quantitative real-time PCR, western blotting and immunohistochemistry revealed TIMELESS was upregulated in NPC cell lines (n = 8 vs. NP69 cells), and freshly-frozen (n = 6) and paraffin-embedded human NPC specimens (n = 108 vs. normal samples/non-tumor cells). TIMELESS expression was associated with T category (P = 0.002), N category (P = 0.001), clinical stage (P < 0.001), metastasis (P = 0.047), vital status (P = 0.013) and serum Epstein-Barr DNA (P = 0.005). High TIMELESS expression was associated with poorer overall survival (80.7% vs. 95.9%; P = 0.004) and progression free survival (68.1% vs. 88.0%; P = 0.005). Univariate and multivariate analysis revealed TIMELESS was an independent prognostic factor for overall survival and progression free survival. Stable ectopic overexpression of TIMELESS in NPC cell lines conferred resistance to cisplatin-induced apoptosis in vitro and in vivo, promoted an epithelial-to-mesenchymal transition phenotype, and activated the Wnt/β-catenin pathway and downstream gene transcription; knockdown of TIMELESS had the opposite effects. TIMELESS may play a role in the development of NPC and could represent a valuable prognostic factor and potential therapeutic target.