Cancer stem cell generation during epithelial-mesenchymal transition is temporally gated by intrinsic circadian clocks

Circadian rhythms in stem cells and their therapeutic potential

Circadian rhythms are present in almost all cells, but their existence in stem cells has remains not well established. Circadian clock appears to be closely associated with differentiated mature cells and rarely detected in immature embryonic stem cells. Recent evidence reveals the presence of circadian genes and rhythmic physiologic activities in stem cells as well as stem cell-derived extracellular vesicle (EV) characteristics. The circadian clock entails diverse physiologic and pathological mechanisms underlying cell fate. Integration of circadian rhythm to clinical applications, such as chronotherapy, chrono-biomarker, and environment modification, may facilitate therapeutic outcomes of stem cell-based regenerative medicine. Understanding circadian rhythms in stem cells can optimize stem cell-based therapies by determining the best times for harvesting and administering stem cells, thereby enhancing therapeutic efficacy. Further research into the circadian properties of stem cells will refine stem cell-based therapies, contributing to advancements in regenerative medicine.

Long non-coding RNA involved in the carcinogenesis of human female cancer - a comprehensive review

Recent years have seen an increase in our understanding of lncRNA and their role in various disease states. lncRNA molecules have been shown to contribute to carcinogenesis and influence the various cancer hallmarks and signalling pathways. It is pertinent to understand the specific contributions and mechanisms of action of these molecules in various cancers. This review provides an overview of the various lncRNA entities that influence and regulate the gynaecological cancers, namely, cervical, breast, ovarian and uterine cancers. The review curates a list of the key players and their effect on cellular processes. lncRNA molecules show immense potential to be used as diagnostic and prognostic indicators and in therapeutic strategies. Several phytochemicals, small molecules, RNA-based regulators, oligos and gene editing tools show promise as a therapeutic strategy. While this review highlights the promising developments in this field, it also underscores the necessity for further research to delineate the complex role of lncRNAs in cancer.

Update on the roles of regular daily rhythms in combating brain tumors

An endogenous time-keeping system found in all kingdoms of life, the endogenous circadian clock, is the source of the essential cyclic change mechanism known as the circadian rhythm. The primary circadian clock that synchronizes peripheral circadian clocks to the proper phase is housed in the anterior hypothalamus's suprachiasmatic nuclei (SCN), which functions as a central pacemaker. According to many epidemiological studies, many cancer types, especially brain tumors, have shown evidence of dysregulated clock gene expression, and the connection between clock and brain tumors is highly specific. In some studies, it is reported that the treatment administered in the morning has been linked to prolonged survival for brain cancer patients, and drug sensitivity and gene expression in gliomas follow daily rhythms. These results suggest a relationship between the circadian rhythm and the onset and spread of brain tumors, while further accumulation of research evidence will be needed to establish definitely these positive outcomes as well as to determine the mechanism underlying them. Chronotherapy provides a means of harnessing current medicines to prolong patients' lifespans and improve their quality of life, indicating the significance of circadian rhythm in enhancing the design of future patient care and clinical trials. Moreover, it is implicated that chronobiological therapy target may provide a significant challenge that warrants extensive effort to achieve. This review examines evidence of the relationship of circadian rhythm with glioma molecular pathogenesis and summarizes the mechanisms and drugs implicated in this disease.

Can we utilise the circadian clock to target cancer stem cells?

The 24-hourly circadian clock has been implicated in the regulation of multiple cancer hallmarks and characteristics. Cancer stem cells (CSCs) are a small but significant population of cells within many cancers, characterised by their self-renewal and clonogenic capacities. Increasing evidence points to CSCs having prominent roles in metastasis and drug resistance. However, it remains largely unknown how circadian clocks are involved with CSCs and what implications these interactions have for cancer progression and therapeutics. In this review, we examine the growing evidence on the role of circadian clocks in CSCs and discuss the potential therapeutic implications. This opens up new opportunities to target CSCs through various chronotherapeutic approaches, potentially improving clinical cancer outcomes. We propose different scenarios in which targeting circadian clocks in CSCs or their surrounding microenvironment could be developed into effective therapeutic strategies, including: (1) direct pharmacological targeting of core clock molecules, (2) optimising the timing of systemic anticancer therapies, and (3) targeting the neighbouring cells or systemic factors that influence tumour cells in a circadian-dependent manner.

Deciphering the topological landscape of glioma using a network theory framework

Glioma stem cells have been recognized as key players in glioma recurrence and therapeutic resistance, presenting a promising target for novel treatments. However, the limited understanding of the role glioma stem cells play in the glioma hierarchy has drawn controversy and hindered research translation into therapies. Despite significant advances in our understanding of gene regulatory networks, the dynamics of these networks and their implications for glioma remain elusive. This study employs a systemic theoretical perspective to integrate experimental knowledge into a core endogenous network model for glioma, thereby elucidating its energy landscape through network dynamics computation. The model identifies two stable states corresponding to astrocytic-like and oligodendrocytic-like tumor cells, connected by a transition state with the feature of high stemness, which serves as one of the energy barriers between astrocytic-like and oligodendrocytic-like states, indicating the instability of glioma stem cells in vivo. We also obtained various stable states further supporting glioma's multicellular origins and uncovered a group of transition states that could potentially induce tumor heterogeneity and therapeutic resistance. This research proposes that the transition states linking both glioma stable states are central to glioma heterogeneity and therapy resistance. Our approach may contribute to the advancement of glioma therapy by offering a novel perspective on the complex landscape of glioma biology.

Circadian disruption in cancer hallmarks: Novel insight into the molecular mechanisms of tumorigenesis and cancer treatment

Circadian rhythms are 24-h rhythms governing temporal organization of behavior and physiology generated by molecular clocks composed of autoregulatory transcription-translation feedback loops (TTFLs). Disruption of circadian rhythms leads to a spectrum of pathologies, including cancer by triggering or being involved in different hallmarks. Clock control of phenotypic plasticity involved in tumorigenesis operates in aberrant dedifferentiating to progenitor-like cell states, generation of cancer stem cells (CSCs) and epithelial-to-mesenchymal transition (EMT) events. Circadian rhythms might act as candidates for regulatory mechanisms of cellular senescent and functional determinants of senescence-associated secretory phenotype (SASP). Reciprocal control between clock and epigenetics sheds light on post-transcriptional regulation of circadian rhythms and opens avenues for novel anti-cancer strategies. Additionally, disrupting circadian rhythms influences microbiota communities that could be associated with altered homeostasis contributing to cancer development. Herein, we summarize recent advances in support of the nexus between disruptions of circadian rhythms and cancer hallmarks of new dimensions, thus providing novel perspectives on potentially effective treatment approaches for cancer management.

Biological clock regulation by the PER gene family: a new perspective on tumor development

The Period (PER) gene family is one of the core components of the circadian clock, with substantial correlations between the PER genes and cancers identified in extensive researches. Abnormal mutations in PER genes can influence cell function, metabolic activity, immunity, and therapy responses, thereby promoting the initiation and development of cancers. This ultimately results in unequal cancers progression and prognosis in patients. This leads to variable cancer progression and prognosis among patients. In-depth studies on the interactions between the PER genes and cancers can reveal novel strategies for cancer detection and treatment. In this review, we aim to provide a comprehensive overview of the latest research on the role of the PER gene family in cancer.

Molecular mechanisms of tumour development in glioblastoma: an emerging role for the circadian clock

Glioblastoma is one of the most lethal cancers with current therapeutic options lacking major successes. This underlines the necessity to understand glioblastoma biology on other levels and use these learnings for the development of new therapeutic concepts. Mounting evidence in the field of circadian medicine points to a tight interplay between disturbances of the circadian system and glioblastoma progression. The circadian clock, an internal biological mechanism governing numerous physiological processes across a 24-h cycle, also plays a pivotal role in regulationg key cellular functions, including DNA repair, cell cycle progression, and apoptosis. These processes are integral to tumour development and response to therapy. Disruptions in circadian rhythms can influence tumour growth, invasion, and response to treatment in glioblastoma patients. In this review, we explore the robust association between the circadian clock, and cancer hallmarks within the context of glioblastoma. We further discuss the impact of the circadian clock on eight cancer hallmarks shown previously to link the molecular clock to different cancers, and summarize the putative role of clock proteins in circadian rhythm disturbances and chronotherapy in glioblastoma. By unravelling the molecular mechanisms behind the intricate connections between the circadian clock and glioblastoma progression, researchers can pave the way for the identification of potential therapeutic targets, the development of innovative treatment strategies and personalized medicine approaches. In conclusion, this review underscores the significant influence of the circadian clock on the advancement and understanding of future therapies in glioblastoma, ultimately leading to enhanced outcomes for glioblastoma patients.

Tumor circadian clock strength influences metastatic potential and predicts patient prognosis in luminal A breast cancer

Studies in shift workers and model organisms link circadian disruption to breast cancer. However, molecular circadian rhythms in noncancerous and cancerous human breast tissues and their clinical relevance are largely unknown. We reconstructed rhythms informatically, integrating locally collected, time-stamped biopsies with public datasets. For noncancerous breast tissue, inflammatory, epithelial-mesenchymal transition (EMT), and estrogen responsiveness pathways show circadian modulation. Among tumors, clock correlation analysis demonstrates subtype-specific changes in circadian organization. Luminal A organoids and informatic ordering of luminal A samples exhibit continued, albeit dampened and reprogrammed rhythms. However, CYCLOPS magnitude, a measure of global rhythm strength, varied widely among luminal A samples. Cycling of EMT pathway genes was markedly increased in high-magnitude luminal A tumors. Surprisingly, patients with high-magnitude tumors had reduced 5-y survival. Correspondingly, 3D luminal A cultures show reduced invasion following molecular clock disruption. This study links subtype-specific circadian disruption in breast cancer to EMT, metastatic potential, and prognosis.

Circadian rhythm-based cancer therapy in randomised clinical trials

INTRODUCTION

Since the 2017 Nobel Prize awarded to J. Hall, M. Rosbash and M.W. Young for their discoveries of molecular mechanisms behind the biological clock, circadian rhythm-based therapy, also known as chronotherapy, is receiving more attention in oncology and the number of anatomical sites of interest in this field is increasing. This observation is in line with the clinical evidence provided by trials on head and neck, lung, colorectal and cervical cancers, as well as the presently ongoing chronotherapy trials for breast and brain cancers.

AREAS COVERED

The aim of this review was to collate all randomized trials conducted on chronotherapy for various tumor sites and to appraise the evidence for chrono-oncology to advance personalized therapy. Relevant literature was collected from Pubmed/Medline databases and from clinicatrials.gov.

EXPERT OPINION

Current randomized clinical trials offer a certain level of evidence for the potential of chronotherapy to personalize oncologic treatment. However, comparison of trial results is hindered by the differences in timing of radiation/chemotherapy, the absence of harmonized recommendations for treatment outcome evaluation and not ultimately, the general lack of considering gender as a matched variable in trials, which was found to be a powerful factor influencing response to treatment.

E-box binding transcription factors in cancer

E-boxes are important regulatory elements in the eukaryotic genome. Transcription factors can bind to E-boxes through their basic helix-loop-helix or zinc finger domain to regulate gene transcription. E-box-binding transcription factors (EBTFs) are important regulators of development and essential for physiological activities of the cell. The fundamental role of EBTFs in cancer has been highlighted by studies on the canonical oncogene MYC, yet many EBTFs exhibit common features, implying the existence of shared molecular principles of how they are involved in tumorigenesis. A comprehensive analysis of TFs that share the basic function of binding to E-boxes has been lacking. Here, we review the structure of EBTFs, their common features in regulating transcription, their physiological functions, and their mutual regulation. We also discuss their converging functions in cancer biology, their potential to be targeted as a regulatory network, and recent progress in drug development targeting these factors in cancer therapy.

Subtype-specific circadian clock dysregulation modulates breast cancer biology, invasiveness, and prognosis

Studies in shift workers and model organisms link circadian disruption to breast cancer. However, molecular rhythms in non-cancerous and cancerous human breast tissues are largely unknown. We reconstructed rhythms informatically, integrating locally collected, time-stamped biopsies with public datasets. For non-cancerous tissue, the inferred order of core-circadian genes matches established physiology. Inflammatory, epithelial-mesenchymal transition (EMT), and estrogen responsiveness pathways show circadian modulation. Among tumors, clock correlation analysis demonstrates subtype-specific changes in circadian organization. Luminal A organoids and informatic ordering of Luminal A samples exhibit continued, albeit disrupted rhythms. However, CYCLOPS magnitude, a measure of global rhythm strength, varied widely among Luminal A samples. Cycling of EMT pathway genes was markedly increased in high-magnitude Luminal A tumors. Patients with high-magnitude tumors had reduced 5-year survival. Correspondingly, 3D Luminal A cultures show reduced invasion following molecular clock disruption. This study links subtype-specific circadian disruption in breast cancer to EMT, metastatic potential, and prognosis.

Interactions of circadian clock genes with the hallmarks of cancer

The molecular machinery of the circadian clock regulates the expression of many genes and processes in the organism, allowing the adaptation of cellular activities to the daily light-dark cycles. Disruption of the circadian rhythm can lead to various pathologies, including cancer. Thus, disturbance of the normal circadian clock at both genetic and environmental levels has been described as an independent risk factor for cancer. In addition, researchers have proposed that circadian genes may have a tissue-dependent and/or context-dependent role in tumorigenesis and may function both as tumor suppressors and oncogenes. Finally, circadian clock core genes may trigger or at least be involved in different hallmarks of cancer. Hence, expanding the knowledge of the molecular basis of the circadian clock would be helpful to identify new prognostic markers of tumorigenesis and potential therapeutic targets.

Potential Role of the Circadian Clock in the Regulation of Cancer Stem Cells and Cancer Therapy

Circadian rhythms, including sleep/wake cycles as well as hormonal, immune, metabolic, and cell proliferation rhythms, are fundamental biological processes driven by a cellular time-keeping system called the circadian clock. Disruptions in these rhythms due to genetic alterations or irregular lifestyles cause fundamental changes in physiology, from metabolism to cellular proliferation and differentiation, resulting in pathological consequences including cancer. Cancer cells are not uniform and static but exist as different subtypes with phenotypic and functional differences in the tumor microenvironment. At the top of the heterogeneous tumor cell hierarchy, cancer stem cells (CSCs), a self-renewing and multi-potent cancer cell type, are most responsible for tumor recurrence and metastasis, chemoresistance, and mortality. Phenotypically, CSCs are associated with the epithelial-mesenchymal transition (EMT), which confers cancer cells with increased motility and invasion ability that is characteristic of malignant and drug-resistant stem cells. Recently, emerging studies of different cancer types, such as glioblastoma, leukemia, prostate cancer, and breast cancer, suggest that the circadian clock plays an important role in the maintenance of CSC/EMT characteristics. In this review, we describe recent discoveries regarding how tumor intrinsic and extrinsic circadian clock-regulating factors affect CSC evolution, highlighting the possibility of developing novel chronotherapeutic strategies that could be used against CSCs to fight cancer.

Developments on tumour site-specific chrono-oncology towards personalised treatment

Research into chronotherapy has seen notable developments over the past decades, with a clear focus on the identification of circadian clock genes as potential treatment targets. Moreover, new factors are investigated, such as gender and the role of cancer stem cells in influencing the outcome of chronomodulated treatments. These factors could add to the arsenal of parameters that assist with patient stratification and treatment personalisation. Literature analysis showed that certain anatomical sites received more attention and the associated studies reported clinically significant results, even though some findings are contradictory. The aim of this work was to review the existing studies on chrono-oncology using a tumour site-specific approach and to highlight the status of research in various cancers. Inconsistencies in data reporting, the nature of the studies and the highly heterogeneous patient characteristics, highlight the need for well-designed randomised controlled trials to elucidate the real potential of chronotherapy in oncology.

Exploring glioblastoma stem cell heterogeneity: Immune microenvironment modulation and therapeutic opportunities

Despite its growing use in cancer treatment, immunotherapy has been virtually ineffective in clinical trials for gliomas. The inherently cold tumor immune microenvironment (TIME) in gliomas, characterized by a high ratio of pro-tumor to anti-tumor immune cell infiltrates, acts as a seemingly insurmountable barrier to immunotherapy. Glioma stem cells (GSCs) within these tumors are key contributors to this cold TIME, often functioning indirectly through activation and recruitment of pro-tumor immune cell types. Furthermore, drivers of GSC plasticity and heterogeneity (e.g., reprogramming transcription factors, epigenetic modifications) are associated with induction of immunosuppressive cell states. Recent studies have identified GSC-intrinsic mechanisms, including functional mimicry of immune suppressive cell types, as key determinants of anti-tumor immune escape. In this review, we cover recent advancements in our understanding of GSC-intrinsic mechanisms that modulate GSC-TIME interactions and discuss cutting-edge techniques and bioinformatics platforms available to study immune modulation at high cellular resolution with exploration of both malignant (i.e., GSC) and non-malignant (i.e., immune) cell fractions. Finally, we provide insight into the therapeutic opportunities for targeting immunomodulatory GSC-intrinsic mechanisms to potentiate immunotherapy response in gliomas.

Insights about circadian clock in glioma: From molecular pathways to therapeutic drugs

Glioma is characterized as the most aggressive brain tumor that occurred in the central nervous system. The circadian rhythm is an essential cyclic change system generated by the endogenous circadian clock. Current studies found that the circadian clock affects glioma pathophysiology. It is still controversial whether the circadian rhythm disruption is a cause or an effect of tumorigenesis. This review discussed the association between cell cycle and circadian clock and provided a prominent molecular theoretical basis for tumor therapy. We illustrated the external factors affecting the circadian clock including thermodynamics, hypoxia, post-translation, and microRNA, while the internal characteristics concerning the circadian clock in glioma involve stemness, metabolism, radiotherapy sensitivity, and chemotherapy sensitivity. We also summarized the molecular pathways and the therapeutic drugs involved in the glioma circadian rhythm. There are still many questions in this field waiting for further investigation. The results of glioma chronotherapy in sensitizing radiation therapy and chemotherapy have shown great therapeutic potential in improving clinical outcomes. These findings will help us further understand the characteristics of glioma pathophysiology.

Stress-induced epinephrine promotes epithelial-to-mesenchymal transition and stemness of CRC through the CEBPB/TRIM2/P53 axis

Background

Previous studies have indicated that chronic emotional stressors likely participate in the occurrence of cancers. However, direct evidence connecting stress and colorectal cancer development remains almost completely unexplored.

Methods

Chronic stress mouse model was used to investigate the influence of stress on tumorigenesis. Several major agonists and antagonists of adrenergic receptors were applied to investigate the effects of β-adrenergic signaling on the development of CRC. Chromatin immunoprecipitation assays (CHIP) were used to investigate the binding of p53 and CEBPB to TRIM2 promoter. Mammosphere cultures, Cell Counting Kit-8 (CCK-8) assay, colony-formation assay, scratch wound healing assays, qPCR, immunofluorescence, coimmunoprecipitation and western blotting were used to explore the effect of stress-induced epinephrine on the CEBPB/TRIM2/P53 axis and the progress of CRC cells.

Results

In this study, we found that stress-induced epinephrine (EPI) promotes the proliferation, metastasis and CSC generation of CRC primarily through the β2-adrenergic receptor. Furthermore, our studies also confirmed that chronic stress decreased the stability of p53 protein by promoting p53 ubiquitination. Results of transcriptome sequencing indicated that TRIM2 was overexpressed in cells treated with EPI. Further studies indicated that TRIM2 could regulate the stability of p53 protein by promoting p53 ubiquitination. Finally, we further proved that CEBPB was regulated by EPI and acts as the upstream transcription factor of TRIM2.

Conclusions

Our studies proved that stress-induced EPI promotes the development and stemness of CRC through the CEBPB/TRIM2/P53 axis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12967-022-03467-8.

The Relevance of Circadian Clocks to Stem Cell Differentiation and Cancer Progression

The molecular mechanism of circadian clocks depends on transcription-translation feedback loops (TTFLs) that have known effects on key cellular processes. However, the distinct role of circadian TTFLs in mammalian stem cells and other less differentiated cells remains poorly understood. Neural stem cells (NSCs) of the brain generate neurons and glia postnatally but also may become cancer stem cells (CSCs), particularly in astrocytomas. Evidence indicates clock TTFL impairment is needed for tumor growth and progression; although, this issue has been examined primarily in more differentiated cancer cells rather than CSCs. Similarly, few studies have examined circadian rhythms in NSCs. After decades of research, it is now well recognized that tumors consist of CSCs and a range of other cancer cells along with noncancerous stromal cells. The circadian properties of these many contributors to tumor properties and treatment outcome are being widely explored. New molecular tools and ones in development will likely enable greater discrimination of important circadian and non-circadian cells within malignancies at multiple stages of cancer progression and following therapy. Here, we focus on adult NSCs and glioma CSCs to address how cells at different stages of differentiation may harbor unique states of the molecular circadian clock influencing differentiation and cell fate.

MDSCs might be "Achilles heel" for eradicating CSCs

During tumor initiation and progression, the complicated role of immune cells in the tumor immune microenvironment remains a concern. Myeloid-derived suppressor cells (MDSCs) are a group of immune cells that originate from the bone marrow and have immunosuppressive potency in various diseases, including cancer. In recent years, the key role of cancer stemness has received increasing attention in cancer development and therapy. Several studies have demonstrated the important regulatory relationship between MDSCs and cancer stem cells (CSCs). However, there is still no clear understanding regarding the complex interacting regulation of tumor malignancy, and current research progress is limited. In this review, we summarize the complicated role of MDSCs in the modulation of cancer stemness, evaluate the mechanism of the relationship between CSCs and MDSCs, and discuss potential strategies for eradicating CSCs with respect to MDSCs.

A Series of Furimazine Derivatives for Sustained Live-Cell Bioluminescence Imaging and Application to the Monitoring of Myogenesis at the Single-Cell Level

Bioluminescence (BL) imaging, which utilizes light emitted through the enzymatic reaction of luciferase oxidizing its substrate luciferin, enables sensitive and noninvasive monitoring of life phenomena. Herein, we developed a series of caged furimazine (FMZ) derivatives by introducing a protective group at the C-3 position and a hydroxy group at the C-6 phenyl ring to realize long-term live-cell BL imaging based on the NanoLuc (NLuc)/NanoKAZ (NKAZ)-FMZ system. The membrane permeability and cytotoxicity of the substrates were evaluated and related to their hydrophobicity. Among the series, the derivative with the bulkiest protective group (adamantanecarbonyl group) and a hydroxy substituent (named Ad-FMZ-OH) showed significantly prolonged and constant BL signal in cells expressing NLuc compared to the native FMZ substrate. This derivative enabled continuous BL imaging at the single-cell level for 24 h. Furthermore, we applied Ad-FMZ-OH to BL imaging of myocyte fusion and succeeded in the consecutive and sensitive monitoring at a single-cell level over a day. In summary, NLuc/NKAZ-caged FMZ derivatives have the potential to be applied to live-cell BL imaging of various life phenomena that require long-term observation.

The Circadian Gene NPAS2 Act as a Putative Tumor Stimulative Factor for Uterine Corpus Endometrial Carcinoma

Background

Mounting evidence indicates altered circadian rhythm represents a critical factor affecting carcinogenesis and tumor progression. The circadian gene neuronal PAS domain protein 2 (NPAS2) constitutes a newly discovered prognostic biomarker. NPAS2 dysregulation is found in multiple malignancies, although its functions in uterine corpus endometrial carcinoma (UCEC) remain largely unknown.

Objective

To evaluate NPAS2’s roles in UCEC and to explore the underlying mechanisms.

Methods

NPAS2 transcription levels, patient prognosis, different clinical stages and target microRNAs in UCEC cases were comparatively assessed based on public databases, including UALCAN, GEPIA, TIMER, Kaplan–Meier plotter, starBase database, LinkedOmics and String. Then, qRT-PCR and immunohistochemical analysis were applied to analyze the expression of NPAS2 in UCEC tissue samples. CCK-8, clonogenic assay and flow cytometry were carried out for detecting cell viability, colony formation ability and cell apoptosis, respectively.

Results

NPAS2 was upregulated in tissue samples from UCEC cases compared with the corresponding control specimens. NPAS2 overexpression was associated with decreased overall (OS), disease free (DFS) and relapse free (RFS) survival in UCEC. In addition, NPAS2 overexpression was associated with clinical stage, tumor grade, estrogen receptor status, myometrial invasion in UCEC. Furthermore, NPAS2 knockdown or overexpression altered cell proliferation and apoptosis in UCEC. Moreover, NPAS2 showed significant negative correlations with miR-17-5p and miR-93-5p, and positive correlations with miR-106a-5p and miR-381-3p in UCEC.

Conclusion

NPAS2 overexpression is associated with poor prognosis and clinicopathological characteristics in UCEC and promotes proliferation and colony formation while inhibiting apoptosis. Finally, NPAS2 is associated with several miRNAs in UCEC.

lncRNA and breast cancer: Progress from identifying mechanisms to challenges and opportunities of clinical treatment

Breast cancer is a malignant tumor that has a high mortality rate and mostly occurs in women. Although significant progress has been made in the implementation of personalized treatment strategies for molecular subtypes in breast cancer, the therapeutic response is often not satisfactory. Studies have reported that long non-coding RNAs (lncRNAs) are abnormally expressed in breast cancer and closely related to the occurrence and development of breast cancer. In addition, the high tissue and cell-type specificity makes lncRNAs particularly attractive as diagnostic biomarkers, prognostic factors, and specific therapeutic targets. Therefore, an in-depth understanding of the regulatory mechanisms of lncRNAs in breast cancer is essential for developing new treatment strategies. In this review, we systematically elucidate the general characteristics, potential mechanisms, and targeted therapy of lncRNAs and discuss the emerging functions of lncRNAs in breast cancer. Additionally, we also highlight the advantages and challenges of using lncRNAs as biomarkers for diagnosis or therapeutic targets for drug resistance in breast cancer and present future perspectives in clinical practice.

BMAL1 Knockdown Leans Epithelial-Mesenchymal Balance toward Epithelial Properties and Decreases the Chemoresistance of Colon Carcinoma Cells

The circadian clock coordinates biological and physiological functions to day/night cycles. The perturbation of the circadian clock increases cancer risk and affects cancer progression. Here, we studied how BMAL1 knockdown (BMAL1-KD) by shRNA affects the epithelial-mesenchymal transition (EMT), a critical early event in the invasion and metastasis of colorectal carcinoma (CRC). In corresponding to a gene set enrichment analysis, which showed a significant enrichment of EMT and invasive signatures in BMAL1_high CRC patients as compared to BMAL1_low CRC patients, our results revealed that BMAL1 is implicated in keeping the epithelial-mesenchymal equilibrium of CRC cells and influences their capacity of adhesion, migration, invasion, and chemoresistance. Firstly, BMAL1-KD increased the expression of epithelial markers (E-cadherin, CK-20, and EpCAM) but decreased the expression of Twist and mesenchymal markers (N-cadherin and vimentin) in CRC cell lines. Finally, the molecular alterations after BMAL1-KD promoted mesenchymal-to-epithelial transition-like changes mostly appeared in two primary CRC cell lines (i.e., HCT116 and SW480) compared to the metastatic cell line SW620. As a consequence, migration/invasion and drug resistance capacities decreased in HCT116 and SW480 BMAL1-KD cells. Together, BMAL1-KD alerts the delicate equilibrium between epithelial and mesenchymal properties of CRC cell lines, which revealed the crucial role of BMAL1 in EMT-related CRC metastasis and chemoresistance.

The role of the circadian clock in cancer hallmark acquisition and immune-based cancer therapeutics

The circadian system temporally regulates physiology to maintain homeostasis. Co-opting and disrupting circadian signals appear to be distinct attributes that are functionally important for the development of a tumor and can enable or give rise to the hallmarks that tumors use to facilitate their initiation, growth and progression. Because circadian signals are also strong regulators of immune cell proliferation, trafficking and exhaustion states, they play a role in how tumors respond to immune-based cancer therapeutics. While immuno-oncology has heralded a paradigm shift in cancer therapeutics, greater accuracy is needed to increase our capability of predicting who will respond favorably to, or who is likely to experience the troubling adverse effects of, immunotherapy. Insights into circadian signals may further refine our understanding of biological determinants of response and help answer the fundamental question of whether certain perturbations in circadian signals interfere with the activity of immune checkpoint inhibitors. Here we review the body of literature highlighting circadian disruption as a cancer promoter and synthesize the burgeoning evidence suggesting circadian signals play a role in how tumors respond to immune-based anti-cancer therapeutics. The goal is to develop a framework to advance our understanding of the relationships between circadian markers, cancer biology, and immunotherapeutics. Bolstered by this new understanding, these relationships may then be pursued in future clinical studies to improve our ability to predict which patients will respond favorably to, and avoid the adverse effects of, traditional and immune-based cancer therapeutics.