Signaling networks that link cell proliferation and cell fate

Therapeutic Efficacy of Quercetin and Its Nanoformulation Both the Mono- or Combination Therapies in the Management of Cancer: An Update with Molecular Mechanisms

Quercetin, a major representative of the flavonol subclass found abundantly in almost all edible vegetables and fruits, showed remarkable therapeutic properties and was beneficial in numerous degenerative diseases by preventing lipid peroxidation. Quercetin is beneficial in different diseases, such as atherosclerosis and chronic inflammation. This study aims to find out the anticancer activities of quercetin and to determine different mechanisms and pathways which are responsible for the anticancer effect. It also revealed the biopharmaceutical, toxicological characteristics, and clinical utilization of quercetin to evaluate its suitability for further investigations as a reliable anticancer drug. All of the relevant data concerning this compound with cancer was collected using different scientific search engines, including PubMed, Springer Link, Wiley Online, Web of Science, SciFinder, ScienceDirect, and Google Scholar. This review demonstrated that quercetin showed strong anticancer properties, including apoptosis, inhibition of cell proliferation, autophagy, cell cycle arrest, inhibition of angiogenesis, and inhibition of invasion and migration against various types of cancer. Findings also revealed that quercetin could significantly moderate and regulate different pathways, including PI3K/AKT-mTORC1 pathway, JAK/STAT signaling system, MAPK signaling pathway, MMP signaling pathway, NF-κB pathway, and p-Camk2/p-DRP1 pathway. However, this study found that quercetin showed poor oral bioavailability due to reduced absorption; this limitation is overcome by applying nanotechnology (nanoformulation of quercetin). Moreover, different investigations revealed that quercetin expressed no toxic effect in the investigated subjects. Based on the view of these findings, it is demonstrated that quercetin might be considered a reliable chemotherapeutic drug candidate in the treatment of different cancers. However, more clinical studies are suggested to establish the proper therapeutic efficacy, safety, and human dose.

Insight into mammary gland development and tumor progression in an E2F5 conditional knockout mouse model

Development of breast cancer is linked to altered regulation of mammary gland developmental processes. A better understanding of normal mammary gland development can thus reveal possible mechanisms of how normal cells are re-programmed to become malignant. E2Fs 1-4 are part of the E2F transcription factor family with varied roles in mammary development, but little is known about the role of E2F5. A combination of scRNAseq and predictive signature tools demonstrated the presence of E2F5 in the mammary gland and showed changes in predicted activity during the various phases of mammary gland development. Testing the hypothesis that E2F5 regulates mammary function, we generated a mammary-specific E2F5 knockout mouse model, resulting in modest mammary gland development changes. However, after a prolonged latency the E2F5 conditional knockout mice developed highly metastatic mammary tumors. Whole genome sequencing revealed significant intertumor heterogeneity. RNAseq and protein analysis identified altered levels of Cyclin D1, with similarities to MMTV-Neu tumors, suggesting that E2F5 conditional knockout mammary glands and tumors may be dependent on Cyclin D1. Transplantation of the tumors revealed metastases to lymph nodes that were enriched through serial transplantation in immune competent recipients. Based on these findings, we propose that loss of E2F5 leads to altered regulation of Cyclin D1, which facilitates the development of metastatic mammary tumors after long latency. More importantly, this study demonstrates that conditional loss of E2F5 in the mammary gland leads to tumor formation, revealing its role as a transcription factor regulating a network of genes that normally result in a tumor suppressor function.

From Crypts to Cancer: A Holistic Perspective on Colorectal Carcinogenesis and Therapeutic Strategies

Colorectal cancer (CRC) represents a significant global health burden, with high incidence and mortality rates worldwide. Recent progress in research highlights the distinct clinical and molecular characteristics of colon versus rectal cancers, underscoring tumor location's importance in treatment approaches. This article provides a comprehensive review of our current understanding of CRC epidemiology, risk factors, molecular pathogenesis, and management strategies. We also present the intricate cellular architecture of colonic crypts and their roles in intestinal homeostasis. Colorectal carcinogenesis multistep processes are also described, covering the conventional adenoma-carcinoma sequence, alternative serrated pathways, and the influential Vogelstein model, which proposes sequential APC, KRAS, and TP53 alterations as drivers. The consensus molecular CRC subtypes (CMS1-CMS4) are examined, shedding light on disease heterogeneity and personalized therapy implications.

Network topology and interaction logic determine states it supports

In this review paper we summarize a recent progress on the problem of describing range of dynamics supported by a network. We show that there is natural connection between network models consisting of collections of multivalued monotone boolean functions and ordinary differential equations models. We show how to construct such collections and use them to answer questions about prevalence of cellular phenotypes that correspond to equilibria of network models.

Quiescence-Origin Senescence: A New Paradigm in Cellular Aging

Cellular senescence, traditionally viewed as a consequence of proliferating and growing cells overwhelmed by extensive stresses and damage, has long been recognized as a critical cellular aging mechanism. Recent research, however, has revealed a novel pathway termed "quiescence-origin senescence", where cells directly transition into senescence from the quiescent state, bypassing cell proliferation and growth. This opinion paper presents a framework conceptualizing a continuum between quiescence and senescence with quiescence deepening as a precursor to senescence entry. We explore the triggers and controllers of this process and discuss its biological implications. Given that the majority of cells in the human body are dormant rather than proliferative, understanding quiescence-origin senescence has significant implications for tissue homeostasis, aging, cancer, and various disease processes. The new paradigm in exploring this previously overlooked senescent cell population may reshape our intervention strategies for age-related diseases and tissue regeneration.

Tirbanibulin decreases cell proliferation and downregulates protein expression of oncogenic pathways in human papillomavirus containing HeLa cells

Tirbanibulin 1% ointment is a synthetic antiproliferative agent approved in 2021 by the European Union for treating actinic keratoses (AK). Topical tirbanibulin has clinically resolved HPV-57 ( +) squamous cell carcinoma (SCC), HPV-16 ( +) vulvar high-grade squamous intraepithelial lesion, epidermodysplasia verruciformis, and condyloma. We examined how tirbanibulin might affect HPV oncoprotein expression and affect other cellular pathways involved in cell proliferation and transformation. We treated the HeLa cell line, containing integrated HPV-18, with increasing doses of tirbanibulin to determine the effects on cell proliferation. Immunoblotting was performed with antibodies against the Src canonical pathway, HPV 18 E6 and E7 transcription regulation, apoptosis, and invasion and metastasis pathways. Cell proliferation assays with tirbanibulin determined the half-maximal inhibitory concentration (IC50) of HeLa cells to be 31.49 nmol/L. Increasing concentrations of tirbanibulin downregulates the protein expression of Src (p < 0.001), phospho-Src (p < 0.001), Ras (p < 0.01), c-Raf (p < 0.001), ERK1 (p < 0.001), phospho-ERK1 (p < 0.001), phospho-ERK2 (p < 0.01), phospho-Mnk1 (p < 0.001), eIF4E (p < 0.01), phospho-eIF4E (p < 0.001), E6 (p < 0.01), E7 (p < 0.01), Rb (p < 0.01), phospho-Rb (p < 0.001), MDM2 (p < 0.01), E2F1 (p < 0.001), phospho-FAK (p < 0.001), phospho-p130 Cas (p < 0.001), Mcl-1 (p < 0.01), and Bcl-2 (p < 0.001), but upregulates cPARP (p < 0.001), and cPARP/fPARP (p < 0.001). These results demonstrate that tirbanibulin may impact expression of HPV oncoproteins via the Src- MEK- pathway. Tirbanibulin significantly downregulates oncogenic proteins related to cell cycle regulation and cell proliferation while upregulating apoptosis pathways.

Multimodal Therapy Approaches for NUT Carcinoma by Dual Combination of Oncolytic Virus Talimogene Laherparepvec with Small Molecule Inhibitors

NUT (nuclear-protein-in-testis) carcinoma (NC) is a highly aggressive tumor disease. Given that current treatment regimens offer a median survival of six months only, it is likely that this type of tumor requires an extended multimodal treatment approach to improve prognosis. In an earlier case report, we could show that an oncolytic herpes simplex virus (T-VEC) is functional in NC patients. To identify further combination partners for T-VEC, we have investigated the anti-tumoral effects of T-VEC and five different small molecule inhibitors (SMIs) alone and in combination in human NC cell lines. Dual combinations were found to result in higher rates of tumor cell reductions when compared to the respective monotherapy as demonstrated by viability assays and real-time tumor cell growth monitoring. Interestingly, we found that the combination of T-VEC with SMIs resulted in both stronger and earlier reductions in the expression of c-Myc, a main driver of NC cell proliferation, when compared to T-VEC monotherapy. These results indicate the great potential of combinatorial therapies using oncolytic viruses and SMIs to control the highly aggressive behavior of NC cancers and probably will pave the way for innovative multimodal clinical studies in the near future.

Interplay between zinc and cell proliferation and implications for the growth of livestock

Zinc (Zn) plays a critical role in the growth of livestock, which depends on cell proliferation. In addition to modifying the growth associated with its effects on food intake, mitogenic hormones, signal transduction and gene transcription, Zn also regulates body weight gain through mediating cell proliferation. Zn deficiency in animals leads to growth inhibition, along with an arrest of cell cycle progression at G0/G1 and S phase due to depression in the expression of cyclin D/E and DNA synthesis. Therefore, in the present study, the interplay between Zn and cell proliferation and implications for the growth of livestock were reviewed, in which Zn regulates cell proliferation in several ways, especially cell cycle progression at the G0/G1 phase DNA synthesis and mitosis. During the cell cycle, the Zn transporters and major Zn binding proteins such as metallothioneins are altered with the requirements of cellular Zn level and nuclear translocation of Zn. In addition, calcium signaling, MAPK pathway and PI3K/Akt cascades are also involved in the process of Zn-interfering cell proliferation. The evidence collected over the last decade highlights the necessity of Zn for normal cell proliferation, which suggests Zn supplementation should be considered for the growth and health of poultry.

High-Intensity Focused Ultrasound Increases Collagen and Elastin Fiber Synthesis by Modulating Caveolin-1 in Aging Skin

Caveolin-1 (Cav-1) induces cellular senescence by reducing extracellular signal-regulated kinase (ERK)1/2 phosphorylation and activating p53 via inhibition of mouse double minute 2 homolog (MDM2) and sirtuin 1 (Sirt1), promoting cell cycle arrest and decreasing fibroblast proliferation and collagen synthesis. High-intensity focused ultrasound (HIFU) treatment increases collagen synthesis, rejuvenating skin. Using H2O2-induced senescent fibroblasts and the skin of 12-month-old mice, we tested the hypothesis that HIFU increases collagen production through Cav-1 modulation. HIFU was administered at 0.3, 0.5, or 0.7 J in the LINEAR and DOT modes. In both models, HIFU administration decreased Cav-1 levels, increased ERK1/2 phosphorylation, and decreased the binding of Cav-1 with both MDM2 and Sirt1. HIFU administration decreased p53 activation (acetylated p53) and p21 levels and increased cyclin D1, cyclin-dependent kinase 2, and proliferating cell nuclear antigen levels in both models. HIFU treatment increased collagen and elastin expression, collagen fiber accumulation, and elastin fiber density in aging skin, with 0.5 J in LINEAR mode resulting in the most prominent effects. HIFU treatment increased collagen synthesis to levels similar to those in Cav-1-silenced senescent fibroblasts. Our results suggest that HIFU administration increases dermal collagen and elastin fibers in aging skin via Cav-1 modulation and reduced p53 activity.

Rice Germ Attenuates Chronic Unpredictable Mild Stress-Induced Muscle Atrophy

Chronic stress leads to hypothalamic-pituitary-adrenal axis dysfunction, increasing cortisol levels. Glucocorticoids (GCs) promote muscle degradation and inhibit muscle synthesis, eventually causing muscle atrophy. In this study, we aimed to evaluate whether rice germ supplemented with 30% γ-aminobutyric acid (RG) attenuates muscle atrophy in an animal model of chronic unpredictable mild stress (CUMS). We observed that CUMS raised the adrenal gland weight and serum adrenocorticotropic hormone (ACTH) and cortisol levels, and these effects were reversed by RG. CUMS also enhanced the expression of the GC receptor (GR) and GC-GR binding in the gastrocnemius muscle, which were attenuated by RG. The expression levels of muscle degradation-related signaling pathways, such as the Klf15, Redd-1, FoxO3a, Atrogin-1, and MuRF1 pathways, were enhanced by CUMS and attenuated by RG. Muscle synthesis-related signaling pathways, such as the IGF-1/AKT/mTOR/s6k/4E-BP1 pathway, were reduced by CUMS and enhanced by RG. Moreover, CUMS raised oxidative stress by enhancing the levels of iNOS and acetylated p53, which are involved in cell cycle arrest, whereas RG attenuated both iNOS and acetylated p53 levels. Cell proliferation in the gastrocnemius muscle was reduced by CUMS and enhanced by RG. The muscle weight, muscle fiber cross-sectional area, and grip strength were reduced by CUMS and enhanced by RG. Therefore, RG attenuated ACTH levels and cortisol-related muscle atrophy in CUMS animals.

Design principles of improving the dose-response alignment in coupled GTPase switches

"Dose-response alignment" (DoRA), where the downstream response of cellular signaling pathways closely matches the fraction of activated receptor, can improve the fidelity of dose information transmission. The negative feedback has been experimentally identified as a key component for DoRA, but numerical simulations indicate that negative feedback is not sufficient to achieve perfect DoRA, i.e., perfect match of downstream response and receptor activation level. Thus a natural question is whether there exist design principles for signaling motifs within only negative feedback loops to improve DoRA to near-perfect DoRA. Here, we investigated several model formulations of an experimentally validated circuit that couples two molecular switches-mGTPase (monomeric GTPase) and tGTPase (heterotrimeric GTPases) - with negative feedback loops. In the absence of feedback, the low and intermediate mGTPase activation levels benefit DoRA in mass action and Hill-function models, respectively. Adding negative feedback has versatile roles on DoRA: it may impair DoRA in the mass action model with low mGTPase activation level and Hill-function model with intermediate mGTPase activation level; in other cases, i.e., the mass action model with a high mGTPase activation level or the Hill-function model with a non-intermediate mGTPase activation level, it improves DoRA. Furthermore, we found that DoRA in a longer cascade (i.e., tGTPase) can be obtained using Hill-function kinetics under certain conditions. In summary, we show how ranges of activity of mGTPase, reaction kinetics, the negative feedback, and the cascade length affect DoRA. This work provides a framework for improving the DoRA performance in signaling motifs with negative feedback.

Activated Src requires Cadherin-11, Rac, and gp130 for Stat3 activation and survival of mouse Balb/c3T3 fibroblasts

We previously demonstrated that engagement of cadherins, cell to cell adhesion molecules, triggers a dramatic increase in levels and activity of the Rac/Cdc42 small GTPases, which is followed by secretion of IL6 family cytokines and activation of their common receptor, gp130, in an autocrine manner. This results in phosphorylation of the Signal Transducer and Activator of Transcription-3 (Stat3) on tyrosine-705, which then dimerizes, migrates to the nucleus, and activates transcription of genes involved in cell division and survival. In the present report we demonstrate that, in mouse Balb/c3T3 fibroblasts, mutationally activated Src527F also increases Rac levels, leading to secretion of IL6 family cytokines and gp130 activation, which triggers the Stat3-ptyr705 increase. Interestingly, our results also demonstrate that cadherin-11 is required to preserve gp130 levels for IL6 family signaling. At the same time, however, activated Src527F downregulates cadherin-11, in a quantitative manner. As a result, Src527F expression to intermediate levels allows sufficient cadherin-11, hence gp130 levels for Stat3 activation, as expected. However, expressed to high levels, Src527F eliminates cadherin-11, hence gp130 signaling, thus abolishing Stat3-ptyr705 stimulation. Taken together, these data establish for the first time a loop between Src, cadherin-11, gp130, and Stat3 activation. This fine balance between Src527F and cadherin-11 levels which is required for Stat3 activation and cellular survival could have significant therapeutic implications.

Roads to Stat3 Paved with Cadherins

The engagement of cadherins, cell-to-cell adhesion proteins, triggers a dramatic increase in the levels and activity of the Rac/Cdc42 GTPases, through the inhibition of proteasomal degradation. This leads to an increase in transcription and secretion of IL6 family cytokines, activation of their common receptor, gp130, in an autocrine manner and phosphorylation of the signal transducer and activator of transcription-3 (Stat3) on tyrosine-705 by the Jak kinases. Stat3 subsequently dimerizes, migrates to the nucleus and activates the transcription of genes involved in cell division and survival. The Src oncogene also increases Rac levels, leading to secretion of IL6 family cytokines and gp130 activation, which triggers a Stat3-ptyr705 increase. Interestingly, at the same time, Src downregulates cadherins in a quantitative manner, while cadherins are required to preserve gp130 levels for IL6 family signalling. Therefore, a fine balance between Src527F/Rac/IL6 and Src527F/cadherin/gp130 levels is in existence, which is required for Stat3 activation. This further demonstrates the important role of cadherins in the activation of Stat3, through preservation of gp130 function. Conversely, the absence of cadherin engagement correlates with low Stat3 activity: In sparsely growing cells, both gp130 and Stat3-ptyr705 levels are very low, despite the fact that cSrc is active in the FAK (focal adhesion kinase)/cSrc complex, which further indicates that the engagement of cadherins is important for Stat3 activation, not just their presence. Furthermore, the caveolin-1 protein downregulates Stat3 through binding and sequestration of cadherins to the scaffolding domain of caveolin-1. We hypothesize that the cadherins/Rac/gp130 axis may be a conserved pathway to Stat3 activation in a number of systems. This fact could have significant implications in Stat3 biology, as well as in drug testing and development.

Inhibiting Cyclin-Dependent Kinase 6 by Taurine: Implications in Anticancer Therapeutics

Cyclin-dependent kinase 6 (CDK6) is linked with a cyclin partner and plays a crucial role in the early stages of cancer development. It is currently a potential drug target for developing therapeutic molecules targeting cancer therapy. Here, we have identified taurine as an inhibitor of CDK6 using combined in silico and experimental studies. We performed various experiments to find the binding affinity of taurine with CDK6. Molecular docking analysis revealed critical residues of CDK6 that are involved in taurine binding. Fluorescence measurement studies showed that taurine binds to CDK6 with a significant binding affinity, with a binding constant of K = 0.7 × 10⁷ M^-1 for the CDK6-taurine complex. Enzyme inhibition assay suggested taurine as a good inhibitor of CDK6 possessing an IC₅₀ value of 4.44 μM. Isothermal titration calorimetry analysis further confirmed a spontaneous binding of taurine with CDK6 and delineated the thermodynamic parameters for the CDK6-taurine system. Altogether, this study established taurine as a CDK6 inhibitor, providing a base for using taurine and its derivatives in CDK6-associated cancer and other diseases.

A Model for the Proliferation–Quiescence Transition in Human Cells

The process of revitalising quiescent cells in order for them to proliferate plays a pivotal role in the repair of worn-out tissues as well as for tissue homeostasis. This process is also crucial in the growth, development and well-being of higher multi-cellular organisms such as mammals. Deregulation of proliferation-quiescence transition is related to many diseases, such as cancer. Recent studies have revealed that this proliferation–quiescence process is regulated tightly by the Rb−E2F bistable switch mechanism. Based on experimental observations, in this study, we formulate a mathematical model to examine the effect of the growth factor concentration on the proliferation–quiescence transition in human cells. Working with a non-dimensionalised model, we prove the positivity, boundedness and uniqueness of solutions. To understand model solution behaviour close to bifurcation points, we carry out bifurcation analysis, which is further illustrated by the use of numerical bifurcation analysis, sensitivity analysis and numerical simulations. Indeed, bifurcation and numerical analysis of the model predicted a transition between bistable and stable states, which are dependent on the growth factor concentration parameter (GF). The derived predictions confirm experimental observations.

The overview of Mitogen-activated extracellular signal-regulated kinase (MEK)-based dual inhibitor in the treatment of cancers

Mitogen-activated extracellular signal-regulated kinase 1 and 2 (MEK1/2) are the critical components of the mitogen-activated protein kinase/extracellular signal-regulated kinase 1 and 2 (MAPK/ERK1/2) signaling pathway which is one of the well-characterized kinase cascades regulating cell proliferation, differentiation, growth, metabolism, survival and mobility both in normal and cancer cells. The aberrant activation of MAPK/ERK1/2 pathway is a hallmark of numerous human cancers, therefore targeting the components of this pathway to inhibit its dysregulation is a promising strategy for cancer treatment. Enormous efforts have been done in the development of MEK1/2 inhibitors and encouraging advancements have been made, including four inhibitors approved for clinical use. However, due to the multifactorial property of cancer and rapidly arising drug resistance, the clinical efficacy of these MEK1/2 inhibitors as monotherapy are far from ideal. Several alternative strategies have been developed to improve the limited clinical efficacy, including the dual inhibitor which is a single drug molecule able to simultaneously inhibit two targets. In this review, we first introduced the activation and function of the MAPK/ERK1/2 components and discussed the advantages of MEK1/2-based dual inhibitors compared with the single inhibitors and combination therapy in the treatment of cancers. Then, we overviewed the MEK1/2-based dual inhibitors for the treatment of cancers and highlighted the theoretical basis of concurrent inhibition of MEK1/2 and other targets for development of these dual inhibitors. Besides, the status and results of these dual inhibitors in both preclinical and clinical studies were also the focus of this review.

Hepatocellular Carcinoma in Chronic Viral Hepatitis: Where Do We Stand?

Hepatocellular carcinoma (HCC) is one of the major causes of cancer-related death. Although the burden of alcohol- and NASH-related HCC is growing, chronic viral hepatitis (HBV and HCV) remains a major cause of HCC development worldwide. The pathophysiology of viral-related HCC includes liver inflammation, oxidative stress, and deregulation of cell signaling pathways. HBV is particularly oncogenic because, contrary to HCV, integrates in the cell DNA and persists despite virological suppression by nucleotide analogues. Surveillance by six-month ultrasound is recommended in patients with cirrhosis and in "high-risk" patients with chronic HBV infection. Antiviral therapy reduces the risks of development and recurrence of HCC; however, patients with advanced chronic liver disease remain at risk of HCC despite virological suppression/cure and should therefore continue surveillance. Multiple scores have been developed in patients with chronic hepatitis B to predict the risk of HCC development and may be used to stratify individual patient's risk. In patients with HCV-related liver disease who achieve sustained virological response by direct acting antivirals, there is a strong need for markers/scores to predict long-term risk of HCC. In this review, we discuss the most recent advances regarding viral-related HCC.

The Therapeutic Potential of MAPK/ERK Inhibitors in the Treatment of Colorectal Cancer

The MAPK/ERK signaling pathway regulates cancer cell proliferation, apoptosis, inflammation, angiogenesis, metastasis and drug resistance. Mutations and up-regulation of components of the MAPK/ERK signaling pathway, as well as over-activation of this critical signaling pathway, are frequently observed in colorectal carcinomas. Targeting the MAPK/ERK signaling pathway, using specific pharmacological inhibitors, elicits potent anti-tumor effects, supporting the therapeutic potential of these inhibitors in the treatment of CRC. Several drugs have recently been developed for the inhibition of the MEK/ERK pathway in preclinical and clinical settings, such as MEK162 and MK-2206. MEK1/2 inhibitors demonstrate promising efficacy and anticancer activity for the treatment of this malignancy. This review summarizes the current knowledge on the role of the MAPK/ERK signaling pathway in the pathogenesis of CRC and the potential clinical value of synthetic inhibitors of this pathway in preventing CRC progression for a better understanding, and hence, better management of colorectal cancer.

The miR-378c-Samd1 circuit promotes phenotypic modulation of vascular smooth muscle cells and foam cells formation in atherosclerosis lesions

MicroRNAs have emerged as key regulators in vascular diseases and are involved in the formation of atherosclerotic lesions. However, the atherosclerotic-specific MicroRNAs and their functional roles in atherosclerosis are unclear. Here, we report that miR-378c protects against atherosclerosis by directly targeting Sterile Alpha Motif Domain Containing 1 (Samd1), a predicted transcriptional repressor. miR-378c was strikingly reduced in atherosclerotic plaques and blood of acute coronary syndrome (ACS) patients relative to healthy controls. Suppression of miR-378c promoted vascular smooth muscle cells (VSMCs) phenotypic transition during atherosclerosis. We also reported for the first time that Samd1 prolonged immobilization of LDL on the VSMCs, thus facilitated LDL oxidation and subsequently foam cell formation. Further, we found that Samd1 contains predicted DNA binding domain and directly binds to DNA regions as a transcriptional repressor. Together, we uncovered a novel mechanism whereby miR-378c-Samd1 circuit participates in two key elements of atherosclerosis, VSMCs phenotypic transition and LDL oxidation. Our results provided a better understanding of atherosclerosis pathophysiology and potential therapeutic management by targeting miR-378c-Samd1 circuit.

Transcription Landscape of the Early Developmental Biology in Pigs

Since pre- and postnatal development are programmed during early prenatal life, studies addressing the complete transcriptional landscape during organogenesis are needed. Therefore, we aimed to disentangle differentially expressed (DE) genes between fetuses (at 35 days old) and embryos (at 25 days old) through RNA-sequencing analysis using the pig as model. In total, 1705 genes were DE, including the top DE IBSP, COL6A6, HBE1, HBZ, HBB, and NEUROD6 genes, which are associated with developmental transition from embryos to fetuses, such as ossification, skeletal muscle development, extracellular matrix organization, cardiovascular system, erythrocyte differentiation, and neuronal system. In pathway analysis, embryonic development highlighted those mainly related to morphogenic signaling and cell interactions, which are crucial for transcriptional control during the establishment of the main organs in early prenatal development, while pathways related to myogenesis, neuronal development, and cardiac and striated muscle contraction were enriched for fetal development, according to the greater complexity of organs and body structures at this developmental stage. Our findings provide an exploratory and informative transcriptional landscape of pig organogenesis, which might contribute to further studies addressing specific developmental events in pigs and in other mammals.

E2F1 Induces KIF26A Transcription and Promotes Cell Cycle Progression via CDK-RB-E2Fs Feedback Loop in Breast Cancer

Objective

The aim of this study was to investigate the role of KIF26A in breast cancer.

Method

qRT-PCR and immunohistochemistry were conducted to explore KIF26A expression and functional contribution to breast cancer development. MTS, EDU, colony formation assays, and flow cytometry analysis were conducted to assess cell proliferation characteristics and cell cycle progression. A series of 5′-flanking region deletion plasmids and mutating the binding site, with the luciferase reporter assay, were used to identify the core promotor region of KIF26A. The prediction by software and construction of the transcriptional factor plasmids were used to identify the transcriptional factor. Chromatin immunoprecipitation assay could demonstrate transcriptional factor directly binding to the KIF26A promoter. Human Genome Oligo Microarray Assay and gene ontology (GO) and pathway analyses were used to predict the downstream pathway.

Results

Our results showed that in breast cancer tissues, elevated KIF26A expression was significantly correlated with lymph node metastasis. KIF26A could promote proliferation and G0/G1 phase cell cycle progression in breast cancer cells. The core promoter region of the human KIF26A gene was located upstream of the transcription start site at position −395 to −385. The transcriptional factor E2F1 was shown to activate KIF26A expression. Furthermore, KIF26A was shown to inhibit the expression of p21, then activate CDK–RB–E2Fs pathway. The elevated E2F1 can activate the cell cycle progression and the KIF26A expression, forming feedback loop.

Conclusions

The present study demonstrated that KIF26A, directly upregulated by E2F1, promoted cell proliferation and cell cycle progression via CDK–RB–E2Fs feedback loop in breast cancer.

Low E2F2 activity is associated with high genomic instability and PARPi resistance

The E2F family, classically known for a central role in cell cycle, has a number of emerging roles in cancer including angiogenesis, metabolic reprogramming, metastasis and DNA repair. E2F1 specifically has been shown to be a critical mediator of DNA repair; however, little is known about DNA repair and other E2F family members. Here we present an integrative bioinformatic and high throughput drug screening study to define the role of E2F2 in maintaining genomic integrity in breast cancer. We utilized in vitro E2F2 ChIP-chip and over expression data to identify transcriptional targets of E2F2. This data was integrated with gene expression from E2F2 knockout tumors in an MMTV-Neu background. Finally, this data was compared to human datasets to identify conserved roles of E2F2 in human breast cancer through the TCGA breast cancer, Cancer Cell Line Encyclopedia, and CancerRx datasets. Through these methods we predict that E2F2 transcriptionally regulates mediators of DNA repair. Our gene expression data supports this hypothesis and low E2F2 activity is associated with a highly unstable tumor. In human breast cancer E2F2, status was also correlated with a patient's response to PARP inhibition therapy. Taken together this manuscript defines a novel role of E2F2 in cancer progression beyond cell cycle and could impact patient treatment.

Cell dormancy plasticity: quiescence deepens into senescence through a dimmer switch

Both being dormant cellular states, quiescence and senescence are traditionally considered distinct. Quiescence is reversible to proliferation upon growth signals, whereas senescence is irreversible in physiological conditions. Recent findings, however, suggest that quiescence deepening with a decreased proliferative tendency, but not capability, is a common transition path toward senescence in many cell and tissue types. This transition is associated with the continuously increased activation threshold of an RB-E2F-CDK gene network switch.

CCNE1 Amplification as a Predictive Biomarker of Chemotherapy Resistance in Epithelial Ovarian Cancer

Ovarian cancer is the most-deadly gynecologic malignancy, with greater than 14,000 women expected to succumb to the disease this year in the United States alone. In the front-line setting, patients are treated with a platinum and taxane doublet. Although 40–60% of patients achieve complete clinical response to first-line chemotherapy, 25% are inherently platinum-resistant or refractory with a median overall survival of about one year. More than 80% of women afflicted with ovarian cancer will recur. Many attempts have been made to understand the mechanism of platinum and taxane based chemotherapy resistance. However, despite decades of research, few predictive markers of chemotherapy resistance have been identified. Here, we review the current understanding of one of the most common genetic alterations in epithelial ovarian cancer, CCNE1 (cyclin E1) amplification, and its role as a potential predictive marker of cytotoxic chemotherapy resistance. CCNE1 amplification has been identified as a primary oncogenic driver in a subset of high grade serous ovarian cancer that have an unmet clinical need. Understanding the interplay between cyclin E1 amplification and other common ovarian cancer genetic alterations provides the basis for chemotherapeutic resistance in CCNE1 amplified disease. Exploration of the effect of cyclin E1 amplification on the cellular machinery that causes dysregulated proliferation in cancer cells has allowed investigators to explore promising targeted therapies that provide the basis for emerging clinical trials.

Multi-parameter exploration of dynamics of regulatory networks

Over the last twenty years advances in systems biology have changed our views on microbial communities and promise to revolutionize treatment of human diseases. In almost all scientific breakthroughs since time of Newton, mathematical modeling has played a prominent role. Regulatory networks emerged as preferred descriptors of how abundances of molecular species depend on each other. However, the central question on how cellular phenotypes emerge from dynamics of these network remains elusive. The principal reason is that differential equation models in the field of biology (while so successful in areas of physics and physical chemistry), do not arise from first principles, and these models suffer from lack of proper parameterization. In response to these challenges, discrete time models based on Boolean networks have been developed. In this review, we discuss an emerging modeling paradigm that combines ideas from differential equations and Boolean models, and has been developed independently within dynamical systems and computer science communities. The result is an approach that can associate a range of potential dynamical behaviors to a network, arrange the descriptors of the dynamics in a searchable database, and allows for multi-parameter exploration of the dynamics akin to bifurcation theory. Since this approach is computationally accessible for moderately sized networks, it allows, perhaps for the first time, to rationally compare different network topologies based on their dynamics.

Synthesis and biological evaluation of small molecule modulators of CDK8/Cyclin C complex with phenylaminoquinoline scaffold

Background

CDK8/CycC complex has kinase activity towards the carboxyterminal domain of RNA polymerase II, and contributes to the regulation of transcription via association with the mediator complex. Different human malignancies, mainly colorectal and gastric cancers, were produced as a result of overexpression of CDK8/CycC in the mediator complex. Therefore, CDK8/CycC complex represents as a cancer oncogene and it has become a potential target for developing CDK8/CycC modulators.

Methods

A series of nine 4-phenylaminoquinoline scaffold-based compounds 5a-i was synthesized, and biologically evaluated as potential CDK8/CycC complex inhibitors.

Results

The scaffold substituent effects on the intrinsic inhibitory activity toward CDK8/CycC complex are addressed trying to present a novel outlook of CDK8/CycC Complex inhibitors with 4-phenylaminoquinoline scaffold in cancer therapy. The secondary benzenesulfonamide analogues proved to be the most potent compounds in suppressing CDK8/CycC enzyme, whereas, their primary benzenesulfonamide analogues showed inferior activity. Moreover, the benzene reversed sulfonamide analogues were totally inactive.

Discussion

The titled scaffold showed promising inhibitory activity data and there is a crucial role of un/substituted sulfonamido group for CDK8/CycC complex inhibitory activity. Compound 5d showed submicromolar potency against CDK8/CycC (IC₅₀ = 0.639 µM) and it can be used for further investigations and to design another larger library of phenylaminoquinoline scaffold-based analogues in order to establish detailed SARs.

Regulation of Cell Cycle Entry and Exit: A Single Cell Perspective

The transition between proliferating and quiescent states must be carefully regulated to ensure that cells divide to create the cells an organism needs only at the appropriate time and place. Cyclin-dependent kinases (CDKs) are critical for both transitioning cells from one cell cycle state to the next, and for regulating whether cells are proliferating or quiescent. CDKs are regulated by association with cognate cyclins, activating and inhibitory phosphorylation events, and proteins that bind to them and inhibit their activity. The substrates of these kinases, including the retinoblastoma protein, enforce the changes in cell cycle status. Single cell analysis has clarified that competition among factors that activate and inhibit CDK activity leads to the cell's decision to enter the cell cycle, a decision the cell makes before S phase. Signaling pathways that control the activity of CDKs regulate the transition between quiescence and proliferation in stem cells, including stem cells that generate muscle and neurons. © 2020 American Physiological Society. Compr Physiol 10:317-344, 2020.

EXOSC5 as a Novel Prognostic Marker Promotes Proliferation of Colorectal Cancer via Activating the ERK and AKT Pathways

Background and Objective: Exosome component 5 (EXOSC5) is a novel cancer-related gene that is aberrantly expressed in various malignances. However, the molecular mechanism and biological role of EXOSC5 have not been explored in colorectal cancer (CRC). In this study, we investigated the functions and mechanisms by which EXOSC5 promotes the progression of CRC.

Methods: EXOSC5 expressions in CRC cell lines and paired CRC and adjacent normal tissues were measured via quantitative real-time PCR (qRT-PCR), Western blot and immunohistochemistry (IHC). In vitro experiments including colony formation, Cell Counting Kit-8 (CCK-8), and flow cytometry and in vivo tumorigenesis assay were performed to explore the effects of EXOSC5 on growth of CRC. The impacts of EXOSC5 on ERK and Akt signaling pathways were measured by Western blot.

Results: The mRNA and protein expression levels of EXOSC5 were up-regulated in CRC as compared to adjacent normal tissues. IHC analysis indicated that high EXOSC5 level was positively associated with poor prognosis. EXOSC5 overexpression facilitated the growth of CRC cells, while EXOSC5 knockdown led to decreased proliferation, G1/S phase transition arrest. The oncogenic functions of EXOSC5 were associated with activation of the ERK and Akt pathways in CRC.

Conclusion: EXOSC5 is overexpressed in CRC and promotes CRC growth partly through activation of ERK and Akt signaling pathways. Accordingly, EXOSC5 may be a novel oncogene, and acts as a therapeutic target, or prognostic factor for CRC.

HBV-related hepatocarcinogenesis: the role of signalling pathways and innovative ex vivo research models

BACKGROUND

Hepatitis B virus (HBV) is the leading cause of liver cancer, but the mechanisms by which HBV causes liver cancer are poorly understood and chemotherapeutic strategies to cure liver cancer are not available. A better understanding of how HBV requisitions cellular components in the liver will identify novel therapeutic targets for HBV associated hepatocellular carcinoma (HCC).

MAIN BODY

The development of HCC involves deregulation in several cellular signalling pathways including Wnt/FZD/β-catenin, PI3K/Akt/mTOR, IRS1/IGF, and Ras/Raf/MAPK. HBV is known to dysregulate several hepatocyte pathways and cell cycle regulation resulting in HCC development. A number of these HBV induced changes are also mediated through the Wnt/FZD/β-catenin pathway. The lack of a suitable human liver model for the study of HBV has hampered research into understanding pathogenesis of HBV. Primary human hepatocytes provide one option; however, these cells are prone to losing their hepatic functionality and their ability to support HBV replication. Another approach involves induced-pluripotent stem (iPS) cell-derived hepatocytes. However, iPS technology relies on retroviruses or lentiviruses for effective gene delivery and pose the risk of activating a range of oncogenes. Liver organoids developed from patient-derived liver tissues provide a significant advance in HCC research. Liver organoids retain the characteristics of their original tissue, undergo unlimited expansion, can be differentiated into mature hepatocytes and are susceptible to natural infection with HBV.

CONCLUSION

By utilizing new ex vivo techniques like liver organoids it will become possible to develop improved and personalized therapeutic approaches that will improve HCC outcomes and potentially lead to a cure for HBV.

Raddeanin A promotes apoptosis and ameliorates 5-fluorouracil resistance in cholangiocarcinoma cells

BACKGROUND

Bile duct cancer is characterized by fast metastasis and invasion and has been regarded as one of the most aggressive tumors due to the absence of effective diagnosis at an early stage. Therefore, it is in the urgent demand to explore novel diagnostic approaches and therapeutic strategies for bile duct cancer to improve patient survival. Raddeanin A (RA) is extracted from the anemone raddeana regel and has been demonstrated to play antitumor roles in various cancers.

AIM

To investigate the effects of RA treatment on bile duct cancer cells.

METHODS

In this study, four cholangiocarcinoma cell lines (RBE, LIPF155C, LIPF178C, and LICCF) treated with RA were used to test the cell viability. The RA-associated cell functional analysis, 5-fluorouracil (5-Fu) effectiveness as well as cell cycle- and apoptosis-related protein expression were investigated.

RESULTS

RA reduced cell viability in a dose-dependent pattern in four cell lines, and the migration and colony formation abilities were also impaired by RA in RBE and LIPF155C cell lines. RA sensitized cell lines to 5-Fu treatment and enhanced the effects of 5-Fu in cholangiocarcinoma. Also, RA decreased protein expression of Wee1, while the combinational effect of RA and 5-Fu decreased protein expressions of cyclooxygenase-2, B cell lymphoma 2, and Wee1 but increased protein levels of Bax, cyclin D1, and cyclin E.

CONCLUSION

Taken together, the results suggest that RA acts as an anti-cancer agent and enhancer of 5-Fu in bile duct cancer cells via regulating multiple cell cycle and apoptosis-related proteins. This finding provides novel clues to exploring a novel antitumor drug for bile duct cancer.

The novel non-immunological role and underlying mechanisms of B7-H3 in tumorigenesis

B7 homolog 3 (B7-H3) has been proven to be involved in tumorigenesis. An elucidation of its role and underlying mechanisms is essential to an understanding of tumorigenesis and the development of effective clinical applications. B7-H3 is abnormally overexpressed in many types of cancer and is generally associated with a poor clinical prognosis. B7-H3 inhibits the initiation of the "caspase cascade" by the Janus kinase/signal transducers and activators of transcription pathway to resist tumor cell apoptosis. B7-H3 accelerates malignant proliferation by attacking the checkpoint mechanism of the tumor cell cycle through the phosphatidylinositol 3-kinase and protein kinase B pathway. B7-H3 reprograms the metabolism of glucose and lipids and transforms the metabolic flux of tumor cells to promote tumorigenesis. B7-H3 induces abnormal angiogenesis by recruiting vascular endothelial growth factor and matrix metalloproteinase to tumor lesions. B7-H3 strongly promotes tumorigenesis through antiapoptotic, pro-proliferation, metabolism reprogramming, and pro-angiogenesis.

Effect of endocannabinoid signalling on cell fate: life, death, differentiation and proliferation of brain cells

Cell fate events are regulated by different endogenous developmental factors such as the cell micro-environment, external or remote signals and epigenetic factors. Among the many regulatory factors, endocannabinoid-associated signalling pathways are known to conduct several of these events in the developing nervous system and in the adult brain. Interestingly, endocannabinoids exert modulatory actions in both physiological and pathological conditions. Endocannabinoid signalling can promote cell survival by acting on non-transformed brain cells (neurons, astrocytes or oligodendrocytes) and can have either a protumoural or antitumoural effect on transformed cells. Moreover, endocannabinoids are able to attenuate the detrimental effects on neurogenesis and neuroinflammation associated with ageing. Thus, the endocannabinoid system emerges as an important regulator of cell fate, controlling cell survival/cell death decisions depending on the cell type and its environment. LINKED ARTICLES: This article is part of a themed section on 8th European Workshop on Cannabinoid Research. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.10/issuetoc.

PI3k and Stat3: Oncogenes that are Required for Gap Junctional, Intercellular Communication

Gap junctional, intercellular communication (GJIC) is interrupted in cells transformed by oncogenes such as activated Src. The Src effector, Ras, is required for this effect, so that Ras inhibition restores GJIC in Src-transformed cells. Interestingly, the inhibition of the Src effector phosphatidyl-inositol-3 kinase (PI3k) or Signal Transducer and Activator of Transcription-3 (Stat3) pathways does not restore GJIC. In the contrary, inhibition of PI3k or Stat3 in non-transformed rodent fibroblasts or epithelial cells or certain human lung carcinoma lines with extensive GJIC inhibits communication, while mutational activation of PI3k or Stat3 increases GJIC. Therefore, it appears that oncogenes such as activated Src have a dual role upon GJIC; acting as inhibitors of communication through the Ras pathway, and as activators through activation of PI3k or Stat3. In the presence of high Src activity the inhibitory functions prevail so that the net effect is gap junction closure. PI3k and Stat3 constitute potent survival signals, so that their inhibition in non-transformed cells triggers apoptosis which, in turn, has been independently demonstrated to suppress GJIC. The interruption of gap junctional communication would confine the apoptotic event to single cells and this might be essential for the maintenance of tissue integrity. We hypothesize that the GJIC activation by PI3k or Stat3 may be linked to their survival function.

Hypoxia-mediated miR-212-3p downregulation enhances progression of intrahepatic cholangiocarcinoma through upregulation of Rab1a

Rab1a, a member RAS oncogene family, has been reported playing important role in tumor proliferation and migration. However, the role of Rab1a in intrahepatic cholangiocarcinoma (ICC) is not clear. In this study, we found Rab1a was overexpressed in ICC tissues both in mRNA and protein level. Kaplan-meier analysis showed that high expression of Rab1a was associated with poor prognosis of ICC patients. Suppression of Rab1a led to lower proliferation rate and migration ability both in vitro and in vivo by inhibiting process of cell cycle and Epithelial-Mesenchymal Transition (EMT). Further study showed that Rab1a was targeting regulated by miR-212-3p.In addition, expression of Rab1a was increased while miR-212-3p was decreased under hypoxia condition. In conclusion, these findings extend our understanding of Rab1a in progression of ICC, and we found hypoxia/miR-212-3p/Rab1a pathway played important role for progression of ICC. This newly identified pathway should promote the development of novel therapeutic biomarker for ICC.

Identifying robust hysteresis in networks

We present a new modeling and computational tool that computes rigorous summaries of network dynamics over large sets of parameter values. These summaries, organized in a database, can be searched for observed dynamics, e.g., bistability and hysteresis, to discover parameter regimes over which they are supported. We illustrate our approach on several networks underlying the restriction point of the cell cycle in humans and yeast. We rank networks by how robustly they support hysteresis, which is the observed phenotype. We find that the best 6-node human network and the yeast network share similar topology and robustness of hysteresis, in spite of having no homology between the corresponding nodes of the network. Our approach provides a new tool linking network structure and dynamics.

To summarize our understanding of how genes, their products and other cellular actors interact with each other, we often employ networks to describe their interactions. However, networks do not fully specify how the underlying biological system behaves in different conditions, nor how such response evolves in time. We present a new modeling and computational approach that allows us to compute and collect summaries of network dynamics for large sets of parameter values. We can then search these summaries for all observed behavior. We illustrate our approach on networks that govern entry to the cell cycle in humans and yeast. We rank networks based on how robustly they exhibit the experimentally observed behavior of hysteresis. We find similarities in network structure of the best ranked networks in yeast and humans, which are not explained by a common ancestry. Our approach provides a tool linking network structure and the behavior of the underlying system.

Bach2 Promotes B Cell Receptor-Induced Proliferation of B Lymphocytes and Represses Cyclin-Dependent Kinase Inhibitors

BTB and CNC homology 2 (Bach2) is a transcriptional repressor that is required for the formation of the germinal center (GC) and reactions, including class switch recombination and somatic hypermutation of Ig genes in B cells, within the GC. Although BCR-induced proliferation is essential for GC reactions, the function of Bach2 in regulating B cell proliferation has not been elucidated. In this study, we demonstrate that Bach2 is required to sustain high levels of B cell proliferation in response to BCR signaling. Following BCR engagement in vitro, B cells from Bach2-deficient (Bach2-/-) mice showed lower incorporation of BrdU and reduced cell cycle progression compared with wild-type cells. Bach2-/- B cells also underwent increased apoptosis, as evidenced by an elevated frequency of sub-G1 cells and early apoptotic cells. Transcriptome analysis of BCR-engaged B cells from Bach2-/- mice revealed reduced expression of the antiapoptotic gene Bcl2l1 encoding Bcl-xL and elevated expression of cyclin-dependent kinase inhibitor (CKI) family genes, including Cdkn1a, Cdkn2a, and Cdkn2b Reconstitution of Bcl-xL expression partially rescued the proliferation defect of Bach2-/- B cells. Chromatin immunoprecipitation experiments showed that Bach2 bound to the CKI family genes, indicating that these genes are direct repression targets of Bach2. These findings identify Bach2 as a requisite factor for sustaining high levels of BCR-induced proliferation, survival, and cell cycle progression, and it promotes expression of Bcl-xL and repression of CKI genes. BCR-induced proliferation defects may contribute to the impaired GC formation observed in Bach2-/- mice.

Loss of microRNA-128 promotes cardiomyocyte proliferation and heart regeneration

The goal of replenishing the cardiomyocyte (CM) population using regenerative therapies following myocardial infarction (MI) is hampered by the limited regeneration capacity of adult CMs, partially due to their withdrawal from the cell cycle. Here, we show that microRNA-128 (miR-128) is upregulated in CMs during the postnatal switch from proliferation to terminal differentiation. In neonatal mice, cardiac-specific overexpression of miR-128 impairs CM proliferation and cardiac function, while miR-128 deletion extends proliferation of postnatal CMs by enhancing expression of the chromatin modifier SUZ12, which suppresses p27 (cyclin-dependent kinase inhibitor) expression and activates the positive cell cycle regulators Cyclin E and CDK2. Furthermore, deletion of miR-128 promotes cell cycle re-entry of adult CMs, thereby reducing the levels of fibrosis, and attenuating cardiac dysfunction in response to MI. These results suggest that miR-128 serves as a critical regulator of endogenous CM proliferation, and might be a novel therapeutic target for heart repair.

NRBP2 Overexpression Inhibits Cell Proliferation and Migration and Increases Cisplatin Sensitivity in Intrahepatic Cholangiocarcinoma

Aims:

Methods:

Results:

Conclusions:

Overexpression of RAB34 correlates with poor prognosis and tumor progression in hepatocellular carcinoma

RAB34, a protein belonging to the RAB family, is involved in protein transport, repositioning of lysosomes and activation of micropinocytosis. However, few studies have reported its function in human epithelial cancers. Immunohistochemistry (IHC) and western blotting were used to detect expression of RAB34 at the tissue and cell levels. Cell Counting Kit-8 (CCK-8), EDU assay and flow cytometry were used for analyzing cell proliferation. Transwell and scratch wound healing assays were used for assessing cell migration ability. Western blotting was used for detecting expression of E-cadherin and N-cadherin. In the present study, we found that both DNA copy and protein level of RAB34 were upregulating in human hepatocellular carcinoma (HCC) tissues when compared with that in adjacent tissues. Analysis of the correlation between RAB34 expression and clinicopathological features showed that patients with overexpression of RAB34 consistently had large tumor size, vessel invasion and poor tumor grade. Furthermore, overall survival analysis showed that patients with upregulated expression of RAB34 were associated with poor prognosis. Moreover, cell function experiments showed that suppression of RAB34 led to a lower proliferation rate and migration ability. In addition, this phenomenon may be attributed to cell cycle phase G1 arrest and mesenchymal-epithelial transition under condition of RAB34 suppression. The present study demonstrated that RAB34 plays an important role in the initiation and progression of HCC. Our results suggest a new therapeutic target for the clinical treatment of HCC.

Regulation of HC11 mouse breast epithelial cell differentiation by the E-cadherin/Rac axis

It was previously demonstrated that differentiation of some established breast epithelial cell lines requires confluence and stimulation with hydrocortisone, insulin and prolactin inducers. We and others previously demonstrated that E-cadherin engagement, which is favored under conditions of confluence, increases the levels and activity of the Rac small GTPase. To investigate the functional relationship between the transforming ability of Rac and its role as an integral component of the differentiative E-cadherin signaling pathway, we introduced a mutationally activated form of Rac, Rac^V12, into the mouse breast epithelium-derived cell line, HC11. Our results demonstrate that the strength of the Rac signal is key for the outcome of the differentiation process; cRac1 is critically required for differentiation, and at low levels, mutationally activated Rac^V12 is able to increase differentiation, presumably reinforcing the E-cadherin/Rac differentiative signal. However, high Rac^V12 expression blocked differentiation concomitant with E-cadherin downregulation, while inducing neoplastic transformation. Therefore, the intensity of the Rac signal is a central determinant in the balance between cell proliferation vs differentiation, two fundamentally opposed processes, a finding which could also have important therapeutic implications.

Rationally designed hecogenin thiosemicarbazone analogs as novel MEK inhibitors for the control of breast malignancies

Natural products have documented oncology success history as valuable scaffolds for selective target modulation. Herein, the sapogenin hecogenin (1) was screened for its anti-breast cancer inhibitory capacity using in vitro assays, including proliferation, cytotoxicity, migration, invasion assays, and Western blotting. The results identified 1 as a propitious hit with modest activities attributed to the concurrent down-regulation of mitogen activated protein kinase kinase/extracellular signal-regulated kinase (MEK) distinctive downstream effectors. Guided by in silico 3D-structural insights of MAPK kinase domain, an extension strategy was adopted at 1's C-3 and C-12 aimed at the design of novel hecogenin-based analogs with improved target binding affinity. Thirty-three analogs were prepared and tested, among which hecogenin 12-(3'-methylphenyl thiosemicarbazone) (30) displayed the most potent selective anticancer effects. Analog 30 demonstrated antiproliferative, antimigratory and anti-invasive activities at low μM level, compared to the negligible effect on the non-tumorigenic MCF-10A mammary epithelial cells. Durable regression of breast tumor xenografts in athymic nude mice was observed after treatments with 30, compared to its parent hecogenin at the same dose regimen, confirmed the hit-to-lead promotion of this analog. Hecogenin-12-thiosemicarbazones, represented by 30, is a novel MEK inhibitory lead class to control breast neoplasms.

Aspirin therapy reduces the ability of platelets to promote colon and pancreatic cancer cell proliferation: Implications for the oncoprotein c-MYC

Aspirin, an anti-inflammatory and antithrombotic drug, has become the focus of intense research as a potential anticancer agent owing to its ability to reduce tumor proliferation in vitro and to prevent tumorigenesis in patients. Studies have found an anticancer effect of aspirin when used in low, antiplatelet doses. However, the mechanisms through which low-dose aspirin works are poorly understood. In this study, we aimed to determine the effect of aspirin on the cross talk between platelets and cancer cells. For our study, we used two colon cancer cell lines isolated from the same donor but characterized by different metastatic potential, SW480 (nonmetastatic) and SW620 (metastatic) cancer cells, and a pancreatic cancer cell line, PANC-1 (nonmetastatic). We found that SW480 and PANC-1 cancer cell proliferation was potentiated by human platelets in a manner dependent on the upregulation and activation of the oncoprotein c-MYC. The ability of platelets to upregulate c-MYC and cancer cell proliferation was reversed by an antiplatelet concentration of aspirin. In conclusion, we show for the first time that inhibition of platelets by aspirin can affect their ability to induce cancer cell proliferation through the modulation of the c-MYC oncoprotein.

TLE3 represses colorectal cancer proliferation by inhibiting MAPK and AKT signaling pathways

Background

Transducin-like enhancer of Split3 (TLE3) serves as a transcriptional corepressor during cell differentiation and shows multiple roles in different kinds of cancers. Recently, TLE3 together with many other genes involved in Wnt/β-catenin pathway were detected hyper-methylated in colorectal cancer (CRC). However, the potential role and the underlying mechanism of TLE3 in CRC progression remain scarce.

Methods

Gene expression profiles were analyzed in The Cancer Genome Atlas (TCGA) microarray dataset of 41 normal colorectal intestine tissues and 465 CRC tissues. Western blot and Real-time Quantitative PCR (RT-qPCR) were respectively performed to detect protein and mRNA expression in 8 pairs of CRC tissue and matched adjacent normal mucosa. Immunohistochemistry (IHC) was conducted to evaluate TLE3 protein expression in 105 paraffin-embedded, archived human CRC tissues from patients, whose survival data were analyzed with Kaplan-Meier method. In vitro experiments including MTT assay, colony formation assay, and soft agar formation assay were used to investigate the effects of TLE3 on CRC cell growth and proliferation. Additionally, subcutaneous tumorigenesis assay was performed in nude mice to confirm the effects of TLE3 in vivo. Furthermore, gene set enrichment analysis (GSEA) was run to explore potential mechanism of TLE3 in CRC, and then we measured the distribution of CRC cell cycle phases and apoptosis by flow cytometry, as well as the impacts of TLE3 on MAPK and AKT signaling pathways by Western blot and RT-qPCR.

Results

TLE3 was significantly down-regulated in 465 CRC tissues compared with 41 normal tissues. Both protein and mRNA expressions of TLE3 were down-regulated in CRC compared with matched adjacent normal mucosa. Lower expression of TLE3 was significantly associated with poorer survival of patients with CRC. Besides, knock down of TLE3 promoted CRC cell growth and proliferation, while overexpression of TLE3 showed suppressive effects. Furthermore, overexpression of TLE3 caused G1-S phase transition arrest, inhibition of MAPK and AKT pathways, and up-regulation of p21Cip1/WAF1 and p27Kip1.

Conclusion

This study indicated that TLE3 repressed CRC proliferation partly through inhibition of MAPK and AKT signaling pathways, suggesting the possibility of TLE3 as a biomarker for CRC prognosis.

Electronic supplementary material

The online version of this article (doi:10.1186/s13046-016-0426-8) contains supplementary material, which is available to authorized users.

Relationship between cancer mutations and parameter sensitivity in Rb pathway

It has long been known that formation of all sorts of tumors is largely owing to the genomic variations. Oncogenic mutations are often found focused on one or more important pathways which indicate that it is meaningful to investigate oncogenic mutations and oncogenic mechanisms from the point of view of biological network. Recently, we found that in apoptosis pathway of mammalian cell, mutations that cause large variations on the bifurcation point are more probably oncogenic mutations. Here, we used the Rb-E2F pathway in mammalian cell in response to growth factor as another example to verify this correlation. To conduct this study, nonlinear dynamics equations that describe the behavior of the Rb-E2F pathway was first constructed. Then we identified sensitive parameters which have a great influence on the system's bifurcation point. And we found that the sensitive parameters are highly related to high-frequency oncogenic mutations after comparing the results of parameter sensitivity analysis with profile of known cancer mutations. Moreover, the position of bifurcation point rather than concentration of a certain protein is a better measurement to determine biological network's function. Our results further confirm that nonlinear dynamics analysis of biological networks is an important way to understand oncogenesis. And the analysis method can become a powerful tool to understand and analyze the function of biological network.

Increased metastasis with loss of E2F2 in Myc-driven tumors

In human breast cancer, mortality is associated with metastasis to distant sites. Therefore, it is critical to elucidate the biological mechanisms that underlie tumor progression and metastasis. Using signaling pathway signatures we previously predicted a role for E2F transcription factors in Myc induced tumors. To test this role we interbred MMTV-Myc transgenic mice with E2F knockouts. Surprisingly, we observed that the loss of E2F2 sharply increased the percentage of lung metastasis in MMTV-Myc transgenic mice. Examining the gene expression profile from these tumors, we identified genetic components that were potentially involved in mediating metastasis. These genes were filtered to uncover the genes involved in metastasis that also impacted distant metastasis free survival in human breast cancer. In order to elucidate the mechanism by which E2F2 loss enhanced metastasis we generated knockdowns of E2F2 in MDA-MB-231 cells and observed increased migration in vitro and increased lung colonization in vivo. We then examined genes that were differentially regulated between tumors from MMTV-Myc, MMTV-Myc E2F2^−/−, and lung metastases samples and identified PTPRD. To test the role of PTPRD in E2F2-mediated breast cancer metastasis, we generated a knockdown of PTPRD in MDA-MB-231 cells. We noted that decreased levels of PTPRD resulted in decreased migration in vitro and decreased lung colonization in vivo. Taken together, these data indicate that E2F2 loss results in increased metastasis in breast cancer, potentially functioning through a PTPRD dependent mechanism.

Crosstalk between E2f1 and c-Myc mediates hepato-protective effect of royal jelly on taxol-induced damages

Previous histopathological studies have shown the hepatotoxicity of paclitaxel (TXL). However, there is little known about the molecular pathway(s) of TXL-induced hepatotoxicity. Therefore, this study aimed to uncover the role of two transcription factors in the TXL-induced hepatotoxicity. Moreover, the hepato-protective effect of royal jelly (RJ) on TXL-induced toxicity was investigated. Wistar rats were divided into control and test groups. The test groups along with TXL received various doses of RJ (0, 50, 100 and 150 mg/kg, body weight). Biochemical hepatic functional assays, histopathological studies and hepatic superoxide dismutase level were determined. Additionally, the expression of E2f1 and cellular-myelocytomatosis (c-Myc) at messenger RNA (mRNA) level in the liver was evaluated. The hepatic functional biomarkers showed a significant ( p < 0.05) elevation in the TXL-received animals, while RJ administration for 28 days resulted in a remarkable reduction in TXL-elevated alkaline phosphatase, alanine transaminase and lactate dehydrogenase levels. The TXL-treated animals showed a significant ( p < 0.05) up-regulation of E2f1 and down-regulation of c-Myc at mRNA level, respectively. RJ lowered the expression of E2f1 while enhanced the expression of c-Myc in a dose-dependent manner. Our data suggest the hepato-protective effects of RJ on TXL-induced toxicity, which may attribute to a clear crosstalk between E2f1 and c-Myc as two regulators of liver growth.

Derepression of hTERT gene expression promotes escape from oncogene-induced cellular senescence

Oncogene-induced senescence (OIS) is a critical tumor-suppressing mechanism that restrains cancer progression at premalignant stages, in part by causing telomere dysfunction. Currently it is unknown whether this proliferative arrest presents a stable and therefore irreversible barrier to cancer progression. Here we demonstrate that cells frequently escape OIS induced by oncogenic H-Ras and B-Raf, after a prolonged period in the senescence arrested state. Cells that had escaped senescence displayed high oncogene expression levels, retained functional DNA damage responses, and acquired chromatin changes that promoted c-Myc-dependent expression of the human telomerase reverse transcriptase gene (hTERT). Telomerase was able to resolve existing telomeric DNA damage response foci and suppressed formation of new ones that were generated as a consequence of DNA replication stress and oncogenic signals. Inhibition of MAP kinase signaling, suppressing c-Myc expression, or inhibiting telomerase activity, caused telomere dysfunction and proliferative defects in cells that had escaped senescence, whereas ectopic expression of hTERT facilitated OIS escape. In human early neoplastic skin and breast tissue, hTERT expression was detected in cells that displayed features of senescence, suggesting that reactivation of telomerase expression in senescent cells is an early event during cancer progression in humans. Together, our data demonstrate that cells arrested in OIS retain the potential to escape senescence by mechanisms that involve derepression of hTERT expression.