Cell cycle arrest by transforming growth factor beta1 near G1/S is mediated by acute abrogation of prereplication complex activation involving an Rb-MCM interaction

The functional roles of competitive endogenous RNA (ceRNA) networks in apoptosis in human cancers: The circRNA/miRNA/mRNA regulatory axis and cell signaling pathways

Circular RNAs are noncoding RNAs with circular conformation mainly due to backsplicing event. CircRNAs can potentially impact cell biological processes by interacting with cell signaling pathways. Numerous circRNAs have been found to be aberrantly expressed in a variety of cancers. These RNAs can act as ceRNA (competitive endogenous RNA) by sponging certain miRNAs to form circRNA/miRNA/mRNA networks. Dysregulation of ceRNA networks may lead to dysfunctions in various cell pathways, which modulate apoptosis-associated genes and ultimately result in cancer progression. Since disruption of apoptosis is one of the leading causes of cancer development, one approach for cancer treatment is to drive cells toward apoptosis. In this review, we present a summary of studies on the role of ceRNA networks in cellular signaling pathways that regulate apoptosis; these networks are suggested to be potential biomarkers for cancer treatment.

Identification of ATP-Competitive Human CMG Helicase Inhibitors for Cancer Intervention that Disrupt CMG-Replisome Function

The human CMG helicase (Cdc45-MCM-GINS) is a novel target for anticancer therapy. Tumor-specific weaknesses in the CMG are caused by oncogene-driven changes that adversely affect CMG function, and CMG activity is required for recovery from replicative stresses such as chemotherapy. Herein, we developed an orthogonal biochemical screening approach and identified CMG inhibitors (CMGi) that inhibit ATPase and helicase activities in an ATP-competitive manner at low micromolar concentrations. Structure-activity information, in silico docking, and testing with synthetic chemical compounds indicate that CMGi require specific chemical elements and occupy ATP-binding sites and channels within minichromosome maintenance (MCM) subunits leading to the ATP clefts, which are likely used for ATP/ADP ingress or egress. CMGi are therefore MCM complex inhibitors (MCMi). Biologic testing shows that CMGi/MCMi inhibit cell growth and DNA replication using multiple molecular mechanisms distinct from other chemotherapy agents. CMGi/MCMi block helicase assembly steps that require ATP binding/hydrolysis by the MCM complex, specifically MCM ring assembly on DNA and GINS recruitment to DNA-loaded MCM hexamers. During the S-phase, inhibition of MCM ATP binding/hydrolysis by CMGi/MCMi causes a "reverse allosteric" dissociation of Cdc45/GINS from the CMG that destabilizes replisome components Ctf4, Mcm10, and DNA polymerase-α, -δ, and -ε, resulting in DNA damage. CMGi/MCMi display selective toxicity toward multiple solid tumor cell types with K-Ras mutations, targeting the CMG and inducing DNA damage, Parp cleavage, and loss of viability. This new class of CMGi/MCMi provides a basis for small chemical development of CMG helicase-targeted anticancer compounds with distinct mechanisms of action.

Deciphering CD59: Unveiling Its Role in Immune Microenvironment and Prognostic Significance

BACKGROUND

CD59, a GPI-anchored membrane protein, protects cancer cells from complement-dependent cytotoxicity (CDC) by inhibiting the formation of the membrane attack complex (MAC). It has been demonstrated to be overexpressed in most solid tumors, where it facilitates tumor cell escape from complement surveillance. The role of CD59 in cancer growth and interactions between CD59 and immune cells that modulate immune evasion has not been well explored.

METHODS

Using cancer patient database from The Cancer Genome Atlas (TCGA) and other public databases, we analyzed CD59 expression, its prognostic significance, and its association with immune cell infiltration in the tumor microenvironment, identifying associated genomic and functional networks and validating findings with invitro cell-line experimental data.

RESULTS

This article describes the abundant expression of CD59 in multiple tumors such as cervical squamous cell carcinoma (CESC), kidney renal cell carcinoma (KIRC), glioblastoma multiforme (GBM), head and neck squamous cell carcinoma (HNSC), and stomach adenocarcinoma (STAD), as well as in pan-cancer, using The Cancer Genome Atlas (TCGA) database and confirmed using multiple cancer cell lines. The expression of CD59 significantly alters the overall survival (OS) of patients with multiple malignancies such as CESC, GBM, HNSC, and STAD. Further, the correlation between CD59 and Treg and/or MDSC in the tumor microenvironment (TME) has shown to be strongly associated with poor outcomes in CESC, GBM, HNSC, and STAD as these tumors express high FOXP3 compared to KIRC. Moreover, unfavorable outcomes were strongly associated with the expression of CD59 and M2 tumor-associated macrophage infiltration in the TME via the IL10/pSTAT3 pathway in CESC and GBM but not in KIRC. In addition, TGFβ1-dominant cancers such as CESC, GBM, and HNSC showed a high correlation between CD59 and TGFβ1, leading to suppression of cytotoxic T cell activity.

CONCLUSION

Overall, the correlation between CD59 and immune cells predicts its prognosis as unfavorable in CESC, GBM, HNSC, and STAD while being favorable in KIRC.

Signaling pathways in colorectal cancer implications for the target therapies

Colorectal carcinoma (CRC) stands as a pressing global health issue, marked by the unbridled proliferation of immature cells influenced by multifaceted internal and external factors. Numerous studies have explored the intricate mechanisms of tumorigenesis in CRC, with a primary emphasis on signaling pathways, particularly those associated with growth factors and chemokines. However, the sheer diversity of molecular targets introduces complexity into the selection of targeted therapies, posing a significant challenge in achieving treatment precision. The quest for an effective CRC treatment is further complicated by the absence of pathological insights into the mutations or alterations occurring in tumor cells. This study reveals the transfer of signaling from the cell membrane to the nucleus, unveiling recent advancements in this crucial cellular process. By shedding light on this novel dimension, the research enhances our understanding of the molecular intricacies underlying CRC, providing a potential avenue for breakthroughs in targeted therapeutic strategies. In addition, the study comprehensively outlines the potential immune responses incited by the aberrant activation of signaling pathways, with a specific focus on immune cells, cytokines, and their collective impact on the dynamic landscape of drug development. This research not only contributes significantly to advancing CRC treatment and molecular medicine but also lays the groundwork for future breakthroughs and clinical trials, fostering optimism for improved outcomes and refined approaches in combating colorectal carcinoma.

Targeting SMAD-Dependent Signaling: Considerations in Epithelial and Mesenchymal Solid Tumors

SMADs are the canonical intracellular effector proteins of the TGF-β (transforming growth factor-β). SMADs translocate from plasma membrane receptors to the nucleus regulated by many SMAD-interacting proteins through phosphorylation and other post-translational modifications that govern their nucleocytoplasmic shuttling and subsequent transcriptional activity. The signaling pathway of TGF-β/SMAD exhibits both tumor-suppressing and tumor-promoting phenotypes in epithelial-derived solid tumors. Collectively, the pleiotropic nature of TGF-β/SMAD signaling presents significant challenges for the development of effective cancer therapies. Here, we review preclinical studies that evaluate the efficacy of inhibitors targeting major SMAD-regulating and/or -interacting proteins, particularly enzymes that may play important roles in epithelial or mesenchymal compartments within solid tumors.

Navigating the Cytokine Seas: Targeting Cytokine Signaling Pathways in Cancer Therapy

Cancer remains one of the leading causes of morbidity and mortality worldwide, necessitating continuous efforts to develop effective therapeutic strategies. Over the years, advancements in our understanding of the complex interplay between the immune system and cancer cells have led to the development of immunotherapies that revolutionize cancer treatment. Cytokines, as key regulators of the immune response, are involved in both the initiation and progression of cancer by affecting inflammation and manipulating multiple intracellular signaling pathways that regulate cell growth, proliferation, and migration. Cytokines, as key regulators of inflammation, have emerged as promising candidates for cancer therapy. This review article aims to provide an overview of the significance of cytokines in cancer development and therapy by highlighting the importance of targeting cytokine signaling pathways as a potential therapeutic approach.

Loss of Function of the Retinoblastoma Gene Affects Gap Junctional Intercellular Communication and Cell Fate in Osteoblasts

Loss of function of the Retinoblastoma gene (RB1) due to mutations is commonly seen in human osteosarcomas. One of the Rb1 gene functions is to facilitate cell fate from mesenchymal stem cells to osteoblasts and prevent adipocyte differentiations. In this study, we demonstrate that a stable reduction of Rb1 expression (RbKD) in murine osteoblasts causes them to express higher levels of PPAR-ɣ and other adipocyte-specific transcription factors while retaining high expression of osteoblast-specific transcription factors, Runx2/Cbfa1 and SP7/Osterix. Inhibition of gap junctional intercellular communication (GJIC) in osteoblasts is another mechanism that causes osteoblasts to transdifferentiate to adipocytes. We found that preosteoblasts exposed to osteoblast differentiating media (DP media) increased GJIC. RbKD cells showed reduced GJIC along with a reduction in expression of Cx43, the protein that mediates GJIC. Other membrane associated adhesion protein Cadherin 11 (Cad11) was also decreased. Since PPAR-ɣ is increased with Rb1 loss, we wondered if the reduction of this transcription factor would reverse the changes observed. Reduction of PPAR-ɣ in control osteoblasts slightly increased bone-specific expression and reduced adipocytic expression as expected along with an increase in Cad11 and Cx43 expression. GJIC remained high and was unaffected by a reduction in PPAR-ɣ in control cells. Knockdown of PPAR-ɣ in RbKD cells reduced adipocyte gene expression, while osteoblast-specific expression showed improvement. Cx43, Cad11 and GJIC remained unaffected by PPAR-ɣ reduction. Our observations suggest that increased PPAR-ɣ that happens with Rb1 loss only affects osteoblast-adipocyte-specific gene expression but does not completely reverse Cx43 gene expression or GJIC. Therefore, these effects may represent independent events triggered by Rb1loss and/or the differentiation process.

Mutual regulation of TGFβ-induced oncogenic EMT, cell cycle progression and the DDR

TGFβ signaling and the DNA damage response (DDR) are two cellular toolboxes with a strong impact on cancer biology. While TGFβ as a pleiotropic cytokine affects essentially all hallmarks of cancer, the multifunctional DDR mostly orchestrates cell cycle progression, DNA repair, chromatin remodeling and cell death. One oncogenic effect of TGFβ is the partial activation of epithelial-to-mesenchymal transition (EMT), conferring invasiveness, cellular plasticity and resistance to various noxae. Several reports show that both individual networks as well as their interface affect chemo-/radiotherapies. However, the underlying mechanisms remain poorly resolved. EMT often correlates with TGFβ-induced slowing of proliferation, yet numerous studies demonstrate that particularly the co-activated EMT transcription factors counteract anti-proliferative signaling in a partially non-redundant manner. Collectively, evidence piled up over decades underscore a multifaceted, reciprocal inter-connection of TGFβ signaling / EMT with the DDR / cell cycle progression, which we will discuss here. Altogether, we conclude that full cell cycle arrest is barely compatible with the propagation of oncogenic EMT traits and further propose that 'EMT-linked DDR plasticity' is a crucial, yet intricate facet of malignancy, decisively affecting metastasis formation and therapy resistance.

Pharmacophore mapping approach to find anti-cancer phytochemicals with metformin-like activities against transforming growth factor (TGF)-beta receptor I kinase: An in silico study

The most frequently prescribed first-line treatment for type II diabetes mellitus is metformin. Recent reports asserted that this diabetes medication can also shield users from cancer. Metformin induces cell cycle arrest in cancer cells. However, the exact mechanism by which this occurs in the cancer system is yet to be elucidated. Here, we investigated the impact of metformin on cell cycle arrest in cancer cells utilizing transforming growth factor (TGF)-beta pathway. TGF-ß pathway has significant effect on cell progression and growth. In order to gain an insight on the underlying molecular mechanism of metformin's effect on TGF beta receptor 1 kinase, molecular docking was performed. Metformin was predicted to interact with transforming growth factor (TGF)-beta receptor I kinase based on molecular docking and molecular dynamics simulations. Furthermore, pharmacophore was generated for metformin-TGF-ßR1 complex to hunt for novel compounds having similar pharmacophore as metformin with enhanced anti-cancer potentials. Virtual screening with 29,000 natural compounds from NPASS database was conducted separately for the generated pharmacophores in Ligandscout® software. Pharmacophore mapping showed 60 lead compounds for metformin-TGF-ßR1 complex. Molecular docking, molecular dynamics simulation for 100 ns and ADMET analysis were performed on these compounds. Compounds with CID 72473, 10316977 and 45140078 showed promising binding affinities and formed stable complexes during dynamics simulation with aforementioned protein and thus have potentiality to be developed into anti-cancer medicaments.

Identification of Selective ATP-Competitive CMG Helicase Inhibitors for Cancer Intervention that Disrupt CMG-Replisome Function

The human CMG helicase (Cdc45-MCM-GINS) is a novel target for anti-cancer therapy due to tumor-specific weaknesses in CMG function induced by oncogenic changes and the need for CMG function during recovery from replicative stresses such as chemotherapy. Here, we developed an orthogonal biochemical screening approach and identified selective CMG inhibitors (CMGi) that inhibit ATPase and helicase activities in an ATP-competitive manner at low micromolar concentrations. Structure-activity information and in silico docking indicate that CMGi occupy ATP binding sites and channels within MCM subunits leading to the ATP clefts, which are likely used for ATP/ADP ingress or egress. CMGi inhibit cell growth and DNA replication using multiple molecular mechanisms. CMGi block helicase assembly steps that require ATP binding/hydrolysis by the MCM complex, specifically MCM ring assembly on DNA and GINS recruitment to DNA-loaded MCM hexamers. During S-phase, inhibition of MCM ATP binding/hydrolysis by CMGi causes a 'reverse allosteric' dissociation of Cdc45/GINS from the CMG that destabilizes the replisome and disrupts interactions with Ctf4, Mcm10, and DNA polymerase-α, -δ, -ε, resulting in DNA damage. These novel CMGi are selectively toxic toward tumor cells and define a new class of CMG helicase-targeted anti-cancer compounds with distinct mechanisms of action.

Investigating the Role of TGF-β Signaling Pathways in Human Corneal Endothelial Cell Primary Culture

Corneal endothelial diseases are the leading cause of corneal transplantation. The global shortage of donor corneas has resulted in the investigation of alternative methods, such as cell therapy and tissue-engineered endothelial keratoplasty (TEEK), using primary cultures of human corneal endothelial cells (hCECs). The main challenge is optimizing the hCEC culture process to increase the endothelial cell density (ECD) and overall yield while preventing endothelial-mesenchymal transition (EndMT). Fetal bovine serum (FBS) is necessary for hCEC expansion but contains TGF-βs, which have been shown to be detrimental to hCECs. Therefore, we investigated various TGF-β signaling pathways using inhibitors to improve hCEC culture. Initially, we confirmed that TGF-β1, 2, and 3 induced EndMT on confluent hCECs without FBS. Using this TGF-β-induced EndMT model, we validated NCAM as a reliable biomarker to assess EndMT. We then demonstrated that, in a culture medium containing 8% FBS for hCEC expansion, TGF-β1 and 3, but not 2, significantly reduced the ECD and caused EndMT. TGF-β receptor inhibition had an anti-EndMT effect. Inhibition of the ROCK pathway, notably that of the P38 MAPK pathway, increased the ECD, while inhibition of the ERK pathway decreased the ECD. In conclusion, the presence of TGF-β1 and 3 in 8% FBS leads to a reduction in ECD and induces EndMT. The use of SB431542 or LY2109761 may prevent EndMT, while Y27632 or Ripasudil, and SB203580 or SB202190, can increase the ECD.

Genes of the Ubiquitin Proteasome System Qualify as Differential Markers in Malignant Glioma of Astrocytic and Oligodendroglial Origin

We have mined public genomic datasets to identify genes coding for components of the ubiquitin proteasome system (UPS) that may qualify as potential diagnostic and therapeutic targets in the three major glioma types, astrocytoma (AS), glioblastoma (GBM), and oligodendroglioma (ODG). In the Sun dataset of glioma (GEO ID: GSE4290), expression of the genes UBE2S and UBE2C, which encode ubiquitin conjugases important for cell-cycle progression, distinguished GBM from AS and ODG. KEGG analysis showed that among the ubiquitin E3 ligase genes differentially expressed, the Notch pathway was significantly over-represented, whereas among the E3 ligase adaptor genes the Hippo pathway was over-represented. We provide evidence that the UPS gene contributions to the Notch and Hippo pathway signatures are related to stem cell pathways and can distinguish GBM from AS and ODG. In the Sun dataset, AURKA and TPX2, two cell-cycle genes coding for E3 ligases, and the cell-cycle gene coding for the E3 adaptor CDC20 were upregulated in GBM. E3 ligase adaptor genes differentially expressed were also over-represented for the Hippo pathway and were able to distinguish classic, mesenchymal, and proneural subtypes of GBM. Also over-expressed in GBM were PSMB8 and PSMB9, genes encoding subunits of the immunoproteasome. Our transcriptome analysis provides a strong rationale for UPS members as attractive therapeutic targets for the development of more effective treatment strategies in malignant glioma. Ubiquitin proteasome system and glioblastoma: E1-ubiquitin-activating enzyme, E2-ubiquitin-conjugating enzyme, E3-ubiquitin ligase. Ubiquitinated substrates of E3 ligases may be degraded by the proteasome. Expression of genes for specific E2 conjugases, E3 ligases, and genes for proteasome subunits may serve as differential markers of subtypes of glioblastoma.

The role of Lamin B2 in human diseases

Lamin B2 (LMNB2), on the inner side of the nuclear envelope, constitutes the nuclear skeleton by connecting with other nuclear proteins. LMNB2 is involved in a wide range of nuclear functions, including DNA replication and stability, regulation of chromatin, and nuclear stiffness. Moreover, LMNB2 regulates several cellular processes, such as tissue development, cell cycle, cellular proliferation and apoptosis, chromatin localization and stability, and DNA methylation. Besides, the influence of abnormal expression and mutations of LMNB2 has been gradually discovered in cancers and laminopathies. Therefore, this review summarizes the recent advances of LMNB2-associated biological roles in physiological or pathological conditions, with a particular emphasis on cancers and laminopathies, as well as the potential mechanism of LMNB2 in related cancers.

The CMG helicase and cancer: a tumor "engine" and weakness with missing mutations

The replicative Cdc45-MCM-GINS (CMG) helicase is a large protein complex that functions in the DNA melting and unwinding steps as a component of replisomes during DNA replication in mammalian cells. Although the CMG performs this important role in cell growth, the CMG is not a simple bystander in cell cycle events. Components of the CMG, specifically the MCM precursors, are also involved in maintaining genomic stability by regulating DNA replication fork speeds, facilitating recovery from replicative stresses, and preventing consequential DNA damage. Given these important functions, MCM/CMG complexes are highly regulated by growth factors such as TGF-ß1 and by signaling factors such as Myc, Cyclin E, and the retinoblastoma protein. Mismanagement of MCM/CMG complexes when these signaling mediators are deregulated, and in the absence of the tumor suppressor protein p53, leads to increased genomic instability and is a contributor to tumorigenic transformation and tumor heterogeneity. The goal of this review is to provide insight into the mechanisms and dynamics by which the CMG is regulated during its assembly and activation in mammalian genomes, and how errors in CMG regulation due to oncogenic changes promote tumorigenesis. Finally, and most importantly, we highlight the emerging understanding of the CMG helicase as an exploitable vulnerability and novel target for therapeutic intervention in cancer.

DNA replication: Mechanisms and therapeutic interventions for diseases

Accurate and integral cellular DNA replication is modulated by multiple replication-associated proteins, which is fundamental to preserve genome stability. Furthermore, replication proteins cooperate with multiple DNA damage factors to deal with replication stress through mechanisms beyond their role in replication. Cancer cells with chronic replication stress exhibit aberrant DNA replication and DNA damage response, providing an exploitable therapeutic target in tumors. Numerous evidence has indicated that posttranslational modifications (PTMs) of replication proteins present distinct functions in DNA replication and respond to replication stress. In addition, abundant replication proteins are involved in tumorigenesis and development, which act as diagnostic and prognostic biomarkers in some tumors, implying these proteins act as therapeutic targets in clinical. Replication-target cancer therapy emerges as the times require. In this context, we outline the current investigation of the DNA replication mechanism, and simultaneously enumerate the aberrant expression of replication proteins as hallmark for various diseases, revealing their therapeutic potential for target therapy. Meanwhile, we also discuss current observations that the novel PTM of replication proteins in response to replication stress, which seems to be a promising strategy to eliminate diseases.

The EMT transcription factor ZEB1 governs a fitness-promoting but vulnerable DNA replication stress response

The DNA damage response (DDR) and epithelial-to-mesenchymal transition (EMT) are two crucial cellular programs in cancer biology. While the DDR orchestrates cell-cycle progression, DNA repair, and cell death, EMT promotes invasiveness, cellular plasticity, and intratumor heterogeneity. Therapeutic targeting of EMT transcription factors, such as ZEB1, remains challenging, but tumor-promoting DDR alterations elicit specific vulnerabilities. Using multi-omics, inhibitors, and high-content microscopy, we discover a chemoresistant ZEB1-high-expressing sub-population (ZEB1^hi) with co-rewired cell-cycle progression and proficient DDR across tumor entities. ZEB1 stimulates accelerated S-phase entry via CDK6, inflicting endogenous DNA replication stress. However, DDR buildups involving constitutive MRE11-dependent fork resection allow homeostatic cycling and enrichment of ZEB1^hi cells during transforming growth factor β (TGF-β)-induced EMT and chemotherapy. Thus, ZEB1 promotes G1/S transition to launch a progressive DDR benefitting stress tolerance, which concurrently manifests a targetable vulnerability in chemoresistant ZEB1^hi cells. Our study thus highlights the translationally relevant intercept of the DDR and EMT.

Targeting TGF-β signaling in the multiple myeloma microenvironment: Steering CARs and T cells in the right direction

Multiple myeloma (MM) remains a lethal hematologic cancer characterized by the expansion of transformed plasma cells within the permissive bone marrow (BM) milieu. The emergence of relapsed and/or refractory MM (RRMM) is provoked through clonal evolution of malignant plasma cells that harbor genomic, metabolic and proteomic perturbations. For most patients, relapsed disease remains a major cause of overall mortality. Transforming growth factors (TGFs) have pleiotropic effects that regulate myelomagenesis as well as the emergence of drug resistance. Moreover, TGF-β modulates numerous cell types present with the tumor microenvironment, including many immune cell types. While numerous agents have been FDA-approved over the past 2 decades and significantly expanded the treatment options available for MM patients, the molecular mechanisms responsible for drug resistance remain elusive. Multiple myeloma is uniformly preceded by a premalignant state, monoclonal gammopathy of unknown significance, and both conditions are associated with progressive deregulation in host immunity characterized by reduced T cell, natural killer (NK) cell and antigen-presenting dendritic cell (DC) activity. TGF-β promotes myelomagenesis as well as intrinsic drug resistance by repressing anti-myeloma immunity to promote tolerance, drug resistance and disease progression. Hence, repression of TGF-β signaling is a prerequisite to enhance the efficacy of current and future immunotherapeutics. Novel strategies that incorporate T cells that have been modified to express chimeric antigen receptor (CARs), T cell receptors (TCRs) and bispecific T cell engagers (BiTEs) offer promise to block TGF-β signaling, overcome chemoresistance and enhance anti-myeloma immunity. Here, we describe the effects of TGF-β signaling on immune cell effectors in the bone marrow and emerging strategies to overcome TGF-β-mediated myeloma growth, drug resistance and survival.

Biological Effects of Transforming Growth Factor Beta in Human Cholangiocytes

TGF-β is a cytokine implicated in multiple cellular responses, including cell cycle regulation, fibrogenesis, angiogenesis and immune modulation. In response to pro-inflammatory and chemotactic cytokines and growth factors, cholangiocytes prime biliary damage, characteristic of cholangiopathies and pathologies that affect biliary tree. The effects and signaling related to TGF-β in cholangiocyte remains poorly investigated. In this study, the cellular response of human cholangiocytes to TGF-β was examined. Wound-healing assay, proliferation assay and cell cycle analyses were used to monitor the changes in cholangiocyte behavior following 24 and 48 h of TGF-β stimulation. Moreover, proteomic approach was used to identify proteins modulated by TGF-β treatment. Our study highlighted a reduction in cholangiocyte proliferation and a cell cycle arrest in G0/G1 phase following TGF-β treatment. Moreover, proteomic analysis allowed the identification of four downregulated proteins (CaM kinase II subunit delta, caveolin-1, NipSnap1 and calumin) involved in Ca2+ homeostasis. Accordingly, Gene Ontology analysis highlighted that the plasma membrane and endoplasmic reticulum are the cellular compartments most affected by TGF-β. These results suggested that the effects of TGF-β in human cholangiocytes could be related to an imbalance of intracellular calcium homeostasis. In addition, for the first time, we correlated calumin and NipSnap1 to TGF-β signaling.

Protective Effect of Grape Seed Proanthocyanidins on Oxidative Damage of Chicken Follicular Granulosa Cells by Inhibiting FoxO1-Mediated Autophagy

A significant decrease in poultry egg production occurs due to ovarian aging and autophagy is one of the important factors of ovarian aging that is induced predominantly by oxidative stress. Increasing evidence showed potential roles of plant-derived grape seed proanthocyanidin (GSPs) in protecting ovarian granulosa cells (GCs) from oxidative damage, although the underlying mechanism is still unclear. Here we investigated the possible functions of autophagy involved in the preventive effect of GSPs on oxidative stress in the GCs of ovarian hierarchical follicles of laying chickens. The results showed that increased autophagy was observed in the aging hens (580-day-old, D580) compared with the peak-lay hens (D280). Treatment of GSPs significantly restored the elevated autophagy and decreased viability of cultured D280 chicken GCs that were elicited by hydrogen peroxide. GSPs also suppressed the increased autophagy in the natural aging hens. Similar to the effect of GSPs on GC viability, inhibition of autophagy also showed a protective effect on the decreased viability of GCs under oxidative damage. However, GSPs were not able to provide further protection in GCs that were pretreated with 3-methyladenine (an autophagy inhibitor). In addition to its promoting action on antioxidant capacity, treatment with GSPs increased survival of GCs from autophagy that was caused by oxidative stress through the FoxO1-related pathway. Inhibition of FoxO1 or activation of PI3K-Akt pathway by GSPs increased the confrontation of GCs to oxidative damage and decreased autophagy in GCs. In addition, activation of the SIRT1 signal inhibited the GCs autophagy that was caused by oxidative stress via GSPs-induced deacetylation of FoxO1. These results revealed a new mechanism of GSPs against oxidative stress of GCs via inhibiting FoxO1, which was probably a possible target for alleviating ovarian aging in laying poultry.

Transforming Growth Factor-Beta (TGF-β) Signaling in Cancer-A Betrayal Within

A ubiquitously expressed cytokine, transforming growth factor-beta (TGF-β) plays a significant role in various ongoing cellular mechanisms. The gain or loss-of-function of TGF-β and its downstream mediators could lead to a plethora of diseases includes tumorigenesis. Specifically, at the early onset of malignancy TGF-β act as tumour suppressor and plays a key role in clearing malignant cells by reducing the cellular proliferation and differentiation thus triggers the process of apoptosis. Subsequently, TGF-β at an advanced stage of malignancy promotes tumorigenesis by augmenting cellular transformation, epithelial-mesenchymal-transition invasion, and metastasis. Besides playing the dual roles, depending upon the stage of malignancy, TGF-β also regulates cell fate through immune and stroma components. This oscillatory role of TGF-β to fight against cancer or act as a traitor to collaborate and crosstalk with other tumorigenic signaling pathways and its betrayal within the cell depends upon the cellular context. Therefore, the current review highlights and understands the dual role of TGF-β under different cellular conditions and its crosstalk with other signaling pathways in modulating cell fate.

Interleukin-6 Induced Proliferation Is Attenuated by Transforming Growth Factor-β-Induced Signaling in Human Hepatocellular Carcinoma Cells

Hepatocellular carcinoma (HCC) is often associated with an inflammatory setting. A plethora of cytokines are secreted in this milieu, actively contributing to the progression of the disease; however, the extent of cytokine interaction and how it contributes to HCC development remains an enigma. In this regard, our analysis of available patient-derived data suggests that cytokines like interleukin-6 (IL-6) and transforming growth factor-beta (TGF-β) are enriched in HCC. We further analyzed the effect of these cytokines independently or in combination on HCC cells. Importantly, IL-6 was found to induce a STAT-3-dependent proliferation and mediate its pro-proliferative effects through activation and direct interaction with the p65 subunit of NFkB. Alternatively, TGF-β was found to induce a SMAD-dependent induction of epithelial to mesenchymal transition (EMT) coupled to growth arrest in these cells. Interestingly, the simultaneous addition of IL-6 and TGF-β failed to profoundly impact EMT markers but resulted in attenuation of IL-6-induced pro-proliferative effects. Analysis of the putative molecular mechanism revealed a decrease in IL-6 receptor (IL-6R) transcript levels, reduced expression of IL-6-induced STAT-3, and its nuclear localization upon addition of TGF-β along with IL-6. Consequently, a reduced p65 activation was also observed in combination treatment. Importantly, SMAD levels were unperturbed and the cells showed more TGF-β-like features under combination treatment. Finally, we observed that TGF-β resulted in enrichment of repressive chromatin mark (H3K27me3) coupled to growth arrest, while IL-6 induced an open chromatin signature (H3K4me3) associated with an enhanced expression of EZH2. Overall, for the first time, we show that TGF-β attenuates IL-6-induced effects by regulating the receptor level, downstream signaling, and the epigenome. Understanding the complex interactions between these cytokines can be imperative to a better understanding of the disease, and manipulation of cytokine balance can act as a prospective future therapeutic strategy.

Hyaluronic acid regulates heart valve interstitial cell contraction in fibrin-based scaffolds

Heart valve disease is associated with high morbidity and mortality worldwide resulting in hundreds of thousands of heart valve replacements each year. Tissue engineered heart valves (TEHVs) have the potential to overcome the major limitations of traditional replacement valves; however, leaflet retraction has led to the failure of TEHVs in preclinical studies. As native unmodified hyaluronic acid (HA) is known to promote healthy tissue development in native heart valves, we hypothesize that adding unmodified HA to fibrin-based scaffolds common to tissue engineering will reduce retraction by increasing cell-scaffold interactions and density of the scaffolds. Using a custom high-throughput culture system, we found that incorporating HA into millimeter-scale fibrin-based cell-populated scaffolds increases initial fiber diameter and cell-scaffold interactions, causing a cascade of mechanical, morphological, and cellular responses. These changes lead to higher levels of scaffold compaction and stiffness, increased cell alignment, and less bundling of fibrin fibers by the cells during culture. These effects significantly reduce scaffold retraction and total contractile force each by around 25%. These findings increase our understanding of how HA alters tissue remodeling and could inform the design of the next generation of tissue engineered heart valves to help reduce retraction. STATEMENT OF SIGNIFICANCE: Tissue engineered heart valves (TEHVs) have the potential to overcome the major limitations of traditional replacement valves; however, leaflet retraction induced by excessive myofibroblast activation has led to failure in preclinical studies. Developing valves are rich in hyaluronic acid (HA), which helps maintain a physiological environment for tissue remodeling without retraction. We hypothesized that adding unmodified HA to TEHVs would reduce retraction by increasing cell-scaffold interactions and density of the scaffolds. Using a high-throughput tissue culture platform, we demonstrate that HA incorporation into a fibrin-based scaffold can significantly reduce tissue retraction and total contractile force by increasing fiber bundling and altering cell-mediated matrix remodeling, therefore increasing gel density and stiffness. These finding increase our knowledge of native HA's effects within the extracellular matrix, and provide a new tool for TEHV design.

Retinoblastoma: from discovery to clinical management

The retinoblastoma gene (RB1) was the first tumour suppressor cloned; the role of its protein product (RB) as the principal driver of the G1 checkpoint in cell cycle control has been extensively studied. However, many other RB functions are continuously reported. Its role in senescence, DNA repair and apoptosis, among others, is indications of the significance of RB in a vast network of cellular interactions, explaining why RB loss or its malfunction is one of the leading causes of a large number of paediatric and adult cancers. RB was first reported in retinoblastoma, a common intraocular malignancy in the paediatric population worldwide. Currently, its diagnosis is clinical, and in nondeveloped countries, where the incidence is higher, it is performed in advanced stages of the disease, compromising the integrity of the eye and the patient's life. Even though new treatments are being continuously developed, enucleation is still a major choice due to the late disease stage diagnosis and treatments costs. Research into biomarkers is our best option to improve the chances of good results in the treatment and hopes of patients' good quality of life. Here, we recapitulated the history of the disease and the first treatments to put the advances in its clinical management into perspective. We also review the different functions of the protein and the progress in the search for biomarkers. It is clear that there is still a long way to go, but we should offer these children and their families a better way to deal with the disease with the community's effort.

Hsa-miR-186-5p regulates TGFβ signaling pathway through expression suppression of SMAD6 and SMAD7 genes in colorectal cancer

TGFβ signaling is a known pathway to be involved in colorectal cancer (CRC) progression and miRNAs play crucial roles by regulating different components of this pathway. Hence, finding the link between miRNAs and the pathway could be beneficial for CRC therapy. Array data indicated that miR-186-5p is a differentially expressed miRNA in colorectal Tumor/Normal tissues and bioinformatics tools predicted SMAD6/7 (inhibitory SMADs) as bona fide targets of this miRNA. Here, we intended to investigate the regulatory effect of the miR-186-5p expression on TGFβ signaling in CRC. Firstly, the miR-186-5p overexpression in HCT116 cells resulted in a significant reduction of SMAD6/7 expression, measured through RT-qPCR. Then, the direct interactions of miR-186-5p with SMAD6/7 3'UTRs were supported through dual luciferase assay. Furthermore, miR-186-5p overexpression suppressed proliferation, cell viability, and migration while, it increased apoptosis in CRC cells, assessed by cell cycle, MTT, scratch and Annexin V/PI apoptosis assays. Consistently, miR-186-5p overexpression resulted in reduced CyclinD1 protein using western blot, and also resulted in increased P21 and decreased c-Myc expression. Overall, these results introduced miR-186-5p as a cell cycle suppressor through downregulation of SMAD6/7 expression. Thus, miR-186-5p might be served as a novel tumor suppressive biomarker and therapeutic target in CRC treatment.

Quantitative Proteomic Analysis in Alveolar Type II Cells Reveals the Different Capacities of RAS and TGF-β to Induce Epithelial-Mesenchymal Transition

Alveolar type II (ATII) epithelial cells function as stem cells, contributing to alveolar renewal, repair and cancer. Therefore, they are a highly relevant model for studying a number of lung diseases, including acute injury, fibrosis and cancer, in which signals transduced by RAS and transforming growth factor (TGF)-β play critical roles. To identify downstream molecular events following RAS and/or TGF-β activation, we performed proteomic analysis using a quantitative label-free approach (LC-HDMS^E) to provide in-depth proteome coverage and estimates of protein concentration in absolute amounts. Data are available via ProteomeXchange with identifier PXD023720. We chose ATII^ER:KRASV12 as an experimental cell line in which RAS is activated by adding 4-hydroxytamoxifen (4-OHT). Proteomic analysis of ATII cells treated with 4-OHT or TGF-β demonstrated that RAS activation induces an epithelial–mesenchymal transition (EMT) signature. In contrast, under the same conditions, activation of TGF-β signaling alone only induces a partial EMT. EMT is a dynamic and reversible biological process by which epithelial cells lose their cell polarity and down-regulate cadherin-mediated cell–cell adhesion to gain migratory properties, and is involved in embryonic development, wound healing, fibrosis and cancer metastasis. Thus, these results could help to focus research on the identification of processes that are potentially driving EMT-related human disease.

Direct Regulation of DNA Repair by E2F and RB in Mammals and Plants: Core Function or Convergent Evolution?

Simple Summary

Retinoblastoma (RB) proteins and E2F transcription factors partner together to regulate the cell cycle in many eukaryotic organisms. In organisms that lack one or both of these proteins, other proteins have taken on the essential function of cell cycle regulation. RB and E2F also have important functions outside of the cell cycle, including DNA repair. This review summarizes the non-canonical functions of RB and E2F in maintaining genome integrity and raises the question of whether such functions have always been present or have evolved more recently.

Abstract

Members of the E2F transcription factor family regulate the expression of genes important for DNA replication and mitotic cell division in most eukaryotes. Homologs of the retinoblastoma (RB) tumor suppressor inhibit the activity of E2F factors, thus controlling cell cycle progression. Organisms such as budding and fission yeast have lost genes encoding E2F and RB, but have gained genes encoding other proteins that take on E2F and RB cell cycle-related functions. In addition to regulating cell proliferation, E2F and RB homologs have non-canonical functions outside the mitotic cell cycle in a variety of eukaryotes. For example, in both mammals and plants, E2F and RB homologs localize to DNA double-strand breaks (DSBs) and directly promote repair by homologous recombination (HR). Here, we discuss the parallels between mammalian E2F1 and RB and their Arabidopsis homologs, E2FA and RB-related (RBR), with respect to their recruitment to sites of DNA damage and how they help recruit repair factors important for DNA end resection. We also explore the question of whether this role in DNA repair is a conserved ancient function of the E2F and RB homologs in the last eukaryotic common ancestor or whether this function evolved independently in mammals and plants.

Circadian Dysregulation of the TGFβ/SMAD4 Pathway Modulates Metastatic Properties and Cell Fate Decisions in Pancreatic Cancer Cells

Impairment of circadian rhythms impacts carcinogenesis. SMAD4, a clock-controlled gene and central component of the TGFβ canonical pathway, is frequently mutated in pancreatic ductal adenocarcinoma (PDA), leading to decreased survival. Here, we used an in vitro PDA model of SMAD4-positive and SMAD4-negative cells to investigate the interplay between circadian rhythms, the TGFβ canonical signaling pathway, and its impact on tumor malignancy. Our data show that TGFβ1, SMAD3, SMAD4, and SMAD7 oscillate in a circadian fashion in SMAD4-positive PDA cells, whereas altering the clock impairs the mRNA dynamics of these genes. Furthermore, the expression of the clock genes DEC1, DEC2, and CRY1 varied depending on SMAD4 status. TGFβ pathway activation resulted in an altered clock, cell-cycle arrest, accelerated apoptosis rate, enhanced invasiveness, and chemosensitivity. Our data suggest that the impact of TGFβ on the clock is SMAD4-dependent, and S MAD3, SMAD4, DEC1, and CRY1 involved in this cross-talk affect PDA patient survival.

Hsa-miR-587 Regulates TGFβ/SMAD Signaling and Promotes Cell Cycle Progression

OBJECTIVE

Transforming growth factor beta/single mothers against decapentaplegic (TGFβ/SMAD) signaling pathway plays important roles in various biological processes. It acts as a tumor suppressor during the early stages of cancer progression. Discovering the regulators of this pathway provides important options for therapeutic strategies. Here, we searched for candidate microRNAs (miRNAs) that potentially target the critical components of the TGFβ signaling pathway.

MATERIALS AND METHODS

In the current experimental study, we first predicted miRNAs that target TGFβ components using a bioinformatics software. After that, quantitative real-time polymerase chain reaction (RT-qPCR) was used to detect the expression of miR-587, TGFBR2, SMAD4, p21, CCND1 and c-MYC genes in transfected HEK293T and HCT116 cells. Dual Luciferase assay was performed to analyze the interactions between miRNAs and the target genes. Propidium iodide flow cytometry was used to determine cell cycle progression in HEK293T and HCT116 cells under hsa-miR-587 (miR-587) overexpression circumstances.

RESULTS

Multiple miRNA responsive elements (MREs) were predicted for miR-587 within the 3'UTRs of the TGFBR2 and SMAD4 genes. Overexpression of miR-587 in HEK293T and HCT116 cells resulted in downregulation of TGFBR2 and SMAD4 genes. In addition, a downstream target gene of TGFβ/SMAD signaling, P21, was significantly downregulated in the HCT116 cells overexpressing miR-587. Dual luciferase assay analysis provided evidence that there is a direct interaction between miR-587 and the 3'UTR sequences of TGFBR2 and SMAD4 genes. Moreover, miR-587 overexpression in HEK293T and HCT116 cells resulted in reducing the SubG1 cell populations in both cell lines, as detected by flow cytometry.

CONCLUSION

Altogether, our data revealed an important role for miR-587 in regulating TGFβ/SMAD signaling and promoting cell cycle progression. These characteristics suggest that miR-587 is an important candidate for cancer therapy research.

Myc and the Replicative CMG Helicase: The Creation and Destruction of Cancer: Myc Over-Activation of CMG Helicases Drives Tumorigenesis and Creates a Vulnerability in CMGs for Therapeutic Intervention

Myc-driven tumorigenesis involves a non-transcriptional role for Myc in over-activating replicative Cdc45-MCM-GINS (CMG) helicases. Excessive stimulation of CMG helicases by Myc mismanages CMG function by diminishing the number of reserve CMGs necessary for fidelity of DNA replication and recovery from replicative stresses. One potential outcome of these events is the creation of DNA damage that alters genomic structure/function, thereby acting as a driver for tumorigenesis and tumor heterogeneity. Intriguingly, another potential outcome of this Myc-induced CMG helicase over-activation is the creation of a vulnerability in cancer whereby tumor cells specifically lack enough unused reserve CMG helicases to recover from fork-stalling drugs commonly used in chemotherapy. This review provides molecular and clinical support for this provocative hypothesis that excessive activation of CMG helicases by Myc may not only drive tumorigenesis, but also confer an exploitable "reserve CMG helicase vulnerability" that supports developing innovative CMG-focused therapeutic approaches for cancer management.

G-quadruplexes in fibrotic scars may open new therapeutic avenues for wound healing

Read the Original article at https://doi.org/10.1002/1873-3468.13658.

Myc-driven chromatin accessibility regulates Cdc45 assembly into CMG helicases

Myc-driven tumorigenesis involves a non-transcriptional role for Myc in over-activating replication origins. We show here that the mechanism underlying this process involves a direct role for Myc in activation of Cdc45-MCM-GINS (CMG) helicases at Myc-targeted sites. Myc induces decondensation of higher-order chromatin at targeted sites and is required for chromatin access at a chromosomal origin. Myc-driven chromatin accessibility promotes Cdc45/GINS recruitment to resident MCMs, and activation of CMGs. Myc-Box II, which is necessary for Myc-driven transformation, is required for Myc-induced chromatin accessibility, Cdc45/GINS recruitment, and replication stimulation. Myc interactors GCN5, Tip60, and TRRAP are essential for chromatin unfolding and recruitment of Cdc45, and co-expression of GCN5 or Tip60 with MBII-deficient Myc rescues these events and promotes CMG activation. Finally, Myc and Cdc45 interact and physiologic conditions for CMG assembly require the functions of Myc, MBII, and GCN5 for Cdc45 recruitment and initiation of DNA replication.

Discovery of Novel Bromophenol-Thiosemicarbazone Hybrids as Potent Selective Inhibitors of Poly(ADP-ribose) Polymerase-1 (PARP-1) for Use in Cancer

Poly(ADP-ribose) polymerase-1 (PARP-1) is a new potential target for anticancer drug discovery. A series of bromophenol-thiosemicarbazone hybrids as PARP-1 inhibitors were designed, synthesized, and evaluated for their antitumor activities. Among them, the most promising compound, 11, showed excellent selective PARP-1 inhibitory activity (IC₅₀ = 29.5 nM) over PARP-2 (IC₅₀ > 1000 nM) and potent anticancer activities toward the SK-OV-3, Bel-7402 and HepG2 cancer cell lines (IC₅₀ = 2.39, 5.45, and 4.60 μM), along with inhibition of tumor growth in an in vivo SK-OV-3 cell xenograft model. Further study demonstrated that compound 11 played an antitumor role through multiple anticancer mechanisms, including the induction of apoptosis and cell cycle arrest, cellular accumulation of DNA double-strand breaks, DNA repair alterations, inhibition of H₂O₂-triggered PARylation, antiproliferative effects via the production of cytotoxic reactive oxygen species, and autophagy. In addition, compound 11 displayed good pharmacokinetic characteristics and favorable safety. These observations demonstrate that compound 11 may serve as a lead compound for the discovery of new anticancer drugs.

Cancer Biomarkers for Integrative Oncology

PURPOSE OF REVIEW

There has been an increasing interest in using complementary and alternative medicine (CAM) approaches to treat cancer. It is therefore relevant and timely to determine if CAM biomarkers can be identified and developed to guide cancer diagnosis and treatment. Herein, we review the status of cancer biomarkers in CAM research and treatment to stimulate further research in this area.

RECENT FINDINGS

Studies on promising anti-cancer natural products, such as PHY906, honokiol, bryostatin-1, and sulforaphane have demonstrated the existence of potential cancer biomarker(s). Additional studies are required to further develop and ultimately validate these biomarkers that can predict clinical activity of the anti-cancer natural products used alone or in combination with chemotherapeutic agents. A systematic approach is needed to identify and develop CAM treatment associated biomarkers and to define their role in facilitating clinical decision-making. The expectation is to use these biomarkers in determining potential options for CAM treatment, examining treatment effects and toxicity and/or clinical efficacy in patients with cancer.

Conditioned Medium from Human Amnion-Derived Mesenchymal Stem Cells Regulates Activation of Primary Hepatic Stellate Cells

Mesenchymal stem cells (MSCs), or multipotent mesenchymal stromal cells, are present in almost all organs and tissues, including the amnion. Human amnion-derived mesenchymal stem cell (hAMSC) transplantation has been reported to ameliorate liver fibrosis in animal models. However, the mechanism for the prevention of liver fibrosis is poorly understood. In this study, we investigated the effects, and underlying mechanisms, of a conditioned medium obtained from hAMSC cultures (hAMSC-CM) on a primary culture of rat hepatic stellate cells (HSCs). We observed that in routine culture, hAMSC-CM in HSCs significantly inhibited the expression of alpha-smooth muscle actin (α-SMA), an activation marker of HSCs, and the production of collagen type 1 (COL1), a dominant component of the extracellular matrix (ECM) in the culture medium. In addition, hAMSC-CM upregulated the expression of ECM degradation-related genes, such as metalloproteinase- (Mmp-) 2, Mmp-9, Mmp-13, and tissue inhibitor of metalloproteinase- (Timp-) 1; however, it did not affect the expression of collagen type 1α1 (Col1a1). These regulatory effects on HSCs were concentration-dependent. A cell proliferation assay indicated that hAMSC-CM significantly suppressed HSC proliferation and downregulated the expression of cyclin B (Ccnb), a proliferation-related gene. Transforming growth factor-beta (TGF-β) treatment further activated HSCs and hAMSC-CM significantly inhibited the upregulation of α-Sma and Col1a1 induced by TGF-β. These findings demonstrated that hAMSC-CM can modulate HSC function via secretory factors and provide a plausible explanation for the protective role of hAMSCs in liver fibrosis.

TGFβ1 Cell Cycle Arrest Is Mediated by Inhibition of MCM Assembly in Rb-Deficient Conditions

Transforming growth factor β1 (TGFβ1) is a potent inhibitor of cell growth that targets gene-regulatory events, but also inhibits the function of CDC45-MCM-GINS helicases (CMG; MCM, Mini-Chromosome Maintenance; GINS, Go-Ichi-Ni-San) through multiple mechanisms to achieve cell-cycle arrest. Early in G₁, TGFβ1 blocks MCM subunit expression and suppresses Myc and Cyclin E/Cdk2 activity required for CMG assembly, should MCMs be expressed. Once CMGs are assembled in late-G₁, TGFβ1 blocks CMG activation using a direct mechanism involving the retinoblastoma (Rb) tumor suppressor. Here, in cells lacking Rb, TGFβ1 does not suppress Myc, Cyclin E/Cdk2 activity, or MCM expression, yet growth arrest remains intact and Smad2/3/4-dependent. Such arrest occurs due to inhibition of MCM hexamer assembly by TGFβ1, which is not seen when Rb is present and MCM subunit expression is normally blocked by TGFβ1. Loss of Smad expression prevents TGFβ1 suppression of MCM assembly. Mechanistically, TGFβ1 blocks a Cyclin E-Mcm7 molecular interaction required for MCM hexamer assembly upstream of CDC10-dependent transcript-1 (CDT1) function. Accordingly, overexpression of CDT1 with an intact MCM-binding domain abrogates TGFβ1 arrest and rescues MCM assembly. The ability of CDT1 to restore MCM assembly and allow S-phase entry indicates that, in the absence of Rb and other canonical mediators, TGFβ1 relies on inhibition of Cyclin E-MCM7 and MCM assembly to achieve cell cycle arrest. IMPLICATIONS: These results demonstrate that the MCM assembly process is a pivotal target of TGFβ1 in eliciting cell cycle arrest, and provide evidence for a novel oncogenic role for CDT1 in abrogating TGFβ1 inhibition of MCM assembly.

Enhanced development of mouse single blastomeres into blastocysts via the simultaneous inhibition of TGF-β and ERK pathways in microdroplet culture

Optimization of an in vitro culture that supports blastocyst (BL) development from single blastomeres (SBs) is essential to generate additional embryos for farm animals and humans and unravel the mechanisms that underlie totipotency. In this study, we have examined BL development from SBs that were derived from 2-cell and 4-cell mouse embryos in different media. Moreover, BLs were assessed for inner cell mass (ICM) by staining with Oct4. We found that BL development was improved in a lower volume of medium (1 µL) compared with a higher volume (5 µL). Furthermore, the supplementation of medium with the inhibitors of ERK1/2 and TGFβ (R2i) signaling pathways in 1 µL droplets of T6 medium improved BL development. The co-culture of SBs with intact embryos in the presence of R2i showed more BL development and ICM to trophectoderm cell number ratio in comparison with SB culture and SB group culture. We also observed reduced total cell number, ICM, and trophectoderm cell numbers in all of the SB culture conditions versus intact embryo development. These findings might facilitate the successful generation of additional embryos for biomedical applications and elucidate the mechanisms that underlie totipotency.

RACK1 promotes lung cancer cell growth via an MCM7/RACK1/ Akt signaling complex

MCM7, a member of the miniature chromosome maintenance (MCM) protein family, is crucial for the initiation of DNA replication and proliferation in eukaryotic cells. In this report, we demonstrate that RACK1 regulates cell growth and cell cycle progression in human non-small-cell lung cancer by mediating MCM7 phosphorylation through an MCM7/RACK1/Akt signaling complex. RACK1 functions as a central scaffold that brings Akt into physical proximity with MCM7. Overexpression of RACK1 increases interactions between Akt and MCM7 and promotes Akt-dependent MCM7 phosphorylation, which in turn increases MCM7 binding to chromatin and MCM complex formation. Together, these changes promote DNA replication and cell proliferation. Our findings reveal a novel signaling pathway that regulates growth in non-small cell lung cancer.

Safer approaches to therapeutic modulation of TGF-β signaling for respiratory disease

The transforming growth factor (TGF)-β cytokines play a central role in development and progression of chronic respiratory diseases. TGF-β overexpression in chronic inflammation, remodeling, fibrotic process and susceptibility to viral infection is established in the most prevalent chronic respiratory diseases including asthma, COPD, lung cancer and idiopathic pulmonary fibrosis. Despite the overwhelming burden of respiratory diseases in the world, new pharmacological therapies have been limited in impact. Although TGF-β inhibition as a therapeutic strategy carries great expectations, the constraints in avoiding compromising the beneficial pleiotropic effects of TGF-β, including the anti-proliferative and immune suppressive effects, have limited the development of effective pharmacological modulators. In this review, we focus on the pathways subserving deleterious and beneficial TGF-β effects to identify strategies for selective modulation of more distal signaling pathways that may result in agents with improved safety/efficacy profiles. Adverse effects of TGF-β inhibitors in respiratory clinical trials are comprehensively reviewed, including those of the marketed TGF-β modulators, pirfenidone and nintedanib. Precise modulation of TGF-β signaling may result in new safer therapies for chronic respiratory diseases.

The impact of Mir-9 regulation in normal and malignant hematopoiesis

MicroRNA-9 (MiR-9) dysregulation has been observed in various cancers. Recently, MiR-9 is considered to have a part in hematopoiesis and hematologic malignancies. However, its importance in blood neoplasms is not yet well defined. Thus, this study was conducted in order to assess the significance of MiR-9 role in the development of hematologic neoplasia, prognosis, and treatment approaches. We have shown that a large number of MiR-9 targets (such as FOXOs, SIRT1, CCND1, ID2, CCNG1, Ets, and NFkB) play essential roles in leukemogenesis and that it is overexpressed in different leukemias. Our findings indicated MiR-9 downregulation in a majority of leukemias. However, its overexpression was reported in patients with dysregulated MiR-9 controlling factors (such as MLLr). Additionally, prognostic value of MiR-9 has been reported in some types of leukemia. This study generally emphasizes on the critical role of MiR-9 in hematologic malignancies as a prognostic factor and a therapeutic target.

Lamin B2 binding to minichromosome maintenance complex component 7 promotes non-small cell lung carcinogenesis

We investigated the role of lamin B2 in non-small cell lung cancer (NSCLC). We detected higher lamin B2 expression in 20 NSCLC tumor tissues obtained from The Cancer Genome Atlas than in adjacent normal lung tissues. LMNB2-RNAi knockdown in A549 and H1299 NSCLC cells inhibited colony formation, cell proliferation and G1-S cell cycle progression while increasing apoptosis. LMNB2 overexpression had the opposite effects. Tumor xenograft experiments showed diminished tumor growth with LMNB2 knockdown H1299 cells than with controls. Yeast two-hybrid studies revealed minichromosome maintenance complex component 7 (MCM7) to be a binding partner of lamin B2, which was confirmed by co-immunoprecipitation and co-localization studies. Lamin B2 binding enhanced DNA binding and helicase activities of MCM7. Deletion analysis with MCM7-N, MCM7-M or MCM7-C mutant proteins showed that lamin B2 binds to the C-terminus of MCM7, and competes with the binding of the tumor suppressor retinoblastoma (RB) protein. Immunohistochemical analysis of 150 NSCLC patient samples revealed that both lamin B2 and MCM7 levels positively correlated with histological grade and tumor TNM stage. Moreover, high lamin B2 and MCM7 levels correlated with shorter overall survival of NSCLC patients. In sum, these results show that lamin B2 interaction with MCM7 promotes NSCLC progression.

A microRNA signature of response to erlotinib is descriptive of TGFβ behaviour in NSCLC

Our previous work identified a 13-gene miRNA signature predictive of response to the epidermal growth factor receptor (EGFR) inhibitor, erlotinib, in Non-Small Cell Lung Cancer cell lines. Bioinformatic analysis of the signature showed a functional convergence on TGFβ canonical signalling. We hypothesized that TGFβ signalling controls expression of the miRNA genes comprising an erlotinib response signature in NSCLC. Western analysis revealed that TGFβ signalling via Smad2/3/4 occurred differently between erlotinib-resistant A549 and erlotinib- sensitive PC9 cells. We showed that TGFβ induced an interaction between Smad4 and putative Smad Binding Elements in PC9. However, qRT-PCR analysis showed that endogenous miR-140/141/200c expression changes resulted from time in treatments, not the treatments themselves. Moreover, flow cytometry indicated that cells exited the cell cycle in the same manner. Taken together these data indicated that the miRNA comprising the signature are likely regulated by the cell cycle rather than by TGFβ. Importantly, this work revealed that TGFβ did not induce EMT in PC9 cells, but rather TGFβ-inhibition induced an EMT-intermediate. These data also show that growth/proliferation signals by constitutively-activated EGFR may rely on TGFβ and a possible relationship between TGFβ and EGFR signalling may prevent EMT progression in this context rather than promote it.

Breviscapine (BVP) inhibits prostate cancer progression through damaging DNA by minichromosome maintenance protein-7 (MCM-7) modulation

Naturally occurring compounds are reported as effective candidates for prevention and treatment of various cancers. Breviscapine (BVP) is a mixture of flavonoid glycosides, derived from the Chinese herbs. Previous researches have indicated that BVP has comprehensive pharmacological functions. However, little is known about whether BVP has preventive effects on human prostate cancer. Here, we attempted to explore if BVP inhibits human prostate cancer in vitro and in vivo in a comprehensive manner. We found that BVP triggered cytotoxicity in prostate cancer cell lines dose-dependently. BVP-induced DNA damage caused the cell cycle arrest and apoptosis and further induced cell death. High expression of MCM-7 was reduced in BVP-treated cancer cells and tumor tissues, and also the DNA damage response marker of γH2AX is down-regulated by BVP, associated with MCM-7 expression through regulating retinoblastoma protein (Rb) and checkpoint control proteins expression. Additionally, BVP induced apoptotic response in prostate cancer cells and tumors via activating Caspase-3 and PARP. In vivo studies indicated that BVP impeded tumor growth in xenograft animal models. In conclusion, our data indicates that breviscapine (BVP) can be further explored for its potential, which might be used in human prostate cancer therapeutics.

Multiple molecular interactions redundantly contribute to RB-mediated cell cycle control

Background

The G1-S phase transition is critical to maintaining proliferative control and preventing carcinogenesis. The retinoblastoma tumor suppressor is a key regulator of this step in the cell cycle.

Results

Here we use a structure–function approach to evaluate the contributions of multiple protein interaction surfaces on pRB towards cell cycle regulation. SAOS2 cell cycle arrest assays showed that disruption of three separate binding surfaces were necessary to inhibit pRB-mediated cell cycle control. Surprisingly, mutation of some interaction surfaces had no effect on their own. Rather, they only contributed to cell cycle arrest in the absence of other pRB dependent arrest functions. Specifically, our data shows that pRB–E2F interactions are competitive with pRB–CDH1 interactions, implying that interchangeable growth arrest functions underlie pRB’s ability to block proliferation. Additionally, disruption of similar cell cycle control mechanisms in genetically modified mutant mice results in ectopic DNA synthesis in the liver.

Conclusions

Our work demonstrates that pRB utilizes a network of mechanisms to prevent cell cycle entry. This has important implications for the use of new CDK4/6 inhibitors that aim to activate this proliferative control network.

Confluence-dependent resistance to cisplatin in lung cancer cells is regulated by transforming growth factor-beta

PURPOSE OF THE STUDY

Confluence-dependent resistance (CDR) is a phenomenon in which the efficacy of anti-cancer agents decreases when cell density increases. CDR in lung cancer has never been reported. The purpose of this study is to investigate if CDR can occur in NSCLC cells and to find a role for transforming growth factor (TGF)-β as a mechanism of CDR.

MATERIALS AND METHODS

Non-small cell lung cancer (NSCLC) cell lines A549 and H2228 were exposed to cisplatin in a variety of cell density conditions. RNA interference targeting TGF-β receptor I was performed to silence the TGF-β pathway.

RESULTS

CDR to cisplatin was induced in NSCLC cells, whereas CDR to crizotinib, an inhibitor of activin receptor-like kinase, was not observed. During confluent conditions, the TGF-β1 concentration in the culture medium was the highest. Exogenous TGF-β1 inhibited cell proliferation and reduced sensitivity to cisplatin. Inhibition of the TGF-β pathway increased in terms of sensitivity to cisplatin at confluency.

CONCLUSIONS

CDR to cisplatin can occur in NSCLC cells, and the TGF-β pathway is associated with the regulation of CDR.

Minichromosome maintenance protein 7 as prognostic marker of tumor aggressiveness in pituitary adenoma patients

BACKGROUND

Ki-67 labeling index (LI) is currently regarded as a useful prognostic marker of pituitary adenoma (PA) clinical behavior, although its relevance as a reliable clinical indicator is far from being universally accepted, since both validations and criticisms are found in the literature. Minichromosome maintenance 7 (MCM7), a cell-cycle regulator protein, has been recently proposed as a marker of tumor aggressiveness in tumors from many sites, including the CNS. Therefore, we evaluated MCM7, in comparison to Ki-67, as a potential marker of clinical outcome in PA.

DESIGN AND METHODS

In this single-institution retrospective study, 97 patients with PA (23 ACTH, 12 GH, 29 PRL, 10 FSH/LH, and 23 non-secreting adenomas) were recruited and the prognostic value of both MCM7 and Ki-67 was evaluated by immunohistochemical techniques. In addition, p53 nuclear expression and mitotic index were also evaluated.

RESULTS

Twenty-six of the 97 PA patients recurred during the follow-up period. Cox's regression analysis showed that high nuclear expression of MCM7 LI, unlike Ki-67 LI, was directly associated with a higher (7.7-fold) risk of recurrence/progression. Kaplan-Meier analysis of recurrence/progression-free survival curves revealed that patients with high MCM7 LI (≥15%) had a shorter recurrence/progression-free survival than those with low MCM7 LI (<15%). Moreover, among patients with invasive tumors, high MCM7 LI identified those with the highest risk of recurrence/progression.

CONCLUSIONS

Data from this study suggest that MCM7 is a prognostic marker of clinical outcome in PA patients, more reliable and informative than Ki-67.

DMSO Enhances TGF-β Activity by Recruiting the Type II TGF-β Receptor From Intracellular Vesicles to the Plasma Membrane

Dimethyl sulfoxide (DMSO) is used to treat many diseases/symptoms. The molecular basis of the pharmacological actions of DMSO has been unclear. We hypothesized that DMSO exerts some of these actions by enhancing TGF-β activity. Here we show that DMSO enhances TGF-β activity by ∼3-4-fold in Mv1Lu and NMuMG cells expressing Smad-dependent luciferase reporters. In Mv1Lu cells, DMSO enhances TGF-β-stimulated expression of P-Smad2 and PAI-1. It increases cell-surface expression of TGF-β receptors (TβR-I and/or TβR-II) by ∼3-4-fold without altering their cellular levels as determined by (125) I-labeled TGF-β-cross-linking/Western blot analysis, suggesting the presence of large intracellular pools in these cells. Sucrose density gradient ultracentrifugation/Western blot analysis reveals that DMSO induces recruitment of TβR-II (but not TβR-I) from its intracellular pool to plasma-membrane microdomains. It induces more recruitment of TβR-II to non-lipid raft microdomains than to lipid rafts/caveolae. Mv1Lu cells transiently transfected with TβR-II-HA plasmid were treated with DMSO and analyzed by indirect immunofluoresence staining using anti-HA antibody. In these cells, TβR-II-HA is present as a vesicle-like network in the cytoplasm as well as in the plasma membrane. DMSO causes depletion of TβR-II-HA-containing vesicles from the cytoplasm and co-localization of TβR-II-HA and cveolin-1 at the plasma membrane. These results suggest that DMSO, a fusogenic substance, enhances TGF-β activity presumably by inducing fusion of cytoplasmic vesicles (containing TβR-II) and the plasma membrane, resulting in increased localization of TβR-II to non-lipid raft microdomains where canonical signaling occurs. Fusogenic activity of DMSO may play a pivotal role in its pharmacological actions involving membrane proteins with large cytoplasmic pools. J. Cell. Biochem. 117: 1568-1579, 2016. © 2015 Wiley Periodicals, Inc.

The N Terminus of the Retinoblastoma Protein Inhibits DNA Replication via a Bipartite Mechanism Disrupted in Partially Penetrant Retinoblastomas

The N-terminal domain of the retinoblastoma (Rb) tumor suppressor protein (RbN) harbors in-frame exon deletions in partially penetrant hereditary retinoblastomas and is known to impair cell growth and tumorigenesis. However, how such RbN deletions contribute to Rb tumor- and growth-suppressive functions is unknown. Here we establish that RbN directly inhibits DNA replication initiation and elongation using a bipartite mechanism involving N-terminal exons lost in cancer. Specifically, Rb exon 7 is necessary and sufficient to target and inhibit the replicative CMG helicase, resulting in the accumulation of inactive CMGs on chromatin. An independent N-terminal loop domain, which forms a projection, specifically blocks DNA polymerase α (Pol-α) and Ctf4 recruitment without affecting DNA polymerases ε and δ or the CMG helicase. Individual disruption of exon 7 or the projection in RbN or Rb, as occurs in inherited cancers, partially impairs the ability of Rb/RbN to inhibit DNA replication and block G1-to-S cell cycle transit. However, their combined loss abolishes these functions of Rb. Thus, Rb growth-suppressive functions include its ability to block replicative complexes via bipartite, independent, and additive N-terminal domains. The partial loss of replication, CMG, or Pol-α control provides a potential molecular explanation for how N-terminal Rb loss-of-function deletions contribute to the etiology of partially penetrant retinoblastomas.

Proton irradiation impacts age-driven modulations of cancer progression influenced by immune system transcriptome modifications from splenic tissue

Age plays a crucial role in the interplay between tumor and host, with additional impact due to irradiation. Proton irradiation of tumors induces biological modulations including inhibition of angiogenic and immune factors critical to 'hallmark' processes impacting tumor development. Proton irradiation has also provided promising results for proton therapy in cancer due to targeting advantages. Additionally, protons may contribute to the carcinogenesis risk from space travel (due to the high proportion of high-energy protons in space radiation). Through a systems biology approach, we investigated how host tissue (i.e. splenic tissue) of tumor-bearing mice was altered with age, with or without whole-body proton exposure. Transcriptome analysis was performed on splenic tissue from adolescent (68-day) versus old (736-day) C57BL/6 male mice injected with Lewis lung carcinoma cells with or without three fractionations of 0.5 Gy (1-GeV) proton irradiation. Global transcriptome analysis indicated that proton irradiation of adolescent hosts caused significant signaling changes within splenic tissues that support carcinogenesis within the mice, as compared with older subjects. Increases in cell cycling and immunosuppression in irradiated adolescent hosts with CDK2, MCM7, CD74 and RUVBL2 indicated these were the key genes involved in the regulatory changes in the host environment response (i.e. the spleen). Collectively, these results suggest that a significant biological component of proton irradiation is modulated by host age through promotion of carcinogenesis in adolescence and resistance to immunosuppression, carcinogenesis and genetic perturbation associated with advancing age.