Ras-induced ROS upregulation affecting cell proliferation is connected with cell type-specific alterations of HSF1/SESN3/p21Cip1/WAF1 pathways

Krüppel-like factor 6 involvement in the endoplasmic reticulum homeostasis of extravillous trophoblasts

INTRODUCTION

Trophoblast homeostasis and differentiation require a proper endoplasmic reticulum (ER) function. The Krüppel-like factor-6 (KLF6) transcription factor modulates trophoblast migration, differentiation, and reactive oxygen species (ROS) production. Since ROS may impact on ER homeostasis, we assessed whether downregulation of KLF6 altered the unfolded protein response (UPR) and cellular process associated with ER homeostasis.

MATERIALS AND METHODS

Protein and RNA expression were analyzed by Western blot and qRT-PCR, respectively, in extravillous trophoblast HTR-8/SVneo cells silenced for KLF6. Apoptosis was detected by flow cell cytometry using Annexin V Apoptosis Detection Kit. Protein trafficking was assessed by confocal microscopy of a reporter fluorescent protein whose release from the ER was synchronized.

RESULTS

KLF6 downregulation reduced the expression of BiP, the master regulator of the UPR, at protein, mRNA, and pre-mRNA levels. Ire1α protein, XBP1 splicing, and DNAJB9 mRNA levels were also reduced in KLF6-silenced cells. Instead, PDI, Ero1α, and the p-eIF2α/eIF2α ratio as well as autophagy and proteasome dependent protein degradation remained unchanged while intracellular trafficking was increased. Under thapsigargin-induced stress, KLF6 silencing impaired BiP protein and mRNA expression increase, as well as the activation of the Ire1α pathway, but it raised the p-eIF2α/eIF2α ratio and CHOP protein levels. Nevertheless, apoptosis was not increased.

DISCUSSION

Results provide the first evidence of KLF6 as a modulator of the UPR components. The increase in protein trafficking and protection from apoptosis, observed in KLF6-silenced cells, are consistent with its role in extravillous trophoblast migration and differentiation.

NPRL2 is required for proliferation of oncogenic Ras-transformed bronchial epithelial cells

Nitrogen permease regulator-like 2 (NPRL2/TUSC4) is known to exert both tumor-suppressing and oncogenic effects in different types of cancers, suggesting that its actions are context dependent. Here, we delineated the molecular and functional effects of NPRL2 in malignantly transformed bronchial epithelial cells. To do so, we depleted NPRL2 in oncogenic HRas-transduced and malignantly transformed human bronchial epithelial (BEAS2B), Ras-AI-T2 cells. Intriguingly, depletion of NPRL2 in these cells induced activation of mTORC1 downstream signaling, inhibited autophagy, and impaired Ras-AI-T2 cell proliferation both in vitro and in vivo. These results suggest that NPRL2 is required for oncogenic HRas-induced cell transformation. Depletion of NPRL2 increased levels of the DNA damage marker γH2AX, the cell cycle inhibitors p21 and p27, and the apoptosis marker cleaved-PARP. These NPRL2-depleted cells first accumulated at G1 and G2, and later exhibited signs of mitotic catastrophe, which implied that NPRL2 depletion may be detrimental to oncogenic HRas-transformed cells. Additionally, NPRL2 depletion reduced heat shock factor 1/heat shock element- and NRF2/antioxidant response element-directed luciferase reporter activities in Ras-AI-T2 cells, indicating that NPRL2 depletion led to the suppression of two key cytoprotective processes in oncogenic HRas-transformed cells. Overall, our data suggest that oncogenic HRas-transduced and malignantly transformed cells may depend on NPRL2 for survival and proliferation, and depletion of NPRL2 also induces a stressed state in these cells.

Genetic overlap and causal inferences between diet-derived antioxidants and small-cell lung cancer

Several studies have reported that antioxidants exert both preventive and inhibitory effects against tumors. However, their causal effects on small-cell lung cancer (SCLC) remain controversial. Herein, we explored the causal effects of 6 antioxidants on SCLC by combining a genome-wide association study database and the Mendelian randomization (MR) approach. We obtained antioxidant genetic variance data for 6 exposure factors: carotene, vitamin A (retinol), selenium, zinc, vitamin C, and vitamin E, from the genome-wide association study database. The instrumental variables for exposure factors and SCLC outcomes were integrated by screening instrumental variables and merging data. Two-sample MR was used to analyze the causal relationship between exposure and outcomes. Finally, we examined the heterogeneity and horizontal pleiotropy of the MR analysis by performing multiple sensitivity analyses. We found a causal relationship between carotene and SCLC using two-sample MR analysis and sensitivity analysis (P = .02; odds ratio = 0.73; 95% confidence interval: 0.55-0.95). In contrast, there was no causal relationship between other examined antioxidants and SCLC. We found that diet-derived circulating antioxidants could afford protection against SCLC, and carotene is the causal protective factor against SCLC.

Whole-exome sequencing identified recurrent and novel variants in benzene-induced leukemia

BACKGROUND

Genome-wide sequencing may extensively identify potential pathogenic variants, which helps to understand mechanisms of tumorigenesis, but such study has not been reported in benzene-induced leukemia (BIL).

METHODS

We recruited 10 BIL patients and conducted the whole-exome sequencing on their peripheral blood samples. The obtained sequencing data were screened for potential pathogenic and novel variants, then the variants-located genes were clustered to identify cancer-related pathways. Shared or recurrent variants among the BIL cases were also identified and evaluated for their potential functional impact.

RESULTS

We identified 48,802 variants in exons in total, 97.3% of which were single nucleotide variants. After filtering out variants with minor allele frequency ≥ 1%, we obtained 8667 potentially pathogenic variants, of which 174 were shared by all the BIL cases. The identified variants located in genes that could be significantly enriched into certain cancer-related pathways such as PI3K-AKT signaling pathway and Ras signaling pathway. We also identified 1010 novel variants with no record in the Genome Aggregation Database and in dbSNP, and one of them was shared by 90% cases. The recurrent and novel variant caused a missense mutation in SESN3.

CONCLUSIONS

We examined variations of the whole exome in BIL patients for the first time. The commonly shared variants implied a relation with BIL, and the recurrent and novel variant might be specifically related to BIL. The related variants may help unravel the carcinogenic mechanisms of BIL.

Morphological and Molecular Responses of Lateolabrax maculatus Skeletal Muscle Cells to Different Temperatures

Temperature strongly modulates muscle development and growth in ectothermic teleosts; however, the underlying mechanisms remain largely unknown. In this study, primary cultures of skeletal muscle cells of Lateolabrax maculatus were conducted and reared at different temperatures (21, 25, and 28 °C) in both the proliferation and differentiation stages. CCK-8, EdU, wound scratch and nuclear fusion index assays revealed that the proliferation, myogenic differentiation, and migration processes of skeletal muscle cells were significantly accelerated as the temperature raises. Based on the GO, GSEA, and WGCNA, higher temperature (28 °C) induced genes involved in HSF1 activation, DNA replication, and ECM organization processes at the proliferation stage, as well as HSF1 activation, calcium activity regulation, myogenic differentiation, and myoblast fusion, and sarcomere assembly processes at the differentiation stage. In contrast, lower temperature (21 °C) increased the expression levels of genes associated with DNA damage, DNA repair and apoptosis processes at the proliferation stage, and cytokine signaling and neutrophil degranulation processes at the differentiation stage. Additionally, we screened several hub genes regulating myogenesis processes. Our results could facilitate the understanding of the regulatory mechanism of temperature on fish skeletal muscle growth and further contribute to utilizing rational management strategies and promoting organism growth and development.

The Rab GTPase in the heart: Pivotal roles in development and disease

Rab proteins are a family of small GTPases that function as molecular switches of intracellular vesicle formation and membrane trafficking. As a key factor, Rab GTPase participates in autophagy and protein transport and acts as the central hub of membrane trafficking in eukaryotes. The role of Rab GTPase in neurodegenerative disorders, such as Alzheimer's and Parkinson's, has been extensively investigated; however, its implication in cardiovascular embryogenesis and diseases remains largely unknown. In this review, we summarize previous findings and reveal their importance in the onset and progression of cardiac diseases, as well as their emergence as potential therapeutic targets for cardiovascular disease.

Reactive Oxygen Species Bridge the Gap between Chronic Inflammation and Tumor Development

According to numerous animal studies, adverse environmental stimuli, including physical, chemical, and biological factors, can cause low-grade chronic inflammation and subsequent tumor development. Human epidemiological evidence has confirmed the close relationship between chronic inflammation and tumorigenesis. However, the mechanisms driving the development of persistent inflammation toward tumorigenesis remain unclear. In this study, we assess the potential role of reactive oxygen species (ROS) and associated mechanisms in modulating inflammation-induced tumorigenesis. Recent reports have emphasized the cross-talk between oxidative stress and inflammation in many pathological processes. Exposure to carcinogenic environmental hazards may lead to oxidative damage, which further stimulates the infiltration of various types of inflammatory cells. In turn, increased cytokine and chemokine release from inflammatory cells promotes ROS production in chronic lesions, even in the absence of hazardous stimuli. Moreover, ROS not only cause DNA damage but also participate in cell proliferation, differentiation, and apoptosis by modulating several transcription factors and signaling pathways. We summarize how changes in the redox state can trigger the development of chronic inflammatory lesions into tumors. Generally, cancer cells require an appropriate inflammatory microenvironment to support their growth, spread, and metastasis, and ROS may provide the necessary catalyst for inflammation-driven cancer. In conclusion, ROS bridge the gap between chronic inflammation and tumor development; therefore, targeting ROS and inflammation represents a new avenue for the prevention and treatment of cancer.

PKC is an indispensable factor in promoting environmental toxin chromium-mediated transformation and drug resistance

Hexavalent chromium [Cr(VI)] pollution is a serious environmental problem, due to not only its toxicity but also carcinogenesis. Although studies reveal several features of Cr(VI)-induced carcinogenesis, the underlying mechanisms of how Cr(VI) orchestrates multiple mitogenic pathways to promote tumor initiation and progression remain not fully understood. Src/Ras and other growth-related pathways are shown to be key players in Cr(VI)-initiated tumor prone actions. The role of protein kinase C (PKC, an important signal transducer) in Cr(VI)-mediated carcinogenesis has not been thoroughly investigated. In this study, using human bronchial/lung epithelial cells and keratinocytes, we demonstrate that PKC activity is increased by transient or chronic Cr(VI) exposure, which plays no role in the activation of Src/Ras signaling and ROS upregulation by this metal toxin. PKC in chronic Cr(VI)-treated cells stabilizes Bcl-2 to mitigate doxorubicin (an anti-cancer drug)-mediated apoptosis. After the suppression of this kinase by GO6976 (a PKC inhibitor), the cells chronically exposed to Cr(VI) partially regain the sensitivity to doxorubicin. However, when co-suppressed PKC and Ras, the chronic Cr(VI)-treated cells become fully responsive to doxorubicin and are unable to be transformed. Taken together, our study provides a new insight into the mechanisms, in which PKC is an indispensable player and cooperates with other mitogenic pathways to achieve Cr(VI)-induced carcinogenesis as well as to establish drug resistance. The data also suggest that active PKC can serve as a potential biomarker for early detection of health damages by Cr(VI) and therapeutic target for developing new treatments for diseases caused by Cr(VI).

Lipid Metabolism Regulates Oxidative Stress and Ferroptosis in RAS-Driven Cancers: A Perspective on Cancer Progression and Therapy

HRAS, NRAS and KRAS, collectively referred to as oncogenic RAS, are the most frequently mutated driver proto-oncogenes in cancer. Oncogenic RAS aberrantly rewires metabolic pathways promoting the generation of intracellular reactive oxygen species (ROS). In particular, lipids have gained increasing attention serving critical biological roles as building blocks for cellular membranes, moieties for post-translational protein modifications, signaling molecules and substrates for ß-oxidation. However, thus far, the understanding of lipid metabolism in cancer has been hampered by the lack of sensitive analytical platforms able to identify and quantify such complex molecules and to assess their metabolic flux in vitro and, even more so, in primary tumors. Similarly, the role of ROS in RAS-driven cancer cells has remained elusive. On the one hand, ROS are beneficial to the development and progression of precancerous lesions, by upregulating survival and growth factor signaling, on the other, they promote accumulation of oxidative by-products that decrease the threshold of cancer cells to undergo ferroptosis. Here, we overview the recent advances in the study of the relation between RAS and lipid metabolism, in the context of different cancer types. In particular, we will focus our attention on how lipids and oxidative stress can either promote or sensitize to ferroptosis RAS driven cancers. Finally, we will explore whether this fine balance could be modulated for therapeutic gain.

The Promoting Effect of Traumatic Brain Injury on the Incidence and Progression of Glioma: A Review of Clinical and Experimental Research

The role of traumatic brain injury in the development of glioma is highly controversial since first presented. This is not unexpected because traumatic brain injuries are overwhelmingly more common than glioma. However, the causes of post-traumatic glioma have been long discussed and still warrant further research. In this review, we have presented an overview of previous cohort studies and case–control studies. We have summarized the roles of microglial cells, macrophages, astrocytes, and stem cells in post-traumatic glioma formation and development, and reviewed various carcinogenic factors involved during traumatic brain injury, especially those reported in experimental studies indicating a relationship with glioma progression. Besides, traumatic brain injury and glioma share several common pathways, including inflammation and oxidative stress; however, the exact mechanism underlying this co-occurrence is yet to be discovered. In this review, we have summarized current epidemiological studies, clinical reports, pathophysiological research, as well as investigations evaluating the probable causes of co-occurrence and treatment possibilities. More efforts should be directed toward elucidating the relationship between traumatic brain injury and glioma, which could likely lead to promising pharmacological interventions towards designing therapeutic strategies.

An effective method to generate controllable levels of ROS for the enhancement of HUVEC proliferation using a chlorin e6-immobilized PET film as a photo-functional biomaterial

Reactive oxygen species (ROS) are byproducts of cellular metabolism; they play a significant role as secondary messengers in cell signaling. In cells, high concentrations of ROS induce apoptosis, senescence, and contact inhibition, while low concentrations of ROS result in angiogenesis, proliferation, and cytoskeleton remodeling. Thus, controlling ROS generation is an important factor in cell biology. We designed a chlorin e6 (Ce6)-immobilized polyethylene terephthalate (PET) film (Ce6-PET) to produce extracellular ROS under red-light irradiation. The application of Ce6-PET films can regulate the generation of ROS by altering the intensity of light-emitting diode sources. We confirmed that the Ce6-PET film could effectively promote cell growth under irradiation at 500 μW/cm2 for 30 min in human umbilical vein endothelial cells. We also found that the Ce6-PET film is more efficient in generating ROS than a Ce6-incorporated polyurethane film under the same conditions. Ce6-PET fabrication shows promise for improving the localized delivery of extracellular ROS and regulating ROS formation through the optimization of irradiation intensity.

Aspirin eugenol ester ameliorates paraquat-induced oxidative damage through ROS/p38-MAPK-mediated mitochondrial apoptosis pathway

Paraquat (PQ) is an effective and commercially important herbicide that is widely used worldwide. However, PQ is highly toxic and can cause various complications and acute organ damage. Aspirin eugenol ester (AEE) is a potential new compound with anti-inflammatory and antioxidant stress pharmacological activity. The present study was to reveal the therapeutic effects and the protective effect of AEE against PQ-induced acute lung injury (ALI) with the help of PQ-induced oxidative damage in A549 cells and PQ-induced lung injury in rats. AEE might have no significant therapeutic effect on PQ-induced lung injury in rats. However, AEE had a significant protective effect on PQ-induced lung injury in rats. AEE pretreatment significantly reduced the stimulatory effect of PQ on malondialdehyde (MDA), the inhibitory effect of PQ on catalase (CAT) activity, superoxide dismutase (SOD) activity, glutathione peroxidase (GPx) activity, the ratio of GSH/GSSH, the activity of caspase-3 and the overexpression of p38 mitogen-activated protein kinase (MAPK) phosphorylation in vivo. In vitro, A549 cells were treated with 250 μM PQ for 24 h. Incubation of A549 cells with PQ led to apoptosis, and increased the level of superoxide anions, reactive oxygen species (ROS), malondialdehyde and the activity of caspase-3 and up-regulation of phosphorylated p38-MAPK, reduced mitochondrial membrane potential (ΔΨm) and the activity of SOD. However, after 24 h on AEE pretreatment of A549 cells, the above-mentioned adverse reactions caused by PQ were significantly alleviated. In addition, AEE pretreatment reduced p38-MAPK phosphorylation in PQ-treated A549 cells. SB203580, the specific p38-MAPK inhibitor, and p38-MAPK shRNA attenuated the activation of the p38-MAPK signaling pathway. N-acetylcysteine (NAC) reduced the level of phosphorylated p38-MAPK and the production of intracellular ROS and inhibited apoptosis. The results showed that AEE may inhibit PQ-induced cell damage through ROS/p38-MAPK-mediated mitochondrial apoptosis pathway.

Oleanolic acid ameliorates intestinal alterations associated with EAE

Background

Multiple sclerosis (MS) is a chronic demyelinating autoimmune disease affecting the CNS. Recent studies have indicated that intestinal alterations play key pathogenic roles in the development of autoimmune diseases, including MS. The triterpene oleanolic acid (OA), due to its anti-inflammatory properties, has shown to beneficially influence the severity of the experimental autoimmune encephalomyelitis (EAE), a preclinical model of MS. We herein investigate EAE-associated gut intestinal dysfunction and the effect of OA treatment.

Methods

Mice with MOG_35–55-induced EAE were treated with OA or vehicle from immunization day and were daily analyzed for clinical deficit. We performed molecular and histological analysis in serum and intestinal tissues to measure oxidative and inflammatory responses. We used Caco-2 and HT29-MTX-E12 cells to elucidate OA in vitro effects.

Results

We found that OA protected from EAE-induced changes in intestinal permeability and preserved the mucin-containing goblet cells along the intestinal tract.

Serum levels of the markers for intestinal barrier damage iFABP and monocyte activation sCD14 were consistently and significantly reduced in OA-treated EAE mice. Beneficial OA effects also included a decrease of pro-inflammatory mediators both in serum and colonic tissue of treated-EAE mice. Moreover, the levels of some immunoregulatory cytokines, the neurotrophic factor GDNF, and the gastrointestinal hormone motilin were preserved in OA-treated EAE mice. Regarding oxidative stress, OA treatment prevented lipid peroxidation and superoxide anion accumulation in intestinal tissue, while inducing the expression of the ROS scavenger Sestrin-3. Furthermore, short-chain fatty acids (SCFA) quantification in the cecal content showed that OA reduced the high iso-valeric acid concentrations detected in EAE-mice. Lastly, using in vitro cell models which mimic the intestinal epithelium, we verified that OA protected against intestinal barrier dysfunction induced by injurious agents produced in both EAE and MS.

Conclusion

These findings reveal that OA ameliorates the gut dysfunction found in EAE mice. OA normalizes the levels of gut mucosal dysfunction markers, as well as the pro- and anti-inflammatory immune bias during EAE, thus reinforcing the idea that OA is a beneficial compound for treating EAE and suggesting that OA may be an interesting candidate to be explored for the treatment of human MS.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12974-020-02042-6.

Metabolic Potential of Cancer Cells in Context of the Metastatic Cascade

The metastatic cascade is a highly plastic and dynamic process dominated by cellular heterogeneity and varying metabolic requirements. During this cascade, the three major metabolic pillars, namely biosynthesis, RedOx balance, and bioenergetics, have variable importance. Biosynthesis has superior significance during the proliferation-dominated steps of primary tumour growth and secondary macrometastasis formation and only minor relevance during the growth-independent processes of invasion and dissemination. Consequently, RedOx homeostasis and bioenergetics emerge as conceivable metabolic key determinants in cancer cells that disseminate from the primary tumour. Within this review, we summarise our current understanding on how cancer cells adjust their metabolism in the context of different microenvironments along the metastatic cascade. With the example of one-carbon metabolism, we establish a conceptual view on how the same metabolic pathway can be exploited in different ways depending on the current cellular needs during metastatic progression.

Ferroptosis: Final destination for cancer?

Ferroptosis is a recently defined, non‐apoptotic, regulated cell death (RCD) process that comprises abnormal metabolism of cellular lipid oxides catalysed by iron ions or iron‐containing enzymes. In this process, a variety of inducers destroy the cell redox balance and produce a large number of lipid peroxidation products, eventually triggering cell death. However, in terms of morphology, biochemistry and genetics, ferroptosis is quite different from apoptosis, necrosis, autophagy‐dependent cell death and other RCD processes. A growing number of studies suggest that the relationship between ferroptosis and cancer is extremely complicated and that ferroptosis promises to be a novel approach for the cancer treatment. This article primarily focuses on the mechanism of ferroptosis and discusses the potential application of ferroptosis in cancer therapy.

Heat shock proteins in the physiology and pathophysiology of epidermal keratinocytes

Heat shock proteins (HSPs), a large group of highly evolutionary conserved proteins, are considered to be main elements of the cellular proteoprotection system. HSPs are encoded by genes activated during the exposure of cells to proteotoxic factors, as well as by genes that are expressed constitutively under physiological conditions. HSPs, having properties of molecular chaperones, are involved in controlling/modulation of multiple cellular and physiological processes. In the presented review, we summarize the current knowledge on HSPs in the biology of epidermis, the outer skin layer composed of stratified squamous epithelium. This tissue has a vital barrier function preventing from dehydratation due to passive diffusion of water out of the skin, and protecting from infection and other environmental insults. We focused on HSPB1 (HSP27), HSPA1 (HSP70), HSPA2, and HSPC (HSP90), because only these HSPs have been studied in the context of physiology and pathophysiology of the epidermis. The analysis of literature data shows that HSPB1 plays a role in the regulation of final steps of keratinization; HSPA1 is involved in the cytoprotection, HSPA2 contributes to the early steps of keratinocyte differentiation, while HSPC is essential in the re-epithelialization process. Since HSPs have diverse functions in various types of somatic tissues, in spite of multiple investigations, open questions still remain about detailed roles of a particular HSP isoform in the biology of epidermal keratinocytes.

The interrelationship between cerebral ischemic stroke and glioma: a comprehensive study of recent reports

Glioma and cerebral ischemic stroke are two major events that lead to patient death worldwide. Although these conditions have different physiological incidences, ~10% of ischemic stroke patients develop cerebral cancer, especially glioma, in the postischemic stages. Additionally, the high proliferation, venous thrombosis and hypercoagulability of the glioma mass increase the significant risk of thromboembolism, including ischemic stroke. Surprisingly, these events share several common pathways, viz. hypoxia, cerebral inflammation, angiogenesis, etc., but the proper mechanism behind this co-occurrence has yet to be discovered. The hypercoagulability and presence of the D-dimer level in stroke are different in cancer patients than in the noncancerous population. Other factors such as atherosclerosis and coagulopathy involved in the pathogenesis of stroke are partially responsible for cancer, and the reverse is also partially true. Based on clinical and neurosurgical experience, the neuronal structures and functions in the brain and spine are observed to change after a progressive attack of ischemia that leads to hypoxia and atrophy. The major population of cancer cells cannot survive in an adverse ischemic environment that excludes cancer stem cells (CSCs). Cancer cells in stroke patients have already metastasized, but early-stage cancer patients also suffer stroke for multiple reasons. Therefore, stroke is an early manifestation of cancer. Stroke and cancer share many factors that result in an increased risk of stroke in cancer patients, and vice-versa. The intricate mechanisms for stroke with and without cancer are different. This review summarizes the current clinical reports, pathophysiology, probable causes of co-occurrence, prognoses, and treatment possibilities.

Thermal cycling effect on osteogenic differentiation of MC3T3-E1 cells loaded on 3D-porous Biphasic Calcium Phosphate (BCP) scaffolds for early osteogenesis

The application of heat stress on a defect site during the healing process is a promising technique for early bone regeneration. The primary goal of this study was to investigate the effect of periodic heat shock on bone formation. MC3T3-E1 cells were seeded onto biphasic calcium phosphate (BCP) scaffolds, followed by periodic heating to evaluate osteogenic differentiation. Heat was applied to cells seeded onto scaffolds at 41 °C for 1 h once, twice, and four times a day for seven days and their viability, morphology, and differentiation were analyzed. BCP scaffolds with interconnected porous structures mimic bone biology for cellular studies. MTT and confocal studies have shown that heat shock significantly increased cell proliferation without any toxic effects. Compared to non-heated samples, heat shock enhanced calcium deposition and mineralization, which could be visualized by SEM observation and Alizarin red S staining. Immunostaining images showed the localization of osteogenic proteins ALP and OPN on heat-shocked cells. qRT-PCR analysis revealed the presence of more osteospecific markers, osteopontin (OPN), osteocalcin, collagen type X, and Runx2, in the heat-shocked samples than in the non-heated sample. Periodic heat shock significantly upregulated both heat shock proteins (HSP70 and HSP27) in differentiated MC3T3-E1 cells. The results of this study demonstrated that periodically heat applied especially two times a day was better approach for osteogenic differentiation. Hence, this work provides a define temperature and time schedule for the development of a clinical heating device in future for early bone regeneration during the postsurgical period.

Cysteine-based regulation of redox-sensitive Ras small GTPases

Reactive oxygen and nitrogen species (ROS and RNS, respectively) activate the redox-sensitive Ras small GTPases. The three canonical genes (HRAS, NRAS, and KRAS) are archetypes of the superfamily of small GTPases and are the most common oncogenes in human cancer. Oncogenic Ras is intimately linked to redox biology, mainly in the context of tumorigenesis. The Ras protein structure is highly conserved, especially in effector-binding regions. Ras small GTPases are redox-sensitive proteins thanks to the presence of the NKCD motif (Asn116-Lys 117-Cys118-Asp119). Notably, the ROS- and RNS-based oxidation of Cys118 affects protein stability, activity, and localization, and protein-protein interactions. Cys residues at positions 80, 181, 184, and 186 may also help modulate these actions. Moreover, oncogenic mutations of Gly12Cys and Gly13Cys may introduce additional oxidative centres and represent actionable drug targets. Here, the pathophysiological involvement of Cys-redox regulation of Ras proteins is reviewed in the context of cancer and heart and brain diseases.

Investigating the Effects of Stove Emissions on Ocular and Cancer Cells

More than a third of the world’s population relies on solid fuels for cooking and heating, with major health consequences. Although solid fuel combustion emissions are known to increase the prevalence of illnesses such as chronic obstructive pulmonary disease and lung cancer, however, their effect on the eyes is underexplored. This study assesses the acute toxicity of solid fuel combustion emissions on healthy ocular cells and a cancer cell line. Three healthy ocular cell lines (corneal, lens, and retinal epithelial cells) and a cancer cell line (Chinese hamster ovary cells) were exposed to liquid and gas phase emissions from applewood and coal combustion. Following the exposure, real-time cell attachment behavior was monitored for at least 120 hours with electrical cell impedance spectroscopy. The viability of the cells, amount of apoptotic cells, and generation of reactive oxygen species (ROS) were quantified with MTT, ApoTox-Glo, and ROS-Glo H₂O₂ assays, respectively. The results showed that coal emissions compromised the viability of ocular cells more than applewood emissions. Interestingly, the cancer cells, although their viability was not compromised, generated 1.7 to 2.7 times more ROS than healthy cells. This acute exposure study provides compelling proof that biomass combustion emissions compromise the viability of ocular cells and increase ROS generation. The increased ROS generation was fatal for ocular cells, but it promoted the growth of cancer cells.

A dense mapping study of six European AITD susceptibility regions in a large Chinese Han Cohort of Graves' disease

OBJECTIVE

We aimed to investigate the six susceptibility loci of GD identified from European population in Chinese Han population and further to estimate the genetic heterogeneity of them in stratification of our GD patients.

DESIGN

Dense mapping studies based on GWAS.

PATIENTS

A total of 1536 GD patients and 1516 controls in GWAS stage and 1994 GD patients and 2085 controls and 5033 GD patients and 5389 controls in two replication stages.

MEASUREMENTS

Based on our previous GWAS data, independently GD-associated SNPs in each region were identified by TagSNP analysis and logistic regression analysis. The association of these SNPs was investigated in 1994 GD patients and 2085 controls, and then, the significantly associated SNPs (P < 0.05) were further genotyped in a second cohort including 5033 GD patients and 5389 controls.

RESULTS

After the first replication stage, four SNPs from three regions with P_first  < 0.05 were further selected and genotyped in another independent cohort. The association of two SNPs with GD was confirmed in combined Chinese cohorts: rs12575636 at 11q21 (P_combined  = 7.55 × 10^-11 , OR = 1.27) and rs1881145 in TRIB2 at 2p25.1 (P_combined  = 5.59 × 10^-8 , OR = 1.14). Further study disclosed no significant difference for these SNPs between GD subsets. However, eQTL data revealed that SESN3 could be a potential susceptibility gene of GD in 11q21 region.

CONCLUSIONS

Out of the six susceptibility loci of GD identified from European population, two risk loci were confirmed in a large Chinese Han population. There is variability in GD genetic susceptibility in different ethnic groups. SESN3 is a potential susceptible gene of GD in 11q21.

Increased Reactive Oxygen Species and Cell Cycle Defects Contribute to Anemia in the RASA3 Mutant Mouse Model scat

RASA3 is a Ras GTPase activating protein that plays a critical role in blood formation. The autosomal recessive mouse model scat (severe combined anemia and thrombocytopenia) carries a missense mutation in Rasa3. Homozygotes present with a phenotype characteristic of bone marrow failure that is accompanied by alternating episodes of crisis and remission. The mechanism leading to impaired erythropoiesis and peripheral cell destruction as evidenced by membrane fragmentation in scat is unclear, although we previously reported that the mislocalization of RASA3 to the cytosol of reticulocytes and mature red cells plays a role in the disease. In this study, we further characterized the bone marrow failure in scat and found that RASA3 plays a central role in cell cycle progression and maintenance of reactive oxygen species (ROS) levels during terminal erythroid differentiation, without inducing apoptosis of the precursors. In scat mice undergoing crises, there is a consistent pattern of an increased proportion of cells in the G₀/G₁ phase at the basophilic and polychromatophilic stages of erythroid differentiation, suggesting that RASA3 is involved in the G₁ checkpoint. However, this increase in G₁ is transient, and either resolves or becomes indiscernible by the orthochromatic stage. In addition, while ROS levels are normal early in erythropoiesis, there is accumulation of superoxide levels at the reticulocyte stage (DHE increased 40% in scat; p = 0.02) even though mitochondria, a potential source for ROS, are eliminated normally. Surprisingly, apoptosis is significantly decreased in the scat bone marrow at the proerythroblastic (15.3%; p = 0.004), polychromatophilic (8.5%; p = 0.01), and orthochromatic (4.2%; p = 0.02) stages. Together, these data indicate that ROS accumulation at the reticulocyte stage, without apoptosis, contributes to the membrane fragmentation observed in scat. Finally, the cell cycle defect and increased levels of ROS suggest that scat is a model of bone marrow failure with characteristics of aplastic anemia.

How the Warburg effect supports aggressiveness and drug resistance of cancer cells?

Cancer cells employ both conventional oxidative metabolism and glycolytic anaerobic metabolism. However, their proliferation is marked by a shift towards increasing glycolytic metabolism even in the presence of O₂ (Warburg effect). HIF1, a major hypoxia induced transcription factor, promotes a dissociation between glycolysis and the tricarboxylic acid cycle, a process limiting the efficient production of ATP and citrate which otherwise would arrest glycolysis. The Warburg effect also favors an intracellular alkaline pH which is a driving force in many aspects of cancer cell proliferation (enhancement of glycolysis and cell cycle progression) and of cancer aggressiveness (resistance to various processes including hypoxia, apoptosis, cytotoxic drugs and immune response). This metabolism leads to epigenetic and genetic alterations with the occurrence of multiple new cell phenotypes which enhance cancer cell growth and aggressiveness. In depth understanding of these metabolic changes in cancer cells may lead to the development of novel therapeutic strategies, which when combined with existing cancer treatments, might improve their effectiveness and/or overcome chemoresistance.

MiR-16-5p targets SESN1 to regulate the p53 signaling pathway, affecting myoblast proliferation and apoptosis, and is involved in myoblast differentiation

The proliferation, apoptosis, and differentiation of myoblasts are essential processes in skeletal muscle development. During this developmental process, microRNAs (miRNAs) play crucial roles. In our previous RNA-seq study (accession number GSE62971), we found that miR-16-5p was differentially expressed between fast and slow growth in chicken. In this study, we report that miR-16-5p could inhibit myoblast proliferation, promote myoblast apoptosis, and repress myoblast differentiation by directly binding to the 3′ UTR of SESN1, which is also differentially expressed. Overexpression of SESN1 significantly promoted the proliferation, inhibited apoptosis, and induced differentiation of myoblasts. Conversely, its loss of function hampered myoblast proliferation, facilitated myoblast apoptosis, and inhibited myoblast differentiation. Interestingly, we found SESN1 could regulate p53 by a feedback mechanism, thereby participating in the regulation of p53 signaling pathway, which suggests that this feedback is indispensable for myoblast proliferation and apoptosis. Altogether, these data demonstrated that miR-16-5p directly targets SESN1 to regulate the p53 signaling pathway, and therefore affecting myoblast proliferation and apoptosis. Additionally, SESN1 targets myogenic genes to control myoblast differentiation.

Peroxiredoxin I is important for cancer-cell survival in Ras-induced hepatic tumorigenesis

Peroxiredoxin I (Prx I), an antioxidant enzyme, has multiple functions in human cancer. However, the role of Prx I in hepatic tumorigenesis has not been characterized. Here we investigated the relevance and underlying mechanism of Prx I in hepatic tumorigenesis. Prx I increased in tumors of hepatocellular carcinoma (HCC) patients that aligned with overexpression of oncogenic H-ras. Prx I also increased in H-ras^G12V transfected HCC cells and liver tumors of H-ras^G12V transgenic (Tg) mice, indicating that Prx I may be involved in Ras-induced hepatic tumorigenesis. When Prx I was knocked down or deleted in HCC-H-ras^G12V cells or H-ras^G12V Tg mice, cell colony or tumor formation was significantly reduced that was associated with downregulation of pERK pathway as well as increased intracellular reactive oxygen species (ROS) induced DNA damage and cell death. Overexpressing Prx I markedly increased Ras downstream pERK/FoxM1/Nrf2 signaling pathway and inhibited oxidative damage in HCC cells and H-ras^G12V Tg mice. In this study, we found Nrf2 was transcriptionally activated by FoxM1, and Prx I was activated by the H-ras^G12V/pERK/FoxM1/Nrf2 pathway and suppressed ROS-induced hepatic cancer-cell death along with formation of a positive feedback loop with Ras/ERK/FoxM1/Nrf2 to promote hepatic tumorigenesis.

E-Cadherin repression increases amount of cancer stem cells in human A549 lung adenocarcinoma and stimulates tumor growth

Here we show that cancer stem cells amount in human lung adenocarcinoma cell line A549 depends on E-cadherin expression. In fact, downregulation of E-cadherin expression enhanced expression of pluripotent genes (c-MYC, NESTIN, OCT3/4 and SOX2) and enriched cell population with the cells possessing the properties of so-called 'cancer stem cells' via activation of Wnt/β-catenin signaling. Repression of E-cadherin also stimulated cell proliferation and migration in vitro, decreased cell amount essential for xenografts formation in nude mice, increased tumors vascularization and growth. On the other hand, E-cadherin upregulation caused opposite effects i.e. diminished the number of cancer stem cells, decreased xenograft vascularization and decelerated tumor growth. Therefore, agents restoring E-cadherin expression may be useful in anticancer therapy.

KRas, ROS and the initiation of pancreatic cancer

Oncogenic mutations of KRAS are the most frequent driver mutations in pancreatic cancer. Expression of an oncogenic allele of KRAS leads to metabolic changes and altered cellular signaling that both can increase the production of intracellular reactive oxygen species (ROS). Increases in ROS have been shown to drive the formation and progression of pancreatic precancerous lesions by upregulating survival and growth factor signaling. A key issue for precancerous and cancer cells is to keep ROS at levels where they are beneficial for tumor development and progression, but below the threshold that leads to induction of senescence or cell death. In KRas-driven neoplasia aberrantly increased ROS levels are therefore balanced by an upregulation of antioxidant genes.

Tumor promotion by γ and suppression by β non-muscle actin isoforms

Here we have shown that β-cytoplasmic actin acts as a tumor suppressor, inhibiting cell growth and invasion in vitro and tumor growth in vivo. In contrast, γ-cytoplasmic actin increases the oncogenic potential via ERK1/2, p34-Arc, WAVE2, cofilin1, PP1 and other regulatory proteins. There is a positive feedback loop between γ-actin expression and ERK1/2 activation. We conclude that non-muscle actin isoforms should not be considered as merely housekeeping proteins and the β/γ-actins ratio can be used as an oncogenic marker at least for lung and colon carcinomas. Agents that increase β- and/or decrease γ-actin expression may be useful for anticancer therapy.

Let-7a regulates mammosphere formation capacity through Ras/NF-κB and Ras/MAPK/ERK pathway in breast cancer stem cells

Breast cancer stem cells (BCSCs) have the greatest potential to maintain tumorigenesis in all subtypes of tumor cells and were regarded as the key drivers of tumor. Recent evidence has demonstrated that BCSCs contributed to a high degree of resistance to therapy. However, how BCSCs self renewal and tumorigenicity are maintained remains obscure. Herein, our study illustrated that overexpression of let-7a reduced cell proliferation and mammosphere formation ability of breast cancer stem cells(BCSCs) in a KRas-dependent manner through different pathways in vitro and in vivo. To be specific, we provided the evidence that let-7a was decreased, and reversely the expression of KRas was increased with moderate expression in early stages (I/II) and high expression in advanced stages (III/IV) in breast cancer specimens. In addition, the negative correlation between let-7a and KRas was clearly observed. In vitro, we found that let-7a inhibited mammosphere-forming efficiency and the mammosphere-size via NF-κB and MAPK/ERK pathway, respectively. The inhibitory effect of let-7a on mammosphere formation efficiency and the size of mammospheres was abolished after the depletion of KRas. On the contrary, enforced expression of KRas rescued the effect of let-7a. In vivo, let-7a inhibited the growth of tumors, whereas the negative effect of let-7a was rescued after overexpressing KRas. Taken together, our findings suggested that let-7a played a tumor suppressive role in a KRas-dependent manner.

Peroxiredoxin II Is Essential for Maintaining Stemness by Redox Regulation in Liver Cancer Cells

Redox regulation in cancer stem cells (CSCs) is viewed as a good target for cancer therapy because redox status plays an important role in cancer stem-cell maintenance. Here, we investigated the role of Peroxiredoxin II (Prx II), an antioxidant enzyme, in association with maintenance of liver CSCs. Our study demonstrates that Prx II overexpressed in liver cancer cells has high potential for self-renewal activity. Prx II expression significantly corelated with expression of epithelial-cell adhesion molecules (EpCAM) and cytokerain 19 in liver cancer tissues of hepatocellular carcinoma (HCC) patients. Downregulation of Prx II in Huh7 cells with treatment of siRNA reduced expression of EpCAM and CD133 as well as Sox2 in accordance with increased ROS and apoptosis, which were reversed in Huh7-hPrx II cells. Huh7-hPrx II cells exhibited strong sphere-formation activity compared with mock cells. Vascular endothelial growth factor (VEGF) exposure enhanced sphere formation, cell-surface expression of EpCAM and CD133, and pSTAT3 along with activation of VEGF receptor 2 in Huh7-hPrx II cells. The result also emerged in Huh7-H-ras(G12V) and SK-HEP-1-H-ras(G12V) cells with high-level expression of Prx II. Prx II was involved in regulation of VEGF driving cancer stem cells through VEGFR-2/STAT3 signaling to upregulate Bmi1 and Sox2. In addition, knockdown of Prx II in Huh7-H-ras(G12V) cells showed significant reduction in cell migration in vitro and in tumorigenic potential in vivo. Taken together, all the results demonstrated that Prx II plays a key role in the CSC self-renewal of HCC cells through redox regulation. Stem Cells 2016;34:1188-1197.

Cryptotanshinone inhibits proliferation and induces apoptosis via mitochondria-derived reactive oxygen species involving FOXO1 in estrogen receptor-negative breast cancer Bcap37 cells

Cryptotanshinone inhibits proliferation and induces apoptosis of the estrogen receptor-negative breast cancer Bcap37 cells via FOXO1 inhibition and ROS-mediated PI3K/AKT/mTOR signaling pathways.

Inactivation of Sag/Rbx2/Roc2 e3 ubiquitin ligase triggers senescence and inhibits kras-induced immortalization

Our recent study showed that SAG/RBX2 E3 ubiquitin ligase regulates apoptosis and vasculogenesis by promoting degradation of NOXA and NF1, and co-operates with Kras to promote lung tumorigenesis by activating NFκB and mTOR pathways via targeted degradation of tumor suppressive substrates including IκB, DEPTOR, p21 and p27. Here we investigated the role of Sag/Rbx2 E3 ligase in cellular senescence and immortalization of mouse embryonic fibroblasts (MEFs) and report that Sag is required for proper cell proliferation and Kras^G12D-induced immortalization. Sag inactivation by genetic deletion remarkably suppresses cell proliferation by inducing senescence, which is associated with accumulation of p16, but not p53. Mechanistically, Sag deletion caused accumulation of Jun-B, a substrate of Sag-Fbxw7 E3 ligase and a transcription factor that drives p16 transcription. Importantly, senescence triggered by Sag deletion can be largely rescued by simultaneous deletion of Cdkn2a, the p16 encoding gene, indicating its causal role. Furthermore, Kras^G12D-induced immortalization can also be abrogated by Sag deletion via senescence induction, which is again rescued by simultaneous deletion of Cdkn2a. Finally, we found that Sag deletion inactivates Kras^G12D activity and block the MAPK signaling pathway, together with accumulated p16, to induce senescence. Taken together, our results demonstrated that Sag is a Kras^G12D-cooperating oncogene required for Kras^G12D-induced immortalization and transformation, and targeting SAG-SCF E3 ligase may, therefore, have therapeutic value for senescence-based cancer treatment.

Erbin is a novel substrate of the Sag-βTrCP E3 ligase that regulates KrasG12D-induced skin tumorigenesis

In contrast to previous results in the lung, skin-specific deletion of the Sag-βTrCP E3 ubiquitin ligase significantly accelerates mutant Kras^G12D-induced skin papillomagenesis due to accumulation of Erbin and Nrf2, two novel Sag substrates, which blocks ROS generation and promotes proliferation.

SAG/RBX2 is the RING (really interesting new gene) component of Cullin-RING ligase, which is required for its activity. An organ-specific role of SAG in tumorigenesis is unknown. We recently showed that Sag/Rbx2, upon lung-targeted deletion, suppressed Kras^G12D-induced tumorigenesis via inactivating NF-κB and mammalian target of rapamycin pathways. In contrast, we report here that, upon skin-targeted deletion, Sag significantly accelerated Kras^G12D-induced papillomagenesis. In Kras^G12D-expressing primary keratinocytes, Sag deletion promotes proliferation by inhibiting autophagy and senescence, by inactivating the Ras–Erk pathway, and by blocking reactive oxygen species (ROS) generation. This is achieved by accumulation of Erbin to block Ras activation of Raf and Nrf2 to scavenge ROS and can be rescued by knockdown of Nrf2 or Erbin. Simultaneous one-allele deletion of the Erbin-encoding gene Erbb2ip partially rescued the phenotypes. Finally, we characterized Erbin as a novel substrate of SAG-βTrCP E3 ligase. By degrading Erbin and Nrf2, Sag activates the Ras–Raf pathway and causes ROS accumulation to trigger autophagy and senescence, eventually delaying Kras^G12D-induced papillomagenesis and thus acting as a skin-specific tumor suppressor.

Control of Trx1 redox state modulates protection against methyl methanesulfonate-induced DNA damage via stabilization of p21

Thioredoxin 1 (Trx1) is known to play an important role in protecting against cell death. However, the mechanism for control of Trx1 in cell death resulting from DNA damage has not been fully investigated. In this study, we used the DNA-damaging agent methyl methanesulfonate (MMS) to investigate the protective effects of Trx1 against DNA damage and cell death in HEK293 cells. We found that MMS application caused dose-dependent changes in the Trx1 redox state determined by redox western blotting. At lower concentrations, both reduced and oxidized Trx1 were observed, whereas the reduced band was fully oxidized at the higher concentration. Trx1 overexpression and small interfering RNA knockdown in cells revealed that reduced Trx1 after exposure to lower doses of MMS attenuated DNA damage, assessed by comet assay, and level of the DNA-damage marker histone γ-H2AX, possibly through scavenging intracellular ROS and an increase in p21 protein level via enhancing its stability. However, oxidized Trx1 lost its protective ability to DNA damage in response to higher concentration of MMS. Corresponding to the redox state control of Trx1, cell death induced by different dose of MMS was also found, by inhibiting phosphorylations of p38 and 4E-BP1. These results indicate that reduced Trx1 plays important protective roles against MMS-induced DNA damage and cell death, suggesting that cell protection is regulated by the intracellular redox state. Control of the redox state of Trx1 and its regulating proteins may offer a novel therapeutic strategy for the control of cancer.

Novel robust biomarkers for human bladder cancer based on activation of intracellular signaling pathways

We recently proposed a new bioinformatic algorithm called OncoFinder for quantifying the activation of intracellular signaling pathways. It was proved advantageous for minimizing errors of high-throughput gene expression analyses and showed strong potential for identifying new biomarkers. Here, for the first time, we applied OncoFinder for normal and cancerous tissues of the human bladder to identify biomarkers of bladder cancer. Using Illumina HT12v4 microarrays, we profiled gene expression in 17 cancer and seven non-cancerous bladder tissue samples. These experiments were done in two independent laboratories located in Russia and Canada. We calculated pathway activation strength values for the investigated transcriptomes and identified signaling pathways that were regulated differently in bladder cancer (BC) tissues compared with normal controls. We found, for both experimental datasets, 44 signaling pathways that serve as excellent new biomarkers of BC, supported by high area under the curve (AUC) values. We conclude that the OncoFinder approach is highly efficient in finding new biomarkers for cancer. These markers are mathematical functions involving multiple gene products, which distinguishes them from “traditional” expression biomarkers that only assess concentrations of single genes.

Pathway activation profiling reveals new insights into age-related macular degeneration and provides avenues for therapeutic interventions

Age-related macular degeneration (AMD) is a major cause of blindness in older people and is caused by loss of the central region of the retinal pigment epithelium (RPE). Conventional methods of gene expression analysis have yielded important insights into AMD pathogenesis, but the precise molecular pathway alterations are still poorly understood. Therefore we developed a new software program, “AMD Medicine”, and discovered differential pathway activation profiles in samples of human RPE/choroid from AMD patients and controls. We identified 29 pathways in RPE-choroid AMD phenotypes: 27 pathways were activated in AMD compared to controls, and 2 pathways were activated in controls compared to AMD. In AMD, we identified a graded activation of pathways related to wound response, complement cascade, and cell survival. Also, there was downregulation of two pathways responsible for apoptosis. Furthermore, significant activation of pro-mitotic pathways is consistent with dedifferentiation and cell proliferation events, which occur early in the pathogenesis of AMD. Significantly, we discovered new global pathway activation signatures of AMD involved in the cell-based inflammatory response: IL-2, STAT3, and ERK. The ultimate aim of our research is to achieve a better understanding of signaling pathways involved in AMD pathology, which will eventually lead to better treatments.

Systems genetics identifies Sestrin 3 as a regulator of a proconvulsant gene network in human epileptic hippocampus

Gene-regulatory network analysis is a powerful approach to elucidate the molecular processes and pathways underlying complex disease. Here we employ systems genetics approaches to characterize the genetic regulation of pathophysiological pathways in human temporal lobe epilepsy (TLE). Using surgically acquired hippocampi from 129 TLE patients, we identify a gene-regulatory network genetically associated with epilepsy that contains a specialized, highly expressed transcriptional module encoding proconvulsive cytokines and Toll-like receptor signalling genes. RNA sequencing analysis in a mouse model of TLE using 100 epileptic and 100 control hippocampi shows the proconvulsive module is preserved across-species, specific to the epileptic hippocampus and upregulated in chronic epilepsy. In the TLE patients, we map the trans-acting genetic control of this proconvulsive module to Sestrin 3 (SESN3), and demonstrate that SESN3 positively regulates the module in macrophages, microglia and neurons. Morpholino-mediated Sesn3 knockdown in zebrafish confirms the regulation of the transcriptional module, and attenuates chemically induced behavioural seizures in vivo.

Sestrins orchestrate cellular metabolism to attenuate aging

The Sestrins constitute a family of evolutionarily conserved stress-inducible proteins that suppress oxidative stress and regulate AMP-dependent protein kinase (AMPK)-mammalian target of rapamycin (mTOR) signaling. By virtue of these activities, the Sestrins serve as important regulators of metabolic homeostasis. Accordingly, inactivation of Sestrin genes in invertebrates resulted in diverse metabolic pathologies, including oxidative damage, fat accumulation, mitochondrial dysfunction, and muscle degeneration, that resemble accelerated tissue aging. Likewise, Sestrin deficiencies in mice led to accelerated diabetic progression upon obesity. Further investigation of Sestrin function and regulation should provide new insights into age-associated metabolic diseases, such as diabetes, myopathies, and cancer.

CIZ1 regulates the proliferation, cycle distribution and colony formation of RKO human colorectal cancer cells

Cip1-interacting zinc finger protein 1 (CIZ1) is a nuclear protein that was observed to bind to p21Cip1/Waf1. p21Cip1/Waf1 regulates the cell cycle and is associated with colorectal cancer (CRC) progression. However, the effect of CIZ1 on CRC cells remains unclear. In the present study, CIZ1 was observed to be highly expressed in RKO human CRC cells. Silencing of CIZ1 using small interfering RNA (siRNA) suppressed RKO cell proliferation. Flow cytometric analysis demonstrated that knockdown of CIZ1 decreased the percentage of cells in the S phase and increased the ratio of cells in the G0/G1 phase in parallel with upregulated cell apoptosis. Moreover, the number and size of RKO cell colonies was repressed by knockdown of the CIZ1 gene. These results suggested that CIZ1 may be involved in colon cancer progression by regulating cell proliferation, cell cycle, apoptosis and colony formation. Furthermore, CIZ1‑siRNA may provide a novel tool for CRC investigation and therapy.

Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) signaling regulates mitochondrial biogenesis and respiration via estrogen-related receptor α (ERRα)

Mitochondrial abnormalities are associated with cancer development, yet how oncogenic signals affect mitochondrial functions has not been fully understood. In this study, we investigate the relationship between mitochondrial alterations and PI3K/protein kinase B (AKT) signaling activation using hepatocytes and liver tissues as our experimental models. We show here that liver-specific deletion of Pten, which leads to activation of PI3K/AKT, is associated with elevated oxidative stress, increased mitochondrial mass, and augmented respiration accompanied by enhanced glycolysis. Consistent with these observations, estrogen-related receptor α (ERRα), an orphan nuclear receptor known for its role in mitochondrial biogenesis, is up-regulated in the absence of phosphatase and tensin homolog deleted on chromosome 10 (PTEN). Our pharmacological and genetic studies show that PI3K/AKT activity regulates the expression of ERRα and mitochondrial biogenesis/respiration. Furthermore, cAMP-response element-binding protein, as a downstream target of AKT, plays a role in the regulation of ERRα, independent of PKA signaling. ERRα regulates reactive oxygen species production, and ERRα knockdown attenuates proliferation and colony-forming potential in Pten-null hepatocytes. Finally, analysis of clinical datasets from liver tissues showed a negative correlation between expressions of ERRα and PTEN in patients with liver cancer. Therefore, this study has established a previously unrecognized link between a growth signal and mitochondrial metabolism.