Fibroblast Growth Factor 6

Fibroblast Growth Factor 6 (FGF6), also referred to as HST2 or HBGF6, is a member of the Fibroblast Growth Factor (FGF), the Heparin Binding Growth Factor (HBGF) and the Heparin Binding Secretory Transforming Gene (HST) families. The genomic and protein structure of FGF6 is highly conserved among varied species, as is its expression in muscle and muscle progenitor cells. Like other members of the FGF family, FGF6 regulates cell proliferation, differentiation, and migration. Specifically, it plays key roles in myogenesis and muscular regeneration, angiogenesis, along with iron transport and lipid metabolism. Similar to others from the FGF family, FGF6 also possesses oncogenic transforming activity, and as such is implicated in a variety of cancers.

Dynamic changes of DNA methylation induced by benzo(a)pyrene in cancer

Benzo(a)pyrene (BaP), the earliest and most significant carcinogen among polycyclic aromatic hydrocarbons (PAHs), has been found in foods, tobacco smoke, and automobiles exhaust, etc. Exposure to BaP induced DNA damage directly, or oxidative stress-related damage, resulting in cell apoptosis and carcinogenesis in human respiratory system, digestive system, reproductive system, etc. Moreover, BaP triggered genome-wide epigenetic alterations by methylation, which might cause disturbances in regulation of gene expression, and thereby induced cancer. It has been proved that BaP reduced genome-wide DNA methylation, and activated proto-oncogene by hypomethylation in the promoter region, but silenced tumor suppressor genes by promoter hypermethylation, resulting in cancer initiation and progression. Here we summarized the changes in DNA methylation in BaP exposure, and revealed the methylation of DNA plays a role in cancer development.

Targeting Pokemon is a novel strategy to suppress cancer aggressiveness of non-small cell lung cancer: Identification of Pokemon as ideal target for developing anti-NSCLC drugs

Although it is widely reported that Pokemon acts as an oncogene in the pathogenesis of multiple cancers, but its role and detailed molecular mechanisms in regulating non-small cell lung cancer (NSCLC) progression have not been fully delineated. Here, by performing Real-Time qPCR analysis, we verified that Pokemon was high-expressed in NSCLC tissues and cells, compared to the corresponding normal lung tissues and epithelial cells. Then, the small interfering RNA (siRNA) for Pokemon was transfected into the NSCLC cells to verify its biological functions, and our results suggested that silencing of Pokemon suppressed the malignant phenotypes, including cell viability, mitosis, colony formation, epithelial-mesenchymal transition (EMT), mobility and cancer stem cell (CSC) properties in NSCLC cells. Mechanistically, we confirmed that knockdown of Pokemon decreased the expression levels of phosphorylated Akt (p-Akt), phosphorylated GSK-3β (p-GSK-3β) and Snail to inactivate the oncogenic Akt/GSK-3β/Snail signal pathway, and deletion of Snail also had similar effects to hamper the development of NSCLC. Next, our rescuing experiments validated that Pokemon ablation-induced suppressing effects on NSCLC cell malignancy were all abrogated by overexpressing Snail. Finally, the in vivo experiments confirmed that silencing of Pokemon downregulated Snail to hamper tumorigenesis of NSCLC cells in xenograft tumor-bearing mice models. Taken together, we firstly uncovered the underlying mechanisms by which the Pokemon/Akt/GSK-3β/Snail signal pathway contributed to the development of NSCLC, and this signal pathway could be potentially used as therapeutic targets for the development of personalized anti-NSCLC drugs.

Malathion alters the transcription of target genes of the tumour suppressor tp53 and cancerous processes in Colossoma macropomum: Mechanisms of DNA damage response, oxidative stress and apoptosis

Different classes of pesticides such as fungicides, herbicides, and insecticides, can induce differential expression of genes that are involved in tumorigenesis events in fish, including the expression of tumor suppressor tp53. The degree and duration of the stressful condition is decisive in defining which tp53-dependent pathway will be activated. Herein we evaluate the target genes expression that participates in the regulation pathway of the tumor suppressor tp53 and in the cancerous processes in tambaqui after exposure to malathion. Our hypothesis is that malathion promotes a gene response that is differentially regulated over time, with positive regulation of tp53 target genes related to the apoptotic pathway and a negative regulation of genes that promote antioxidant responses. The fish were exposed to a sublethal concentration of the insecticide for 6 and 48 h. Liver samples were used to analyze the expression of 11 genes using real-time PCR. Overall, the malathion promoted over time increases in tp53 expression and differential expression of tp53 related genes. The exposure resulted in the activation of damage response related genes, caused a positive expression of atm/atr genes. The pro-apoptotic gene bax was up-regulated and the anti-apoptotic bcl2 was down-regulated. Increased expression of mdm2 and sesn1 in the first hours of exposure and no effect on the antioxidant genes sod2 and gpx1 were also observed. We also witnessed an increase in the expression of the hif-1α gene, with no effect on ras proto-oncogene. The extension of this stressful condition accentuated tp53 transcription, and minimized the levels of mdm2, sens1 and bax; however, it down regulated the levels of bcl2 and the bcl2/bax ratio, which indicates the maintenance of the apoptotic response to the detriment of an antioxidant response.

MiR-211 plays a dual role in cancer development: From tumor suppressor to tumor enhancer

Cancer is a general term for more than 100 unique malignancies in different organs of the body. Each cancer type and subtype has its own unique genetic, epigenetic, and cellular factors accountable for malignant progression and metastasis. Small non-coding RNAs called miRNAs target mRNAs and play a vital part in the pathogenesis of human diseases, specifically cancer. Recent investigations provided knowledge of the deregulation of miR-211 in various cancer types and disclosed that miR-211 has an oncogenic or tumor-suppressive impact on tumourigenesis and cancer development. Moreover, recent discoveries which clarify the essential functions of miR-211 might provide proof for its prognosis, diagnostic and therapeutic impact on cancer. Thereby, this review will discuss recent findings regarding miR-211 expression level, target genes, and mechanisms in different cancers. In addition, the most recent results that propose miR-211 usefulness as a noninvasive biomarker and therapeutic factor for the diagnosis and treatment of cancer will be explained.

1HN, 13C, and 15N backbone resonance assignments of the SET/TAF-1β/I2PP2A oncoprotein (residues 23-225)

SET (TAF-1β/I2PP2A) is a ubiquitously expressed, multifunctional protein that plays a role in regulating diverse cellular processes, including cell cycle progression, migration, apoptosis, transcription, and DNA repair. SET expression is ubiquitous across all cell types. However, it is overexpressed or post-translationally modified in several solid tumors and blood cancers, where expression levels are correlated with worsening clinical outcomes. SET exerts its oncogenic effects primarily through the formation of antagonistic protein complexes with the tumor suppressor, protein phosphatase 2A (PP2A), and the well-known metastasis suppressor, nm23-H1. PP2A inhibition is often observed as a secondary driver of tumorigenesis and metastasis in human cancers. Preclinical studies have shown that the pharmacological reactivation of PP2A combined with potent inhibitors of the primary driver oncogene produces synergistic cell death and decreased drug resistance. Therefore, the development of novel inhibitors of the SET-PP2A interaction presents an attractive approach to reactivation of PP2A, and thereby, tumor suppression. NMR provides a unique platform to investigate protein targets in their natively folded state to identify protein and small-molecule ligands and report on the protein internal dynamics. The backbone ¹H^N, ¹³C, and ¹⁵N NMR resonance assignments were completed for the 204 amino acid nucleosome assembly protein-1 (NAP-1) domain of the human SET oncoprotein (residues 23-225). These assignments provide a vital first step toward the development of novel PP2A reactivators via SET-selective inhibition.

Two decades of a protooncogene HPIP/PBXIP1: Uncovering the tale from germ cell to cancer

Hematopoietic PBX interacting protein (HPIP or pre-B-cell leukemia transcription factor interacting protein (PBXIP1) was discovered two decades ago as a corepressor of pre-B-cell leukemia homeobox (PBX) 1 with a vital functional role in hematopoiesis. Later it emerged as a potential biomarker of poor prognosis and tumorigenesis for more than a dozen different cancers. It regulates aggressive cancer phenotypes, cell proliferation, metastasis, EMT, etc. The anomaly in the regulation of HPIP is linked with physiological disorders like renal fibrosis, chronic kidney disease and osteoarthritis. Scientists have unraveled more than twenty interacting proteins of HPIP and its functional role in various physiological and cellular processes that involves normal neuronal development, embryogenesis, endometrium decidualization, and germ cell proliferation. Over the past 20 years, we have witnessed the emerging role of HPIP and its association with a myriad of cellular activities ranging from germ cell proliferation to cancer aggressiveness, modulating multitude of signaling cascades like TGF-β1, PI3K/AKT, Wnt, mTOR, and Sonic hedgehog signaling pathways. This review will give the current understanding of HPIP, in terms of its diverse functions, theoretical ideas, and further explore cellular links and promising areas that need to be investigated. We also provide a comprehensive overview of the transcript variants of HPIP and distinct sets of transcription factors regulating their expression, which may help to understand the role of HPIP in various cellular or physiological conditions.

Targetable BRAF and RAF1 Alterations in Advanced Pediatric Cancers

RAF family protein kinases signal through the MAPK pathway to orchestrate cellular proliferation, survival, and transformation. Identifying BRAF alterations in pediatric cancers is critically important as therapeutic agents targeting BRAF or MEK may be incorporated into the clinical management of these patients. In this study, we performed comprehensive genomic profiling on 3,633 pediatric cancer samples and identified a cohort of 221 (6.1%) cases with known or novel alterations in BRAF or RAF1 detected in extracranial solid tumors, brain tumors, or hematological malignancies. Eighty percent (176/221) of these tumors had a known-activating short variant (98, 55.7%), fusion (72, 40.9%), or insertion/deletion (6, 3.4%). Among BRAF altered cancers, the most common tumor types were brain tumors (74.4%), solid tumors (10.8%), hematological malignancies (9.1%), sarcomas (3.4%), and extracranial embryonal tumors (2.3%). RAF1 fusions containing intact RAF1 kinase domain (encoded by exons 10-17) were identified in seven tumors, including two novel fusions TMF1-RAF1 and SOX6-RAF1. Additionally, we highlight a subset of patients with brain tumor with positive clinical response to BRAF inhibitors, demonstrating the rationale for incorporating precision medicine into pediatric oncology. IMPLICATIONS FOR PRACTICE: Precision medicine has not yet gained a strong foothold in pediatric cancers. This study describes the landscape of BRAF and RAF1 genomic alterations across a diverse spectrum of pediatric cancers, primarily brain tumors, but also encompassing melanoma, sarcoma, several types of hematologic malignancy, and others. Given the availability of multiple U.S. Food and Drug Administration-approved BRAF inhibitors, identification of these alterations may assist with treatment decision making, as described here in three cases of pediatric cancer.

Effect of photodynamic therapy on expression of HRAS, NRAS and caspase 3 genes at mRNA levels, apoptosis of head and neck squamous cell carcinoma cell line

OBJECTIVES

This study aimed to assess the effect of photodynamic therapy (PDT) on expression of CASP3, NRAS and HRAS genes at mRNA levels, and apoptosis of head and neck squamous cell carcinoma (HNSCC) cell line.

MATERIALS AND METHODS

In order to complete the present in vitro study, HNSCC cell line (NCBI C196 HN5) purchased from Pasteur Institute. Cells were divided into four groups; Group 1: photodynamic treatment (laser + methylene blue (MB) as photosensitizer), group 2: MB, group 3: laser (with 660 nm wavelength), and group 4: control (without any treatment). To determine the optimal concentration of MB, in a pilot study, toxicity of MB in different concentration was assessed using MTT assay. Cells in group 1, 2 and 3 was treated at optimal concentration of MB (1.6 μg/mL). Gene expression at mRNA levels was assessed after 24 h incubation, using real-time (qRT)-PCR. The expression of BAX and BCL2 genes at the mRNA levels was analyzed to evaluate apoptosis. 2^-ΔΔCt values of BCL2, BAX, CASP3, NRAS, and HRAS in groups was analyzed using ANOVA. Tukey's HSD and Games Howell test was used to compare between two groups.

RESULTS

Over-expression of BAX (p < 0.001), CASP3 (p < 0.001) and down-regulation of BCL2 (p = 0.004), HRAS (p = 0.023) and NRAS (p = 0.045) were noted in group 1 (PDT), compared with the control group. Treatment by laser alone induce down-regulation of CASP3 (p < 0.05), BAX (p < 0.05), BCL2 (p > 0.05), HRAS (p > 0.05) and NRAS (p > 0.05).

CONCLUSION

PDT caused down-regulation of NRAS, HRAS and BCL2 and over-expression of CASP3 and BAX genes at mRNA levels in HNSCC cell line. The present study raises the possibility that the role of MB on BCL2 down-regulation and BAX and CASP3 over-expression was higher than laser alone while it seems that laser alone was more effective than MB in HRAS and NRAS down-regulation.

Severe constipation as the first clinical manifestation in multiple endocrine neoplasia type 2B: a case report and literature review

BACKGROUND

The occurrence of multiple endocrine neoplasia type 2B (MEN2B) in Asians is very rare. In particular, patients with intractable constipation as the main clinical manifestation are even rarer. Atypical clinical manifestations are likely to lead to a diagnostic delay. In this report, we described a case of a delayed diagnosis of MEN2B, and the first clinical manifestation was intractable constipation.

CASE PRESENTATION

A female teenager had suffered from intractable constipation since infancy. Because the colonoscopy and biopsy results from local hospitals did not confirm the presence of congenital megacolon, the girl had been followed up at a local clinic for a long time. The diagnosis was not confirmed until thyroid masses were found in the Pediatric Department of Shanghai Ruijin Hospital when she was 12 years old. According to our detailed evaluation, she suffered from Hirschsprung disease (HD), growth retardation, medullary thyroid carcinoma (MTC) and mucosal neuroma due to a mutation in the RET gene. Thus, the diagnosis of MEN2B was confirmed. Afterward, the girl underwent several surgeries and was still being followed up before the article was published.

CONCLUSION

MEN2B has atypical clinical symptoms in the early stage. Refractory constipation may be the only clinical manifestation that lasts for several years. Therefore, we recommend that early screening and gene sequencing should be performed for patients with severe constipation due to HD to determine the cause of the disease and to improve the survival outcome.

C-myc Contributes to Malignancy of Lung Cancer: A Potential Anticancer Drug Target

Emerging evidence has provided important information on oncoproteins involved in cancer initiation, progression, metastasis, and resistance to current therapies. C-myc, one of the critical oncoproteins, has been shown to be implicated in enhancing the aggressiveness of many cancers, mainly through its ability to increase cancer cell growth and cellular survival mechanisms. Despite the more precise and earlier detection and the availability of better therapies, lung cancer remains the most dreadful cancer as it causes high mortality rate with relatively poor treatment success. In lung cancer, C-myc is frequently dysregulated and associated with unfavorable patient survival. C-myc plays a role in regulation of lung cancer cell behaviors including growth, resistance, death, and dissemination through the activation of cell cycle driving proteins, an increase in the cellular levels of anti-apoptotic proteins, and the modulation of metabolism. Besides, C-myc has been shown to be important for cancer stem cell (CSC) properties. Taken together, targeting as well as inhibiting C-myc could provide promising means for resolving lung cancer. This review emphasizes on the molecular mechanism by which C-myc influences lung cancer growth, metastasis, drug resistance, and CSC maintenance, and suggests the target proteins that may benefit drug discovery and design.

The neural ELAVL protein HuB enhances endogenous proto-oncogene activation

The cytoplasmic distribution of the HuR/ELAVL1 (embryonic lethal abnormal vision 1) protein is recognized as an important prognostic factor of malignant tumors. However, the previous study suggests that exogenous over-expression of HuR is not sufficient for nuclear export. Conversely, the predominantly cytosolic distribution of neuron-specific human ELAV members, including HuB/ELAVL2, HuC/ELAVL3, and HuD/ELAVL4, has been reported. In the present study, we demonstrated the expression of HuB in several types of cancer cells, but expression of HuC and HuD was not observed. In addition, our results indicated that HuR and HuB formed a complex in the cytosolic fraction of cancer cells via the RRM3 region. Ectopic expression of HuB was capable of initiating the cytosolic translocation of HuR from the nucleus to the cytosol. Furthermore, HuB-transduced cancer cells displayed significant nuclear export of HuR, with quantitative PCR experiments revealing the simultaneous upregulation of HIF-1α, c-Fos, c-MYC, and Ets2 basal mRNA expression. Phorbol 12-myristate 13-acetate (PMA)-stimulated HuB-transduced cells demonstrated significantly enhanced activation of endogenous c-Fos and CREB dependent cascades. Finally, co-transfection of HuB with the E1 region of type 5 human adenovirus significantly enhanced E1 transformation activities but that of HuR with the E1 region did not. Collectively, our findings suggest that the neural Hu family protein HuB plays a major role in the activation of memory-related proto-oncogenes.

Tumor protein D52 (isoform 3) interacts with and promotes peroxidase activity of Peroxiredoxin 1 in prostate cancer cells implicated in cell growth and migration

Tumor protein D52 (TPD52) is overexpressed in multiple cancers including prostate cancer due to gene amplification and investigations to understand its role in the pathophysiology of different cancers are continuing. GST pull-down assays and Tandem affinity purification of TPD52 as bait identified novel prey Peroxiredoxin 1 (PRDX1) in prostate cancer (PCa) cells. PRDX1 interaction with TPD52 was confirmed in immunoprecipitation and affinity interaction assays. Mapping of interaction domain indicated that PRDX1 interacts with C-terminal region of TPD52 containing PEST domain between 152 and 179 amino acids, a new binding region of TPD52. Here we show that TPD52 interaction with PRDX1 increased its peroxidase activity and ectopic expression of TPD52 induced dimerization of PRDX1 in PCa cells. Moreover, H₂O₂ exposure evoked the interaction between TPD52 and PRDX1 while depletion of both proteins led to the accumulation of H₂O₂ suggesting peroxidase activity is important to maintain oxidative capacity in PCa cells. We also observed that overexpression or downregulation of TPD52 and PRDX1 individually or together affecting PCa cells growth, survival, and migration. Altogether, our results show a novel interaction partner of TPD52 providing new insights of its functions and ascertain the role of TPD52-PRDX1 interaction in PCa progression.

ELL2 Influences Transcription Elongation, Splicing, Ig Secretion and Growth

ELL2 was previously discovered as a member of the Super Elongation Complex. It is involved in driving the maturation of B cells to plasma cells through shifting patterns of RNA processing, favoring generation of the secretory form of heavy chain immunoglobulin (IgH) associated with plasma cells. ELL2 influences the expression and splicing patterns of more than 4,000 genes in antibody secreting cells. The ELL2 gene has been implicated in cancers such as multiple myeloma and salivary gland carcinoma. A member of the ELL family (ELL1) was recently proven to act as an E3 ubiquitin ligase to known proto-oncogene, c-Myc, through a highly conserved cysteine residue in the C-terminal CEYLH region. Comparison of sequence homology shows this region is conserved between the three members of the ELL family, leading us to hypothesize that the other two ELLs (2 and 3) could serve the same role. In this review, we summarize what is known about ELL2 with respect to its role in driving B cell to plasma cell differentiation as well as its potential role in tumor suppression.

Response to metals treatment of Fra1, a member of the AP-1 transcription factor family, in P. lividus sea urchin embryos

Lithium (Li), Nickel (Ni), and Zinc (Zn) are metals normally present in the seawater, although they can have adverse effects on the marine ecosystem at high concentrations by interfering with many biological processes. These metals are toxic for sea urchin embryos, affecting their morphology and developmental pathways. In particular, they perturb differently the correct organization of the embryonic axes (animal-vegetal, dorso-ventral): Li is a vegetalizing agent and Ni disrupts the dorso-ventral axis, while Zn has an animalizing effect. To deeply address the response of Paracentrotus lividus embryos to these metals, we studied the expression profiling of Pl-Fra transcription factor (TF), relating it to Pl-jun, a potential partner for AP-1 complex formation, and to Pl-MT, known to be an AP-1 target and to have a protective role against heavy metals. The AP-1 TFs are found throughout the animal kingdom and are involved in many cellular events, i.e. cell proliferation and differentiation, immune and stress responses, cancer growth. Here, we isolated the complete Pl-Fra cDNA and showed that Pl-Fra transcript, already present in the unfertilized eggs, was newly synthesized from the blastula stage, while its spatial distribution was mainly observed in skeletogenic cells, similarly to Pl-jun. Interestingly, Pl-Fra expression was induced by the different metals and the induction kinetics revealed its persistent expression during treatments. Moreover, its temporal and spatial behavior in response to the three metals was comparable to that of Pl-jun and Pl-MT. The understanding of AP-1 functions in invertebrates may provide new knowledge about the mechanisms of response to metal injuries, as well as it might lead to acknowledge the TFs as new type of biomarkers for the evaluation of hazards in polluted environment.

Genetic and Epigenetic of Medullary Thyroid Cancer

Medullary thyroid carcinoma (MTC) is an infrequent, calcitonin producing neuroendocrine tumor and initiates from the parafollicular C cells of the thyroid gland. Several genetic and epigenetic alterations are collaterally responsible for medullary thyroid carcinogenesis. In this review article, we shed light on all the genetic and epigenetic hallmarks of MTC. From the genetic perspective, RET, HRAS, and KRAS are the most important genes that are characterized in MTC. From the epigenetic perspective, Ras-association domain family member 1A, telomerase reverse transcriptase promoter methylations, overexpression of histone methyltransferases, EZH2 and SMYD3, and wide ranging increase and decrease in non-coding RNAs can be responsible for medullary thyroid carcinogenesis.

Oxidative stress-mediated p53/p21WAF1/CIP1 pathway may be involved in microcystin-LR-induced cytotoxicity in HepG2 cells

A previous study showed that microcystin-LR (MC-LR) exerted cytotoxicity and induced apoptosis in HepG2 cells. In the present study, we investigated whether oxidative stress-mediated p53/p21^WAF1/CIP1 is involved in this process to further elucidate the mechanism of cytotoxicity induced by MC-LR. Morphological evaluation showed that MC-LR induced time- and dose-dependent cytotoxicity in HepG2 cells. Biochemical assays revealed that MC-LR exposure altered the protein levels of HSP70 and HSP90, generally inhibited superoxide dismutase and catalase, reduced glutathione content, and increased the cellular malondialdehyde level of HepG2 cells, suggesting that MC-LR may induce biochemical disturbance and oxidative stress in HepG2 cells. The protein levels of p-p53 and p21 were markedly increased by MC-LR exposure in a concentration-dependent manner, suggesting that p53 and p21 may be involved in the process. Moreover, we also found that the proto-oncogene c-myc was significantly activated in HepG2 cells following MC-LR exposure, indicating that c-myc in HepG2 cells was potentially involved in response to MC-LR-induced apoptosis. These findings may contribute to further understanding the in vitro molecular mechanism of MC-LR hepatotoxicity.

GAB2 Amplification in Squamous Cell Lung Cancer of Non-Smokers

Lung squamous cell cancer (SCC) is typically found in smokers and has a very low incidence in non-smokers, indicating differences in the tumor biology of lung SCC in smokers and non-smokers. However, the specific mutations that drive tumor growth in non-smokers have not been identified. To identify mutations in lung SCC of non-smokers, we performed a genetic analysis using arrays comparative genomic hybridization (ArrayCGH). We analyzed 19 patients with lung SCC who underwent surgical treatment between April 2005 and April 2015. Clinical characteristics were reviewed, and DNA was extracted from fresh frozen lung cancer specimens. All of copy number alterations from ArrayCGH were validated using The Cancer Genome Atlas (TCGA) copy number variation (CNV) data of lung SCC. We examined the frequency of copy number changes according to the smoking status (non-smoker [n = 8] or smoker [n = 11]). We identified 16 significantly altered regions from ArrayCGH data, three gain and four loss regions overlapped with the TCGA lung squamous cell carcinoma (LUSC) patients. Within these overlapped significant regions, we detected 15 genes that have been reported in the Cancer Gene census. We also found that the proto-oncogene GAB2 (11q14.1) was significantly amplified in non-smokers patients and vice versa in both ArrayCGH and TCGA data. Immunohistochemical analyses showed that GAB2 protein was relatively upregulated in non-smoker than smoker tissues (37.5% vs. 9.0%, P = 0.007). GAB2 amplification may have an important role in the development of lung SCC in non-smokers. GAB2 may represent a potential biomarker for lung SCC in non-smokers.

Effects of ambient PM2.5 on pathological injury, inflammation, oxidative stress, metabolic enzyme activity, and expression of c-fos and c-jun in lungs of rats

Fine particulate matter (PM2.5) exposure is associated with morbidity and mortality induced by respiratory diseases and increases the lung cancer risk. However, the mechanisms therein involved are not yet fully clarified. In this study, the PM2.5 suspensions at different dosages (0.375, 1.5, 6.0, and 24.0 mg/kg body weight) were respectively given to rats by the intratracheal instillation. The results showed that PM2.5 exposure induced inflammatory cell infiltration and hyperemia in the lung tissues and increased the inflammatory cell numbers in bronchoalveolar lavage fluid. Furthermore, PM2.5 significantly elevated the levels of pro-inflammatory mediators including tumor necrosis factor-α (TNF-α), interleukin (IL)-6, IL-1β, and intercellular adhesion molecule 1 (ICAM-1) and the expression of c-fos and c-jun in rat lungs exposed to higher dose of PM2.5. These changes were accompanied by decreases of activities of superoxide dismutase and increases of levels of malondialdehyde, inducible nitric oxide synthase, nitric oxide, cytochrome P450s, and glutathione S-transferase. The results implicated that acute exposure to PM2.5 induced pathologically pulmonary changes, unchained inflammatory and oxidative stress processes, activated metabolic enzyme activity, and enhanced proto-oncogene expression, which might be one of the possible mechanisms by which PM2.5 pollution induces lung injury and may be the important determinants for the susceptibility to respiratory diseases.

Formaldehyde-induced histone H3 phosphorylation via JNK and the expression of proto-oncogenes

Formaldehyde (FA) is a very reactive compound that forms DNA adducts and DNA-protein crosslinks, which are known to contribute to FA-induced mutations and carcinogenesis. Post-translational modifications to histones have recently attracted attention due to their link with cancer. In the present study, we examined histone modifications following a treatment with FA. FA significantly phosphorylated histone H3 at serine 10 (H3S10), and at serine 28 (H3S28), the time-course of which was similar to the phosphorylation of H2AX at serine 139 (γ-H2AX), a marker of DNA double strand breaks. The temporal deacetylation of H3 was observed due to the reaction of FA with the lysine residues of histones. The phosphorylation mechanism was then analyzed by focusing on H3S10. The nuclear distribution of the phosphorylation of H3S10 and γ-H2AX did not overlap, and the phosphorylation of H3S10 could not be suppressed with an inhibitor of ATM/ATR, suggesting that the phosphorylation of H3S10 was independent of the DNA damage response. ERK and JNK in the MAPK pathways were phosphorylated by the treatment with FA, in which the JNK pathway was the main target for phosphorylation. The phosphorylation of H3S10 increased at the promoter regions of c-fos and c-jun, indicating a relationship between FA-induced tumor promotion activity and phosphorylation of H3S10. These results suggested that FA both initiates and promotes cancer, as judged by an analysis of histone modifications.

SRSF2 promotes splicing and transcription of exon 11 included isoform in Ron proto-oncogene

The product of proto-oncogene Ron is a human receptor for the macrophage-stimulating protein (MSP). Upon activation, Ron is able to induce cell dissociation, migration and matrix invasion. Exon 11 skipping of Ron pre-mRNA produces Ron△165 protein that is constitutively active even in the absence of its ligand. Here we show that knockdown of SRSF2 promotes the decrease of exon 11 inclusion, whereas overexpression of SRSF2 promotes exon 11 inclusion. We demonstrate that SRSF2 promotes exon 11 inclusion through splicing and transcription procedure. We also present evidence that reduced expression of SRSF2 induces a decrease in the splicing of both introns 10 and 11; by contrast, overexpression of SRSF2 induces an increase in the splicing of introns 10 and 11. Through mutation analysis, we show that SRSF2 functionally targets and physically interacts with CGAG sequence on exon 11. In addition, we reveal that the weak strength of splice sites of exon 11 is not required for the function of SRSF2 on the splicing of Ron exon 11. Our results indicate that SRSF2 promotes exon 11 inclusion of Ron proto-oncogene through targeting exon 11. Our study provides a novel mechanism by which Ron is expressed.

Oncogenic functions of the transcription factor Nrf2

Nuclear factor E2-related factor 2 (Nrf2) is a transcription factor that controls the expression of a large pool of antioxidant and cytoprotective genes regulating the cellular response to oxidative and electrophilic stress. Nrf2 is negatively regulated by Kelch-like ECH-associated protein 1 (Keap1) and, upon stimulation by an oxidative or electrophilic insult, is rapidly activated by protein stabilization. Owing to its cytoprotective functions, Nrf2 has been traditionally studied in the field of chemoprevention; however, there is accumulated evidence that Keap1/Nrf2 mutations or unbalanced regulation that leads to overexpression or hyperactivation of Nrf2 may participate in tumorigenesis and be involved in chemoresistance of a wide number of solid cancers and leukemias. In addition to protecting cells from reactive oxygen species, Nrf2 seems to play a direct role in cell growth control and is related to apoptosis-regulating pathways. Moreover, Nrf2 activity is connected with oncogenic kinase pathways, structural proteins, hormonal regulation, other transcription factors, and epigenetic enzymes involved in the pathogenesis of various types of tumors. The aim of this review is to compile and summarize existing knowledge of the oncogenic functions of Nrf2 to provide a solid basis for its potential use as a molecular marker and pharmacological target in cancer.

FOXM1 (Forkhead box M1) in tumorigenesis: overexpression in human cancer, implication in tumorigenesis, oncogenic functions, tumor-suppressive properties, and target of anticancer therapy

FOXM1 (Forkhead box M1) is a typical proliferation-associated transcription factor and is also intimately involved in tumorigenesis. FOXM1 stimulates cell proliferation and cell cycle progression by promoting the entry into S-phase and M-phase. Additionally, FOXM1 is required for proper execution of mitosis. In accordance with its role in stimulation of cell proliferation, FOXM1 exhibits a proliferation-specific expression pattern and its expression is regulated by proliferation and anti-proliferation signals as well as by proto-oncoproteins and tumor suppressors. Since these factors are often mutated, overexpressed, or lost in human cancer, the normal control of the foxm1 expression by them provides the basis for deregulated FOXM1 expression in tumors. Accordingly, FOXM1 is overexpressed in many types of human cancer. FOXM1 is intimately involved in tumorigenesis, because it contributes to oncogenic transformation and participates in tumor initiation, growth, and progression, including positive effects on angiogenesis, migration, invasion, epithelial-mesenchymal transition, metastasis, recruitment of tumor-associated macrophages, tumor-associated lung inflammation, self-renewal capacity of cancer cells, prevention of premature cellular senescence, and chemotherapeutic drug resistance. However, in the context of urethane-induced lung tumorigenesis, FOXM1 has an unexpected tumor suppressor role in endothelial cells because it limits pulmonary inflammation and canonical Wnt signaling in epithelial lung cells, thereby restricting carcinogenesis. Accordingly, FOXM1 plays a role in homologous recombination repair of DNA double-strand breaks and maintenance of genomic stability, that is, prevention of polyploidy and aneuploidy. The implication of FOXM1 in tumorigenesis makes it an attractive target for anticancer therapy, and several antitumor drugs have been reported to decrease FOXM1 expression.