A novel crosstalk between CCAR2 and AKT pathway in the regulation of cancer cell proliferation

Identification of host dependency factors involved in SARS-CoV-2 replication organelle formation through proteomics and ultrastructural analysis

IMPORTANCE

Remodeling of the cellular endomembrane system by viruses allows for efficient and coordinated replication of the viral genome in distinct subcellular compartments termed replication organelles. As a critical step in the viral life cycle, replication organelle formation is an attractive target for therapeutic intervention, but factors central to this process are only partially understood. In this study, we corroborate that two viral proteins, nsp3 and nsp4, are the major drivers of membrane remodeling in SARS-CoV-2 infection. We further report a number of host cell factors interacting with these viral proteins and supporting the viral replication cycle, some of them by contributing to the formation of the SARS-CoV-2 replication organelle.

Relationship Between Genetic Polymorphisms in Cell Cycle Regulatory Gene TP53 and Polycystic Ovarian Syndrome: A Case-Control Study and In Silico Analyses

Polycystic ovarian syndrome (PCOS) is a complex endocrine and metabolic condition with several potential causes. Insulin resistance is a hallmark of PCOS that often coexists with hirsutism, hyperandrogenism, being overweight, and hormonal imbalances. The functioning of multiple replication and transcription factors is regulated by tumor suppressor genes (TSGs), which play a crucial role in maintaining genomic integrity and controlling the cell cycle of granulosa cells. In the present study, we examined how three single nucleotide polymorphisms (SNPs) in TP53, a cell cycle regulatory gene, affect the risk of developing PCOS in a sample of an Iranian population. Genomic DNA was extracted from 200 PCOS patients and 200 healthy women to analyze TP53 rs17880604, rs1625895, and rs1042522 SNPs using the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method. Our findings revealed that the majority of PCOS cases were overweight [25 < body mass index (BMI) < 30]. A positive association was observed between the TP53 rs1042522 SNP and the risk of PCOS under codominant heterozygous and overdominant genetic patterns (odds ratio > 1). Meanwhile, a negative association was observed between TP53 SNPs (rs1625895, rs17880604) and susceptibility to PCOS under codominant heterozygous and dominant models of inheritance (odds ratio < 1). Moreover, different genotype and haplotype combinations of rs17880604/rs1625895/rs1042522 conferred a decreased risk of PCOS in our population. We found no statistical difference in the frequency of TP53 genotypes between PCOS cases and/or controls in terms of BMI, waist circumference, prolactin level, and markers of lipid and carbohydrate profile (P > 0.05). Molecular dynamic prediction showed that the missense substitution in the 17p13.1 position (rs1042522) could change the properties and secondary structure of the p53 protein. As inherited risk factors, TP53 variations may play a  pivotal role in the pathogenesis of PCOS among Iranian women. Replicated population-based studies on other ethnicities are required to find the genetic contribution of variants of TP53, or SNPs located in other TSGs, to the etiology of this endocrine disease.

Sex specific regulation of TSPY-Like 2 in the DNA damage response of cancer cells

Females have a lower probability to develop somatic cancers and a better response to chemotherapy than males. However, the reasons for these differences are still not well understood. The X-linked gene TSPY-Like 2 (TSPYL2) encodes for a putative tumor suppressor protein involved in cell cycle regulation and DNA damage response (DDR) pathways. Here, we demonstrate that in unstressed conditions TSPYL2 is maintained at low levels by MDM2-dependent ubiquitination and proteasome degradation. Upon genotoxic stress, E2F1 promotes TSPYL2 expression and protein accumulation in non-transformed cell lines. Conversely, in cancer cells, TSPYL2 accumulates only in females or in those male cancer cells that lost the Y-chromosome during the oncogenic process. Hence, we demonstrate that while TSPYL2 mRNA is induced in all the tested tumor cell lines after DNA damage, TSPYL2 protein stability is increased only in female cancer cells. Indeed, we found that TSPYL2 accumulation, in male cancer cells, is prevented by the Y-encoded protein SRY, which modulates MDM2 protein levels. In addition, we demonstrated that TSPYL2 accumulation is required to sustain cell growth arrest after DNA damage, possibly contributing to protect normal and female cancer cells from tumor progression. Accordingly, TSPYL2 has been found more frequently mutated in female-specific cancers. These findings demonstrate for the first time a sex-specific regulation of TSPYL2 in the DDR of cancer cells and confirm the existence of sexual dimorphism in DNA surveillance pathways.

MiR-342-5p protects neurons from cerebral ischemia induced-apoptosis through regulation of Akt/NF-κB pathways by targeting CCAR2

OBJECTIVES

Ischemic stroke causes high morbidity, mortality and health burden in the world. MiR-342-5p was associated with Alzheimer's disease and cardio-protection. Herein, we aimed to reveal effects of miR-342-5p on cerebral ischemia injury as well as novel targets for stroke.

MATERIALS AND METHODS

AgomiR-342-5p was intracerebroventricularly injected into the middle cerebral artery occlusion (MCAO) mouse models to evaluate functions of miR-342-5p on cerebral ischemia. RT-qPCR and western blot assays were used to evaluate genes expression. Oxygen-glucose deprivation (OGD) was used as an in vitro model for ischemia. Viability and apoptosis ratio of neurons was evaluated by CCK-8, LDH release detection, and flow cytometry. The potential targets of miR-342-5p were predicted by Targetscan, and their interaction was confirmed by luciferase assay.

RESULTS

The intervention of miR-342-5p effectively attenuated ischemic injury in MCAO mice. MiR-342-5p overexpression could protect neurons against OGD-induced injury, as revealed by increased cell viability and BCL2 expression, and decreased LDH release, apoptosis ratio, and BAX expression in OGD-induced neurons. Mechanically, miR-342-5p could directly bound with CCAR2 to inhibit its expression. Overexpressing CARR2 aggravated the OGD-induced injury of neurons, which was partly restrained by overexpressing miR-342-5p reversed. Furthermore, miR-342-5p/CARR2 axis regulates Akt/NF-κB signaling pathway in vitro as well as in vivo cerebral ischemia models.

CONCLUSIONS

MiR-342-5p inhibited neuron apoptosis by regulating Akt/NF-kB signaling pathway via CCAR2 suppression. Our findings revealed the neuroprotection of miR-342-5p in cerebral ischemia.

Interaction of DBC1 with polyoma small T antigen promotes its degradation and negatively regulates tumorigenesis

Deleted in Breast Cancer 1 (DBC1) is an important metabolic sensor. Previous studies have implicated DBC1 in various cellular functions, notably cell proliferation, apoptosis, histone modification, and adipogenesis. However, current reports about the role of DBC1 in tumorigenesis are controversial and designate DBC1 alternatively as a tumor suppressor or a tumor promoter. In the present study, we report that polyoma small T antigen (PyST) associates with DBC1 in mammalian cells, and this interaction leads to the posttranslational downregulation of DBC1 protein levels. When coexpressed, DBC1 overcomes PyST-induced mitotic arrest and promotes the exit of cells from mitosis. Using both transient and stable modes of PyST expression, we also show that cellular DBC1 is subjected to degradation by LKB1, a tumor suppressor and cellular energy sensor kinase, in an AMP kinase-independent manner. Moreover, LKB1 negatively regulates the phosphorylation as well as activity of the prosurvival kinase AKT1 through DBC1 and its downstream pseudokinase substrate, Tribbles 3 (TRB3). Using both transient transfection and stable cell line approaches as well as soft agar assay, we demonstrate that DBC1 has oncogenic potential. In conclusion, our study provides insight into a novel signaling axis that connects LKB1, DBC1, TRB3, and AKT1. We propose that the LKB1–DBC1–AKT1 signaling paradigm may have an important role in the regulation of cell cycle and apoptosis and consequently tumorigenesis.

CCAR2 promotes a malignant phenotype of osteosarcoma through Wnt/β-catenin-dependent transcriptional activation of SPARC

CCAR2 plays a pivotal role in the regulation of the DNA damage response and cancer progression. Although aberrant expression of CCAR2 has been reported in several types of cancer, its biological function and molecular mechanism in osteosarcoma (OS) have not yet been fully elucidated. Here, we show that silence of CCAR2 prevented the malignant phenotype of OS cell in vitro and decreased tumor growth in nude mice. By analyzing the transcriptomic profile of CCAR2 knockdown U2OS cells, we identified secreted protein acidic and rich in cysteine (SPARC) is tightly regulated by CCAR2. Mechanically, we found that SPARC is transcriptionally regulated by Wnt/β-catenin signaling, and CCAR2 acts as a co-activator of Wnt/β-catenin signaling to regulate the expression of SPARC in OS cells. Additionally, SPARC knockdown largely eliminated the malignant phenotype induced by CCAR2 overexpression and forced expression of SPARC promoted the malignant phenotype of CCAR2-depleted cells. In conclusion, our results suggest that CCAR2 exerted oncogenic roles in OS cells mainly via up-regulating SPARC expression and targeting the CCAR2-SPARC axis might have promising application prospect for the treatment of osteosarcoma.

TRIB3 promotes proliferation, migration, and invasion of retinoblastoma cells by activating the AKT/mTOR signaling pathway

BACKGROUND

Tribbles pseudokinase 3 (TRIB3) is a member of the tribbles-related family, which has been determined in various cancers, including renal cell carcinoma, acute promyelocytic leukemia, colorectal cancer, endometrial cancer, and glioma. However, its role in retinoblastoma (RB) has not yet been explored.

METHODS

The expression level of TRIB3 was detected in RB tissues and cell lines using qRT-PCR. The effects of TRIB3 on cell proliferation and invasion capacities were analyzed with MTT, crystal violet, and transwell assays. Western blot and rescue assays were conducted to explore the underlying mechanism.

RESULTS

This study found that TRIB3 was upregulated in human RB tissues compared to adjacent normal tissues both at the mRNA and protein levels. Overexpression of TRIB3 significantly promoted cell proliferation and invasion of RB cells, while TRIB3 knockdown inhibited these processes. Moreover, the mechanism deciphering experiments showed that TRIB3 overexpression can increase AKT and mTOR phosphorylation. Conversely, TRIB3 knockdown decreased the phosphorylation of AKT and mTOR. Additionally, MK2206, a potent AKT inhibitor, blocked the promotive effects of TRIB3 in RB cells.

CONCLUSION

This study demonstrated that TRIB3 acts as an oncogene and plays a crucial role in the proliferation and invasion of RB cells via regulating the AKT/mTOR signaling pathway. Therefore, TRIB3 may serve as a potential target in the diagnosis and/or treatment of RB.

The Effect of Cannabidiol on UV-Induced Changes in Intracellular Signaling of 3D-Cultured Skin Keratinocytes

Human epidermal keratinocytes are constantly exposed to UV radiation. As a result, there is a significant need for safe and effective compounds to protect skin cells against this environmental damage. This study aimed to analyze the effect of phytocannabinoid-cannabinoid (CBD)-on the proteome of UVA/B irradiated keratinocytes. The keratinocytes were cultured in a three-dimensional (3D) system, designed to mimic epidermal conditions closely. The obtained results indicate that CBD protected against the harmful effects of UVA/B radiation. CBD decreased the expression of proinflammatory proteins, including TNFα/NFκB and IκBKB complex and decreased the expression of proteins involved in de novo protein biosynthesis, which are increased in UVA/B-irradiated cells. Additionally, CBD enhanced the UV-induced expression of 20S proteasome subunits. CBD also protected protein structures from 4-hydroxynonenal (HNE)-binding induced by UV radiation, which primarily affects antioxidant enzymes. CBD-through its antioxidant/anti-inflammatory activity and regulation of protein biosynthesis and degradation-protects skin cells against UVA/B-induced changes. In the future, its long-term use in epidermal cells should be investigated.

TRIB3 promotes oral squamous cell carcinoma cell proliferation by activating the AKT signaling pathway

Tribbles pseudokinase 3 (TRIB3), a member of the tribbles-related family, has biological roles such as by acting as an oncogene or tumor suppressor gene, in various types of cancer, including colorectal cancer, breast cancer, lung cancer and renal cell carcinoma. However, the role of TRIB3 in oral squamous cell carcinoma (OSCC) is remains unclear. The current was aimed to determine the biological function of TRIB3 in OSCC progression. TRIB3 expression was examined in OSCC surgical specimens using reverse transcription-quantitative PCR and the role of TRIB3 in the proliferation capacities of OSCC cell lines was examined using crystal violet and MTT assays in vitro and tumorigenicity assays in vivo. The underlying mechanism by which TRIB3 exerts its function was investigated using western blotting. The results demonstrated that the mRNA and protein expression levels of TRIB3 were higher in human OSCC tissues compared with normal tissues. The role of TRIB3 in cell proliferation was also determined. TRIB3 overexpression significantly promoted OSCC cell proliferation, whereas TRIB3 knockdown inhibited OSCC cell proliferation compared with control cells. TRIB3 knockdown also suppressed tumor growth and decreased tumor volume in vivo compared with control cells. Moreover, the results suggested that TRIB3 overexpression increased the phosphorylation of protein kinase B (AKT) and mammalian target of rapamycin (mTOR), whereas TRIB3 knockdown decreased the phosphorylation of AKT and mTOR compared with control cells. To summarize, the present study indicated that TRIB3 promoted OSCC cell proliferation by activating the AKT signaling pathway; therefore, TRIB3 may serve as a potential target for the diagnosis and treatment of OSCC.

CCAR1 and CCAR2 as gene chameleons with antagonistic duality: Preclinical, human translational, and mechanistic basis

Cell Cycle and Apoptosis Regulator 1 (CCAR1) and Cell Cycle and Apoptosis Regulator 2 (CCAR2) have emerged as key players in physiology and pathophysiology, with critical roles in the DNA damage response, nuclear receptor function, and Wnt signaling, among other activities. Contradictory reports exist on the functional duality of CCAR1 and CCAR2 as either tumor promoters or suppressors, suggesting that CCAR1 and CCAR2 have the hallmarks of gene chameleons. We review herein the mechanistic, preclinical, and human translational findings for CCAR1 and CCAR2, based on available RNA and protein expression data from human studies, The Cancer Genome Atlas (TCGA) data mining, gene knockout mouse models, and cell-based assays. Multiple factors contribute to the divergent activities of CCAR1 and CCAR2, including tissue type, mutation/genetic background, protein-protein interactions, dynamic regulation via posttranslational modifications, and alternative RNA splicing. An array of protein partners interact with CCAR1 and CCAR2 in the context of tumor promotion and suppression, including β-catenin, androgen receptor, p21Cip1/Waf1, tumor protein p53 (p53), sirtuin 1, and histone deacetylase 3. Genetic changes frequently found in cancer, such as TP53 mutation, also serve as critical determinants of survival outcomes in cancer patients. This review seeks to provide the impetus for further investigation into CCAR1 and CCAR2 as potential master regulators of metabolism, aging, and cancer.

Proteomics-Based Evidence for a Pro-Oncogenic Role of ESRP1 in Human Colorectal Cancer Cells

The RNA-binding protein, Epithelial Splicing Regulatory Protein 1 (ESRP1) can promote or suppress tumorigenesis depending on the cell type and disease context. In colorectal cancer, we have previously shown that aberrantly high ESRP1 expression can drive tumor progression. In order to unveil the mechanisms by which ESRP1 can modulate cancer traits, we searched for proteins affected by modulation of Esrp1 in two human colorectal cancer cell lines, HCA24 and COLO320DM, by proteomics analysis. Proteins hosted by endogenous ESRP1 ribonucleoprotein complex in HCA24 cells were also analyzed following RNA-immunoprecipitation. Proteomics data were complemented with bioinformatics approach to exploit publicly available data on protein-protein interaction (PPI). Gene Ontology was analysed to identify a common molecular signature possibly explaining the pro-tumorigenic role of ESRP1. Interestingly, proteins identified herein support a role for ESRP1 in response to external stimulus, regulation of cell cycle and hypoxia. Our data provide further insights into factors affected by and entwined with ESRP1 in colorectal cancer.

Functional Compartmentalization of HSP60-Survivin Interaction between Mitochondria and Cytosol in Cancer Cells

Heat shock protein 60 (HSP60) and survivin reside in both the cytosolic and mitochondrial compartments under physiological conditions. They can form HSP60-survivin complexes through protein–protein interactions. Their expression levels in cancer tissues are positively correlated and higher expression of either protein is associated with poor clinical prognosis. The subcellular location of HSP60-survivin complex in either the cytosol or mitochondria is cell type-dependent, while the biological significance of HSP60-survivin interaction remains elusive. Current knowledge indicates that the function of HSP60 partly rests on where HSP60-survivin interaction takes place. HSP60 has a pro-survival function when binding to survivin in the mitochondria through interacting with other factors such as CCAR2 and p53. In response to cell death signals, mitochondrial survivin functions through preventing procaspase activation. Degradation of cytosolic survivin leads to the loss of mitochondrial membrane potential and aberrant mitosis processes. On the other hand, HSP60 release from mitochondria to cytosol upon death stimuli might exert a pro-death function, either through stabilizing Bax, enhancing procaspase-3 activation, or increasing protein ubiquitination. Combining the knowledge of mitochondrial HSP60-survivin complex function, cytosolic survivin degradation effect, and pro-death function upon mitochondria release of HSP60, a hypothetical scenario for HSP60-survivin shuttling upon death stimuli is proposed.

Quantifying Risk Pathway Crosstalk Mediated by miRNA to Screen Precision drugs for Breast Cancer Patients

Breast cancer has become the most common cancer that leads to women's death. Breast cancer is a complex, highly heterogeneous disease classified into various subtypes based on histological features, which determines the therapeutic options. System identification of effective drugs for each subtype remains challenging. In this work, we present a computational network biology approach to screen precision drugs for different breast cancer subtypes by considering the impact intensity of candidate drugs on the pathway crosstalk mediated by miRNAs. Firstly, we constructed and analyzed the subtype-specific risk pathway crosstalk networks mediated by miRNAs. Then, we evaluated 36 Food and Drug Administration (FDA)-approved anticancer drugs by quantifying their effects on these subtype-specific pathway crosstalk networks and combining with survival analysis. Finally, some first-line treatments of breast cancer, such as Paclitaxel and Vincristine, were optimized for each subtype. In particular, we performed precision screening of subtype-specific therapeutic drugs and also confirmed some novel drugs suitable for breast cancer treatment. For example, Sorafenib was applicable for the basal subtype treatment, Irinotecan was optimum for Her2 subtype treatment, Vemurafenib was suitable for the LumA subtype treatment, and Vorinostat could apply to LumB subtype treatment. In addition, the mechanism of these optimal therapeutic drugs in each subtype of breast cancer was further dissected. In summary, our study offers an effective way to screen precision drugs for various breast cancer subtype treatments. We also dissected the mechanism of optimal therapeutic drugs, which may provide novel insight into the precise treatment of cancer and promote researches on the mechanisms of action of drugs.

Integrative Analysis of Cancer Omics Data for Prognosis Modeling

Prognosis modeling plays an important role in cancer studies. With the development of omics profiling, extensive research has been conducted to search for prognostic markers for various cancer types. However, many of the existing studies share a common limitation by only focusing on a single cancer type and suffering from a lack of sufficient information. With potential molecular similarity across cancer types, one cancer type may contain information useful for the analysis of other types. The integration of multiple cancer types may facilitate information borrowing so as to more comprehensively and more accurately describe prognosis. In this study, we conduct marginal and joint integrative analysis of multiple cancer types, effectively introducing integration in the discovery process. For accommodating high dimensionality and identifying relevant markers, we adopt the advanced penalization technique which has a solid statistical ground. Gene expression data on nine cancer types from The Cancer Genome Atlas (TCGA) are analyzed, leading to biologically sensible findings that are different from the alternatives. Overall, this study provides a novel venue for cancer prognosis modeling by integrating multiple cancer types.

TRIB3 suppresses proliferation and invasion and promotes apoptosis of endometrial cancer cells by regulating the AKT signaling pathway

Objective

The aim of this study was to examine the effect of TRIB3 on proliferation, apoptosis, and migration of endometrial cancer (EC) cells and explore the relationship between TRIB3 and AKT signaling pathway in EC progression.

Methods

Immunohistochemical analysis was performed to measure the expression level of TRIB3 in normal endometrium tissues and EC tissues. Overexpression and shRNA knockdown techniques were applied by transfecting EC cells (ISK and AN3CA), and the effect of TRIB3 on EC cell biological behaviors was evaluated. Cell Counting Kit-8 and colony formation assays were utilized to investigate EC cell proliferation ability, and flow cytometry was performed to assess the apoptosis of EC cells. Moreover, the migration and invasion of EC cells were detected by transwell assay, and the levels of MMP-2 and MMP-9 were measured by ELISA. Additionally, Western blot analysis was carried out to determine the levels of AKT and p-AKT.

Results

The expression level of TRIB3 was higher in EC than normal endometrium tissues, and its overexpression promoted apoptosis and suppressed proliferation of EC cells. Furthermore, TRIB3 retarded the migration and invasion of EC cells and decreased the levels of MMP-2 and MMP-9. Conversely, TRIB3 inhibition enhanced the expression levels of MMP-2 and MMP-9, and proliferation and migration of EC cells but suppressed their apoptosis. Similarly, TRIB3 overexpression reduced while its knockdown increased the level of p-AKT.

Conclusion

TRIB3 inhibited proliferation and migration and promoted apoptosis of EC cells probably through regulating AKT signaling pathway.

TSPYL2 is a novel regulator of SIRT1 and p300 activity in response to DNA damage

Protein acetylation and deacetylation events are finely regulated by lysine-acetyl-transferases and lysine-deacetylases and constitute an important tool for the activation or inhibition of specific cellular pathways. One of the most important lysine-acetyl-transferases is p300, which is involved in the regulation of gene expression, cell growth, DNA repair, differentiation, apoptosis, and tumorigenesis. A well-known target of p300 is constituted by the tumor suppressor protein p53, which plays a critical role in the maintenance of genomic stability and whose activity is known to be controlled by post-translational modifications, among which acetylation. p300 activity toward p53 is negatively regulated by the NAD-dependent deacetylase SIRT1, which deacetylates p53 preventing its transcriptional activation and the induction of p53-dependent apoptosis. However, the mechanisms responsible for p53 regulation by p300 and SIRT1 are still poorly understood. Here we identify the nucleosome assembly protein TSPY-Like 2 (TSPYL2, also known as TSPX, DENTT, and CDA1) as a novel regulator of SIRT1 and p300 function. We demonstrate that, upon DNA damage, TSPYL2 inhibits SIRT1, disrupting its association with target proteins, and promotes p300 acetylation and activation, finally stimulating p53 acetylation and p53-dependent cell death. Indeed, in response to DNA damage, cells silenced for TSPYL2 were found to be defective in p53 activation and apoptosis induction and these events were shown to be dependent on SIRT1 and p300 function. Collectively, our results shed new light on the regulation of p53 acetylation and activation and reveal a novel TSPYL2 function with important implications in cancerogenesis.

CCAR2 negatively regulates IL-8 production in cervical cancer cells

Cell cycle and apoptosis regulator 2 (CCAR2) is a multifaceted protein that controls diverse cellular functions; however, its function in cancer is unclear. To better understand its potential role in cancer, we examined gene expression patterns regulated by CCAR2 in cervical cancer cells. Cytokine and chemokine production by CCAR2-deficient cells increased under oxidative conditions. In particular, H₂O₂-treated CCAR2-depleted cells showed a significant increase in interleukin-8 (IL-8) production, indicating a negative regulation of IL-8 by CCAR2. Upregulation of IL-8 expression in CCAR2-deficient cells occurred via activation of transcription factor AP-1. The negative correlation between CCAR2 and IL-8 expression was confirmed by examining mRNA and protein levels in tissues from cervical cancer patients. Furthermore, CCAR2-regulated IL-8 expression is associated with a shorter survival of cervical cancer patients. Overall, the data suggest that CCAR2 plays a critical role in controlling both the cancer secretome and cancer progression.

Human lung epithelial cells A549 epithelial-mesenchymal transition induced by PVA/Collagen nanofiber

Epithelial-mesenchymal transition (EMT) is a process by which epithelial cells lose their cell-cell contact to become mesenchymal stem cells, which is important on development and embryogenesis, wound healing, and cancer metastasis. This research aims to investigate the effect of topological cue as modulating factor on the EMT by tuning the diameter of electrospinning nanofiber. The cell-nanofiber interaction between human lung epithelial cell A549 and electrospinning nanofibers composed of polyvinyl alcohol (PVA) and type I collagen were investigated. The electrospinning of regenerated PVA/Collagen nanofibers were performed with water/acetic acid as a spinning solvent and glutaraldehyde as a chemical cross-linker. Parameterization on concentration, applied voltage and feeding rate was finalized to generate smooth nanofibers with good homogeneity. The scanning electron microscopy result demonstrated that A549 cell appropriately achieved extended morphology by the filopodia attaching to the surface of the nanofibrous mats. When the diameter changed from 90nm to 240nm, the A549 cell was correspondingly express varied EMT related genes. Gene expression analysis was conducted by qPCR using three typical markers for detecting EMT: N-cadherin (NCad), Vimentin (Vim), and Fibronectin (Fib). An increasing expression pattern was observed on cell culturing on 170nm sample with respect to cell cultured on 90nm and 240nm. This result indicated the 170nm PVA/Collagen nanofibers induce A549 cells to process epithelial-mesenchymal transition more seriously than those on 90nm or 240nm.

Electrospinning of PVA/sericin nanofiber and the effect on epithelial-mesenchymal transition of A549 cells

This research aims to investigate the cell-nanomaterial interaction between epithelial-mesenchymal transition of A549 cell and electrospinning nanofibers composed of polyvinyl alcohol (PVA)/silk sericin (SS). The electrospinning of regenerated nanofiber was performed with water as a spinning solvent and glutaraldehyde as a chemical cross-linker. Solution concentration, applied voltage and spin distances as well as other parameters were optimized to generate fine nanofibers with smooth surface in good homogeneity. From the scanning electron microscopy (SEM) analysis, the nanofibers had an average diameter of 200nm. Epithelial-mesenchymal transition (EMT) is a process by which epithelial cells lose their cell polarity to become mesenchymal stem cells. This transition is affected by multiple biochemical and physical factors in cell metabolism cascade. Herein, we investigate the biophysical effect on A549 EMT by culturing cells on nanofibrous mats with different topography and composition. The cell viability was evaluated by biochemical assay and its morphology was observed with SEM. The results demonstrate that cells appropriately attached to the surface of the nanofibrous mats with extended morphology by their filopodia. Gene expression analysis was conducted by real-time PCR using multiple markers for detecting EMT: N-cadherin (NCad), Vimentin (Vim), Fibronectin (Fib) and Matrix metallopeptidase (MMP9). An increasing expression pattern was observed on NCad, Vim, Fib, with respect to a negative control as cell cultured on polystyrene dish. This result indicates the 200nm PVA/SS nanofibers may induce A549 cells to process epithelial-mesenchymal transition during the culturing.