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Apobec-1 complementation factor (A1CF) functions as an RNA-binding cofactor for APO-BEC1-mediated C-to-U conversion during RNA editing and as a hepatocyte-specific regulator in the alternative pre-mRNA splicing of metabolic enzymes. Its role in RNA editing has not been clearly established. Western blot, co-immunoprecipitation (Co-IP), immunofluorescence (IF), methyl thiazolyl tetrazolium (MTT), and 5-ethynyl-2′-deoxyuridine (EdU) assays were used to examine the role of A1CF beyond RNA editing in renal carcinoma cells. We demonstrated that A1CF interacts with NKRF, independent of RNA and DNA, without affecting its expression or nuclear translocation; however, it modulates p65(Ser536) phosphorylation and IFN-β levels. Truncation of A1CF or deletion on NKRF revealed that the RRM1 domain of A1CF and the p65 binding motif of NKRF are required for their interaction. Deletion of RRM1 on A1CF abrogates NKRF binding, and the decrease in IFN-β expression and p65(Ser536) phosphorylation was induced by A1CF. Moreover, full-length A1CF, but not an RRM1 deletion mutant, promoted cell proliferation in renal carcinoma cells. Perturbation of A1CF levels in renal carcinoma cells altered anchorage-independent growth and tumor progression in nude mice. Moreover, p65(Ser536) phosphorylation and IFN-β expression were lower, but ki67 was higher in A1CF-overexpressing tumor tissues of a xenograft mouse model. Notably, primary and metastatic samples from renal cancer patients exhibited high A1CF expression, low p65(Ser536) phosphorylation, and decreased IFN-β levels in renal carcinoma tissues compared with the corresponding paracancerous tissues. Our results indicate that A1CF-decreased p65(Ser536) phosphorylation and IFN-β levels may be caused by A1CF competitive binding to the p65-combined site on NKRF and demonstrate the direct binding of A1CF independent of RNA or DNA in signal pathway regulation and tumor promotion in renal carcinoma cells. [ABSTRACT FROM AUTHOR]

Apobec-1 complementation factor (A1CF) functions as an RNA-binding cofactor for APO-BEC1-mediated C-to-U conversion during RNA editing and as a hepatocyte-specific regulator in the alternative pre-mRNA splicing of metabolic enzymes. Its role in RNA editing has not been clearly established. Western blot, co-immunoprecipitation (Co-IP), immunofluorescence (IF), methyl thiazolyl tetrazolium (MTT), and 5-ethynyl-2′-deoxyuridine (EdU) assays were used to examine the role of A1CF beyond RNA editing in renal carcinoma cells. We demonstrated that A1CF interacts with NKRF, independent of RNA and DNA, without affecting its expression or nuclear translocation; however, it modulates p65(Ser536) phosphorylation and IFN-β levels. Truncation of A1CF or deletion on NKRF revealed that the RRM1 domain of A1CF and the p65 binding motif of NKRF are required for their interaction. Deletion of RRM1 on A1CF abrogates NKRF binding, and the decrease in IFN-β expression and p65(Ser536) phosphorylation was induced by A1CF. Moreover, full-length A1CF, but not an RRM1 deletion mutant, promoted cell proliferation in renal carcinoma cells. Perturbation of A1CF levels in renal carcinoma cells altered anchorage-independent growth and tumor progression in nude mice. Moreover, p65(Ser536) phosphorylation and IFN-β expression were lower, but ki67 was higher in A1CF-overexpressing tumor tissues of a xenograft mouse model. Notably, primary and metastatic samples from renal cancer patients exhibited high A1CF expression, low p65(Ser536) phosphorylation, and decreased IFN-β levels in renal carcinoma tissues compared with the corresponding paracancerous tissues. Our results indicate that A1CF-decreased p65(Ser536) phosphorylation and IFN-β levels may be caused by A1CF competitive binding to the p65-combined site on NKRF and demonstrate the direct binding of A1CF independent of RNA or DNA in signal pathway regulation and tumor promotion in renal carcinoma cells.

What are the specific genetic alterations and associated network in endometriotic cells responsible for the disease pathogenesis? Case control experimental study involving 45 women with endometriosis who underwent laparoscopic surgery (case) and 45 normal samples from women undergoing total abdominal hysterectomy (control). The endometrial samples were subjected to whole exome sequencing (WES) of endometriotic tissue and copy number variation analysis. Validation of gene hits were obtained from WES using polymerase chain reaction techniques, immunological techniques, in-silico tools and transgenic cell line models. Germline heterozygous deletion of mRNA editing enzyme subunit APOBEC3B was identified in about 96% of endometriosis samples. The presence of germline deletion was confirmed with blood, endometrium and normal ovary samples obtained from the same patient. APOBEC3B deletions resulted in a hybrid protein that activates A1CF. APOBEC3B deletion can be a major cause of changes in the endometriotic microenvironment, and contributes to the pathogenesis and manifestation of the disease. The effect of APOBEC3B deletion was proved by in-vitro experiments in a cell line model, which displayed endometriosis-like characteristics. APOBEC3B germline deletion plays a major role in the pathogenesis of endometriosis, which is evident by the activation of A1CF, an increase in epithelial to mesenchymal transition, cellular proliferation, inflammation markers and a decrease in apoptosis markers. The deleterious effects caused by APOBEC3B deletion in endometriosis were identified and confirmed. These results might provide a base for identifying the complete pathogenetic mechanism of endometriosis, thereby moving a step closer to better diagnosis and treatment options. [ABSTRACT FROM AUTHOR]

Background: APOBEC1 complementation factor (A1CF) is a component of the apolipoprotein-B messenger RNA editing complex that participates in various cellular processes and acts as an oncogene in many cancers. In this study, it was aimed to investigate the roles of A1CF and its potential mechanism in endometrial cancer (EC). Materials and Methods: Gene expression prolife was downloaded from The Cancer Genome Atlas database. Then Kaplan-Meier and Cox regression analyses were conducted to assess the prognostic value of A1CF in EC. Cell Counting Kit-8, plate clone formation, and transwell assays were used to estimate the functions of A1CF on the proliferation, invasion, and migration of EC cell. The gene set enrichment analysis was used to analyze the pathway that is enriched by A1CF, whereas quantitative real-time polymerase chain reaction and Western blot analyses were utilized to detect the mRNA and protein expression involved. Results: It was detected that the upregulated A1CF was enriched in P53/P21 signaling pathway and tightly associated with patients' age, stage, and death. Besides, high A1CF expression led to a shorter overall survival of patients and predicted a poor prognosis in EC. The overexpression of A1CF promoted the proliferation, invasion, and migration of EC cells, whereas the depletion of A1CF suppressed these processes. Moreover, P21 and P53 were reduced whereas cyclin D1 and proliferating cell nuclear antigen were induced along with the increasing of A1CF. However, the effects of silencing A1CF on these protein expressions were on the contrary. Conclusion:A1CF was highly expressed and closely related to the prognosis and progression of EC through the regulation of P53/P21 signaling pathway, providing a possible new therapy target site for EC. [ABSTRACT FROM AUTHOR]

Abstract Despite the success and fast adaptation of deep learning models in biomedical domains, their lack of interpretability remains an issue. Here, we introduce Enhanced Integrated Gradients (EIG), a method to identify significant features associated with a specific prediction task. Using RNA splicing prediction as well as digit classification as case studies, we demonstrate that EIG improves upon the original Integrated Gradients method and produces sets of informative features. We then apply EIG to identify A1CF as a key regulator of liver-specific alternative splicing, supporting this finding with subsequent analysis of relevant A1CF functional (RNA-seq) and binding data (PAR-CLIP).

Abstract Background Glioma is the most common and lethal type of malignant brain tumor. Accumulating evidence has highlighted that RNA binding protein APOBEC1 complementation factor (A1CF) is involved in various cellular processes by modulating RNA expression, and acts as an oncogene in breast cancer. However, the function of A1CF in glioma remained unclear. Methods Quantitative RT-PCR and western blot analysis were employed to detect the expression levels of A1CF, lncRNA family with sequence similarity 224 member A (FAM224A), miR-590-3p, zinc finger protein 143 (ZNF143) and ArfGAP with SH3 domain, ankyrin repeat and PH domain 3 (ASAP3) in glioma tissues and cell lines. The Cell Counting Kit-8 assay, migration and invasion assays, and flow cytometry analysis were conducted to evaluate the function of A1CF, FAM224A, miR-590-3p, ZNF143 and ASAP3 in the malignant biological behaviors of glioma cells. Moreover, luciferase reporter, RIP and ChIP assays were used to investigate the interactions among A1CF, FAM224A, miR-590-3p, ZNF143, ASAP3 and MYB. Finally, the xenograft tumor growth assay further ascertained the biological roles of A1CF, FAM224A and miR-590-3p in glioma cells. Results A1CF was upregulated and functioned as an oncogene via stabilizing and increasing FAM224A expression; moreover, high A1CF and FAM224A expression levels indicated a poorer prognosis for glioma patients. Conversely, miR-590-3p was downregulated and exerted a tumor-suppressive function in glioma cells. Inhibition of A1CF significantly restrained cell proliferation, migration and invasion, and promoted apoptosis by upregulating miR-590-3p in a FAM224A-dependent manner. FAM224A was a molecular sponge of miR-590-3p and they were in an RNA-induced silencing complex. ZNF143 was upregulated in glioma tissues and cell lines. MiR-590-3p could negatively modulate the expression of ZNF143 via binding to the ZNF143 3′ UTR. Moreover, ZNF143 participated in miR-590-3p-induced tumor-suppressive activity on glioma cells. ASAP3 and MYB were transcriptionally activated by ZNF143, and importantly, ZNF143 could directly target the promoter of FAM224A and stimulate its expression, collectively forming a positive feedback loop. Conclusions The present study clarifies that the A1CF-FAM224A-miR-590-3p-ZNF143 positive feedback loop conducts critical regulatory effects on the malignant progression of glioma cells, which provides a novel molecular target for glioma therapy.

Metastasis is inevitable in about 30% of patients with primary renal cell carcinoma after nephrectomy treatment. APOBEC1 complementation factor (A1CF), an RNA binding protein, participates in tumor progressions such as growth, apoptosis, differentiation, and invasion. Here, we explored biological functions of A1CF and provided a new insight into renal cell carcinoma metastasis. Wound healing assay was conducted to detect migration in A1CF overexpression and knockdown stable cell lines. Quantitative PCR and western blot assays were utilized to test transcriptional and translation levels of A1CF and SMAD3 in A1CF overexpression and knockdown renal carcinoma cells. Nuclear and cytoplasmic protein separation assays were conducted to evaluate the subcellular distribution of A1CF and SMAD3. Immunoprecipitation assay was conducted to detect the interaction between A1CF and SMAD3. Our study demonstrated A1CF overexpression facilitated cell migration in renal carcinoma cells. A1CF deficiency downregulated expression of SMAD3, Snail1, and N-cadherin. In addition, A1CF promoted nucleus translocation of SMAD3 and interacted with SMAD3. SMAD3 knockdown attenuated cell migration induced by A1CF overexpression. Our study suggested A1CF facilitated cell migration by promoting nucleus translocation of SMAD3 in renal cell carcinoma cells. [ABSTRACT FROM AUTHOR]

A1CF, a complementary factor of APOBEC-1, is involved in many cellular processes for its mRNA editing role, such as cell proliferation, apoptosis, and migration. Here, we explored the regulatory function of A1CF in Wilms tumor-derived cells. Quantitative real-time PCR was performed to detect the mRNA level of A1CF, Axin2, β-Catenin, CCND1 or NKD1 in A1CF-depleted or A1CF-overexpression G401 cells. Western bolt was used to analyze the expression of A1CF, Axin2, and β-catenin protein. The cell apoptosis and migration ability were determined using flow cytometry assay or wound healing, respectively. Our study demonstrated that overexpression of A1CF, Axin2 was upregulated and knockdown of A1CF decreased Axin2 expression at mRNA and protein levels in G401 cells. Besides, knockdown of A1CF further upregulated β-catenin, the classical regulator of Wnt signal pathway, and increased CCND1 and NKD1, the target genes of Wnt/β-catenin. Furthermore, overexpression of Axin2 partly rescued the expression of β-catenin in A1CF-deficiency stable G401 cells. In Wnt agonist BML-284 treated G401 cells, A1CF was increased like other classical regulator of Wnt signal pathway, such as Axin2 and β-catenin. Meanwhile, knockdown of Axin2 rescued β-catenin expression which was decreased in A1CF overexpression condition with BML-284. Further, overexpression of A1CF reduced cell apoptosis but promoted cell migration, and overexpression of Axin2 got similar results. In A1CF-decreased stable G401 cells, overexpression of Axin2 partly rescued the cell apoptosis and migration. We find that A1CF is a positive regulator of Axin2, a Wnt/β-catenin pathway inhibitor, and A1CF-Axin2 signal axis regulates Wilms tumor-derived cells' apoptosis and migration through Axin2. [ABSTRACT FROM AUTHOR]

Transgenic mice expressing a tamoxifen-inducible Cre recombinase specifically in cardiomyocytes were generated in 2001 and are in widespread use, having been employed in >150 published studies. However, several groups recently have reported that tamoxifen administration to these mice can have off-target effects that include cardiac dysfunction, fibrosis, and death. For this reason, among others, we considered it important to better characterize the transgene (termed herein, CM-MCM) and its chromosomal location(s). Cytogenetic analysis positioned the CM-MCM transgene within the C band of chromosome 19, and more precise mapping, using genome walking and DNA sequencing, showed that transgene insertion is in the C1 region. Using the genome walking data, we have developed PCR assays that not only identify mice that carry the transgene, but also distinguish homozygous animals (CM-MCM) from hemizygous (CM-MCM), permitting the rapid assessment of transgene zygosity and, thereby, helping to minimize off-target tamoxifen-induced effects. Substantial rearrangement/duplication of transgene elements is present, and transgene integration was accompanied by the deletion of a 19,500 bp fragment of genomic DNA that contains the promoter, exon 1 and part of intron 1 of the APOBEC1 complementation factor (A1cf) gene, as well as several elements that are predicted to regulate chromosomal architecture. A1cf protein expression is ablated by the deletion and, therefore, homozygous mice are functionally A1cf knockout. The implications of this unexpected finding are discussed. [ABSTRACT FROM AUTHOR]

Testicular tumors, the most common cancer in young men, arise from abnormalities in germ cells during fetal development. Unconventional inheritance for testicular germ cell tumor (TGCT) risk both in humans and mice implicates epigenetic mechanisms. Apolipoprotein B mRNA-editing enzyme complex 1 (APOBEC1) cytidine deaminase and Deadend-1, which are involved in C-to-U RNA editing and microRNA-dependent mRNA silencing, respectively, are potent epigenetic modifiers of TGCT susceptibility in the genetically predisposed 129/Sv inbred mouse strain. Here, we show that partial loss of either APOBEC1 complementation factor (A1CF), the RNA-binding cofactor of APOBEC1 in RNA editing, or Argonaute 2 (AGO2), a key factor in the biogenesis of certain noncoding RNAs, modulates risk for TGCTs and testicular abnormalities in both parent-of-origin and conventional genetic manners. In addition, non-Mendelian inheritance was found among progeny of A1cf and Ago2 mutant intercrosses but not in backcrosses and without fetal loss. Together these findings suggest nonrandom union of gametes rather than meiotic drive or preferential lethality. Finally, this survey also suggested that A1CF contributes to long-term reproductive performance. These results directly implicate the RNA-binding proteins A1CF and AGO2 in the epigenetic control of germ-cell fate, urogenital development, and gamete functions. [ABSTRACT FROM AUTHOR]

Apobec-1 complementation factor (A1CF) is a member of the heterogeneous nuclear ribonucleoproteins (hnRNP) family, which participates in site-specific posttranscriptional RNA editing of apolipoprotein B (apoB) transcript. The posttranscriptional editing of apoB mRNA by A1CF in the small intestine is required for lipid absorption. Apart from the intestine, A1CF mRNA is also reported to be highly expressed in the kidneys. However, it is remained unknown about the functions of A1CF in the kidneys. The aim of this paper is to explore the potential functions of A1CF in the kidneys. Our results demonstrated that in C57BL/6 mice A1CF was weakly expressed in embryonic kidneys from E15.5dpc while strongly expressed in mature kidneys after birth, and it mainly existed in the tubules of inner cortex. More importantly, we identified A1CF negatively regulated the process of epithelial-mesenchymal transition (EMT) in kidney tubular epithelial cells. Our results found ectopic expression of A1CF up-regulated the epithelial markers E-cadherin, and down-regulated the mesenchymal markers vimentin and α-smooth muscle actin (α-SMA) in NRK52e cells. In addition, knockdown of A1CF enhanced EMT contrary to the overexpression effect. Notably, the two A1CF variants led to the similar trend in the EMT process. Taken together, these data suggest that A1CF may be an antagonistic factor to the EMT process of kidney tubular epithelial cells. [ABSTRACT FROM AUTHOR]

• A1CF increases DKK1 expression and activates ERK pathway. • A1CF promotes proliferation and colony formation of 786-O cells. • A1CF activates ERK signaling pathway via DKK1. • A1CF-DKK1 signal axis promotes RCC cell proliferation through ERK signaling. The function and mechanism of RNA editing proteins have been extensively studied, but its association with cellular processes and signaling pathways remained unaddressed. Here, we explored the function of RNA editing complementary protein- Apobec-1 Complementation Factor (A1CF) in the proliferation and colony formation of renal cell carcinoma (RCC) cells. Decreased A1CF expression inhibits the proliferation and colony formation of 786-O cells; and further signaling pathway screening demonstrated that A1CF increases ERK activation and DKK1 expression. Moreover, knockdown of DKK1 has similar phenotypes with A1CF deficiency in 786-O cells on cell proliferation and colony formation and ERK activation. Decreasing of DKK1 expression reduces the phosphorylation of ERK1/2 and MEK1/2 increased by A1CF overexpression; further, inhibiting of the phosphorylation of MEK1/2 by U0126 also decreases the ERK activation upregulated by A1CF overexpression. Deficiency of DKK1 or U0126 treatment suppresses the cell proliferation promoted by A1CF overexpression in 786-O cells; furthermore, U0126 treatment inhibits DKK1-increased cell proliferation in 786-O cells. Our results reveal that DKK1 mediates A1CF to activate ERK in promotion renal carcinoma cell proliferation and colony formation. For the important function of ERK signaling pathway in tumor metastasis and key position of DKK1 in Wnt signaling pathway, we associate RNA editing protein-A1CF with multiple cellular processes and signaling pathways through DKK1, and the key node of A1CF-DKK1-MEK/ERK axis is a potential targeting site for RCC therapy. [ABSTRACT FROM AUTHOR]

Population genetic studies highlight a missense variant (G398S) of A1CF that is strongly associated with higher levels of blood triglycerides (TGs) and total cholesterol (TC). Functional analyses suggest that the mutation accelerates the secretion of very low-density lipoprotein (VLDL) from the liver by an unknown mechanism. Here, we used multiomics approaches to interrogate the functional difference between the WT and mutant A1CF. Using metabolomics analyses, we captured the cellular lipid metabolite changes induced by transient expression of the proteins, confirming that the mutant A1CF is able to relieve the TG accumulation induced by WT A1CF. Using a proteomics approach, we obtained the interactomic data of WT and mutant A1CF. Networking analyses show that WT A1CF interacts with three functional protein groups, RNA/mRNA processing, cytosolic translation, and, surprisingly, mitochondrial translation. The mutation diminishes these interactions, especially with the group of mitochondrial translation. Differential analyses show that the WT A1CF-interacting proteins most significantly different from the mutant are those for mitochondrial translation, whereas the most significant interacting proteins with the mutant are those for cytoskeleton and vesicle-mediated transport. RNA-seq analyses validate that the mutant, but not the WT, A1CF increases the expression of the genes responsible for cellular transport processes. On the contrary, WT A1CF affected the expression of mitochondrial matrix proteins and increased cell oxygen consumption. Thus, our studies confirm the previous hypothesis that A1CF plays broader roles in regulating gene expression. The interactions of the mutant A1CF with the vesicle-mediated transport machinery provide mechanistic insight in understanding the increased VLDL secretion in the A1CF mutation carriers.

The regulation of hepatic gene expression has been extensively studied at the transcriptional level; however, the control of metabolism through posttranscriptional gene regulation by RNA-binding proteins in physiological and disease states is less understood. Here, we report a major role for the hormone-sensitive RNA-binding protein (RBP) APOBEC1 complementation factor (A1CF) in the generation of hepatocyte-specific and alternatively spliced transcripts. Among these transcripts are isoforms for the dominant and high-affinity fructose-metabolizing ketohexokinase C and glycerol kinase, two key metabolic enzymes that are linked to hepatic gluconeogenesis and found to be markedly reduced upon hepatic ablation of A1cf. Consequently, mice lacking A1CF exhibit improved glucose tolerance and are protected from fructose-induced hyperglycemia, hepatic steatosis, and development of obesity. Our results identify a previously unreported function of A1CF as a regulator of alternative splicing of a subset of genes influencing hepatic glucose production through fructose and glycerol metabolism. • A1CF regulates alternative splicing of liver-enriched transcripts • A1CF is required for the high-activity ketohexokinase-C (KHK-C) isoform • Antagonistic actions of hnRNPH1/2 and A1CF mediate KHK-A/KHK-C switch • A1CF regulates fructolysis and glucose production in the liver Nikolaou et al. demonstrate that the RNA-binding protein A1CF regulates the alternative splicing of liver-enriched transcripts, including the metabolic enzymes ketohexokinase (KHK) and glycerol kinase. A1CF antagonizes hnRNPH1/2, thereby controlling the generation of the KHK-A/C isoform, and influences hepatic lipogenesis and glucose production by regulating fructose and glycerol metabolism. [ABSTRACT FROM AUTHOR]

Mammalian C to U RNA is mediated by APOBEC1, the catalytic deaminase, together with RNA binding cofactors (including A1CF and RBM47) whose relative physiological requirements are unresolved. Although A1CF complements APOBEC1 for in vitro RNA editing, A1cf -/- mutant mice exhibited impaired intestinal RNA editing of apoB as well as other targets. Here we examined the role of A1CF and RBM47 in adult mouse liver and intestine, following deletion of either one or both gene products and also following forced (liver or intestinal) transgenic A1CF expression. There were minimal changes in hepatic and intestinal apoB RNA editing in Rbm47 mice and no changes in either liver- or intestine-specific A1CF transgenic mice. A1cf -/- mice and no changes in either liver- or intestine-specific A1CF transgenic mice. Rbm47 liver-specific knockout ( Rbm47 LKO ) mice demonstrated reduced editing in a subset (11 of 20) of RNA targets, including apoB. By contrast, apoB RNA editing was virtually eliminated (<6% activity) in intestine-specific ( Rbm47 IKO ) mice with only five of 53 targets exhibiting C-to-U RNA editing. Double knockout of A1cf mice. These data suggest that A1CF and RBM47 each function independently, yet interact in a tissue-specific manner, to regulate the activity and site selection of APOBEC1 dependent C-to-U RNA editing.Rbm47 in liver ( AR LKO ) eliminated apoB RNA editing and reduced editing in the majority of other targets, with no changes following adenoviral APOBEC1 administration. Intestinal double knockout mice ( AR IKO ) demonstrated further reduced editing (<10% activity) in four of five of the residual APOBEC1 targets identified in AR IKO mice. These data suggest that A1CF and RBM47 each function independently, yet interact in a tissue-specific manner, to regulate the activity and site selection of APOBEC1 dependent C-to-U RNA editing., (© 2019 Blanc et al.; Published by Cold Spring Harbor Laboratory Press for the RNA Society.)

Apobec-1 complementation factor (A1CF) is a member of the heterogeneous nuclear ribonucleoproteins (hnRNP) family, which participates in site-specific posttranscriptional RNA editing of apolipoprotein B (apoB) transcript. The posttranscriptional editing of apoB mRNA by A1CF in the small intestine is required for lipid absorption. Apart from the intestine, A1CF mRNA is also reported to be highly expressed in the kidneys. However, it is remained unknown about the functions of A1CF in the kidneys. The aim of this paper is to explore the potential functions of A1CF in the kidneys. Our results demonstrated that in C57BL/6 mice A1CF was weakly expressed in embryonic kidneys from E15.5dpc while strongly expressed in mature kidneys after birth, and it mainly existed in the tubules of inner cortex. More importantly, we identified A1CF negatively regulated the process of epithelial-mesenchymal transition (EMT) in kidney tubular epithelial cells. Our results found ectopic expression of A1CF up-regulated the epithelial markers E-cadherin, and down-regulated the mesenchymal markers vimentin and α-smooth muscle actin (α-SMA) in NRK52e cells. In addition, knockdown of A1CF enhanced EMT contrary to the overexpression effect. Notably, the two A1CF variants led to the similar trend in the EMT process. Taken together, these data suggest that A1CF may be an antagonistic factor to the EMT process of kidney tubular epithelial cells.