TUFT1 promotes metastasis and chemoresistance in triple negative breast cancer through the TUFT1/Rab5/Rac1 pathway

Tuftelin1 drives experimental pulmonary fibrosis progression by facilitating stress fiber assembly

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is a progressive interstitial lung disease (ILD) with unknown etiology, characterized by sustained damage repair of epithelial cells and abnormal activation of fibroblasts, the underlying mechanism of the disease remains elusive.

METHODS

To evaluate the role of Tuftelin1 (TUFT1) in IPF and elucidate its molecular mechanism. We investigated the level of TUFT1 in the IPF and bleomycin-induced mouse models and explored the influence of TUFT1 deficiency on pulmonary fibrosis. Additionally, we explored the effect of TUFT1 on the cytoskeleton and illustrated the relationship between stress fiber and pulmonary fibrosis.

RESULTS

Our results demonstrated a significant upregulation of TUFT1 in IPF and the bleomycin (BLM)-induced fibrosis model. Disruption of TUFT1 exerted inhibitory effects on pulmonary fibrosis in both in vivo and in vitro. TUFT1 facilitated the assembly of microfilaments in A549 and MRC-5 cells, with a pronounced association between TUFT1 and Neuronal Wiskott-Aldrich syndrome protein (N-WASP) observed during microfilament formation. TUFT1 can promote the phosphorylation of tyrosine residue 256 (Y256) of the N-WASP (pY256N-WASP). Furthermore, TUFT1 promoted transforming growth factor-β1 (TGF-β1) induced fibroblast activation by increasing nuclear translocation of pY256N-WASP in fibroblasts, while wiskostatin (Wis), an N-WASP inhibitor, suppressed these processes.

CONCLUSIONS

Our findings suggested that TUFT1 plays a critical role in pulmonary fibrosis via its influence on stress fiber, and blockade of TUFT1 effectively reduces pro-fibrotic phenotypes. Pharmacological targeting of the TUFT1-N-WASP axis may represent a promising therapeutic approach for pulmonary fibrosis.

Integrin β4 promotes DNA damage-related drug resistance in triple-negative breast cancer via TNFAIP2/IQGAP1/RAC1

Anti-tumor drug resistance is a challenge for human triple-negative breast cancer (TNBC) treatment. Our previous work demonstrated that TNFAIP2 activates RAC1 to promote TNBC cell proliferation and migration. However, the mechanism by which TNFAIP2 activates RAC1 is unknown. In this study, we found that TNFAIP2 interacts with IQGAP1 and Integrin β4. Integrin β4 activates RAC1 through TNFAIP2 and IQGAP1 and confers DNA damage-related drug resistance in TNBC. These results indicate that the Integrin β4/TNFAIP2/IQGAP1/RAC1 axis provides potential therapeutic targets to overcome DNA damage-related drug resistance in TNBC.

RAB5C, a new mRNA binding target of HuR, regulates breast cancer cell proliferation

The posttranscriptional control of gene expression mediated by RNA-binding proteins (RBPs) is essential to determine tumor cell fate. HuR is an RBP with increased expression in various cancer types. This study aimed to clarify the regulatory mechanism of HuR's contribution to breast cancer (BC) cell proliferation by inducing RAB5C expression. First, we analyzed the expression level of HuR and RAB5C in BC tissues and cell lines by immunohistochemistry, qRT-PCR, and western blot. Next, to further investigate the effect of HuR on RAB5C expression, we used short hairpin RNAs (shRNAs) to silence endogenous HuR expression in BC cell lines MCF7 and MDA-MB-231. The binding site of RAB5C mRNA and HuR was confirmed by RNA immunoprecipitation. Finally, the function of RAB5C was investigated using flow cytometry, colony formation, and MTT assays. We found that the expression of HuR and RAB5C was significantly upregulated in BC tissues and MCF-7 and MDA-MB231 cell lines. Importantly, RAB5C mRNA stability was increased through binding of HuR to its 3'UTR. Inhibition of HuR expression using shRNA decreased RAB5C mRNA, suggesting that HuR plays a role in regulating RAB5C expression level. In addition, suppression of RAB5C expression reduced BC cell growth. These results suggest RAB5C functions as an oncogene in BC cells, HuR promoted BC cell survival by facilitating RAB5C expression. Our findings suggest that HuR and RAB5C play important roles in BC cell survival.

SUMOylation of TUFT1 is essential for gastric cancer progression through AKT/mTOR signaling pathway activation

Tuftelin (TUFT1) is highly expressed in various tumor types and promotes tumor growth and metastasis by activating AKT and other core signaling pathways. However, the effects of post-translational modifications of TUFT1 on its oncogenic function remain unexplored. In this study, we found that TUFT1 was SUMOylated at K79. SUMOylation deficiency significantly impaired the ability of TUFT1 to promote the proliferation, migration, and invasion of gastric cancer (GC) cells by blocking AKT/mTOR signaling pathway activation. SUMOylation of TUFT1 is mediated by the E3 SUMO ligase tripartite motif-containing protein 27 (TRIM27), and these two proteins regulate the malignant behavior of GC cells and AKT activation in the same pathway. TUFT1 binds to TRIM27 through its N-terminus, and decreased binding affinity of TUFT1 to TRIM27 significantly impairs its oncogenic effect. In addition, data collected from GC clinical samples indicated that the combined detection of TUFT1 and TRIM27 expression reflected tumor malignancy and patient survival with higher precision. In addition, we proved that SUMOylated TUFT1 is not only an upstream signal for AKT activation but also directly activates mTOR by forming a complex with Rab GTPase activating protein 1, which further inhibits Rab GTPases and promotes the perinuclear accumulation of mTORC1. Altogether, these data indicate that SUMOylated TUFT1 is the active form that affects GC progression through the AKT/mTOR signaling pathway and might be a promising therapeutic target or biomarker for GC progression.

Tuftelin 1 Facilitates Hepatocellular Carcinoma Progression through Regulation of Lipogenesis and Focal Adhesion Maturation

Hepatocellular carcinoma (HCC) is the most common type of primary liver malignancy with poor prognosis worldwide. Emerging evidences demonstrated critical roles of lipid de novo synthesis in HCC progression, yet its regulatory mechanisms are not fully understood. Herein, we found that tuftelin 1 (TUFT1), an acidic phosphorylated glycoprotein with secretory capacity, was significantly upregulated in HCC and had an excellent correlation with patient survival and malignancy features. Through database mining and experimental validation, we found that TUFT1 was associated with fatty acid metabolism and promoted lipid accumulation in HCC cells. Further, we found that TUFT1 can interact with CREB1, a transcription factor for hepatic lipid metabolism, and regulate its activity and the transcriptions of key enzymes for lipogenesis. TUFT1 promoted HCC cell proliferation significantly, which was partially reversed by treatment of an inhibitor of CREB1, KG-501. Moreover, TUFT1 promoted the capacity of HCC cell invasion in vitro, which was likely mediated by its association with zyxin, a zinc-binding phosphoprotein responsible for the formation of fully mature focal adhesions on extracellular matrix. We found that TUFT1 can interact with ZYX and inhibit its expression and recruitments to focal complexes in HCC cells. Collectively, our study uncovered new regulatory mechanisms of TUFT1-mediated lipogenesis, cell proliferation, and invasion.

ATF2 accelerates the invasion and metastasis of hepatocellular carcinoma through targeting the miR-548p/TUFT1 axis

AIM

Due to high invasion and metastasis, hepatocellular carcinoma (HCC) is known as one of the most fatal carcinomas. We aim to further investigate regulatory mechanisms of invasion and metastasis to elucidate HCC pathogenesis and develop novel medications.

METHODS

Patient specimens were collected for assessing gene expression and correlation between gene expressions. The expression of Ki67 and E-cadherin in subcutaneous xenograft tumor were examined by immunohistochemistry staining. The expression of activating transcription factor 2 (ATF2), miR-548p and TUFT1 were determined using Real-time quantitative reverse transcription polymerase chain reaction. Epithelial-mesenchymal transition and PI3K/AKT signaling-associated markers were examined with western blot. The proliferation, migration and invasion were assessed by 3-(4, 5-dimethylthiazolyl-2)-2, 5-diphenyltetrazolium bromide, colony formation and transwell assays, respectively. Cell apoptosis was assessed via Annexin V and propidium iodide staining. Gene interaction was confirmed using chromatin immunoprecipitation and luciferase activity assays. Subcutaneous and intravenous xenograft mouse models were established for analyzing HCC growth and metastasis in vivo.

RESULTS

ATF2 was up-regulated in HCC patients and cells. ATF2 promoted HCC cell proliferation, migration and invasion and inhibited cell apoptosis through directly targeting miR-548p and controlling its expression. miR-548p suppressed HCC cell proliferation, migration and invasion and enhanced cell apoptosis. miR-548p directly bound to the 3'UTR of TUFT1 to restrain its expression and subsequently suppress the PI3K/AKT signaling. ATF2 knock-down significantly suppressed the growth and metastasis of HCC.

CONCLUSION

ATF2 accelerates HCC progression by promoting cell proliferation, migration, invasion and metastasis, which is dependent on regulating the miR-548p/TUFT1 axis.

Identification of a Novel Epithelial-Mesenchymal Transition-Related Gene Signature for Endometrial Carcinoma Prognosis

(1) Background: Endometrial cancer is the most prevalent cause of gynecological malignant tumor worldwide. The prognosis of endometrial carcinoma patients with distant metastasis is poor. (2) Method: The RNA-Seq expression profile and corresponding clinical data were downloaded from the Cancer Genome Atlas database and the Gene Expression Omnibus databases. To predict patients’ overall survival, a 9 EMT-related genes prognosis risk model was built by machine learning algorithm and multivariate Cox regression. Expressions of nine genes were verified by RT-qPCR. Responses to immune checkpoint blockades therapy and drug sensitivity were separately evaluated in different group of patients with the risk model. (3) Endometrial carcinoma patients were assigned to the high- and low-risk groups according to the signature, and poorer overall survival and disease-free survival were showed in the high-risk group. This EMT-related gene signature was also significantly correlated with tumor purity and immune cell infiltration. In addition, eight chemical compounds, which may benefit the high-risk group, were screened out. (4) Conclusions: We identified a novel EMT-related gene signature for predicting the prognosis of EC patients. Our findings provide potential therapeutic targets and compounds for personalized treatment. This may facilitate decision making during endometrial carcinoma treatment.

Hsa_circ_0074269-mediated Upregulation of TUFT1 Through miR-485-5p Increases Cisplatin Resistance in Cervical Cancer

Most cervical cancer patients are prone to developing acquired cisplatin (DDP) resistance. Hsa_circ_0074269 (circ_0074269) plays a promoting role in cervical cancer, but whether circ_0074269 mediates cervical cancer resistance to DDP is unclear. Expression of circ_0074269 was detected by real-time quantitative polymerase chain reaction (RT-qPCR). The half-maximal inhibitory concentration (IC₅₀) value, viability, proliferation, colony formation, migration, and apoptosis of DDP-resistant cervical cancer cells were determined. The molecular mechanisms associated with circ_0074269 were predicted by bioinformatics analysis and confirmed by dual-luciferase reporter and RIP assays. Xenograft assay was conducted to validate the effect of circ_0074269 on DDP resistance in vivo. Exosomes were isolated by ultracentrifugation. Circ_0074269 was overexpressed in DDP-resistant cervical cancer samples and cells. Silencing of circ_0074269 elevated DDP sensitivity, repressed DDP-resistant cervical cancer cell proliferation, and induced DDP-resistant cervical cancer cell apoptosis in vivo and in vitro and curbed DDP-resistant cervical cancer cell migration in vitro. And circ_0074269 could regulate DDP resistance via regulating TUFT1 expression via sponging miR-485-5p. More strikingly, circ_0074269 was also overexpressed in exosomes from DDP-resistant cervical cancer cells, and circ_0074269 could be delivered via exosomes. Circ_0074269 facilitated DDP resistance via elevating TUFT1 expression via sponging miR-485-5p, proving novel evidence to offer circ_0074269 as a target for cervical cancer treatment.

Inhibition of RAC1 activity in cancer associated fibroblasts favours breast tumour development through IL-1β upregulation

Cancer-associated fibroblasts (CAFs) are highly abundant stromal components in the tumour microenvironment. These cells contribute to tumorigenesis and indeed, they have been proposed as a target for anti-cancer therapies. Similarly, targeting the Rho-GTPase RAC1 has also been suggested as a potential therapeutic target in cancer. Here, we show that targeting RAC1 activity, either pharmacologically or by genetic silencing, increases the pro-tumorigenic activity of CAFs by upregulating IL-1β secretion. Moreover, inhibiting RAC1 activity shifts the CAF subtype to a more aggressive phenotype. Thus, as RAC1 suppresses the secretion of IL-1β by CAFs, reducing RAC1 activity in combination with the depletion of this cytokine should be considered as an interesting therapeutic option for breast cancer in which tumour cells retain intact IL-1β signalling.

Tuftelin 1 (TUFT1) Promotes the Proliferation and Migration of Renal Cell Carcinoma via PI3K/AKT Signaling Pathway

Tuftelin 1 (TUFT1), a protein functioning distinctively in different tissues, is reported to be elevated in several types of cancers and the elevation of TUFT1 is correlated with unfavorable clinicopathologic characteristics and poor survival. However, the involvement of TUFT1 in renal cell carcinoma (RCC) remains unknown. In the current study, we investigated the role of TUFT1 in RCC and potential underlying mechanisms. RT-PCR and Western blot analysis showed that both the mRNA and protein levels of TUFT1 were increased in primary RCC tissue and RCC cell lines. TUFT1 overexpression in RCC cells resulted in enhanced cell proliferation and migration while knockdown of TUFT1 by contrast decreased the growth and migration of the RCC cells, indicating TUFT1 expression is involved in RCC cell growth and migration. The involvement of TUFT1 in the epithelial-mesenchymal transition (EMT) of RCC cells was also determined by measuring the expression of EMT-related markers. Our data showed that TUFT1 overexpression promoted RCC cell EMT progression while knockdown of TUFT1 suppressed such process. Further signaling pathway inhibition assay revealed that TUFT1-induced RCC cell growth, migration and EMT was significantly suppressed by PI3K inhibitor, but not JNK or MEK inhibitors. In addition, TUFT1 overexpression enhanced the AKT phosphorylation, a key member of the PI3K signaling pathway, while PI3K inhibitor suppressed such process. Taken together, our study showed that TUFT1 expression was elevated in RCC and such elevation promoted the proliferation, migration and EMT of RCC cells in vitro, through PI3K/AKT signaling pathway. The findings of our current study imply that TUFT1 is involved in RCC tumorigenesis, and it may serve as a biomarker for RCC diagnosis and a potential target for RCC treatment.

Knockdown of circ_0006528 Suppresses Cell Proliferation, Migration, Invasion, and Adriamycin Chemoresistance via Regulating the miR-1236-3p/CHD4 Axis in Breast Cancer

BACKGROUND

Adriamycin (ADM) is one of the postoperative chemotherapy drugs for breast cancer (BCa) patients. Circular RNAs have been shown to modulate ADM resistance in many cancers. However, it is unclear whether circ_0006528 can modulate the ADM chemoresistance in BCa.

METHODS

Levels of circ_0006528, microRNA-1236-3p (miR-1236-3p), and chromodomain helicase DNA-binding protein 4 (CHD4) were detected by quantitative real-time polymerase chain reaction or western blot. Cell proliferation, the half maximal inhibitory concentration (IC50) value of ADM, and cell migration and invasion were evaluated by cell counting kit-8 and transwell assays, respectively. The interaction among circ_0006528, miR-1236-3p, and CHD4 was confirmed using dual-luciferase reporter assays. Tumor formation in nude mice was performed to explore the effect of circ_0006528 in vivo.

RESULTS

Higher levels of circ_0006528 and CHD4 and lower level of miR-1236-3p were found in ADM-resistant BCa tissues and cells, and patients with high circ_0006528 had a shorter overall survival. Circ_0006528 could directly bind to miR-1236-3p, and circ_0006528 knockdown or miR-1236-3p overexpression could suppress cell proliferation, migration, invasion, and ADM resistance in ADM-resistant BCa cells. Moreover, circ_0006528-regulated CHD4 expression by sponging miR-1236-3p, and CHD4 elevation reversed the inhibitory effect of circ_0006528 knockdown on ADM-resistant BCa cells. Consistently, circ_0006528 inhibition retarded ADM-resistant BCa tumor growth in vivo by decreasing CHD4 and increasing miR-1236-3p.

CONCLUSIONS

Downregulation of circ_0006528 restrained cell proliferation, migration, invasion, and drug resistance of ADM-resistant BCa cells through inhibiting CHD4 and inducing miR-1236-3p.

A Risk Score System Based on the Methylation Levels of 15 RNAs in Breast Cancer

Background: Breast cancer (BC) occurs in the epithelial tissues of the breast gland, which is the most common cancer in women. This study is implemented to construct a risk score system for BC. Methods: The methylation data of BC from The Cancer Genome Atlas database (the training set) and GSE37754 from Gene Expression Omnibus database (the validation set) were downloaded. The differentially methylated RNAs (DMRs) between BC and normal samples were screened by limma package, and the correlations between the expression levels and methylation levels of the DMRs were analyzed to calculate their Pearson correlation coefficients (PCCs) using the cor.test function. To build the risk score system, the optimal RNAs were identified by penalized package. Subsequently, the nomogram survival model was established using the rms package. The lncRNA-mRNA comethylation network was constructed by Cytoscape software, and then enrichment analysis was performed using DAVID tool. Results: From the 1170 DMRs between BC and normal samples, 800 DMRs with significant negative PCCs were screened. For building the risk score system, the 15 optimal RNAs were selected. Afterward, the nomogram survival model based on four independent clinical prognostic factors (including age, radiation therapy, tumor recurrence, and RS model status) was constructed. In the comethylation network, the long noncoding RNA (lncRNA) PRNT was comethylated with FAM19A5 and RBM24. For the mRNAs in the comethylation network, angiogenesis and pathways in cancer were enriched. Conclusion: The risk score system and the nomogram survival model might be of great importance for the prognosis prediction of BC patients.

LncRNA DANCR upregulation induced by TUFT1 promotes malignant progression in triple negative breast cancer via miR-874-3p-SOX2 axis

Triple negative breast cancer (TNBC) is a subtype of breast cancer with poorest survival outcome and is prone to metastasis. TUFT1 and the long non-coding RNA (lncRNA), DANCR, play vital roles in metastasis and progression of various cancers. However, the correlation between TUFT1 and DANCR in TNBC and their downstream molecular mechanisms are still undetermined. We demonstrated that upregulation of TUFT1 in TNBC was related to a worse survival in TNBC patients. The TNBC cells invasiveness was augmented by TUFT1 in a dose-dependent manner, while inhibiting TUFT1 repressed the invasiveness. Particularly, the expression of TUFT1 was positively correlated with the expression of DANCR in TNBC tissues. In addition, TUFT1 increased DANCR expression, while silencing DANCR ameliorated the invasiveness of TNBC cells induced by TUFT1. As demonstrated, TUFT1 interacted with miR-874-3p. Subsequently, qRT-PCR together with luciferase reporter further demonstrated that DANCR acted as competing endogenous (ceRNA) for miR-874-3p, thereby regulating the de-repression of SOX2 and advancing epithelial-mesenchymal transition (EMT) in TNBC. The present research shows that TUFT1 promotes the malignant development in TNBC via enhancing the expression of DANCR. The upregulation of DANCR may contribute to the progression and tumor invasiveness of TNBC, considering that DANCR functions as a miR-874-3p sponge, thus modulating SOX2 positively. Collectively, the present study explored the molecular mechanism underlying TUFT1 in TNBC, raising a TUFT1-mediated therapy for the treatment of patients with TNBC.

Evaluation of active Rac1 levels in cancer cells: A case of misleading conclusions from immunofluorescence analysis

A large number of aggressive cancer cell lines display elevated levels of activated Rac1, a small GTPase widely implicated in cytoskeleton reorganization, cell motility, and metastatic dissemination. A commonly accepted methodological approach for detecting Rac1 activation in cancer cells involves the use of a conformation-sensitive antibody that detects the active (GTP-bound) Rac1 without interacting with the GDP-bound inactive form. This antibody has been extensively used in fixed cell immunofluorescence and immunohistochemistry. Taking advantage of prostate and pancreatic cancer cell models known to have high basal Rac1-GTP levels, here we have established that this antibody does not recognize Rac1 but rather detects the intermediate filament protein vimentin. Indeed, Rac1-null PC3 prostate cancer cells or cancer models with low levels of Rac1 activation still show a high signal with the anti-Rac1-GTP antibody, which is lost upon silencing of vimentin expression. Moreover, this antibody was unable to detect activated Rac1 in membrane ruffles induced by epidermal growth factor stimulation. These results have profound implications for the study of this key GTPase in cancer, particularly because a large number of cancer cell lines with characteristic mesenchymal features show simultaneous up-regulation of vimentin and high basal Rac1-GTP levels when measured biochemically. This misleading correlation can lead to assumptions about the validity of this antibody and inaccurate conclusions that may affect the development of appropriate therapeutic approaches for targeting the Rac1 pathway.