TOB1 modulates neutrophil phenotypes to influence gastric cancer progression and immunotherapy efficacy

Introduction

The ErbB-2.1(TOB1) signaling transducer protein is a tumor-suppressive protein that actively suppresses the malignant phenotype of gastric cancer cells. Yet, TOB1 negatively regulates the activation and growth of different immune cells. Understanding the expression and role of TOB1 in the gastric cancer immune environment is crucial to maximize its potential in targeted immunotherapy.

Methods

This study employed multiplex immunofluorescence analysis to precisely delineate and quantify the expression of TOB1 in immune cells within gastric cancer tissue microarrays. Univariate and multivariate Cox analyses were performed to assess the influence of clinical-pathological parameters, immune cells, TOB1, and double-positive cells on the prognosis of gastric cancer patients. Subsequent experiments included co-culture assays of si-TOB1-transfected neutrophils with AGS or HGC-27 cells, along with EdU, invasion, migration assays, and bioinformatics analyses, aimed at elucidating the mechanisms through which TOB1 in neutrophils impacts the prognosis of gastric cancer patients.

Results

We remarkably revealed that TOB1 exhibits varying expression levels in both the nucleus (nTOB1) and cytoplasm (cTOB1) of diverse immune cell populations, including CD8+ T cells, CD66b+ neutrophils, FOXP3+ Tregs, CD20+ B cells, CD4+ T cells, and CD68+ macrophages within gastric cancer and paracancerous tissues. Significantly, TOB1 was notably concentrated in CD66b+ neutrophils. Survival analysis showed that a higher density of cTOB1/nTOB1+CD66b+ neutrophils was linked to a better prognosis. Subsequent experiments revealed that, following stimulation with the supernatant of tumor tissue culture, the levels of TOB1 protein and mRNA in neutrophils decreased, accompanied by enhanced apoptosis. HL-60 cells were successfully induced to neutrophil-like cells by DMSO. Neutrophils-like cells with attenuated TOB1 gene expression by si-TOB1 demonstrated heightened apoptosis, consequently fostering a malignant phenotype in AGS and HCG-27 cells upon co-cultivation. The subsequent analysis of the datasets from TCGA and TIMER2 revealed that patients with high levels of TOB1 combined neutrophils showed better immunotherapy response.

Discussion

This study significantly advances our comprehension of TOB1's role within the immune microenvironment of gastric cancer, offering promising therapeutic targets for immunotherapy in this context.

Functional mechanism of miR-92b-3p in osteogenic differentiation of fibroblasts in patients with ankylosing spondylitis via the TOB1/BMP/Smad pathway

BACKGROUND

Ankylosing spondylitis (AS) is a chronic inflammatory arthritis. Upregulation of microRNA (miR)-92b-3p is associated with enhanced osteoblastic differentiation. The current study sought to investigate the functional mechanism of miR-92b-3p in osteogenic differentiation of AS fibroblasts.

METHODS

First, fibroblasts were isolated from AS and non-AS patients and cultured. Next, cell morphology was observed, cell proliferation was assessed and the vimentin expression pattern was determined. Alkaline phosphatase (ALP) activity and levels of osteogenic markers RUNX2, OPN, OSX, and COL I were additionally measured, followed by determination of miR-92b-3p and TOB1 levels. The binding site of miR-92b-3p and TOB1 was predicted, and their target relationship was validated. Lastly, miR-92b-3p inhibitor, si-TOB1, and the BMP/Smad signaling pathway inhibitor LDN193189 were delivered into AS fibroblasts to evaluate the osteogenic differentiation of AS fibroblasts and the activation of the BMP/Smad pathway.

RESULTS

miR-92b-3p was highly expressed in AS fibroblasts. AS fibroblasts showed enhanced osteogenic differentiation and proliferation, while inhibition of miR-92b-3p suppressed osteogenic differentiation and proliferation of AS fibroblasts. miR-92b-3p targeted TOB1, and TOB1 was poorly expressed in AS fibroblasts. The concurrent downregulation of TOB1 and inhibition of miR-92b-3p elevated the levels of RUNX2, OPN, OSX, and COL I and ALP activity and further enhanced the proliferation of AS fibroblasts. The BMP/Smad pathway was activated in AS fibroblasts. Silencing miR-92b-3p could inhibit the activation of the BMP/Smad pathway by upregulating TOB1. Inhibition of the BMP/Smad pathway reduced the number of calcified nodules and hindered the osteogenic differentiation and proliferation of AS fibroblasts.

CONCLUSION

Our findings highlighted that silencing miR-92b-3p inhibited the osteogenic differentiation and proliferation of AS fibroblasts by upregulation of TOB1 and inhibition of the BMP/Smad pathway.

Methylation Mediated Downregulation of TOB1-AS1 and TOB1 Correlates with Malignant Progression and Poor Prognosis of Esophageal Squamous Cell Carcinoma

BACKGROUND

TOB1, a member of the transducer of erbB-2 /B-cell translocation gene family, was detected to be down-regulated in ESCC by RNA sequencing. TOB1-AS1, a head-to-head antisense lncRNA with TOB1, was down-regulated in several cancers. However, the roles of them in esophageal squamous cell carcinoma (ESCC) remained unclarified.

AIMS

To investigate the roles and functions of TOB1-AS1 and TOB1 in ESCC tumorigenesis.

MATERIALS AND METHODS

The expression levels, methylation status, biological function and mechanisms of TOB1-AS1 and TOB1 in ESCC were, respectively, detected.

RESULTS

Frequent down-regulation of TOB1-AS1 and TOB1 was verified in esophageal cancer cells and ESCC tissues, and there was a positive correlation between them in ESCC tissues. The CpG sites hypermethylation within proximal promoter of TOB1-AS1 and TOB1 could lead to transcriptional inhibition of both genes. Furthermore, expression and proximal promoter methylation status of TOB1-AS1 or TOB1 may be associated with ESCC patients' prognosis. TOB1-AS1 and TOB1 may function as tumor suppressors by inhibiting growth, migration, and invasion of esophageal cancer cells. Up-regulation of TOB1-AS1 increased expression level of TOB1, and TOB1-AS1 could work as a ceRNA to modulate ATF3 expression via competitively binding with miR-103a-2-5p. Meanwhile, ATF3, as a transcription factor, could regulate transcription of TOB1; down-regulation of TOB1-AS1 in ESCC led to decreased expression of ATF3 through ceRNA mechanism, and further influenced the transcription of TOB1.

CONCLUSION

TOB1-AS1 and TOB1 may act as tumor suppressors and may serve as potential targets for antitumor therapy in ESCC.

TOB1 Blocks Intestinal Mucosal Inflammation Through Inducing ID2-Mediated Suppression of Th1/Th17 Cell Immune Responses in IBD

BACKGROUND & AIMS

TOB1 is an anti-proliferative protein of Tob/BTG family and typically involved in the tumorigenesis and T cell activation. Although TOB1 is associated with T helper 17 cell-related autoimmunity, its role in modulating T cell-mediated immune responses in IBD remains poorly understood. Here, we explored its expression and the underlying mechanisms involved in the pathogenesis of inflammatory bowel disease (IBD).

METHODS

TOB1 and ID2 expression in IBD patients was examined by quantitative real time polymerase chain reaction and immunohistochemistry. IBD CD4⁺ T cells were transfected with lentivirus expressing TOB1, ID2, TOB1 short hairpin RNA and ID2 short hairpin RNA, respectively, and Tob1^-/-CD4⁺ T cells were transfected with lentivirus expressing Id2. Experimental colitis was established in Tob1^-/- mice by trinitrobenzene sulfonic acid enema and in Rag1^-/- mice reconstituted with Tob1^-/-CD45RB^highCD4⁺ T cells to further explore the role of Tob1 in intestinal mucosal inflammation. Splenic CD4⁺ T cells of Tob1^-/- mice were sorted to determine transcriptome differences by RNA sequencing.

RESULTS

TOB1 expression was decreased in inflamed mucosa and peripheral blood CD4⁺ T cells of IBD patients compared with healthy subjects. Overexpression of TOB1 downregulated IBD CD4⁺ T cells to differentiate into Th1/Th17 cells compared with control subjects. Severe colitis was observed in Tob1^-/- mice through trinitrobenzene sulfonic acid enema or in Rag1^-/- mice reconstituted with Tob1^-/-CD45RB^highCD4⁺ T cells, compared with control animals. RNA sequencing analysis revealed ID2 as functional target of TOB1 to inhibit IBD CD4⁺ T cell differentiation into Th1/Th17 cells. Mechanistically, TOB1 was associated with Smad4/5 to induce ID2 expression and restrain Th1/Th17 cell differentiation.

CONCLUSIONS

TOB1 restrains intestinal mucosal inflammation through suppressing Th1/Th17 cell-mediated immune responses via the Smad4/5-ID2 pathway. It may serve as a novel therapeutic target for treatment of human IBD.

LncRNA NR2F1-AS1 Regulates miR-371a-3p/TOB1 Axis to Suppress Proliferation of Colorectal Cancer Cells

A recent study reported the oncogenic function of lncRNA NR2F1-AS1 in liver cancer. Interestingly, by analyzing TCGA data set, downregulation of NR2F1-AS1 in colorectal cancer (CRC) was observed. This observation triggered interest to analyze the functions of NR2F1-AS1 in CRC. It was observed that NR2F1-AS1 was downregulated in CRC and predicted poor survival. NR2F1-AS1 can directly interact with miR-371a-3p but their overexpression failed to affect the expression of each other. However, NR2F1-AS1 overexpression led to the upregulation of TOB1, a target of miR-371a-3p. Cell proliferation analysis revealed reduced proliferation rate of CRC cells after NR2F1-AS1 and TOB1 overexpression. MiR-371a-3p overexpression played an opposite role and reduced the effects of NR2F1-AS1 and TOB1 overexpression. In conclusion, NR2F1-AS1 regulates miR-371a-3p/TOB1 axis to suppress proliferation of CRC cells.

LncRNA WEE2-AS1 promotes proliferation and inhibits apoptosis in triple negative breast cancer cells via regulating miR-32-5p/TOB1 axis

Triple negative breast cancer (TNBC) is a malignant breast cancer subtype with poor prognosis. Recent studies have revealed the critical roles of dysregulated long non-coding RNAs (lncRNAs) in many cancer types, including TNBC. LncRNA WEE2 antisense RNA 1 (WEE2-AS1) has been reported to be able to promote the progression of hepatocellular carcinoma, but the function of WEE2-AS1 in TNBC is still unknown. Therefore, in this study, we specifically researched the role of WEE2-AS1 and probed its molecular mechanism in TNBC cells. Our results showed that WEE2-AS1 was up-regulated in TNBC cell lines, and WEE2-AS1 knockdown could inhibit TNBC cell proliferation, promote apoptosis, and suppress migration and invasion. Further, we found that miR-32-5p was down-regulated in TNBC cells and could be sponged by WEE2-AS1. Moreover, miR-32-5p could target its downstream gene transducer of ERBB2, 1 (TOB1), which was highly expressed and could play the oncogenic role in TNBC cells. Through rescue assays, we proved that WEE2-AS1/miR-32-5p/TOB1 axis could modulate cancer progression in TNBC cells. In conclusion, our results demonstrated the oncogenic function of lncRNA WEE2-AS1 in TNBC cells, providing a novel insight into TNBC therapy.

TOB1 suppresses proliferation in K-Ras wild-type pancreatic cancer

TOB1 participates in various kinds of cancers. However, its role in pancreatic cancer has rarely been reported. In this study, we explored the expression and mechanisms of TOB1 in regulating the malignant phenotype of pancreatic cancer cells. TOB1 expression was determined by data mining and immunohistochemistry (IHC), and its localization was observed by immunofluorescence. CCK‐8 cell proliferation, colony formation, flow cytometric, transwell migration, and Western blot (WB) assays were used to examine how it impacts the malignant phenotype of pancreatic cancer. Furthermore, Foxa2 binding to TOB1 was tested by dual‐luciferase reporter assays, and RNA‐Seq was performed to identify signaling pathways. We found TOB1 was downregulated in pancreatic cancer tissues and was mainly located in the cytoplasm. TOB1 overexpression reduced the proliferation of K‐Ras wild‐type pancreatic cancer cells but made no difference to cell migration and invasion. Foxa2 overexpression significantly enhanced TOB1 promoter activity. Moreover, overexpressing TOB1 substantially enriched the calcium pathway in K‐Ras wild‐type pancreatic cancer cells. In conclusion, TOB1 may suppress the proliferation of K‐Ras wild‐type pancreatic cancer cells by regulating calcium pathway genes.

MiR-32-5p Regulates Radiosensitization, Migration And Invasion Of Colorectal Cancer Cells By Targeting TOB1 Gene

Background

MicroRNAs (miRNAs) play key roles in the development and progression of various cancers. However, the precise functions and regulation mechanisms of miRNAs in human tumors remain elusive.

Methods

Quantitative real time-PCR (qRT-PCR) was performed to detect the level of miR-32-5p in colorectal cancer tissues. The relationships between miR-32-5p level with clinicopathological characteristics and prognosis were analyzed. The miR-32-5p inhibitor was employed to knock down the expression of miR-32-5p. The overexpression plasmid and si-RNA targeting TOB1 were generated. Clone formation assays under radiant exposure were used to evaluate the radiosensitization. Transwell migration and invasion were employed to test the ability of cell migration and invasion. Luciferase reporter assays were used to confirm the regulation of miR-32-5p on the expression of TOB1. Rescue experiments were conducted to investigate the effects of TOB1 on the functions of miR-32-5p.

Results

In this study, we found that miR-32-5p was significantly upregulated in colorectal cancer tissues compared with adjacent normal tissues. The level of miR-32-5p was positively correlated with tumor differentiation and metastasis. Log-rank tests showed that high level of miR-32-5p was significantly correlated with poor overall survival and disease-free survival. Anti-miR-32-5p remarkably enhanced the radiosensitivity and inhibited migration and invasion of colorectal cancer cells. In addition, overexpression of TOB1 obviously increased the radiosensitivity and inhibited migration and invasion of colorectal cancer cells. Moreover, bioinformatics analysis and luciferase reporter assays demonstrated that miR-32-5p suppressed the expression of TOB1 through directly binding to the 3ʹ-UTR of TOB1 mRNA. Rescue experiments indicated that miR-32-5p regulated the radiosensitivity, migration and invasion of colorectal cancer cells through inhibiting TOB1 expression.

Conclusion

This study suggested that miR-32-5p may serve as a prognostic and therapeutic target for colorectal cancer, and downregulation of miR-32-5p enhanced the radiosensitivity and inhibited migration and invasion through promoting TOB1 expression.

Phosphorylation of TOB1 at T172 and S320 is critical for gastric cancer proliferation and progression

We previously revealed that increased phosphorylation of TOB1, a tumor suppressor protein, may promote the progression of gastric cancer. However, the phosphorylated sites on TOB1 and their functional implication in gastric cancer remain to be clarified. Here, we addressed these questions using the gastric mucosal epithelial cell line GES-1 and three gastric cancer cell lines (HGC-27, AGS, and MKN-1). Compared with the control GES-1 cells, the gastric cancer cells showed decreased levels of TOB1 protein and increased levels of phosphorylated TOB1 (p-TOB1) by Western blotting. Then, TOB1 protein was enriched and purified by immunoprecipitation. Two novel phosphorylation sites at threonine 172 (T172) and serine 320 (S320) in TOB1 were identified in gastric cancer MKN-1 cells using LC-MS/MS. Furthermore, treatment with the serine/threonine kinase inhibitor staurosporine (STS; 2 nmol/L, 8 h) significantly decreased the levels of p-TOB1. As a result, the proliferation, migration, and invasion of gastric cancer cells were diminished, accompanied by an increased proportion of cells in G1 phase and a decreased proportion of cells in G2 phase. Taken together, these findings indicate for the first time that TOB1 is phosphorylated at T172 and S320 in gastric cancer cells, which are sensitive to STS. Downregulation of p-TOB1 levels by STS treatment can weaken the malignant phenotype of gastric cancer cells and block their progression through the cell cycle. Moreover, STS may exert its antiproliferative activity in gastric cancers by restoring TOB1 protein activity.

Genome-Wide Interaction and Pathway Association Studies for Body Mass Index

Objective: We investigated gene interactions (epistasis) for body mass index (BMI) in a European-American adult female cohort via genome-wide interaction analyses (GWIA) and pathway association analyses. Methods: Genome-wide pairwise interaction analyses were carried out for BMI in 493 extremely obese cases (BMI > 35 kg/m2) and 537 never-overweight controls (BMI < 25 kg/m2). To further validate the results, specific SNPs were selected based on the GWIA results for haplotype-based association studies. Pathway-based association analyses were performed using a modified Gene Set Enrichment Algorithm (GSEA) (GenGen program) to further explore BMI-related pathways using our genome wide association study (GWAS) data set, GIANT, ENGAGE, and DIAGRAM Consortia. Results: The EXOC4-1q23.1 interaction was associated with BMI, with the most significant epistasis between rs7800006 and rs10797020 (P = 2.63 × 10-11). In the pathway-based association analysis, Tob1 pathway showed the most significant association with BMI (empirical P < 0.001, FDR = 0.044, FWER = 0.040). These findings were further validated in different populations. Conclusion: Genome-wide pairwise SNP-SNP interaction and pathway analyses suggest that EXOC4 and TOB1-related pathways may contribute to the development of obesity.

Decreased expression levels of DAL-1 and TOB1 are associated with clinicopathological features and poor prognosis in gastric cancer

PURPOSE

We previously demonstrated that the functional inactivation of DAL-1 and TOB1 promotes an aggressive phenotype in gastric cancer cells, but the links between both genes and the survival of patients with gastric cancer are unknown. Here, we investigated the correlations of the expression levels of DAL-1 and TOB1 with the progression of gastric cancer.

METHODS

A total of 270 patients who underwent resectable gastrectomy were included. The expression of DAL-1 and TOB1 was detected by immunohistochemistry.

RESULTS

Low expression of DAL-1 in cancer tissue was significantly associated with tumor site (p < 0.05), histological grade (p < 0.01), depth of invasion (p < 0.05), lymph node metastasis status (p < 0.05), Lauren classification (p < 0.001), and clinical stage (p < 0.01). A lower level of TOB1 was observed in gastric cancer patients with diffuse type disease compared to patients with either intestinal or mixed type disease (p < 0.001). Additionally, Spearman's correlation analysis revealed that decreased expression of DAL-1 was positively correlated with low TOB1 expression (r=0.304, p < 0.001). The survival analysis showed that low levels of DAL-1 and TOB1 were significantly associated with poor survival of gastric cancer patients (p <0.001 and p < 0.05, respectively).

CONCLUSION

The downregulation of DAL-1 and TOB1 expression is associated with shorter survival of gastric cancer patients. Hence, DAL-1 and TOB1 may be considered potential novel markers for predicting the outcomes of patients with gastric cancer.

Increased expression of Tbet in CD4(+) T cells from clinically isolated syndrome patients at high risk of conversion to clinically definite MS

Background

The ability to identify clinically isolated syndrome (CIS) patients at high risk of progression to clinically definite multiple sclerosis (CDMS) would be clinically beneficial. The initiation of T cell mediated autoimmune diseases such as multiple sclerosis (MS) requires the initial inappropriate activation and differentiation of auto-reactive CD4⁺ T cells. The quiescence of naive T cells is actively maintained by molecules such as TOB1, which control the threshold of activation. Upon activation, CD4⁺ T cells can differentiate into various subsets depending on the milieu present. Th1 and Th17 cells are strongly implicated in MS, while regulatory T (Treg) cells constrain autoimmune inflammation and prevent autoimmunity.

Findings

We therefore investigated the expression of TOB1, CD44 and Treg, Th1 and Th17 transcription factors in relation to CIS progression. The expression of TOB1, CD44, FOXP3, TBX21 and RORC genes were measured in CD4⁺ T cells from 10 healthy controls, 20 CIS patients within 3 months of initial clinical presentation and 10 relapsing remitting MS patients sampled within 2 months of relapse. CIS patients were subsequently grouped into those who converted to CDMS within 1 year and those who remained CIS. No differences in the expression of TOB1, CD44, FOXP3 and RORC were observed. There was a significant increase in the expression of the Th1 transcription factor Tbet, encoded by TBX21, in CIS patients that converted within 1 year compared with those who did not.

Conclusion

This pilot data suggests a role for Th1 cells in CIS progression and warrants further evaluation in a larger cohort.

Better safe than sorry: TOB1 employs multiple parallel regulatory pathways to keep Th17 cells quiet

Th17 cells are key players in antibacterial and antifungal immunity, but have also been implicated in autoimmunity. Interestingly, Th17 cells poorly proliferate upon stimulation, a phenotype that was attributed to a decreased sensitivity to T-cell receptor (TCR) stimulation, and to low IL-2 production by Th17 cells. In this issue of the European Journal of Immunology, Santarlasci et al. [Eur. J. Immunol. 2014. 44: 654-661] shed further light on the molecular mechanism that keeps Th17 cells at bay. They identify the transcriptional regulator TOB1, which not only impairs IL-2 production in Th17 cells, but also blocks the expression of cell cycle genes. Strikingly, TOB1 suppresses Th17-cell proliferation through several pathways, including impaired signal transduction, transcription, and possibly also post-transcriptional regulation.