Protective effects of intestinal trefoil factor (ITF) on gastric mucosal epithelium through activation of extracellular signal-regulated kinase 1/2 (ERK1/2). Mol Cell Biochem. 2015;404:263-270. [PMID: 25776570 DOI: 10.1007/s11010-015-2386-2]

Pretreatment with intestinal trefoil factor alleviates stress-induced gastric mucosal damage via Akt signaling

BACKGROUND

Stress-related gastric mucosal damage or ulcer remains an unsolved issue for critically ill patients. Stress ulcer prophylaxis has been part of routine intensive care, but uncertainty and controversy still exist. Co-secreted with mucins, intestinal trefoil factor (ITF) is reported to promote restitution and regeneration of intestinal mucosal epithelium, although the mechanism remains unknown.

AIM

To elucidate the protective effects of ITF on gastric mucosa and explore the possible mechanisms.

METHODS

We used a rat model of gastric mucosal damage induced by water immersion restraint stress and lipopolysaccharide-treated human gastric epithelial cell line to investigate the potential effects of ITF on damaged gastric mucosa both in vivo and in vitro.

RESULTS

ITF promoted the proliferation and migration and inhibited necrosis of gastric mucosal epithelia in vitro. It also preserved the integrity of gastric mucosa by upregulating expressions of occludin and zonula occludens-1. In the rat model, pretreatment with ITF ameliorated the gastric mucosal epithelial damage and facilitated mucosal repair. The protective effects of ITF were confirmed to be exerted via activation of Akt signaling, and the specific inhibitor of Akt signaling LY249002 reversed the protective effects.

CONCLUSION

ITF might be a promising candidate for prevention and treatment of stress-induced gastric mucosal damage, and further studies should be undertaken to verify its clinical feasibility.

Structure, Function, and Therapeutic Potential of the Trefoil Factor Family in the Gastrointestinal Tract

Trefoil factor family peptides (TFF1, TFF2, and TFF3) are key players in protecting, maintaining, and repairing the gastrointestinal tract. Accordingly, they have the therapeutic potential to treat and prevent a variety of gastrointestinal disorders associated with mucosal damage. TFF peptides share a conserved motif, including three disulfide bonds that stabilize a well-defined three-loop-structure reminiscent of a trefoil. Although multiple functions have been described for TFF peptides, their mechanisms at the molecular level remain poorly understood. This review presents the status quo of TFF research relating to gastrointestinal disorders. Putative TFF receptors and protein partners are described and critically evaluated. The therapeutic potential of these peptides in gastrointestinal disorders where altered mucosal biology plays a crucial role in the underlying etiology is discussed. Finally, areas of investigation that require further research are addressed. Thus, this review provides a comprehensive update on TFF literature as well as guidance toward future research to better understand this peptide family and its therapeutic potential for the treatment of gastrointestinal disorders.

TFF3 and TFF1 expression levels are elevated in colorectal cancer and promote the malignant behavior of colon cancer by activating the EMT process

Reports on the roles of the secreted trefoil factor (TFF)1 and 3 in colorectal cancer (CRC) and their underlying mechanisms of action in tumorigenesis are not common and are controversial. In the present study, the mRNA expression and promoter methylation of TFF1 and TFF3 in cancer and adjacent normal tissues were investigated, and their association with other clinical factors and patient prognosis were evaluated. Moreover, the association between TFF3 and epithelial mesenchymal transition (EMT) was explored by overexpressing or inhibiting TFF3 expression. The results revealed that the mRNA level of TFF1 and TFF3 in the cancer tissues was significantly higher than that in the matched adjacent normal tissues (P=0.034 and P=0.007, respectively), and a higher expression of TFF3, but not TFF1, was predominantly associated with clinicopathological factors and a poorer prognosis. No correlation was observed between promoter methylation and the expression of TFF1 or TFF3. The overexpression of TFF3 promoted the proliferation, migration and invasiveness of HT29 cells, and induced an increase in the expression of Twist1, Snail and Vimentin, while causing a decrease in E-cadherin expression. On the contrary, the knockdown of TFF3 resulted in opposite effects in the LoVo cells. On the whole, the findings of this study indicate that TFF3 may be a promising new factor for the estimation of the survival of patients with CRC, and may promote the malignant progression of CRC by activating the EMT process. Therefore, TFF3 may be a future potential therapeutic target for CRC.

TFF3 Contributes to Epithelial-Mesenchymal Transition (EMT) in Papillary Thyroid Carcinoma Cells via the MAPK/ERK Signaling Pathway

Trefoil factor 3 (TFF3) was found to be overexpressed in many types of tumours. Evidence has shown that TFF3 plays an important role in tumour proliferation, migration and invasion metastasis. However, the impact of TFF3 on patients' clinicopathological characteristics and underlying mechanisms remain unknown in papillary thyroid carcinoma (PTC). In this study, the expression of TFF3 and the epithelial-mesenchymal transition (EMT) transcriptional factor Snail in PTC and para-carcinoma specimens was evaluated by immunohistochemistry (IHC) and Western blot, and the possible associations with lymph node (LN) metastasis and other clinicopathological parameters were analysed. In vitro, the effect of TFF3 on the malignant behaviour of TPC-1 cells was evaluated by cell proliferation assays, cell adhesion assays, colony formation assays, wound-healing assays and transwell chamber invasion assays. EMT markers and regulatory molecules were detected by quantitative RT-PCR (qRT-PCR) and Western blot analysis in the TFF3-knockdown groups and shRNA control group. The results showed that TFF3 was upregulated in PTC tissue and was associated with lymph node metastasis (P=0.0001), pathological grade (P=0.0002) and Snail expression (P=0.0001). The knockdown of TFF3 markedly inhibited the abilities of TPC-1 cell proliferation, adhesion, colony formation, migration and invasion. Mechanically, the results demonstrated that TFF3 might activate the MAPK/ERK signalling pathways, affect the expression of the transcription factors snail and slug in addition to affecting EMT associated markers E-cadherin and N-cadherin, and accelerate the progression of EMT in TPC-1 cells. These findings indicate that TFF3 might promote the metastatic potential of PTC by promoting the EMT process through cascades of MAPK/ERK pathways.

Localization of trefoil factor family peptide 3 (TFF3) in epithelial tissues originating from the three germ layers of developing mouse embryo

Trefoil factor family (TFF) peptides are involved in the maintenance of epithelial integrity and epithelial restitution. Mature epithelial tissues originate from different embryonic germ layers. The objective of this research was to explore the presence and localization of TFF3 peptide in mouse embryonic epithelia and to examine if the occurrence of TFF3 peptide is germ layer-dependent. Mouse embryos (14-18 days old) were fixed in 4% paraformaldehyde and embedded in paraffin. Immunohistochemistry was performed with affinity purified rabbit anti-TFF3 antibody, goat anti-rabbit biotinylated secondary antibody and streptavidin-horseradish peroxidase, followed by 3,3'-diaminobenzidine. TFF3 peptide was present in the gastric and intestinal mucosa, respiratory mucosa in the upper and lower airways, pancreas, kidney tubules, epidermis, and oral cavity. The presence and localization of TFF3 peptide was associated with the embryonic stage and tissue differentiation. TFF3 peptide distribution specific to the germ layers was not observed. The role of TFF3 peptide in cell migration and differentiation, immune response, and apoptosis might be associated with specific embryonic epithelial cells. TFF3 peptide may also be considered as a marker for mucosal maturation.

Release of HER2 repression of trefoil factor 3 (TFF3) expression mediates trastuzumab resistance in HER2+/ER+ mammary carcinoma

HER2+/ER+ breast cancer, a subset of the luminal B subtype, makes up approximately 10% of all breast cancers. The bidirectional crosstalk between HER2 and estrogen receptor (ER) in HER2+/ER+ breast cancer contributes to resistance towards both anti-estrogens and HER2-targeted therapies. TFF3 promotes breast cancer progression and has been implicated in anti-estrogen resistance in breast cancer. Herein, we investigated the cross-regulation between HER2 and estrogen-responsive TFF3, and the role of TFF3 in mediating trastuzumab resistance in HER2+/ER+ breast cancer. TFF3 expression was decreased by HER2 activation, and increased by inhibition of HER2 with trastuzumab in HER2+/ER+ breast cancer cells, partially in an ERα-independent manner. In contrast, the forced expression of TFF3 activated the entire HER family of receptor tyrosine kinases (HER1-4). Hence, HER2 negatively regulates its own signalling through the transcriptional repression of TFF3, while trastuzumab inhibition of HER2 results in increased TFF3 expression to compensate for the loss of HER2 signalling. In HER2+/ER+ breast cancer cells with acquired trastuzumab resistance, TFF3 expression was markedly upregulated and associated with a corresponding decrease in HER signalling. siRNA mediated depletion or small molecule inhibition of TFF3 decreased the survival and growth advantage of the trastuzumab resistant cells without re-sensitization to trastuzumab. Furthermore, TFF3 inhibition abrogated the enhanced cancer stem cell-like behaviour in trastuzumab resistant HER2+/ER+ breast cancer cells. Collectively, TFF3 may function as a potential biomarker and therapeutic target in trastuzumab resistant HER2+/ER+ breast cancer.

Forced Trefoil Factor Family Peptide 3 (TFF3) Expression Reduces Growth, Viability, and Tumorigenicity of Human Retinoblastoma Cell Lines

Trefoil factor family (TFF) peptides have been shown to effect cell proliferation, apoptosis, migration and invasion of normal cells and various cancer cell lines. In the literature TFF peptides are controversially discussed as tumor suppressors and potential tumor progression factors. In the study presented, we investigated the effect of TFF3 overexpression on growth, viability, migration and tumorigenicity of the human retinoblastoma cell lines Y-79, WERI-Rb1, RBL-13 and RBL-15. As revealed by WST-1 and TUNEL assays as well as DAPI and BrdU cell counts, recombinant human TFF3 significantly lowers retinoblastoma cell viability and increases apoptosis levels. Transient TFF3 overexpression likewise significantly increases RB cell apoptosis. Stable, lentiviral TFF3 overexpression lowers retinoblastoma cell viability, proliferation and growth and significantly increases cell death in retinoblastoma cells. Blockage experiments using a broad-spectrum caspase inhibitor and capase-3 immunocytochemistry revealed the involvement of caspases in general and of caspase-3 in particular in TFF3 induced apoptosis in retinoblastoma cell lines. Soft agarose and in ovo chicken chorioallantoic membrane (CAM) assays revealed that TFF3 overexpression influences anchorage independent growth and significantly decreases the size of tumors forming from retinoblastoma cells. Our study demonstrates that forced TFF3 expression exerts a significant pro-apoptotic, anti-proliferative, and tumor suppressive effect in retinoblastoma cells, setting a starting point for new additive chemotherapeutic approaches in the treatment of retinoblastoma.

Neuropeptide Trefoil Factor 3 Reverses Depressive-Like Behaviors by Activation of BDNF-ERK-CREB Signaling in Olfactory Bulbectomized Rats

The trefoil factors (TFFs) are a family of three polypeptides, among which TFF1 and TFF3 are widely distributed in the central nervous system. Our previous study indicated that TFF3 was a potential rapid-onset antidepressant as it reversed the depressive-like behaviors induced by acute or chronic mild stress. In order to further identify the antidepressant-like effect of TFF3, we applied an olfactory bulbectomy (OB), a classic animal model of depression, in the present study. To elucidate the mechanism underlying the antidepressant-like activity of TFF3, we tested the role of brain-derived neurotrophic factor (BDNF)-extracellular signal-related kinase (ERK)-cyclic adenosine monophosphate response element binding protein (CREB) signaling in the hippocampus in the process. Chronic systemic administration of TFF3 (0.1 mg/kg, i.p.) for seven days not only produced a significant antidepressant-like efficacy in the OB paradigm, but also restored the expression of BDNF, pERK, and pCREB in the hippocampal CA3. Inhibition of BDNF or extracellular signal-related kinase (ERK) signaling in CA3 blocked the antidepressant-like activity of TFF3 in OB rats. Our findings further confirmed the therapeutic effect of TFF3 against depression and suggested that the normalization of the BDNF-ERK-CREB pathway was involved in the behavioral response of TFF3 for the treatment of depression.

Protective activity of salidroside against ethanol-induced gastric ulcer via the MAPK/NF-κB pathway in vivo and in vitro

Salidroside (Sal) is a traditional Chinese medicine with various pharmacological effects. The present study aimed to investigate the protective effect of Sal on ethanol-induced acute gastric ulcer and H2O2-induced gastric epithelial cell damage. 0.2 ml ethanol and 400 μM H2O2 were applied to establish a gastric ulcer model in vivo and in vitro respectively. The production of interleukin (IL)-6, interleukin (IL)-1β and tumor necrosis factor (TNF)-α was analyzed, as well as myeloperoxidase (MPO), malondialdehyde (MDA) and superoxide dismutase (SOD). MTT assay was used to detect cell viability. In addition, MAPK/NF-κB signal pathway-related proteins p-ERK, p-JNK, p-p38, p-IκBα and p-NF-κBp65 were analyzed to determine the underlying protective mechanism. Downstream genes such as cyclooxygenase-2 (COX-2), 5-lipoxygenase (5-LOX) and leukotrienes B4 (LTB4) were also measured. Obtained data indicated that Sal inhibited the overproduction of pro-inflammatory cytokines and enhanced antioxidant activity. Collectively, it is assumed that Sal could alleviate ethanol-induced acute gastric ulcer and H2O2-induced gastric epithelial cell damage through the MAPK/NF-κB pathway.