Follistatin-like protein 1 sustains colon cancer cell growth and survival

Prospects of new targeted nanotherapy combining liponiosomes with berberine to combat colorectal cancer development: An in vivo experimental model

Colorectal cancer (CRC) is one of the most identified and deadly malignancies worldwide. It presents a serious challenge due to its quick growth, which finally culminates in severe malignancy. It is critical to improve the efficacy of berberine (BR) as an anticancer agent to overcome its limited bioavailability. Implementation of a novel, effective nanocarrier system of liponiosomes for BR (LipoNio.BR) can support mechanistic actions associated with its anti-CRC role. Following CRC induction in rats using 1,2 Dimethylhydrazine (40 mg DMH/kg/week), the potency and mechanistic actions of LipoNio.BR were assessed by evaluating the lesion severity and molecular mechanisms controlling oxidative stress, apoptosis, autophagy, and inflammatory responses, and conducting histopathological and immunohistochemistry examinations of colonic tissues. The results indicated that the severity of clinical signs comprising weight gain loss, increased diarrhea and rectal bleeding, and reduced survivability were greatly restored in the LipoNio.BR-treated group. LipoNio.BR remarkably reduced CRC development compared to FBR (free berberine), as it induced apoptosis via upregulating apoptotic genes (Bax and caspase3, increased up to 7.89 and 6.25-fold, respectively) and downregulating the anti-apoptotic gene Bcl-2 by 2.25-fold. LipoNio.BR mitigated the oxidative stress associated with CRC and maintained redox homeostasis. Notably, the excessive inflammatory response associated with CRC was prominently reduced following administration of LipoNio.BR [which decreased iterleukin (IL-B, IL-6), tumor necrosis factor-alpha (TNF-α), cyclooxygenase-2 (COX2), inducible nitric oxide synthase (iNOS), proliferating cell nuclear antigen (PCNA), follistatin, and activin BA (beta-A) expression]. LipoNio.BR modulated the expression of nuclear factor kappa B (NF-κB) and mammalian target of rapamycin (mTOR), which impacted tumor vascularity (decreased Vascular endothelial growth factor (VEGF) expression by 2.36-fold). The severity of the histopathological alterations in the colonic tissues, including the development of neoplastic epithelium and the invasion of some neoplastic masses, was greatly reduced in the LipoNio.BR group compared to the FBR-(free berberine) administrated group. Following CRC induction, immunohistochemical staining revealed that the overexpression of cyclin and COX-2 in colonic tissues were suppressed in the LipoNio.BR group. Taken together, these findings suggest that LipoNio.BR has a potential role in reducing CRC progression to a greater extent compared to free BR and could be considered a promising and potent therapy against CRC.

lncRNA TRPM2-AS Promotes Colorectal Cancer Progression by Regulating miR-22-3p and FSTL1

Background. In recent years, long noncoding RNAs (lncRNAs) relate to many biological processes, which affect the progression of tumors. Transient receptor potential melastatin 2 antisense RNA (TRPM2-AS) is reported to play an oncogene-like role in tumors. TRPM2-AS is highly expressed in colorectal cancer (CRC), but the mechanism of TRPM2-AS is still unclear. The regulatory mechanism of TRPM2-AS in the occurrence of CRC was explored, so as to find new markers and therapeutic targets for CRC. Methods. TRPM2-AS and miR-22-3p expression in CRC cells were measured through reverse-transcription quantitative polymerase chain reaction (RT-qPCR). Then, TRPM2-AS knockdown cell lines were constructed, and cell counting kit-8 (CCK-8), clone formation, wound healing, and invasion assays were used to detect cell malignant behavior. Follistatin-like 1 (FSTL1) protein was detected by western blotting. The interaction between miR-22-3p and TRPM2-AS or FSTL1 was verified by the luciferase reporter and RNA immunoprecipitation (RIP) assay. Subcutaneous xenografts were performed using animal experiments. Results. TRPM2-AS expression in CRC cells was increased, and miR-22-3p expression was decreased in CRC cells. TRPM2-AS inhibition inhibited cell malignant behavior. miR-22-3p has a targeting relationship with TRPM2-AS and FSTL1. In cells, downregulation of TRPM2-AS expression promoted miR-22-3p and inhibited FSTL1 expression, while mimics inhibited FSTL1 expression. miR-22-3p inhibition or FSTL1 overexpression could offset the inhibition of TRPM2-AS downregulation on CRC cells. Conclusions. The TRPM2-AS/miR-22-3p/FSTL1 regulation axis could regulate CRC cell malignant behavior, which may provide a new perspective for interpreting the mechanism of CRC development.

FSTL1 Secreted by Activated Fibroblasts Promotes Hepatocellular Carcinoma Metastasis and Stemness

The tumor microenvironment plays a critical role in maintaining the immature phenotype of tumor-initiating cells (TIC) to promote cancer. Hepatocellular carcinoma (HCC) is a unique disease in that it develops in the setting of fibrosis and cirrhosis. This pathologic state commonly shows an enrichment of stromal myofibroblasts, which constitute the bulk of the tumor microenvironment and contribute to disease progression. Follistatin-like 1 (FSTL1) has been widely reported as a proinflammatory mediator in different fibrosis-related and inflammatory diseases. Here we show FSTL1 expression to be closely correlated with activated fibroblasts and to be elevated in regenerative, fibrotic, and disease liver states in various mouse models. Consistently, FSTL1 lineage cells gave rise to myofibroblasts in a CCL₄-induced hepatic fibrosis mouse model. Clinically, high FSTL1 in fibroblast activation protein-positive (FAP⁺) fibroblasts were significantly correlated with more advanced tumors in patients with HCC. Although FSTL1 was expressed in primary fibroblasts derived from patients with HCC, it was barely detectable in HCC cell lines. Functional investigations revealed that treatment of HCC cells and patient-derived 3D organoids with recombinant FSTL1 or with conditioned medium collected from hepatic stellate cells or from cells overexpressing FSTL1 could promote HCC growth and metastasis. FSTL1 bound to TLR4 receptor, resulting in activation of AKT/mTOR/4EBP1 signaling. In a preclinical mouse model, blockade of FSTL1 mitigated HCC malignancy and metastasis, sensitized HCC tumors to sorafenib, prolonged survival, and eradicated the TIC subset. Collectively, these data suggest that FSTL1 may serve as an important novel diagnostic/prognostic biomarker and therapeutic target in HCC. SIGNIFICANCE: This study shows that FSTL1 secreted by activated fibroblasts in the liver microenvironment augments hepatocellular carcinoma malignancy, providing a potential new strategy to improve treatment of this aggressive disease.

HuR enhances FSTL1 transcript stability to promote invasion and metastasis of squamous cell carcinoma

Squamous cell carcinoma (SCC) is a lethal malignancy with a high propensity for metastasis. Follistatin-like 1 (FSTL1), a pro-metastatic glycoprotein, is absent from healthy epithelia and aberrantly upregulated in SCC. The FSTL1 transcript encodes two alternative gene products whose dominance is post-transcriptionally regulated via a bistable switch. In healthy epithelia, FSTL1 mRNA is destabilized by binding of KH-type splicing regulatory protein (KSRP), and processed as a primary microRNA encoding miR-198. In SCC, KSRP downregulation terminates miR-198 processing, enabling FSTL1 translation. Here, we identify HuR (Human Antigen R) as an upstream regulator of FSTL1 and describe how downregulation of KSRP is permissive, but not sufficient, to promote sustained FSTL1 expression. Moreover, we demonstrate how the interplay between two RNA-binding proteins controls the translation of pro-oncogenic FSTL1. Increased expression of HuR in SCC outcompetes KSRP and enhances FSTL1 transcript stability, enabling persistent FSTL1 expression and activation of downstream metastatic pathways.

Endothelial cells exposed to atheroprotective flow secrete follistatin-like 1 protein which reduces transcytosis and inflammation

BACKGROUND AND AIMS

When endothelium is cultured in wells swirled on an orbital shaker, cells at the well centre experience putatively atherogenic flow whereas those near the edge experience putatively atheroprotective flow. Transcellular transport is decreased equally in both regions, consistent with it being reduced by a mediator released from cells in one part of the well and mixed in the swirling medium. Similar effects have been inferred for pro-inflammatory changes. Here we identify the mediator and flow characteristics stimulating its release.

METHODS AND RESULTS

Medium conditioned by cells swirled at the edge, but not by cells swirled at the centre or cultured under static conditions, significantly reduced transendothelial transport of a low density lipoprotein (LDL)-sized tracer and tumor necrosis factor α (TNF-α)-induced activation and translocation of nuclear factor κB (NF-κB), adhesion molecule expression and monocyte adhesion. Inhibiting transcytosis similarly decreased tracer transport. Unbiased proteomics revealed that cells from the swirled edge secreted substantially more follistatin-like 1 (FSTL1) than cells from the swirled centre or from static wells. Exogenous FSTL1 reduced transport of the LDL-sized tracer and of LDL itself, as well as TNF-α-induced adhesion molecule expression. Bone morphogenetic protein 4 (BMP4) increased transport of the LDL-sized tracer and adhesion molecule expression; FSTL1 abolished these effects.

CONCLUSIONS

Putatively atheroprotective flow stimulates secretion of FSTL1 by cultured endothelial cells. FSTL1 reduces transcellular transport of LDL-sized particles and of LDL itself, and inhibits endothelial activation. If this also occurs in vivo, it may account for the atheroprotective nature of such flow.

FSTL1 promotes growth and metastasis in gastric cancer by activating AKT related pathway and predicts poor survival

Accumulating evidence on the role of Follistatin-like protein 1 (FSTL1) in tumorigenesis and cancer progression is conflicting. Nevertheless, the underlying mechanisms by which FSTL1 contributes to gastric cancer (GC) remain unknown. This study shows that FSTL1 was frequently upregulated in primary GC tissues and significantly correlated with infiltrating depth, lymph node metastasis, unfavorable tumor stage and poor prognosis of GC. Down or up-regulation of FSTL1 inhibited or increased, respectively, the proliferation by reducing apoptosis, clonogenicity, migration and invasion of GC cells in vitro. Moreover, the higher expression of FSTL1 promoted subcutaneous xenograft tumor growth and lung/liver tumor metastasis in vivo. Furthermore, we demonstrate that FSTL1 is involved in regulation of the AKT signaling through analyzing databases and experimental results. Mechanistic studies showed that FSTL1 promoted proliferation, migration and invasion in GC, at least partially, by activating AKT via regulating TLR4/CD14. In all, this study highlights the role of the FSTL1-TLR4/CD14-AKT axis, which provided novel insights into the mechanism of growth and metastasis in GC for the first time.

MiR-524-5p Suppresses Migration, Invasion, and EMT Progression in Breast Cancer Cells Through Targeting FSTL1

Background: The effects of miR-524-5p on breast cancer (BC) have not been investigated, though studies show that miR-524-5p has an anticancer function. Thus, this study investigated the effects of miR-524-5p on BC cells and its potential molecular mechanism. Materials and Methods: The expression of miR-524-5p from the collected BC samples was determined. Cell counting kit-8 (CCK-8) assay was performed to examine the effect of miR-524-5p on BC cells viability. The target for miR-524-5p was predicted by bioinformatics and further verified by luciferase assay. Wound healing assay and transwell assay were performed to determine cell migration and invasion of BC cells. The expressions of Follistatin-like 1 (FSTL1) and related proteins in epithelial-mesenchymal transition (EMT) were detected by Western blotting and quantitative real-time polymerase chain reaction. Results: MiR-524-5p was low-expressed in BC samples, and upregulation of miR-524-5p suppressed BC cell viability, migration, and invasion. FSTL1 was predicted as a target for miR-524-5p. In addition, overexpressed FSTL1 effectively abolished the effect of miR-524-5p on inhibiting FSTL1 expression, and reversed the inhibitory effects of miR-524-5p on the migration, invasion of BC cells as well as the effect of miR-524-5p on regulating the expressions of matrix metalloproteinase 2 (MMP2), matrix metalloproteinase 9 (MMP9), E-cadherin, and N-cadherin. Conclusions: Our findings suggest that miR-524-5p targeting FSTL1 adversely affects the progression of migration, invasion, and EMT of BC cells, thus, miR-524-5p is possibly a target for BC treatment.