Determination of follistatin-like protein 1 expression in colorectal cancer and its association with clinical outcomes

Prognostic significance of the FSTL1-DIP2A axis in early-stage tongue cancer

In tongue cancer, many patients already have metastasis at the time of diagnosis, and such cases are usually unresponsive to treatment, resulting in a poor prognosis. Therefore, there is an urgent need to develop more effective diagnostic and therapeutic methods to cure tongue cancer at the earliest possible stage in clinical practice. Follistatin-like 1 (FSTL1) is known as a negative effector molecule that induces and enhances the refractoriness of cancer cells directly and indirectly via suppressing anti-tumor immunity in various types of cancer. However, the molecular expression, functions, and clinical significance of FSTL1 and its receptor DIP2A in tongue cancer remains to be elucidated. In this study, we revealed that FSTL1, which is highly expressed in tongue cancer cells, plays a key role in its malignancy and is a significant risk factor for recurrence of early-stage tongue cancer. Basic study shows that FSTL1 is abundantly produced from human tongue cancer cell lines, and blocking FSTL1 with specific siRNAs or mAb significantly suppresses cellular functions. Clinical study shows that both FSTL1 and its receptor DIP2A are highly and correlatively expressed in tumor tissues of tongue cancer patients, and high expression levels of both in stage I tumors are significantly associated with shorter relapse-free survival. These suggest that targeting the FSTL1-DIP2A axis may be useful as a biomarker for early prediction of prognosis in tongue cancer patients, and as a therapeutic target for developing new drugs to treat tongue cancer more effectively. This strategy will contribute to improving clinical outcomes in tongue cancer.

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.

The novel transcriptomic signature of angiogenesis predicts clinical outcome, tumor microenvironment and treatment response for prostate adenocarcinoma

Angiogenesis plays the critical roles in promoting tumor progression, aggressiveness, and metastasis. Although few studies have revealed some angiogenesis-related genes (ARGs) could serve as prognosis-related biomarkers for the prostate cancer (PCa), the integrated role of ARGs has not been systematically studied. The RNA-sequencing data and clinical information of prostate adenocarcinoma (PRAD) were downloaded from The Cancer Genome Atlas (TCGA) as discovery dataset. Twenty-three ARGs in total were identified to be correlated with prognosis of PRAD by the univariate Cox regression analysis, and a 19-ARG signature was further developed with significant correlation with the disease-free survival (DFS) of PRAD by the least absolute shrinkage and selection operator (LASSO) Cox regression with tenfold cross-validation. The signature stratified PRAD patients into high- and low-ARGs signature score groups, and those with high ARGs signature score were associated with significantly poorer outcomes (median DFS: 62.71 months vs unreached, p < 0.0001). The predicting ability of ARGs signature was subsequently validated in two independent cohorts of GSE40272 & PRAD_MSKCC. Notably, the 19-ARG signature outperformed the typical clinical features or each involved ARG in predicting the DFS of PRAD. Furthermore, a prognostic nomogram was constructed with three independent prognostic factors, including the ARGs signature, T stage and Gleason score. The predicted results from the nomogram (C-index = 0.799, 95%CI = 0.744-0.854) matched well with the observed outcomes, which was verified by the calibration curves. The values of area under receiver operating characteristic curve (AUC) for DFS at 1-, 3-, 5-year for the nomogram were 0.82, 0.83, and 0.83, respectively, indicating the performance of nomogram model is of reasonably high accuracy and robustness. Moreover, functional enrichment analysis demonstrated the potential targets of E2F targets, G2M checkpoint pathways, and cell cycle pathways to suppress the PRAD progression. Of note, the high-risk PRAD patients were more sensitive to immune therapies, but Treg might hinder benefits from immunotherapies. Additionally, this established tool also could predict response to neoadjuvant androgen deprivation therapy (ADT) and some chemotherapy drugs, such as cisplatin, paclitaxel, and docetaxel, etc. The novel ARGs signature, with prognostic significance, can further promote the application of targeted therapies in different stratifications of PCa patients.

CD11b+DIP2A+LAG3+ cells facilitate immune dysfunction in colorectal cancer

Colorectal cancer (CRC) is one of the most common malignant tumors worldwide, and tumor metastasis is the leading cause of death. Targeting immune inhibitory checkpoint inhibitory pathways has attracted great attention, since the therapeutic efficacy induced by the specific blocking antibodies has been demonstrated even in metastatic CRC patients. However, the clinical outcome is low in many cases, and thus more effective treatments are needed in the clinical settings. A SPARC family member follistatin-like 1 (FSTL1) is known as a key driver of tumor metastasis in various types of cancer. However, the immunological roles of the FSTL1 in the CRC pathogenesis remain to be elucidated. In this study, we investigated the molecular mechanisms underlying the refractory FSTL1⁺ CRC using murine and human FSTL1-transduced CRC cells. Also, based on the results, we evaluated anti-tumor efficacy induced by agents targeting the identified molecules using murine CRC metastasis models, and validated the clinical relevancy of the basic findings using tumor tissues and peripheral blood obtained from CRC patients. FSTL1 transduction conferred EMT-like properties, such as low proliferative (dormant) and high invasive abilities, on tumor cells. When the transfectants were subcutaneously implanted in mice, CD11b⁺DIP2A⁺LAG3⁺ cells were abundantly expanded locally and systemically in the mice. Simultaneously, apoptotic T cells increased and were lastly excluded from the tumor tissues, allowing tumor aggravation leading to resistance to anti-PD1/PDL1 treatment. Blocking FSTL1 and LAG3, however, significantly suppressed the apoptosis induction, and successfully induced anti-tumor immune responses in the CRC metastasis models. Both treatments synergized in providing better prognosis of the mice. FSTL1 was significantly upregulated in tumor tissues and peripheral blood of CRC patients, and the CD11b⁺DIP2A⁺LAG3⁺ cells were significantly expanded in the PBMCs as compared to those of healthy donors. The expansion level was significantly correlated with decrease of potent Ki67⁺GZMB⁺ CTLs. These results suggest that the FSTL1-induced CD11b⁺DIP2A⁺LAG3⁺ cells are a key driver of immune dysfunction in CRC. Targeting the FSTL1-LAG3 axis may be a promising strategy for treating metastatic CRC, and anti-FSTL1/LAG3 combination regimen may be practically useful in the clinical settings.

Follistatin-Like Proteins: Structure, Functions and Biomedical Importance

Main forms of cellular signal transmission are known to be autocrine and paracrine signaling. Several cells secrete messengers called autocrine or paracrine agents that can bind the corresponding receptors on the surface of the cells themselves or their microenvironment. Follistatin and follistatin-like proteins can be called one of the most important bifunctional messengers capable of displaying both autocrine and paracrine activity. Whilst they are not as diverse as protein hormones or protein kinases, there are only five types of proteins. However, unlike protein kinases, there are no minor proteins among them; each follistatin-like protein performs an important physiological function. These proteins are involved in a variety of signaling pathways and biological processes, having the ability to bind to receptors such as DIP2A, TLR4, BMP and some others. The activation or experimentally induced knockout of the protein-coding genes often leads to fatal consequences for individual cells and the whole body as follistatin-like proteins indirectly regulate the cell cycle, tissue differentiation, metabolic pathways, and participate in the transmission chains of the pro-inflammatory intracellular signal. Abnormal course of these processes can cause the development of oncology or apoptosis, programmed cell death. There is still no comprehensive understanding of the spectrum of mechanisms of action of follistatin-like proteins, so the systematization and study of their cellular functions and regulation is an important direction of modern molecular and cell biology. Therefore, this review focuses on follistatin-related proteins that affect multiple targets and have direct or indirect effects on cellular signaling pathways, as well as to characterize the directions of their practical application in the field of biomedicine.

Myokines in treatment-naïve patients with cancer-associated cachexia

Cancer-associated cachexia is a complex metabolic syndrome characterized by weight loss and systemic inflammation. Muscle loss and fatty infiltration into muscle are associated with poor prognosis in cancer patients. Skeletal muscle secretes myokines, factors with autocrine, paracrine and/or endocrine action, which may be modified by or play a role in cachexia. This study examined myokine content in the plasma, skeletal muscle and tumor homogenates from treatment-naïve patients with gastric or colorectal stages I-IV cancer with cachexia (CC, N = 62), or not (weight stable cancer, WSC, N = 32). Myostatin, interleukin (IL) 15, follistatin-like protein 1 (FSTL-1), fatty acid binding protein 3 (FABP3), irisin and brain-derived neurotrophic factor (BDNF) protein content in samples was measured with Multiplex technology; body composition and muscle lipid infiltration were evaluated in computed tomography, and quantification of triacylglycerol (TAG) in the skeletal muscle. Cachectic patients presented lower muscle FSTL-1 expression (p = 0.047), higher FABP3 plasma content (p = 0.0301) and higher tumor tissue expression of FABP3 (p = 0.0182), IL-15 (p = 0.007) and irisin (p = 0.0110), compared to WSC. Neither muscle TAG content, nor muscle attenuation were different between weight stable and cachectic patients. Lumbar adipose tissue (AT) index, visceral AT index and subcutaneous AT index were lower in CC (p = 0.0149, p = 0.0455 and p = 0.0087, respectively), who also presented lower muscularity in the cohort (69.2% of patients; p = 0.0301), compared to WSC. The results indicate the myokine profile in skeletal muscle, plasma and tumor is impacted by cachexia. These findings show that myokines eventually affecting muscle wasting may not solely derive from the muscle itself (as the tumor also may contribute to the systemic scenario), and put forward new perspectives on cachexia treatment targeting myokines and associated receptors and pathways.

Sulforaphene inhibits the progression of osteosarcoma via regulating FSTL1/NF-κB pathway

AIMS

Sulforaphene (SFE), a naturally occurring isothiocyanate found in cruciferous vegetables, has attracted increasing attention for its anti-cancer effect in many cancers.

MAIN METHODS

We explored the therapeutic effects of SFE in modulating the progression of osteosarcoma. CCK8 assay, colony formation assay, western blot, wounding healing assay and transwell assay were conducted to detect the proliferation, apoptosis, migration and invasion of osteosarcoma cells (U2OS and Saos2) treated with different concentrations of SFE. In addition, tumor xenograft in nude mice is performed to test the effects of SFE in tumorigenesis in vivo. Moreover, the levels of FSTL1 and NF-κB were determined by western blot, and loss of functions of FATL1 and NF-κB were further conducted to evaluate the underlying mechanisms of SFE on osteosarcoma development.

KEY FINDINGS

The results revealed that SFE inhibited the growth while promoted apoptosis of U2OS and Saos2 cells in a dose-dependent manner. Mechanistically, SFE significantly inhibited the expression of NF-κB and FSTL1. However, the genetic intervention of FSTL1 or pharmacologically inhibiting NF-κB weakened the anti-tumor role of SFE.

SIGNIFICANCE

This study suggested that SFE alleviates the progression of osteosarcoma through modulating the FSTL1/NF-κB pathway.