Transforming Growth Factor-β1 as a Predictor for the Development of Hepatocellular Carcinoma: A Nested Case-Controlled Study

TGF-β signaling in health, disease, and therapeutics

Transforming growth factor (TGF)-β is a multifunctional cytokine expressed by almost every tissue and cell type. The signal transduction of TGF-β can stimulate diverse cellular responses and is particularly critical to embryonic development, wound healing, tissue homeostasis, and immune homeostasis in health. The dysfunction of TGF-β can play key roles in many diseases, and numerous targeted therapies have been developed to rectify its pathogenic activity. In the past decades, a large number of studies on TGF-β signaling have been carried out, covering a broad spectrum of topics in health, disease, and therapeutics. Thus, a comprehensive overview of TGF-β signaling is required for a general picture of the studies in this field. In this review, we retrace the research history of TGF-β and introduce the molecular mechanisms regarding its biosynthesis, activation, and signal transduction. We also provide deep insights into the functions of TGF-β signaling in physiological conditions as well as in pathological processes. TGF-β-targeting therapies which have brought fresh hope to the treatment of relevant diseases are highlighted. Through the summary of previous knowledge and recent updates, this review aims to provide a systematic understanding of TGF-β signaling and to attract more attention and interest to this research area.

Clinical assessment of TGFB1 and HP Relative Gene Expression in the Peripheral Blood of Prostate Cancer Patients

OBJECTIVE

This study aimed to assess the relative gene expression level of transforming growth factor-β1 (TGFB1) and haptoglobin (HP) in the peripheral blood of prostate cancer (PCa) patients and evaluate their diagnostic ability.

METHODS

A total of 125 participants were enrolled in the present study. Among them, 75 PCa patients, 25 benign prostatic hyperplasia (BPH) patients, and 25 healthy volunteers served as the control group. The relative TGFB1 and HP gene expression level was quantified using real-time polymerase chain reaction. Further, free and total PSA levels were determined using electrochemiluminescence assays.

RESULTS

TGFB1 was significantly over-expressed, whereas HP was significantly downregulated in the peripheral blood of PCa patients compared to BPH and control groups (p-value ranges from 0.034 to <0.001). Moreover, the high expression level of TGFB1 was associated with an increased risk of PCa development with OR=1.412 (95%CI: 1.081-1.869, p= 0.012). TGFB1 and HP relative expression levels had lower diagnostic performance to differentiate PCa from normal and BPH individuals compared to PSA, however, the combination of the tested parameters improved the diagnostic efficacy.

CONCLUSIONS

TGFB1 and HP relative expression have moderate diagnostic efficacy in discriminating patients with PCa from BPH and healthy subjects. Furthermore, over-expression of TGFB1 may contribute to the pathogenesis of PCa.

Association between serum carotenoids and premature mortality in a population-based case-control study

Carotenoids are abundant pigments mainly contained in vegetables and fruits, and show antioxidant properties by quenching free radicals in human body. Few studies have investigated associations between serum carotenoid levels and premature mortality. The objective of this study was to investigate the association between serum carotenoid level and premature mortality in a Japanese population. This study included 446 Japanese adults (174 men, aged of 40-64) recruited as participants in the Japan Collaborative Cohort (JACC) Study. Serum carotenoid level was measured by high-performance liquid chromatography. Premature mortality was defined as death before 65 years old during the follow-up period. Premature mortality was ascertained in 60 men (34.5%) and 65 women (23.9%). In men, compared to the 1^st tertile of serum β-cryptoxanthin and provitamin A, those who were in the 3^rd tertile had lower risks of premature all-cause mortality (OR, 95% CI: 0.19, 0.07-0.47 for β-cryptoxanthin, and 0.24, 0.09-0.61 for provitamin A). In women, compared to the 1^st tertile of serum β-cryptoxanthin, those who were in the 3^rd tertile had higher risks of premature all-cause mortality (OR, 95% CI: 1.94, 1.00-4.03). These significant associations were observed in analyses for premature cancer mortality. We found significant associations between higher levels of serum β-cryptoxanthin and provitamin A and lower risks of premature mortality among Japanese men, while a different directional association was found in women. Although these findings suggest roles of serum carotenoids on premature mortality, further studies are needed to validate this association in other populations.

miR-744-5p suppresses tumor proliferation and metastasis by targeting transforming growth factor-beta 1 (TGF-β1) in hepatocellular carcinoma (HCC)

BACKGROUND

microRNAs (miRNAs) have been shown to significantly contribute to the pathogenesis of various tumors, including hepatocellular carcinoma (HCC). Specifically, miR-744-5p has been shown to be associated with tumor development, but the underlying mechanism by which miR-744-5p affects HCC remains unclear. Thus, this study sought to explore the molecular mechanism governing the function of miR-744-5p in HCC.

METHODS

The expression of miR-744-5p in HCC tissues/cells was detected by quantitative reverse transcription polymerase chain reaction (qRT-PCR). Colony-formation, cell-counting kit 8 (CCK-8), Transwell, and wound-healing assays were used to assess the proliferation and metastasis of HCC cells. Additionally, the interaction between miR-744-5p and transforming growth factor-beta 1 (TGF-β1) was detected using a dual-luciferase reporter and a Western-blot analysis.

RESULTS

miR-744-5p expression was shown to be significantly reduced in HCC tissues and cells. The overexpression of miR-744-5p not only significantly inhibited HCC cell proliferation, but also significantly reduced epithelial-mesenchymal transition-induced invasion. A luciferase reporter assay validated the ability of miR-744-5p to directly target TGF-β1. Further, the overexpression of TGF-β1 appeared to abolish the inhibitive effect of miR-744-5p mimics on HCC development.

CONCLUSIONS

As per our findings, it was revealed that miR-744-5p suppresses HCC proliferation and invasion by regulating the TGF-β1 signaling pathway and epithelial-mesenchymal-transition (EMT).

Novel therapies emerging in oncology to target the TGF-β pathway

The TGF-β signaling pathway governs key cellular processes under physiologic conditions and is deregulated in many pathologies, including cancer. TGF-β is a multifunctional cytokine that acts in a cell- and context-dependent manner as a tumor promoter or tumor suppressor. As a tumor promoter, the TGF-β pathway enhances cell proliferation, migratory invasion, metastatic spread within the tumor microenvironment and suppresses immunosurveillance. Collectively, the pleiotropic nature of TGF-β signaling contributes to drug resistance, tumor escape and undermines clinical response to therapy. Based upon a wealth of preclinical studies, the TGF-β pathway has been pharmacologically targeted using small molecule inhibitors, TGF-β-directed chimeric monoclonal antibodies, ligand traps, antisense oligonucleotides and vaccines that have been now evaluated in clinical trials. Here, we have assessed the safety and efficacy of TGF-β pathway antagonists from multiple drug classes that have been evaluated in completed and ongoing trials. We highlight Vactosertib, a highly potent small molecule TGF-β type 1 receptor kinase inhibitor that is well-tolerated with an acceptable safety profile that has shown efficacy against multiple types of cancer. The TGF-β ligand traps Bintrafusp alfa (a bifunctional conjugate that binds TGF-β and PD-L1), AVID200 (a computationally designed trap of TGF-β receptor ectodomains fused to an Fc domain) and Luspatercept (a recombinant fusion that links the activin receptor IIb to IgG) offer new ways to fight difficult-to-treat cancers. While TGF-β pathway antagonists are rapidly emerging as highly promising, safe and effective anticancer agents, significant challenges remain. Minimizing the unintentional inhibition of tumor-suppressing activity and inflammatory effects with the desired restraint on tumor-promoting activities has impeded the clinical development of TGF-β pathway antagonists. A better understanding of the mechanistic details of the TGF-β pathway should lead to more effective TGF-β antagonists and uncover biomarkers that better stratify patient selection, improve patient responses and further the clinical development of TGF-β antagonists.

Circulating miR-21, miR-29a, and miR-126 are associated with premature death risk due to cancer and cardiovascular disease: the JACC Study

Primary prevention of premature death is a public health concern worldwide. Circulating microRNAs (miRNAs) have been described as potential diagnostic biomarkers for diseases as cancer and cardiovascular disease (CVD). This case-cohort study aimed to investigate the potential relationship between circulating miRNAs and the risk of premature death. A total of 39,242 subjects provided baseline serum samples in 1988–1990. Of these, 345 subjects who died of intrinsic disease (< 65 years old) and for which measurable samples were available were included in this study. We randomly selected a sub-cohort of 879 subjects. Circulatring miR-21, miR-29a, and miR-126 were determined using qRT-PCR. Conditional logistic regression models were used to analyse the data with respect to stratified miRNA levels. Multivariable logistic regression revealed that subjects with high circulating miR-21 and miR-29a individual levels had a significantly higher risk of total death, cancer death, and CVD death than those with medium miR-21 and miR-29a individual levels. Conversely, subjects with low circulating miR-126 levels had a significantly higher risk of total death than those with medium levels. This suggests that circulating miRNAs are associated with the risk of premature death from cancer and CVD, identifying them as potential biomarkers for early detection of high-risk individuals.

Targeting Liver Cancer Stem Cells: An Alternative Therapeutic Approach for Liver Cancer

The first report of cancer stem cell (CSC) from Bruce et al. has demonstrated the relatively rare population of stem-like cells in acute myeloid leukemia (AML). The discovery of leukemic CSCs prompted further identification of CSCs in multiple types of solid tumor. Recently, extensive research has attempted to identity CSCs in multiple types of solid tumors in the brain, colon, head and neck, liver, and lung. Based on these studies, we hypothesize that the initiation and progression of most malignant tumors rely largely on the CSC population. Recent studies indicated that stem cell-related markers or signaling pathways, such as aldehyde dehydrogenase (ALDH), CD133, epithelial cell adhesion molecule (EpCAM), Wnt/β-catenin signaling, and Notch signaling, contribute to the initiation and progression of various liver cancer types. Importantly, CSCs are markedly resistant to conventional therapeutic approaches and current targeted therapeutics. Therefore, it is believed that selectively targeting specific markers and/or signaling pathways of hepatic CSCs is an effective therapeutic strategy for treating chemotherapy-resistant liver cancer. Here, we provide an overview of the current knowledge on the hepatic CSC hypothesis and discuss the specific surface markers and critical signaling pathways involved in the development and maintenance of hepatic CSC subpopulations.

Circulating biomarkers for early detection of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is estimated to be the fourth leading cause of cancer-related deaths worldwide. HCC patients face a dismal prognosis because symptoms usually appear in an advanced stage of disease. The detection of early stage HCC allows for curative surgical treatment and therefore saves lives. Specific non-invasive or diagnostic markers for HCC may represent a valuable tool for detecting these tumors at an early stage. The clinically most established serological biomarker alpha-fetoprotein shows only limited diagnostic performance, however novel candidate biomarkers and biomarker panels for detecting HCC at early stages of development are being studied. In this review we will discuss the findings of these studies.

Contextual Regulation of TGF-β Signaling in Liver Cancer

Primary liver cancer is one of the leading causes for cancer-related death worldwide. Transforming growth factor beta (TGF-β) is a pleiotropic cytokine that signals through membrane receptors and intracellular Smad proteins, which enter the nucleus upon receptor activation and act as transcription factors. TGF-β inhibits liver tumorigenesis in the early stage by inducing cytostasis and apoptosis, but promotes malignant progression in more advanced stages by enhancing cancer cell survival, EMT, migration, invasion and finally metastasis. Understanding the molecular mechanisms underpinning the multi-faceted roles of TGF-β in liver cancer has become a persistent pursuit during the last two decades. Contextual regulation fine-tunes the robustness, duration and plasticity of TGF-β signaling, yielding versatile albeit specific responses. This involves multiple feedback and feed-forward regulatory loops and also the interplay between Smad signaling and non-Smad pathways. This review summarizes the known regulatory mechanisms of TGF-β signaling in liver cancer, and how they channel, skew and even switch the actions of TGF-β during cancer progression.

TGF-β1 promotes cell migration in hepatocellular carcinoma by suppressing reelin expression

Hepatocellular carcinoma (HCC) is the most common type of primary liver cancer in adults and is a leading cause of worldwide cancer mortality. Intrahepatic dissemination and extrahepatic metastasis are key factors in malignant growth of HCC. Reducing HCC-associated metastasis is critically dependent on uncovering molecular signaling pathways that promote HCC metastasis. In this study, we explored the effect of TGF-β1 and RELN on cell migration, and the relationship between TGF-β1 and RELN in HCC cells. The data presented that TGF-β1 and RELN showed an opposite expression pattern, and either increased expression of TGF-β1 or decreased expression of RELN increased HCC cell migration ability. We also found TGF-β1 enhanced cell migration ability was through repressing RELN expression, as overexpression of RELN impaired TGF-β1 enhanced cell migration. Our work revealed the relationship between TGF-β1 and RELN and uncovered the important role of RELN in suppressing cell migration in HCC cells.

Deciphering Platelet Kinetics in Diagnostic and Prognostic Evaluation of Hepatocellular Carcinoma

Liver pathophysiology can, directly and indirectly, impose morphological or biochemical abnormalities of the platelets. Conversely, platelets are also able to regulate the promitogenic and profibrotic signals on liver pathobiology. Platelet contribution to the liver pathophysiology is typically facilitated by the platelet-derived growth factors that are sequestered in different subsets of alpha and dense granules, and the release of these growth factors is synchronized according to the stage and type of liver disease or injury. Thus, platelets harbor clinically relevant information with potential diagnostic and prognostic implications in liver diseases. Hepatocellular carcinoma (HCC) largely influences the platelet kinetics, and a growing body of evidence has recognized its association with HCC occurrence or prognosis. This narrative review summarizes the progress made on implicating platelet as a diagnostic and prognostic tool for HCC; the review also dissects the contradictory results from earlier studies and reflects how combining platelet-based information may enable more reliable test for diagnostic and prognostic evaluation of HCC.

Substrate stiffness promotes latent TGF-β1 activation in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) was usually coupled with increased stiffness of the extracellular matrix (ECM) and elevated level of transforming growth factor-β1 (TGF-β1). However, the mechanism by which substrate rigidity modulated TGF-β1 signaling transduction remained unknown. This paper investigated the molecular mechanism of how matrix stiffness regulating TGF-β1 signaling in HCC cells. By means of stiffness tunable collagen I-coated polyacrylamide (PA) gels, we found that the expressions of β1 integrin, p-FAK ^Y397 and p-Smad2 upregulated on stiffer gels as well as the content of TGF-β1 in culture media of HCC cells, which were inhibited by RGD blocking peptides, Y-27632 (ROCK inhibitor) or Blebbistatin (myosin II inhibitor). Cellular traction force was also significantly higher when plated on stiffer substrates but dramatically decreased after treatment with Y-27632 or Blebbistatin. Furthermore, the upregulation of p-Smad2 in the HCC cells on stiffer PA gels induced by exogenetic latent TGF-β1 was downregulated in the presence of RGD peptides. The nuclear translocation of Smad2 induced by latent TGF-β1 was inhibited by Y-27632 or Blebbistatin. Our results suggested that the extracellular matrix stiffness regulated latent TGF-β1 activation by cytoskeletal tension in HCC cells, showing that matrix stiffness was a key regulator involving the TGF-β1 activity in HCC cells. The current study presented a mechanism of how hepatocirrhosis developed into liver cancer.