Enhanced FHL2 and TGF-β1 Expression Is Associated With Invasive Growth and Poor Survival in Malignant Melanomas

High level of FHL2 exacerbates the outcome of non-small cell lung cancer (NSCLC) patients and the malignant phenotype in NSCLC cells

Non-small cell lung cancer (NSCLC) is a malignant tumour with high mortality. FHL2 has been identified as a biomarker of lung cancer. This research explored the effects of FHL2 expression on NSCLC. NSCLC-associated data sets were collected from the assistant for clinical bioinformatics and TCGA databases respectively. The association between FHL2 and clinical characteristics, the prognostic significance of FHL2 and the influences of various variables on NSCLC were determined by Pearson's chi-squared test, the Kaplan-Meier curve and the Cox regression model respectively. FHL2 level was altered by cell transfection and was measured by qRT-PCR. Tumour xenograft formation was completed by inoculating sh-FHL2/pcDNA-FHL2 transfected cells into BALB/c nude mice. Protein expression was assessed by western blot. Cell apoptosis, proliferation and epithelial - mesenchymal transition (EMT) characteristics were evaluated employing TUNEL, BrdU⁺ and microscopic observation respectively. The expression of Ki67 and N-cadherin was assessed by immunohistochemistry. The results showed that FHL2 was highly expressed in NSCLC tissues. Patients with high FHL2 expression experienced lower overall survival probability. FHL2 knockdown promoted apoptosis, but inhibited EMT of A549 and NCI-H460 cells, which was verified by the increased ratios of cleaved caspase 9/caspase 9 and cleaved caspase 3/caspase 3, as well as augmented E-cadherin and reduced N-cadherin. In an in vivo assay FHL2 knockdown decreased tumour volume and weight, repressed EMT, but enhanced apoptosis. FHL2 upregulation showed the opposite effects of FHL2 knockdown. Furthermore, FHL2 upregulation facilitated cell proliferation both in in vitro and in vivo assays. These outcomes indicated that high level of FHL2 facilitated tumorigenesis, as well as the proliferation and EMT of NSCLC cells.

Clinical Significance and Immunometabolism Landscapes of a Novel Recurrence-Associated Lipid Metabolism Signature In Early-Stage Lung Adenocarcinoma: A Comprehensive Analysis

Background

The early-stage lung adenocarcinoma (LUAD) rate has increased with heightened public awareness and lung cancer screening implementation. Lipid metabolism abnormalities are associated with lung cancer initiation and progression. However, the comprehensive features and clinical significance of the immunometabolism landscape and lipid metabolism-related genes (LMRGs) in cancer recurrence for early-stage LUAD remain obscure.

Methods

LMRGs were extracted from Gene Set Enrichment Analysis (GSEA) and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases. Samples from The Cancer Genome Atlas (TCGA) were used as training cohort, and samples from four Gene Expression Omnibus (GEO) datasets were used as validation cohorts. The LUAD recurrence-associated LMRG molecular pattern and signature was constructed through unsupervised consensus clustering, time-dependent receiver operating characteristic (ROC), and least absolute shrinkage and selection operator (LASSO) analyses. Kaplan-Meier, ROC, and multivariate Cox regression analyses and prognostic meta-analysis were used to test the suitability and stability of the signature. We used Gene Ontology (GO), KEGG pathway, immune cell infiltration, chemotherapy response analyses, gene set variation analysis (GSVA), and GSEA to explore molecular mechanisms and immune landscapes related to the signature and the potential of the signature to predict immunotherapy or chemotherapy response.

Results

First, two LMRG molecular patterns were established, which showed diverse prognoses and immune infiltration statuses. Then, a 12-gene signature was identified, and a risk model was built. The signature remained an independent prognostic parameter in multivariate Cox regression and prognostic meta-analysis. In addition, this signature stratified patients into high- and low-risk groups with significantly different recurrence rates and was well validated in different clinical subgroups and several independent validation cohorts. The results of GO and KEGG analyses and GSEA showed that there were differences in multiple lipid metabolism, immune response, and drug metabolism pathways between the high- and low-risk groups. Further analyses revealed that the signature-based risk model was related to distinct immune cell proportions, immune checkpoint parameters, and immunotherapy and chemotherapy response, consistent with the GO, KEGG, and GSEA results.

Conclusions

This is the first lipid metabolism-based signature for predicting recurrence, and it could provide vital guidance to achieve optimized antitumor for immunotherapy or chemotherapy for early-stage LUAD.

A cytokine in turmoil: Transforming growth factor beta in cancer

Cancer remains one of the debilitating health threats to mankind in view of its incurable nature. Many factors are complicit in the initiation, progression and establishment of cancers. Early detection of cancer is the only window of hope that allows for appreciable management and possible limited survival. However, understanding of cancer biology and knowledge of the key factors that interplay at multi-level in the initiation and progression of cancer may hold possible avenues for cancer treatment and management. In particular, dysregulation of growth factor signaling such as that of transforming growth factor beta (TGF-β) and its downstream mediators play key roles in various cancer subtypes. Expanded understanding of the context/cell type-dependent roles of TGF-β and its downstream signaling mediators in cancer may provide leads for cancer pharmacotherapy. Reliable information contained in original articles, reviews, mini-reviews and expert opinions on TGF-β, cancer and the specific roles of TGF-β signaling in various cancer subtypes were retrieved from major scientific data bases including PubMed, Scopus, Medline, Web of Science core collections just to mention but a sample by using the following search terms: TGF-β in cancer, TGF-β and colorectal cancer, TGF-β and brain cancer, TGF-β in cancer initiation, TGF-β and cell proliferation, TGF-β and cell invasion, and TGF-β-based cancer therapy. Retrieved information and reports were carefully examined, contextualized and synchronized into a coherent scientific content to highlight the multiple roles of TGF-β signaling in normal and cancerous cells. From a conceptual standpoint, development of pharmacologically active agents that exert non-specific inhibitory effects on TGF-β signaling on various cell types will undoubtedly lead to a plethora of serious side effects in view of the multi-functionality and pleiotropic nature of TGF-β. Such non-specific targeting of TGF-β could derail any beneficial therapeutic intention associated with TGF-β-based therapy. However, development of pharmacologically active agents designed specifically to target TGF-β signaling in cancer cells may improve cancer pharmacotherapy. Similarly, specific targeting of downstream mediators of TGF-β such as TGF-β type 1 and II receptors (TβRI and TβRII), receptor-mediated Smads, mitogen activated protein kinase (MAPK) and importing proteins in cancer cells may be crucial for cancer pharmacotherapy.

The role of FHL2 in wound healing and inflammation

The 4-and-a-half LIM domain protein 2 (FHL2) is a multifunctional adaptor protein that can interact with cell surface receptors, cytosolic adaptor and structural proteins, kinases, and nuclear transcription factors. It is involved in numerous functional activities, including the epithelial-mesenchymal transition, cell proliferation, apoptosis, adhesion, migration, structural stability, and gene expression. Despite this, FHL2-knockout (KO) mice are viable and fertile with no obvious abnormalities, rather suggesting a high capacity for fine-tuning adjustment and functional redundancy of FHL2. Indeed, challenging FHL2-KO cells or mice provided numerous evidences for the great functional significance of FHL2. In recent years, several reviews have been published describing the high capacity of FHL2 to bind diverse proteins as well as the versatile functions of FHL2, emphasizing in particular its role in cardiovascular diseases and carcinogenesis. Here, we view the function of FHL2 from a different perspective. We summarize the published data demonstrating the impact of FHL2 on wound healing and inflammation. FHL2 seems to be involved in numerous steps of these extremely complex and multidirectional but tightly regulated tissue remodeling processes, supporting tissue repair and coordinating inflammation. Deficiency of FHL2 not only slows down ongoing wound healing but also often turns it into a chronic condition.-Wixler, V. The role of FHL2 in wound healing and inflammation.

FHL2 interacts with iASPP and impacts the biological functions of leukemia cells

iASPP is an inhibitory member of apoptosis-stimulating proteins of p53 (ASPP) family, which inhibits p53-dependent apoptosis. iASPP was highly expressed in acute leukemia, inhibited leukemia cells apoptosis and promoted leukemogenesis. In order to clarify its mechanism, a yeast two-hybrid screen was performed and FHL2 was identified for the first time as one of the binding proteins of iASPP. FHL2 was highly expressed in K562 and Kasumi-1 cells. FHL2 and iASPP interacted with each other and co-localized in both nucleus and cytoplasm. Either FHL2 or iASPP silenced could reduce cell proliferation, induce cell cycle arrest at G0/G1 phase, and increase cell apoptosis. Western blot analysis showed that the level of p21 and p27 increased, CDK4, E2F1, Cyclin E and anti-apoptotic proteins Bcl-2 and Bcl-xL reduced. Interestingly, when FHL2 was knocked down, the protein expression level of iASPP also decreased. Similarly, the expression of FHL2 would reduce when iASPP was silenced. These results indicated that FHL2 might be a novel potential target for acute myelocytic leukemia treatment.

p68 prompts the epithelial-mesenchymal transition in cervical cancer cells by transcriptionally activating the TGF-β1 signaling pathway

Overexpression of p68 has been reported in various types of cancer. However, little study has been conducted on the expression and role of p68 in cervical cancer. Therefore, the present study focuses on the role of p68 in cervical cancer cells, which may elucidate its potential mechanism of cervical cancer progression and shed light on the precision medical treatment of cervical cancer. Firstly, the expression of p68 was analyzed using reverse transcription-quantitative polymerase chain reaction and western blot analysis. The changes to cell morphology were observed using an inverted microscope (XDS-500D; Shanghai Caikon Optical Instrument Co., Ltd., Shanghai, China). Cell migration was determined using an in vitro scratch assay. The present study demonstrated that the mRNA and protein levels of p68 were significantly enhanced in cervical cancer CaSki, HeLa [human papillomavirus (HPV)-18-positive], SiHa (HPV-16-positive) and C-33A (HPV-negative) cell lines compared with the human keratinocyte HaCaT cell line. Overexpression of p68 induced an elongated and spindle-shaped morphology in CaSki cells. Upregulation of p68 increased the expression of α-smooth muscle actin, vimentin and fibronectin however, epithelial marker E-cadherin was significantly decreased. Furthermore, the in vitro scratch assay demonstrated that overexpression of p68 markedly enhanced CaSki cell migration capacity at 24 and 48 h. Knockdown of p68 partially reversed transforming growth factor-β1 (TGF-β1)-induced changes in epithelial-mesenchymal transition (EMT) markers and cell morphological changes. In summary, the present study demonstrated that p68 transcriptionally activated the expression of TGF-β1, thereby prompting EMT in cervical cancer cells.

LIM-Only Protein FHL2 Is a Negative Regulator of Transforming Growth Factor β1 Expression

Transforming growth factor β1 (TGF-β1) is a master cytokine in many biological processes, including tissue homeostasis, epithelial-to-mesenchymal transition, and wound repair. Here, we report that four and a half LIM-only protein 2 (FHL2) is a critical regulator of TGF-β1 expression. Devoid of a DNA-binding domain, FHL2 is a transcriptional cofactor that plays the role of coactivator or corepressor, depending on the cell and promoter contexts. We detected association of FHL2 with the TGF-β1 promoter, which showed higher activity in Fhl2^-/- cells than in wild-type (WT) cells in a reporter assay. Overexpression of FHL2 abrogates the activation of the TGF-β1 promoter, whereas the upregulation of TGF-β1 gene transcription correlates with reduced occupancy of FHL2 on the promoter. Moreover, ablation of FHL2 facilitates recruitment of RNA polymerase II on the TGF-β1 promoter, suggesting that FHL2 may be involved in chromatin remodeling in the control of TGF-β1 gene transcription. Enhanced expression of TGF-β1 mRNA and cytokine was evidenced in the livers of Fhl2^-/- mice. We tested the in vivo impact of Fhl2 loss on hepatic fibrogenesis that involves TGF-β1 activation. Fhl2^-/- mice developed more severe fibrosis than their WT counterparts. These results demonstrate the repressive function of FHL2 on TGF-β1 expression and contribute to the understanding of the TGF-β-mediated fibrogenic response.

Mammalian Actin-binding Protein-1/Hip-55 Interacts with FHL2 and Negatively Regulates Cell Invasion

Mammalian actin-binding protein-1 (mAbp1) is an adaptor protein that binds actin and modulates scission during endocytosis. Recent studies suggest that mAbp1 impairs cell invasion; however, the mechanism for the inhibitory effects of mAbp1 remain unclear. We performed a yeast two-hybrid screen and identified the adaptor protein, FHL2, as a novel binding partner that interacts with the N-terminal actin depolymerizing factor homology domain (ADFH) domain of mAbp1. Here we report that depletion of mAbp1 or ectopic expression of the ADFH domain of mAbp1 increased Rho GTPase signaling and breast cancer cell invasion. Moreover, cell invasion induced by the ADFH domain of mAbp1 required the expression of FHL2. Taken together, our findings show that mAbp1 and FHL2 are novel binding partners that differentially regulate Rho GTPase signaling and MTLn3 breast cancer cell invasion.

Combining TGF-β1 knockdown and miR200c administration to optimize antitumor efficacy of B16F10/GPI-IL-21 vaccine

TGF-β1 secreted abundantly by tumors cells as well as present in the local microenvironment promotes neoplasm invasion and metastasis by triggering the epithelial to mesenchymal transition (EMT). MiR200c has been shown to suppress EMT and to regulate the cellular epithelial and interstitial state conversion, whereas the tumor vaccines are intended to specifically initiate or amplify a host response against evolving tumor cells. Our study aimed at optimizing the antitumor effects of the B16F10/glycosylphosphatidylinositol-interleukin 21 (B16F10/GPI-IL-21) tumor vaccine on melanoma bearing mice by combining the TGF-β1 knockdown and the administration of miR200c agomir. The mice were subcutaneously vaccinated with inactivated B16F10/GPI-IL-21 vaccine and challenged by B16F10 cells transfected with shTGF-β1 (B16F10/shTGF-β1 cells) or B16F10/shTGF-β1 cells with the administration of miR200c agomir. The later combination showed that, when compared with the mice in the control group that received no vaccination, vaccinated mice significantly increased NK and CTL activities, enhanced levels of IFN-γ, and reduced expression of TGF-β1, N-cadherin, Vimentin, Gli1/2, P-Smad2/3 and others involved in promoting expression of EMT-related molecules in tumor areas, and inhibited the melanoma metastasis in lungs and lymph nodes. Altogether, our findings demonstrate that this synergistic anti-cancer regimen effectively induces strong immune response and diminishes the melanoma progression.

The FHL2 regulation in the transcriptional circuitry of human cancers

The Four-and-a-half LIM (FHL)-only protein is a subfamily of protein members under the LIM-only protein family. These proteins are identified by their characteristic four and a half cysteinerich LIM homeodomain. Five members have been categorized into the FHL subfamily, which are FHL1, FHL2, FHL3, FHL4 and activator of CREM in testis (ACT) in human. FHL2 is amongst the most examined members within the family. Fhl2, the gene that code for the protein, is transcriptionally regulated by diverse types of transcription factors, for example, p53, serum response factor (SRF), and specificity protein 1 (Sp1). The expression of FHL2 is found in different tissues and organs and has been reported as a critical participant influencing the wide types of cancer such as breast cancer, gastrointestinal (GI) cancers, liver cancer and prostate cancer. The expression profile of FHL2 appeared to have a significant functional role in the carcinogenesis of these cancers which are mediated by different types of transcription factor including both tumor suppressors and inducers. In this review, we will first describe the molecular network governing FHL2 expression, which focus on the transcription factors conveying FHL2-initiated responses. In the second part, FHL2-linked cancers and the underlying molecular machinery will be discussed. Factors other than transcriptional regulation which may involve the cancer progression such as mutations of fhl2 and posttranslational modifications of the protein will also be mentioned.