Coordinate suppression of Sdpr and Fhl1 expression in tumors of the breast, kidney, and prostate

Overexpression of FHL1 suppresses papillary thyroid cancer proliferation and progression via inhibiting Wnt/β-catenin pathway

PURPOSE

The four and a half LIM domain protein 1 (FHL1) has been found to act as a tumor suppressor in several cancers. However, the clinical and functional significance, as well as underlying molecular mechanisms of FHL1 in papillary thyroid cancer (PTC) are largely unknown.

METHODS

Bioinformatics analyses, qRT-PCR and Western blotting were used to investigate the expression of FHL1 in PTC. Cell proliferation was measured using CCK8, Edu, colony formation, and flow cytometry assays. Cell migration and invasion were examined by wound healing and Transwell assays. qRT-PCR, Western blot, immunofluorescence and Top/Fop reporter assays were performed to assess the underlying mechanisms.

RESULTS

FHL1 expression was significantly downregulated in PTC. FHL1 downregulation negatively correlated with stage, T classification, and N classification of the patients. The downregulation of FHL1 is associated with poor prognosis. Overexpression of FHL1 inhibited PTC cells' proliferation, invasion, migration and Wnt/β-catenin pathway activity. LiCl partially restored the inhibitory effects of FHL1 on aggressive phenotypes and Wnt/β-catenin pathway activity of PTC cells.

CONCLUSION

FHL1 is downregulated in PTC and its expression is associated with better clinical outcomes for patients with the disease. FHL1 acts as a tumor suppressor via, at least partially, suppressing Wnt/β-catenin pathway.

Role of Caveolae family-related proteins in the development of breast cancer

Breast cancer has become the most significant malignant tumor threatening women's lives. Caveolae are concave pits formed by invagination of the plasma membrane that participate in many biological functions of the cell membrane, such as endocytosis, cell membrane assembly, and signal transduction. In recent years, Caveolae family-related proteins have been found to be closely related to the occurrence and development of breast cancer. The proteins associated with the Caveolae family-related include Caveolin (Cav) and Cavins. The Cav proteins include Cav-1, Cav-2 and Cav-3, among which Cav-1 has attracted the most attention as a tumor suppressor and promoting factor affecting the proliferation, apoptosis, migration, invasion and metastasis of breast cancer cells. Cav-2 also has dual functions of inhibiting and promoting cancer and can be expressed in combination with Cav-1 or play a regulatory role alone. Cav-3 has been less studied in breast cancer, and the loss of its expression can form an antitumor microenvironment. Cavins include Cavin-1, Cavin-2, Cavin-3 and Cavin-4. Cavin-1 inhibits Cav-1-induced cell membrane tubule formation, and its specific role in breast cancer remains controversial. Cavin-2 acts as a breast cancer suppressor, inhibiting breast cancer progression by blocking the transforming growth factor (TGF-β) signaling pathway. Cavin-3 plays an anticancer role in breast cancer, but its specific mechanism of action is still unclear. The relationship between Cavin-4 and breast cancer is unclear. In this paper, the role of Caveolae family-related proteins in the occurrence and development of breast cancer and their related mechanisms are discussed in detail to provide evidence supporting the further study of Caveolae family-related proteins as potential targets for the diagnosis and treatment of breast cancer.

SGLT2 inhibitors improve kidney function and morphology by regulating renal metabolic reprogramming in mice with diabetic kidney disease

Diabetic kidney disease (DKD) is the leading cause of end-stage renal disease (ESRD) worldwide. SGLT2 inhibitors are clinically effective in halting DKD progression. However, the underlying mechanisms remain unclear. The serum and kidneys of mice with DKD were analyzed using liquid chromatography with tandem mass spectrometry (LC–MS/MS)-based metabolomic and proteomic analyses. Three groups were established: placebo-treated littermate db/m mice, placebo-treated db/db mice and EMPA-treated db/db mice. Empagliflozin (EMPA) and placebo (10 mg/kg/d) were administered for 12 weeks. EMPA treatment decreased Cys-C and urinary albumin excretion compared with placebo by 78.60% and 57.12%, respectively (p < 0.001 in all cases). Renal glomerular area, interstitial fibrosis and glomerulosclerosis were decreased by 16.47%, 68.50% and 62.82%, respectively (p < 0.05 in all cases). Multi-omic analysis revealed that EMPA treatment altered the protein and metabolic profiles in the db/db group, including 32 renal proteins, 51 serum proteins, 94 renal metabolites and 37 serum metabolites. Five EMPA-related metabolic pathways were identified by integrating proteomic and metabolomic analyses, which are involved in renal purine metabolism; pyrimidine metabolism; tryptophan metabolism; nicotinate and nicotinamide metabolism, and glycine, serine and threonine metabolism in serum. In conclusion, this study demonstrated metabolic reprogramming in mice with DKD. EMPA treatment improved kidney function and morphology by regulating metabolic reprogramming, including regulation of renal reductive stress, alleviation of mitochondrial dysfunction and reduction in renal oxidative stress reaction.

Heterocellular N-cadherin junctions enable nontransformed cells to inhibit the growth of adjacent transformed cells

BACKGROUND

The Src tyrosine kinase phosphorylates effector proteins to induce expression of the podoplanin (PDPN) receptor in order to promote tumor progression. However, nontransformed cells can normalize the growth and morphology of neighboring transformed cells. Transformed cells must escape this process, called "contact normalization", to become invasive and malignant. Contact normalization requires junctional communication between transformed and nontransformed cells. However, specific junctions that mediate this process have not been defined. This study aimed to identify junctional proteins required for contact normalization.

METHODS

Src transformed cells and oral squamous cell carcinoma cells were cultured with nontransformed cells. Formation of heterocellular adherens junctions between transformed and nontransformed cells was visualized by fluorescent microscopy. CRISPR technology was used to produce cadherin deficient and cadherin competent nontransformed cells to determine the requirement for adherens junctions during contact normalization. Contact normalization of transformed cells cultured with cadherin deficient or cadherin competent nontransformed cells was analyzed by growth assays, immunofluorescence, western blotting, and RNA-seq. In addition, Src transformed cells expressing PDPN under a constitutively active exogenous promoter were used to examine the ability of PDPN to override contact normalization.

RESULTS

We found that N-cadherin (N-Cdh) appeared to mediate contact normalization. Cadherin competent cells that expressed N-Cdh inhibited the growth of neighboring transformed cells in culture, while cadherin deficient cells failed to inhibit the growth of these cells. Results from RNA-seq analysis indicate that about 10% of the transcripts affected by contact normalization relied on cadherin mediated communication, and this set of genes includes PDPN. In contrast, cadherin deficient cells failed to inhibit PDPN expression or normalize the growth of adjacent transformed cells. These data indicate that nontransformed cells formed heterocellular cadherin junctions to inhibit PDPN expression in adjacent transformed cells. Moreover, we found that PDPN enabled transformed cells to override the effects of contact normalization in the face of continued N-Cdh expression. Cadherin competent cells failed to normalize the growth of transformed cells expressing PDPN under a constitutively active exogenous promoter.

CONCLUSIONS

Nontransformed cells form cadherin junctions with adjacent transformed cells to decrease PDPN expression in order to inhibit tumor cell proliferation. Cancer begins when a single cell acquires changes that enables them to form tumors. During these beginning stages of cancer development, normal cells surround and directly contact the cancer cell to prevent tumor formation and inhibit cancer progression. This process is called contact normalization. Cancer cells must break free from contact normalization to progress into a malignant cancer. Contact normalization is a widespread and powerful process; however, not much is known about the mechanisms involved in this process. This work identifies proteins required to form contacts between normal cells and cancer cells, and explores pathways by which cancer cells override contact normalization to progress into malignant cancers. Video Abstract.

FHL1 Inhibits the Progression of Colorectal Cancer by Regulating the Wnt/β-Catenin Signaling Pathway

Purpose: This study aims to explore the FHL1 expression level in colorectal cancer (CRC) patients, analyze its association with patient survival and investigate the role of FHL1 in CRC. Methods: We used secondary sequencing to profile mRNA expression in CRC tissue and corresponding adjacent normal tissue from four CRC patients. We focus on FHL1 and analyzed the association between its expression level and clinical indicators. Furthermore, we explored the functional role of FHL1 in colorectal cancer tumorigenesis by transfecting cells with siRNA or overexpression plasmids. Results: Hierarchical clustering revealed significantly differentially expressed mRNAs. FHL1 expression was significantly lower in CRC tissue than in adjacent normal tissue as well as in CRC cell lines relative to NCM460. Low FHL1 expression in CRC tissue correlated with poor patient survival. Our data demonstrated that overexpression of FHL1 inhibited the proliferation, colony formation potential, and expression of CdK4 and Cyclin D1, whereas ablating FHL1 promoted their proliferation and colony formation potential, suggesting that FHL1 acts as a tumor suppressor in CRC. Moreover, we showed that FHL1 inhibited the proliferation of colorectal cancer cells by negatively regulating the Wnt/β-catenin signaling pathway. Conclusion: FHL1 is a potential tumor suppressor gene in colorectal cancer, and regulation of the FHL1-Wnt/β-catenin pathway may be part of its antitumor mechanism.

Serum deprivation-response protein induces apoptosis in hepatocellular carcinoma through ASK1-JNK/p38 MAPK pathways

Serum deprivation-response protein (SDPR), a phosphatidylserine-binding protein, which is known to have a promising role in caveolar biogenesis and morphology. However, its function in hepatocellular carcinoma (HCC) was still largely unknown. In this study, we discussed the characterization and identification of SDPR, and to present it as a novel apoptosis candidate in the incidence of HCC. We identified 81 HCC cases with lower SDPR expression in the tumor tissues with the help of qRT-PCR assay, and lower SDPR expression was potentially associated with poor prognostication. The phenotypic assays revealed that cell proliferation, invasion, and migration were profoundly connected with SDPR, both in vivo and in vitro. The data obtained from the gene set enrichment analysis (GSEA) carried out on the liver hepatocellular carcinoma (LIHC), and also The Cancer Genome Atlas (TCGA) findings indicated that SDPR was involved in apoptosis and flow cytometry experiments further confirmed this. Furthermore, we identified the interaction between SDPR and apoptosis signal-regulating kinase 1 (ASK1), which facilitated the ASK1 N-terminus-mediated dimerization and increased ASK1-mediated signaling, thereby activating the JNK/p38 mitogen-activated protein kinases (MAPKs) and finally enhanced cell apoptosis. Overall, this work identified SDPR as a tumor suppressor, because it promoted apoptosis by activating ASK1-JNK/p38 MAPK pathways in HCC.

Targeting regulation of the tumour microenvironment induces apoptosis of breast cancer cells by an affinity hemoperfusion adsorbent

The cytokine network of tumour microenvironment (TME) plays an important role in cancer growth and progression. The current work aims to provide a new strategy for cancer therapy based on the targeted regulation of cytokines in the TME. Here, heparin-coupled polyvinyl alcohol (PVA-H) microspheres have been developed as an adsorbent for selectively remove tumour-induced immunosuppressive cytokines, such as vascular endothelial growth factor (VEGF) and transforming growth factor-beta (TGF-β), but not tumour necrosis factor-alpha (TNF-α) which has an immune-stimulating effect and can inhibit tumour growth. The proliferation and apoptosis of breast cancer cells after perfusion were tested by cell viability assays, flow cytometry analysis and mRNA microarray assays. Results showed that the PVA-H microspheres efficiently absorbed the majority of VEGF (74.39%) and TGF-β (86.39%), but much less TNF-α (4.16%). The regulation of the cytokines had remarkable anti-proliferative and pro-apoptotic effects on breast cancer cells, which was further confirmed from the change of mRNA expression levels. Thus, targeting regulatory pathways within the TME by an affinity adsorbent that selectively depletes immunosuppressive cytokines is potentially a new and promising strategy for cancer therapy.

Caveola-forming proteins and prostate cancer

Caveolae are specialised and dynamic plasma membrane subdomains, involved in many cellular functions including endocytosis, signal transduction, mechanosensing and lipid storage, trafficking, and metabolism. Two protein families are indispensable for caveola formation and function, namely caveolins and cavins. Mutations of genes encoding these caveolar proteins cause serious pathological conditions such as cardiomyopathies, skeletal muscle diseases, and lipodystrophies. Deregulation of caveola-forming protein expression is associated with many types of cancers including prostate cancer. The distinct function of secretion of the prostatic fluid, and the unique metabolic phenotype of prostate cells relying on lipid metabolism as a main bioenergetic pathway further suggest a significant role of caveolae and caveolar proteins in prostate malignancy. Accumulating in vitro, in vivo, and clinical evidence showed the association of caveolin-1 with prostate cancer grade, stage, metastasis, and drug resistance. In contrast, cavin-1 was found to exhibit tumour suppressive roles. Studies on prostate cancer were the first to show the distinct function of the caveolar proteins depending on their localisation within the caveolar compartment or as cytoplasmic or secreted proteins. In this review, we summarise the roles of caveola-forming proteins in prostate cancer and the potential of exploiting them as therapeutic targets or biological markers.

The Transcriptomic Landscape of Prostate Cancer Development and Progression: An Integrative Analysis

Next-generation sequencing of primary tumors is now standard for transcriptomic studies, but microarray-based data still constitute the majority of available information on other clinically valuable samples, including archive material. Using prostate cancer (PC) as a model, we developed a robust analytical framework to integrate data across different technical platforms and disease subtypes to connect distinct disease stages and reveal potentially relevant genes not identifiable from single studies alone. We reconstructed the molecular profile of PC to yield the first comprehensive insight into its development, by tracking changes in mRNA levels from normal prostate to high-grade prostatic intraepithelial neoplasia, and metastatic disease. A total of nine previously unreported stage-specific candidate genes with prognostic significance were also found. Here, we integrate gene expression data from disparate sample types, disease stages and technical platforms into one coherent whole, to give a global view of the expression changes associated with the development and progression of PC from normal tissue through to metastatic disease. Summary and individual data are available online at the Prostate Integrative Expression Database (PIXdb), a user-friendly interface designed for clinicians and laboratory researchers to facilitate translational research.

LINC00261/microRNA-550a-3p/SDPR axis affects the biological characteristics of breast cancer stem cells

Long non-coding RNAs (lncRNAs) have been shown to play key roles in the pathogenesis of breast cancer (BC). The study was to explore the effect of long non-coding RNA LINC00261/microRNA (miR)-550a-3p/serum deprivation response (SDPR) axis on the biological characteristics of BC stem cells (BCSCs). BC and adjacent normal tissues of patients were collected. LINC00261, miR-550a-3p and SDPR expression in BC tissues and cell lines and CD24 and CD44 expression in BC tissues was detected. CD44⁺ /CD24^-/low BCSCs were sorted. CD44⁺ /CD24^-/low MDA-MB-231 and MCF-7 cells were screened and transfected with altered expression of LINC00261 or miR-550a-3p to explore their roles in cell viability, microsphere (MS) formation ability, migration and invasion of CD44⁺ /CD24^-/low BCSCs. The targeting relationships of LINC00261, miR-550a-3p and SDPR were detected. Reduced LINC00261, decreased SDPR and elevated miR-550a-3p exhibited in BC tissues of patients and cell lines. Elevated CD44^+/ CD24^- were present in BC tissues. LINC00261 up-regulated SDPR expression as a sponge of miR-550a-3p. Elevated LINC00261 suppressed BC cell viability, MS formation ability, migration and invasion of CD44⁺ /CD24^-/low BCSCs. Moreover, up-regulated miR-550a-3p reversed the inhibitive effect of elevated LINC00261 on BCSCs, and reduced SDPR reversed the promotive effect of decreased miR-550a-3p on BCSCs. The study highlights that LINC00261 can adsorb miR-550a-3p to modulate SDPR, thus inhibiting the viability and MS formation of BC cells, reducing migration and invasion of CD44⁺ /CD24^-/low BCSCs, exerting a potential effect on therapy.

FHL1 promotes glioblastoma aggressiveness through regulating EGFR expression

The four-and-a-half LIM domain protein 1 (FHL1) plays a key role in multiple cancers. Here, we characterized its role in glioblastoma (GBM), the most common and incurable form of brain cancer. Overexpression of FHL1 promotes growth, migration, and invasion of GBM cells in vivo and in vitro. In contrast, FHL1 silencing by RNAi exhibits the opposite effects. FHL1 interacts with the transcription factor SP1 to upregulate epidermal growth factor receptor (EGFR) expression and activate the downstream signaling cascades, including Src, Akt, Erk1/2, and Stat3, leading to GBM malignancy. FHL1 is highly expressed and positively correlated with EGFR levels in human GBM, particularly those of the classical subtype. Our results suggest that the FHL1-SP1-EGFR axis plays a tumor-promoting role, and highlight the translational potential of inhibiting FHL1 for GBM treatment.

Identification of a novel prognostic DNA methylation signature for lung adenocarcinoma based on consensus clustering method

Abnormal DNA methylation persists throughout carcinogenesis and cancer development. Hence, gene promoter methylation may act as a prognostic tool and provide new potential therapeutic targets for patients with lung adenocarcinoma (LUAD). In this study, to explore prognostic methylation signature, data regarding DNA methylation and RNA-seq, and clinical data of patients with LUAD from the Cancer Genome Atlas database (TCGA) were downloaded. After data preprocessing, the methylation data were divided into training (N = 405) and test sets (N = 62). Then, patients in the training set were assigned to five subgroups based on their different methylation levels using the consensus clustering method. We comprehensively analyzed the survival information, methylation levels, and clinical variables, including American Joint Committee on Cancer (AJCC) stage, tumor-node-metastasis (TNM) staging, age, smoking history, and gender of these five groups. Subsequently, we identified a 16-CpG prognostic signature and constructed a prognostic model, which was verified in the test set. Further analyses showed stable prognostic performance in the stratified cohorts. In conclusion, the new predictive DNA methylation signature proposed in this study may be used as an independent biomarker to assess the overall survival of LUAD patients and provide bioinformatics information for development of targeted therapy.

Four and a half LIM domains protein 1 can be as a double-edged sword in cancer progression

Four and a half LIM domains protein 1 (FHL1), as the name suggests, contains four and a half LIM domains capable of interacting with various molecules, including structural proteins, kinases, and transcriptional machinery. FHL1 contains a zinc-finger domain and performs diverse roles in regulation of gene transcription, cytoarchitecture, cell proliferation, and signal transduction. Several studies have validated the importance of FHL1 in muscle development, myopathy, and cardiovascular diseases. Mutations in the FHL1 gene are associated with various myopathies. Recently, FHL1 was identified as a major host factor for chikungunya virus (CHIKV) infection in both humans and mice. Based on more recent findings over the last decade, FHL1 is proposed to play a dual role in cancer progression. On the one hand, FHL1 expression is suppressed in several cancer types, which correlates with increased metastatic disease and decreased survival. Moreover, FHL1 is reported to inhibit tumor cell growth and migration by associating with diverse signals, such as TGF-β and ER, and therefore considered a tumor suppressor. On the other hand, FHL1 can function as an oncogenic protein that promotes tumor progression upon phosphorylation, reflecting complex roles in cancer. This review primarily focuses on the dual role and underlying mechanisms of action of FHL1 in human cancer progression and its clinical relevance.

Downregulation of FHL1 protein in glioma inhibits tumor growth through PI3K/AKT signaling

Human four-and-a-half LIM domains protein 1 (FHL1) is a member of the FHL protein family, which serves an important role in multiple cellular events by interacting with transcription factors using its cysteine-rich zinc finger motifs. A previous study indicated that FHL1 was downregulated in several types of human cancer and served a role as a tumor suppressive gene. The overexpression of FHL1 inhibited tumor cell proliferation. However, to the best of our knowledge, there is no evidence to confirm whether FHL1 affected glioma growth, and the molecular mechanisms through which FHL1 represses tumor development remain unclear. In the present study, the expression level of FHL1 was determined using immunohistochemical staining in 114 tumor specimens from patients with glioma. The results indicated that FHL1 expression was negatively associated with the pathological grade of gliomas. Furthermore, Kaplan-Meier survival curves demonstrated that the patients with an increased FHL1 expression exhibited a significantly longer survival time, suggesting that FHL1 may be a prognostic marker for glioma. The protein level of FHL1 was relatively increased in the U251 glioma cell line compared with that in the U87 cell line. Therefore, FHL1 was knocked down in U251 by siRNA and overexpressed in U87, and it was identified that FHL1 significantly decreased the activation of PI3K/AKT signaling by interacting with AKT. Further experiments verified that FHL1 inhibited the growth of gliomas in vivo by modulating PI3K/AKT signaling. In conclusion, the results of the present study demonstrated that FHL1 suppressed glioma development through PI3K/AKT signaling.

Prognostic and diagnostic significance of Cavin 2 in lung adenocarcinoma

INTRODUCTION

Cavin 2 down-regulation is reported in several malignant tumors and is associated with tumor progression. However, the role of Cavin 2 in lung adenocarcinoma is unknown. This study aimed to investigate the prognostic and diagnostic significance of Cavin 2 in lung adenocarcinoma.

MATERIAL AND METHODS

Cavin 2 expression levels were examined in 150 cases of lung adenocarcinoma and matched adjacent normal lung tissues using RNA extraction and reverse transcription-quantitative polymerase chain reaction (RT-qPCR), Western blotting and immunohistochemistry (IHC) assays. Then, the relationship of Cavin 2 expression with clinicopathological characteristics and patients' survival was further evaluated in lung adenocarcinoma.

RESULTS

QPCR and Western blotting analysis indicated that Cavin 2 expression levels were significantly lower in lung adenocarcinoma tissues compared with those in adjacent normal lung tissues (p < 0.0001). The IHC results showed that positive expression of Cavin 2 was mainly located in cytoplasm as brown, but was hard to detect in lung adenocarcinoma tissues. The low-expression rates of Cavin 2 in lung adenocarcinoma and adjacent normal lung tissues were 62.0% and 20.0%, respectively, and the difference was significant (p < 0.0001). Lower expression of Cavin 2 was significantly associated with tumor size, TNM stage and lymph node metastasis (p < 0.05).

CONCLUSIONS

Cavin 2 has low expression in lung adenocarcinoma, which might be regarded as a potential prognostic and diagnostic biomarker.

Long Intergenic Noncoding RNA 00261 Acts as a Tumor Suppressor in Non-Small Cell Lung Cancer via Regulating miR-105/FHL1 Axis

Purpose: Long noncoding RNAs (lncRNAs) have recently received more attention for their roles in tumor progression. LINC00261 was studied in this research to identify how it affects the progression of non-small cell lung cancer (NSCLC).

Methods: Firstly, the expression of LINC00261 in NSCLC cells and paired samples of NSCLC tissue was detected by RT-qPCR. Then, the associations between LINC00261 expression level and clinicopathological characteristics were evaluated. Furthermore, functional assays of cell proliferation, colony formation and transwell, as well as western blot assay, luciferase assay and RNA immunoprecipitation (RIP) assay were conducted. Afterwards, the effects of LINC00261 expression on NSCLC formation and growing were confirmed by in vivo models.

Results: As results, expression of LINC00261 was significantly down-regulated in tumor samples than that in normal samples, which was correlated with the lymphatic metastasis, tumor size, tumor stage as well as patient survival time. Knockdown of LINC00261 inhibited tumor growth and invasion ability in vitro. In addition, miR-105 was identified as a direct target of LINC00261 via mechanism experiments and its expression in tumor tissues negatively correlated to LINC00261 expression. Further experiments found that Four and expression of Half LIM domains 1 (FHL1) was negatively correlated with miR-105 but positively with LINC00261. Moreover, in vivo assays verified the overexpression of LINC00261 could suppress formation of NSCLC and regulate the expression of miR-105/FHL1 axis.

Conclusions: These results indicate that LINC00261 could suppress metastasis and proliferation of NSCLC via suppressing miR-105/FHL1 axis, which may offer a new vision for interpreting the mechanism of NSCLC development.

Serum deprivation-response protein regulates aldehyde dehydrogenase 1 through integrin-linked kinase signaling in endometrioid carcinoma cells

Endometrioid carcinoma (EC) is one of the most common malignancies of the female genital system. We reported previously that aldehyde dehydrogenase 1 (ALDH1), a predominant isoform of the ALDH family in mammals and a potential marker of normal and malignant stem cells, is related to the tumorigenic potential of EC. We compared the levels of various proteins in human EC cells with high and low ALDH1 expression using shotgun proteomics and found that serum deprivation‐response protein (SDPR) was preferentially expressed in cells with high ALDH1 expression. Also known as cavin‐2, SDPR is a member of the cavin protein family, which is required for the formation of caveolae. Using SDPR‐knockout EC cells generated using the CRISPR/Cas9 system, we revealed that SDPR was correlated with invasion, migration, epithelial‐mesenchymal transition, and colony formation, as well as the expression of ALDH1. RNA sequencing showed that integrin‐linked kinase (ILK) signaling is involved in the effect of SDPR on ALDH1. Immunohistochemical analysis revealed that the localization of ILK at the cell cortex was disrupted by SDPR knockout, potentially interfering with ILK signaling. Moreover, immunohistochemical analysis of clinical samples showed that SDPR is related to histological characteristics associated with invasiveness, such as poor differentiation, lymphatic invasion, and the microcystic, elongated, and fragmented histopathological pattern. This is, to our knowledge, the first report that SDPR is related to tumor progression.

miR-577 Regulates TGF-β Induced Cancer Progression through a SDPR-Modulated Positive-Feedback Loop with ERK-NF-κB in Gastric Cancer

Transforming growth factor β (TGF-β) drives epithelial-mesenchymal transition (EMT), playing vital roles in cancer metastasis. The crosstalk between microRNAs (miRNAs) and TGF-β are frequently observed and involved in TGF-β-induced EMT. Here, we determine that miR-577 is significantly upregulated in gastric cancer (GC). miR-577 expression is positively correlated with GC metastasis status and poor patient prognosis. Functional assays demonstrate that miR-577 promotes metastasis and chemoresistance by inducing EMT and stemness-like properties. Moreover, TGF-β promotes the expression of miR-577, and miR-577 participates TGF-β-mediated cancer metastasis. Mechanistically, TGF-β activates miR-577 via NF-κB-mediated transcription, and miR-577 enhances TGF-β signaling by targeting the serum deprivation protein response (SDPR), which directly interacts with ERK to inactivate the ERK-NF-κB pathway, hence forming a feedback loop to drive tumor metastasis. A plausible mechanism of EMT induction by the TGF-β network is elucidated. Our findings suggest that the TGF-β-miR-577-SDPR axis may be a potential prognostic marker and therapeutic target against cancer metastasis in GC.

Overexpression Of hsa-miR-664a-3p Is Associated With Cigarette Smoke-Induced Chronic Obstructive Pulmonary Disease Via Targeting FHL1

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is recognized as a chronic lung disease with incomplete reversible airflow limitation, but its pathophysiology was still not clear. This study aimed at investigating regulatory roles of special miRNA-mRNA axis in COPD development.

METHODS

Differentially expressed miRNAs and downstream mRNAs were screened from the Gene Expression Omnibus (GEO) dataset by using the LIMMA package in R software. Weighted Gene Co-expression Network Analysis (WGCNA) was used to construct a co-expression network for COPD. The correlation of dysregulated miRNA(s) and COPD was analyzed, and miRNAs with significant differences were validated in peripheral blood mononuclear cells (PBMCs) from COPD patients by real-time PCR. Regulatory roles of candidate miRNAs and targeted mRNAs were investigated in vitro study.

RESULTS

Thirteen modules of co-expressed miRNAs and mRNAs were constructed from a selected cohort with WGCNA. Turquoise module with 12 differentially expressed miRNAs and 120 mRNAs was significantly correlated with COPD. The expression of hsa-miR-664a-3p, an upregulated miRNA in the module, was increased both in lung tissue and PBMCs from COPD patients, whereas that targeted four and a half LIM domains 1 (FHL1) gene was decreased and positively correlated with forced expiratory volume in 1 sec (FEV1)/forced vital capacity (FVC%) (r = 0.59, p < 0.01). In vitro, luciferase activity assay revealed FHL1 as a target of hsa-miR-664a-3p and it could be directly downregulated by overexpression of hsa-miR-664a-3p. Furthermore, cigarette smoke extract could increase hsa-miR-664a-3p level and decrease FHL1 level in Beas-2B cells.

CONCLUSION

The present study validated significant upregulation of hsa-miR-664a-3p in COPD patients, and its target gene FHL1 was downregulated and positively correlated with FEV1/FVC%; both hsa-miR-664a-3p and FHL1 could be regulated by cigarette smoke extract. Results of bioinformatic analyses and expanded validation suggest that the axis from hsa-miR-664a-3p to FHL1 might play a key role in cigarette smoke-induced COPD, and the exact mechanism should be confirmed in further studies.

IGF2-derived miR-483-3p associated with Hirschsprung's disease by targeting FHL1

HSCR (Hirschsprung's disease) is a serious congenital defect, and the aetiology of it remains unclear. Many studies have highlighted the significant roles of intronic miRNAs and their host genes in various disease, few was mentioned in HSCR although. In this study, miR-483-3p along with its host gene IGF2 (Insulin-like growth factor 2) was found down-regulated in 60 HSCR aganglionic colon tissues compared with 60 normal controls. FHL1 (Four and a half LIM domains 1) was determined as a target gene of miR-483-3p via dual-luciferase reporter assay, and its expression was at a higher level in HSCR tissues. Here, we study cell migration and proliferation in human 293T and SH-SY5Y cell lines by performing Transwell and CCK8 assays. In conclusion, the knockdown of miR-483-3p and IGF2 both suppressed cell migration and proliferation, while the loss of FHL1 leads to opposite outcome. Furthermore, miR-483-3p mimics could rescue the negative effects on cell proliferation and migration caused by silencing IGF2, while the FHL1 siRNA may inverse the function of miR-483-3p inhibitor. This study revealed that miR-483-3p derived from IGF2 was associated with Hirschsprung's disease by targeting FHL1 and may provide a new pathway to understand the aetiology of HSCR.

Podoplanin emerges as a functionally relevant oral cancer biomarker and therapeutic target

Oral cancer has become one of the most aggressive types of cancer, killing 140,000 people worldwide every year. Current treatments for oral cancer include surgery and radiation therapies. These procedures can be very effective; however, they can also drastically decrease the quality of life for survivors. New chemotherapeutic treatments are needed to more effectively combat oral cancer. The transmembrane receptor podoplanin (PDPN) has emerged as a functionally relevant oral cancer biomarker and chemotherapeutic target. PDPN expression promotes tumor cell migration leading to oral cancer invasion and metastasis. Here, we describe the role of PDPN in oral squamous cell carcinoma progression, and how it may be exploited to prevent and treat oral cancer.

Src-mediated phosphorylation converts FHL1 from tumor suppressor to tumor promoter

FHL1 has been recognized for a long time as a tumor suppressor protein that associates with both the actin cytoskeleton and the transcriptional machinery. We present in this study a paradigm that phosphorylated FHL1 functions as an oncogenic protein by promoting tumor cell proliferation. The cytosolic tyrosine kinase Src interacts with and phosphorylates FHL1 at Y149 and Y272, which switches FHL1 from a tumor suppressor to a cell growth accelerator. Phosphorylated FHL1 translocates into the nucleus, where it binds to the transcription factor BCLAF1 and promotes tumor cell growth. Importantly, the phosphorylation of FHL1 is increased in tissues from lung adenocarcinoma patients despite the down-regulation of total FHL1 expression. Kindlin-2 was found to interact with FHL1 and recruit FHL1 to focal adhesions. Kindlin-2 competes with Src for binding to FHL1 and suppresses Src-mediated FHL1 phosphorylation. Collectively, we demonstrate that FHL1 can either suppress or promote tumor cell growth depending on the status of the sites for phosphorylation by Src.

A six-gene panel to label follicular adenoma, low- and high-risk follicular thyroid carcinoma

The distinction between follicular thyroid carcinomas (FTCs) and follicular-patterned benign lesions is almost impossible on fine-needle aspiration cytology. Furthermore, minimally invasive FTCs (MI-FTCs) with less than 4 vascular invasion foci generally have an excellent prognosis, but there are exceptions and, so far, no molecular marker appears able to identify them reliably. We aimed to distinguish benign lesions from low- and high-risk FTCs by a small-scale combination of genes. The expression analysis of 75 selected genes was performed on 18 follicular adenomas (FAs), 14 MI-FTCs and 6 widely invasive FTC (WI-FTCs). The mutational status of the RAS genes, TERT promoter and PAX8-PPARG rearrangements was also investigated. Seven samples were mutated, namely 3 MI-FTCs and 4 WI-FTCs. Twenty-five genes were differentially expressed (FDR <0.05) between FAs and WI-FTCs. Six of these (ECM1, RXRG, SDPR, SLC26A4, TIFF3, TIMP1) were also differently expressed among MI-FTCs and FAs or WI-FTCs and were considered to build a classification model, which was tested to classify samples according to their histological class. Hence, 31 out of 38 were correctly classified, and accuracy remained high after cross-validation (27/38). The 2 MI-FTCs incorrectly classified as WI-FTCs harbored both RAS and TERT promoter mutations. The capability of these six genes to stratify benign, low- and high-risk lesions appears to be promising in supporting the diagnosis of indeterminate thyroid nodules.

Epigenetic analysis of FHL1 tumor suppressor gene in human liver cancer

Liver cancer is one of the most common types of cancer among human malignancies. Four and a half LIM domains 1 (FHL1), as a tumor suppressor gene, is frequently downregulated in multiple types of human cancer. However, the role and specific mechanisms of FHL1 as a tumor suppressor in liver cancer are poorly understood. The present study aimed to investigate the role and associated mechanisms of FHL1 in human liver cancer. The level of FHL1 mRNA in hepatocellular carcinoma (HCC) tissue specimens and cell lines derived from the human liver was determined using reverse transcription polymerase chain reaction and western blot analysis. The association between FHL1 expression and clinicopathological characteristics of patients with liver cancer was analyzed. Western blotting, small interfering RNA (siRNA) and chromatin immunoprecipitation were used to study the expression association of FHL1 and enhancer of zeste homolog 2 (EZH2) in human liver cancer and to explore the regulatory mechanism of FHL1 downregulation. Colony formation and migration assays were performed while FHL1 was overexpressed in Hep3B cells. The results showed that the expression of FHL1 mRNA in tumor tissue decreased, exhibiting a significant difference compared with the adjacent non-cancerous tissue (P<0.05). However, the downregulation of FHL1 was not significantly associated with the sex, age, hepatitis B virus infection status, tumor size, distant metastasis status or level of tumor differentiation of the patients. FHL1 was synergistically silenced by DNA methylation and histone modification, and 3-deanzaneplanocin A (DZNep), an inhibitor of EZH2, which is a histone methyltransferase of the polycomb repressive complex 2, which catalyzes histone H3 lysine 27 tri-methylation (H3K27me3). A significant association between FHL1 and EZH2 expression was identified in the female hepatocellular carcinoma (HCC) samples, but was not in the male HCC samples. FHL1 overexpression and DZNep treatment significantly suppressed the growth and migration of Hep3B cells by restoring FHL1 expression. H3K27me3 was significantly enriched at the FHL1 promoter region, as indicated by a chromatin immunoprecipitation assay, and associated with the epigenetic repression of the FHL1 tumor suppressor gene in HCC cell lines. In conclusion, the present study provides an insight into DNA methylation and EZH2-H3K27me3 epigenetic repression of FHL1 in human liver cancer.

Downregulation of lncRNA SDPR-AS is associated with poor prognosis in renal cell carcinoma

Renal cell carcinoma (RCC) is a common type of kidney cancer. Normally, surgical treatment can prolong life, but only for patients with early stage tumors. However, it is difficult for early detection strategies to distinguish between benign and malignant kidney tumors. Therefore, potential biomarkers for early diagnosis and prognosis of RCC are needed. Intriguingly, mounting evidence has demonstrated that many long noncoding RNAs (lncRNAs) are strongly linked to cancers. Indeed, promising RCC-associated lncRNA biomarkers have also been identified. However, the functional and prognostic roles of the antisense (AS) serum deprivation response (SDPR) lncRNA (SDPR-AS) in RCC remain largely unknown. The aims of this study were to investigate the expression and prognostic relevance of SDPR-AS in RCC. We uncovered the downregulated expressions of both lncRNA SDPR-AS and its protein-coding gene, SDPR, in RCC tissues compared to the matched normal tissues. Furthermore, SDPR-AS and SDPR expressions were positively correlated. Overexpression and knockdown experiments suggested that SDPR-AS and SDPR were coregulated in RCC cell lines. In addition, overexpression of SDPR-AS suppressed cell migration and invasion, but not cell growth. Furthermore, expression of SDPR-AS was associated with tumor differentiation and lymphatic metastasis. Kaplan–Meier survival and log-rank tests demonstrated the association of elevated expression of SDPR-AS with increased overall survival. In conclusion, our results suggest that the SDPR-AS may serve as a prognostic biomarker and therapeutic target of RCC.

A signature motif in LIM proteins mediates binding to checkpoint proteins and increases tumour radiosensitivity

Tumour radiotherapy resistance involves the cell cycle pathway. CDC25 phosphatases are key cell cycle regulators. However, how CDC25 activity is precisely controlled remains largely unknown. Here, we show that LIM domain-containing proteins, such as FHL1, increase inhibitory CDC25 phosphorylation by forming a complex with CHK2 and CDC25, and sequester CDC25 in the cytoplasm by forming another complex with 14-3-3 and CDC25, resulting in increased radioresistance in cancer cells. FHL1 expression, induced by ionizing irradiation in a SP1- and MLL1-dependent manner, positively correlates with radioresistance in cancer patients. We identify a cell-penetrating 11 amino-acid motif within LIM domains (eLIM) that is sufficient for binding CHK2 and CDC25, reducing the CHK2–CDC25 and CDC25–14-3-3 interaction and enhancing CDC25 activity and cancer radiosensitivity accompanied by mitotic catastrophe and apoptosis. Our results provide novel insight into molecular mechanisms underlying CDC25 activity regulation. LIM protein inhibition or use of eLIM may be new strategies for improving tumour radiosensitivity.

CDC25 phosphatases are important cell cycle regulators. Here, the authors show that the LIM domain-containing proteins (for example, FHL1) induce inhibitory CDC25 phosphorylation resulting in radioresistance and that a specific peptide can increase tumour radiosensitivity by increasing CDC25 activity.

X-linked FHL1 as a novel therapeutic target for head and neck squamous cell carcinoma

To identify X-linked novel tumor suppressors could provide novel insights to improve prognostic prediction and therapeutic strategy for some cancers. Using bioinformatics and Venn analysis of gene transcriptional profiling, we identified downregulation of X-linked four-and-a-half LIM domains protein 1 (FHL1) gene in head and neck squamous cell carcinoma (HNSCC). FHL1 functions were investigated and confirmed in vitro and in vivo. FHL1 downregulated mechanisms were analyzed in HNSCCs by using methylation specific PCR, bisulfate-based sequencing, 5-Aza-dC treatment and chromatin immunoprecipitation assays. Two independent HNSCC cohorts (the training cohort n = 105 and the validation cohort n = 101) were enrolled to evaluate clinical implications of FHL1 expression by using real-time PCR or immunohistochemistry. FHL1 mRNA and protein expressions were frequently decreased in HNSCCs. FHL1 overexpression or depletion gave rise to suppress or promote cell growth through Cyclin D1, Cyclin E and p27 dysregulations. Abundant occupy of EZH2 or H3K27Me3 was observed in FHL1 promoter except for DNA hypermethylation. Reduced FHL1 mRNA expression was notably associated with poor differentiation (p = 0.020). Multivariate analysis demonstrated FHL1 mRNA expression was identified as independent prognostic predictors of overall survival (OS) (p = 0.036; HR 0.520; Cl, 0.283-0.958) and disease-free survival (DFS) (p = 0.041; HR 0.527; Cl, 0.284-0.975), which was validated by another independent cohort (p = 0.021; HR 0.404; Cl, 0.187-0.871 for OS; p = 0.011; HR 0.407; Cl, 0.203-0.815 for DFS). These results suggest epigenetic silencing of X-linked FHL1 may have an important role in adjuvant therapeutic intervention of HNSCCs and is an independent prognostic factor in patients with HNSCCs.

Serum deprivation response inhibits breast cancer progression by blocking transforming growth factor-β signaling

Serum deprivation response (SDPR), a key substrate for protein kinase C, play a critical role in inducing membrane curvature and participate in the formation of caveolae. However, the function of SDPR in cancer development and progression is still not clear. Here, we found that SDPR is downregulated in human breast cancer. Overexpression of SDPR suppresses cell proliferation and invasion in MDA‐MB‐231 cells, while depletion of SDPR promotes cell proliferation and invasion in MCF10A cells. Subsequently, SDPR depletion induces epithelial–mesenchymal transition (EMT)‐like phenotype. Finally, knockdown of SDPR activates transforming growth factor‐β (TGF‐β) signaling by upregulation of TGF‐β1 expression. In conclusion, our results showed that SDPR inhibits breast cancer progression by blocking TGF‐β signaling.

Serum deprivation response suppresses cell proliferation and invasion in breast cancer cells. SDPR depletion induces epithelial–mesenchymal transition by activation of TGF‐β signaling.

SDPR functions as a metastasis suppressor in breast cancer by promoting apoptosis

Metastatic dissemination of breast cancer cells represents a significant clinical obstacle to curative therapy. The loss of function of metastasis suppressor genes is a major rate-limiting step in breast cancer progression that prevents the formation of new colonies at distal sites. However, the discovery of new metastasis suppressor genes in breast cancer using genomic efforts has been slow, potentially due to their primary regulation by epigenetic mechanisms. Here, we report the use of model cell lines with the same genetic lineage for the identification of a novel metastasis suppressor gene, serum deprivation response (SDPR), localized to 2q32-33, a region reported to be associated with significant loss of heterozygosity in breast cancer. In silico metaanalysis of publicly available gene expression datasets suggests that the loss of expression of SDPR correlates with significantly reduced distant-metastasis-free and relapse-free survival of breast cancer patients who underwent therapy. Furthermore, we found that stable SDPR overexpression in highly metastatic breast cancer model cell lines inhibited prosurvival pathways, shifted the balance of Bcl-2 family proteins in favor of apoptosis, and decreased migration and intravasation/extravasation potential, with a corresponding drastic suppression of metastatic nodule formation in the lungs of NOD/SCID mice. Moreover, SDPR expression is silenced by promoter DNA methylation, and as such it exemplifies epigenetic regulation of metastatic breast cancer progression. These observations highlight SDPR as a potential prognostic biomarker and a target for future therapeutic applications.

Cavin-2 in oral cancer: A potential predictor for tumor progression

Cavin-2 (CVN2) affects formation of large caveolae, which are membrane-rich cholesterol domains associated with several functions in signal transduction. Accumulating evidence suggests that CVN2 is present in many cellular types; however, the molecular mechanisms of CVN2 in cancers and its clinical relevance are unknown. We proposed a mechanism by which CVN2 regulates caveolin-1 expression leading to slow cellular proliferation by inactivation of the extracellular regulated kinase (ERK) pathway. Quantitative reverse transcriptase-polymerase chain reaction and immunoblot analyses were used to assess the CVN2 regulation mechanism in oral squamous cell carcinoma (OSCC). Immunohistochemistry (IHC) was performed to analyze the correlation between CVN2 expression and clinical behavior in 115 patients with OSCC. A CVN2 overexpressed model of OSCC cells (oeCVN2 cells) was used for functional experiments. CVN2 expression was down-regulated significantly (P < 0.05) in OSCCs compared with normal counterparts in vitro and in vivo. In addition to the findings that a serum deprivation culture induced up-regulation of CVN2 and slowed cellular proliferation, oeCVN2 cell growth decreased because of cell-cycle arrest at the G1 phase resulting from up-regulated cyclin-dependent kinase inhibitors (p21(Cip1) and p27(Kip1) ) and down-regulated cyclins (cyclin D1, cyclin E) and cyclin-dependent kinases (CDK2, CDK4, and CDK6). Interestingly, CVN2 overexpression facilitated caveolin-1 recruitment and colocalization with each other. We also found decreased ERK phosphorylation levels, an upstream event in cell-cycle arrest. Clinically, IHC data from primary OSCCs showed high tumoral progression in CVN2-negative patients with OSCC. CVN2 may be a possible key regulator of OSCC progression via the CVN2/caveolin-1/ERK pathway and a potential therapeutic target for developing new treatments for OSCCs. © 2015 Wiley Periodicals, Inc.

FHL1 inhibits the growth of tongue squamous cell carcinoma cells via G1/S cell cycle arrest

Four and a half LIM protein 1 (FHL1) has been characterized as a tumor suppressor in various types of tumor. However, the biological function and underlying mechanism of FHL1 in tongue squamous cell carcinoma (TSCC) remain to be elucidated. The present study demonstrated that FHL1 inhibits anchorage‑dependent and ‑independent growth of TSCC cells in vitro and tumor growth in nude mice, as determined by cell proliferation and soft agar assays. Knockdown of FHL1 with FHL1 small interfering RNA (siRNA) promoted tumor growth in nude mice. Mechanistically, flow cytometric analysis showed that knockdown of FHL1 promoted G1/S cell cycle progression. Furthermore, expression of cell cycle‑associated regulators, cyclin D and cyclin E, were detected by western blotting and reverse transcription‑quantitative polymerase chain reaction. Cyclin D and cyclin E were markedly elevated at both the protein and mRNA level in the FHL1 siRNA‑transfected cells. These results suggested that FHL1 has a tumor suppressive role in TSCC and that FHL1 may be a useful target for TSCC gene therapy.

Antibody and lectin target podoplanin to inhibit oral squamous carcinoma cell migration and viability by distinct mechanisms

Podoplanin (PDPN) is a unique transmembrane receptor that promotes tumor cell motility. Indeed, PDPN may serve as a chemotherapeutic target for primary and metastatic cancer cells, particularly oral squamous cell carcinoma (OSCC) cells that cause most oral cancers. Here, we studied how a monoclonal antibody (NZ-1) and lectin (MASL) that target PDPN affect human OSCC cell motility and viability. Both reagents inhibited the migration of PDPN expressing OSCC cells at nanomolar concentrations before inhibiting cell viability at micromolar concentrations. In addition, both reagents induced mitochondrial membrane permeability transition to kill OSCC cells that express PDPN by caspase independent nonapoptotic necrosis. Furthermore, MASL displayed a surprisingly robust ability to target PDPN on OSCC cells within minutes of exposure, and significantly inhibited human OSCC dissemination in zebrafish embryos. Moreover, we report that human OSCC cells formed tumors that expressed PDPN in mice, and induced PDPN expression in infiltrating host murine cancer associated fibroblasts. Taken together, these data suggest that antibodies and lectins may be utilized to combat OSCC and other cancers that express PDPN.

MiR-410 is overexpressed in liver and colorectal tumors and enhances tumor cell growth by silencing FHL1 via a direct/indirect mechanism

FHL1 is an important tumor-suppressor that is downregulated in multiple tumors by unknown mechanisms. We demonstrated that miR-410 specifically targets the 3′UTR of FHL1. Furthermore, using DNA bisulfite modification and sequencing experiments, we demonstrated that the FHL1 promoter is hypermethylated in cancer cells. FHL1 methylation is increased upon miR-410 expression, suggesting that the regulation of FHL1 by miR-410 occurs by a dual mechanism. Using chromatin immunoprecipitation assays, we observed that miR-410 overexpression results in the increased binding of DNMT3A at the FHL1 promoter, which could explain how miR-410 regulates FHL1 methylation. Importantly, in vitro and in vivo results suggest that miR-410 may have oncogenic properties. Furthermore, both miR-410 and DNMT3A are upregulated in clinical human liver and colorectal tumors cancers. Our results suggest that miR-410 may function as an oncomiR and are consistent with its key function in regulating FHL1 in certain digestive system cancers.

Caveolin and cavin family members: dual roles in cancer

Caveolae are specialized plasma membrane subdomains with distinct lipid and protein compositions, which play an essential role in cell physiology through regulation of trafficking and signaling functions. The structure and functions of caveolae have been shown to require the proteins caveolins. Recently, members of the cavin protein family were found to be required, in concert with caveolins, for the formation and function of caveolae. Caveolins have a paradoxical role in the development of cancer formation. They have been involved in both tumor suppression and oncogenesis, depending on tumor type and progress stage. High expression of caveolins and cavins leads to inhibition of cancer-related pathways, such as growth factor signaling pathways. However, certain cancer cells that express caveolins and cavins have been shown to be more aggressive and metastatic because of their increased potential for anchorage-independent growth. Here, we will survey the functional roles of caveolins and of different cavin family members in cancer regulation.

Molecular differences between human thyroid follicular adenoma and carcinoma revealed by analysis of a murine model of thyroid cancer

Mouse models can provide useful information to understand molecular mechanisms of human tumorigenesis. In this study, the conditional thyroid mutagenesis of Pten and Ras genes in the mouse, which induces very aggressive follicular carcinomas (FTCs), has been used to identify genes differentially expressed among human normal thyroid tissue (NT), follicular adenoma (FA), and FTC. Global gene expression of mouse FTC was compared with that of mouse normal thyroids: 911 genes were found deregulated ± 2-fold in FTC samples. Then the expression of 45 deregulated genes in mouse tumors was investigated by quantitative RT-PCR in a first cohort of human NT, FA, and FTC (discovery group). Five genes were found significantly down-regulated in FA and FTC compared with NT. However, 17 genes were found differentially expressed between FA and FTC: 5 and 12 genes were overexpressed and underexpressed in FTC vs FA, respectively. Finally, 7 gene products, selected from results obtained in the discovery group, were investigated in a second cohort of human tumors (validation group) by immunohistochemistry. Four proteins showed significant differences between FA and FTC (peroxisomal proliferator-activated receptor-γ, serum deprivation response protein, osteoglycin, and dipeptidase 1). Altogether our data indicate that the establishment of an enriched panel of molecular biomarkers using data coming from mouse thyroid tumors and validated in human specimens may help to set up a more valid platform to further improve diagnosis and prognosis of thyroid malignancies.

PTRF/cavin-1 neutralizes non-caveolar caveolin-1 microdomains in prostate cancer

Caveolin-1 has a complex role in prostate cancer and has been suggested to be a potential biomarker and therapeutic target. As mature caveolin-1 resides in caveolae, invaginated lipid raft domains at the plasma membrane, caveolae have been suggested as a tumor-promoting signaling platform in prostate cancer. However, caveola formation requires both caveolin-1 and cavin-1 (also known as PTRF; polymerase I and transcript release factor). Here, we examined the expression of cavin-1 in prostate epithelia and stroma using tissue microarray including normal, non-malignant and malignant prostate tissues. We found that caveolin-1 was induced without the presence of cavin-1 in advanced prostate carcinoma, an expression pattern mirrored in the PC-3 cell line. In contrast, normal prostate epithelia expressed neither caveolin-1 nor cavin-1, while prostate stroma highly expressed both caveolin-1 and cavin-1. Utilizing PC-3 cells as a suitable model for caveolin-1-positive advanced prostate cancer, we found that cavin-1 expression in PC-3 cells inhibits anchorage-independent growth, and reduces in vivo tumor growth and metastasis in an orthotopic prostate cancer xenograft mouse model. The expression of α-smooth muscle actin in stroma along with interleukin-6 (IL-6) in cancer cells was also decreased in tumors of mice bearing PC-3-cavin-1 tumor cells. To determine whether cavin-1 acts by neutralizing caveolin-1, we expressed cavin-1 in caveolin-1-negative prostate cancer LNCaP and 22Rv1 cells. Caveolin-1 but not cavin-1 expression increased anchorage-independent growth in LNCaP and 22Rv1 cells. Cavin-1 co-expression reversed caveolin-1 effects in caveolin-1-positive LNCaP cells. Taken together, these results suggest that caveolin-1 in advanced prostate cancer is present outside of caveolae, because of the lack of cavin-1 expression. Cavin-1 expression attenuates the effects of non-caveolar caveolin-1 microdomains partly via reduced IL-6 microenvironmental function. With circulating caveolin-1 as a potential biomarker for advanced prostate cancer, identification of the molecular pathways affected by cavin-1 could provide novel therapeutic targets.

Differentially expressed androgen-regulated genes in androgen-sensitive tissues reveal potential biomarkers of early prostate cancer

Background

Several data favor androgen receptor implication in prostate cancer initiation through the induction of several gene activation programs. The aim of the study is to identify potential biomarkers for early diagnosis of prostate cancer (PCa) among androgen-regulated genes (ARG) and to evaluate comparative expression of these genes in normal prostate and normal prostate-related androgen-sensitive tissues that do not (or rarely) give rise to cancer.

Methods

ARG were selected in non-neoplastic adult human prostatic epithelial RWPE-1 cells stably expressing an exogenous human androgen receptor, using RNA-microarrays and validation by qRT-PCR. Expression of 48 preselected genes was quantified in tissue samples (seminal vesicles, prostate transitional zones and prostate cancers, benign prostatic hypertrophy obtained from surgical specimens) using TaqMan® low-density arrays. The diagnostic performances of these potential biomarkers were compared to that of genes known to be associated with PCa (i.e. PCA3 and DLX1).

Results and Discussion

By crossing expression studies in 26 matched PCa and normal prostate transitional zone samples, and 35 matched seminal vesicle and PCa samples, 14 genes were identified. Similarly, 9 genes were overexpressed in 15 benign prostatic hypertrophy samples, as compared to PCa samples. Overall, we selected 8 genes of interest to evaluate their diagnostic performances in comparison with that of PCA3 and DLX1. Among them, 3 genes: CRYAB, KCNMA1 and SDPR, were overexpressed in all 3 reference non-cancerous tissues. The areas under ROC curves of these genes reached those of PCA3 (0.91) and DLX1 (0.94).

Conclusions

We identified ARG with reduced expression in PCa and with significant diagnostic values for discriminating between cancerous and non-cancerous prostatic tissues, similar that of PCA3. Given their expression pattern, they could be considered as potentially protective against prostate cancer. Moreover, they could be complementary to known genes overexpressed in PCa and included along with them in multiplex diagnostic tools.

SRC points the way to biomarkers and chemotherapeutic targets

The role of Src in tumorigenesis has been extensively studied since the work of Peyton Rous over a hundred years ago. Src is a non-receptor tyrosine kinase that plays key roles in signaling pathways controlling tumor cell growth and migration. Src regulates the activities of numerous molecules to induce cell transformation. However, transformed cells do not always migrate and realize their tumorigenic potential. They can be normalized by surrounding nontransformed cells by a process called contact normalization. Tumor cells need to override contact normalization to become malignant or metastatic. In this review, we discuss the role of Src in cell migration and contact normalization, with emphasis on Cas and Abl pathways. This paradigm illuminates several chemotherapeutic targets and may lead to the identification of new biomarkers and the development of effective anticancer treatments.

High prevalence of epigenetic inactivation of the human four and a half LIM domains 1 gene in human oral cancer

The four and a half LIM domains 1 (FHL1) gene has been related to carcinogenesis. However, the expression status of FHL1 in human oral squamous cell carcinoma (OSCC) remains unclear and the detailed mechanism of gene silencing is poorly understood. The aim of this study was to examine the FHL1 expression level and its regulatory mechanism in OSCCs. Quantitative reverse-transcriptase-polymerase chain reaction (PCR) and western blotting showed significant downregulation of FHL1 in all OSCC-derived cell lines (Sa3, HSC-2, HSC-3, HSC-4, HO-1-u-1, HO-1-N-1, KON and Ca9-22) compared to human normal oral keratinocytes. We also found that FHL1 mRNA expression was frequently downregulated (P<0.01) in 51 (86.4%) of 59 primary OSCCs compared with the corresponding normal oral tissues, while there was no significant difference between the status of the FHL1 protein expression in OSCCs and the clinicopathological features. Using methylation-specific PCR, we detected methylated FHL1 in all cell lines and treatment with the DNA methyltransferase inhibitor, 5-aza-2'-deoxycytidine restored the FHL1 expression. However, no significant restoration of FHL1 expression was observed using sodium butyrate, an inhibitor of histone deacetylase and chromatin immunoprecipitation showed that histone H3 lysine 9 in the FHL1 promoter region was significantly acetylated. In addition, no mutation in the entire coding region of the FHL1 gene was found. Therefore, our data suggested that inactivation of the FHL1 gene is a frequent event during oral carcinogenesis and that the mechanism of FHL1 downregulation in OSCCs is through DNA methylation of the promoter region rather than histone deacetylation or mutation.

Plant lectin can target receptors containing sialic acid, exemplified by podoplanin, to inhibit transformed cell growth and migration

Cancer is a leading cause of death of men and women worldwide. Tumor cell motility contributes to metastatic invasion that causes the vast majority of cancer deaths. Extracellular receptors modified by α2,3-sialic acids that promote this motility can serve as ideal chemotherapeutic targets. For example, the extracellular domain of the mucin receptor podoplanin (PDPN) is highly O-glycosylated with α2,3-sialic acid linked to galactose. PDPN is activated by endogenous ligands to induce tumor cell motility and metastasis. Dietary lectins that target proteins containing α2,3-sialic acid inhibit tumor cell growth. However, anti-cancer lectins that have been examined thus far target receptors that have not been identified. We report here that a lectin from the seeds of Maackia amurensis (MASL) with affinity for O-linked carbohydrate chains containing sialic acid targets PDPN to inhibit transformed cell growth and motility at nanomolar concentrations. Interestingly, the biological activity of this lectin survives gastrointestinal proteolysis and enters the cardiovascular system to inhibit melanoma cell growth, migration, and tumorigenesis. These studies demonstrate how lectins may be used to help develop dietary agents that target specific receptors to combat malignant cell growth.

Downregulation and antiproliferative role of FHL3 in breast cancer

Four and a half LIM domain (FHL) protein 3 is a member of the FHL protein family that plays roles in the regulation of signal transduction, cell adhesion, survival, and mobility. FHL3 has been implicated in the development and progression of liver cancer. However, the biological function of FHL3 in other cancers remains unclear. Here, we show that FHL3 is downregulated in breast cancer patients. Using small interfering RNA (siRNA) knockdown and/or overexpression experiments, we demonstrated that FHL3 suppressed anchorage-dependent and -independent growth of human breast cancer cells. The antiproliferative effects of FHL3 on breast cancer cell growth were associated with both the G1 and the G2/M cell cycle arrest, which was accompanied by a marked inhibition of the G1-phase marker cyclin D1 and the G2/M-phase marker cyclin B1 as well as the induction of the cyclin dependent kinase inhibitor p21 (WAF1/CIP1), a negative regulator of cell cycle progression at G1 and G2. These results suggest that FHL3 may play a role in the development and progression of breast cancer, and thereby may be a potential target for human breast cancer gene therapy.

FHL1 on chromosome X is a single-hit gastrointestinal tumor-suppressor gene and contributes to the formation of an epigenetic field defect

Tumor-suppressor genes on chromosome X can be inactivated by a single hit, any of the point mutations, chromosomal loss and aberrant DNA methylation. As aberrant DNA methylation can be induced frequently, we here aimed to identify a tumor-suppressor gene on chromosome X inactivated by promoter DNA methylation. Of 69 genes on chromosome X upregulated by treatment of a gastric cancer cell line with a DNA-demethylating agent, 5-aza-2'-deoxycytidine, 11 genes had low or no expression in the cell line and abundant expression in normal gastric mucosae. Among them, FHL1 was frequently methylation-silenced in gastric and colon cancer cell lines, and methylated in primary gastric (21/80) and colon (5/50) cancers. Knockdown of the endogenous FHL1 in two cell lines by two kinds of shRNAs significantly increased cell growth in vitro and sizes of xenografts in nude mice. Expression of exogenous FHL1 in a non-expressing cell line significantly reduced its migration, invasion and growth. Notably, a somatic mutation (G642T; Lys214Asn) was identified in one of 144 colon cancer specimens, and the mutant FHL1 was shown to lack its inhibitory effects on migration, invasion and growth. FHL1 methylation was associated with Helicobacter pylori infection and accumulated in normal-appearing gastric mucosae of gastric cancer patients. These data showed that FHL1 is a methylation-silenced tumor-suppressor gene on chromosome X in gastrointestinal cancers, and that its silencing contributes to the formation of an epigenetic field for cancerization.