Testin is a tumor suppressor and prognostic marker in breast cancer

The value of lung function assessment and Testin expression detection in clinicopathological features and prognosis of NSCLC patients

OBJECTIVE

The aim of this study is to investigate the clinical value and potential prognostic significance of lung function assessment and Testin expression in non-small cell lung cancer (NSCLC) patients.

METHODS

The NSCLC patients were classified into three groups according to lung function: group of normal lung function, group of PRISm (preserved ratio impaired spirometry) (FEV1, forced expiratory volume during the first second < 80% predicted and FEV1/FVC (forced vital capacity) ≥ 70%) and group of COPD (chronic obstructive pulmonary disease) (FEV1/FVC < 70%). The pre-operational clinicopathological characteristics of these patients were recorded and the markers of systemic inflammatory response, including neutrophil to lymphocyte ratio (NLR), lymphocyte to monocyte ratio (LMR), platelet to lymphocyte ratio (PLR) and eosinophils (EOS), were compared between three groups. The expression of Testin in NSCLC samples was detected by IHC and we further explored the correlation between Testin expression and clinicopathological characteristics and prognosis of NSCLC patients. Finally, Cox regression analysis was conducted to study the prognostic factors of NSCLC patients.

RESULTS

Of the 158 NSCLC patients, percentages of normal lung function, PRISm and COPD were 41.4%, 22.8% and 36.1%, respectively. Patients with tumor in the left lung were more likely to have pulmonary dysfunction (PRISm and COPD) than the right lung. The markers of systemic inflammatory response showed differences to various degree in the three groups and NSCLC patients with PRISm or COPD presented more unfavorable prognosis than patients with normal function. The expression of Testin correlated with lymph node metastasis, TNM stage and tumor invasion of NSCLC patients. Moreover, patients with low Testin expression exhibited poorer disease-free survival and overall survival than those with high Testin expression. In Cox regression analysis, we found that PRISm, COPD and Testin expression served as prognostic factors in NSCLC patients.

CONCLUSIONS

The presence of COPD or PRISm influenced systemic inflammatory response and prognosis of NSCLC patients. Testin expression correlated with clinicopathological features and could be potentially used as a prognostic marker in NSCLC.

Discovery of Selective Histone Deacetylase 1 and 2 Inhibitors: Screening of a Focused Library Constructed by Click Chemistry, Kinetic Binding Analysis, and Biological Evaluation

Histone deacetylase 1 and 2 (HDAC1/2) inhibitors are potentially useful as tools for probing the biological functions of the isoforms and as therapeutic agents for cancer and neurodegenerative disorders. To discover potent and selective inhibitors, we screened a focused library synthesized by using click chemistry and obtained KPZ560 as an HDAC1/2-selective inhibitor. Kinetic binding analysis revealed that KPZ560 inhibits HDAC2 through a two-step slow-binding mechanism. In cellular assays, KPZ560 induced a dose- and time-dependent increase of histone acetylation and showed potent breast cancer cell growth-inhibitory activity. In addition, gene expression analyses suggested that the two-step slow-binding inhibition by KPZ560 regulated the expression of genes associated with cell proliferation and DNA damage. KPZ560 also induced neurite outgrowth of Neuro-2a cells and an increase in the spine density of granule neuron dendrites of mice. The unique two-step slow-binding character of o-aminoanilides such as KPZ560 makes them interesting candidates as therapeutic agents.

The Expression of Testin, Ki-67 and p16 in Cervical Cancer Diagnostics

Testin is a protein expressed in normal human tissues, being responsible, with other cytoskeleton proteins, for the proper functioning of cell−cell junction areas and focal adhesion plaques. It takes part in the regulation of actin filament changes during cell spreading and motility. Loss of heterozygosity in the testin-encoding gene results in altered protein expression in many malignancies, as partly described for cervical cancer. The aim of our study was the assessment of the immunohistochemical (IHC) expression of testin in cervical cancer and its analysis in regard to clinical data as well the expression of the Ki-67 antigen and p16 protein. Moreover, testin expression was assessed by Western blot (WB) in commercially available cell lines. The IHC analysis disclosed that the expression of testin inversely correlated with p16 (r = −0.2104, p < 0.0465) and Ki-67 expression (r = −0.2359, p < 0.0278). Moreover, weaker testin expression was observed in cancer cases vs. control ones (p < 0.0113). The WB analysis of testin expression in the cervical cancer cell lines corresponded to the IHC results and showed a weaker expression compared to that in the control cell line. When we compared the expression of testin in cervical cancer cell lines, we found a weaker expression in HPV-negative cell lines. In summary, we found that the intensity of testin expression and the number of positive cells inversely correlated with the expression of Ki-67 (a marker of proliferation) and p16 (a marker of cell cycle dysregulation). This study shows that the combined assessment of testin, Ki-67 and p16 expression may improve cervical cancer diagnostics.

The relationship between TESTIN expression and the prognosis of colorectal cancer

BACKGROUND

Colorectal carcinoma (CRC) represents a most grave healthy burden worldwide. TESTIN has been confirmed as a predictive biomarker for several cancers. In the present study, we sought to assess the expression level and prognostic values of TESTIN in CRC.

METHODS

The levels of TESTIN mRNA and protein were detected in 132 paired CRC tissues and noncancerous ones via quantitative real-time polymerase chain reaction (qRT-PCR) and immunohistochemistry (IHC) assays, respectively. Chi-square test was adopted to analyze the association of TESTIN expression with clinicopathological profiles of CRC patients. To explore prognostic value of TESTIN, Kaplan-Meier curve and Cox regression analyses were employed.

RESULTS

TESTIN expression was down-regulated among CRC tissues in comparison to bordering cancer-free samples at both protein and mRNA levels (P < 0.001). Decreased TESTIN expression was closely related to poor tumor differentiation (P = 0.001) and advanced TNM stages (P = 0.001). CRC cases with low expression of TESTIN were more likely to undergo dismal overall survivals (log-rank P = 0.003). Multivariate Cox analysis unveiled that down-regulated expression of TESTIN was independently correlated with poor prognosis (HR=2.422, 95% CI=1.294-4.535, P = 0.006).

CONCLUSION

The down-regulation of TESTIN may predict dismal prognosis for CRC patients.

Stress fiber strain recognition by the LIM protein testin is cryptic and mediated by RhoA

The actin cytoskeleton is a key regulator of mechanical processes in cells. The family of LIM domain proteins have recently emerged as important mechanoresponsive cytoskeletal elements capable of sensing strain in the actin cytoskeleton. The mechanisms regulating this mechanosensitive behavior, however, remain poorly understood. Here we show that the LIM domain protein testin is peculiar in that despite the full-length protein primarily appearing diffuse in the cytoplasm, the C-terminal LIM domains alone recognize focal adhesions and strained actin, while the N-terminal domains alone recognize stress fibers. Phosphorylation mutations in the dimerization regions of testin, however, reveal its mechanosensitivity and cause it to relocate to focal adhesions and sites of strain in the actin cytoskeleton. Finally, we demonstrate that activated RhoA causes testin to adorn stress fibers and become mechanosensitive. Together, our data show that testin’s mechanoresponse is regulated in cells and provide new insights into LIM domain protein recognition of the actin cytoskeleton’s mechanical state.

Silencing of Testin expression is a frequent event in spontaneous lymphomas from Trp53-mutant mice

The tumour suppressor gene, TES, is frequently methylated in many human tumours. Previously, we demonstrated that TES promoter methylation and transcriptional silencing was the most common molecular abnormality detected in childhood acute lymphoblastic leukaemia (ALL). Trp53-mutant mouse models predominantly develop B- and T-cell lymphomas, which are widely considered equivalent to childhood T and B ALL. In this study, we examined expression of Tes transcript and Testin protein in spontaneous tumours obtained from three Trp53-mutant mouse models. Using immunohistochemistry, we report that 47% of lymphomas lacked Testin protein compared to only 7% of non-lymphoid tumours. Further examination of the lymphomas from Trp53-null and Trp53-mΔpro homozygous mutant mice revealed that 63% and 69% respectively of the isolated lymphomas were Testin negative, which is similar to reported rates in childhood T-ALL. Surprisingly, lymphomas from Trp53-Δ122 mice were frequently Testin positive (> 60%), suggesting that the presence of the Trp53-Δ122 protein appeared to mitigate the requirement for Tes silencing in lymphomagenesis. Quantitative RT-PCR results confirmed that this lack of Testin protein was due to Tes transcriptional silencing, although bisulfite sequencing demonstrated that this was not due to promoter methylation. These results are consistent with the Testin protein having lymphoid tumour suppressor activity in both mice and humans.

Response gene to complement-32 promotes cell survival via the NF-κB pathway in non-small-cell lung cancer

Response gene to complement (RGC)-32 regulates the cell cycle in response to complement activation. The present study demonstrated that the expression level of RGC-32 is higher in human non-small-cell lung cancer (NSCLC) tissues compared with health controls. Overexpressing RGC-32 induced p65 nucleus translocation, significantly increased nuclear p65 levels and promoted the proliferation of A549 cells. Knockdown of RGC-32 by short hairpin RNA decreased the expression level of nuclear p65 and inhibited cell proliferation. The increase in cell proliferation induced by RGC32 could be abolished by the NF-κB inhibitor pyrrolidine dithiocarbamate. Mechanistic studies indicated that RGC32 mediated NF-κB downstream genes, including vascular cell adhesion protein 1, interleukin-6, cyclin dependent kinase inhibitor 2C, testin and vascular endothelial growth factor A. In summary, the present study demonstrated a novel role of RGC-32 in the progression of NSCLC via the NF-κB pathway and p65. Therefore, RGC-32 could be a potential therapeutic target for NSCLC.

The Role of Testin in Human Cancers

Testin is a protein expressed in almost all normal human tissues. It locates in the cytoplasm along stress fibers being recruited to focal adhesions. Together with zyxin and vasodilator stimulated protein it forms complexes with various cytoskeleton proteins such as actin, talin and paxilin. They jointly play significant role in cell motility and adhesion. In addition, their involvement in the cell cycle has been demonstrated. Expression of testin protein level correlates positively with percentage of cells in G1 phase, while overexpression can induce apoptosis and decreased colony forming ability. Decreased testin expression associate with loss by cells epithelial morphology and gain migratory and invasive properties of mesenchymal cells. Latest reports indicate that TES is a tumor suppressor gene which can contribute to cancerogenesis but the mechanism of loss TES gene expression is still unknown. Some authors point out hypermethylation of the CpG island as a main factor, however loss of heterozygosity may also play an important role [4, 5]. The altered expression of testin was found in malignant neoplasm, i.a. ovarian, lung, head and neck squamous cell cancer, breast, endometrial, colorectal, prostate and gastric cancers [1-9]. Testin participate in the processes of tumor growth, angiogenesis, and metastasis [10]. Many researchers stated involvement of testin in tumor progression, what suggest its potential usage in immunotherapy [7, 11]. Understanding the molecular functions of testin may be crucial in development personalized treatment. In the present manuscript up-to-date review of literature can be found.

CFP suppresses breast cancer cell growth by TES-mediated upregulation of the transcription factor DDIT3

Breast cancer is a heterogeneous genetic disease driven by the accumulation of individual mutations per tumor. Whole-genome sequencing approaches have identified numerous genes with recurrent mutations in primary tumors. Although mutations in well characterized tumor suppressors and oncogenes are overrepresented in these sets, the majority of the genetically altered genes have so far unknown roles in breast cancer progression. To improve the basic understanding of the complex disease breast cancer and to potentially identify novel drug targets or regulators of known cancer-driving pathways, we analyzed 86 wild-type genes and 94 mutated variants for their effect on cell growth using a serially constructed panel of MCF7 cell lines. We demonstrate in subsequent experiments that the metal cation transporter CNNM4 regulates growth by induction of apoptosis and identified a tumor suppressive role of complement factor properdin (CFP) in vitro and in vivo. CFP appears to induce the intracellular upregulation of the pro-apoptotic transcription factor DDIT3 which is associated with endoplasmic reticulum-stress response.

TES functions as a Mena-dependent tumor suppressor in gastric cancer carcinogenesis and metastasis

Background

In our previous study, we identified a candidate tumor suppressor gene, testin LIM domain protein (TES), in primary gastric cancer (GC). TES contains three LIM domains, which are specific interacting regions for the cell adhesion and cytoskeleton regulatory proteins. Mena is a known cytoskeleton regulator that regulates the assembly of actin filaments and modulates cell adhesion and motility by interacting with Lamellipodin (Lpd). Therefore, we hypothesized that TES plays a role as tumor suppressor in GC through interacting with Mena. This study aimed to investigate the tumor suppressive functions of TES in GC.

Methods

We explored the tumor suppressive effect of TES in GC by in vitro cell proliferation assay, colony formation assay, cell cycle analysis, Transwell assays, and in vivo tumorigenicity and metastasis assays. The interaction of TES and Mena was investigated through immunoprecipitation-based mass spectrometry. We also analyzed the expression of TES and Mena in 172 GC specimens using immunohistochemistry and investigated the clinicopathological and prognostic significance of TES and Mena in GC.

Results

TES suppressed GC cell proliferation and colony formation, induced cell cycle arrest, and inhibited tumorigenicity in vitro. Additionally, it inhibited GC cell migration and invasion in vitro and suppressed metastasis in vivo. TES interacted with Mena, and inhibited the interaction of Mena with Lpd. Transwell assays suggested that TES suppressed migration and invasion of GC cells in a Mena-dependent fashion. In GC patients with high Mena expression, the expression of TES was associated with tumor infiltration (P = 0.005), lymph node metastasis (P = 0.003), TNM stage (P = 0.003), and prognosis (P = 0.010). However, no significant association was observed in GC patients with low Mena expression.

Conclusions

We believe that TES functions as a Mena-dependent tumor suppressor. TES represents a valuable prognostic marker and potential target for GC treatment.

Electronic supplementary material

The online version of this article (10.1186/s40880-019-0347-y) contains supplementary material, which is available to authorized users.

The Different Facades of Retinal and Choroidal Endothelial Cells in Response to Hypoxia

Ocular angiogenic diseases, such as proliferative diabetic retinopathy and neovascular age-related macular degeneration, are associated with severe loss of vision. These pathologies originate from different vascular beds, retinal and choroidal microvasculatures, respectively. The activation of endothelial cells (EC) plays pivotal roles in angiogenesis, often triggered by oxygen deficiency. Hypoxia-inducible factors in ECs mediate the transcription of multiple angiogenic genes, including the canonical vascular endothelial growth factors. ECs show notable heterogeneity in function, structure, and disease, therefore the understanding of retinal/choroidal ECs (REC; CEC) biochemical and molecular responses to hypoxia may offer key insights into tissue-specific vascular targeting treatments. The aim of this review is to discuss the differences spanning between REC and CEC, with focus on their response to hypoxia, which could provide innovative and sustainable strategies for site specific targeting of ocular neovascularization.

Testin protects against cardiac hypertrophy by targeting a calcineurin-dependent signalling pathway

Multiple organs express testin (TES), including the heart. Nevertheless, current understanding of the influence of TES on cardiovascular diseases, especially on cardiac hypertrophy and its etiology, is insufficient. This study investigated the influence of TES on cardiac hypertrophy and its etiology. Murine models with excessive TES expression specific to the heart were constructed with an adeno-associated virus expression system. Cardiac hypertrophy was stimulated through aortic banding (AB). The severity of cardiac hypertrophy was evaluated through molecular, echocardiographic, pathological, and hemodynamic examination. The findings of our study revealed that TES expression was remarkably suppressed not only in failing human hearts but also in mouse hearts with cardiac hypertrophy. It was discovered that excessive TES expression driven by an adeno-associated viral vector noticeably inhibited hypertrophy triggered by angiotensin II (Ang II) in cultivated cardiomyocytes from newborn rats. It was also revealed that TES knockdown via AdshTES caused the reverse phenotype in cardiomyocytes. Furthermore, it was proved that excessive TES expression attenuated the ventricular dilation, cardiac hypertrophy, dysfunction, and fibrosis triggered by AB in mice. It was discovered that TES directly interacted with calcineurin and suppressed its downstream signalling pathway. Moreover, the inactivation of calcineurin with cyclosporin A greatly offset the exacerbated hypertrophic response triggered by AB in TES knockdown mice. Overall, the findings of our study suggest that TES serves as a crucial regulator of the hypertrophic reaction by hindering the calcineurin-dependent pathway in the heart.

Angiogenic and Immunologic Proteins Identified by Deep Proteomic Profiling of Human Retinal and Choroidal Vascular Endothelial Cells: Potential Targets for New Biologic Drugs

PURPOSE

Diseases that involve retinal or choroidal vascular endothelial cells are leading causes of vision loss: age-related macular degeneration, retinal ischemic vasculopathies, and noninfectious posterior uveitis. Proteins differentially expressed by these endothelial cell populations are potential drug targets. We used deep proteomic profiling to define the molecular phenotype of human retinal and choroidal endothelial cells at the protein level.

METHODS

Retinal and choroidal vascular endothelial cells were separately isolated from 5 human eye pairs by selection on CD31. Total protein was extracted and digested, and peptide fractions were analyzed by reverse-phase liquid chromatography tandem mass spectrometry. Peptide sequences were assigned to fragment ion spectra, and proteins were inferred from openly accessible protein databases. Protein abundance was determined by spectral counting. Publicly available software packages were used to identify proteins that were differentially expressed between human retinal and choroidal endothelial cells, and to classify proteins that were highly abundant in each endothelial cell population.

RESULTS

Human retinal and/or choroidal vascular endothelial cells expressed 5042 nonredundant proteins. Setting the differential expression false discovery rate at 0.05, 498 proteins of 3454 quantifiable proteins (14.4%) with minimum mean spectral counts of 2.5 were differentially abundant in the 2 cell populations. Retinal and choroidal endothelial cells were enriched in angiogenic proteins, and retinal endothelial cells were also enriched in immunologic proteins.

CONCLUSIONS

This work describes the different protein expression profiles of human retinal and choroidal vascular endothelial cells, and provides multiple candidates for further study as novel treatments or drug targets for posterior eye diseases. NOTE: Publication of this article is sponsored by the American Ophthalmological Society.

Expression of Tim-3 in breast cancer tissue promotes tumor progression

T-cell immunoglobulin mucin-3 (Tim-3) plays a pivotal role in immune regulation and tolerance induction as a negative regulatory molecule on innate versus adaptive immune cells, especially in antitumor immunity. However, the mechanism of Tim-3 expression on tumor cells and the mechanism that inhibits anti-tumor immunity are obscure. In this present study, we aimed to investigate the functions of Tim-3 in breast cancer and to explore its correlation to tumor prognosis. In a total of 42 clinical samples of invasive breast cancer, Tim-3 was semiquantitatively scored based on both distribution and intensity of immunohistochemistry staining and was found to correlate with clinicopathological parameters. Western blotting was used to detect the expression of Tim-3 in breast cancer cells. Furthermore, the effect of Tim-3 in breast cancer cells was evaluated after overexpression by ADV-Tim-3 and downregulation by Tim-3-siRNA. High immunoreactivity of Tim-3 was found to be significantly correlated with clinical stage, metastasis, KI67, and a lower 5-year survival rate. We supported this finding by confirming the presence of Tim-3 protein in the breast cell lines. Downregulation of Tim-3 significantly inhibited the proliferation, migration, and invasion of breast cancer cells while it promoted apoptosis. Overexpression of Tim-3 promoted the proliferation, migration, and invasion of breast cancer cells and inhibited apoptosis. Taken together, as a valuable marker of breast cancer prognosis, Tim-3 in breast cancer cells play an important role in the progression of breast cancer and may be an effective novel target in tumor prevention and treatment.

The PET and LIM1-2 domains of testin contribute to intramolecular and homodimeric interactions

The focal adhesion protein testin is a modular scaffold and tumour suppressor that consists of an N-terminal cysteine rich (CR) domain, a PET domain of unknown function and three C-terminal LIM domains. Testin has been proposed to have an open and a closed conformation based on the observation that its N-terminal half and C-terminal half directly interact. Here we extend the testin conformational model by demonstrating that testin can also form an antiparallel homodimer. In support of this extended model we determined that the testin region (amino acids 52–233) harbouring the PET domain interacts with the C-terminal LIM1-2 domains in vitro and in cells, and assign a critical role to tyrosine 288 in this interaction.

Germline large genomic alterations on 7q in patients with multiple primary cancers

Patients with multiple primary cancers (MPCs) are suspected to have a hereditary cancer syndrome. However, only a small proportion may be explained by mutations in high-penetrance genes. We investigate two unrelated MPC patients that met Hereditary Breast and Ovaria Cancer criteria, both presenting triple negative breast tumors and no mutations in BRCA1, BRCA2 and TP53 genes. Germline rearrangements on chromosome 7q, involving over 40 Mb of the same region, were found in both patients: one with mosaic loss (80% of cells) and the other with cnLOH (copy-neutral loss of heterozygosity) secondary to maternal allele duplication. Five children tested had no alterations on 7q. The patients shared 330 genes in common on 7q22.1-q34, including several tumor suppressor genes (TSGs) previously related to breast cancer risk and imprinted genes. The analysis of the triple negative BC from one patient revealed a mosaic gain of 7q translated for over-expressed cancer-related genes. The involvement of TSGs and imprinted genes, mapped on 7q, has the potential of being associated to MPC risk, as well as cancer progression. To our knowledge, this is the first description of patients with MPCs that harbor constitutive large alterations on 7q.

Trametes robiniophila may induce apoptosis and inhibit MMPs expression in the human gastric carcinoma cell line MKN-45

Gastric carcinoma (GC) is one of the most common malignant tumors and is mainly treated by invasive surgeries. The present study aimed to investigate the treatment potential of Trametes robiniophila on GC using the human GC cell line MKN-45. Cells were incubated with Trametes robiniophila at a concentration of 0, 5 and 10 mg/ml for 24 h. The apoptosis of the cell line was examined with acridine orange/ethidium bromide staining and flow cytometry. The expression of B-cell lymphoma (Bcl)-2, Fas, caspase-3, matrix metalloproteinase (MMP)-2 and MMP-9 was analyzed using reverse transcription-polymerase chain reaction and western blotting. With increasing drug concentrations, the proportion of apoptotic and necrotic cells increased. For a certain concentration, the apoptotic ratio also increased with increasing response times. Compared with the control group, the Bcl-2, MMP-2 and MMP-9 expression levels in the MKN-45 cell line decreased, while the expression levels of Fas and caspase-3 increased (P<0.05), and the expression patterns were strengthened with increasing drug concentrations. The present study revealed that Trametes robiniophila had treatment potential on GC, and it may act on gastric cells through apoptotic induction and MMPs expression inhibition. Based on the present results, Trametes robiniophila may be considered as an alternative approach for noninvasive therapy of GC. However, future studies should be performed to clarify this further.

Testin is a tumor suppressor in non-small cell lung cancer

The Testin gene was previously identified in the fragile chromosomal region FRA7G at 7q31.2. It has been implicated in several types of cancers including prostate, ovarian, breast and gastric cancer. In the present study, we investigated the function of the candidate tumor-suppressor Testin gene in non-small cell lung cancer (NSCLC). In NSCLC cell lines, we observed lower expression of Testin compared to that noted in normal human bronchial epithelial cells. MTT assays, flow cytometry, clonogenic assay and invasion assay showed that the overexpression of the Testin gene inhibited cancer cell proliferation, invasion and colony formation. In tumor xenograft models, Testin markedly inhibited lung cancer cell xenograft formation and growth in athymic nude mice. Taken together, these data suggest that Testin plays an important role in the development and progression of NSCLC. Testin may be an effective novel target in NSCLC prevention and treatment.

TESTIN Induces Rapid Death and Suppresses Proliferation in Childhood B Acute Lymphoblastic Leukaemia Cells

Background

Childhood acute lymphoblastic leukaemia (ALL) is the most common malignancy in children. Despite high cure rates, side effects and late consequences of the intensive treatments are common. Unquestionably, the identification of new therapeutic targets will lead to safer, more effective treatments. We identified TES promoter methylation and transcriptional silencing as a very common molecular abnormality in childhood ALL, irrespective of molecular subtype. The aims of the present study were to demonstrate that TES promoter methylation is aberrant, to determine the effects of TES re-expression in ALL, and to determine if those effects are mediated via TP53 activity.

Methods

Normal fetal and adult tissue DNA was isolated and TES promoter methylation determined by Sequenom MassARRAY. Quantitative RT-PCR and immunoblot were used to confirm re-expression of TES in ALL cell lines after 5’-aza-2’-deoxycytidine (decitabine) exposure or transfection with TES expression plasmids. The effects of TES re-expression on ALL cells were investigated using standard cell proliferation, cell death and cell cycle assays.

Results

In this study, we confirm that the TES promoter is unmethylated in normal adult and fetal tissues. We report that decitabine treatment of ALL cell lines results in demethylation of the TES promoter and attendant expression of TES mRNA. Re-expression of TESTIN protein in ALL cells using expression plasmid transfection results in rapid cell death or cell cycle arrest independent of TP53 activity.

Conclusions

These results suggest that TES is aberrantly methylated in ALL and that re-expression of TESTIN has anti-leukaemia effects which point to novel therapeutic opportunities for childhood ALL.

microRNA-29b: an emerging player in human cancer

MicroRNAs (miRNAs) are ubiquitously expressed small, non-coding RNAs that negatively regulate gene expression at a post transcriptional/translational level. They have emerging as playing crucial roles in cancer at all stages ranging from initiation to metastasis. As a tumor suppressor miRNA, aberrant expression of microRNA-29b (miR-29b) has been detected in various types of cancer, and its disturbance is related with tumor development and progression. In this review, we summarize the latest findings with regard to the tumor suppressor signature of miR-29b and its regulatory mechanisms. Our review highlights the diverse relationships between miR-29b and its target genes in malignant tumors.

Testin on Atherosclerosis in Rabbits

Background:

The expression of TES, a novel tumor suppressor gene, is found to be down-regulated in the left anterior descending aorta of patients with coronary artery disease (CAD) compared with non-CAD subjects. This study aimed to investigate the expression of TES during the development of atherosclerosis in rabbits.

Methods:

Thirty-two New Zealand rabbits were randomly divided into a normal diet (ND) and high-fat diet (HFD) groups. Body weight and serum lipid levels were measured at 0, 4, and 12 weeks after diet treatment. The degree of atherosclerosis in thoracic aortas was analyzed by histological examinations. The expression of Testin in the tissue samples was inspected via immunohistochemical and immunofluorescence confocal microscopy. Real time-polymerase chain reaction and Western blot analysis were performed to evaluate the expression of TES/Testin at mRNA and protein levels in the aortic tissues.

Results:

After 12 weeks postenrollment, rabbits in HFD group had a higher level of serum lipids and atherosclerotic plaque compared to ND group (P < 0.05). Testin expression was detected at high levels in the endothelium and a weak expression on the subendothelium area. The expression of TES mRNA was markedly reduced by 10-fold in the aortic tissues in the HFD group compared with the ND group (P = 0.015), and the protein level was also significantly decreased in the HFD group (P < 0.05).

Conclusions:

Reduced TES/Testin expression is associated with the development of atherosclerosis, implicating a potentially important role in the pathogenesis of atherosclerosis.

Racial variation in breast tumor promoter methylation in the Carolina Breast Cancer Study

BACKGROUND

African American (AA) women are diagnosed with more advanced breast cancers and have worse survival than white women, but a comprehensive understanding of the basis for this disparity remains unclear. Analysis of DNA methylation, an epigenetic mechanism that can regulate gene expression, could help to explain racial differences in breast tumor clinical biology and outcomes.

METHODS

DNA methylation was evaluated at 1,287 CpGs in the promoters of cancer-related genes in 517 breast tumors of AA (n = 216) or non-AA (n = 301) cases in the Carolina Breast Cancer Study (CBCS).

RESULTS

Multivariable linear regression analysis of all tumors, controlling for age, menopausal status, stage, intrinsic subtype, and multiple comparisons [false discovery rate (FDR)], identified seven CpG probes that showed significant (adjusted P < 0.05) differential methylation between AAs and non-AAs. Stratified analyses detected an additional four CpG probes differing by race within hormone receptor-negative (HR(-)) tumors. Genes differentially methylated by race included DSC2, KCNK4, GSTM1, AXL, DNAJC15, HBII-52, TUSC3, and TES; the methylation state of several of these genes may be associated with worse survival in AAs. TCGA breast tumor data confirmed the differential methylation by race and negative correlations with expression for most of these genes. Several loci also showed racial differences in methylation in peripheral blood leukocytes (PBL) from CBCS cases, indicating that these variations were not necessarily tumor-specific.

CONCLUSIONS

Racial differences in the methylation of cancer-related genes are detectable in both tumors and PBLs from breast cancer cases.

IMPACT

Epigenetic variation could contribute to differences in breast tumor development and outcomes between AAs and non-AAs.

Identification of microRNAs in Nipple Discharge as Potential Diagnostic Biomarkers for Breast Cancer

BACKGROUND

Intraductal breast cancer is generally difficult to diagnose because of a lack of an efficient method for detection. The purpose of this study was to reveal and validate the differential expression of microRNAs (miRNAs) in nipple discharge from intraductal papilloma patients and identify miRNAs as novel potential biomarkers for primary breast cancer.

METHODS

Nipple discharge samples were collected from three intraductal carcinoma breast cancer patients and three intraductal papilloma patients. The initial screening of miRNA expression was performed with an Axon GenePix 4000B microarray scanner using a novel approach to label miRNAs. The expression levels of the miRNAs selected from the initial screening were further examined by quantitative real-time polymerase chain reaction (qRT-PCR) in 21 validation samples (8 carcinomas and 13 benign tumors). An independent t test was used to detect significant correlations between the miRNA expression levels and breast cancer.

RESULTS

Microarray profiling demonstrated that three miRNAs were markedly up-regulated and three miRNAs were down-regulated in the intraductal carcinoma breast cancer patients compared to the papilloma group. The qRT-PCR analysis further verified that four miRNAs (miR-4484, miR-K12-5-5p, miR-3646, and miR-4732-5p) might serve as potential tumor biomarkers for breast cancer detection.

CONCLUSION

The novel approach of using a microarray scanner is applicable for studying biomarkers in nipple discharge containing small amounts of miRNA. miRNAs could serve as potential tumor biomarkers that can assist in breast cancer screening. Up-regulation of miR-4484, miR-K12-5-5p, and miR-3646 in nipple discharge may be a predictor of malignant breast cancer.

Knockdown of metadherin inhibits angiogenesis in breast cancer

Angiogenesis plays an important role in cancer growth, invasion and metastasis. It has been confirmed that metadherin (MTDH) is associated with angiogenesis. However, the detailed mechanism of MTDH on angiogenesis has not yet been reported. In this study, we demonstrate the anti-angiogenic function of MTDH in breast cancer. With RNA interference strategies, we found that knockdown of MTDH inhibits cellular angiogenesis both in vitro and ex vivo. Furthermore, we revealed that ERK1/2 pathway is involved in the anti-angiogenic function of MTDH, and the function can be partially reversed via upregulation of microRNA-21 (miR-21). In conclusion, knockdown of MTDH can inhibit angiogenesis in breast cancer. These results show that MTDH is a viable therapeutic target for anti-angiogenesis in breast cancer.

Molecular characterization of common fragile sites as a strategy to discover cancer susceptibility genes

The cytogenetic hypothesis that common fragile sites (cFSs) are hotspots of cancer breakpoints is increasingly supported by recent data from whole-genome profiles of different cancers. cFSs are components of the normal chromosome structure that are particularly prone to breakage under conditions of replication stress. In recent years, cFSs have become of increasing interest in cancer research, as they not only appear to be frequent targets of genomic alterations in progressive tumors, but also already in precancerous lesions. Despite growing evidence of their importance in disease development, most cFSs have not been investigated at the molecular level and most cFS genes have not been identified. In this review, we summarize the current data on molecularly characterized cFSs, their genetic and epigenetic characteristics, and put emphasis on less-studied cFS genes as potential contributors to cancer development.

TESTIN suppresses tumor growth and invasion via manipulating cell cycle progression in endometrial carcinoma

BACKGROUND

The TESTIN gene was demonstrated to be a tumor suppressor in prostate and breast cancer through inhibiting tumor growth and invasion. Herein, we aimed to investigate the detailed functions of TESTIN in the highly sexual hormone (estrogen)-dependent malignancy, endometrial carcinoma.

MATERIAL AND METHODS

TESTIN mRNA and protein expression were measured by qRT-PCR, Western blot and immunohistochemistry. Upregulation of TESTIN was achieved by transfecting the pcDNA3.1-TESTIN plasmids into AN3CA cells. Knockdown of TESTIN was achieved by transfecting the shRNA-TESTIN into Ishikawa cells. MTT assay, colony formation assay, and Transwell assay were used to investigate the effects of TESTIN on cellular proliferation and invasion. The apoptotic status and cell cycle were analyzed using flow cytometry. MMP2 secretion was determined by ELISA assay. The xenograft assay was used to investigate the functions of TESTIN in nude mice.

RESULTS

Compared to the non-malignant adjacent endometrium, 54% of tumor samples presented downregulation of TESTIN (P<0.001). Loss of TESTIN protein was correlated with advanced tumor stage (P=0.047), high grade (P=0.034), and lymphatic vascular space invasion (P=0.036). In vitro, overexpression of TESTIN suppressed cell proliferation, induced dramatic G1 arrest, and inhibited tumor invasion through blocking the secretion of MMP2. Loss of TESTIN accelerated cellular proliferation, promoted cell cycle progression, and enhanced tumor invasion by increasing the secretion of MMP2. Consistently, TESTIN could significantly delay the growth of xenografts in nude mice.

CONCLUSIONS

TESTIN was commonly downregulated in human endometrial carcinoma and was associated with poor prognostic markers. Moreover, TESTIN significantly inhibited tumor growth and invasion via arresting cell cycle in in vitro and in vivo experiments. Therefore, we propose that TESTIN might be a prognostic marker and therapeutic target for endometrial carcinoma.

Testin interacts with vangl2 genetically to regulate inner ear sensory cell orientation and the normal development of the female reproductive tract in mice

BACKGROUND

Planar cell polarity (PCP) signaling regulates the coordinated polarization of cells and is required for the normal development and function of many tissues. Previous studies have identified conserved PCP genes, such as Van Gogh-like 2 (Vangl2) and Prickle (Pk), in the regulation of coordinated orientation of inner ear hair cells and female reproductive tract development. Testin shares a PET-LIM homology with Pk. It is not clear whether Testin acts in PCP processes in mammals.

RESULTS

We identified Testin as a Vangl2-interacting protein through a 2-hybrid screen with a cochlea cDNA library. Testin is enriched to cell-cell boundaries in the presence of Vangl2 in cultured cells. Genetic inactivation of Testin leads to abnormal hair cell orientation in the vestibule and cellular patterning defects in the cochlea. In addition, Testin genetically interacts with Vangl2 to regulate hair cell orientation in the cochlea and the opening of the vaginal tract.

CONCLUSIONS

Our findings suggested Testin as a gene involved in coordinated hair cell orientation in the inner ear and in female reproductive tract development. Furthermore, its genetic interaction with Vangl2 implicated it as a potential molecular link, responsible for mediating the role of Vangl2-containing membranous PCP complexes in directing morphologic polarization.

53BP1 is a novel regulator of angiogenesis in breast cancer

In our previous study, we found that 53BP1 was a tumor suppressor and was associated with prognosis in breast cancer. However, little is known about its role in angiogenesis. In the present study, we aimed to reveal the role of 53BP1 in angiogenesis of breast cancer. With RNA interference and ectopic expression strategies to elucidate the detailed function of 53BP1 in angiogenesis, we observed that ectopic expression of 53BP1 inhibited cellular angiogenesis and 53BP1 RNA interference led to an increase in angiogenesis both in vitro and in vivo. In clinical breast cancer samples, 53BP1 was inversely correlated with CD31, MMP-2 and MMP-9 by immunohistochemistry analysis. Furthermore, we showed that the Akt pathway was involved in the antiangiogenesis function of 53BP1. Overall, our findings demonstrate that 53BP1 plays a vital role in inhibiting angiogenesis. These findings suggest that 53BP1 might provide a viable target therapy for breast cancer.

BRCC2 inhibits breast cancer cell growth and metastasis in vitro and in vivo via downregulating AKT pathway

In our previous study, we demonstrated that the BRCC2 (breast cancer cell 2) gene is a proapoptotic molecule that interacts with Bcl-X_L. BRCC2 downregulation is associated with poor disease-free and overall survival in breast cancer. In this study, we aimed to investigate the role of BRCC2 in tumor suppression in breast cancer. In clinical breast cancer samples, we found that BRCC2 expression was significantly downregulated in cancer lesions compared with paired normal breast tissues. By silencing or overexpressing BRCC2 in breast cancer cells, we found that BRCC2 could inhibit cell growth and metastasis in vitro. An in vivo assay showed that BRCC2 not only dramatically inhibited breast cancer cell xenograft formation and growth but also inhibited breast cancer cell metastasis in a lung metastasis model. Moreover, we demonstrated that BRCC2 inhibited breast cancer metastasis via regulation of the Akt pathway. Thus, our study provided evidence that BRCC2 functions as a novel tumor suppressor in breast cancer and may be a potential therapeutic target for breast cancer management.

Huaier aqueous extract suppresses human breast cancer cell proliferation through inhibition of estrogen receptor α signaling

Estrogen receptor α (ERα) has been reported to play a critical role in promoting the growth of breast tumor cells. In the present study, we explored the effect of Huaier extract on estrogen receptor α signaling in breast cancer cell lines. Our data demonstrated that Huaier extract effectively inhibited the proliferation of the MCF-7, T47D and ZR-75-1 human breast cancer cell lines. For the mechanism analysis, we demonstrated that Huaier extract significantly reduced the mRNA and protein levels of ERα in all three ERα-positive cell lines. The downregulation of ERα protein levels was correlated with activation of the proteasomes. We demonstrated that Huaier extract markedly decreased the expression of both ERα and its downstream genes, inhibited the estrogen-stimulated proliferation and reversed the estrogen-induced activation of the nuclear factor κB (NFκB) pathway. Our study provides evidence that Huaier extract is a novel estrogen receptor modulator and is a promising drug for the prevention and treatment of ERα-positive human breast cancers.

Testin is a tumor suppressor and prognostic marker in breast cancer

The testin (TES) gene was previously identified in the fragile chromosomal region FRA7G at 7q31.2. In the present study, we aimed to investigate the candidate tumor suppressor function of TES and explore its correlations to clinicopathologic features and prognosis in breast cancer. In clinical samples, we showed that the expression of TES decreased gradually from normal through ductal hyperplasia without atypia, atypical ductal hyperplasia, and ductal carcinoma in situ, to invasive ductal carcinoma. To explore the possible tumor suppressing function of TES, the expression of TES in breast cancer cells was manipulated by ectopic expression or by RNAi. We revealed that ectopic TES expression significantly inhibited cell proliferation, invasive ability, and angiogenesis, whereas knockdown of TES by RNAi enhanced cell proliferation, invasive ability, and angiogenesis. In an animal model, TES markedly inhibited breast cancer cell xenograft formation in athymic nude mice and reduced breast cancer cell metastasis to lung. Moreover, we revealed that TES inhibited the invasion and angiogenesis of breast cancer partially through miR-29b-mediated MMP-2 inhibition. Using the tissue microarray of breast cancer from Yale University, we found that lower TES expression was an independent prognostic factor for shorter overall survival and disease-free survival with univariate and multivariate analyses. Taken together, these data suggest that TES, as a valuable marker of breast cancer prognosis, plays an important role in the development and progression of breast cancer. TES may be an effective novel target in breast cancer prevention and treatment.