HOXA1-stimulated oncogenicity is mediated by selective upregulation of components of the p44/42 MAP kinase pathway in human mammary carcinoma cells

HOXA1 participates in VSMC-to-macrophage-like cell transformation via regulation of NF-κB p65 and KLF4: a potential mechanism of atherosclerosis pathogenesis

BACKGROUND

Macrophage-like transformation of vascular smooth muscle cells (VSMCs) is a risk factor of atherosclerosis (AS) progression. Transcription factor homeobox A1 (HOXA1) plays functional roles in differentiation and development. This study aims to explore the role of HOXA1 in VSMC transformation, thereby providing evidence for the potential mechanism of AS pathogenesis.

METHODS

High fat diet (HFD)-fed apolipoprotein E knockout (ApoE^-/-) mice were applied as an in vivo model to imitate AS, while 1-palmitoyl-2-(5-oxovaleroyl)-sn-glycero-3-phosphocholine (POV-PC)-treated VSMCs were applied as an in vitro model. Recombinant adeno-associated-virus-1 (AAV-1) vectors that express short-hairpin RNAs targeting HOXA1, herein referred as AAV1-shHOXA1, were generated for the loss-of-function experiments throughout the study.

RESULTS

In the aortic root of AS mice, lipid deposition was severer and HOXA1 expression was higher than the wide-type mice fed with normal diet or HFD. Silencing of HOXA1 inhibited the AS-induced weight gain, inflammatory response, serum and liver lipid metabolism disorder and atherosclerotic plaque formation. Besides, lesions from AS mice with HOXA1 knockdown showed less trans-differentiation of VSMCs to macrophage-like cells, along with a suppression of krüppel-like factor 4 (KLF4) and nuclear factor (NF)-κB RelA (p65) expression. In vitro experiments consistently confirmed that HOXA1 knockdown suppressed lipid accumulation, VSMC-to-macrophage phenotypic switch and inflammation in POV-PC-treated VSMCs. Mechanism investigations further illustrated that HOXA1 transcriptionally activated RelA and KLF4 to participate in the pathological manifestations of VSMCs.

CONCLUSIONS

HOXA1 participates in AS progression by regulating VSMCs plasticity via regulation of NF-κB p65 and KLF4. HOXA1 has the potential to be a biomarker or therapeutic target for AS.

HOXA1 is a radioresistance marker in multiple cancer types

Radiotherapy is an important therapeutic method for patients with cancer. However, radioresistance can cause treatment failure. Thus, there is an urgent need to investigate mechanisms of radioresistance and identity markers that could be used to predict radioresistance and prognosis of post-radiotherapy cancer patients. In the present study, we propose HOXA1 as a candidate biomarker of intrinsic radioresistance in multiple cancer types. By analyzing data from The Cancer Genome Atlas (TCGA), we found that HOXA1 was aberrantly upregulated in multiple cancers, and that elevated HOXA1 was significantly associated with poor prognosis of post-radiotherapy head and neck squamous cell carcinoma (HNSCC) and low-grade glioma (LGG) patients. Correlation analysis showed that HOXA1 expression was positively correlated with expression of EGFR, CDK6, and CAV1, which have been reported to enhance radioresistance. In addition, gene set enrichment analysis (GSEA) showed that the oxidative phosphorylation gene set was negatively enriched in HOXA1 high-expression samples in both HNSCC and LGG. Moreover, immunohistochemical assays indicated that high HOXA1 expression was significantly correlated with a high recurrence rate of nasopharyngeal carcinoma (NPC) after radiotherapy. Further in vitro experiments demonstrated that HOXA1 knockdown markedly attenuated the DNA repair capacity of NPC cells and sensibilized NPC cells to irradiation. Taken together, the results of this study demonstrate that HOXA1 has potential to be a predictive marker for radioresistance and post-radiotherapy prognosis that could help to guide individualized treatment in multiple cancer types.

HOXA1, a breast cancer oncogene

More than 25 years ago, the first literature records mentioned HOXA1 expression in human breast cancer. A few years later, HOXA1 was confirmed as a proper oncogene in mammary tissue. In the following two decades, molecular data about the mode of action of the HOXA1 protein, the factors contributing to activate and maintain HOXA1 gene expression and the identity of its target genes have accumulated and provide a wider view on the association of this transcription factor to breast oncogenesis. Large-scale transcriptomic data gathered from wide cohorts of patients further allowed refining the relationship between breast cancer type and HOXA1 expression. Several recent reports have reviewed the connection between cancer hallmarks and the biology of HOX genes in general. Here we take HOXA1 as a paradigm and propose an extensive overview of the molecular data centered on this oncoprotein, from what its expression modulators, to the interactors contributing to its oncogenic activities, and to the pathways and genes it controls. The data converge to an intricate picture that answers questions on the multi-modality of its oncogene activities, point towards better understanding of breast cancer aetiology and thereby provides an appraisal for treatment opportunities.

Hsa_circ_0074032 promotes prostate cancer progression through elevating homeobox A1 expression by serving as a microRNA-198 decoy

It has been reported that circular RNA hsa_circ_0074032 (circ_0074032) has a higher level in prostate cancer (PCa) tissues. However, the role and regulatory mechanism of circ_0074032 in PCa are still unknown. Circ_0074032 was overexpressed in PCa, and high circ_0074032 level was associated with worse PCa-related prognosis. Functionally, circ_0074032 silencing decreased xenograft tumour growth in vivo and induced cell apoptosis, curbed cell proliferation, migration and invasion in PCa cells in vitro. Furthermore, circ_0074032 was identified as a miR-198 decoy, and miR-198 inhibition abolished circ_0074032 silencing-mediated effects on PCa cell proliferation, apoptosis, migration and invasion. In addition, miR-198 directly targeted homeobox A1 (HOXA1), and HOXA1 weakened miR-198 mimic-mediated impacts on PCa cell malignant phenotypes. Importantly, circ_0074032 regulated HOXA1 expression by sponging miR-198. Our findings uncovered a novel mechanism by which circ_0074032 promoted PCa progression via elevating HOXA1 expression through acting as a miR-198 sponge, providing a mechanism for circ_0074032 to affect the development of PCa.

Molecular implications of HOX genes targeting multiple signaling pathways in cancer

Homeobox (HOX) genes encode highly conserved homeotic transcription factors that play a crucial role in organogenesis and tissue homeostasis. Their deregulation impacts the function of several regulatory molecules contributing to tumor initiation and progression. A functional bridge exists between altered gene expression of individual HOX genes and tumorigenesis. This review focuses on how deregulation in the HOX-associated signaling pathways contributes to the metastatic progression in cancer. We discuss their functional significance, clinical implications and ascertain their role as a diagnostic and prognostic biomarker in the various cancer types. Besides, the mechanism of understanding the theoretical underpinning that affects HOX-mediated therapy resistance in cancers has been outlined. The knowledge gained shall pave the way for newer insights into the treatment of cancer.

HOXA1 Is an Antagonist of ERα in Breast Cancer

Breast cancer is a heterogeneous disease and the leading cause of female cancer mortality worldwide. About 70% of breast cancers express ERα. HOX proteins are master regulators of embryo development which have emerged as being important players in oncogenesis. HOXA1 is one of them. Here, we present bioinformatic analyses of genome-wide mRNA expression profiles available in large public datasets of human breast cancer samples. We reveal an extremely strong opposite correlation between HOXA1 versus ER expression and that of 2,486 genes, thereby supporting a functional antagonism between HOXA1 and ERα. We also demonstrate in vitro that HOXA1 can inhibit ERα activity. This inhibition is at least bimodal, requiring an intact HOXA1 DNA-binding homeodomain and involving the DNA-binding independent capacity of HOXA1 to activate NF-κB. We provide evidence that the HOXA1-PBX interaction known to be critical for the transcriptional activity of HOXA1 is not involved in the ERα inhibition. Finally, we reveal that HOXA1 and ERα can physically interact but that this interaction is not essential for the HOXA1-mediated inhibition of ERα. Like other HOX oncoproteins interacting with ERα, HOXA1 could be involved in endocrine therapy resistance.

Identification of HOXA1 as a Novel Biomarker in Prognosis of Head and Neck Squamous Cell Carcinoma

Hox genes, a highly conserved homolog in most animals, play vital functions in cell development and organ formation. In recent years, researchers have discovered that it can act as a tumor regulator, and its members can participate in tumorigenesis by regulating receptor signaling, cell differentiation, apoptosis, migration, EMT, and angiogenesis. Hox genes and which major members play a vital role in the progress of head and neck squamous cell carcinoma (HNSCC) is still unclear. After analyzing the expression differences and prognostic value of all Hox genes through the TCGA-HNSC database, we use histochemistry stains in 52 pairs of HNSCC slices to verify the expression level of the key member-HOXA1. In correlation analysis, we found that high HOXA1 expression is related to poor pathological grade (p = 0.0077), advanced T stage (p = 0.021) and perineural invasion (PNI) (p = 0.0019). Furthermore, we used Cox univariate and multivariate regression analysis to confirm the independent predictive power of HOXA1 expression. To explore the underlying mechanisms behind HOXA1, we ran GSVA and GSEA and found fourteen mutual signaling pathways, including neuroprotein secretion and transport, tumor-associated signaling pathways, cell adhere junction and metabolic reprogramming. Finally, we found that the high expression of HOXA1 is significantly related to the decrease of CD8+ T cell infiltration and the decline of DNA methylation level. Our findings demonstrated that HOXA1, as a notable member of the HOX family, maybe an independent prognostic indicator in HNSCC.

HOX family transcription factors: Related signaling pathways and post-translational modifications in cancer

HOX family transcription factors belong to a highly conserved subgroup of the homeobox superfamily that determines cellular fates in embryonic morphogenesis and the maintenance of adult tissue architecture. HOX family transcription factors play key roles in numerous cellular processes including cell growth, differentiation, apoptosis, motility, and angiogenesis. As tumor promoters or suppressors HOX family members have been reported to be closely related with a variety of cancers. They closely regulate tumor initiation and growth, invasion and metastasis, angiogenesis, anti-cancer drug resistance and stem cell origin. Here, we firstly described the pivotal roles of HOX transcription factors in tumorigenesis. Then, we summarized the main signaling pathways regulated by HOX transcription factors, including Wnt/β-catenin, transforming growth factor β, mitogen-activated protein kinase, phosphoinositide 3-kinase/Akt, and nuclear factor-κB signalings. Finally, we outlined the important post-translational modifications of HOX transcription factors and their regulation in cancers. Future research directions on the HOX transcription factors are also discussed.

MicroRNA Profiling of Salivary Duct Carcinoma Versus Her2/Neu Overexpressing Breast Carcinoma Identify miR-10a as a Putative Breast Related Oncogene

Salivary duct carcinomas (SDC) and Her2/Neu3-overexpressing invasive breast carcinomas (HNPIBC/IBC) are histologically indistinguishable. We investigated whether common histopathologic and immunophenotypic features of SDC and IBC are mirrored by a similar microRNA (miRNA) profile. MiRNA profiling of 5 SDCs, 6 IBCs Her2/Neu3+, and 5 high-grade ductal breast carcinoma in situ (DCIS) was performed by NanoString platform. Selected miRNAs and HOXA1 gene were validated by RT-PCR. We observed similar miRNA expression profiles between IBC and SDC with the exception of 2 miRNAs, miR-10a and miR-142-3p, which were higher in IBC tumors. DCIS tumors displayed increased expression of miR-10a, miR-99a, miR-331-3p and miR-335, and decreased expression of miR-15a, miR-16 and miR-19b compared to SDC. The normal salivary gland and breast tissues also showed similar expression profiles. Interestingly, miR-10a was selectively increased in both IBC and normal breast tissue compared to SDC and normal salivary gland tissue. Moreover, our NanoString and RT-PCR data confirmed that miR-10a was upregulated in IBC and DCIS compared to SDC. Finally, we show downregulation of HOXA1, a miR-10 target, in IBC tumors compared to normal breast tissue. Taken together, our data demonstrates that, based on miRNA profiling, SDC is closely related to HNPIBC. Our results also suggest that miR-10a is differentially expressed in IBC compared to SDC and may have potential utility as a diagnostic biomarker in synchronous or metachronous malignant epithelial malignancies involving both organs. In addition, miR-10a could be playing an important role as a mammary-specific oncogene, involved in breast cancer initiation (DCIS) and progression (IBC), through mechanisms that include modulation of HOXA1 gene expression.

The O-GlcNAc transferase OGT interacts with and post-translationally modifies the transcription factor HOXA1

HOXA1 belongs to the HOX family of transcription factors which are key regulators of animal development. Little is known about the molecular pathways controlling HOXA1. Recent data from our group revealed distinct partner proteins interacting with HOXA1. Among them, OGT is an O-linked N-acetylglucosamine (O-GlcNAc) transferase modifying a variety of proteins involved in different cellular processes including transcription. Here, we confirm OGT as a HOXA1 interactor, we characterise which domains of HOXA1 and OGT are required for the interaction, and we provide evidence that OGT post-translationally modifies HOXA1. Mass spectrometry experiments indeed reveal that HOXA1 can be phosphorylated on the AGGTVGSPQYIHHSY peptide and that upon OGT expression, the phosphate adduct is replaced by an O-GlcNAc group.

PRDM14, a putative histone methyl-transferase, interacts with and decreases the stability and activity of the HOXA1 transcription factor

Understanding how the activity of transcription factors like HOX proteins is regulated remains a widely open question. In a recent screen for proteins interacting with HOXA1, we identified a PRDM protein family member, PRDM14, which is known to be transiently co-expressed with HOXA1 in epiblast cells before their specification towards somatic versus germ cell fate. Here, we confirm PRDM14 is an interactor of HOXA1 and we identify the homeodomain of HOXA1 as well as the PR domain and Zinc fingers of PRDM14 to be required for the interaction. An 11-His repeat of HOXA1 previously highlighted to contribute to HOXA1-mediated protein-protein interactions is also involved. At a functional level, we provide evidence that HOXA1 displays an unexpectedly long half-life and demonstrate that PRDM14 can reduce the stability and affect the transcriptional activity of HOXA1.

MicroRNA-433 Represses Proliferation and Invasion of Colon Cancer Cells by Targeting Homeobox A1

The aberrant expression of miR-433 has been validated in some types of cancers. However, the expression profile and the biological function of miR-433 on colon cancer are still elusive. This study was designed to investigate the function of miR-433 on the proliferation and invasion of colon cancer cells. We detected the expression of miR-433 in colon cancer tissues, adjacent normal tissues, and cell lines. CCK8 and Transwell assays were performed to explore the impact of miR-433 on colon cancer cell proliferation and invasion. The luciferase reporter assay was applied to identify the direct target of miR-433. The results demonstrated that miR-433 was downregulated in colon cancer tissues and cell lines when compared with the control. Overexpression of miR-433 significantly suppressed the ability of colon cancer cell proliferation and invasion, whereas knockdown of miR-433 remarkably enhanced cell proliferation and invasion. Homeobox A1 (HOXA1) was identified as a target of miR-433, and it mediated the functions of miR-433 on colon cancer cells. To conclude, we revealed that miR-433 was downregulated in colon cancer, and it inhibited colon cancer cell proliferation and invasion by directly targeting HOXA1.

Gene expression and adaptive noncoding changes during human evolution

Background

Despite evidence for adaptive changes in both gene expression and non-protein-coding, putatively regulatory regions of the genome during human evolution, the relationship between gene expression and adaptive changes in cis-regulatory regions remains unclear.

Results

Here we present new measurements of gene expression in five tissues of humans and chimpanzees, and use them to assess this relationship. We then compare our results with previous studies of adaptive noncoding changes, analyzing correlations at the level of gene ontology groups, in order to gain statistical power to detect correlations.

Conclusions

Consistent with previous studies, we find little correlation between gene expression and adaptive noncoding changes at the level of individual genes; however, we do find significant correlations at the level of biological function ontology groups. The types of function include processes regulated by specific transcription factors, responses to genetic or chemical perturbations, and differentiation of cell types within the immune system. Among functional categories co-enriched with both differential expression and noncoding adaptation, prominent themes include cancer, particularly epithelial cancers, and neural development and function.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-017-3831-2) contains supplementary material, which is available to authorized users.

Application of luteolin nanomicelles anti-glioma effect with improvement in vitro and in vivo

Glioblastoma multiforme (GBM) is one of the most common and malignant tumor. Luteolin, a polyphenolic compound, has been proposed to have anti-tumor activity against various cancers. However, the greatest obstacle in the administration of luteolin is its hydrophobicity as well as the low oral bioavailability. In this study, we formulated luteolin-loaded MPEG-PCL (Luteolin/MPEG-PCL) micelles aiming to improve its solubility in aqueous solution and investigate the anti-tumor effect on glioma in vitro and in vivo. The spherical Luteolin/MPEG-PCL micelles were completely dispersible in normal saline and could release luteolin in a sustained manner in vitro. We demonstrated that Luteolin/MPEG-PCL micelles had stronger cytotoxicity and induced a higher percentage of apoptosis in C6 and U87 cells than free luteolin in vitro. The immunohistochemical study revealed that Luteolin/MPEG-PCL micelles induced more glioma cell apoptosis than free luteolin and inhibited neovascularization in tumor tissues. The Pro-caspase9 and Bcl-2 down-regulation and cleaved-caspase9 and Bax up-regulation suggested that luteolin induced apoptosis via the mitochondrial pathway in vitro. What is more, we found the drug could cumulated much more in the nano-drug group than free drug group through imaging in vivo. In conclusion, the Luteolin/MPEG-PCL micelles have the potential clinical application in glioma chemotherapy.

The function of homeobox genes and lncRNAs in cancer

Recently, the homeobox (HOX) gene family has been reported as a factor in tumorigenesis. In the human genome, the HOX gene family contains 4 clusters with 39 genes and multiple transcripts. Mutation or abnormal expression of genes is responsible for developmental disorders. In addition, changes in the levels and activation of certain HOX genes has been associated with the development of cancer. Long non-coding RNAs (lncRNAs) have also been identified to serve critical functions in cancer. Although a limited number of lncRNAs have been previously investigated, the list of functional lncRNA genes has recently grown. Two of the most important and well-studied lncRNAs and HOX transcript genes are HOX transcript antisense RNA (HOTAIR) and HOXA distal transcript antisense RNA (HOTTIP). The present study aimed to review not only the function of the HOTAIR and HOTTIP genes in certain forms of cancer, but also to review other HOX genes and protein functions in cancer, particularly HOX family genes associated with lncRNAs.

HOXA1 binds RBCK1/HOIL-1 and TRAF2 and modulates the TNF/NF-κB pathway in a transcription-independent manner

HOX proteins define a family of key transcription factors regulating animal embryogenesis. HOX genes have also been linked to oncogenesis and HOXA1 has been described to be active in several cancers, including breast cancer. Through a proteome-wide interaction screening, we previously identified the TNFR-associated proteins RBCK1/HOIL-1 and TRAF2 as HOXA1 interactors suggesting that HOXA1 is functionally linked to the TNF/NF-κB signaling pathway. Here, we reveal a strong positive correlation between expression of HOXA1 and of members of the TNF/NF-κB pathway in breast tumor datasets. Functionally, we demonstrate that HOXA1 can activate NF-κB and operates upstream of the NF-κB inhibitor IκB. Consistently, we next demonstrate that the HOXA1-mediated activation of NF-κB is non-transcriptional and that RBCK1 and TRAF2 influences on NF-κB are epistatic to HOXA1. We also identify an 11 Histidine repeat and the homeodomain of HOXA1 to be required both for RBCK1 and TRAF2 interaction and NF-κB stimulation. Finally, we highlight that activation of NF-κB is crucial for HOXA1 oncogenic activity.

HOX transcription factors are potential targets and markers in malignant mesothelioma

BACKGROUND

The HOX genes are a family of homeodomain-containing transcription factors that determine cellular identity during development and which are dys-regulated in some cancers. In this study we examined the expression and oncogenic function of HOX genes in mesothelioma, a cancer arising from the pleura or peritoneum which is associated with exposure to asbestos.

METHODS

We tested the sensitivity of the mesothelioma-derived lines MSTO-211H, NCI-H28, NCI-H2052, and NCI-H226 to HXR9, a peptide antagonist of HOX protein binding to its PBX co-factor. Apoptosis was measured using a FACS-based assay with Annexin, and HOX gene expression profiles were established using RT-QPCR on RNA extracted from cell lines and primary mesotheliomas. The in vivo efficacy of HXR9 was tested in a mouse MSTO-211H flank tumor xenograft model.

RESULTS

We show that HOX genes are significantly dysregulated in malignant mesothelioma. Targeting HOX genes with HXR9 caused apoptotic cell death in all of the mesothelioma-derived cell lines, and prevented the growth of mesothelioma tumors in a mouse xenograft model. Furthermore, the sensitivity of these lines to HXR9 correlated with the relative expression of HOX genes that have either an oncogenic or tumor suppressive function in cancer. The analysis of HOX expression in primary mesothelioma tumors indicated that these cells could also be sensitive to the disruption of HOX activity by HXR9, and that the expression of HOXB4 is strongly associated with overall survival.

CONCLUSION

HOX genes are a potential therapeutic target in mesothelioma, and HOXB4 expression correlates with overall survival.

Elevated HOXA1 expression correlates with accelerated tumor cell proliferation and poor prognosis in gastric cancer partly via cyclin D1

BACKGROUND

HOXA1 is a member of the Homeobox gene family, which encodes a group of highly conserved transcription factors that are important in embryonic development. However, it has been reported that HOXA1 exhibits oncogenic properties in many malignancies. This study focused on the expression and clinical significance of HOXA1 in gastric cancer (GC).

METHODS

To assess the mRNA and protein expression of HOXA1 and cyclin D1 in GC tissues, we utilized qRT-PCR and western blotting, respectively. The effects of HOXA1 on GC cell proliferation, migration, and invasion, as well as xenograft tumor formation and the cell cycle were investigated in our established stable HOXA1 knockdown GC cell lines. The protein expression of HOXA1 and cyclin D1 was examined by immunohistochemistry using GC tissue microarrays (TMA) to analyze their relationship on a histological level. The Kaplan-Meier method and cox proportional hazards model were used to analyze the relationship of HOXA1 and cyclin D1 expression with GC clinical outcomes.

RESULTS

HOXA1 mRNA and protein expression were upregulated in GC tissues. Knockdown of HOXA1 in GC cells not only inhibited cell proliferation, migration, and invasion in vitro but also suppressed xenograft tumor formation in vivo. Moreover, HOXA1 knockdown induced changes in the cell cycle, and HOXA1 knockdown cells were arrested at the G1 phase, the number of cells in S phase was reduced, and the expression of cyclin D1 was decreased. In GC tissues, high cyclin D1 mRNA and protein expression were detected, and a significant correlation was found between the expression of HOXA1 and cyclin D1. Survival analysis indicated that HOXA1 and cyclin D1 expression were significantly associated with disease-free survival (DFS) and overall survival (OS). Interestingly, patients with tumors that were positive for HOXA1 and cyclin D1 expression showed worse prognosis. Multivariate analysis confirmed that the combination of HOXA1 and cyclin D1 was an independent prognostic indicator for OS and DFS.

CONCLUSION

Our data show that HOXA1 plays a crucial role in GC development and clinical prognosis. HOXA1, alone or combination with cyclin D1, may serve as a novel prognostic biomarker for GC.

Long noncoding RNA-HOTAIR affects chemoresistance by regulating HOXA1 methylation in small cell lung cancer cells

Homeobox (HOX) transcript antisense RNA (HOTAIR), a long intergenic noncoding RNA (lincRNA), has been reported to play an oncogenic role in various cancers including small cell lung cancer (SCLC). However, it is not known whether HOTAIR can modulate chemoresistance in SCLC. The aim of this study is to investigate the roles of HOTAIR in chemoresistance of SCLC and its possible molecular mechanism. Knockdown of HOTAIR was carried out in SCLC multidrug-resistant cell lines (H69AR and H446AR) and the parental cell lines (H69 and H446) to assess its influence on chemoresistance. The results showed that downregulation of HOTAIR increased cell sensitivity to anticancer drugs through increasing cell apoptosis and cell cycle arrest, and suppressed tumor growth in vivo. Moreover, HOXA1 methylation increased in the resistant cells using bisulfite sequencing PCR. Depletion of HOTAIR reduced HOXA1 methylation by decreasing DNMT1 and DNMT3b expression. The interaction between HOTAIR and HOXA1 was validated by RNA immunoprecipitation. Taken together, our study suggested that HOTAIR mediates chemoresistance of SCLC by regulating HOXA1 methylation and could be utilized as a potential target for new adjuvant therapies against chemoresistance.

Microarray and ChIP-seq data analysis revealed changes in p53-mediated transcriptional regulation in Nutlin-3-treated U2OS cells

Integrative analysis of chromatin immunoprecipitation-sequencing (ChIP-seq) data and microarray data was performed to illustrate the effect of Nutlin‑3 on promoter selectivity and transcriptional regulation by the tumor suppressor p53 in U2OS human osteosarcoma cells. Raw data (accession number, GSE46642) were downloaded from Gene Expression Omnibus. Differential analyses were performed using package limma of R software. Gene ontology enrichment and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses were performed for the differentially expressed genes (DEGs) using the Database for Annotation, Visualization and Integration Discovery. Integrative analysis of ChIP‑seq data and microarray data were confirmed with ChIP‑Array. A total of 565 DEGs were identified, including 373 upregulated genes and 192 downregulated genes. Genes involved in the p53 signaling pathway, cell cycle, DNA replication, cytokine‑cytokine receptor interaction and melanoma were markedly over‑represented in the DEGs. A total of 39 DEGs were directly regulated by p53 and two were the transcription factors (TFs), E2F2 and HOXA1. E2F2 regulated 25 DEGs, while HOXA1 regulated one DEG. The cell cycle, p53 signaling pathway, melanoma and pathways involved in cancer were enriched in the direct and indirect target genes. Changes in the p53‑binding pattern induced by Nutlin‑3 were described in the present study, which may advance the understanding of the regulatory network of p53 in osteosarcoma and aid in the development of novel therapies.

Families of microRNAs Expressed in Clusters Regulate Cell Signaling in Cervical Cancer

Tumor cells have developed advantages to acquire hallmarks of cancer like apoptosis resistance, increased proliferation, migration, and invasion through cell signaling pathway misregulation. The sequential activation of genes in a pathway is regulated by miRNAs. Loss or gain of miRNA expression could activate or repress a particular cell axis. It is well known that aberrant miRNA expression is well recognized as an important step in the development of cancer. Individual miRNA expression is reported without considering that miRNAs are grouped in clusters and may have similar functions, such as the case of clusters with anti-oncomiRs (23b~27b~24-1, miR-29a~29b-1, miR-29b-2~29c, miR-99a~125b-2, miR-99b~125a, miR-100~125b-1, miR-199a-2~214, and miR-302s) or oncomiRs activity (miR-1-1~133a-2, miR-1-2~133a-1, miR-133b~206, miR-17~92, miR-106a~363, miR183~96~182, miR-181a-1~181b-1, and miR-181a-2~181b-2), which regulated mitogen-activated protein kinases (MAPK), phosphatidylinositol-4,5-bisphosphate 3-kinase (PI3K), NOTCH, proteasome-culling rings, and apoptosis cell signaling. In this work we point out the pathways regulated by families of miRNAs grouped in 20 clusters involved in cervical cancer. Reviewing how miRNA families expressed in cluster-regulated cell path signaling will increase the knowledge of cervical cancer progression, providing important information for therapeutic, diagnostic, and prognostic methodology design.

Silencing HoxA1 by intraductal injection of siRNA lipidoid nanoparticles prevents mammary tumor progression in mice

With advances in screening, the incidence of detection of premalignant breast lesions has increased in recent decades; however, treatment options remain limited to surveillance or surgical removal by lumpectomy or mastectomy. We hypothesized that disease progression could be blocked by RNA interference (RNAi) therapy and set out to develop a targeted therapeutic delivery strategy. Using computational gene network modeling, we identified HoxA1 as a putative driver of early mammary cancer progression in transgenic C3(1)-SV40TAg mice. Silencing this gene in cultured mouse or human mammary tumor spheroids resulted in increased acinar lumen formation, reduced tumor cell proliferation, and restoration of normal epithelial polarization. When the HoxA1 gene was silenced in vivo via intraductal delivery of nanoparticle-formulated small interfering RNA (siRNA) through the nipple of transgenic mice with early-stage disease, mammary epithelial cell proliferation rates were suppressed, loss of estrogen and progesterone receptor expression was prevented, and tumor incidence was reduced by 75%. This approach that leverages new advances in systems biology and nanotechnology offers a novel noninvasive strategy to block breast cancer progression through targeted silencing of critical genes directly within the mammary epithelium.

Transcriptional suppression of miR-181c by hepatitis C virus enhances homeobox A1 expression

Hepatitis C virus (HCV)-induced chronic liver disease is one of the leading causes of hepatocellular carcinoma (HCC). The molecular events leading to HCC following chronic HCV infection remain poorly defined. MicroRNAs (miRNAs) have been implicated in the control of many biological processes, and their deregulation is associated with different viral infections. In this study, we observed that HCV infection of hepatocytes transcriptionally downregulates miR-181c expression by modulating CCAAT/enhancer binding protein β (C/EBP-β). Reduced expression of the pri-miR-181c transcript was noted following HCV infection. In silico prediction suggests that homeobox A1 (HOXA1) is a direct target of miR-181c. HOXA1 is a member of the homeodomain-containing transcription factor family and possesses pivotal roles in normal growth, development, and differentiation of mammalian tissues. Our results demonstrated that HOXA1 expression is enhanced in HCV-infected hepatocytes. Exogenous expression of the miR-181c mimic inhibits HOXA1 and its downstream molecules STAT3 and STAT5, which are involved in cell growth regulation. Interestingly, overexpression of miR-181c inhibited HCV replication by direct binding with E1 and NS5A sequences. Furthermore, accumulation of HCV genotype 2a RNA with miR-181c was observed in an RNA-induced silencing complex in Huh7.5 cells. Our results provide new mechanistic insights into the role of miR-181c in HCV-hepatocyte interactions, and miR-181c may act as a target for therapeutic intervention. Importance: Chronic HCV infection is one of the major causes of end-stage liver disease, including hepatocellular carcinoma. An understanding of the molecular mechanisms of HCV-mediated hepatocyte growth promotion is necessary for therapeutic intervention against HCC. In this study, we have provided evidence of HCV-mediated transcriptional downregulation of miR-181c. HCV-infected liver biopsy specimens also displayed lower expression levels of miR-181c. We have further demonstrated that inhibition of miR-181c upregulates homeobox A1 (HOXA1), which is important for hepatocyte growth promotion. Exogenous expression of miR-181c inhibited HCV replication by directly binding with HCV E1 and NS5A sequences. Taken together, our results provided new mechanistic insights for an understanding of the role of miR-181c in HCV-hepatocyte interactions and revealed miR-181c as a potential target for therapeutic intervention.

Cellular responses to hypoxia in the pulmonary circulation

Hypoxia can be defined as a reduction in available oxygen, whether in a whole organism or in a tissue or cell. It is a real life cause of pulmonary hypertension in humans both in terms of patients with chronic hypoxic lung disease and people living at high altitude. The effect of hypoxia on the pulmonary vasculature can be described in two ways; Hypoxic pulmonary vasoconstriction (HPV) (resulting from smooth muscle cell contraction) and pulmonary vascular remodelling (PVR) (resulting from pulmonary vascular cell proliferation). The pulmonary artery is made up of three resident cell types, the endothelial (intima), smooth muscle (media) and fibroblast (adventitia) cells. This review will examine the effects of hypoxia on the cells of the pulmonary vasculature and give an insight into the possible underlying mechanisms.

Elevated expression of miR-210 predicts poor survival of cancer patients: a systematic review and meta-analysis

BACKGROUND

MiRNAs are important regulators of different biological processes, including tumorigenesis. MiR-210 is a potential prognostic factor for survival in patients with cancer according to previous clinical researches. We conducted a systematic review and meta-analysis to summarize the significance of increased miR-210 expression in the prognosis of indicated cancers.

METHODOLOGY/PRINCIPAL FINDINGS

The present systematic review and meta-analysis of 16 researches included 1809 patients with 7 different types of cancers from 7 countries, and aimed to explore the association between miR-210 expression and the survival of cancer patients. Over-expression of miR-210 may predict poor overall survival (OS, HR = 1.33, 95% CI: 0.85-2.09, P = 0.210), but the effect was not significant. While the predictive effect on disease-free survival (DFS, HR = 1.89, 95% CI: 1.30-2.74, P = 0.001), progression-free survival (PFS, HR = 1.20, 95% CI: 1.05-1.38, P = 0.007) and relapse-free survival(RFS, HR = 4.42, 95% CI: 2.14-9.15, P = 0.000) for patients with breast cancer, primary head and neck squamous cell carcinoma (HNSCC), renal cancer, soft-tissue sarcoma, pediatric osteosarcoma, bladder cancer or glioblastoma was certain. Subgroup analysis showed the limited predictive effect of over-expressed miR-210 on breast cancer OS (HR = 1.63, 95% CI: 0.47-5.67, P = 0.443), breast cancer DFS (HR = 2.03, 95% CI: 0.90-4.57, P = 0.088), sarcoma OS (HR = 1.24, 95% CI: 0.20-7.89, P = 0.818) and renal cancer OS (HR = 1.16, 95% CI: 0.27-4.94, P = 0.842).

CONCLUSIONS/SIGNIFICANCE

This systematic review and meta-analysis suggests that miR-210 has a predictive effect on survival of patients with studied cancer types as indexed by disease-free survival, progression-free survival and relapse-free survival. While the predictive effect on overall survival, breast cancer overall survival, breast cancer disease-free survival, sarcoma overall survival and renal cancer overall survival was not statistically significant.

MicroRNA-99 family members suppress Homeobox A1 expression in epithelial cells

The miR-99 family is one of the evolutionarily most ancient microRNA families, and it plays a critical role in developmental timing and the maintenance of tissue identity. Recent studies, including reports from our group, suggested that the miR-99 family regulates various physiological processes in adult tissues, such as dermal wound healing, and a number of disease processes, including cancer. By combining 5 independent genome-wide expression profiling experiments, we identified a panel of 266 unique transcripts that were down-regulated in epithelial cells transfected with miR-99 family members. A comprehensive bioinformatics analysis using 12 different sequence-based microRNA target prediction algorithms revealed that 81 out of these 266 down-regulated transcripts are potential direct targets for the miR-99 family. Confirmation experiments and functional analyses were performed to further assess 6 selected miR-99 target genes, including mammalian Target of rapamycin (mTOR), Homeobox A1 (HOXA1), CTD small phosphatase-like (CTDSPL), N-myristoyltransferase 1 (NMT1), Transmembrane protein 30A (TMEM30A), and SWI/SNF-related matrix-associated actin-dependent regulator of chromatin subfamily A member 5 (SMARCA5). HOXA1 is a known proto-oncogene, and it also plays an important role in embryonic development. The direct targeting of the miR-99 family to two candidate binding sequences located in the HOXA1 mRNA was confirmed using a luciferase reporter gene assay and a ribonucleoprotein-immunoprecipitation (RIP-IP) assay. Ectopic transfection of miR-99 family reduced the expression of HOXA1, which, in consequence, down-regulated the expression of its downstream gene (i.e., Bcl-2) and led to reduced proliferation and cell migration, as well as enhanced apoptosis. In summary, we identified a number of high-confidence miR-99 family target genes, including proto-oncogene HOXA1, which may play an important role in regulating epithelial cell proliferation and migration during physiological disease processes, such as dermal wound healing and tumorigenesis.

Homeobox A7 stimulates breast cancer cell proliferation by up-regulating estrogen receptor-alpha

Breast cancer is the most common hormone-dependent malignancy in women. Homeobox (HOX) transcription factors regulate many cellular functions, including cell migration, proliferation and differentiation. The aberrant expression of HOX genes has been reported to be associated with human reproductive cancers. Estradiol (E2) and its nuclear receptors, estrogen receptor (ER)-alpha and ER-beta, are known to play critical roles in the regulation of breast cancer cell growth. However, an understanding of the potential relationship between HOXA7 and ER in breast cancer cells is limited. In this study, our results demonstrate that knockdown of HOXA7 in MCF7 cells significantly decreased cell proliferation and ERα expression. In addition, HOXA7 knockdown attenuated E2-induced cell proliferation as well as progesterone receptor (PR) expression. The stimulatory effects of E2 on cell proliferation and PR expression were abolished by co-treatment with ICI 182780, a selective ERα antagonist. In contrast, overexpression of HOXA7 significantly stimulated cell proliferation and ERα expression. Moreover, E2-induced cell proliferation, as well as PR expression, was enhanced by the overexpression of HOXA7. Neither knockdown nor overexpression of HOXA7 affected the ER-beta levels. Our results demonstrate a novel mechanistic role for HOXA7 in modulating breast cancer cell proliferation via regulation of ERα expression. This finding contributes to our understanding of the role HOXA7 plays in regulating the proliferation of ER-positive cancer cells.

Immediate early response gene X-1, a potential prognostic biomarker in cancers

INTRODUCTION

The immediate early response gene X-1 (IEX-1) plays a pivotal role in the regulation of cell apoptosis, proliferation, differentiation and metabolism. Deregulation of IEX-1 expression has been confirmed in multiple cancers in humans, in association with either poor or better prognosis depending on the type and progression stages of the cancer.

AREAS COVERED

This review summarizes clinical studies of altered IEX-1 expression in ovarian, pancreatic, blood, breast and colorectal cancers, lymphoma and myeloma. The authors also outline the current understandings of the complex functions of IEX-1 gained from studies with animal models and tumor cell lines so as to help us comprehend the significance of the clinical findings.

EXPERT OPINION

IEX-1 holds great promise to be a valuable biomarker, either alone or in combination with other genes, for monitoring progression of some cancers. IEX-1 expression is highly sensitive to environmental cues and distinct between normal and cancer cells. However, use of IEX-1 as a biomarker remains a significant challenge because too little is understood about the mechanism underlying the diverse activities of IEX-1 and a standardized clinical assay for IEX-1 detection and validation of clinical results across different studies are still critically lacking.

OxymiRs in cutaneous development, wound repair and regeneration

The state of tissue oxygenation is widely recognized as a major microenvironmental cue that is known to regulate the expression of coding genes. Recent works have extended that knowledge to demonstrate that the state of tissue oxygenation may potently regulate the expression of microRNAs (miRs). Collectively, such miRs that are implicated in defining biological outcomes in response to a change in the state of tissue oxygenation may be referred to as oxymiRs. Broadly, oxymiRs may be categorized into three groups: (A) the existence (expression and/or turnover) of which is directly influenced by changes in the state of tissue oxygenation; (B) the existence of which is indirectly (e.g. oxygen-sensitive proteins, metabolites, pH, etc.) influenced by changes in the state of tissue oxygenation; and (C) those that modify biological outcomes to changes in the state of tissue oxygenation by targeting oxygen sensing pathways. This work represents the first review of how oxymiRs may regulate development, repair and regeneration. Currently known oxymiRs may affect the functioning of a large number of coding genes which have hitherto fore never been linked to oxygen sensing. Many of such target genes have been validated and that number is steadily growing. Taken together, our understanding of oxymiRs has vastly expanded the implications of changes in the state of tissue oxygenation. This emerging paradigm has major implications in untangling the complexities underlying diseases associated with ischemia and related hypoxic insult such as chronic wounds.

The prolactin receptor mediates HOXA1-stimulated oncogenicity in mammary carcinoma cells

The HOX genes are a highly conserved subgroup of homeodomain-containing transcription factors that are crucial to normal development. Forced expression of HOXA1 results in oncogenic transformation of immortalized human mammary cells with aggressive tumour formation in vivo. Microarray analysis identified that the prolactin receptor (PRLR) was significantly upregulated by forced expression of HOXA1 in mammary carcinoma cells. To determine prolactin (PRL) involvement in HOXA1‑induced oncogenicity in mammary carcinoma cells (MCF-7), we examined the effect of human prolactin (hPRL)-initiated PRLR signal transduction on changes in cellular behaviour mediated by HOXA1. Forced expression of HOXA1 in MCF-7 cells increased PRLR mRNA and protein expression. Forced expression of HOXA1 also enhanced hPRL-stimulated phosphorylation of both STAT5A/B and p44/42 MAPK, and increased subsequent transcriptional activity of STAT5A and STAT5B, and Elk-1 and Sap1a, respectively. Moreover, forced expression of HOXA1 in MCF-7 cells enhanced the hPRL‑stimulated increase in total cell number as a consequence of enhanced cell proliferation and cell survival, and also enhanced hPRL-stimulated anchorage-independent growth in soft agar. Increased anchorage-independent growth was attenuated by the PRLR antagonist ∆1-9-G129R‑hPRL. In conclusion, we have demonstrated that HOXA1 increases expression of the cell surface receptor PRLR and enhances PRLR-mediated signal transduction. Thus, the PRLR is one mediator of HOXA1‑stimulated oncogenicity in mammary carcinoma cells.

Genome-wide aberrant DNA methylation of microRNA host genes in hepatocellular carcinoma

Mature microRNAs (miRNAs) are a class of small non-coding RNAs involved in posttranslational gene silencing. Previous studies found that downregulation of miRNAs is a common feature observed in solid tumors, including hepatocellular carcinoma (HCC). We employed a genome-wide approach to test the hypothesis that DNA methylation alterations in miRNA host genes may cause deregulated miRNA expression in HCC. We analyzed tumor and adjacent non-tumor tissues from 62 Taiwanese HCC cases using Infinium HumanMethylation27 DNA Analysis BeadChips that include 254 CpG sites covering 110 miRNAs from 64 host genes. Expression levels of three identified miRNAs (miR-10a, miR-10b and miR-196b) were measured in a subset of 37 HCC tumor and non-tumor tissues. After Bonferroni adjustment, a total of 54 CpG sites from 27 host genes significantly differed in DNA methylation levels between tumor and adjacent non-tumor tissues with 53 sites significantly hypermethylated in tumor tissues. Among the 54 significant CpG sites, 15 sites had more than 2-fold tumor/non-tumor changes, 17 sites had differences > 10%, and 10 sites had both features [including 8 significantly hypermethylated CpG sites in the host genes of miR-10a, miR-10b and miR-196b (HOXB4, HOXD4 and HOXA9, respectively)]. Significant downregulation of miR-10a was observed in tumor compared with non-tumor tissues (0.50 vs. 1.73, p = 0.031). The concordance for HOXB4 methylation alteration and dysregulation of miR-10a was 73.5%. No significant change was observed for miR-10b expression. Unexpectedly, miR-196b was significantly upregulated in tumor compared with non-tumor tissues (p = 0.0001). These data suggest that aberrant DNA methylation may lead to dysregulation of miR-10a in HCC tumor tissues.

The JmjC domain-containing histone demethylase KDM3A is a positive regulator of the G1/S transition in cancer cells via transcriptional regulation of the HOXA1 gene

A number of histone demethylases have been identified and biochemically characterized, yet their biological functions largely remain uncharacterized, particularly in the context of human diseases such as cancer. In this study, we describe important roles for the histone demethylase KDM3A, also known as JMJD1A, in human carcinogenesis. Expression levels of KDM3A were significantly elevated in human bladder carcinomas compared with nonneoplastic bladder tissues (p < 0.0001), when assessed by real-time PCR. We confirmed that some other cancers including lung cancer also overexpressed KDM3A, using cDNA microarray analysis. Treatment of cancer cell lines with small interfering RNA targeting KDM3A significantly knocked down its expression and resulted in the suppression of proliferation. Importantly, we found that KDM3A activates transcription of the HOXA1 gene through demethylating histone H3 at lysine 9 di-methylation by binding to its promoter region. Indeed, expression levels of KDM3A and HOXA1 in several types of cancer cell lines and bladder cancer samples were statistically correlated. We observed the down-regulation of HOXA1 as well as CCND1 after treatment with KDM3A siRNA, indicating G(1) arrest of cancer cells. Together, our results suggest that elevated expression of KDM3A plays a critical role in the growth of cancer cells, and further studies may reveal a cancer therapeutic potential in KDM3A inhibition.

miR-210: the master hypoxamir

MicroRNAs are small non-coding RNAs implicated mainly in post-transcriptional gene silencing by interacting with the untranslated region of the transcript. miR-210 represents major hypoxia-inducible miRs, also known as hypoxamirs, which is ubiquitously expressed in a wide range of cells, serving versatile functions. This review article summarizes the current progress on biogenesis of miR-210 and its physiological roles including arrest of cell proliferation, repression of mitochondrial respiration, arrest of DNA repair, vascular biology, and angiogenesis. Given the fact that miR-210 is aberrantly expressed in a number of diseases such as tumor progression, myocardial infarction and cutaneous ischemic wounds, miR-210 could serve as an excellent candidate for prognostic purposes and therapeutic intervention. With the advancement of computational prediction, high-throughput target validation methodology, sequencing, proteomic analysis, and microarray, it is anticipated that more down-stream targets of miR-210 and its associated biological consequences under hypoxia will be unveiled establishing miR-210 as a major hub in the biology of hypoxia-response.

HOXA1 is overexpressed in oral squamous cell carcinomas and its expression is correlated with poor prognosis

Background

HOX genes encode homeodomain-containing transcription factors involved in the regulation of cellular proliferation and differentiation during embryogenesis. However, members of this family demonstrated oncogenic properties in some malignancies. The present study investigated whether genes of the HOXA cluster play a role in oral cancer.

Methods

In order to identify differentially expressed HOXA genes, duplex RT-PCR in oral samples from healthy mucosa and squamous cell carcinoma was used. The effects of HOXA1 on proliferation, apoptosis, adhesion, invasion, epithelial-mesenchymal transition (EMT) and anchorage-independent growth were assessed in cells with up- and down-regulation of HOXA1. Immunohistochemical analysis using a tissue microarray (TMA) containing 127 oral squamous cell carcinomas (OSCC) was performed to determine the prognostic role of HOXA1 expression.

Results

We showed that transcripts of HOXA genes are more abundant in OSCC than in healthy oral mucosa. In particular, HOXA1, which has been described as one of the HOX members that plays an important role in tumorigenesis, was significantly more expressed in OSCCs compared to healthy oral mucosas. Further analysis demonstrated that overexpression of HOXA1 in HaCAT human epithelial cells promotes proliferation, whereas downregulation of HOXA1 in human OSCC cells (SCC9 cells) decreases it. Enforced HOXA1 expression in HaCAT cells was not capable of modulating other events related to tumorigenesis, including apoptosis, adhesion, invasion, EMT and anchorage-independent growth. A high number of HOXA1-positive cells was significantly associated with T stage, N stage, tumor differentiation and proliferative potential of the tumors, and was predictive of poor survival. In multivariate analysis, HOXA1 was an independent prognostic factor for OSCC patients (HR: 2.68; 95% CI: 1.59-2.97; p = 0.026).

Conclusion

Our findings indicate that HOXA1 may contribute to oral carcinogenesis by increasing tumor cell proliferation, and suggest that HOXA1 expression might be helpful as a prognostic marker for patients with OSCC.

The Pbx interaction motif of Hoxa1 is essential for its oncogenic activity

Hoxa1 belongs to the Hox family of homeodomain transcription factors involved in patterning embryonic territories and governing organogenetic processes. In addition to its developmental functions, Hoxa1 has been shown to be an oncogene and to be overexpressed in the mammary gland in response to a deregulation of the autocrine growth hormone. It has therefore been suggested that Hoxa1 plays a pivotal role in the process linking autocrine growth hormone misregulation and mammary carcinogenesis. Like most Hox proteins, Hoxa1 can interact with Pbx proteins. This interaction relies on a Hox hexapeptidic sequence centred on conserved Tryptophan and Methionine residues. To address the importance of the Hox-Pbx interaction for the oncogenic activity of Hoxa1, we characterized here the properties of a Hoxa1 variant with substituted residues in the hexapeptide and demonstrate that the Hoxa1 mutant lost its ability to stimulate cell proliferation, anchorage-independent cell growth, and loss of contact inhibition. Therefore, the hexapeptide motif of Hoxa1 is required to confer its oncogenic activity, supporting the view that this activity relies on the ability of Hoxa1 to interact with Pbx.

Extrapituitary growth hormone

Pituitary somatotrophs secrete growth hormone (GH) into the bloodstream, to act as a hormone at receptor sites in most, if not all, tissues. These endocrine actions of circulating GH are abolished after pituitary ablation or hypophysectomy, indicating its pituitary source. GH gene expression is, however, not confined to the pituitary gland, as it occurs in neural, immune, reproductive, alimentary, and respiratory tissues and in the integumentary, muscular, skeletal, and cardiovascular systems, in which GH may act locally rather than as an endocrine. These actions are likely to be involved in the proliferation and differentiation of cells and tissues prior to the ontogeny of the pituitary gland. They are also likely to complement the endocrine actions of GH and are likely to maintain them after pituitary senescence and the somatopause. Autocrine or paracrine actions of GH are, however, sometimes mediated through different signaling mechanisms to those mediating its endocrine actions and these may promote oncogenesis. Extrapituitary GH may thus be of physiological and pathophysiological significance.

Detection of breast cancer-related antigens through cDNA phage-displayed protein microarray

High-throughput molecular profiling techniques are helpful in the diagnosis of multifactorial disease. In this study, a cDNA-phage-displayed protein microarray using phage particles spotted directly onto it as sensors was used to detect related antigens in breast tumor sera. cDNA sequences from 17 positive clones were determined, which included some sequences encoding known breast cancer-related antigens and proteins related to other diseases, as well as proteins with unknown functions. Our results not only provide some useful information for breast cancer research, but also suggest that the strategy used here would be efficient to search for disease-related proteins and other functional target proteins.

Integrated gene networks in breast cancer development

Breast cancer is a complex and heterogenous disease. Classical molecular medical approaches cannot fully understand and comprehend its pathogenesis. In this review, the development of new biological markers for the early detection and creation of guided and specific therapy of breast cancer are discussed in light of the rapid advances in the "omics". Results of cancer research in combination with large-scale methods that examine the expression status of genes and proteins have identified a large number of new biomarkers as well as confirmed the human growth hormone as an important player in the pathogenesis of this disease through its autocrine regulation where it influences the activation of Pax5 and HOXA1 gene networks.

Characterization of mammary epithelial cell line HC11 using the NIA 15k gene array reveals potential regulators of the undifferentiated and differentiated phenotypes

Differentiation of undifferentiated mammary epithelial stem and/or progenitor cells results in the production of luminal-ductal and myoepithelial cells in the young animal and upon pregnancy, the production of luminal alveolar cells. A few key regulators of differentiation have been identified, though it is not known yet how these proteins function together to achieve their well-orchestrated products. In an effort to identify regulators of early differentiation, we screened the NIA 15k gene array of 15,247 developmentally expressed genes using mouse mammary epithelial HC11 cells as a model of differentiation. We have confirmed a number of genes preferentially expressed in the undifferentiated cells (Lgals1, Ran, Jam-A and Bmpr1a) and in those induced to undergo differentiation (Id1, Nfkbiz, Trib1, Rps21, Ier3). Using antibodies to the proteins encoded by Lgals1, and Jam-A, we confirmed that their proteins levels were higher in the undifferentiated cells. Although the amounts of bone morphogenetic protein receptor-1A (BMPR1A) protein were present at all stages, we found the activity of its downstream signal transduction pathway, as measured by the presence of phosphorylated-SMAD1, -SMAD5, and -SMAD8, is elevated in undifferentiated cells and decreases in fully differentiated cells. This evidence supports that the BMPR1A pathway functions primarily in undifferentiated mammary epithelial cells. We have identified a number of genes, of known and unknown function, that are candidates for the maintenance of the undifferentiated phenotype and for early regulators of mammary alveolar cell differentiation.

The truncated Hoxa1 protein interacts with Hoxa1 and Pbx1 in stem cells

Hox genes contain a homeobox encoding a 60-amino acid DNA binding sequence. The Hoxa1 gene (Hox1.6, ERA1) encodes two alternatively spliced mRNAs that encode distinct proteins, one with the homeodomain (Hoxa1-993), and another protein lacking this domain (Hoxa1-399). The functions of Hoxa1-399 are unknown. We detected Hoxa1-993 and Hoxa1-399 by immunoprecipitation using Hoxa1 antibodies. To assess whether Hoxa1-399 functions in cellular differentiation, we analyzed Hoxb1, a Hoxa1 target gene. Hoxa1-993 and its cofactor, Pbx1, bind to the Hoxb1 SOct-R3 promoter to transcriptionally activate a luciferase reporter. Results from F9 stem cells that stably express ectopic Hoxa1-399 (the F9-399 line) show that Hoxa1-399 reduces this transcriptional activation. Gel shift assays demonstrate that Hoxa1-399 reduces Hoxa1-993/Pbx1 binding to the Hoxb1 SOct-R3 region. GST pull-down experiments suggest that Hoxa1-399, Hoxa1-993, and Pbx1 form a trimer. However, the F9-399 line exhibits no differences in RA-induced proliferation arrest or endogenous Hoxb1, Pbx1, Hoxa5, Cyp26a1, GATA4, or Meis mRNA levels when compared to F9 wild-type.

Chemokine CXCL13 is overexpressed in the tumour tissue and in the peripheral blood of breast cancer patients

The abilities of chemokines in orchestrating cellular migration are utilised by different (patho-)biological networks including malignancies. However, except for CXCR4/CXCL12, little is known about the relation between tumour-related chemokine expression and the development and progression of solid tumours like breast cancer. In this study, microarray analyses revealed the overexpression of chemokine CXCL13 in breast cancer specimens. This finding was confirmed by real-time polymerase chain reaction in a larger set of samples (n=34) and cell lines, and was validated on the protein level performing Western blot, ELISA, and immunohistochemistry. Levels of CXCR5, the receptor for CXCL13, were low in malignant and healthy breast tissues, and surface expression was not detected in vitro. However, we observed a strong (P=0.0004) correlation between the expressions of CXCL13 and CXCR5 in breast cancer tissues, indicating a biologically relevant role of CXCR5 in vivo. Finally, we detected significantly elevated serum concentrations of CXCL13 in patients with metastatic disease (n=54) as compared with controls (n=44) and disease-free patients (n=48). In conclusion, CXCL13 is overexpressed within breast cancer tissues, and increased serum levels of this cytokine can be found in breast cancer patients with metastatic disease pointing to a role of CXCL13 in the progression of breast cancer, suggesting that CXCL13 might serve as a useful therapeutic target and/or diagnostic marker in this malignancy.

The EphA2 receptor and ephrinA1 ligand in solid tumors: function and therapeutic targeting

The Eph receptor tyrosine kinases and ephrin ligands have been studied extensively for their roles in developmental processes. In recent years, Eph receptors and ephrins have been found to be integral players in cancer formation and progression. Among these are EphA2 and ephrinA1, which are involved in the development and maintenance of many different types of solid tumors. The function of EphA2 and ephrinA1 in tumorigenesis and tumor progression is complex and seems to be dependent on cell type and microenvironment. These variables affect the expression of the EphA2 and ephrinA1 proteins, the pathways through which they induce signaling, and the functional consequences of that signaling on the behavior of tumor cells and tumor-associated cells. This review will specifically focus on the roles that EphA2 and ephrinA1 play in the different cell types that contribute to the malignancy of solid tumors, with emphasis on the opportunities for therapeutic targeting.

MicroRNA expression profiles and miR-10a target in anti-benzo[a] pyrene-7, 8-diol-9, 10-epoxide-transformed human 16HBE cells

OBJECTIVE

To screen miRNA profiles of malignantly transformed human bronchial epithelial cells, 16HBE-T, induced by anti-benzo[a]pyrene-trans-7,8-diol-9,10-epoxide (anti-BPDE), and to analyze putative miR-10a targets in 16HBE-T.

METHODS

A novel microarray platform was employed to screen miRNA profiles of 16HBE-T cells transformed by anti-BPDE. Microarray data for miR-10a and miR-320 were validated using quantitative real time polymerase chain reaction (QRT-PCR). The expression of a putative target for miR-10a, HOXA1, was analyzed by reverse transcription polymerase chain reaction (RT-PCR) and QRT-PCR.

RESULTS

In comparison with the vehicle-treated cells (16HBE-N), 16HBE-T exhibited differential expression of 54 miRNAs, in which, 45 were over-expressed and 9 were down-regulated. The five most highly expressed miRNAs were miR-494, miR-320, miR-498, miR-129, and miR-106a. The lowest expressed miRNAs were miR-10a, miR-493-5p, and miR-363*. Three members of miR-17-92 cluster, miR-17-5p, miR-20a, and miR-92, showed significantly higher abundance in 16BHE-T as miR-21, miR-141, miR-27a, miR-27b, miR-16 and miRNAs of the let-7 family. The putative target for miR-10a, HOXA1 mRNA was up-regulated 3-9-fold in 16HBE-T, as compared with 16HBE-N.

CONCLUSION

The findings of the study provide information on differentially expressed miRNA in malignant 16HBE-T, and also suggest a potential role of these miRNAs in cell transformation induced by anti-BPDE. HOXA1 is similarly up-regulated, suggesting that miR-10a is associated with the process of HOXA 1-mediated transformation.

Autocrine human growth hormone stimulates oncogenicity of endometrial carcinoma cells

Recent published data have demonstrated elevated levels of human GH (hGH) in endometriosis and endometrial adenocarcinoma. Herein, we demonstrate that autocrine production of hGH can enhance the in vitro and in vivo oncogenic potential of endometrial carcinoma cells. Forced expression of hGH in endometrial carcinoma cell lines RL95-2 and AN3 resulted in an increased total cell number through enhanced cell cycle progression and decreased apoptotic cell death. In addition, autocrine hGH expression in endometrial carcinoma cells promoted anchorage-independent growth and increased cell migration/invasion in vitro. In a xenograft model of human endometrial carcinoma, autocrine hGH enhanced tumor size and progression. Changes in endometrial carcinoma cell gene expression stimulated by autocrine hGH was consistent with the altered in vitro and in vivo behavior. Functional antagonism of hGH in wild-type RL95-2 cells significantly reduced cell proliferation, cell survival, and anchorage-independent cell growth. These studies demonstrate a functional role for autocrine hGH in the development and progression of endometrial carcinoma and indicate potential therapeutic relevance of hGH antagonism in the treatment of endometrial carcinoma.