The loss of Hoxa5 function causes estrous acyclicity and ovarian epithelial inclusion cysts

The Diversity of Methylation Patterns in Serous Borderline Ovarian Tumors and Serous Ovarian Carcinomas

Background: Changes in DNA methylation patterns are a pivotal mechanism of carcinogenesis. In some tumors, aberrant methylation precedes genetic changes, while gene expression may be more frequently modified due to methylation alterations than by mutations. Methods: Herein, 128 serous ovarian tumors were analyzed, including borderline ovarian tumors (BOTS) with (BOT.V600E) and without (BOT) the BRAF V600E mutation, low-grade (lg), and high-grade (hg) ovarian cancers (OvCa). The methylome of the samples was profiled with Infinium MethylationEPIC microarrays. Results: The biggest number of differentially methylated (DM) CpGs and regions (DMRs) was found between lgOvCa and hgOvCa. By contrast, the BOT.V600E tumors had the lowest number of DM CpGs and DMRs compared to all other groups and, in relation to BOT, their genome was strongly downmethylated. Remarkably, the ten most significant DMRs, discriminating BOT from lgOvCa, encompassed the MHC region on chromosome 6. We also identified hundreds of DMRs, being of potential use as predictive biomarkers in BOTS and hgOvCa. DMRs with the best discriminative capabilities overlapped the following genes: BAIAP3, IL34, WNT10A, NEU1, SLC44A4, and HMOX1, TCN2, PES1, RP1-56J10.8, ABR, NCAM1, RP11-629G13.1, AC006372.4, NPTXR in BOTS and hgOvCa, respectively. Conclusions: The global genome-wide hypomethylation positively correlates with the increasing aggressiveness of ovarian tumors. We also assume that the immune system may play a pivotal role in the transition from BOTS to lgOvCa. Given that the BOT.V600E tumors had the lowest number of DM CpGs and DMRs compared to all other groups, when methylome is considered, such tumors might be placed in-between BOT and OvCa.

Role of HOX genes in cancer progression and their therapeutical aspects

HOX genes constitute a family of evolutionarily conserved transcription factors that play pivotal roles in embryonic development, tissue patterning, and cell differentiation. These genes are essential for the precise spatial and temporal control of body axis formation in vertebrates. In addition to their developmental functions, HOX genes have garnered significant attention for their involvement in various diseases, including cancer. Deregulation of HOX gene expression has been observed in numerous malignancies, where they can influence tumorigenesis, progression, and therapeutic responses. This review provides an overview of the diverse roles of HOX genes in development, disease, and potential therapeutic targets, highlighting their significance in understanding biological processes and their potential clinical implications.

Regulation of progesterone receptor expression in endometriosis, endometrial cancer, and breast cancer by estrogen, polymorphisms, transcription factors, epigenetic alterations, and ubiquitin-proteasome system

The uterus and breasts are hormone-responsive tissues. Progesterone and estradiol regulate gonadotropin secretion, prepare the endometrium for implantation, maintain pregnancy, and regulate the differentiation of breast tissue. Dysregulation of these hormones causes endometriosis, endometrial cancer, and breast cancer, damaging the physical and mental health of women. Emerging evidence has shown that progesterone resistance or elevated progesterone activity is the primary hormonal substrate of these diseases. Since progesterone acts through its specific nuclear receptor, the abnormal expression of the progesterone receptor (PR) dysregulates progesterone function. This review discusses the regulatory mechanisms of PR expression in patients with endometriosis, and endometrial or breast cancer, including estrogen, polymorphisms, transcription factors, epigenetics, and the ubiquitin-proteasome system. (1) Estrogen promotes the expression of PRA (a PR isoform) mRNA and protein through the interaction of estrogen receptors (ERs) and Sp1 with half-ERE/Sp1 binding sites. ERs also affect the binding of Sp1 and Sp1 sites to promote the expression of PRB (another PR isoform)(2) PR polymorphisms, mainly PROGINS and + 331 G/A polymorphism, regulate PR expression by affecting DNA methylation and transcription factor binding. (3) The influence of epigenetic alterations on PR expression occurs through DNA methylation, histone modification, and microRNA. (4) As one of the main protein degradation pathways in vivo, the ubiquitin-proteasome system (UPS) regulates PR expression by participating in protein degradation. These mechanisms may provide new molecular targets for diagnosing and treating endometriosis, endometrial, and breast cancer.

HOXA5: A crucial transcriptional factor in cancer and a potential therapeutic target

HOX genes occupy a significant role in embryogenesis, hematopoiesis, and oncogenesis. HOXA5, a member of the A cluster of HOX genes, is essential for establishing the skeleton and normal organogenesis. As previously reported, aberrant HOXA5 expression contributes to anomalies and dysfunction of various organs, as well as affecting proliferation, differentiation, invasion, apoptosis, and other biological processes of tumor cells. Different cancers showed both downregulated and upregulated HOXA5 expression. The most common strategy for controlling HOXA5 downregulated expression may be CpG island hypermethylation. Additionally, current research demonstrated the regulatory network of HOXA5 and its connection with cancer stem cell progression and the immune microenvironment. Epigenetic modulators and upstream regulators, such as DNMTi and retinoic acid, may be beneficial for anti-tumor effects targeting HOXA5. Here, we summarize current knowledge about the HOXA5 gene, its role in various cancers, and its potential therapeutic value.

HINT1 (Histidine Triad Nucleotide-Binding Protein 1) Attenuates Cardiac Hypertrophy Via Suppressing HOXA5 (Homeobox A5) Expression

BACKGROUND

Cardiac hypertrophy is an important prepathology of, and will ultimately lead to, heart failure. However, the mechanisms underlying pathological cardiac hypertrophy remain largely unknown. This study aims to elucidate the effects and mechanisms of HINT1 (histidine triad nucleotide-binding protein 1) in cardiac hypertrophy and heart failure.

METHODS

HINT1 was downregulated in human hypertrophic heart samples compared with nonhypertrophic samples by mass spectrometry analysis. Hint1 knockout mice were challenged with transverse aortic constriction surgery. Cardiac-specific overexpression of HINT1 mice by intravenous injection of adeno-associated virus 9 (AAV9)-encoding Hint1 under the cTnT (cardiac troponin T) promoter were subjected to transverse aortic construction. Unbiased transcriptional analyses were used to identify the downstream targets of HINT1. AAV9 bearing shRNA against Hoxa5 (homeobox A5) was administrated to investigate whether the effects of HINT1 on cardiac hypertrophy were HOXA5-dependent. RNA sequencing analysis was performed to recapitulate possible changes in transcriptome profile.Coimmunoprecipitation assays and cellular fractionation analyses were conducted to examine the mechanism by which HINT1 regulates the expression of HOXA5.

RESULTS

The reduction of HINT1 expression was observed in the hearts of hypertrophic patients and pressure overloaded-induced hypertrophic mice, respectively. In Hint1-deficient mice, cardiac hypertrophy deteriorated after transverse aortic construction. Conversely, cardiac-specific overexpression of HINT1 alleviated cardiac hypertrophy and dysfunction. Unbiased profiler polymerase chain reaction array showed HOXA5 is 1 target for HINT1, and the cardioprotective role of HINT1 was abolished by HOXA5 knockdown in vivo. Hoxa5 was identified to affect hypertrophy through the TGF-β (transforming growth factor β) signal pathway. Mechanically, HINT1 inhibited PKCβ1 (protein kinase C β type 1) membrane translocation and phosphorylation via direct interaction, attenuating the MEK/ERK/YY1 (mitogen-activated protein kinase/extracellular signal-regulated kinase kinase/yin yang 1) signal pathway, downregulating HOXA5 expression, and eventually attenuating cardiac hypertrophy.

CONCLUSIONS

HINT1 protects against cardiac hypertrophy through suppressing HOXA5 expression. These findings indicate that HINT1 may be a potential target for therapeutic interventions in cardiac hypertrophy and heart failure.

Prevalence of endosalpingiosis and other benign gynecologic lesions

Endosalpingiosis, traditionally regarded as an incidental pathological finding, was recently reported to have an association with gynecologic malignancies. To determine the prevalence of endosalpingiosis, we evaluated all benign appearing adnexal lesions using the Sectioning and Extensively Examining-Fimbria (SEE-Fim) protocol, and queried the pathology database for the presence of endosalpingiosis, gynecologic malignancy, endometriosis, Walthard nests, and paratubal cysts. Using the SEE-Fim protocol, the prevalence of endosalpingiosis, endometriosis, Walthard nests, and paratubal cysts were 22%, 45%, 33%, and 42% respectively, substantially higher than previously reported. All lesions were observed to increase with age except endometriosis which increased until menopause then decreased dramatically. Among specimens including ovarian tissue, the prevalence of implantation of at least one lesion type was ubiquitous in patients age 51 and older (93%). The clinical significance of endosalpingiosis should be a continued area of research with larger trials assessing prevalence, factors affecting incidence, and association with malignancy. Our findings contribute to elucidating the origin of ectopic lesions and gynecologic disease risk.

Long Non-Coding RNA MAGI2-AS3 is a New Player with a Tumor Suppressive Role in High Grade Serous Ovarian Carcinoma

High-Grade Serous Ovarian Carcinoma (HGSC) is the most incidental and lethal subtype of epithelial ovarian cancer (EOC) with a high mortality rate of nearly 65%. Recent findings aimed at understanding the pathogenesis of HGSC have attributed its principal source as the Fallopian Tube (FT). To further comprehend the exact mechanism of carcinogenesis, which is still less known, we performed a transcriptome analysis comparing FT and HGSC. Our study aims at exploring new players involved in the development of HGSC from FT, along with their signaling network, and we chose to focus on non-coding RNAs. Non-coding RNAs (ncRNAs) are increasingly observed to be the major regulators of several cellular processes and could have key functions as biological markers, as well as even a therapeutic approach. The most physiologically relevant and significantly dysregulated non-coding RNAs were identified bioinformatically. After analyzing the trend in HGSC and other cancers, MAGI2-AS3 was observed to be an important player in EOC. We assessed its tumor-suppressive role in EOC by means of various assays. Further, we mapped its signaling pathway using its role as a miRNA sponge to predict the miRNAs binding to MAGI2AS3 and showed it experimentally. We conclude that MAGI2-AS3 acts as a tumor suppressor in EOC, specifically in HGSC by sponging miR-15-5p, miR-374a-5p and miR-374b-5p, and altering downstream signaling of certain mRNAs through a ceRNA network.

Lineage tracing suggests that ovarian endosalpingiosis does not result from escape of oviductal epithelium

Most high-grade serous carcinomas are thought to arise from Fallopian tube epithelium (FTE), but some likely arise outside of the tube, perhaps from ectopic tubal-type epithelium known as endosalpingiosis. Importantly, the origin of endosalpingiosis is poorly understood. The proximity of the tubal fimbriae to the ovaries has led to the proposal that disruptions in the ovarian surface that occur during ovulation may allow detached FTE to implant in the ovary and form tubal-type glands and cysts. An alternative model suggests that cells present in ectopic locations outside the Müllerian tract retain the capacity for multi-lineage differentiation and can form glands with tubal-type epithelium. We used double transgenic Ovgp1-iCreER^T2 ;R26R^LSL-eYFP mice, which express an eYFP reporter protein in OVGP1-positive tissues following transient tamoxifen (TAM) treatment, to track the fate of oviductal epithelial cells. Cohorts of adult mice were given TAM to activate eYFP expression in oviductal epithelium, and ovaries were examined at time points ranging from 2 days to 12 months post-TAM. To test whether superovulation might increase acquisition of endosalpingiosis, additional cohorts of TAM-treated mice underwent up to five cycles of superovulation and ovaries were examined at 1, 6, and 12 months post-TAM. Ovaries were sectioned in their entirety to identify endosalpingiosis. Immunohistochemical staining for PAX8, tubulin, OVGP1, and eYFP was employed to study endosalpingiosis lesions. Ovarian endosalpingiosis was identified in 14.2% of TAM-treated adult mice. The endosalpingiotic inclusion glands and cysts were lined by secretory and ciliated cells and expressed PAX8, tubulin, OVGP1, and eYFP. Neither age nor superovulation was associated with a significant increase in endosalpingiosis. Endosalpingiosis was also occasionally present in the ovaries of pre-pubertal mice. The findings imply that ovarian endosalpingiosis in the mouse does not likely arise as a consequence of detachment and implantation of tubal epithelium and other mechanisms may be relevant. © 2019 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Lowly-expressed lncRNA GAS5 facilitates progression of ovarian cancer through targeting miR-196-5p and thereby regulating HOXA5

PURPOSE

This investigation was aimed at extrapolating whether and how lncRNA GAS5, miR-196a-5p and HOXA5 altered progression of ovarian cancer (OA).

METHOD

Totally 195 pairs of OA tissues and adjacent normal tissues were collected. Also si-GAS5, pcDNA-GAS5, miR-196a-5p mimic, miR-196a-5p inhibitor and negative control (NC) were, respectively, transfected into OA cells. Besides, dual-luciferase reporter gene assay was performed to validate the targeted relationships between GAS5 and miR-196a-5p, as well as between miR-196a-5p and HOXA5. The impacts of GAS5, miR-196a-5p and HOXA5 on viability, proliferation and apoptosis of OA cells were appraised via conduction of colony formation assay, MTT assay and flow cytometry assay.

RESULT

Lower GAS5 expression and higher miR-196a-5p expression were associated with larger tumor size (≥5 cm) and more advanced FIGO stage (III-IV) of OA patients (P < 0.05). Transfection of si-GAS5, miR-196a-5p mimic or si-HOXA5 conferred OA cells with stronger viability, faster proliferation and smaller percentage of apoptosis (P < 0.05). After injecting mice models with si-GAS5, miR-196a-5p mimic or si-HOXA5, a larger tumor size was also observed within the rats (P < 0.05). GAS5 was indicated to directly target miR-196a-5p and modify its expression, and the targeted relationship also seemed to exist between miR-196a-5p and HOXA5 (P < 0.05). The HOXA5 was found to reverse the effects imposed by miR-196a-5p on viability, proliferation and apoptosis of OA cells (P < 0.05).

CONCLUSION

LncRNA GAS5 depressed OA development by targeting miR-196a-5p and thereby down-regulating HOXA5 expression, providing substance for developing lncRNA-based strategies to treat OA.

Early transcriptional response of human ovarian and fallopian tube surface epithelial cells to norepinephrine

Evidence from human and animal studies suggests that chronic behavioral stress and resulting activation of the sympathetic nervous system may influence initiation and progression of tumors. However, the underlying mechanisms for these observations are poorly understood. The purpose of this study is to explore the effects of adrenergic signaling on cell line models derived from normal cells presumed to originate epithelial ovarian cancers. Here we explored the effects of the stress-related hormone, norepinephrine, on the transcriptional program of normal immortalized ovarian (iOSE) and fallopian tube (iFTSEC) surface epithelial cells. Analysis of RNA-Seq data of treated and untreated cells revealed a significant overlap between the responses in iOSE and iFTSEC cells. Most genes modulated by norepinephrine in ovarian and fallopian tube epithelial cells are already expressed in normal ovarian and fallopian tissue and cells. For several genes, expression changes were reflected at the protein level. Genes in immune-related and developmental pathways were enriched in the set of genes modulated by norepinephrine. We identified HOXA5, SPIB, REL, SRF, SP1, NFKB1, MEF2A, E2F1, and EGR1 transcription factor binding sites to be highly enriched in our dataset. These data represent the early transcriptional response to norepinephrine in cells postulated to originate epithelial ovarian cancer.

Lung development requires an active ERK/MAPK pathway in the lung mesenchyme

BACKGROUND

Reciprocal epithelial-mesenchymal communications are critical throughout lung development, dictating branching morphogenesis and cell specification. Numerous signaling molecules are involved in these interactions, but the way epithelial-mesenchymal crosstalk is coordinated remains unclear. The ERK/MAPK pathway transduces several important signals in lung formation. Epithelial inactivation of both Mek genes, encoding ERK/MAPK kinases, causes lung agenesis and death. Conversely, Mek mutation in mesenchyme results in lung hypoplasia, trachea cartilage malformations, kyphosis, omphalocele, and death. Considering the negative impact of kyphosis and omphalocele on intrathoracic space and, consequently, on lung growth, the exact role of ERK/MAPK pathway in lung mesenchyme remains unresolved.

RESULTS

To address the role of the ERK/MAPK pathway in lung mesenchyme in absence of kyphosis and omphalocele, we used the Tbx4^Cre deleter mouse line, which acts specifically in lung mesenchyme. These Mek mutants did not develop kyphosis and omphalocele but they presented lung hypoplasia, tracheal defects, and neonatal death. Tracheal cartilage anomalies suggested a role for the ERK/MAPK pathway in the control of chondrocyte hypertrophy. Moreover, expression data indicated potential interactions between the ERK/MAPK and canonical Wnt pathways during lung formation.

CONCLUSIONS

Lung development necessitates a functional ERK/MAPK pathway in the lung mesenchymal layer in order to coordinate efficient epithelial-mesenchymal interactions. Developmental Dynamics 246:72-82, 2017. © 2016 Wiley Periodicals, Inc.

Hoxa5: A Key Player in Development and Disease

A critical position in the developmental hierarchy is occupied by the Hox genes, which encode transcription factors. Hox genes are crucial in specifying regional identity along the embryonic axes and in regulating morphogenesis. In mouse, targeted mutations of Hox genes cause skeletal transformations and organ defects that can impair viability. Here, we present the current knowledge about the Hoxa5 gene, a paradigm for the function and the regulation of Hox genes. The phenotypic survey of Hoxa5-/- mice has unveiled its critical role in the regional specification of the skeleton and in organogenesis. Most Hoxa5-/- mice die at birth from respiratory distress due to tracheal and lung dysmorphogenesis and impaired diaphragm innervation. The severity of the phenotype establishes that Hoxa5 plays a predominant role in lung organogenesis versus other Hox genes. Hoxa5 also governs digestive tract morphogenesis, thyroid and mammary glands development, and ovary homeostasis. Deregulated Hoxa5 expression is reported in cancers, indicating Hoxa5 involvement in tumor predisposition and progression. The dynamic Hoxa5 expression profile is under the transcriptional control of multiple cis-acting sequences and trans-acting regulators. It is also modulated by epigenetic mechanisms, implicating chromatin modifications and microRNAs. Finally, lncRNAs originating from alternative splicing and distal promoters encompass the Hoxa5 locus.

Verifying the markers of ovarian cancer using RNA-seq data

Markers associated with diagnosis, presentation and potential therapeutic targets have received widespread attention in ovarian cancer research in the past few years. However, the majority of these markers have been investigated individually, and the changes in expression and the association between them are rarely documented. Next‑generation sequencing, also termed RNA-seq when the sequencing targets are cDNAs, can provide a whole blueprint of the transcriptome of a specific tissue. In the present study, RNA-seq data of human ovarian cancer samples were used to verify the expression of known markers and to identify the association between them. A total of 563 markers associated with ovarian cancer were retrieved from the database of the National Center of Biotechnology Information, and used as the target markers. The transcriptome of the ovarian tissue of four different tumors, containing tumor presentation and recurrence stages, were sequenced using the Illumina GAII platform. Approximately 85.97% markers were expressed of the total 563 markers, and the majority of them were involved in pathways associated with cancer, signaling and infection. In total, 85 markers were found to be aberrantly expressed in tumor cells from patients with ovarian cancer who had recurrences, including 33 upregulated markers at the recurrence stage. Therefore, they may have roles ovarian tumor due to their aberrant expression. Differentially expressed markers and the associations between them can be assessed by examining the RNA-seq data. These findings may provide novel information for further studies on ovarian cancer.

HOX genes and their role in the development of human cancers

In this review, we summarize published findings on the involvement of HOX genes in oncogenesis. HOX genes are developmental genes--they code for proteins that function as critical master regulatory transcription factors during embryogenesis. Many reports have shown that the protein products of HOX genes also play key roles in the development of cancers. Based on our review of the literature, we found that the expression of HOX genes is not only up- or downregulated in most solid tumors but also that the expression of specific HOX genes in cancers tends to differ based on tissue type and tumor site. It was also observed that HOXC family gene expression is upregulated in most solid tumor types, including colon, lung, and prostate cancer. The two HOX genes that were reported to be most commonly altered in solid tumors were HOXA9 and HOXB13. HOXA were often reported to have altered expression in breast and ovarian cancers, HOXB genes in colon cancers, HOXC genes in prostate and lung cancers, and HOXD genes in colon and breast cancers. It was found that HOX genes are also regulated at the nuclear-cytoplasmic transport level in carcinomas. Tumors arising from tissue having similar embryonic origin (endodermal), including colon, prostate, and lung, showed relatively similar HOXA and HOXB family gene expression patterns compared to breast tumors arising from mammary tissue, which originates from the ectoderm. The differential expression of HOX genes in various solid tumors thus provides an opportunity to advance our understanding of cancer development and to develop new therapeutic agents.

YY1 acts as a transcriptional activator of Hoxa5 gene expression in mouse organogenesis

The Hox gene family encodes homeodomain-containing transcriptional regulators that confer positional information to axial and paraxial tissues in the developing embryo. The dynamic Hox gene expression pattern requires mechanisms that differentially control Hox transcription in a precise spatio-temporal fashion. This implies an integrated regulation of neighbouring Hox genes achieved through the sharing and the selective use of defined enhancer sequences. The Hoxa5 gene plays a crucial role in lung and gut organogenesis. To position Hoxa5 in the regulatory hierarchy that drives organ morphogenesis, we searched for cis-acting regulatory sequences and associated trans-acting factors required for Hoxa5 expression in the developing lung and gut. Using mouse transgenesis, we identified two DNA regions included in a 1.5-kb XbaI-XbaI fragment located in the Hoxa4-Hoxa5 intergenic domain and known to control Hoxa4 organ expression. The multifunctional YY1 transcription factor binds the two regulatory sequences in vitro and in vivo. Moreover, the mesenchymal deletion of the Yy1 gene function in mice results in a Hoxa5-like lung phenotype with decreased Hoxa5 and Hoxa4 gene expression. Thus, YY1 acts as a positive regulator of Hoxa5 expression in the developing lung and gut. Our data also support a role for YY1 in the coordinated expression of Hox genes for correct organogenesis.

Hoxa5/Cre transgenic mice: novel tools for regional deletion along the anterior-posterior axis

The Hoxa5 homeobox gene encodes a transcription factor that plays a critical role in specifying the identity of the cervico-thoracic region along the anterior-posterior embryo axis and in orchestrating organ morphogenesis. The loss of Hoxa5 function results in skeletal transformations, lethality at birth due to lung defects, and organ anomalies affecting the digestive tract, the mammary gland and the ovary. Study of Hoxa5 gene regulation has revealed the interplay of several control regions that direct Hoxa5 developmental expression. Enhancers targeting expression in the CNS, the paraxial and lateral plate mesoderm at the cervico-thoracic level, and in the mesenchymal compartment of the respiratory and digestive tracts have been identified. Using these molecular tools, we have generated two Hoxa5/Cre transgenic mouse lines carrying different combinations of Hoxa5 regulatory enhancers and allowing site-specific recombination in subsets of Hoxa5 expression sites as tested with the Rosa26/lacZ reporter mice. Further validation of the recombination efficiency of the Hoxa5/Cre transgenic lines was performed with mice carrying a Hoxa5 conditional allele. Hoxa5 deletion with the Hoxa5/Cre mouse lines recapitulates Hoxa5 mutant phenotypes, such as skeletal defects, neonatal lethality, and lung malformations. Hoxa5/Cre mouse lines provide novel genetic tools for gene function analysis in defined tissues along the anterior-posterior axis.

Partial functional redundancy between Hoxa5 and Hoxb5 paralog genes during lung morphogenesis

Hox genes encode transcription factors governing complex developmental processes in several organs. A subset of Hox genes are expressed in the developing lung. Except for Hoxa5, the lack of overt lung phenotype in single mutants suggests that Hox genes may not play a predominant role in lung ontogeny or that functional redundancy may mask anomalies. In the Hox5 paralog group, both Hoxa5 and Hoxb5 genes are expressed in the lung mesenchyme whereas Hoxa5 is also expressed in the tracheal mesenchyme. Herein, we generated Hoxa5;Hoxb5 compound mutant mice to evaluate the relative contribution of each gene to lung development. Hoxa5;Hoxb5 mutants carrying the four mutated alleles displayed an aggravated lung phenotype, resulting in the death of the mutant pups at birth. Characterization of the phenotype highlighted the role of Hoxb5 in lung formation, the latter being involved in branching morphogenesis, goblet cell specification, and postnatal air space structure, revealing partial functional redundancy with Hoxa5. However, the Hoxb5 lung phenotypes were less severe than those seen in Hoxa5 mutants, likely because of Hoxa5 compensation. New specific roles for Hoxa5 were also unveiled, demonstrating the extensive contribution of Hoxa5 to the developing respiratory system. The exclusive expression of Hoxa5 in the trachea and the phrenic motor column likely underlies the Hoxa5-specific trachea and diaphragm phenotypes. Altogether, our observations establish that the Hoxa5 and Hoxb5 paralog genes shared some functions during lung morphogenesis, Hoxa5 playing a predominant role.

Technical challenges and limitations of current mouse models of ovarian cancer

The development of genetically engineered models (GEM) of epithelial ovarian cancer (EOC) has been very successful, with well validated models representing high grade and low grade serous adenocarcinomas and endometrioid carcinoma (EC). Most of these models were developed using technologies intended to target the ovarian surface epithelium (OSE), the cell type long believed to be the origin of EOC. More recent evidence has highlighted what is likely a more prevalent role of the secretory cell of the fallopian tube in the ontogeny of EOC, however none of the GEM of EOC have demonstrated successful targeting of this important cell type.

The precise technologies exploited to develop the existing GEM of EOC are varied and carry with them advantages and disadvantages. The use of tissue specific promoters to model disease has been very successful, but the lack of any truly specific OSE or oviductal secretory cell promoters makes the outcomes of these models quite unpredictable. Effecting genetic change by the administration of adenoviral vectors expressing Cre recombinase may alleviate the perceived need for tissue specific promoters, however the efficiencies of infection of different cell types is subject to numerous biological parameters that may lead to preferential targeting of certain cell populations.

One important future avenue of GEM of EOC is the evaluation of the role of genetic modifiers. We have found that genetic background can lead to contrasting phenotypes in one model of ovarian cancer, and data from other laboratories have also hinted that the exact genetic background of the model may influence the resulting phenotype. The different genetic backgrounds may modify the biology of the tumors in a manner that will be relevant to human disease, but they may also be modifying parameters which impact the response of the host to the technologies employed to develop the model.

RanBPM expression regulates transcriptional pathways involved in development and tumorigenesis

RanBPM is a ubiquitous protein that has been reported to regulate several cellular processes through interactions with various proteins. However, it is not known whether RanBPM may regulate gene expression patterns. As it has been shown that RanBPM interacts with a number of transcription factors, we hypothesized that it may have wide ranging effects on gene expression that may explain its function. To test this hypothesis, we generated stable RanBPM shRNA cell lines to analyze the effect of RanBPM on global gene expression. Microarray analyses were conducted comparing the gene expression profile of Hela and HCT116 RanBPM shRNA cells versus control shRNA cells. We identified 167 annotated genes significantly up- or down-regulated in the two cell lines. Analysis of the gene set revealed that down-regulation of RanBPM led to gene expression changes that affect regulation of cell, tissue, and organ development and morphology, as well as biological processes implicated in tumorigenesis. Analysis of Transcription Factor Binding Sites (TFBS) present in the gene set identified several significantly over-represented transcription factors of the Forkhead, HMG, and Homeodomain families of transcription factors, which have previously been demonstrated as having important roles in development and tumorigenesis. In addition, the combined results of these analyses suggested that several signaling pathways were affected by RanBPM down-regulation, including ERK1/2, Wnt, Notch, and PI3K/Akt pathways. Lastly, analysis of selected target genes by quantitative RT-qPCR confirmed the changes revealed by microarray. Several of the genes up-regulated in RanBPM shRNA cells encode proteins with known oncogenic functions, such as the RON tyrosine kinase, the adhesion molecule L1CAM, and transcription factor ELF3/ESE-1, suggesting that RanBPM functions as a tumor suppressor to prevent deregulated expression of these genes. Altogether, these results suggest that RanBPM does indeed function to regulate many genomic events that regulate embryonic, tissue, and cellular development as well as those involved in cancer development and progression.

Ovarian cancer stroma: pathophysiology and the roles in cancer development

Ovarian cancer represents one of the cancers with the worst prognostic in adult women. More than half of the patients who present with clinical signs such as abdominal bloating and a feeling of fullness already show advanced stages. The majority of ovarian cancers grow as cystic masses, and cancer cells easily spread into the pelvic cavity once the cysts rupture or leak. When the ovarian cancer cells disseminate into the peritoneal cavity, metastatic nests may grow in the cul-de-sac, and in more advanced stages, the peritoneal surfaces of the upper abdomen become the next largest soil for cancer progression. Ascites is also produced frequently in ovarian cancers, which facilitates distant metastasis. Clinicopathologic, epidemiologic and molecular studies on ovarian cancers have improved our understanding and therapeutic approaches, but still further efforts are required to reduce the risks in the patients who are predisposed to this lethal disease and the mortality of the patients in advanced stages. Among various molecules involved in ovarian carcinogenesis, special genes such as TP53, BRCA1 and BRCA2 have been well investigated. These genes are widely accepted as the predisposing factors that trigger malignant transformation of the epithelial cells of the ovary. In addition, adnexal inflammatory conditions such as chronic salpingitis and ovarian endometriosis have been great research interests in the context of carcinogenic background of ovarian cancers. In this review, I discuss the roles of stromal cells and inflammatory factors in the carcinogenesis and progression of ovarian cancers.

The loss of Hoxa5 function promotes Notch-dependent goblet cell metaplasia in lung airways

Hox genes encode transcription factors controlling complex developmental processes in various organs. Little is known, however, about how HOX proteins control cell fate. Herein, we demonstrate that the goblet cell metaplasia observed in lung airways from Hoxa5^−/− mice originates from the transdifferentiation of Clara cells. Reduced CC10 expression in Hoxa5^−/− embryos indicates that altered cell specification occurs prior to birth. The loss of Hoxa5 function does not preclude airway repair after naphthalene exposure, but the regenerated epithelium presents goblet cell metaplasia and less CC10-positive cells, demonstrating the essential role of Hoxa5 for correct differentiation. Goblet cell metaplasia in Hoxa5^−/− mice is a FOXA2-independent process. However, it is associated with increased Notch signaling activity. Consistent with these findings, expression levels of activated NOTCH1 and the effector gene HEY2 are enhanced in patients with chronic obstructive pulmonary disease. In vivo administration of a γ-secretase inhibitor attenuates goblet cell metaplasia in Hoxa5^−/− mice, highlighting the contribution of Notch signaling to the phenotype and suggesting a potential therapeutic strategy to inhibit goblet cell differentiation and mucus overproduction in airway diseases. In summary, the loss of Hoxa5 function in lung mesenchyme impacts on epithelial cell fate by modulating Notch signaling.