Androgen-regulated transcription factor AIbZIP in prostate cancer

Regulatory mechanisms of the cAMP-responsive element binding protein 3 (CREB3) family in cancers

The CREB3 family of proteins, encompassing CREB3 and its four homologs (CREB3L1, CREB3L2, CREB3L3, and CREB3L4), exerts pivotal control over cellular protein metabolism in response to unfolded protein reactions. Under conditions of endoplasmic reticulum stress, activation of the CREB3 family occurs through regulated intramembrane proteolysis within the endoplasmic reticulum membrane. Perturbations in the function and expression of the CREB3 family have been closely associated with the development of diverse diseases, with a particular emphasis on cancer. Recent investigations have shed light on the indispensable role played by CREB3 family members in modulating the onset and progression of various human cancers. This comprehensive review endeavors to provide an in-depth examination of the involvement of CREB3 family members in distinct human cancer types, accentuating their significance in the pathogenesis of cancer and the manifestation of malignant phenotypes.

Identifying proteomic risk factors for overall, aggressive and early onset prostate cancer using Mendelian randomization and tumor spatial transcriptomics

Background

Understanding the role of circulating proteins in prostate cancer risk can reveal key biological pathways and identify novel targets for cancer prevention.

Methods

We investigated the association of 2,002 genetically predicted circulating protein levels with risk of prostate cancer overall, and of aggressive and early onset disease, using cis-pQTL Mendelian randomization (MR) and colocalization. Findings for proteins with support from both MR, after correction for multiple-testing, and colocalization were replicated using two independent cancer GWAS, one of European and one of African ancestry. Proteins with evidence of prostate-specific tissue expression were additionally investigated using spatial transcriptomic data in prostate tumor tissue to assess their role in tumor aggressiveness. Finally, we mapped risk proteins to drug and ongoing clinical trials targets.

Results

We identified 20 proteins genetically linked to prostate cancer risk (14 for overall [8 specific], 7 for aggressive [3 specific], and 8 for early onset disease [2 specific]), of which a majority were novel and replicated. Among these were proteins associated with aggressive disease, such as PPA2 [Odds Ratio (OR) per 1 SD increment = 2.13, 95% CI: 1.54-2.93], PYY [OR = 1.87, 95% CI: 1.43-2.44] and PRSS3 [OR = 0.80, 95% CI: 0.73-0.89], and those associated with early onset disease, including EHPB1 [OR = 2.89, 95% CI: 1.99-4.21], POGLUT3 [OR = 0.76, 95% CI: 0.67-0.86] and TPM3 [OR = 0.47, 95% CI: 0.34-0.64]. We confirm an inverse association of MSMB with prostate cancer overall [OR = 0.81, 95% CI: 0.80-0.82], and also find an inverse association with both aggressive [OR = 0.84, 95% CI: 0.82-0.86] and early onset disease [OR = 0.71, 95% CI: 0.68-0.74]. Using spatial transcriptomics data, we identified MSMB as the genome-wide top-most predictive gene to distinguish benign regions from high grade cancer regions that had five-fold lower MSMB expression. Additionally, ten proteins that were associated with prostate cancer risk mapped to existing therapeutic interventions.

Conclusion

Our findings emphasize the importance of proteomics for improving our understanding of prostate cancer etiology and of opportunities for novel therapeutic interventions. Additionally, we demonstrate the added benefit of in-depth functional analyses to triangulate the role of risk proteins in the clinical aggressiveness of prostate tumors. Using these integrated methods, we identify a subset of risk proteins associated with aggressive and early onset disease as priorities for investigation for the future prevention and treatment of prostate cancer.

O-GlcNAcylation links oncogenic signals and cancer epigenetics

Prevalent dysregulation of epigenetic modifications plays a pivotal role in cancer. Targeting epigenetic abnormality is a new strategy for cancer therapy. Understanding how conventional oncogenic factors cause epigenetic abnormality is of great basic and translational value. O-GlcNAcylation is a protein modification which affects physiology and pathophysiology. In mammals, O-GlcNAcylation is catalyzed by one single enzyme OGT and removed by one single enzyme OGA. O-GlcNAcylation is affected by the availability of the donor, UDP-GlcNAc, generated by the serial enzymatic reactions in the hexoamine biogenesis pathway (HBP). O-GlcNAcylation regulates a wide spectrum of substrates including many proteins involved in epigenetic modification. Like epigenetic modifications, abnormality of O-GlcNAcylation is also common in cancer. Studies have revealed substantial impact on HBP enzymes and OGT/OGA by oncogenic signals. In this review, we will first summarize how oncogenic signals regulate HBP enzymes, OGT and OGA in cancer. We will then integrate this knowledge with the up to date understanding how O-GlcNAcylation regulates epigenetic machinery. With this, we propose a signal axis from oncogenic signals through O-GlcNAcylation dysregulation to epigenetic abnormality in cancer. Further elucidation of this axis will not only advance our understanding of cancer biology but also provide new revenues towards cancer therapy.

Transcriptome analysis of genes related to gonad differentiation and development in Muscovy ducks

BACKGROUND

Sex-related genes play a crucial role in gonadal differentiation into testes or ovaries. However, the genetic control of gonadal differentiation in Muscovy ducks remains unknown. Therefore, the objective of our study was to screen new candidate genes associated with ovarian and testicular development.

RESULTS

In this study, 24 males before gonadal differentiation (MB), 24 females before gonadal differentiation (FB), 24 males after gonadal differentiation (MA) and 24 females after gonadal differentiation (FA) were selected from Putian Muscovy ducks, forming 4 groups. RNA-Seq revealed 101.76 Gb of clean reads and 2800 differentially expressed genes (DEGs), including 46 in MB vs FB, 609 in MA vs FA, 1027 in FA vs FB, and 1118 in MA vs MB. A total of 146 signalling pathways were enriched by KEGG analysis, among which 20, 108, 108 and 116 signalling pathways were obtained in MB vs FB, MA vs MB, MA vs FA and FA vs FB, respectively. In further GO and KEGG analyses, a total of 21 candidate genes related to gonad differentiation and development in Muscovy ducks were screened. Among these, 9 genes were involved in the differentiation and development of the testes, and 12 genes were involved in the differentiation and development of the ovaries. In addition, RNA-Seq data revealed 2744 novel genes.

CONCLUSIONS

RNA-Seq data revealed 21 genes related to gonadal differentiation and development in Muscovy ducks. We further identified 12 genes, namely, WNT5B, HTRA3, RSPO3, BMP3, HNRNPK, NIPBL, CREB3L4, DKK3, UBE2R2, UBPL3KCMF1, ANXA2, and OSR1, involved in the differentiation and development of ovaries. Moreover, 9 genes, namely, TTN, ATP5A1, DMRT1, DMRT3, AMH, MAP3K1, PIK3R1, AGT and ADAMTSL1, were related to the differentiation and development of testes. Moreover, after gonadal differentiation, DMRT3, AMH, PIK3R1, ADAMTSL1, AGT and TTN were specifically highly expressed in males. WNT5B, ANXA2 and OSR1 were specifically highly expressed in females. These results provide valuable information for studies on the sex control of Muscovy ducks and reveal novel candidate genes for the differentiation and development of testes and ovaries.

The Novel Transcription Factor CREB3L4 Contributes to the Progression of Human Breast Carcinoma

Breast carcinoma(BC)is the most common cancer type among females globally. Understanding the molecular pathways that trigger the development of BC is crucial for both prevention and treatment. As such, the role of transcription factors (TFs) in the development of BC is a focal point in this field. CREB3s play a critical role in initiating the unfolded protein response (UPR); however, the role of CREB3 family members in breast cancer development remains largely unknown. Here, we mined the ONCOMINE database for the transcriptional data of CREB3s in patients with BC. Then, the regulatory functions of a novel TF, CREB3L4, were investigated. CREB3L4 knockdown in MDA-MB-231 and MCF-7 cells suppressed proliferation and promoted apoptosis and cell cycle arrest. ChIP assays confirmed that CREB3L4 can directly bind to the PCNA promoter region, suggesting that the PCNA protein may be functionally downstream of CREB3L4. Additionally, the expression level of CREB3L4 was assessed using our cohort. CREB3L4 is upregulated in breast cancer tissues and is significantly associated with histological grade and tumour size (P = 0.001 and P < 0.001, respectively). Furthermore, PCNA expression was upregulated in breast cancer tissues and positively correlated with CREB3L4. In summary, CREB3L4 may play an important role in the progression of human BC and may serve as a therapeutic target.

Overexpression of MUC1 predicts poor prognosis in patients with breast cancer

Breast cancer is the most commonly diagnosed cancer in females; thus, there is an urgent requirement to identify precise biomarkers for the diagnosis and treatment of the disease. Mucin 1 (MUC1) is a glycoprotein that has been demonstrated to be involved in the metastasis and invasion of multiple tumor types. Bioinformatics analyses were conducted to indicate the prognostic value of MUC1 in breast cancer. Additionally, the expression level of MUC1 was assessed using Oncomine analysis. Furthermore, PrognoScan was used to analyze the prognostic value of MUC1 in breast cancer. Mutations of MUC1 were analyzed by the Catalogue of Somatic Mutations in Cancer and cBioPortal databases. In addition, University of California, Santa Cruz (UCSC) was used to examine the methylation status of MUC1. Co-expression of MUC1 mRNA was detected with the cBioPortal, UCSC and Breast Cancer Gene-Expression Miner v4.0 datasets. The results demonstrated that MCU1 is frequently overexpressed in breast cancer and is negatively associated with CpG sites. Furthermore, pooled data indicated that abnormally high expression of MUC1 indicates poor prognosis. Additionally, upregulation of MUC1 expression is associated with estrogen receptor- and progesterone receptor-positive disease, aging and increased Scarff, Bloom and Richardson grade, but is not associated with triple-negative and basal-like status. Subsequent data mining across multiple large databases demonstrated a positive association between MUC1 mRNA expression and cyclic AMP-responsive element-binding protein 3-like 4 (CREB3L4) in breast cancer tissues. The present data indicated that the overexpression of MUC1 indicates a poor prognosis in patients with breast cancer and is associated with MUC1 promoter methylation status. Additionally, MUC1 positively correlated with CREB3L4 and may serve as a potential prognostic factor and therapy target for breast cancer.

Prostate Cancer Risk and DNA Methylation Signatures in Aging Rats following Developmental BPA Exposure: A Dose-Response Analysis

BACKGROUND

Previous studies have uncovered heightened prostatic susceptibility to hormone-induced neoplasia from early-life exposure to low-dose bisphenol A (BPA). However, significant data gaps remain that are essential to address for biological relevance and necessary risk assessment.

OBJECTIVES

A complete BPA dose-response analysis of prostate lesions across multiple prostatic lobes was conducted that included internal BPA dosimetry, progression to adenocarcinoma with aging and mechanistic connections to epigenetically reprogramed genes.

METHODS

Male neonatal Sprague-Dawley rats were briefly exposed to 0.1 to 5,000 μg BPA/kg BW on postnatal days (PND) 1, 3, and 5. Individual prostate lobes plus periurethral prostatic ducts were evaluated at 7 mo or 1 y of age without or with adult testosterone plus estradiol (T+E) to promote carcinogenesis. DNA methylation of five genes was quantified by bisulfite genomic sequencing in d-200 dorsal prostates across BPA doses. Serum free-BPA and BPA-glucuronide were quantitated in sera of individual PND 3 pups collected 1 hr postexposure utilizing ultra-high-pressure tandem mass spectrometry (UHPLC-MS-MS).

RESULTS

The lowest BPA dose initiated maximal hormonal carcinogenesis in lateral prostates despite undetectable free BPA 1 hr postexposure. Further, prostatic intraepithelial neoplasia (PIN) progressed to carcinoma in rats given neonatal low-dose BPA with adult T+E but not in rats given adult T+E alone. The dorsal and ventral lobes and periurethral prostatic ducts exhibited a nonmonotonic dose response with peak PIN, proliferation and apoptotic values at 10–100 μg/kg BW. This was paralleled by nonmonotonic and dose-specific DNA hypomethylation of genes that confer carcinogenic risk, with greatest hypomethylation at the lowest BPA doses.

CONCLUSIONS

Developmental BPA exposures heighten prostate cancer susceptibility in a complex dose- and lobe-specific manner. Importantly, elevated carcinogenic risk is found at doses that yield undetectable serum free BPA. Dose-specific epigenetic modifications of selected genes provide a mechanistic framework that may connect early-life BPA to later-life predisposition to prostate carcinogenesis. https://doi.org/10.1289/EHP1050.

The role of CREB3L4 in the proliferation of prostate cancer cells

The incidence of prostate cancer (PC) is growing rapidly throughout the world, in probable association with the adoption of western style diets. Thus, understanding the molecular pathways triggering the development of PC is crucial for both its prevention and treatment. Here, we investigated the role of the metabolism-associated protein, CREB3L4, in the proliferation of PC cells. CREB3L4 was upregulated by the synthetic androgen, R1881, in LNCaP PC cells (an androgen-dependent cell line). Knockdown of CREB3L4 resulted in decreased androgen-dependent PC cell growth. LNCaP cells transfected with siCREB3L4 underwent G2/M arrest, with upregulation of the proteins cyclin B1, phospho-CDK1, p21^Waf1/Cip1, and INCA1, and downregulation of cyclin D1. Moreover, depletion of CREB3L4 resulted in significantly decreased expression of a subset of androgen-receptor (AR) target genes, including PSA, FKBP5, HPGD, KLK2, and KLK4. We also demonstrated that CREB3L4 directly interacts with the AR, and increases the binding of AR to androgen response elements (AREs). We also identified a role for the unfolded protein response (and its surrogate, IRE1α), in activating CREB3L4. Cumulatively, we postulate that CREB3L4 expression is mediated by an AR-IRE1α axis, but is also directly regulated by AR-to-ARE binding. Thus, our study demonstrates that CREB3L4 plays a key role in PC cell proliferation, which is promoted by both AR and IRE1α.

The androgen-induced protein AIbZIP facilitates proliferation of prostate cancer cells through downregulation of p21 expression

Androgen-Induced bZIP (AIbZIP) is structurally a bZIP transmembrane transcription factor belonging to the CREB/ATF family. This molecule is highly expressed in androgen-sensitive prostate cancer cells and is transcriptionally upregulated by androgen treatment. Here, we investigated molecular mechanism of androgen-dependent expression of AIbZIP and its physiological function in prostate cancer cells. Our data showed that SAM pointed domain-containing ETS transcription factor (SPDEF), which is upregulated by androgen treatment, directly activates transcription of AIbZIP. Knockdown of AIbZIP caused a significant reduction in the proliferation of androgen-sensitive prostate cancer cells with robust expression of p21. Mechanistically, we demonstrated that AIbZIP interacts with old astrocyte specifically induced substance (OASIS), which is a CREB/ATF family transcription factor, and prevents OASIS from promoting transcription of its target gene p21. These findings showed that AIbZIP induced by the androgen receptor (AR) axis plays a crucial role in the proliferation of androgen-sensitive prostate cancer cells, and could be a novel target of therapy for prostate cancer.

OASIS modulates hypoxia pathway activity to regulate bone angiogenesis

OASIS/CREB3L1, an endoplasmic reticulum (ER)-resident transcription factor, plays important roles in osteoblast differentiation. In this study, we identified new crosstalk between OASIS and the hypoxia signaling pathway, which regulates vascularization during bone development. RT-PCR and real-time PCR analyses revealed significant decreases in the expression levels of hypoxia-inducible factor-1α (HIF-1α) target genes such as vascular endothelial growth factor A (VEGFA) in OASIS-deficient (Oasis^−/−) mouse embryonic fibroblasts. In coimmunoprecipitation experiments, the N-terminal fragment of OASIS (OASIS-N; activated form of OASIS) bound to HIF-1α through the bZIP domain. Luciferase assays showed that OASIS-N promoted the transcription activities of a reporter gene via a hypoxia-response element (HRE). Furthermore, the expression levels of an angiogenic factor Vegfa was decreased in Oasis^−/− osteoblasts. Immunostaining and metatarsal angiogenesis assay showed retarded vascularization in bone tissue of Oasis^−/− mice. These results suggest that OASIS affects the expression of HIF-1α target genes through the protein interaction with HIF-1α, and that OASIS-HIF-1α complexes may play essential roles in angiogenesis during bone development.

Effects of low-fat diet and aging on metabolic profiles of Creb3l4 knockout mice

BACKGROUND/OBJECTIVES

Increased adipose tissue mass closely associates with the development of insulin resistance and type 2 diabetes mellitus. Previously, we reported that CREB3L4 expressed in adipose tissue negatively regulates adipogenesis, and Creb3l4 knockout mice fed a high-fat diet for 16 weeks showed fat cell hyperplasia, with improved glucose tolerance and insulin sensitivity. These mice did not show significant weight gain and fat mass. Because fat diet or aging is known to be associated with the development of obesity, we examined the effects of Creb3l4 gene subjected to low-fat diet (LFD) or aging process on body composition and obesity risk.

SUBJECTS/METHODS

We fed Creb3l4 knockout mice a low-fat diet for 16 weeks (LFD group) or chow diet for over 1 year (aged group) and observed various metabolic parameters in the LFD-fed and aged Creb3l4 knockout mice.

RESULTS

LFD-fed and aged Creb3l4 knockout mice showed significant weight gain and adiposity, impaired glucose tolerance and decreased insulin sensitivity, compared with wild-type mice.

CONCLUSIONS

Creb3l4 has a critical role in metabolic phenotypes and a better understanding of its function may provide improved insight into the etiology of diabetes and other metabolic disorders.

Regucalcin is an androgen-target gene in the rat prostate modulating cell-cycle and apoptotic pathways

BACKGROUND

Regucalcin (RGN) is a calcium (Ca(2+) )-binding protein underexpressed in prostate adenocarcinoma comparatively to non-neoplastic prostate or benign prostate hyperplasia cases. Moreover, RGN expression is negatively associated with the cellular differentiation of prostate adenocarcinoma, suggesting that loss of RGN may be associated with tumor onset and progression. However, the RGN actions over the control of prostate cell growth have not been investigated.

METHODS

Androgens are implicated in the promotion of prostate cell proliferation, thus we studied the in vivo effect of androgens on RGN expression in rat prostate. The role of RGN modulating cell proliferation and apoptotic pathways in rat prostate was investigated using transgenic animals (Tg-RGN) overexpressing the protein.

RESULTS

In vivo stimulation with 5α-dihydrotestosterone (DHT) down-regulated RGN expression in rat prostate. Cell proliferation index and prostate weight were reduced in Tg-RGN, which was concomitant with altered expression of cell-cycle regulators. Tg-RGN presented diminished expression of the oncogene H-ras and increased expression of cell-cycle inhibitor p21. Levels of anti-apoptotic Bcl-2, as well as the Bcl-2/Bax protein ratio were increased in prostates overexpressing RGN. Both caspase-3 expression and enzyme activity were decreased in the prostates of Tg-RGN.

CONCLUSIONS

Overexpression of RGN resulted in inhibition of cell proliferation and apoptotic pathways, which demonstrated its role maintaining prostate growth balance. Thus, deregulation of RGN expression may be an important event favoring the development of prostate cancer. Moreover, the DHT effect down-regulating RGN expression in rat prostate highlighted for the importance of this protein in prostatic physiology.

Identification and characterization of five intramembrane metalloproteases in Anabaena variabilis

Regulated intramembrane proteolysis (RIP) involves cleavage of a transmembrane segment of a protein, releasing the active form of a membrane-anchored transcription factor (MTF) or a membrane-tethered signaling protein in response to an extracellular or intracellular signal. RIP is conserved from bacteria to humans and governs many important signaling pathways in both prokaryotes and eukaryotes. Proteases that carry out these cleavages are named intramembrane cleaving proteases (I-CLips). To date, little is known about I-CLips in cyanobacteria. In this study, five putative site-2 type I-Clips (Ava_1070, Ava_1730, Ava_1797, Ava_3438, and Ava_4785) were identified through a genome-wide survey in Anabaena variabilis. Biochemical analysis demonstrated that these five putative A. variabilis site-2 proteases (S2Ps(Av)) have authentic protease activities toward an artificial substrate pro-σ(K), a Bacillus subtilis MTF, in our reconstituted Escherichia coli system. The enzymatic activities of processing pro-σ(K) differ among these five S2Ps(Av). Substitution of glutamic acid (E) by glutamine (Q) in the conserved HEXXH zinc-coordinated motif caused the loss of protease activities in these five S2Ps(Av), suggesting that they belonged to the metalloprotease family. Further mapping of the cleaved peptides of pro-σ(K) by Ava_4785 and Ava_1797 revealed that Ava_4785 and Ava_1797 recognized the same cleavage site in pro-σ(K) as SpoIVFB, a cognate S2P of pro-σ(K) from B. subtilis. Taking these results together, we report here for the first time the identification of five metallo-intramembrane cleaving proteases in Anabaena variabilis. The experimental system described herein should be applicable to studies of other RIP events and amenable to developing in vitro assays for I-CLips.

CREB3 subfamily transcription factors are not created equal: Recent insights from global analyses and animal models

The CREB3 subfamily of membrane-bound bZIP transcription factors has five members in mammals known as CREB3 and CREB3L1-L4. One current model suggests that CREB3 subfamily transcription factors are similar to ATF6 in regulated intramembrane proteolysis and transcriptional activation. Particularly, they were all thought to be proteolytically activated in response to endoplasmic reticulum (ER) stress to stimulate genes that are involved in unfolded protein response (UPR). Although the physiological inducers of their proteolytic activation remain to be identified, recent findings from microarray analyses, RNAi screens and gene knockouts not only demonstrated their critical roles in regulating development, metabolism, secretion, survival and tumorigenesis, but also revealed cell type-specific patterns in the activation of their target genes. Members of the CREB3 subfamily show differential activity despite their structural similarity. The spectrum of their biological function expands beyond ER stress and UPR. Further analyses are required to elucidate the mechanism of their proteolytic activation and the molecular basis of their target recognition.

Androgens modulate autophagy and cell death via regulation of the endoplasmic reticulum chaperone glucose-regulated protein 78/BiP in prostate cancer cells

Pro-survival signalling mediated by the androgen receptor (AR) is implicated as a key contributor to prostate carcinogenesis. As prostate tumours are characterized by nutrient-poor, hypoxic and acidified microenvironments, one mechanism whereby AR signalling may contribute to survival is by promoting adaptation to cellular stress. Here we have identified a novel role for AR in the inhibition of autophagy induced by serum withdrawal. This blockade is attributed to AR-mediated upregulation of the endoplasmic reticulum (ER) chaperone glucose-regulated protein 78/BiP (Grp78/BiP), and occurs independently of ER stress response pathway activation. Interestingly, AR activation did not affect serum starvation-induced mammalian target of rapamycin inhibition, illustrating that the adaptive role for androgens lies not in the ability to modulate nutrient sensing, but in the promotion of ER stability. Finally, we show that the adaptive advantage conferred by AR-mediated Grp78/BiP upregulation is temporary, as upon chronic serum starvation, AR activation delayed but did not suppress the onset of autophagy and cell death. This study reveals a novel mechanism whereby maintained AR signalling promotes temporary adaptation to cellular stress and in turn may contribute to the evasion of prostate tumour cell death.

Requirement of the epithelium-specific Ets transcription factor Spdef for mucous gland cell function in the gastric antrum

Mucus-secreting cells of the stomach epithelium provide a protective barrier against damage that might result from bacterial colonization or other stimuli. Impaired barrier function contributes to chronic inflammation and cancer. Knock-out mice for the epithelium-specific transcription factor Spdef (also called Pdef) have defects in terminal differentiation of intestinal and bronchial secretory cells. We sought to determine the physiologic function of Spdef in the stomach, another site of significant levels of Spdef expression. We used in situ hybridization and immunohistochemistry to localize Spdef-expressing cells in the mouse stomach; targeted gene disruption to generate mice lacking Spdef; and histologic, immunologic, and transcriptional profiling approaches to determine the requirements of Spdef in stomach epithelial homeostasis. In wild-type mice, Spdef RNA and protein are expressed predominantly in mucous gland cells of the antrum and in mucous neck cells of the glandular corpus. Within 1.5 years, nearly half of homozygous mutant mice developed profound mucosal hyperplasia of the gastric antrum. Submucosal infiltration of inflammatory cells preceded antral hyperplasia by several weeks. The absence of Spdef impaired terminal maturation of antral mucous gland cells, as reflected in reduced expression of Muc6 and Tff2 and reduced numbers of secretory granules. Antral gene expression abnormalities overlapped significantly with those in Spdef(-/-) colon, including genes implicated in secretory granule traffic and functions. Spdef is required for terminal maturation of antral mucous gland cells to protect animals from gastric inflammation and resulting hyperplasia. These requirements parallel Spdef functions in secretory intestinal cells and suggest a common molecular mechanism for maturation of gastrointestinal secretory lineages.

Gene expression during successful implantation in a natural cycle

OBJECTIVE

To determine the human endometrial transcriptome during embryonic implantation.

DESIGN

Case report.

SETTING

Tertiary fertility center.

PATIENT(S)

A 24-year-old woman who inadvertently became pregnant during an endometrial biopsy procedure.

INTERVENTION(S)

An endometrial biopsy was performed with a Pipelle device during the midluteal phase (days 19-21) of the cycle; blood samples for hormonal assessments were collected and a transvaginal ultrasound was performed.

MAIN OUTCOME MEASURE(S)

Gene expression analysis of the endometrium during the window of implantation (during the implantation of an embryo) in a natural cycle. Localization of selected genes in endometrial tissue with immunohistochemistry.

RESULT(S)

A total of 394 probe sets were differentially expressed in the pregnant sample when compared with the midsecretory phase nonpregnant endometrial samples. Different gene networks were involved, and selected genes from these signaling pathways were confirmed at the protein level.

CONCLUSION(S)

Endometrial gene expression of a pregnant patient in a natural cycle is significantly different from nonpregnant patients during the midsecretory phase.