TRIB3 promotes the progression of renal cell carcinoma by upregulating the lipid droplet-associated protein PLIN2.

Abnormal lipid metabolism and lipid accumulation are characteristic hallmarks of renal cell carcinoma (RCC). While there is prior evidence closely linking such lipid accumulation within RCC cells and consequent tumorigenesis, the mechanisms underlying this process remain incompletely understood. In this study, a series of bioinformatics analyses were initially performed by screening RCC databases and gene sets, ultimately leading to the identification of TRIB3 as an oncogene that functions as a central regulator of lipid metabolism. TRIB3 overexpression was observed in both RCC patient tumor tissues and cell lines, and this upregulation was correlated with a worse RCC patient prognosis. When TRIB3 was knocked down, this resulted in a reduction in lipid accumulation and the consequent induction of endoplasmic reticulum (ER) stress-related apoptotic cell death. At the molecular level, interactions between TRIB3 and PLIN2 were found to abrogate TEB4-mediated PLIN2 ubiquitination and consequent degradation, thus maintaining higher PLIN2 expression levels. This simultaneously helps facilitate the accumulation of lipids while preserving ER homeostasis, thus driving accelerated RCC tumor progression. This TRIB3-PLIN2 axis thus represents a promising new target for efforts to treat RCC.

Association of cigarette smoking habits with the risk of prostate cancer: a systematic review and meta-analysis.

BACKGROUND: Association of cigarette smoking habits with the risk of prostate cancer is still a matter of debate. This systematic review and meta-analysis aimed to assess the association between cigarette smoking and prostate cancer risk. METHODS: We conducted a systematic search on PubMed, Embase, Cochrane Library, and Web of Science without language or time restrictions on June 11, 2022. Literature search and study screening were performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement. Prospective cohort studies that assessed the association between cigarette smoking habits and the risk of prostate cancer were included. Quality assessment was conducted using the Newcastle-Ottawa Scale. We used random-effects models to obtain pooled estimates and the corresponding 95% confidence intervals. RESULTS: A total of 7296 publications were screened, of which 44 cohort studies were identified for qualitative analysis; 39 articles comprising 3 296 398 participants and 130 924 cases were selected for further meta-analysis. Current smoking had a significantly reduced risk of prostate cancer (RR, 0.74; 95% CI, 0.68-0.80; P < 0.001), especially in studies completed in the prostate-specific antigen screening era. Compared to former smokers, current smokers had a significant lower risk of PCa (RR, 0.70; 95% CI, 0.65-0.75; P < 0.001). Ever smoking showed no association with prostate cancer risk in overall analyses (RR, 0.96; 95% CI, 0.93-1.00; P = 0.074), but an increased risk of prostate cancer in the pre-prostate-specific antigen screening era (RR, 1.05; 95% CI, 1.00-1.10; P = 0.046) and a lower risk of prostate cancer in the prostate-specific antigen screening era (RR, 0.95; 95% CI, 0.91-0.99; P = 0.011) were observed. Former smoking did not show any association with the risk of prostate cancer. CONCLUSIONS: The findings suggest that the lower risk of prostate cancer in smokers can probably be attributed to their poor adherence to cancer screening and the occurrence of deadly smoking-related diseases, and we should take measures to help smokers to be more compliant with early cancer screening and to quit smoking. TRIAL REGISTRATION: This study was registered on PROSPERO (CRD42022326464).

Efficacy and safety of Androgen Deprivation Therapy (ADT) combined with modified docetaxel chemotherapy versus ADT combined with standard docetaxel chemotherapy in patients with metastatic castration-resistant prostate cancer: study protocol for a multicentre prospective randomized controlled trial.

BACKGROUND: Androgen deprivation therapy (ADT) combined with docetaxel chemotherapy is the standard treatment for metastatic castration-resistant prostate cancer (mCRPC) patients. However, mCRPC patients are mainly frail elderly men, constantly accompanied by comorbidities and showing poor tolerance to standard docetaxel chemotherapy. Some exploratory studies administering modified chemotherapy regimens have reported noninferior oncologic outcomes with fewer adverse events, yet most are retrospective or small studies, and prospective randomized controlled trials have rarely been conducted. Therefore, we designed this modified docetaxel chemotherapy regimen in patients with mCRPC, aiming to evaluate its efficacy and safety compared with the standard docetaxel chemotherapy regimen. METHODS: This is an open-label, multi-institutional, prospective, randomized non-inferiority trial. A total of 128 patients with mCRPC will be randomized to receive ADT combined with modified docetaxel chemotherapy (experimental group, n=64) or ADT combined with standard docetaxel chemotherapy (control group, n=64). Patients in the experimental group will receive a modified regimen with docetaxel 40 mg/m2 on the 1st day and 35 mg/m2 on the 8th day, repeated every 21 days. The primary endpoint is progression-free survival at 2 years. Secondary endpoints include overall survival, prostate-specific antigen response rate, pain response rate, toxicity and quality of life. DISCUSSION: The expected benefit for the patient in the experimental arm is noninferior efficacy with decreased toxicity and improved quality of life compared with that in the control arm. To the best of our knowledge, this will be the first multicentre prospective randomized study to assess the efficacy and safety of modified docetaxel chemotherapy in patients with mCRPC in China. The results of this trial may provide benefit to mCRPC patients, especially those with poor performance. TRIAL REGISTRATION: chictr.org.cn Identifier: ChiCTR2100046636 (May 24, 2021). Ongoing study.

Which Way to Choose for the Treatment of Metastatic Prostate Cancer: A Case Report and Literature Review.

BACKGROUND: Prostate cancer (PCa) is the second most common cancer among males in the world and the majority of patients will eventually progress to the metastatic phase. How to choose an effective way for the treatment of metastatic PCa, especially in the later stage of the disease is still confusing. Herein we reported the case of a patient diagnosed with metastatic PCa and conducted a literature review on this issue. CASE PRESENTATION: A 57-year-old man with metastatic PCa had been managed by Dr. J.P. since April 2012 when the patient was admitted to the Third Affiliated Hospital of Sun Yat-sen University by aggravating frequent urination and dysuria. The prostate-specific antigen (PSA) concentration was 140 ng/ml, and the diagnosis of PCa was confirmed by prostate biopsy, with Gleason score 4 + 5 = 9. Chest CT and bone scan indicated multiple metastases in the lungs and bones. Triptorelin, bicalutamide, zoledronic acid, and docetaxel were then administered, six cycles later, the metastatic tumors in the lungs disappeared and those in the bones lessened significantly, along with a remarkable reduction in PSA level (< 2 ng/ml). Intermittent androgen deprivation was subsequently conducted until August 2018, when the serum PSA level was found to be 250 ng/ml, again docetaxel 75 mg/m2 was administered immediately but the patient was intolerant this time. Instead, abiraterone was administered until March 2019 because of intolerable gastrointestinal side-effects and increasing PSA level. In October 2019, the patient came to our center, a modified approach of docetaxel (day 1 40 mg/m2 + day 8 35 mg/m2) was administered. Luckily, the PSA level decreased rapidly, the bone pain was greatly relieved, and no obvious side effects occurred. However, four cycles later, docetaxel failed to work anymore, the metastatic tumor in the liver progressed. We proposed several regimens as alternatives, but they were soon denied due to the high prices or unavailability or uncertain effect of the drugs. In addition, the patient's condition deteriorated speedily and can no longer bear any aggressive treatment. Finally, the patient died of multiple organ failure in August 2020. CONCLUSION: The experiences of this case provide valuable evidence and reference for the treatment choices of metastatic PCa, in some circumstances modified and advanced regimens may produce unexpected effects.

[Corrigendum] The specific killing effect of matrine on castration­resistant prostate cancer cells by targeting the Akt/FoxO3a signaling pathway.

Subsequently to the publication of the article, the authors have realized that some errors were contained therein that went uncorrected before the paper was sent to press. First, Fig. 4 contained a pair of data panels that had been misplaced: The LY294002, PC­3 data panel in Fig. 4A showed the same data as the RWPE­1, control panel in Fig. 4B, and the LY294002, RWPE­1 data panel showed the same data as the matrine, control panel in Fig. 4B. These errors arose inadvertently during the process of re­organizing the layout of the figure; a corrected version of Fig. 4, showing the correct data panels for the LY294002, PC­3 and LY294002, RWPE­1 experiments in Fig. 4A and B respectively, is shown on the next page. Also note that the data shown in Fig. 4C and E have been re­calculated on the basis of the correction of the data in this Figure, and the revised histograms are also shown in these Figure parts. In view of these corrections, in the "Matrine induces cell apoptosis by increasing Bim and Bax and decreasing Bcl­2 protein levels in prostate cancer cell lines" subsection of the Results section towards the bottom of p. 2822, in the penultimate sentence, the text "...LY294002 resulted in 25.88% cell apoptosis in the PC­3 cells and 18.88% in the RWPE1 cells, compared to 3.11 and 6.89%, respectively, with LY294002 treatment only (Fig. 4A­D)." should be corrected to: "...LY294002 resulted in 25.88% cell apoptosis in the PC­3 cells and 18.88% in the RWPE1 cells, compared to 10.94% and 6.89%, respectively, with LY294002 treatment only (Fig. 4A­D)." (the changed datum is shown in bold). Note that the corrected data shown in Fig. 4, and the revision made to the Results section, do not affect the overall conclusions reported in the paper. The authors thank the Editor of Oncology Reports for allowing them the opportunity to present this Corrigendum, and apologize and to the readership for any inconvenience caused. [the original article was published in Oncology Reports 37: 2819-2828, 2017; DOI: 10.3892/or.2017.5510].

Polo-like kinase 3 is associated with poor prognosis and regulates proliferation and metastasis in prostate cancer.

BACKGROUND: Biological mechanism of prostate cancer (PCa) recurrence and progress is complex but many of the key elements are not fully understood. Polo-like kinases (Plks) represent a family of highly conserved serine-threonine kinases that play essential roles in cell cycle progression. Plk3 plays contradictory roles in different cancers. However, the roles of Plk3 in PCa remain largely unexplored. METHODS: Kaplan-Meier analysis and Cox regression analysis were performed to evaluate the relationship between Plk3 and prognosis of patients with PCa. Gene set enrichment analysis (GSEA) was conducted to evaluate proliferation and metastasis gene sets using The Cancer Genome Atlas Dataset. MTS assay, clone formation assay, cell migration, and wound healing assay were carried out to investigate biological functions of Plk3. RESULTS: We found that high Plk3 expression was closely correlated with poor prognosis. GSEA revealed that Plk3 was involved in proliferation and metastasis. Loss-of-function assays demonstrated that Plk3 promoted proliferation and metastasis in PCa cells in vitro. CONCLUSION: We discovered that Plk3 plays a critical role in PCa, indicating that it may be a potential prognostic marker and help predict the progression, especially recurrence of PCa.

High levels of glioma tumor suppressor candidate region gene 1 predicts a poor prognosis for prostate cancer.

Glioma tumor suppressor candidate region gene 1 (GLTSCR1) is associated with the progression of oligodendroglioma. However, there has been little study of GLTSCR1 in prostate cancer. In the present study, the association between the expression of GLTSCR1, and the progression and prognosis of tumors in patients with prostate cancer was assessed. An immunohistochemical analysis was performed using a human tissue microarray for GLTSCR1 at the protein expression level and the immunostaining results were evaluated against clinical variables of patients with prostate cancer. Subsequently, The Cancer Genome Atlas (TCGA) was used to validate the analysis results at the mRNA level and to study the prognostic value of GLTSCR1 in prostate cancer. Immunohistochemistry and TCGA data analysis revealed that GLTSCR1 expression in the prostate cancer tissues was significantly higher than that in the benign prostate tissues (immunoreactivity score, P=0.015; mRNA levels: cancer, 447.7±6.45 vs. benign, 343.5±4.21; P<0.001). Additionally, the increased GLTSCR1 protein expression was associated with certain clinical variables in the prostate cancer tissues, including advanced clinical stage (P<0.001), enhanced tumor invasion (P=0.003), lymph node metastasis (P=0.003) and distant metastasis (P=0.001). TCGA data revealed similar results, demonstrating that the upregulation of GLTSCR1 mRNA expression was associated with the Gleason score (P<0.001), enhanced tumor invasion (P=0.011), lymph node metastasis (P=0.001) and distant metastasis (P=0.002). Furthermore, Kaplan-Meier analysis suggested that among all patients, high GLTSCR1 expression indicated a decreased overall survival (P=0.028) and biochemical recurrence (BCR)-free survival (P=0.004), compared with patients with low GLTSCR1 expression. Finally, multivariate analysis revealed that the expression of GLTSCR1 was an independent predictor of poor BCR-free survival (P=0.049). The present study suggested that the increased expression of GLTSCR1 was associated with the progression of prostate cancer. Furthermore, GLTSCR1 may be a novel biomarker that is able to predict the clinical outcome in prostate cancer patients.

Decreased expression of serine protease inhibitor family G1 (SERPING1) in prostate cancer can help distinguish high-risk prostate cancer and predicts malignant progression.

PURPOSE: The aim of this study was to investigate the associations of serine proteinase inhibitor family G1 (SERPING1) down-regulation with poor prognosis in patients with prostate cancer (PCa). Furthermore, we aim to find more novel and effective PCa molecular markers to provide an early screening of PCa, distinguish patients with aggressive PCa, predict the prognosis, or reduce the economic burden of PCa. METHODS: SERPING1 protein expression in both human PCa and normal prostate tissues was detected by immunohistochemical staining, which intensity was analyzed in association with clinical pathological parameters such Gleason score, pathological grade, clinical stage, tumor stage, lymph node metastasis, and distant metastasis. Moreover, we used The Cancer Genome Atlas (TCGA) Database, Taylor Database, and Oncomine dataset to validate our immunohistochemical results and investigated the value of SERPING1 in PCa at mRNA level. Kaplan-Meier analysis and Cox regression analysis were performed to evaluate the relationship between SERPING1 and prognosis of patients with PCa. RESULTS: The outcome showed that SERPING1 was expressed mainly in cytoplasm of grand cells of prostate tissue and was significantly expressed less in PCa (P<0.001). Furthermore, in the tissue microarray of our samples, decreasing expression of SERPING1 was correlated with the higher Gleason score (P = 0.004), the higher pathological grade (P = 0.01) and the advanced tumor stage (P = 0.005) at protein level. In TCGA dataset and Taylor Dataset, low-expressed SERPING1 was correlated with the younger patient (P = 0.02 in TCGA, P = 0.044 in Taylor) and the higher Gleason score (P = 0.019 in TCGA, P<0.001 in Taylor) at mRNA level. Kaplan-Meier analysis revealed that the lower mRNA of SERPING1 predicted lower overall survivals (P = 0.027 in TCGA), lower disease-free survival (P = 0.029) and lower biochemical recurrence-free survival (P = 0.011 in Taylor). Data from Oncomine database shown that SERPING1 low expression implying higher malignancy of prostate lesions. Using multivariate analysis, we also found that SERPING1 expression was independent prognostic marker of poor disease-free survival and biochemical recurrence-free survival. CONCLUSION: SERPING1 may play an important role in PCa and can be serve as a novel marker in diagnosis and prognostic prediction in PCa. In addition, levels of SERPING1 can help identify low-risk prostate to provide reference for patients with PCa to accept active surveillance and reduce overtreatment.

High levels of DEPDC1B predict shorter biochemical recurrence-free survival of patients with prostate cancer.

DEP domain-containing protein 1B (DEPDC1B) has been reported to serve important functions in breast cancer and non-small cell lung cancer. However, its involvement in the development of prostate cancer (PCa) remains unclear. Therefore, the present study aimed to investigate the expression and clinical significance of DEPDC1B in tumor tissues from patients diagnosed with PCa. A total of 80 prostate tissue samples were collected following prostatectomy to generate a tissue microarray for immunohistochemical analysis of DEPDC1B protein expression. High throughput sequencing of mRNAs from 179 prostate tissue samples, either from patients with PCa or from healthy controls, was included in the Taylor dataset. The expression levels of DEPDC1B in tumor tissues from patients with PCa were revealed to be significantly increased compared with those in normal prostate tissues (P=0.039). Increased expression of DEPDC1B was significantly associated with advanced clinical stage (P=0.006), advanced T stage (P=0.012) and lymph node metastasis (P=0.004). Kaplan-Meier analysis demonstrated that patients with high levels of DEPDC1B mRNA had significantly shorter biochemical recurrence (BCR)-free survival times. Multivariate analysis using Cox proportional hazards model revealed that levels of DEPDC1B mRNA were significant independent predictors of BCR-free survival time of patients with PCa. Therefore, the expression of DEPDC1B may be used as an independent predictor of biochemical recurrence-free survival time of patients with PCa.

The specific killing effect of matrine on castration-resistant prostate cancer cells by targeting the Akt/FoxO3a signaling pathway.

Matrine, a Sophora alkaloid, exhibits antiproliferative and anti-carcinogenic activities through several mechanisms. In a previous study, we found that matrine could effectively inhibit the proliferation of castration-resistant prostate cancer (CRPC). In the present study, the effect of matrine and LY294002 on the expression of the Akt/FoxO3a signaling pathway was examined by western blot analyses and RT-PCR. We discovered that matrine significantly inhibited the proliferation of both prostate cancer cell line PC-3 and prostate epithelial cell line RWPE1, induced apoptosis and induced cell cycle arrest. In addition, LY294002 was found to enhance the effect of matrine. Furthermore, the effects of matrine on the inhibition of proliferation and the induction of cell cycle arrest and cell apoptosis were more effective on PC-3 than on RWPE1 cells. Compared to RWPE1 cells, matrine exerted a more powerful influence on PC-3 cells in increasing the expression of the relevant protein. Our data suggested that FoxO3a-Bim and FoxO3a-P27 may mediate matrine-inhibited proliferation of CRPC cells by activating cell apoptosis and inducing cell cycle arrest. Matrine exhibited high selectivity in killing CRPC cells. Our findings demonstrated that matrine could be used in a potential therapeutic role in the management of CRPC in humans.

Matrine suppresses invasion of castration-resistant prostate cancer cells by downregulating MMP-2/9 via NF-κB signaling pathway.

Matrine is an alkaloid from Sophora flavescens that exhibits multiple protective effects on cancers. However, the molecular mechanisms of anti-metastatic effects of matrine on castration-resistant prostate cancer (CRPC) remain unknown. This study investigated the anti-metastatic effects of matrine on CRPC to identify the underlying mechanisms. The effects of matrine on the cell viability of DU145 and PC-3 cells were measured using MTS assay. The impact of matrine on expression levels of matrix metalloproteinase (MMP)-9, MMP-2, nuclear factor-κB (NF-κB) subunit p65 and phosphorylated p65 in cells untreated or treated with matrine were analyzed by western blotting. The inhibitory effects of matrine on cell migration and invasion were examined by Transwell assay. The impact of matrine on tumorigenesis in male Balb/c nude mice inoculated subcutaneously with cells were investigated in vivo. We found that matrine inhibited the growth of DU145 and PC3 cells time- and dose-dependently both in vitro and in vivo. Migration and invasion capabilities of cells were also suppressed by matrine. At the same time, matrine markedly reduced the expression levels of MMP-9, MMP-2 and p-p65 in both cell lines. Further experiments revealed that matrine exhibited inhibitory effects of migration and invasion of CRPC by downregulating MMP-2/9 through NF-κB pathway. Matrine inhibits invasion of CRPC by reducing levels of MMP-9 and MMP-2 through NF-κB pathway. Therefore, it may be a potential anti-metastatic therapeutic agent for CRPC.

Elevated levels of epithelial cell transforming sequence 2 predicts poor prognosis for prostate cancer.

Epithelial cell transforming sequence 2 (Ect2) was originally reported as an oncogene that is involved in several types of human cancers. However, little is known about its expression and function in prostate cancer. Immunohistochemical staining for Ect2 was performed on a human tissue microarray. The staining intensity was analyzed in association with clinical pathological parameters such as Gleason score, pathological grade, clinical stage, tumor invasion, lymph node and distant metastasis. Furthermore, we repeated such analysis and investigated the prognostic value of Ect2 using the TCGA (The Cancer Genome Atlas) Dataset. Our immunohistochemical results showed that the expression levels of Ect2 protein were enhanced in human prostate cancer tissues. There existed positive correlations between the expression levels of Ect2 and several clinicopathological parameters, including advanced clinical stage, enhanced tumor invasion and lymph node metastasis. Similarly, we found that the expression levels of Ect2 were positively related to Gleason score, tumor invasion, lymph node metastasis and high distant metastasis in the TCGA Dataset. Kaplan-Meier analysis revealed that lower levels of Ect2 mRNA predicted higher overall survivals and biochemical recurrence (BCR)-free survivals in all patients or non-metastatic patients. Multivariate analysis by Cox regression showed that the expression of Ect2 could be an independent prognostic marker of poor BCR-free survivals. Therefore, levels of Ect2 may serve as a novel marker for the diagnosis or prognosis of prostate cancer.

Identification of differentially methylated regions (DMRs) of neuronatin in mice.

BACKGROUND: Neuronatin (NNAT) is a paternal-inherited imprinted gene, first discovered in the rat neonatal brain, where it plays vital roles for neuronal growth, brain development, and metabolic regulation. The maternal imprint of NNAT has been identified in mice; however, the differentially methylated regions (DMRs) involved in the monoallelic expression of NNAT have not yet been investigated. RESULTS: In this study, we confirmed expression of two isoforms of the NNAT (α and ß) in the mice brain via quantitative RT-PCR. Additionally, the methylation profile of the CpG island located in the NNAT gene locus was determined in the mice liver, brain, sperm, and the MII oocyte via bisulfite sequencing PCR. CONCLUSION: In summary, we provide the first evidence for tissue- and gamete-specific methylation patterns of CpG3 that are located on exon 1, to be putative DMR of NNAT in mice.

Conservation of imprinting of Neuronatin (Nnat) in rabbits.

Although the expression and epigenetic status of imprinted genes have been extensively studied in a number of species, less is known about the genomic imprinting in rabbits. Neuronatin (Nnat) plays significant roles in the brain development and metabolic regulation and has been identified to be imprinted and paternally expressed in humans, mice and pigs; however, it has not yet been investigated in rabbits. In this study, we confirmed the expression of two isoforms of the rabbit Nnat (Nnat-a and Nnat-ß) identified in Genbank and Ensembl by quantitative real-time PCR. In addition, we also determined the methylation profile of the CpG island in the promoter region of the rabbit Nnat using bisulfite sequencing PCR and combined bisulfite restriction analysis. Here, we provide the first evidence that Nnat has two transcripts in rabbit. Additionally, the CpG island located in the promoter region shows oocyte-specific methylation and may be the differentially methylated region of Nnat in rabbits.

SHARPIN overexpression induces tumorigenesis in human prostate cancer LNCaP, DU145 and PC-3 cells via NF-κB/ERK/Akt signaling pathway.

SHARPIN emerges higher expression in prostate cancerous tissues than in benign prostate hyperplasia by means of immunohistochemistry in our previous study. In this work, we performed the gain of function assay and find that overexpression of SHARPIN in LNCaP, DU145 and PC-3 cells promoted cell proliferation, invasiveness and reduced apoptosis. Furthermore, SHARPIN overexpression displayed elevated Bcl-2 and Survivin expression and reduced levels of Bax, cleaved caspase-3. Meanwhile, entropic expression of SHARPIN increased the levels of phosphorylated p65, IkBα, ERK and Akt, were selectively increased in these cells. Collectively, our study unraveled the ability of SHARPIN overexpression to induce tumorigenesis of prostate cancer cells through the NF-kB/ERK/Akt pathway and transformation of apoptosis-associated proteins.

DNA methylation-mediated silencing of neuronatin (NNAT) in pig parthenogenetic fetuses.

It is generally believed that aberrant expression of imprinted genes participates in growth retardation of mammalian parthenogenesis. Neuronatin (NNAT), a paternally expressed gene, plays important roles in neuronal growth and metabolic regulation. Here we have compared the gene expression and promoter methylation pattern of NNAT between pig normally fertilized (Con) and parthenogenetic (PA) embryos. The results showed loss of NNAT expression (p<0.001) and hypermethylation of NNAT promoter in PA samples. Additionally, partial methylation was observed in Con fetuses, while almost full methylation and unmethylation of NNAT promoter were apparent in Metaphase II (MII) oocytes and mature sperms, respectively, which identified the CpG promoter region as a putative differentially methylated region (DMR) of NNAT. The data demonstrate that promoter hypermethylation is associated with the silencing of NNAT in pig PA fetuses, which may be related to developmental failure of pig parthenogenesis at early stages.

Disruption of imprinted gene expression and DNA methylation status in porcine parthenogenetic fetuses and placentas.

Parthenogenetically activated oocytes cannot develop to term in mammals due to the lack of paternal gene expression and failed X chromosome inactivation (XCI). To further characterize porcine parthenogenesis, the expression of 18 imprinted genes was compared between parthenogenetic (PA) and normally fertilized embryos (Con) using quantitative real-time PCR (qRT-PCR). The results revealed that maternally expressed genes were over-expressed, whereas paternally expressed genes were significantly reduced in PA fetuses and placentas. The results of bisulfite sequencing PCR (BSP) demonstrated that PRE-1 and Satellite were hypermethylated in both Con and PA fetuses and placentas, while XIST DMRs were hypomethylated only in PA samples. Taken together, these results suggest that the aberrant methylation profile of XIST DMRs and abnormal imprinted gene expression may be responsible for developmental failure and impaired growth in porcine parthenogenesis.

Elevated expression of vascular endothelial growth factor (VEGF) 120 in parthenogenetic porcine placentas.

Most mammalian parthenogenetic embryos are unable to develop to term due to placental defects, potentially caused by decreased vasculogenesis and angiogenesis of the parthenogenetic placenta. Here we have compared the expression status of vascular endothelial growth factor (VEGF) and angiopoietin family members between normally developing and parthenogenetic porcine placentas. The result showed significantly reduced expression of these genes but elevated expression of VEGF 120 in the parthenogenetic porcine placenta (p < 0.05). We postulate that the abnormal expression levels of VEGF and angiopoietin family members and, especially, the elevated expression of VEGF 120 observed in parthenogenetic porcine placentas are related to the early miscarriage of parthenogenetic embryos in pigs.

Aberrant expression of Igf2/H19 in porcine parthenogenetic fetuses and placentas.

The aberrant expression of imprinted genes induces parthenogenetic fetal and placental dysplasia, thus leading to failures in embryonic development. Igf2 and H19 are co-expressed in endoderm and mesoderm-derived tissues and play an important role in normal embryo and extraembryonic development. In this study, the expression and methylation of Igf2/H19 in porcine parthenogenetic fetuses and placentas which had grown 28 days was examined first time to further characterize mammalian parthenogenesis. Weight and morphological comparisons were conducted between parthenogenetic embryos on Day 28 and normal fertilized embryos (control). The results indicated that parthenogenetic fetuses and placentas had smaller weights and volumes than those of the control. In addition, quantitative RT-PCR (qRT-PCR) analysis was performed to determine Igf2/H19 expression levels, showing that the expression of H19 was up-regulated, while Igf2 expression was almost undetectable in both parthenogenetic fetuses and placentas. As a potential mechanism underlying this disrupted expression, the methylation of Igf2/H19 DMR3 was detected using bisulfite sequencing PCR analysis, which revealed the significant hypomethylation of DMR3 in parthenogenetic fetuses and placentas. These results suggest that disruption of Igf2/H19 expression in parthenogenetic fetuses and placentas contributes to implantation failure and/or abortion in swine parthenogenesis, which might be associated with differential methylation patterns in the imprinting control region of imprinted genes.