EIF2AK4 Mutations in Patients Diagnosed With Pulmonary Arterial Hypertension.

BACKGROUND: Differentiating pulmonary venoocclusive disease (PVOD) and pulmonary capillary hemangiomatosis (PCH) from idiopathic pulmonary arterial hypertension (IPAH) or heritable pulmonary arterial hypertension (HPAH) is important clinically. Mutations in eukaryotic translation initiation factor 2 alpha kinase 4 (EIF2AK4) cause heritable PVOD and PCH, whereas mutations in other genes cause HPAH. The aim of this study was to describe the frequency of pathogenic EIF2AK4 mutations in patients diagnosed clinically with IPAH or HPAH. METHODS: Sanger sequencing and deletion/duplication analysis were performed to detect mutations in the bone morphogenetic protein receptor type II (BMPR2) gene in 81 patients diagnosed at 30 North American medical centers with IPAH (n = 72) or HPAH (n = 9). BMPR2 mutation-negative patients (n = 67) were sequenced for mutations in four other genes (ACVRL1, ENG, CAV1, and KCNK3) known to cause HPAH. Patients negative for mutations in all known PAH genes (n = 66) were then sequenced for mutations in EIF2AK4. We assessed the pathogenicity of EIF2AK4 mutations and reviewed clinical characteristics of patients with pathogenic EIF2AK4 mutations. RESULTS: Pathogenic BMPR2 mutations were identified in 8 of 72 (11.1%) patients with IPAH and 6 of 9 (66.7%) patients with HPAH. A novel homozygous EIF2AK4 mutation (c.257+4A>C) was identified in 1 of 9 (11.1%) patients diagnosed with HPAH. The novel EIF2AK4 mutation (c.257+4A>C) was homozygous in two sisters with severe pulmonary hypertension. None of the 72 patients with IPAH had biallelic EIF2AK4 mutations. CONCLUSIONS: Pathogenic biallelic EIF2AK4 mutations are rarely identified in patients diagnosed with HPAH. Identification of pathogenic biallelic EIF2AK4 mutations can aid clinicians in differentiating HPAH from heritable PVOD or PCH.

BMPR2 mutations and survival in pulmonary arterial hypertension: an individual participant data meta-analysis.

BACKGROUND: Mutations in the gene encoding the bone morphogenetic protein receptor type II (BMPR2) are the commonest genetic cause of pulmonary arterial hypertension (PAH). However, the effect of BMPR2 mutations on clinical phenotype and outcomes remains uncertain. METHODS: We analysed individual participant data of 1550 patients with idiopathic, heritable, and anorexigen-associated PAH from eight cohorts that had been systematically tested for BMPR2 mutations. The primary outcome was the composite of death or lung transplantation. All-cause mortality was the secondary outcome. Hazard ratios (HRs) for death or transplantation and all-cause mortality associated with the presence of BMPR2 mutation were calculated using Cox proportional hazards models stratified by cohort. FINDINGS: Overall, 448 (29%) of 1550 patients had a BMPR2 mutation. Mutation carriers were younger at diagnosis (mean age 35·4 [SD 14·8] vs 42·0 [17·8] years), had a higher mean pulmonary artery pressure (60·5 [13·8] vs 56·4 [15·3] mm Hg) and pulmonary vascular resistance (16·6 [8·3] vs 12·9 [8·3] Wood units), and lower cardiac index (2·11 [0·69] vs 2·51 [0·92] L/min per m(2); all p<0·0001). Patients with BMPR2 mutations were less likely to respond to acute vasodilator testing (3% [10 of 380] vs 16% [147 of 907]; p<0·0001). Among the 1164 individuals with available survival data, age-adjusted and sex-adjusted HRs comparing BMPR2 mutation carriers with non-carriers were 1·42 (95% CI 1·15-1·75; p=0·0011) for the composite of death or lung transplantation and 1·27 (1·00-1·60; p=0·046) for all-cause mortality. These HRs were attenuated after adjustment for potential mediators including pulmonary vascular resistance, cardiac index, and vasoreactivity. HRs for death or transplantation and all-cause mortality associated with BMPR2 mutation were similar in men and women, but higher in patients with a younger age at diagnosis (p=0·0030 for death or transplantation, p=0·011 for all-cause mortality). INTERPRETATION: Patients with PAH and BMPR2 mutations present at a younger age with more severe disease, and are at increased risk of death, and death or transplantation, compared with those without BMPR2 mutations. FUNDING: Cambridge NIHR Biomedical Research Centre, Medical Research Council, British Heart Foundation, Assistance Publique-Hôpitaux de Paris, INSERM, Université Paris-Sud, Intermountain Research and Medical Foundation, Vanderbilt University, National Center for Advancing Translational Sciences, National Institutes of Health, National Natural Science Foundation of China, and Beijing Natural Science Foundation.

Loss of HOXD10 expression induced by upregulation of miR-10b accelerates the migration and invasion activities of ovarian cancer cells.

Small and large non-coding RNAs (ncRNAs) contribute to the acquisition of aggressive tumor behavior in diverse human malignancies. Two types of ncRNAs, miRNA­10b (miR-10b) and homemobox (HOX) transcript antisense RNA (HOTAIR), can suppress the translation of the HOXD10 gene, an mRNA encoding a transcriptional repressor that inhibits the expression of cell migration/invasion-associated genes. Using epithelial ovarian cancer cell lines and primary tumors, we investigated whether miR­10b and/or HOTAIR can regulate the expression of HOXD10, and whether it permits gain of pro­metastatic gene products, matrix metallopeptidase 14 (MMP14) and ras homolog family member C (RHOC). Overexpression of miR-10b induced a decrease in HOXD10 protein expression, and upregulated the migration and invasion abilities in ovarian cancer cell lines (P<0.05). In these cells, a significant increase of MMP14 and RHOC protein was observed. No significant upregulation of the HOXD10 protein was observed in cells with the treatment of HOTAIR-siRNA. Positive signals for HOXD10 and MMP14 proteins were observed in 47 (69%) and 25 (37%) of 68 patients with epithelial ovarian cancers. An inverse correlation between HOXD10 and MMP14 immunoreactivities was observed (P<0.05), and miR-10b expression was also inversely correlated with HOXD10 protein expression (P<0.05). These results suggested that downregulation of HOXD10 expression by miR-10b overexpression may induce an increase of pro-metastatic gene products, such as MMP14 and RHOC, and contribute to the acquisition of metastatic phenotypes in epithelial ovarian cancer cells.

Transcriptional and post-transcriptional regulation of ßIII-tubulin protein expression in relation with cell cycle-dependent regulation of tumor cells.

The expression of ßIII-tubulin (TUBB3) is generally restricted to neurons, but its mRNA is often expressed at low levels in non-neuronal cells. Interestingly, however, a number of non-neural tumors occasionally express high levels of TUBB3 protein, leading to a significant resistance to taxane derivatives. However, the molecular mechanisms controlling TUBB3 expression and its turnover during normal cell growth are largely unknown. Here, we present evidence that TUBB3 expression occurs in a cell cycle-dependent manner, and that its protein levels are controlled by the ubiquitin-proteasome system. Both mRNA and protein of TUBB3 accumulated around the G2/M stage of the cell cycle, and reduction of TUBB3 expression by siRNA resulted in partial inhibition of cell growth. Furthermore, the cell cycle-dependent expression of TUBB3 was mediated by the RE-1-silencing transcription factor REST through its binding to the RE-1 element that is present in the first intron of the TUBB3 gene. These results demonstrate a novel role of TUBB3 in cell cycle progression in non-neuronal cells, and further suggest that dysregulation of the REST-TUBB3 system could be a primary cause of the TUBB3 overexpression.