Expression of the PAX8/PPARγ Fusion Protein Is Associated with Decreased Neovascularization In Vivo: Impact on Tumorigenesis and Disease Prognosis.
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ABSTRACT:
SUBMITTER: Reddi HV
PROVIDER: S-EPMC2934914 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:ContextA subset of thyroid carcinomas expresses an oncogenic paired box 8 (PAX8) and peroxisome proliferator activated receptor γ (PPARγ) fusion protein (PPFP). The PPARγ/PPFP ligand pioglitazone is highly therapeutic in a transgenic mouse model of PPFP thyroid carcinoma, but whether pioglitazone is therapeutic in patients with PPFP thyroid carcinoma is unknown.Case descriptionTumor blocks from 40 patients with progressive thyroid cancer despite standard-of-care therapy were screened for PPFP, and the tumor from only one patient (2.5%) was positive. The patient had a 6.0-cm acetabular soft tissue metastasis from Hürthle cell carcinoma that caused severe pain on weight bearing and had a serum thyroglobulin level of 1974 ng/mL. After 24 weeks of therapy with pioglitazone, the metastatic lesion was 3.9 cm, the thyroglobulin level was 49.4 ng/mL, and the patient was pain-free. Thirteen months after discontinuation of pioglitazone, the metastatic lesion was 3.6 cm, the thyroglobulin level was 4.7 ng/mL, and the patient remained pain-free.ConclusionsPioglitazone may be therapeutic in patients with PPFP thyroid cancer. However, thyroid cancers that are progressive despite standard-of-care therapy appear to only rarely express PPFP.
| S-EPMC6456920 | biostudies-literature
Project description:Calpains are a family of intracellular cysteine proteases involved in various biological processes. Previously, the family was identified to have abnormal expression in several types of malignant tumor. Calpain 6 was less well known; however, it was recently identified to be involved in the carcinogenesis of certain types of malignant tumor. However, the expression of calpain 6 in head and neck squamous cell carcinoma (HNSCC) remains unclear. A total of six datasets from the Gene Expression Omnibus (GEO) was analyzed and an association between calpain 6 expression levels and HNSCC was identified, with the expression of calpain 6 observed to be significantly decreased in HNSCC (P<0.01). However, the expression of calpain 6 may vary between distinct tumor stages of HNSCC. Furthermore, calpain 6 expression was positively associated with the survival rate in patients with HNSCC (P<0.05), with increased expression of calpain 6 associated with an improved survival outcome. Calpain 6 expression was analyzed using an HNSCC tissue microarray and these results were consistent with the statistical analysis of the bioinformatics data from the GEO, indicating that calpain 6 may be a tumor suppressor protein in HNSCC.
| S-EPMC5403261 | biostudies-literature
Project description:A subset of thyroid carcinomas contains a t(2;3)(q13;p25) chromosomal translocation that fuses paired box gene 8 (PAX8) with the peroxisome proliferator-activated receptor γ gene (PPARG), resulting in expression of a PAX8-PPARγ fusion protein, PPFP. We previously generated a transgenic mouse model of PPFP thyroid carcinoma and showed that feeding the PPARγ agonist pioglitazone greatly decreased the size of the primary tumor and prevented metastatic disease in vivo The antitumor effect correlates with the fact that pioglitazone turns PPFP into a strongly PPARγ-like molecule, resulting in trans-differentiation of the thyroid cancer cells into adipocyte-like cells that lose malignant character as they become more differentiated. To further study this process, we performed cell culture experiments with thyrocytes from the PPFP mouse thyroid cancers. Our data show that pioglitazone induced cellular lipid accumulation and the expression of adipocyte marker genes in the cultured cells, and shRNA knockdown of PPFP eliminated this pioglitazone effect. In addition, we found that PPFP and thyroid transcription factor 1 (TTF-1) physically interact, and that these transcription factors bind near each other on numerous target genes. TTF-1 knockdown and overexpression studies showed that TTF-1 inhibits PPFP target gene expression and impairs adipogenic trans-differentiation. Surprisingly, pioglitazone repressed TTF-1 expression in PPFP-expressing thyrocytes. Our data indicate that TTF-1 interacts with PPFP to inhibit the pro-adipogenic response to pioglitazone, and that the ability of pioglitazone to decrease TTF-1 expression contributes to its pro-adipogenic action.
| S-EPMC5016669 | biostudies-literature
Project description:Paired-box family member PAX8 encodes a transcription factor that has a role in cell differentiation and cell growth and may participate in the prognosis of hepatocellular carcinoma (HCC). By bioinformatics analysis, we identified several single nucleotide polymorphisms (SNPs) within a newly identified long non-coding RNA (lncRNA) AC016683.6 as expression quantitative trait loci (eQTLs) for PAX8. Hence, we hypothesized that PAX8eQTLs in lncRNA AC016683.6 may influence the HCC prognosis. We then performed a case-only study to assess the association between the two SNPs as well as the prognosis of HCC in 331 HBV-positive HCC patients without surgical treatment. Cox proportional hazard models were used for survival analysis with adjustments for the age, gender, smoking status, drinking status, Barcelona-Clinic Liver Cancer (BCLC) stage, and chemotherapy or TACE (transcatheter hepatic arterial chemoembolization) status. We found that the G allele of rs1110839 and the T allele of rs4848320 in PAX8was significantly associated with a better prognosis compared with the T allele of rs1110839 and the C allele of rs4848320 (adjusted HR = 0.74, 95% CI = 0.61-0.91, P = 0.004 for rs1110839 and adjusted HR = 0.71, 95% CI = 0.54-0.94, P = 0.015 for rs4848320 in the additive model). Furthermore, the combined effect of the variant genotypes for these two SNPs was more prominent in patients with the BCLC-C stage orpatients with chemotherapy or TACE. Although the exact biological function remains to be explored, our findings suggest a possible association of PAX8eQTLs in lncRNA AC016683.6 with the HCC prognosis inthe Chinese population. Further large and functional studies are needed to confirm our findings.
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Project description:UnlabelledCystathionine β-synthase (CBS) catalyzes metabolic reactions that convert homocysteine to cystathionine. To assess the role of CBS in human glioma, cells were stably transfected with lentiviral vectors encoding shRNA targeting CBS or a nontargeting control shRNA, and subclones were injected into immunodeficient mice. Interestingly, decreased CBS expression did not affect proliferation in vitro but decreased the latency period before rapid tumor xenograft growth after subcutaneous injection and increased tumor incidence and volume following orthotopic implantation into the caudate-putamen. In soft-agar colony formation assays, CBS knockdown subclones displayed increased anchorage-independent growth. Molecular analysis revealed that CBS knockdown subclones expressed higher basal levels of the transcriptional activator hypoxia-inducible factor 2α (HIF2α/EPAS1). HIF2α knockdown counteracted the effect of CBS knockdown on anchorage-independent growth. Bioinformatic analysis of mRNA expression data from human glioma specimens revealed a significant association between low expression of CBS mRNA and high expression of angiopoietin-like 4 (ANGPTL4) and VEGF transcripts, which are HIF2 target gene products that were also increased in CBS knockdown subclones. These results suggest that decreased CBS expression in glioma increases HIF2α protein levels and HIF2 target gene expression, which promotes glioma tumor formation.ImplicationsCBS loss-of-function promotes glioma growth.
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Project description:A chromosomal translocation results in production of an oncogenic PAX8-PPARG fusion protein (PPFP) in thyroid carcinomas. PAX8 is a thyroid transcription factor, and PPARG is a transcription factor that plays important roles in adipocytes and macrophages. PPFP retains the DNA binding domains of both proteins; however, the genomic binding sites of PPFP have not been identified, and only limited data exist to characterize gene expression in PPFP thyroid carcinomas. Therefore, the oncogenic function of PPFP is poorly understood. We expressed PPFP in PCCL3 rat thyroid cells and used ChIP-seq to identify PPFP genomic binding sites (PPFP peaks) and RNA-seq to characterize PPFP-dependent gene expression. PPFP peaks (~20,000) include known PAX8 and PPARG binding sites and are enriched with both motifs, indicating that both DNA binding domains are functional. PPFP binds to and regulates many genes involved in cancer-related processes. In PCCL3 thyroid cells, PPFP binds to adipocyte PPARG target genes in preference to macrophage PPARG target genes, consistent with the pro-adipogenic nature of PPFP and its ligand pioglitazone in thyroid cells. PPFP induces oxidative stress in thyroid cells, and pioglitazone increases susceptibility to further oxidative stress. Our data highlight the complexity of PPFP as a transcription factor and the numerous ways that it regulates thyroid oncogenesis.
| S-EPMC4747342 | biostudies-literature
Project description:Hyalinizing trabecular tumors of the thyroid are rare and mostly benign epithelial neoplasms of follicular cell origin, which have recently been shown to be underpinned by the PAX8-GLIS3 fusion gene. In our study, we sought to investigate the potential oncogenic mechanisms of the PAX8-GLIS3 fusion gene. Forced expression of PAX8-GLIS3 was found to increase proliferation, clonogenic potential and migration of human nonmalignant thyroid (Nthy-ori 3-1) and embryonic kidney (HEK-293) cells. Moreover, in xenografts, Nthy-ori 3-1 PAX8-GLIS3 expressing cells generated significantly larger and more proliferative tumors compared to controls. These oncogenic effects were found to be mediated through activation of the Sonic Hedgehog (SHH) pathway. Targeting of smoothened (SMO), a key protein in the SHH pathway, using the small molecule inhibitor Cyclopamine partially reversed the increased proliferation, colony formation and migration in PAX8-GLIS3 expressing cells. Our data demonstrate that the oncogenic effects of the PAX8-GLIS3 fusion gene are, at least in part, due to an increased activation of the SHH pathway.
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Project description:For the first time, dramatically decreased Dp71 protein and mRNA was found in 34 pairs of resected primary gastric adenocarcinoma. Immunohistochemistry identified Dp71 expression suppressed in 72.2% of 104 gastric cancer patients. The decreased Dp71 expression was significantly correlated with cancer differentiation (P=0.001) and lymph vascular invasion (p=0.041). Decreased Dp71 expression was associated with a poor gastric adenocarcinoma prognosis (P=0.001). Significantly less Dp71 mRNA and protein were found in BGC823, SGC7901, AGS compared with GES-1. Via increasing lamin B1 mRNA and protein, enforced Dp71d and Dp71f expression resulted in SGC7901 proliferation inhibition. Co-IP proved interaction of Dp71 with lamin B1 in GES-1 cells. Further expression characterization showed reduced lamin B1 in gastric cancer tissue and cancer cells. Increasing lamin B1 expression results in the growth inhibition of SGC7901, which suggests that Dp71-lamin B1 protein complex plays an important role for the newly identified tumor suppressive function of Dp71.
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Project description:Angiogenesis is a key process in several ocular disorders and cancers. Soluble Flt-1 is an alternatively spliced form of the Flt-1 gene that retains the ligand-binding domain, but lacks the membrane-spanning and intracellular kinase domains of the full-length membrane bound Flt-1 (mbFlt-1) protein. Thus, sFlt-1 is an endogenous inhibitor of VEGF-A mediated angiogenesis. Synthetic mopholino oligomers directed against splice site targets can modulate splice variant expression. We hypothesize that morpholino-induced upregulation of sFlt-1 will suppress angiogenesis in clinically relevant models of macular degeneration and breast cancer.In vivo morpholino constructs were designed to target murine exon/intron 13 junction of the Flt-1 transcript denoted VEGFR1_MOe13; standard nonspecific morpholino was used as control. After nucleofection of endothelial and breast adenocarcinoma cell lines, total RNA was extracted and real-time RT-PCR performed for sFlt-1 and mbFlt-1. Intravitreal injections of VEGFR1_MOe13 or control were done in a model of laser-induced choroidal neovascularization and intratumoral injections were performed in MBA-MD-231 xenografts in nude mice. VEGFR1_MOe13 elevated sFlt-1 mRNA expression and suppressed mbFlt-1 mRNA expression in vitro in multiple cellular backgrounds (p<0.001). VEGFR1_MOe13 also elevated sFlt/mbFlt-1 ratio in vivo after laser choroidal injury 5.5 fold (p<0.001) and suppressed laser-induced CNV by 50% (p = 0.0179). This latter effect was reversed by RNAi of sFlt-1, confirming specificity of morpholino activity through up-regulation of sFlt-1. In the xenograft model, VEGFR1_MOe13 regressed tumor volume by 88.9%, increased sFlt-1 mRNA expression, and reduced vascular density by 50% relative to control morpholino treatment (p<0.05).Morpholino oligomers targeting the VEGFR1 mRNA exon/intron 13 junction promote production of soluble FLT-1 over membrane bound FLT-1, resulting in suppression of lesional volume in laser induced CNV and breast adenocarcinoma. Thus, morpholino manipulation of alternative splicing offers translational potential for therapy of angiogenic disorders.
| S-EPMC3305322 | biostudies-literature
Project description:High-grade serous ovarian carcinoma (HGSOC) is usually diagnosed at a late stage and is associated with poor prognosis. Understanding early stage disease biology is essential in developing clinical biomarkers to detect HGSOC earlier. While recent studies indicate that HGSOCs arise from fallopian tube secretory epithelial cells, a considerable body of evidence suggests that HGSOC can also arise from ovarian surface epithelial cells (OSECs). PAX8 is overexpressed in HGSOCs and expressed in fallopian tube secretory epithelial cells, but there are conflicting reports about PAX8 expression in OSECs. The purposes of this study were to comprehensively characterize PAX8 expression in a large series of OSECs and to investigate the role of PAX8 in early HGSOC development. PAX8 protein expression was analyzed in the OSECs of 27 normal ovaries and 7 primary OSEC cultures using immunohistochemistry and immunofluorescent cytochemistry. PAX8 messenger RNA expression was quantified in 66 primary OSEC cultures. Cellular transformation was evaluated in OSECs expressing a PAX8 construct. PAX8 was expressed by 44% to 71% of OSECs. Calretinin and E-cadherin were frequently coexpressed with PAX8. Expression of PAX8 in OSECs decreased cellular migration (P = .028), but had no other effects on cellular transformation. In addition, PAX8 expression was significantly increased (P = .003) in an in vitro stepwise model of neoplastic transformation. In conclusion, PAX8 is frequently expressed by OSECs, and endogenous levels of PAX8 expression are non-transforming. These data indicate that in OSECs, PAX8 expression may represent a normal state and that OSECs may represent an origin of HGSOCs.
| S-EPMC4951208 | biostudies-literature