Motohide Uemura

Association of a novel long non-coding RNA in 8q24 with prostate cancer susceptibility

Recent genome‐wide association studies reported strong and reproducible associations of multiple genetic variants in a large “gene‐desert” region of chromosome 8q24 with susceptibility to prostate cancer (PC). However, the causative or functional variants of these 8q24 loci and their biological mechanisms associated with PC susceptibility remain unclear and should be investigated. Here, focusing on its most centromeric region (so‐called Region 2: Chr8: 128.14‐128.28 Mb) among the multiple PC loci on 8q24, we performed fine mapping and re‐sequencing of this critical region and identified SNPs (single nucleotide polymorphisms) between rs1456315 and rs7463708 (chr8: 128,173,119‐128,173,237 bp) to be most significantly associated with PC susceptibility (P = 2.00 × 10−24, OR = 1.74, 95% confidence interval = 1.56–1.93). Importantly, we show that this region was transcribed as a ∼13 kb intron‐less long non‐coding RNA (ncRNA), termed PRNCR1 (prostate cancer non‐coding RNA 1), and PRNCR1 expression was upregulated in some of the PC cells as well as precursor lesion prostatic intraepithelial neoplasia. Knockdown of PRNCR1 by siRNA attenuated the viability of PC cells and the transactivation activity of androgen receptor, which indicates that PRNCR1 could be involved in prostate carcinogenesis possibly through androgen receptor activity. These findings could provide a new insight in understanding the pathogenesis of genetic factors for PC susceptibility and prostate carcinogenesis. (Cancer Sci 2011; 102: 245–252)

Novel 5α‐steroid reductase (SRD5A3, type‐3) is overexpressed in hormone‐refractory prostate cancer

Prostate cancer often relapses during androgen‐depletion therapy, even under conditions in which a drastic reduction of circulating androgens is observed. There is some evidence that androgens remain present in the tissues of hormone‐refractory prostate cancers (HRPC), and enzymes involved in the androgen and steroid metabolic pathway are likely to be active in HRPC cells. We previously carried out a genome‐wide gene expression profile analysis of clinical HRPC cells by means of cDNA microarrays in combination with microdissection of cancer cells and found dozens of transactivated genes. Among them, we here report the identification of a novel gene, SRD5A2L, encoding a putative 5α‐steroid reductase that produces the most potent androgen, 5α‐dihydrotestosterone (DHT), from testosterone. Liquid chromatography‐tandem mass spectrometry analysis following an in vitro 5α‐steroid reductase reaction validated its ability to produce DHT from testosterone, similar to type 1 5α‐steroid reductase. Because two types of 5α‐steroid reductase were previously reported, we termed this novel 5α‐steroid reductase ‘type 3 5α‐steroid reductase’ (SRD5A3). Reverse transcription–polymerase chain reaction and northern blot analyses confirmed its overexpression in HRPC cells, and indicated no or little expression in normal adult organs. Knockdown of SRD5A3 expression by small interfering RNA in prostate cancer cells resulted in a significant decrease in DHT production and a drastic reduction in cell viability. These findings indicate that a novel type 3 5α‐steroid reductase, SRD5A3, is associated with DHT production and maintenance of androgen–androgen receptor‐pathway activation in HRPC cells, and that this enzymatic activity should be a promising molecular target for prostate cancer therapy. (Cancer Sci 2008; 99: 81–86)

Hyperbaric oxygen therapy for radiation-induced hemorrhagic cystitis

Abstract:  Hyperbaric oxygen (HBO) therapy has recently emerged as a potential primary option for the management of hemorrhagic cystitis. We review our experience treating hemorrhagic cystitis with HBO. Between January 2001 and May 2007, eight patients with radiation‐induced hemorrhagic cystitis underwent HBO therapy. There were five men and three women with a mean age of 64.3 years (47–73). Radiation was given for local disease, and the mean dosage delivered was 56.6 Gy (42–70). The mean duration between the onset of hematuria and the beginning of HBO therapy was 8.9 months (3–34). Mean follow‐up period was 15.5 months (2–31). Hematuria resolved completely in six of the eight patients, one of whom suffered recurrence of hematuria and was treated with HBO until the hematuria resolved again. The response rate was 75%, compatible with the previous reports, and no side‐effects of HBO were noted. HBO treatment should be attempted for radiation‐induced hemorrhagic cystitis.

Stanniocalcin 2 overexpression in castration-resistant prostate cancer and aggressive prostate cancer.

Prostate cancer is usually androgen‐dependent and responds well to androgen ablation therapy based on castration. However, at a certain stage some prostate cancers eventually acquire a castration‐resistant phenotype where they progress aggressively and show very poor response to any anticancer therapies. To characterize the molecular features of these clinical castration‐resistant prostate cancers, we previously analyzed gene expression profiles by genome‐wide cDNA microarrays combined with microdissection and found dozens of trans‐activated genes in clinical castration‐resistant prostate cancers. Among them, we report the identification of a new biomarker, stanniocalcin 2, as an overexpressed gene in castration‐resistant prostate cancer cells. Real‐time polymerase chain reaction and immunohistochemical analysis confirmed overexpression of stanniocalcin 2, a 302‐amino‐acid glycoprotein hormone, specifically in castration‐resistant prostate cancer cells and aggressive castration‐naïve prostate cancers with high Gleason scores (8–10). The gene was not expressed in normal prostate, nor in most indolent castration‐naïve prostate cancers. Knockdown of stanniocalcin 2 expression by short interfering RNA in a prostate cancer cell line resulted in drastic attenuation of prostate cancer cell growth. Concordantly, stanniocalcin 2 overexpression in a prostate cancer cell line promoted prostate cancer cell growth, indicating its oncogenic property. These findings suggest that stanniocalcin 2 could be involved in aggressive phenotyping of prostate cancers, including castration‐resistant prostate cancers, and that it should be a potential molecular target for development of new therapeutics and a diagnostic biomarker for aggressive prostate cancers. (Cancer Sci 2009; 100: 914–919)

The miR-130 family promotes cell migration and invasion in bladder cancer through FAK and Akt phosphorylation by regulating PTEN.

Bladder cancer causes an estimated 150,000 deaths per year worldwide. Although 15% of the recurrent bladder cancer becomes an invasive type, currently used targeted therapy for malignant bladder cancer is still not efficient. We focused on the miR-130 family (miR-130b, miR-301a, and miR-301b) that was significantly upregulated in bladder cancer specimens than that of the normal urothelial specimens. We analyzed the functional significance of miR-130 family using a 5637 bladder cancer cell line and revealed that miR-130 family of inhibitors suppressed cell migration and invasion by downregulating focal adhesion kinase (FAK) and Akt phosphorylation. Mechanistic analyses indicate that the miR-130 family directly targets phosphatase and tensin homolog deleted from chromosome 10 (PTEN), resulting in the upregulation of FAK and Akt phosphorylation. In clinical bladder cancer specimens, downregulation of PTEN was found to be closely correlated with miR-130 family expression levels. Overall, the miR-130 family has a crucial role in malignant progression of bladder cancer and thus the miR-130 family could be a promising therapeutic target for invasive bladder cancer.

EMMPRIN Promotes Angiogenesis, Proliferation, Invasion and Resistance to Sunitinib in Renal Cell Carcinoma, and Its Level Predicts Patient Outcome

Purpose Extracellular matrix metalloproteinase inducer (EMMPRIN) has been reported to play crucial roles, including in angiogenesis, in several carcinomas. However, the correlation between EMMPRIN levels and angiogenesis expression profile has not been reported, and the role of EMMPRIN in renal cell carcinoma (RCC) is unclear. In the present study, we evaluated the association of EMMPRIN with angiogenesis, its value in prognosis, and its roles in RCC. Experimental Design EMMPRIN expression was examined in 50 RCC patients treated with radical nephrectomy. Angiogenesis, proliferation, and invasion activity were evaluated using EMMPRIN knockdown RCC cell lines. The size of EMMPRIN-overexpressing xenografts was measured and the degree of angiogenesis was quantified. EMMPRIN expression was evaluated in RCC patients who received sunitinib therapy and in sunitinib-resistant cells. Further, the relation between EMMPRIN expression and sensitivity to sunitinib was examined. Results EMMPRIN score was significantly associated with clinicopathological parameters in RCC patients, as well as being significantly correlated with microvessel area (MVA) in immature vessels and with prognosis. Down-regulation of EMMPRIN by siRNA led to decreased VEGF and bFGF expression, cell proliferation, and invasive potential. EMMPRIN over-expressing xenografts showed accelerated growth and MVA of immature vessels. EMMPRIN expression was significantly increased in patients who received sunitinib therapy as well as in sunitinib-resistant 786-O cells (786-suni). EMMPRIN-overexpressing RCC cells were resistant to sunitinib. Conclusion Our findings indicate that high expression of EMMPRIN in RCC plays important roles in tumor progression and sunitinib resistance. Therefore, EMMPRIN could be a novel target for the treatment of RCC.

Overexpressing PKIB in prostate cancer promotes its aggressiveness by linking between PKA and Akt pathways.

Prostate cancer (PC) is the most common malignancy in males. Despite high response rates and clinical benefits, androgen-ablation therapy is ineffective for advanced or relapsed PC because of the emergence of aggressive castration-resistant prostate cancer (CRPC). Through our genome-wide gene expression analysis of PC cells purified from clinical CRPC tissues, we here identified a novel molecular target, PKIB (cAMP-dependent protein kinase inhibitor-β), which was overexpressed specifically in CRPCs and aggressive PCs. Immunohistochemical analysis confirmed its overexpression in CRPCs and its strong correlation with high Gleason scores of PCs. Knockdown of PKIB by siRNA resulted in drastic growth suppression of PC cells, and, concordantly, exogenous introduction of PKIB into PC cells enhanced their growth and mobility. We found the direct interaction between PKIB and cAMP-dependent protein kinase A catalytic subunit (PKA-C), and showed that knockdown of PKIB in PC cells diminished the nuclear translocation of PKA-C. Knockdown of PKIB also decreased the phosphorylation level of Akt at Ser473 in PC cells, and exogenous PKIB introduction enhanced Akt phosphorylation in PC cells by incorporating with endogenous PKA-C kinase. In vitro kinase assay validated the recombinant PKIB enhanced phosphorylation of Akt at Ser473 by PKA-C kinase. These findings show that PKIB and PKA-C kinase can have critical functions of aggressive phenotype of PCs through Akt phosphorylation and that they should be a promising molecular target for PC treatment.

Serum fucosylated haptoglobin as a novel prognostic biomarker predicting high-Gleason prostate cancer

Fucosylation is an oligosaccharide modification associated with cancer and inflammation, which is catalyzed by fucosyltransferases. Fucosylated haptoglobin (Fuc‐Hpt) has been identified as a novel biomarker for pancreatic cancer.

Impact of hyponatremia on survival of patients with metastatic renal cell carcinoma treated with molecular targeted therapy

Objectives:  Hyponatremia is reported to be associated with poor survival in localized renal cell carcinoma and metastatic renal cell carcinoma treated with immunotherapy. However, there are no reports on the relationship between hyponatremia and prognosis of metastatic renal cell carcinoma treated with molecular targeted therapy. We evaluated the prognostic significance of hyponatremia in metastatic renal cell carcinoma treated with molecular targeted therapy as first‐line therapy.

miR-629 Targets TRIM33 to Promote TGFβ/Smad Signaling and Metastatic Phenotypes in ccRCC

Renal cell carcinoma (RCC) is the most common neoplasm of the adult kidney, and clear cell RCC (ccRCC) represents its most common histological subtype. To identify a therapeutic target for ccRCC, miRNA expression signatures from ccRCC clinical specimens were analyzed. miRNA microarray and real-time PCR analyses revealed that miR-629 expression was significantly upregulated in human ccRCC compared with adjacent noncancerous renal tissue. Functional inhibition of miR-629 by a hairpin miRNA inhibitor suppressed ccRCC cell motility and invasion. Mechanistically, miR-629 directly targeted tripartite motif-containing 33 (TRIM33), which inhibits the TGFβ/Smad signaling pathway. In clinical ccRCC specimens, downregulation of TRIM33 was observed with the association of both pathologic stages and grades. The miR-629 inhibitor significantly suppressed TGFβ-induced Smad activation by upregulating TRIM33 expression and subsequently inhibited the association of Smad2/3 and Smad4. Moreover, a miR-629 mimic enhanced the effect of TGFβ on the expression of epithelial–mesenchymal transition–related factors as well as on the motility and invasion in ccRCC cells. These findings identify miR-629 as a potent regulator of the TGFβ/Smad signaling pathway via TRIM33 in ccRCC. Implications: This study suggests that miR-629 has biomarker potential through its ability to regulate TGFβ/Smad signaling and accelerate ccRCC cell motility and invasion. Mol Cancer Res; 13(3); 565–74. ©2014 AACR.