Correction: Genistein downregulates onco-miR-1260b and upregulates sFRP1 and Smad4 via demethylation and histone modification in prostate cancer cells.

The authors report that there is a mistake in the representative picture of Fig. 4D (top row: PC3-miR1260b inh-0h) in the original version. The correct version of Fig. 4 with the original pictures for both PC3 miR-NC inh-0h and PC3-miR1260b inh-0h are provided below.

Genistein downregulates onco-miR-1260b and upregulates sFRP1 and Smad4 via demethylation and histone modification in prostate cancer cells.

BACKGROUND: Recently several microRNAs (miRNAs) have been found to be regulated by genistein in cancer cells. In this study, we focused on the gene regulatory effect of genistein on microRNA and its target genes in prostate cancer (PC). METHODS: Initially, we investigated the effect of genistein on prostate cancer cells and identified that the expression of miRNA-1260b was decreased by genistein. We performed functional analyses and investigated the relationship between miRNA-1260b expression and prostate cancer patient outcomes. Two target genes (sFRP1 and Smad4) of miR-1260b were identified based on computer algorithm and 3'UTR luciferase assay was carried out to determine direct miRNA regulation of the genes. RESULTS: Genistein promoted apoptosis while inhibiting prostate cancer cell proliferation, invasion and TCF reporter activity in PC cells. MiR-1260b was highly expressed in prostate cancer tissues and significantly downregulated by genistein in PC cells. After knocking down miR-1260b, cell proliferation, invasion, migration and TCF reporter activity were decreased in PC cells. Western analysis and 3'UTR luciferase assay showed that the two target genes (sFRP1 and Smad4) were directly regulated by miR-1260b. The expression of sFRP1 and Smad4 was significantly decreased in prostate cancer tissues. Genistein also increased expression of these two genes via DNA demethylation and histone modifications. CONCLUSIONS: Our data suggest that genistein exerts its anti-tumour effect via downregulation of miR-1260b that targeted sRRP1 and Smad4 genes in prostate cancer cells. The expression of sFRP1 and Smad4 was also modulated by genistein via DNA methylation or histone modifications in PC cell lines.

microRNA-183 is an oncogene targeting Dkk-3 and SMAD4 in prostate cancer.

BACKGROUND: The purpose of this study was to identify prostate cancer (PC) oncogenic microRNAs (miRs) based on miR microarray and to investigate whether these oncogenic miRs may be useful as PC biomarkers. METHODS: Initially, we carried out miR microarray and real-time PCR using RWPE-1, PC-3, DU-145 and LNCaP cells. To investigate the function of miR-183, we used a miR-183 knockdown inhibitor in cell growth and wound-healing assays. We used several algorithms and confirmed that they are directly regulated by miR-183. RESULTS: We identified three potential oncogenic miRs (miR-146a, miR-183 and miR-767-5P). The expression of miR-183 in PC cells (PC-3, DU-145 and LNCaP) was upregulated compared with RWPE-1 cells. MiR-183 expression was also significantly higher in PC tissues compared with that in matched normal prostate tissues. Additionally, miR-183 expression was correlated with higher prostate-specific antigen, higher pT and shorter overall survival. MiR-183 knockdown decreased cell growth and motility in PC cells and significantly decreased prostate tumour growth in in vivo nude mice experiments. We identified Dkk-3 and SMAD4 as potential target genes of miR-183. CONCLUSION: Our data suggest that oncogenic miR-183 may be useful as a new PC biomarker and that inhibition of miR-183 expression may be therapeutically beneficial as a PC treatment.

Genistein downregulates onco-miR-1260b and inhibits Wnt-signalling in renal cancer cells.

BACKGROUND: Wnt-signalling has an important role in renal cancer and it is modulated by genistein in other cancers. Recently, microRNAs (miRNAs) have emerged as new regulators of gene expression. Thus, we focused on miRNAs to examine the regulatory mechanism of genistein on the Wnt-signalling pathway in renal cell carcinoma (RCC). METHODS: Initially, we investigated the effect of genistein on Wnt-signalling (TOPflash reporter assay (TCF reporter assays)) in renal cancer cells, and using microarray identified candidate miRNAs whose expression was decreased by genistein. We performed functional analyses and investigated the relationship between miRNA expression and renal cancer patient outcomes. We also did 3'UTR luciferase assays to look at direct miRNA regulation of Wnt-signalling-related genes. RESULTS: Genistein promoted apoptosis while inhibiting RCC cell proliferation and invasion. Genistein also decreased TCF reporter activity in RCC cells. We found that miR-1260b was highly expressed and significantly downregulated by genistein in RCC cells. The expression of miR-1260b was significantly higher in renal cancer tissues compared with normal, and significantly related to overall shorter survival. In addition, miR-1260b promoted renal cancer cell proliferation and invasion in RCC cells. The 3'UTR luciferase activity of target genes (sFRP1, Dkk2, Smad4) was significantly decreased and their protein expression significantly upregulated in miR-1260b inhibitor-transfected renal cancer cells. CONCLUSION: Our data suggest that genistein inhibited Wnt-signalling by regulating miR-1260b expression in renal cancer cells.

Tumour suppressor microRNA-584 directly targets oncogene Rock-1 and decreases invasion ability in human clear cell renal cell carcinoma.

BACKGROUND: The purpose of this study was to identify new tumour suppressor microRNAs (miRs) in clear cell renal cell carcinoma (ccRCC), carry out functional analysis of their suppressive role and identify their specific target genes. METHODS: To explore suppressor miRs in RCC, miR microarray and real-time PCR were performed using HK-2 and A-498 cells. Cell viability, invasion and wound healing assays were carried out for functional analysis after miR transfection. To determine target genes of miR, we used messenger RNA (mRNA) microarray and target scan algorithms to identify target oncogenes. A 3'UTR luciferase assay was also performed. Protein expression of target genes in ccRCC tissues was confirmed by immunohistochemistry and was compared with miR-584 expression in ccRCC tissues. RESULTS: Expression of miR-584 in RCC (A-498 and 769-P) cells was downregulated compared with HK-2 cells. Transfection of miR-584 dramatically decreased cell motility. The ROCK-1 mRNA was inhibited by miR-584 and predicted to be target gene. The miR-584 decreased 3'UTR luciferase activity of ROCK-1 and ROCK-1 protein expression. Low expression of miR-584 in ccRCC tissues was correlated with high expression of ROCK-1 protein. The knockdown of ROCK-1 by siRNA inhibited cell motility. CONCLUSION: miR-584 is a new tumour suppressor miR in ccRCC and inhibits cell motility through downregulation of ROCK-1.

Methylation level of the RASSF1A promoter is an independent prognostic factor for clear-cell renal cell carcinoma.

BACKGROUND: Ras association domain family 1A (RASSF1A) is a tumor suppressor that regulates the cell cycle, apoptosis, and microtubule stability. The association between the methylation levels of RASSF1A and the prognosis of clear-cell renal cell carcinoma (CCRCC) remains unclear. Therefore, we investigated this relationship to determine the prognostic value of RASSF1A methylation levels for CCRCC. PATIENTS AND METHODS: The study comprised 179 Japanese patients who underwent radical or partial nephrectomy for CCRCC. The methylation level of 5' CpG islands in the RASSF1A was evaluated using combined bisulfite restriction analysis and bisulfite sequencing. RESULTS: High levels of methylation in the RASSF1A promoter were significantly more frequent in grade 3 compared with grade 1 or 2 tumors (P = 0.028) and in patients with stage III or IV compared with patients with stage I or II (P = 0.043). Patients with high methylation levels had a significantly less favorable prognosis compared with those with low methylation levels (P = 0.040). Higher methylation levels were independently associated with a poor prognosis following multivariate analysis (P = 0.0053). CONCLUSION: These results indicate that quantitative promoter methylation levels of the RASSF1A gene may be a useful marker to predict the prognosis of CCRCC.

Down-regulation of frizzled-7 expression decreases survival, invasion and metastatic capabilities of colon cancer cells.

BACKGROUND: The canonical Wnt signalling pathway is activated in most sporadic colorectal cancers (CRCs). We previously reported that FZD7 functions as a receptor for the canonical Wnt signalling pathway in colon cancer cells. METHODS AND RESULTS: In this study, we examined the function of FZD7 in survival, invasion and metastatic capabilities of colon cancer cells. FZD7_siRNA transfection decreased cell viability of HT-29 and HCT-116 colon cancer cells. Expression of c-Jun, phosphorylation of JNK and c-Jun, and activation of RhoA were suppressed after FZD7_siRNA transfection into HCT-116 cells. In vitro invasion activity and Wnt target gene expression were also reduced in HCT-116 cells transfected with FZD7_siRNA. Liver metastasis of stable FZD7_siRNA HCT-116 cell transfectants in scid mice was decreased to 40-50% compared to controls. The mRNA levels of FZD7 in 135 primary CRC tissues were examined by real-time PCR. FZD7 mRNA levels were significantly higher in stage II, III or IV tumours than in non-tumour tissues (P<0.005), and overall survival was shorter in those patients with higher FZD7 expression (P<0.001). CONCLUSION: These data suggest that FZD7 may be involved in enhancement of survival, invasion and metastatic capabilities of colon cancer cells through non-canonical Wnt signalling pathways as well as the canonical pathway.

The association of DNA repair gene polymorphisms with the development and progression of renal cell carcinoma.

BACKGROUND: DNA repair enzymes repair some of the DNA damage associated with risk factors for renal cell carcinoma (RCC), including smoking. DNA repair gene polymorphisms modulate the repair capacity and might influence individual risk and progression of RCC. We examined associations between functional polymorphisms and risk, clinicopathologic characteristics and survival of RCC. PATIENTS AND METHODS: The study groups comprised 215 RCC patients and 215 age- and gender-matched healthy controls. Polymorphisms in xeroderma pigmentosum complementation groups C, D and G and X-ray repair cross-complementing groups 1 and 3 genes were genotyped. RESULTS: No significant differences in DNA repair genotype were observed between RCC cases and controls. In all patients, however, greater numbers (> or =3) of total variant alleles in all DNA repair genes studied were associated with less frequent venous extension (P = 0.0079). In smokers, some genotypes were associated with characteristics of RCC (Ps < or = 0.0067) and smokers with greater numbers of total variant alleles had improved overall survival (P = 0.040). CONCLUSION: These results suggest that DNA repair gene polymorphisms may not influence RCC susceptibility, but that some of them may influence RCC progression, especially in smokers, possibly due to altered DNA repair capacity by these polymorphisms.

Inverse association of cell adhesion regulator messenger RNA expression with metastasis in human colorectal cancer.

Alterations in several classes of adhesion molecules have been implicated in the progression of colorectal cancer. Cell adhesion regulator (CAR) has been identified as a regulator molecule of integrin-dependent cell adhesion. We have explored a possible involvement of the CAR gene in colorectal cancer. Reverse transcription-PCR revealed that CAR expression was detected in normal colonic cells, whereas it was decreased or undetectable in 6 of 13 (46.2%) human colon cancer cell lines. To further study the biological significance of CAR expression in colon cancer cells, a CAR expression vector was introduced into HT-29 cells, in which CAR is not expressed. Adhesion of HT-29 cells to extracellular matrix components was up-regulated by the introduction of CAR. In spite of similar growth properties with the controls, CAR-transfected HT-29 cells showed a significantly reduced spontaneous metastatic potential in nude mice. To determine whether these experimental results are of relevance with respect to actual human tumors, we investigated CAR expression in 30 surgical specimen pairs of human colorectal cancer and adjacent noncancerous tissue using semiquantitative reverse transcription-PCR. In 14 of 30 cases (46.7%), CAR expression in cancer was less than one-tenth of that in matched noncancerous tissue. The tumor:normal ratio of CAR expression was significantly lower in patients with lymph node metastasis than in those without it (P < 0.01) and in patients with distant metastasis than in those without it (P < 0.05). CAR expression was significantly lower in more advanced Dukes' stage tumors (P < 0.05). Our results suggest that down-regulation of CAR expression may play an important role in the progression and metastasis of colorectal cancer.

Complementary DNA cloning and characterization of truncated form of c-kit in human colon carcinoma cells.

We have obtained a novel c-kit complementary DNA (cDNA) from a colon carcinoma cell line, Colo201, and characterized its structure. The size of the transcript in Colo201 was approximately 3.5 kilobases and it hybridized to the c-kit cDNA fragments encompassing the kinase domain, but not to the cDNA fragments encoding extracellular and transmembrane domains. The predicted protein encoded by those cDNAs was composed of 257 amino acids containing the NH2-terminal 25 unique amino acids in frame by the COOH terminal of the KIT protein. Of interest, these 25 amino acids were encoded by intron 15 of the c-kit gene. The aberrant mRNA was also detected in another colon carcinoma cell line, BM314. The translation of this message in Colo201 was confirmed by flow cytometry and immunoblot analysis. This is the first report describing the aberrant transcript of c-kit in human tumor cells, and it is suggested that truncated form of c-kit might play a role in the onset and development of human colon carcinoma.

Induction of antigen-specific immune response with use of anti-idiotypic monoclonal antibodies to anti-carcinoembryonic antigen antibodies.

Anti-idiotypic monoclonal antibodies (MoAbs) were prepared in a syngeneic system against anti-carcinoembryonic antigen (CEA) MoAb 5B3 (IgG1), which reacted with a carbohydrate moiety on CEA, and MoAb MA208 (IgG1), which reacted with a peptide on CEA. Anti-idiotypic MoAb T3-503 and T4-202 recognized the private idiotype of MoAb 5B3; anti-idiotypic MoAb M7-049 and M7-625 did so for MoAb MA208. Idiotype mapping showed that MoAb 5B3 has at least two distinct idiotopes at its combining site and MoAb MA208 also has two. Four different anti-idiotypic MoAbs (Ab2) could induce anti-anti-idiotypic antibodies (Ab3) specific to their respective immunizing anti-idiotypic MoAbs. Anti-anti-idiotypic MoAb M7-625 antiserum (at least a part of the antibodies) have the same reactivity as MoAb MA208, since the serum competed with the binding of MoAb MA208 against CEA and contained the antibody population reactive with purified CEA in immunoblotting assay. These results suggest that anti-idiotypic MoAb M7-625 bears the internal image of the antigen (CEA) and induces the anti-anti-idiotypic antibodies specific to CEA. Therefore, an anti-idiotypic antibody bearing the internal image of a tumor associated antigen might be used as a possible tool for vaccination or immunotherapy against malignant tumors as an antigen specific immunomodulator.

Protein-tyrosine phosphatase expression in pre-B cell NALM-6.

Protein-tyrosine phosphatase (PTP)-related complementary DNAs from NALM-6 (pre-B cell line) were amplified by reverse transcriptase polymerase chain reaction using primers corresponding to the conserved catalytic domains of PTPs. Thirty-three polymerase chain reaction products, identified as PTP related complementary DNAs, were classified to RPTP-alpha, PTP1B, and 4 novel PTPs, which were designated as BPTP-1-4. Their expressions in NALM-6 and other cell lines were confirmed by Northern blot analysis. BPTP-1 and -2 exhibited extensive homology with the first and the second catalytic domains, respectively, of leukocyte common antigen related molecule (LAR) and human PTP delta. The transcriptional sizes of BPTP-1 and BPTP-2 are the same (7.2 kilobases) as that of LAR. The expression of BPTP-1 was abundant in lymphoid cell lines TALL-1 and NALM-6 but small in colon cell line BM314, which is in sharp contrast to the expression of LAR. These data suggest that the expression levels of BPTP-1 and LAR are altered in a cell specific manner, probably making them cell type associated PTPs.

Effective adoptive immunotherapy by T-LAK cells retargeted with bacterial superantigen-conjugated antibody to MUC1 in xenografted severe combined immunodeficient mice.

To reinforce cytotoxic activity and the targeting ability of lymphokine-activated killer cells with a T-cell phenotype (T-LAK) for adoptive immunotherapy against human bile duct carcinoma (BDC), staphylococcal enterotoxin A (SEA) was conjugated chemically with MUSE11 monoclonal antibody (MUSE11 mAb), directed to the MUC1 antigen, using N-succinimidyl 3-(2-pyridyldithio) propionate and 2-iminothiolane HCl. Both SEA-conjugated MUSE11 mAb (SEA-MUSE11) and the F(ab')2 of MUSE11 mAb (SEA-F(ab')2) showed significant enhancement of T-LAK cell tumor neutralization for MUC1 positive-target tumor cells, even with a concentration of 0.01 microg/ml at an E:T ratio of 5:1 in vitro. In this in vitro test, MUC1-positive BDC cells were observed to attach to surrounding T-LAK cells in the presence of SEA-MUSE11 or SEA-F(ab')2. Remarkable tumor growth inhibition was observed in BDC-grafted severe combined immunodeficient mice to which 2 x 10(7) T-LAK cells preincubated with 2 microg of SEA-MUSE11 or SEA-F(ab')2, together with recombinant interleukin 2 (500 IU), were administered i.v. for 4 consecutive days, when tumor size was 5 mm in diameter. These results point to a promising adoptive immunotherapy for patients with BDC.

Association of matrilysin expression with recurrence and poor prognosis in human esophageal squamous cell carcinoma.

Matrix metalloproteinase-7 (matrilysin) has been implicated in tumor invasion and metastasis as well as tumor initiation and growth. In this study, we analyzed an association between immunohistochemically detected matrilysin expression at the invasive front in esophageal squamous cell carcinomas and clinicopathological characteristics and determined whether matrilysin predicts recurrence and/or survival Matrilysin expression at the invasive front was detected in 49% of 100 carcinoma tissues and was associated with the depth of invasion (P < 0.0001), advanced tumor stage (P = 0.0159), recurrences (P = 0.0002), and recurrences within the first postoperative year (P = 0.002). Patients with matrilysin-positive carcinoma had a significantly shorter disease-free and overall survival time than did those with a matrilysin-negative one (P < 0.0001). Matrilysin remained a significant predictive value for disease-free and overall survival in multivariate analysis, including conventional clinicopathological factors (P = 0.0007 and 0.0004, respectively). Our results suggest that matrilysin may play a key role in the progression of esophageal carcinoma and that its detection may be useful for the prediction of recurrence and poor prognosis and, possibly, for selecting patients for anti-matrix metalloproteinase therapy.

Chromosomal localization of an SH2 containing tyrosine phosphatase (SH-PTP3) gene to chromosome 12q24.1.

A genomic DNA fragment, isolated from a human phage library using a human BPTP3 cDNA probe, was shown to be derived from the human SH-PTP3 (also called SH-PTP2, PTP-1D, PTP-2C, or Syp) locus. We have used fluorescent in situ hybridization (FISH) to map SH-PTP3 in chromosome band 12q24.1, a region vicinity to the second locus for autosomal dominant cerebellar ataxia (SCA2).

Structure of the human LC-PTP (HePTP) gene: similarity in genomic organization within protein-tyrosine phosphatase genes.

Recently, various cDNA sequences coding protein-tyrosine phosphatases (PTPs) have been reported and their extensive similarities in the catalytic domains clarified, but knowledge of the structures and organizations of their genes is still limited. In this study, a detailed structure and organization of the human intracellular LC-PTP (also called HePTP) gene is reported. The 13 to 18.5 kb genomic clones encoding human LC-PTP have been isolated. The LC-PTP gene is organized into 11 exons, including the 5'-noncoding first exon and the 3'-noncoding exon. Splicing sites for exons 4 to 10, which encode the conserved catalytic PTP domain, arise almost at the same position as for the CD45 gene. This elucidation of the LC-PTP gene structure provides insight into the domain evolution of intracellular LC-PTP and transmembrane CD45, which may be generated by gene duplications of an ancestral gene.

Protein kinase Calpha promotes apoptotic cell death in gastric cancer cells depending upon loss of anchorage.

Disruption of interactions between epithelial cells and extracellular matrix proteins leads to apoptosis of the cells, a phenomenon termed anoikis. Anoikis seems to play important roles in control of cellular positioning and inhibition of inappropriate cell growth. Here we found that a protein kinase C (PKC) activator phorbol ester 12-O-tetradecanoyl phorbol-13-acetate (TPA) promoted cell death in human gastric cancer cell lines MKN45 and MKN74 only when they lost anchorage. Loss of anchorage slightly increased enzymatic activity of PKCalpha, and an addition of TPA promoted cell death with further increase of PKCalpha activity, but not PKCbeta in MKN45 cells, implicating an involvement of PKCalpha in anoikis. Furthermore, vaccinia virus-mediated overexpression of PKCalpha strongly increased CPP32 activity in the detached MKN45 and MKN74 cells, and augmented anoikis, however it had little effect on viability and CPP32 activity in the attached cells. Taken together, PKCalpha promotes apoptotic cell death in gastric cancer cells depending upon loss of anchorage, thereby may be a modulator of anoikis.

Suppression of invasive properties of colon cancer cells by a metastasis suppressor KAI1 gene.

KAI1 is a potential metastatic suppressor gene for prostate cancer. We found by Northern blot analysis that six of ten (60%) gastric and colon cancer cell lines exhibited undetectable or very low expression level of KAI1 mRNA. The effects of KAI1 on the adhesion, motility and invasiveness of colon cancer cells was therefore investigated by using two kinds of stable transfectants, i.e., antisense transfectants of BM314 cells whose KAI1 mRNA expression was suppressed by transfer of antisense KAI1 cDNA and sense transfectants of DLD-1 cells with the enhanced KAI1 mRNA by sense cDNA transfer. The following results were obtained: (1) KAI1 gene expression had no significant effect on in vitro cell growth rate of colon cancer BM314 and DLD-1 cells; (2) Cell aggregation assay showed that KAI1 enhanced the Ca++-independent aggregatability of those colon cancer cells; (3) It was revealed by cell motility and invasion assays that KAI1 suppressed both the motility and in vitro invasiveness of those cells and (4) Furthermore, both the binding to fibronectin and the migration on fibronectin-coated plates of those cells were inhibited by KAI1 expression. These suggest that reduced KAI1 gene expression may contribute to the invasiveness and metastatic ability of colon cancer cells.