Biomedical subjects

Naoki Watanabe

Publications and source records attributed to Naoki Watanabe.

83 records · Page 5Linked to original sources

PubMedDate not supplied

Down-regulation of TRF1, TRF2 and TIN2 genes is important to maintain telomeric DNA for gastric cancers.

BACKGROUND: The maintenance of telomeres may be required for long-term proliferation of tumors. Activity of telomerase, a ribonucleoprotein complex that elongates telomeres, has been found in almost all human tumors but not in adjacent normal cells. Several factors which regulate telomere length, TRF1 and 2, TIN2, tankyrase and Rap1, have been identified. TRF1, TRF2 and TIN2 are negative regulators of telomere length, while tankyrase and Rap1 act as positive regulators. In this study, we quantitated the mRNA of these five genes in gastric cancers to clarify the mechanism by which cancer cells maintain telomere length. MATERIALS AND METHODS: The expression of these five genes transcription was determined using a quantitative RT-PCR. RESULTS: TRF1, TRF2 and TIN2 mRNAs were significantly down-regulated in cancers compared to non-cancerous mucosa. Neither tankyrase nor Rap1 was upregulated in cancers. CONCLUSION: Down-regulation of TRF1, TRF2 and TIN2 gene expression may be important to maintain telomeres in gastric cancer.

DNA, Neoplasm↗

PubMedDate not supplied

Overexpression of early growth response-1 as a metastasis-regulatory factor in gastric cancer.

BACKGROUND: To investigate the potential role of a nuclear transcription factor, early growth response-1 (Egr-1), in formation and progression of gastric cancer, we compared its expression in gastric cancers with that in non-cancerous tissues. MATERIALS AND METHODS: Egr-1 mRNA expression was measured using TaqMan RT-PCR. The corresponding protein expression was examined immunohistochemically. RESULTS: Egr-1 mRNA expression was significantly higher in gastric cancer tissues than in normal mucosa (p < 0.0005). These differences were also reflected by protein product expression. Moreover, Egr-1 mRNA expression was higher in cases with metastasis to lymph nodes or remote organs. In cultured gastric cancer cells known to have a high metastatic potential, expression of this mRNA was higher than that of parental cells. CONCLUSION: It was suggested that Egr-1 has a significant role in carcinogenesis and in cancer progression, especially metastasis. Measurement of this mRNA should be useful for evaluation of the metastatic potential of gastric cancer.

Breast↗

PubMedDate not supplied

Endogenous tumor necrosis factor promotes resistance to cellular stresses by inducing the metallothionein-1A gene.

BACKGROUND: Endogenous tumor necrosis factor (enTNF) acts as a resistance factor against anticancer drugs, heat and exogenous TNF via induction of manganous superoxide dismutase (MnSOD) and heat shock protein 72 (HSP72), while the details of interaction with other molecules are not fully understood. We compared mRNA expression of various genes between MIAPaCa-2 human pancreatic cancer cells and M5 cells transduced with nonsecretory-type TNF gene expression vector. MATERIALS AND METHODS: The expression of certain mRNAs between human pancreatic cancer MIAPaCa-2 cells and M5 cells was compared using fluorescent differential display. RESULTS: Of 140 bands obtained by gel electrophoresis, 53 bands showed patterns differing between MIAPaCa-2 and M5 cells. Among these bands, sequence analysis and RT-PCR identified strong mRNA expression for metallothionein-1A, a scavenger of reactive oxygen species, in transduced M5 cells. CONCLUSION: Metallothionein-1A could be induced by enTNF, resulting in resistance against various cellular stresses.

Base Sequence↗

PubMedDate not supplied

Enhanced expression of the UROC28 gene in human breast cancer: relationship to ERBB2 gene expression.

BACKGROUND: ERBB2, a highly important oncogene in invasive breast cancer, is not only a prognostic factor but also a predictive marker for response to therapeutic agents. Recently, An et al. (10) identified a novel gene, UROC28, that is also overexpressed in breast cancer. To examine possible interrelationships, we quantitated UROC28 and ERBB2 mRNA in breast cancers. MATERIALS AND METHODS: The expression of UROC28 and ERBB2 mRNA in breast cancer tissues were determined using RT-PCR. The expression was also examined in T-47D breast cancer cells treated with estrogen. RESULTS: UROC28 mRNA expression was greater in cancers than in noncancerous tissues (p < 0.0001), as was ERBB2 mRNA. ERBB2 and UROC28 gene expression was dose-dependently down-regulated in T-47D breast cancer cells treated with estradiol. However UROC28 mRNA and ERBB2 mRNA expression did not correlate with one another. CONCLUSION: These results indicate that UROC28 may be a useful target molecule in breast cancer diagnosis and treatment, complementing ERBB2.

Breast Neoplasms↗

PubMedDate not supplied

A proapoptotic caspase recruitment domain protein gene, TMS1, is hypermethylated in human breast and gastric cancers.

BACKGROUND: Conway et al. demonstrated that methylation of the proapoptotic gene, TMS1, was observed in breast cancer cell lines and tissues, resulting in decreased TMS1 gene transcription. However, whether the TMS1 gene is hypermethylated in other cancers is uncertain. MATERIALS AND METHODS: The expression of TMS1 mRNA was determined by quantitative RT-PCR. Methylation of the TMS1 gene was detected using methylation-specific PCR followed by bisulfite-modification of DNA. RESULTS: Methylation of the TMS1 gene was observed in breast, gastric and colorectal cancer cells. Down-regulation of TMS1 gene transcription in colorectal cancer cells was restored by treatment with a demethylating agent. Methylation of the TMS1 gene was observed in 2 out of 19 breast cancer specimens and 1 out of 9 gastric cancers, but in none of 13 colorectal cancers. CONCLUSION: These results suggest a direct role for aberrant methylation of the TMS1 gene in the progression of breast and gastric cancer involving down-regulation of the proapoptotic TMS1 gene.

Adenocarcinoma↗

PubMedDate not supplied

Selection of an internal control gene for quantitation of mRNA in colonic tissues.

BACKGROUND: GAPDH, beta-actin and 18S rRNA are widely employed as internal control genes, with the assumption that they are expressed constitutively to similar degrees in different cells and tissues and under different experimental conditions. In this study, we tested this assumption by assessment of the transcription of these three genes in human colonic tissues using a quantitative RT-PCR. RESULTS: GAPDH transcription was significantly greater in both colonic adenomas and cancers than in normal mucosa. In addition, transcription of beta-actin was significantly increased in cancers. The expression of 18S rRNA was essentially constant among these various tissues. Stable expression of 18S rRNA was observed during the growth of colonic cancer cells stimulated with serum, but both GAPDH and beta-actin transcription were up-regulated, coinciding with cell proliferation. CONCLUSION: These results indicate that 18S rRNA is more reliable than GAPDH and beta-actin as an internal control gene for quantitative comparison of mRNA in colonic cancers.

Actins↗

PubMedDate not supplied

A novel gene containing PDZ and LIM domains, PCD1, is overexpressed in human colorectal cancer.

BACKGROUND: The process of colorectal cancer development involves accumulated genetic alterations affecting APC, K-ras and p53. A recently identified gene, PCD1, was reported to be up-regulated in human malignancies including colorectal cancers, but relationships between PCD1 gene expression and clinicopathological findings, as well as the timing of genetic alteration of PCD1 in colorectal cancer development, are not clear. To determine whether PCD1 contributes to colorectal cancer progression, we investigated the expression of PCD1 mRNA in human colorectal tissues. MATERIALS AND METHODS: The expression of PCD1 mRNA was determined by quantitative RT-PCR. The mutation of p53 was detected by a PCR-SSCP method. RESULTS: Up-regulation of PCD1 gene transcription was observed not in adenomas but in cancers compared to normal mucosa (p < 0.0001). Primary tumors with a mutation of p53 showed significantly greater PCD1 gene expression than tumors without such a mutation (p = 0.0134). CONCLUSION: The PCD1 gene may play a role in colorectal cancer development from adenomas.

Adenocarcinoma↗

PubMedDate not supplied

PCD1, a novel gene containing PDZ and LIM domains, is overexpressed in human breast cancer and linked to lymph node metastasis.

BACKGROUND: Despite surgical removal of the primary tumor of breast cancer in patients with apparently localized disease, relapse at local or distant sites may occur because undetectable micrometastases were present at the time of diagnosis. Identification of molecules associated with breast cancer metastasis suggests possible new treatments. PCD1, a gene encoding a new member of the PDZ and LIM domain-containing protein family, recently was identified. We examined the relationships between PCD1 mRNA expression in breast cancers and metastasis. MATERIALS AND METHODS: PCD1 mRNA expression in breast cancer tissues was examined using a quantitative reverse transcription polymerase chain reaction. RESULTS: PCD1 mRNA expression was greater in cancers than in noncancerous tissues (p < 0.0001). In addition, high PCD1 gene expression was more frequent in patients with lymph node metastasis. CONCLUSION: PCD1 appears to contribute to breast cancer progression and nodal metastasis, thus representing a potential target molecule in breast cancer diagnosis and treatment.

Breast Neoplasms↗

PubMedDate not supplied

The effects of epirubicin hydrochloride (EPI) plus pretreatment of medroxyprogesterone acetate (MPA) on FM3A breast cancer cells transplanted in female C3H/He mice.

BACKGROUND: Little is known about how breast cancer cells are affected by the different regimens of medroxyprogesterone acetate (MPA) hormone therapy in combination with epirubicin (EPI). MATERIALS AND METHODS: The effectiveness of EPI with and without MPA pretreatment was compared when used on FM3A mouse breast cancer (FM3A) cells transplanted in female C3H/He mice. The effects of these regimens on angiogenesis induced by FM3A tumor were evaluated. RESULTS: A significant enhancement of the effects of EPI on the growth of FM3A cells by continuous MPA treatment was observed. The continuous treatment of MPA with EPI was most effective in the inhibition of angiogenesis in the tumors in all regimens tested. CONCLUSION: The combination of MPA pretreatment with EPI may be more effective than the simultaneous treatment of MPA with EPI for breast cancer. In addition, the results suggest that the anti-angiogenic effects of MPA combined with EPI on FM3A cells are parallel with the anti-tumor effects.

Angiogenesis Inhibitors↗

PubMedDate not supplied

Introduction of a survivin gene-specific small inhibitory RNA inhibits growth of pancreatic cancer cells.

BACKGROUND: The anti-apoptotic molecule survivin is expressed in human cancers of various origins. Since this molecule possesses multiple functions, including apoptosis inhibition, cell cycle promotion and enhancement of Fas ligand expression, survivin has attracted growing attention as a target in cancer treatment. A survivin-specific small inhibitory RNA (siRNA) was introduced into pancreatic cancer cells to investigate its effect on cancer cell growth. MATERIALS AND METHODS: Survivin mRNA and protein expression were examined by RT-PCR and Western blotting, respectively. DNA histogram analysis was performed using a flow cytometer. RESULTS: The introduction of survivin-specific siRNA reduced survivin mRNA and protein expression in PANC-1 cells by over 90% and to an undetected amount, respectively, and induced growth inhibition. The siRNA transfectants showed pronounced morphological changes including enlargement of cells and multinucleation. siRNA transfectants did not show cell cycle arrest, but underwent apoptosis. CONCLUSION: Our data suggest that the use of survivin-specific siRNA deserves further investigation as a novel approach to cancer therapy.

Cell Growth Processes↗

PubMedDate not supplied

Diagnostic relevance of overexpressed NOK mRNA in breast cancer.

A novel oncogene with a kinase domain (NOK), a receptor protein tyrosine kinase, has been reported to cause proliferation of normal cells, suggesting its possible use as a diagnostic marker in human cancer. To determine the significance of NOK expression in cancer cells, the effect of NOK inhibition was first examined on cell proliferation in vitro. The degree of expression in 52 clinical breast cancer samples was then correlated with clinical features. The transduction of NOK small inhibitory (si) RNA in T47D breast cancer cells decreased NOK mRNA expression, thereby inhibiting growth. When the mean expression in non-cancerous tissues from the same breast resection specimens +/-2SD was used as a cut-off value, 67.3% of breast cancers were positive for NOK expression - a higher positivity rate than that found for c-erbB2 (28.8%). NOK mRNA expression did not correlate with c-erbB2 expression, indicating the independence of NOK as a diagnostic marker. Furthermore, NOK mRNA was highly expressed even at early clinical stages. NOK mRNA might be an ideal target to support the diagnosis of breast cancer especially in tiny tumors in which the malignancy cannot be confirmed by other means.

Breast Neoplasms↗