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Biomedical subjects

K K Tanabe

Publications and source records attributed to K K Tanabe.

54 records · Page 3Linked to original sources
PubMed1996

Glutamine as a regulator of DNA and protein biosynthesis in human solid tumor cell lines.

OBJECTIVE: The transport of glutamine by six different human solid tumor-derived cell lines (e.g., breast, colon, liver) was characterized and the impact of glutamine deprivation on rates of tumor cell proliferation and DNA and protein synthesis was assayed. SUMMARY BACKGROUND DATA: Glutamine is added routinely to cell culture media and its importance for cellular growth has been established. However, carrier-mediated glutamine transport by solid tumors has not been studied extensively, and the mechanisms by which glutamine contributes to cell growth regulation require further investigation. METHODS: In a panel of different human solid tumor-derived cells, sodium-dependent glutamine transport was characterized in vitro and rates of cell proliferation, protein and DNA synthesis, as well as thymidine transport, were correlated with glutamine concentrations in the culture media. RESULTS: In all cells, regardless of tissue origin, sodium-dependent glutamine transport was mediated almost exclusively by a single carrier. There was a range of Michaelis constants (Km) and maximal transport velocities (Vmax) for the glutamine transporter in each cell type, but the amino acid inhibition profiles were nearly identical, consistent with uptake by the System ASC family of transporters. Rates of cell growth, DNA and protein synthesis, and thymidine transport correlated with the glutamine concentration in the culture media, indicating the central role of this amino acid in regulating cellular proliferation. CONCLUSIONS: These data indicate that glutamine transport by all solid tumors is mediated by the System ASC family of transporters. The variation in Km values suggests that some cancers may be better suited to survive in a low glutamine environment than others. The mechanism by which glutamine supports cell proliferation and regulates cell cycle kinetics involves its modulation of DNA and protein biosynthetic rates.

Cell Division↗
PubMed1996

Enhancement of gene therapy specificity for diffuse colon carcinoma liver metastases with recombinant herpes simplex virus.

OBJECTIVE: The authors determined whether a recombinant herpes simplex virus (HSV) vector could destroy human colon carcinoma cells in vitro and whether the vector would selectively replicate in colon carcinoma liver metastases but not surrounding hepatocytes in vivo. BACKGROUND: The HSV vector hrR3 is defective in the gene encoding ribonucleotide reductase and contains the lacZ reporter gene. Ribonucleotide reductase is expressed in actively dividing cells and generates deoxyribonucleotides for DNA synthesis. hrR3 replicates only in actively dividing cells that can provide ribonucleotide reductase in complementation, but not in quiescent cells such as normal hepatocytes. METHODS: hrR3-mediated lysis of HT29 human colon carcinoma cells was first determined in vitro. For in vivo studies, athymic BALB/c nude mice underwent intrasplenic injection of HT29 and intrasplenic injection of hrR3 7 days later, and were killed 7 days after viral injection. Their livers were examined histochemically for lacZ expression. RESULTS: All the HT29 cells were destroyed in vitro when hrR3 was added at a titer of 1 plaque-forming unit per 10 tumor cells. One hundred one of 105 tumor nodules examined in liver sections from mice treated by intrasplenic injection of hrR3 demonstrated lacZ expression. Minimal beta-galactosidase activity was present in normal liver. CONCLUSIONS: The hrR3 HSV vector effectively destroys HT29 human colon carcinoma cells at very low multiplicities of infection. Differential expression of ribonucleotide reductase between liver metastases and normal liver allows hrR3 to selectively replicate in tumor cells with minimal replication in surrounding normal liver. Further investigation of HSV-based vectors as oncolytic agents for liver metastases is warranted.

Animals↗
PubMed1995

CD44 hyaluronate binding influences growth kinetics and tumorigenicity of human colon carcinomas.

CD44 is a cell surface receptor of hyaluronate that is implicated in the regulation of tumor growth and metastatic potential. Transformation of colon mucosa to carcinoma is associated with overexpression of several CD44 alternative splice variants. The functional roles of CD44 isoforms in colon carcinoma tumor progression remain unclear. CD44H expression is downregulated in colon carcinomas compared to paired normal mucosa. In the present study we demonstrate that reintroduction of CD44H back into colon carcinoma cells by stable transfection reduces their in vitro growth rate and tumorigenicity. Examination of several colon carcinoma cell lines and use of mutant CD44H reveal that this in vitro and in vivo growth reduction requires the ability of CD44H to bind hyaluronate. These observations indicate that the CD44H downregulation associated with transformation of mucosa to colon carcinoma may provide the carcinoma cells with a growth advantage. Furthermore, the reduction in tumor growth rate mediated by reintroduction of CD44H into colon carcinoma cells is dependent on its ability to bind hyaluronate.

Animals↗
PubMed1995

Minimal-access surgery for staging of malignant melanoma.

OBJECTIVE: To develop a simple, minimally invasive technique of determining whether regional node metastasis has occurred in patients with melanoma. SETTING: Teaching hospital tertiary care and private practice settings. PATIENTS: Between February 1993 and October 1994, 121 patients with invasive malignant melanoma and clinically negative lymph nodes were enrolled in this clinical trial. DESIGN: Consecutive sample clinical trial. Within 24 hours prior to lymph node resection, a radioactive tracer was injected into the dermis around the site of the primary melanoma. Forty-four patients also had blue dye injected immediately prior to surgical resection. Measurement of radioactivity in the lymph nodes and surgical localization were made using a handheld gamma detector. Radiolabeled nodes were selectively removed with the least dissection possible. In patients with pathologically positive radiolabeled nodes, regional lymphadenectomy was performed. OUTCOME MEASURES: Successful identification of radiolabeled sentinel lymph nodes, correlation of radiolabeling with injection of blue dye, and regional node recurrence rate. RESULTS: Surgeons successfully resected the radiolabeled sentinel lymph nodes in 118 (98%) of 121 patients. One hundred percent of blue-stained lymph nodes were successfully radiolabeled. Fifteen patients had pathologically positive sentinel lymph nodes. In 10 patients, the sentinel node was the only node with metastasis. Two systemic and one regional node recurrences occurred during a mean follow-up of 220 days. CONCLUSIONS: Selective gamma probe-guided resection of the radiolabeled sentinel lymph node is possible in over 95% of patients with melanoma. This technique offers a simple and reliable method of staging of regional lymph nodes in these patients without performing a regional lymphadenectomy.

Adolescent↗
PubMed1995

Restoration of CD44H expression in colon carcinomas reduces tumorigenicity.

OBJECTIVE: The functional consequences of reintroduction of the CD44H cell adhesion molecule into colon carcinomas were investigated. BACKGROUND: CD44 is a cell surface adhesion molecule that is normally present in numerous isoforms as a result of messenger RNA alternative splicing. Individual CD44 isoforms differ in their ability to enhance tumorigenic or metastatic potential when overexpressed on tumor cells. Reverse transcriptase-polymerase chain reaction analysis demonstrates that CD44H is down-regulated during transformation of normal colon mucosa to carcinoma. The functional consequences of CD44H down-regulation in colon carcinomas has not been clarified. METHODS: Tumor cell lines and fresh tissue specimens were examined for CD44 expression by Western blot analysis. CD44H cDNA and site-directed mutants of CD44H cDNA were transfected into colon carcinoma cells. Stable transfectants were examined for adhesion to hyaluronate, in vitro growth, and in vivo growth. RESULTS: CD44H expression was nearly undetectable in primary colon carcinomas and colon carcinoma cell lines. In contrast, normal mucosa expressed high levels of CD44H. When CD44H was reintroduced into colon carcinoma cells, their in vitro and in vivo growth was significantly reduced. This CD44H-mediated growth rate reduction required an intact cytoplasmic domain. CONCLUSIONS: Transformation of normal mucosa to colon carcinoma is associated with a down-regulation of CD44H, which consequently may enhance the growth rate and tumorigenicity.

Blotting, Western↗
PubMed1995

Alternative RNA splicing of the hyaluronic acid receptor CD44 in the normal human brain and in brain tumors.

The cell-surface receptor for hyaluronic acid, CD44, is expressed by both normal and malignant cells. Numerous CD44 isoforms have recently been identified that are derived by alternative ribonucleic acid splicing. The expression of some CD44 isoforms has been shown to be involved in tumor progression and metastatic spread in a rat carcinoma model and in human carcinomas. In the present study, CD44 isoform expression was evaluated by reverse transcriptase-polymerase chain reaction (PCR) analysis in frozen sections derived from three samples of normal brain tissue and from 40 brain tumors, including samples of glioblastoma multiforme, anaplastic astrocytoma, low-grade astrocytoma, cerebral primitive neuroectodermal tumor, medulloblastoma, metastatic colon carcinoma, and metastatic melanoma. Normal brain tissue adjacent to the tumors was also examined in 14 of 18 glioblastomas. In all normal brain and tumor samples, with the exception of metastases from colon carcinoma, PCR analysis demonstrated one prominent product that corresponded to the CD44H hematopoietic form of CD44. Metastases from colon carcinoma demonstrated two prominent PCR amplification products corresponding to CD44H and CD44R1. These results suggest that CD44H is the predominant isoform of this protein in normal human brain tissue and in human neuroectodermal tumors of varying degrees of malignancy. The ability of CD44H to mediate tumor cell motility and invasiveness (in contrast to CD44R1) suggests that the CD44 alternative splicing pattern of neuroectoderm-derived tumors may enhance their local biological aggressiveness and intracerebral spread. The lack of expression of larger molecular weight CD44 variants by primary brain tumors may also partially explain why these tumors rarely metastasize to distant sites.

Alternative Splicing↗
PubMed1994

Influence of surgical margins on outcome in patients with preoperatively irradiated extremity soft tissue sarcomas.

BACKGROUND: Limb-sparing surgery for soft tissue sarcomas of the extremities may result in microscopically positive surgical margins. The consequences of these microscopically positive margins are unknown. We have analyzed the influence of surgical margins on local disease control and overall survival in patients with extremity soft tissue sarcomas who received preoperative radiation therapy followed by limb-sparing surgery. METHODS: Ninety-five consecutive patients with intermediate and high grade extremity sarcomas who received preoperative radiation therapy and limb-sparing surgery were identified from a soft tissue sarcoma data-base. The clinical outcome of 24 patients who had microscopically positive surgical margins was compared with that of 71 patients who had clear surgical margins. RESULTS: Multivariate statistical analysis revealed that patients with microscopically positive surgical margins or intraoperative tumor violation had an increased risk for local failure. High grade, large size, and intraoperative violation of the tumors were associated with decreased overall survival. However, neither the presence of a positive surgical margin nor the occurrence of a local failure adversely affected overall survival. CONCLUSIONS: Achieving negative surgical margins in patients with intermediate and high grade extremity sarcomas enhances local disease control but does not measurably improve overall survival. These data should be factored into patient management decisions in cases where the goal of achieving clear surgical margins requires amputation or the significant functional compromise of the extremity.

Actuarial Analysis↗
PubMed1994

The CD44 adhesion molecule and metastasis.

The family of related cell surface adhesion molecules designated CD44 are multifunctional proteins displayed by a wide variety of normal and malignant tissues. CD44 properties in vitro include hyaluronate-mediated adhesion, motility, hyaluronate degradation, self-aggregation, and adhesion to lymphoid tissue. These properties are among several that are required by invasive and metastatic tumor cells. Several in vivo experiments indicate that tumor cells transfected to overexpress specific CD44 isoforms display an enhancement in metastatic potential. Numerous CD44 isoforms exist as a result of alternative splicing, and specific isoforms enhance tumor cell metastasis more efficiently than others. This suggests that regulation of CD44 alternative splicing is an important determinant of metastatic potential. Several human tumors display specific alterations in CD44 isoform expression, and the extent of clinical disease in specific tumors correlates with the CD44 isoform expression pattern. In this review we analyze these data that suggest that CD44 plays an important role in tumor metastasis.

Animals↗
PubMed1993

Role and regulation of expression of 92-kDa type-IV collagenase (MMP-9) in 2 invasive squamous-cell-carcinoma cell lines of the oral cavity.

The present study was undertaken to determine the role of the metalloproteinase MMP-9 in the invasive phenotype of squamous-cell carcinoma of the oral cavity and the regulation of its expression. Zymographic analysis of conditioned medium from 2 highly invasive squamous-cell-carcinoma cell lines indicated large amounts of an enzyme which was indistinguishable, in size (92 kDa) from the MMP-9 pro-enzyme. Conversion of the 92-kDa gelatinase into a lower-molecular-weight species (84 kDa), identical in size to the activated gelatinase, was evident when both cell lines, which are avid secretors of urokinase, were cultured in the presence of plasminogen. Penetration of an extracellular-matrix-coated filter was dramatically reduced in the presence of the collagenase inhibitor, tissue inhibitor of metalloproteinase-2, suggesting a critical role for MMP-9 in the invasive process. Immunohistochemical studies demonstrating the presence of MMP-9 in tumor cells of resected squamous-cell cancers suggested that secretion of this collagenase by cells in vitro was reflective of the in vivo setting. Since several phorbol-ester response elements are present in the MMP-9 promoter, we determined the role of protein-kinase-C pathways in the regulation of MMP-9 expression in cultured SCC. Treatment of cells with PMA resulted in a more-than-20-fold increase in the level of protein and mRNA. Conversely, culturing of cells in the presence of the protein-kinase-C inhibitor, calphostin-C, led to a dose-dependent decrease in the amount of MMP-9 mRNA and protein, suggesting that the constitutive expression of this collagenase reflects activation of this signal transduction pathway. In summary, our data suggest that, for a sub-population of squamous-cell carcinomas, secreted MMP-9 is an important determinant of the invasive phenotype, and that the expression of this metalloproteinase is regulated by protein-kinase-C pathways.

Amino Acid Sequence↗
PubMed1993

Expression of CD44R1 adhesion molecule in colon carcinomas and metastases.

CD44 is a cell surface adhesion molecule postulated to control lymphocyte recirculation by facilitating entry into lymphoid tissue. Tumour cells transfected to overexpress the epithelial variant CD44R1 readily gain access to lymph nodes and distant metastatic sites in animal models, possibly by mimicking circulating lymphocytes. To investigate if human tumours display altered CD44 expression we performed reverse transcriptase a polymerase chain reaction (PCR) analysis of CD44 in 49 specimens from normal colonic mucosa, primary colon and rectal tumours, normal liver, and metastases of 20 patients. The haematopoietic variant CD44H was the principal isoform amplified in all of the specimens, However, 12/14 primary tumours and 16/16 metastatic potential. Moreover, the relative increase with only 2 of 13 normal mucosa specimens. This increase in CD44R1 relative to CD44H expressed by human colon carcinoma cells may increase their metastatic potential. Moreover, the relative increase in PCR amplification of CD44R1 compared with that of CD44H may provide a sensitive method for detecting primary and metastatic colon carcinoma cells in small biopsy specimens.

Base Sequence↗
PubMed1993

Novel variants of CD44 arising from alternative splicing: changes in the CD44 alternative splicing pattern of MCF-7 breast carcinoma cells treated with hyaluronidase.

CD44 is a cell-surface glycoprotein postulated to play a role in a variety of biological processes, including lymphocyte homing and tumor-cell metastasis. Several isoforms of CD44 have been identified in human cells, and the genesis of some of these isoforms has been attributed to alternative splicing. In the study presented here we amplified three novel transcript variants of CD44 from human cell lines using a reverse transcriptase-polymerase chain reaction strategy. Two of the novel isoforms differed from previously described CD44 isoforms as a result of alternative splicing that occurred at previously reported splice junctions. The third novel CD44 isoform was generated from a previously unreported alternative splice junction near the 5' end of the open reading frame. Southern blot analysis of genomic DNA revealed that these novel isoforms and all of the previously described CD44 isoforms arose from alternative splicing. The capability of cells to modify their CD44 alternative splicing pattern was demonstrated in MCF-7 cells, which altered their CD44-isoform expression pattern in response to treatment with hyaluronidase. A better understanding of mechanisms regulating CD44 alternative splicing may provide insights into diverse processes, including tumor-cell metastasis and lymphocyte homing.

Alternative Splicing↗
PubMed1989

Clostridial sepsis and malignant disease.

To address the significance of clostridial bacteremia in surgical patients, the bacteriologic records of the New York Hospital from an eight year period were reviewed. Of 1,708 patients who underwent surgical treatment with positive blood cultures, 23 (1.3 per cent) with clostridial bacteremia were identified. Twenty-one of the 23 patients manifested clinical signs of sepsis at the time of clostridial bacteremia consisting of fever, leukocytosis or hypotension. Fourteen patients had intra-abdominal sources of bacteremia and eight of these had either a diverticular abscess or colorectal perforation. The over-all mortality rate was 43 per cent, with all deaths resulting from uncontrolled sepsis. An association between clostridial bacteremias and malignant disease has been described. Thirteen malignant diseases were identified in 12 of the 23 patients reported herein. Carcinoma of the colon and rectum was the most frequently associated malignant condition, but a wide variety of other malignant diseases were also identified. The diagnosis of underlying malignant disease was known prior to the clostridial bacteremia in ten patients and unknown in two. None of the patients were receiving chemotherapy or radiation therapy at the time of bacteremia. Three different Clostridium species were isolated in patients with underlying malignant disease, supporting an association between malignant conditions and other Clostridium species as well as Clostridium septicum. The identification of clostridial bacteremia in surgical patients warrants both aggressive treatment of the septic state and a thorough search for associated malignant lesions.

Adolescent↗
PubMedDate not supplied

Multidisciplinary management of metastatic colorectal cancer.

When colorectal cancer metastasizes to distant organs, usually multiple sites are involved and treatment consists primarily of systemic chemotherapy and supportive care. Chemotherapeutic agents effective against metastatic colorectal cancer include 5-fluorouracil, often used in combination with leucovorin or methotrexate, and irinotecan (CPT-11). Median survival with optimal chemotherapy regimens ranges from 10 to 15 months. Less frequently, colorectal cancer metastasizes only to the liver or lung. In a minority of these cases, surgical resection can be performed and results in a median survival of 28-46 months for hepatic resections and 24-25 months for pulmonary resections. Five-year survival rates range from 24 to 38% and 21 to 44% for hepatic and pulmonary resections, respectively. For isolated liver metastases that are not surgically resectable, other regional therapies that can be considered are hepatic cryosurgery, radiofrequency ablation, and hepatic arterial infusion chemotherapy. Median survival following cryosurgery is between 26 and 30 months, while median survival following radiofrequency ablation has not been established in large series. Hepatic arterial infusion chemotherapy, especially with newer combination drug regimens, may increase survival in patients with isolated liver metastases compared to systemic chemotherapy, but this must be confirmed in randomized, prospective trials. Colorectal cancer metastases to the brain can be treated with radiation therapy or surgical resection, but median survival with treatment is less than one year.

Antineoplastic Agents↗
PubMedDate not supplied

Percutaneous radiofrequency tissue ablation: does perfusion-mediated tissue cooling limit coagulation necrosis?

PURPOSE: To determine, by decreasing hepatic perfusion during radiofrequency (RF) ablation, whether perfusion-mediated tissue cooling can explain the reduced coagulation observed in in vivo studies compared to that seen with RF application in ex vivo tissue. MATERIALS AND METHODS: RF was applied in vivo with use of cooled-tip electrodes to normal porcine liver without (n = 8) and with balloon occlusion of the portal vein (n = 8), celiac artery (n = 3), or hepatic artery (n = 2), and to ex vivo calf liver (n = 10). In vivo trials of vasopressin (0.3-0.6 U/min) infusion during RF application with (n = 10) and without (n = 2) arterial balloon occlusion were also performed. Intraoperative RF was subsequently performed in seven patients with hepatic colorectal metastases with and without portal inflow occlusion. Remote thermometry was performed in four patients. RESULTS: RF application (12 minutes) during portal venous occlusion produced larger areas of coagulation necrosis than RF with unaltered blood flow (2.9 cm +/- 0.1 vs 2.4 cm +/- 0.2 diameter; P < .01). With celiac and hepatic artery occlusion, coagulation diameter measured 2.7 cm +/- 0.2 and 2.5 cm +/- 0.1, respectively. Infusion of vasopressin without vascular occlusion reduced coagulation diameter to 1.1 cm. However, different methods of hepatic or celiac arterial balloon occlusion with simultaneous vasopressin infusion produced a mean 3.4 cm +/- 0.2 of necrosis. Coagulation in ex vivo liver was 2.9 cm +/- 0.1 in diameter. Clinical studies demonstrated greater coagulation diameter for metastases treated during portal inflow occlusion (4.0 cm +/- 1.3) than for tumors treated with normal blood flow (2.5 cm +/- 0.8; P < .05). Thermometry documented a 10 degrees C increase compared to baseline at 10 mm and 20 mm from the electrode after 5 minutes of portal inflow occlusion during constant RF application. CONCLUSIONS: Perfusion-mediated tissue cooling reduces coagulation necrosis achievable with RF ablation. Reduction of blood flow during RF application increases coagulation in both an animal model and human liver metastases.

Aged↗
PubMedDate not supplied

Influence of p53 on herpes simplex virus type 1 vectors for cancer gene therapy.

Herpes simplex virus type 1 (HSV 1) vectors are under investigation for use in gene therapy for colorectal cancer liver metastases. Approximately 60% of colorectal cancers possess p53 mutations, and p53 mutations can cause tumor cell resistance to radiation therapy and chemotherapy. p53 is also known to co-localize with at least one HSV 1 protein and influence HSV 1 gene expression. The purpose of this study was to determine if the loss or mutation of p53 in tumor cells alters the cytotoxicity of HSV 1 vectors. HSV 1 vector-mediated in vitro cytotoxicity assays were performed using stable transfectants of SAOS-2-LM2 cells and WiDr cells that express no p53, wild-type p53, mutant p53, or both wild-type p53 mutant p53. All stable transfectants were equally susceptible to HSV 1 vector cytotoxicity, and cell lines with mutant p53 were not resistant to HSV 1 vectors. These results provide additional rationale for the application of HSV 1 vector gene therapy for colorectal cancer.

Animals↗
PubMedDate not supplied

Adjuvant high-dose interferon alfa-2b in patients with high-risk melanoma.

We performed an analysis of toxicity and survival in stage III melanoma patients receiving adjuvant interferon alfa-2b (IFN). This was a retrospective single-arm analysis of 40 patients with stage III melanoma who received (IFN) administered at maximum tolerated doses of 20 mU/m2/day intravenously (i.v.) for 1 month and 10 mU/m2 three times per week subcutaneously (s.c.) for 48 weeks. Toxicity in our series is comparable to that experienced in the Eastern Cooperative Oncology Group (ECOG) 1684 trial, except for higher rates of dose-limiting myelosuppression and hepatotoxicity. All 40 patients experienced constitutional symptoms, but only 14/40 (35%) experienced grade 3 to 4 symptoms. Of the 40 patients, 36 (90%) experienced neurologic symptoms, but only seven (17.5%) experienced grade 3 to 4 neurotoxicity. Two patients stopped treatment because of severe psychiatric symptoms; one patient attempted suicide, and a psychosis developed in another. Thirty-nine (97.5%) patients experienced myelosuppression; 31 (77.5%) developing grade 3 to 4 myelosuppression. Hepatotoxicity was evident in 39 (97.5%) patients, and 26 (65%) experienced grade 3 to 4 hepatotoxicity. Three patients (7.5%) experienced mild renal toxicity. At a median follow-up of 27 months from initiation of therapy, there have been 19 relapses (47.5% disease-free survival [DFS]) and 10 deaths (75% OS) resulting from progression of disease. The DFS compares with the treatment arm in ECOG 1684 at 27 months, but overall survival is higher in our series of patients at the same time point. In a single program setting, IFN can be administered with similar side effects and outcome profiles seen in multi-institutional studies. Modifications in the induction regimen resulted in notably higher hematologic and hepatic toxicities but did not preclude administering further therapy and did not result in increased attrition rate among patients: only nine patients (22.5%) had their treatment stopped as a result of IFN-related toxicity. In comparison, 26% of patients had to have their treatment discontinued because of toxicity in ECOG 1684.

Adult↗