The role of Bcl6 in mature cardiac myocytes

OBJECTIVE

The Bcl6 gene encodes a sequence-specific transcriptional repressor and is ubiquitously expressed in adult murine tissues including heart muscle. The objective of this study was to examine the role of Bcl6 in cardiac myocytes.

METHOD

We developed Bcl6-deficient (Bcl6-/-) mice and histologically examined hearts from these mice.

RESULTS

Massive myocarditis with eosinophilic infiltration occurred in Bcl6-/- mice after 4-6 weeks of age. Since expression of the Bcl6 gene was induced in normal cardiac myocytes after 2 weeks of age and thereafter detected through adulthood, loss of Bcl6 in mature cardiac myocytes may be related to the induction of eosinophilic myocarditis. To examine the effects of eosinophils from Bcl6-/- mice on normal hearts, bone marrow cells from Bcl6-/- mice were adoptively transferred into sublethally irradiated RAG1-deficient mice. Although massive eosinophilic infiltration was detected in conjunctivas and spleens from the chimeric mice, myocarditis was never observed. Electron microscopic analysis of cardiac myocytes from Bcl6-/- mice revealed a spectrum of degenerative changes prior to eosinophilic infiltration.

CONCLUSION

Bcl6 maynot be essential for the maturation of cardiac myocytes but may play a role in protecting mature cardiac myocytes from eosinophilic inflammation.

Clinical significance of serum p53 antibody detection on chemosensitivity assay in human colorectal cancer

BACKGROUND AND OBJECTIVES

Alteration of the p53 gene product occurs frequently during progression of colorectal cancer. Recently, mutated p53 protein was found to induce the production of anti-p53 antibodies in the serum of patients. The purpose of this study was to evaluate the relationship between p53 status in serum and chemosensitivity in resectable colorectal cancer patients.

METHODS

A total of 22 patients with primary colorectal cancer who underwent surgical treatment were examined for chemosensitivity with iable tumor samples using the Histoculture Drug Response Assay (HDRA). Serum samples of these patients for p53 antibodies were obtained before tumor resection and assayed in duplicate using an enzyme-linked immunosorbent assay kit.

RESULTS

The inhibition index of 5-fluorouracil and cis-diamminedichloroplatinum (CDDP), determined by the HDRA method, in the seropositive group was significantly lower than that in the seronegative group (P < 0.01). Furthermore, significant statistical differences in chemosensitivity to 5-fluorouracil and CDDP were revealed depending on the presence of serum p53 antibodies.

CONCLUSIONS

Detection of serum p53 antibodies, which reflects p53 mutations in tumor tissue, is a simpler method which correlates with chemosensitivity and may contribute to the selection of favorable chemotherapeutic strategies for colorectal cancer.

The p53 gene mutation is of prognostic value in esophageal squamous cell carcinoma patients in unified stages of curability

BACKGROUND

The p53 gene alteration is identified in approximately half of all human tumors, and is now thought to be a key gene for regulating the cell cycle through the induction of p21(WAF1/CIP1) and inducing apoptosis through some genes such as BAX. In this study, we investigated the prognostic value of p53 mutation for postoperative esophageal squamous cell carcinoma patients.

METHODS

The subjects studied were 42 esophageal squamous cell carcinoma patients who underwent esophagectomy with complete curability in our department. The cases were limited to stage II and III. DNA was extracted from paraffin-embedded tissues. A p53 gene mutation was detected by polymerase chain reaction-single strand conformation polymorphism and subsequent direct sequencing method for exons 5 to 9. The 5-year survival rate was calculated and statistically compared between the p53 mutation(+) and (-) groups by the log rank test.

RESULTS

The p53 gene mutation was identified in 14 cases (33.3%). The 5-year survival rate of the p53 mutation(-) group (n = 28) was significantly higher than the (+) group (n = 14; 51.0% versus 35.7%, P <0.05 by the log rank test). Recurrence could be identified in 10 of 14 p53 mutation(+) cases (71.4%), whereas it was found in 12 of 28 (-) cases (42.8%).

CONCLUSION

The current study indicated that p53 mutation of tumor tissues might be a prognostic factor for esophageal squamous cell carcinoma cases and one of the risk factors for its recurrence.

Chromosome breakage and cell lethality in human hepatoma cells irradiated with X rays and carbon-ion beams

Prediction of radiosensitivity would be valuable for heavy-ion radiotherapy. Premature chromosome condensation (PCC) technique has been a potential predictive assay in photon radiotherapy, but has not been investigated for hepatomas receiving heavy ions. Two human hepatoma cell lines, i.e., HLE and HLF, were irradiated with either 290 MeV/u carbon ions or 200 kVp X rays. Cell lethality was assayed by colony formation and compared with the unrejoined fraction of chromatin breaks as measured by PCC technique. Carbon ions at linear energy transfer (LET) of 76 keV/micron produced cell death more effectively than those of 13 keV/micron and X rays. For the cell killing, the relative biological effectiveness (RBE) of 13 and 76 keV/micron carbon ions compared with X rays was 1.10-1.24 and 2.57-2.59, respectively. Mean number of chromosomes in HLE and HLF cells was similar to each other, i.e., 60.48 and 60.28. RBEs for chromatin breaks of 13 and 76 keV/micron carbon ions were 1.30-1.31 and 2.64-2.79, respectively. A strong correlation between unrejoined chromatin breaks and cell killing for human hepatoma cells was observed irrespective of radiation quality. We conclude that PCC provides a potential predictor for the radiosensitivity of individual hepatoma that are treated with photon as well as heavy ion irradiation.

Expression of wild-type p53 gene confers increased sensitivity to radiation and chemotherapeutic agents in human esophageal carcinoma cells

The status of the p53 gene of tumor cells can modify the sensitivity of the tumors to radiation and anti-cancer agents. Human esophageal cancer cells (T.Tn) bearing mutated p53 gene were retrovirally transduced with wild-type p53 gene. The transduced cells (T.Tn/p53) which stably expressed wild-type p53 proliferated at the same rate as parental cells. However, the sensitivity to radiation was significantly improved by the transduction and T.Tn/p53 cells became markedly susceptible to cisplatin and etoposide compared with parental cells. Administration of cisplatin noticeably suppressed the growth of T.Tn/p53 tumors but not T.Tn tumors inoculated in nude mice. Forced expression of wild-type p53 gene thereby can increase the sensitivity to DNA damage in esophageal cells.

Detection of preoperative serum anti-p53 antibodies in gastric cancer

The presence of circulating anti-p53 antibodies (p53Ab) was investigated in 81 gastric cancer patients by ELISA. Preoperatively, anti-p53Ab were revealed in 13 cases (16%), including 3 early gastric cancers. No significant correlation of p53Ab with patient age, sex, pathological parameters and tumor markers, such as CEA and CA19-9 was observed, although p53Ab positivity tended to be associated with a higher rate of lymph node metastases (p = 0.073). We have found no significant correlation between p53Ab and poor survival rate (p = 0.325). In conclusion, we have observed that p53Ab are detectable in gastric cancer patients, even at early stages of disease, however, p53Ab have not served as a predictor of poor prognosis in gastric cancer in this series.

Hepatic resection with and without surgical margins for hepatocellular carcinoma in patients with impaired liver function

BACKGROUND/AIMS

The significance of a surgical margin for hepatic resection of hepatocellular carcinoma (HCC) in patients with impaired liver function was evaluated.

METHODOLOGY

Sixty-eight patients, each with a solitary HCC, who had not received any prior treatments were divided into 2 groups, according to surgical margin: Group A included 25 patients who underwent resection with no margin (although the tumor was not exposed) and Group B included 43 patients with a sufficient surgical margin (mean distance: 9 mm). There were no significant differences in clinicopathologic variables between the 2 groups. The rate of stump recurrence, survival and recurrence-free survival were analyzed.

RESULTS

Among the 38 patients who had cancer recurrence after a median follow-up of 58 months, 9 (Group A, n=4; Group B, n=5) (24%) had recurrent lesions at the stump. The surgical margin was not a significant factor related to survival or recurrence, irrespective of cirrhosis, capsule formation, cancer spread, or tumor size.

CONCLUSIONS

Our results indicated that the HCC-free surgical margin is unlikely to be related to the survival of patients with impaired liver function unless the tumor is exposed on the raw liver surface.

Enhanced effects of monoclonal antibody carboplatin immunoconjugates uptake and anti-tumor effects with angiotensin II and tumor necrosis factor

The most important factor influencing the use of monoclonal antibody immunoconjugates for cancer treatment is effectiveness of enhancement for tumor targeting. We call attention to the vasoactive agents angiotensin II (ATII) for selective increase in tumor blood flow and cytokine tumor necrosis factor (TNF) to improve the vascular permeability of the tumor. Tumor localization and biodistribution were investigated by nude mice transplanted human colon adenocarcinoma (LS-180) with radiolabeled carboplatin immunoconjugates. Tumor activity 48 h after administration of ATII and TNF was significantly higher than in the control group. However, nonspecific accumulation in normal organs was not observed. In vivo anti-tumor effects in animals with ATII and TNF was significantly stronger than in those given the same dose drug alone or immunoconjugates alone. These results indicate that ATII and TNF could be useful tools for induction of stronger inhibition of tumor growth without systemic toxicity.

Frequent expression of midkine gene in esophageal cancer suggests a potential usage of its promoter for suicide gene therapy

We have examined the expression of midkine (MK), a neurotrophic factor with heparin-binding activity, in human esophageal cancer cells. Seven esophageal cell lines tested expressed the transcript and 8 out of 14 human esophageal tumor specimens were positively stained with anti-MK antibody, while surrounding normal esophageal tissues in these specimens were not stained. The 5'-flanking, 2.3 kb genomic region of the MK gene was shown to drive the transcription of a reporter gene in the esophageal cell lines in a cis acting manner. Forced expression in esophageal cancer cells of herpes simplex virus-thymidine kinase gene mediated by the flanking region of the MK gene conferred sensitivity to a prodrug, ganciclovir. The 5'-upstream region of the MK gene thus possesses putative promoter activity which can be used for suicide gene-based gene therapy for esophageal cancer.

Human papillomavirus types 16 and 39 in a vulval carcinoma occurring in a woman with Hailey-Hailey disease

A woman with Hailey-Hailey disease, suffering from carcinoma of the vulva, was examined by histology and for the presence of human papillomavirus (HPV) DNA by polymerase chain reaction (PCR) and in situ hybridization. Our diagnosis by histological examination revealed the vulval carcinoma to be a squamous cell carcinoma (SCC), adjacent to lesions of Hailey-Hailey disease and severe dysplasia/carcinoma in situ [vulval intraepithelial neoplasia (VIN) III]. The PCR with consensus primers for the L1 region (L1-PCR) successfully amplified HPV DNA using total DNA extracted from formalin-fixed and paraffin-embedded tissue specimens. Restriction fragment length polymorphism analysis and sequencing of L1-PCR products revealed HPV types 16 and 39. HPV 16-specific primers for the E6 region identified HPV 16 DNA. In situ hybridization analysis with biotinylated HPV 16 and 39 DNA probes revealed the presence of the HPV 39 genome in the nuclei of the tumour cells in the SCC. These results indicate that HPV 16 and 39 are associated with lesions in vulval carcinoma. Regarding the patient's susceptibility to infection in the case of Hailey-Hailey disease, there is a possibility that HPV was inoculated into the lesions of Hailey-Hailey disease and induced those of VIN III and SCC.

Combined therapy with radiofrequency thermal ablation and intra-arterial infusion chemotherapy for hepatic metastases from colorectal cancer

BACKGROUND/AIMS

In this preliminary study, we investigated the efficacy of combined radiofrequency thermal ablation therapy (RFA) with hepatic arterial infusion chemotherapy (HAI) in the treatment of multiple liver metastases from colorectal cancer.

METHODOLOGY

Nine patients with bilobular multiple metastases was treated. The number of nodules was 6.0 +/- 3.9 (range: 2-13), and the size was 2.1 +/- 1.0 cm (range: 0.5-4.8 cm) in diameter. RFA was performed using a RF generator operating at 460 kHz with a 15-gauge, 4-prong custom RF needle. Treatment temperature was kept at 90-110 degrees C for 5 min. 5-Fluorouracil (5-FU) was administered by weekly 750-1250 mg/body/5 h as the regimen of HAI.

RESULTS

During a 15.2-month follow-up period, 6 of 9 patients survived more than 1 year. Three of the 6 survived more than 2 years. Serum CEA level in 5 patients dropped from 24.5 +/- 9.5 ng/ml to 10.3 +/- 5.5 ng/ml. Local recurrence was observed in 5 patients and new lesions in 4. Extrahepatic recurrence was observed in 5 patients. There were no serious complications but one HAI-related cerebral thrombosis.

CONCLUSIONS

Combined RFA with HAI would be effective and safe. This modality provides a new option for the treatment of multiple liver metastases from colorectal cancer.

Importance of positive peritoneal lavage cytology findings in the stage grouping of gastric cancer

Although peritoneal lavage cytology is widely performed during surgery for gastric cancer and the results have been reported to be one of the accurate prognostic factors, the cancer stage is determined independent of the results of lavage cytology according to the First English Edition of Japanese Classification of Gastric Carcinoma. In this study we demonstrated the validity of lavage cytology for accurately staging gastric cancer. Between 1988 and 1996, peritoneal lavage cytology was performed in 347 patients with resectable gastric cancer. Among them, cytology was positive in 29 cases (8.4%). The survival rate of the cytology-positive patients in each stage was worse than that of all patients in the same stage. The prognosis of patients with positive cytology findings and serosa-exposed gastric cancer was significantly worse than that of negative cytology findings and serosa-exposed gastric cancer, and similar to that of negative cytology findings and serosa-infiltrating gastric cancer. Our data indicated that positive cytology findings thus indicated a poor prognosis, and the prognostic difference between positive and negative cytology findings was approximately a one-stage difference in the Japanese stage grouping. Based on our findings, the results of peritoneal lavage cytology should thus be included in the factors for staging gastric cancer.

Lymph node metastasis with adenocarcinoma of the gastric cardia: clinicopathological analysis and indication for D1 dissection

PURPOSE

To establish the indications for proximal resection with dissection of perigastric lymph nodes in order to treat adenocarcinoma of the gastric cardia.

METHODS

We analyzed the clinicopathological features of 110 resected adenocarcinomas of the gastric cardia with respect to the appropriate operative method and extent of lymphadenectomy for treatment.

RESULTS

Of the 110 patients, 93 underwent curative resection. The D2 group (total gastrectomy with dissection of extended regional lymph nodes) revealed higher morbidity and mortality rates compared to the D1 group (proximal resection with dissection of perigastric lymph nodes). The risk of lymph node metastasis was determined by depth of invasion, size of tumors, and gross findings of tumors.

CONCLUSION

The appropriate operative method for adenocarcinoma of the gastric cardia requires: (i) tumor size less than 4 cm; and (ii) gross findings indicating a superficial type of lesion, which are recommended for proximal resection with dissection of perigastric lymph nodes.

Antitumor response of genetically engineered IL-2 expression to human esophageal carcinoma cells in mature T cell-defective condition

We examined whether antitumor effect could be produced by retrovirally expressed human interleukin-2 (hIL-2) gene in human esophageal cancer cells (T.Tn) using immunocompromised nude mice. Loss of tumorigenicity of hIL-2-producing T.Tn (T.Tn/hIL-2) cells inoculated subcutaneously was observed in contrast to continuous tumor growth of wild-type cells, although in vitro proliferation of T.Tn/hIL-2 cells remained the same as that of wild-type cells. The antitumor effect was also evidenced by the injection of T.Tn/hIL-2 cells into established tumors of wild-type cells. The injection significantly retarded the subsequent growth of wild-type tumors. Histological examination of regressing T.Tn/hIL-2 cells revealed necrotic areas and infiltration of several types of inflammatory cells. Treatment of nude mice with anti-asialoGM1 antibody did not influence the IL-2-mediated tumor rejection. Vaccination of nude mice with irradiated T.Tn/hIL-2 cells whose secretion of hIL-2 in amount was comparable to that of unirradiated cells did not develop protective immunity. Taken together, the antitumor effect achieved in nude mice by the inoculation of T.Tn/hIL-2 cells is mediated by non-T non-natural killer cells.

Inhibition of peritoneal dissemination of murine colon carcinoma cells by administrating retrovirus harboring IL-2 gene

We have examined the antitumor effect of the retrovirally expressed interleukin-2 (IL-2) gene in murine colon carcinoma cells (Colon 26) on a disseminated model within the peritoneal cavity. Intraperitoneal injection of IL-2-producing Colon 26, but not wild-type cells, into syngeneic mice did not cause animal death and conferred T-cell-dependent, tumor-specific protective immunity on the inoculated mice. Direct administration of the retrovirus harboring IL-2 gene into the peritoneal cavity of the mice that had intraperitoneal tumor of wild-type cells significantly prolonged the survival of the mice compared with that of the mice that received control retrovirus. In the surviving mice treated with the retrovirus we also observed the induction of protective immunity with tumor specificity. Integrated retrovirus DNA was not detected in any organs examined. Thus, in vivo IL-2 gene transfer by retrovirus enabled tumor-bearing mice to generate antitumor immunity without unnecessary retroviral insertion into host genome.

Evaluation of a new staging system by the Japanese Research Society for Gastric Cancer

The feasibility of the new classification of stage grouping by the Japanese Research Society for Gastric Cancer was evaluated. During the 22-year period between January 1975 and December 1996, a total of 1294 patients with primary gastric cancer underwent laparotomy at the Department of Surgery, Chiba University; 1222 had their lesions removed during the gastrectomy and 72 remained nonresected. Cases of direct operative death totaled 17 (1.3%). Five hundred patients (38.6%) died of a relapse of the original cancer and 42 (3.2%) died of other diseases within the followup period. Six patients (0.5%) were lost during the followup. The 5-year cumulative patient survival rates of the seven stages of the new stage grouping were distinctly proportional, and the differences were also statistically significant except between stages IIIb and IVa. The two major revised points in the new stage grouping, new classification of the depth of cancer invasion, and new stage grouping by a mosaic combination of the degree of invasion and lymph node metastasis were thus found to be reasonable based on the actuarial 5-year survival rates of the subgroups in the same stage. The present study also showed that the classification of stage IV still requires further discussion.

Beneficial effects of renal transplantation on cardiovascular disorders in dialysis patients

The present study was conducted to evaluate the impact of successful renal transplantation against the cardiovascular risk factors of patients on maintenance dialysis in whom cardiovascular accidents are the most common cause of death. A total of 74 renal transplant patients with grafts that had been functioning well for longer than 6 months after transplantation were examined before and 6-250 months after transplantation. The mean age was 34 years and the duration after transplantation was 104 +/- 66 months. An improvement in anemia from hemoglobin level of 9.0 to 13.6 g/dl and a decrease in mean systolic blood pressure from 157 +/- 24 to 135 +/- 14 mm Hg (P < 0.001) were observed after transplantation. An elevation in RV5 + SV1 levels by 0.6 mV on electrocardiogram (P = 0.042) was seen without any change in the cardiothorathic ratio on chest X-ray. Echocardiographic measurements of six recipients revealed great improvements in the left ventricular systolic dimension and thickness of the posterior wall of the left ventricle. Moreover, the ejection fraction and fractional shortening rose significantly from 59.4% +/- 16.3% to 75% +/- 8.1%, and from 30.6% +/- 9.2% to 44.8% +/- 7.9% (P = 0.017), respectively. These findings clearly show that successful renal transplantation can significantly improve the cardiovascular function of renal patients on maintenance dialysis.

Detection of serum p53 antibodies in patients with esophageal squamous cell carcinoma: correlation with clinicopathologic features and tumor markers

The significance of serum p53-Abs in patients with esophageal squamous cell carcinoma was determined. Examination of clinicopathological features and assessment of tumor marker sensitivities of carcinoembryonic antigen (CEA), squamous cell carcinoma antigen (SCC-Ag) and CYFRA21-1 were performed. Thirty-three (58%) of 57 patients were positive for serum p53-Abs, however, no relation with cancer progression existed. Fourteen of the 33 sero-positive patients revealed normal levels of all tumor markers tested. Thus, serum p53-Abs appears to be a useful marker for the detection of esophageal squamous cell carcinoma.

Benign esophageal stricture caused by diffuse severe esophagitis presenting as ascending fibrosis: report of a case

A 46-year-old Japanese man was referred to our hospital for treatment of an esophageal stricture. Esophageal cancer was suspected after detailed investigations, and a right transthoracic esophagectomy was performed. The resected specimen showed only nonspecific esophagitis with severe fibrous thickening in the submucosa, but no evidence of malignancy. Between 1906 and 1993, only 19 similar cases of benign esophageal strictures with fibrous thickening, excluding congenital and iatrogenic strictures, have been reported in Japan. These lesions occurred in the middle to lower third of the esophagus in 15 of 19 cases (78.9%), and 8 of the 19 patients (42.1%) were aged between 30 and 50 years. The interval between onset and hospital admission was short, being less than 1 year in 8 of the 12 patients for whom this information was available. Our patient demonstrated a disorder resembling the diffuse severe esophagitis described by Roth in 1974.

Interactive mechanisms among pituitary adenylate cyclase-activating peptide, vasoactive intestinal peptide, and parathyroid hormone receptors in guinea pig cecal circular smooth muscle cells

Vasoactive intestinal peptide (VIP) causes relaxation of smooth muscle cells via both VIP-specific receptor coupled to nitric oxide synthase and VIP-preferring receptor coupled to adenylate cyclase. Because the mechanism of interaction among VIP, pituitary adenylate cyclase-activating peptide (PACAP), and PTH is still unclear, the characteristics of the receptors for PACAP and PTH in circular muscle cells obtained from the guinea pig cecum were investigated. The effects of an inhibitor of cAMP-dependent protein kinase [cyclic adenosine 3',5'-monophosphorothioate (Rp-cAMPS)], guanylate cyclase inhibitors, antagonists of these peptides, and the selective receptor protection on the relaxing effect produced by PACAP, VIP, and PTH were examined. PACAP-induced relaxation was significantly inhibited by a VIP antagonist, a PTH antagonist, Rp-cAMPS, and an inhibitor of particulate guanylate cyclase. VIP-induced relaxation was significantly inhibited by a PACAP antagonist and a PTH antagonist. PTH-induced relaxation was significantly inhibited by a VIP-specific receptor antagonist and Rp-cAMPS, but not by a PACAP antagonist. A PTH antagonist significantly inhibited a VIP-preferring receptor agonist-induced relaxation. The muscle cells in which cholecystokinin octapeptide and PTH receptors were protected completely abolished the inhibitory responses to VIP and PACAP. The muscle cells in which cholecystokinin octapeptide and VIP or PACAP receptors were protected completely abolished the inhibitory response to PTH. This study shows that PACAP induces relaxation of these muscle cells via both VIP-preferring receptor coupled to adenylate cyclase and PACAP-specific receptor, and that PTH induces relaxation of the muscle cells via PTH-specific receptor coupled to adenylate cyclase. In addition, the results of a selective receptor protection show that PTH does not bind to VIP receptors, and that VIP does not bind to PTH receptor. Therefore, this study first demonstrates the presence of one-way inhibitory mechanisms from the PTH-specific receptor to the VIP-preferring receptor, and from the VIP-specific receptor to the PTH-specific receptor in the mechanisms of interaction between VIP and PTH.