SIRT1 Promotes Chemoradiotherapy Resistance in Esophageal Squamous Cell Carcinoma.

INTRODUCTION: Identifying accurate biomarkers for predicting response to chemoradiotherapy (CRT) in patients with esophageal squamous cell carcinoma (ESCC) is a critical challenge. The protein SIRT1, recognized for its implications in longevity, has been associated with tumor promotion in ESCC. However, data regarding its correlation with CRT sensitivity remain unreported. Therefore, in this study, we aimed to investigate the relationship between SIRT1 expression and CRT sensitivity and concurrently assess the effect of SIRT1 knockdown on CRT sensitivity in ESCC. METHODS: This study included 73 patients who underwent radical esophagectomy after CRT. SIRT1 expression in pre-treatment endoscopic biopsies was assessed through immunostaining, followed by a comparative analysis of CRT effects on surgical specimens. Small interfering RNA was used to attenuate SIRT1 expression in TE5 and TE10 cells, which were then subjected to cisplatin treatment at varying doses and concentrations and irradiation with X-rays, respectively. RESULTS: High SIRT1 tissue expression was significantly associated with CRT resistance. Multivariate analysis identified high SIRT1 expression as an independent biomarker for poor CRT response. In TE-5 and TE-10 cells, SIRT1 knockdown significantly decreased cell viability and increased sensitivity to cisplatin and radiation treatment compared to that of the negative control. CONCLUSION: Our study results demonstrate the potential of SIRT1 as a predictive biomarker for CRT response in ESCC, highlighting the heightened sensitivity to CRT upon the transcriptional inactivation of SIRT1. Targeting SIRT1 emerges as a promising strategy for enhancing the efficacy of CRT for ESCC.

Hypoxia­regulated exosomal miR­185 inhibits esophageal squamous cell carcinoma progression and predicts prognosis.

Despite advances in treatment and diagnosis, the prognosis of patients with esophageal squamous cell carcinoma (ESCC) remains poor. MicroRNAs (miRNAs/miRs) are associated with prognosis in esophageal cancer, indicating that they may help guide treatment decisions. The aim of the present study was to explore exosomal miR-185 as a candidate prognostic biomarker and therapeutic target in ESCC, to investigate its biological function and clinical significance, and to ascertain the applicability of circulating exosomal miR-185 for the development of targeted drugs for ESCC treatment. A GeneChip miRNA array was used to compare exosomal miRNA expression in ESCC cell lines under hypoxia with those under normoxia. Exosomal miR-185 expression was then confirmed by reverse transcription-quantitative PCR. Patient background and prognosis were compared between high and low miR-185 expression groups. Functional analyses were performed to evaluate the antitumor effects of miR-185 in ESCC cells. Global Gene Set Enrichment Analysis of The Cancer Genome Atlas data was also performed, and differentially expressed exosomal miRNAs under hypoxia were identified compared to those under normoxia. Hypoxia markedly decreased the expression of exosomal miR-185 in KYSE-960 and T.Tn cell culture media. Overexpression of miR-185 suppressed the migration, invasion and colony-forming abilities of ESCC lines, and also suppressed cell cycle progression and promoted apoptosis after cisplatin treatment. Notably, high miR-185 expression was associated with signaling pathways related to cell death, DNA damage and p53. Furthermore, circulating exosomal miR-185 levels were associated with cN and cStage, and could predict progression-free survival and disease-specific survival of patients with ESCC after initial treatment. In conclusion, miR-185 holds potential as a prognostic biomarker and therapeutic target in ESCC.

Establishment of a novel small bowel adenocarcinoma cell line using patient­derived xenografts, which produces CEA and CA19­9.

Small bowel adenocarcinoma (SBA) is a rare tumor with a poor prognosis. Due to its rarity, the research infrastructure for SBA, including cell lines, is inadequate. The present study established a novel SBA cell line, SiCry-15X, using patient-derived xenografts of SBA. The following criteria were defined for establishment: Long-term culturability, tumorigenicity and similarity with the original tumor. The biological characteristics of the cell line, its sensitivity to anticancer drugs and its ability to produce tumor markers carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA19-9) were evaluated. SiCry-15X cells adhered and grew as a monolayer, with a population doubling time of 37 h. Polymerase chain reaction results confirmed the human origin of the cell line, and short tandem repeat analysis revealed that the cells were genetically identical to the original tumor. The 50% inhibitory concentrations of 5-fluorouracil, paclitaxel, irinotecan, oxaliplatin and cisplatin for SiCry-15X were 104.05, 0.24, 63.3, 146.55 and 49.29 µM, respectively. CEA and CA19-9 concentrations in the culture media were markedly elevated. In addition, CEA and CA19-9 levels in the serum of cell-derived xenograft model mice were elevated. Moreover, CEA and CA19-9 were produced by SiCry-15X cells and distributed throughout the blood. Furthermore, increases in serum CEA and CA19-9 of cell-derived xenograft model mice were consistent with the clinical course of the disease. The newly established SBA cell line, SiCry-15X, could be an effective tool for conducting further studies on SBA.

A case of laparoscopic revision surgery 30 years after vertical banded gastroplasty for morbid obesity.

As the number of bariatric and metabolic surgeries being performed is increasing, the importance of revision surgeries is escalating. In this report, we describe a case of revision surgery performed 30 years after vertical banded gastroplasty (VBG), including a review of the surgical techniques. The patient was a male in his 50s who had previously undergone VBG for morbid obesity (body mass index of 72.6 kg/m2 ), resulting in gradual weight loss. Twenty-eight years later, reflux symptoms due to stenosis of the mesh area developed. Despite conservative treatment, the symptoms recurred, and aspiration pneumonia developed. Gastrojejunal and Y-anastomoses were performed laparoscopically. Postoperatively, the patient progressed well with no weight regain. In revision surgery, it is essential to accurately assess the patient's pathophysiology, as the surgical technique must consider improvement in symptoms, risk of weight regain, and the need for observation of the residual stomach.

Gut microbiome can predict chemoradiotherapy efficacy in patients with esophageal squamous cell carcinoma.

PURPOSE: The gut microbiome plays an important role in cancer pathogenesis and therapy. Some studies have reported that specific bacteria in tumor tissues may contribute to the prognosis and treatment of esophageal squamous cell carcinoma (ESCC). However, there is limited evidence that the gut microbiome is associated with ESCC. This study assessed the utility of the gut microbiome as a predictive marker of the therapeutic effect in patients with ESCC undergoing chemo-radiotherapy (CRT). PATIENTS AND METHODS: Fecal samples were collected from 51 patients with ESCC who had never undergone treatment between April 2021 and May 2022 in the Department of Frontier Surgery, Chiba University. The gut microbiome was analyzed using 16S metagenomics sequencing. The association between the gut microbiome composition and stage according to the TNM classification (American Joint Committee on Cancer 7.0) and CRT response according to the RECIST criteria was evaluated. RESULTS: The relative abundance of Fusobacteriaceae was enriched in cStage III-IVb group. Among the 27 patients who received CRT, the relative abundance of Lactobacillaceae was enriched in those with a partial and complete response. Lactobacillaceae also did not correlate with any clinical data, but the high Lactobacillales group had a higher LMR (P = 0.032) and lower PLR (P = 0.045) than in the low Lactobacillales group. CONCLUSIONS: In conclusion, we found that the relative abundance of Lactobacillaceae was enriched in patients with a partial or complete response among CRT those with ESCC, thus suggesting that the relative abundance of Lactobacillaceae can predict the effect of CRT.

Soluble PD­L1 reflects cachexia status in patients with gastric cancer and is an independent prognostic marker for relapse­free survival after radical surgery.

Soluble programmed death-ligand 1 (sPD-L1) levels can be used as a biomarker for gastric cancer (GC). However, comprehensive information regarding the sPD-L1 expression profiles and their association with cachexia in GC is lacking. Therefore, the present study evaluated the association between clinicopathological findings and sPD-L1 levels in patients with GC. Serum samples were collected from patients with GC during their first visit to Department of Esophageal-Gastro-Intestinal Surgery, Chiba University Hospital, Chiba, Japan (January 2012-December 2017; n=173), and sPD-L1 levels were measured using an enzyme-linked immunosorbent assay. Survival rates among 116 patients, excluding cases with preoperative chemotherapy or no radical procedures, were analyzed. sPD-L1 levels were associated with factors such as neutrophil-to-lymphocyte ratio, hemoglobin (Hb) and albumin (Alb) levels, total cholesterol and C-reactive protein (CRP) levels, and related to inflammation and nutrition in patients. Notably, the higher the number of applicable indicators related to cachexia (Hb <12 g/dl, Alb <3.2 g/dl, CRP >0.5 mg/dl and low body mass index) was, the higher the sPD-L1 value was. However, the pathological stage did not significantly differ between the groups. Clinicopathologically, there was no association with tumor depth, lymph node metastasis or vascular invasion; however, patients with the intestinal type had significantly higher sPD-L1 levels than patients with the diffuse type (P=0.032; Wilcoxon test). The overall survival did not significantly differ between the groups with low and high sPD-L1 levels; however, among patients who received radical treatment, the relapse-free survival was significantly worse in the high-sPD-L1-level group than in the low-sPD-L1-level group (P=0.025; log-rank test). Multivariate Cox regression analysis revealed that a high sPD-L1 concentration was a sign of poor prognosis, independent of pathological stage and cancer antigen CA19-9 (P=0.0029). Therefore, the present findings suggest that sPD-L1 can reflect cachexia status in patients with GC and may serve as a prognostic marker for relapse-free survival after radical GC surgery.

Serum Versus Tissue SIRT1 as Potentially Valuable Biomarkers in Gastric Cancer.

BACKGROUND/AIM: We lack reports on the clinicopathological characteristics and prognostic value of serum sirtuin 1 (SIRT1) levels and their association with SIRT1 expression in tissues of patients with gastric cancer (GC). Thus, we investigated the pathological characteristics and prognostic values of SIRT1 tissue expression and its serum concentration in GC. Moreover, we investigated the correlation between these two factors. MATERIALS AND METHODS: A total of 78 patients with GC who underwent curative gastrectomy were evaluated in this study. The expression of SIRT1 in the surgical specimens was assessed using immunohistochemistry. Serum levels of SIRT1 were measured using an enzyme-linked immunosorbent assay. The association of tissue and serum SIRT1 with the clinicopathological features and prognosis were evaluated. RESULTS: Positive SIRT1 tissue expression was significantly related to an advanced cancer stage (p=0.017). Furthermore, a significant relationship existed between a positive SIRT1 tissue expression and poorer overall survival (OS) and relapse-free survival (RFS) (p=0.033 and p=0.033, respectively). In contrast, serum SIRT1 levels showed no significant association with clinicopathological characteristics besides age. In addition, no significant correlation was observed between tissue SIRT1 expression and serum SIRT1 concentration. CONCLUSION: Tissue SIRT1 expression may be a valuable novel prognostic biomarker; nonetheless, further studies are required to clarify the relationship between tissue SIRT1 expression and serum SIRT1 levels in GC.

Standard versus low-dose nab-paclitaxel in previously treated patients with advanced non-small cell lung cancer: A randomized phase II trial (JMTO LC14-01).

BACKGROUND: Nab-paclitaxel (nab-PTX) has better transfer to tumor tissue than cremophor-based paclitaxel. It suggests that the optimum dose of nab-PTX might be lower than the dose and schedule that is widely used. We designed a randomized phase II trial to examine the clinical utility and safety of nab-PTX in patients with previously treated advanced non-small cell lung cancer (NSCLC). METHODS: Patients were randomly allocated (1:1) to receive nab-PTX monotherapy at 100 mg/m2 (group A) or 70 mg/m2 (group B). The primary endpoint was progression-free survival (PFS). Secondary endpoints included overall survival (OS), objective response rate (ORR), and adverse events (AEs). RESULTS: Finally, 81 patients were randomized. Similar results were observed in both groups for PFS (3.75 vs. 3.71 months), OS (13.50 vs. 16.13 months), or ORR (20.5% vs. 23.1%). The incidences of grade 3 or worse AEs were 57.5% in group A and 41.5% in group B. The proportion of serious side effects was 10.0% in group A and 4.9% in group B. CONCLUSION: Both standard dose and low dose of nab-PTX monotherapy are active for previously treated NSCLC patients with better safety profile. Therefore, nab-PTX 70 mg/m2 dose and schedule in the trial would be a reasonable option.

Transition from epoprostenol to selexipag in a patient with systemic sclerosis and pulmonary hypertension during the postoperative period of colon cancer surgery: A case report.

Introduction: Most pulmonary vasodilators are administered orally; however, in patients with pulmonary hypertension undergoing gastrointestinal surgery, a switch to parenteral drugs is needed. Parenteral pulmonary vasodilators carry a risk of infection and reduced quality of life owing to long-term central venous catheterization; therefore, it is preferable to switch them to oral vasodilators after surgery. Here, we present the case of a patient with systemic sclerosis complicated by pulmonary hypertension and colon cancer, for which treatment was successfully switched from epoprostenol to selexipag postoperatively. Case Description: A 59-year-old woman, who was diagnosed with mixed group I and III pulmonary hypertension and systemic sclerosis, was on oral triple pulmonary vasodilators for pulmonary hypertension and Raynaud's phenomenon. She was diagnosed as having colon cancer 3 months before admission. Despite the severe pulmonary condition and treatment with oral triple pulmonary vasodilators, colon cancer resection surgery was performed with the management for pulmonary hypertension through multidisciplinary treatments in collaboration with cardiology specialists. Medications for patients with pulmonary hypertension undergoing gastrointestinal surgery need to be switched from oral vasodilators to epoprostenol perioperatively. On postoperative day 19, 0.4 mg/day of selexipag was administered with epoprostenol. Subsequently, the epoprostenol dosage was gradually decreased, and selexipag was increased. On postoperative day 30, the dose of selexipag was increased to 1.2 mg/day and epoprostenol was discontinued. The patient was discharged on postoperative day 40. Conclusion: In our case, transition from epoprostenol to selexipag contributed to a more useful management strategy for systemic sclerosis and pulmonary hypertension in the postoperative period.

Clinical characterization of patients with primary aldosteronism plus subclinical Cushing's syndrome.

BACKGROUND: Primary aldosteronism (PA) plus subclinical Cushing's syndrome (SCS), PASCS, has occasionally been reported. We aimed to clinically characterize patients with PASCS who are poorly profiled. METHODS: A population-based, retrospective, single-center, observational study was conducted in 71 patients (age, 58.2 ± 11.2 years; 24 males and 47 females) who developed PA (n = 45), SCS (n = 12), or PASCS (n = 14). The main outcome measures were the proportion of patients with diabetes mellitus (DM), serum potassium concentration, and maximum tumor diameter (MTD) on the computed tomography (CT) scans. RESULTS: The proportion of DM patients was significantly greater in the PASCS group than in the PA group (50.0% vs. 13.9%, p <  0.05), without a significant difference between the PASCS and SCS groups. Serum potassium concentration was significantly lower in the PASCS group than in the SCS group (3.2 ± 0.8 mEq/L vs. 4.0 ± 0.5 mEq/L; p <  0.01), without a significant difference between the PASCS and PA groups. Among the 3 study groups of patients who had a unilateral adrenal tumor, MTD was significantly greater in the PASCS group than in the PA group (2.7 ± 0.1 cm vs. 1.4 ± 0.1 cm; p <  0.001), without a significant difference between the PASCS and SCS groups. CONCLUSIONS: Any reference criteria were not obtained that surely distinguish patients with PASCS from those with PA or SCS. However, clinicians should suspect the presence of concurrent SCS in patients with PA when detecting a relatively large adrenal tumor on the CT scans.

Suppression of heme oxygenase-1 activity reduces airway hyperresponsiveness and inflammation in a mouse model of asthma.

OBJECTIVE: Carbon monoxide (CO) levels in expired gas are higher in patients with bronchial asthma than in healthy individuals. Heme oxygenase-1 (HO-1) is a rate-limiting enzyme that catalyzes the degradation of heme to yield biliverdin, CO and free iron. Thus, HO-1 is implicated in the pathogenesis of bronchial asthma. However, whether HO-1 expression and activity in lung tissue are related to allergic airway inflammation remains unclear. We investigated whether expression of HO-1 is related to allergic airway inflammation in lungs and whether HO-1 could influence airway hyperresponsiveness and eosinophilia in mice sensitized to ovalbumin (OVA). METHODS: C57BL/6 mice immunized with OVA were challenged thrice with an aerosol of OVA every second day for 8 days. HO-1-positive cells were identified by immunostaining in lung tissue, and zinc protoporphyrin (Zn-PP), a competitive inhibitor of HO-1, was administered intraperitoneally to OVA-immunized C57BL/6 mice on day 23 (day before inhalation of OVA) and immediately before inhalation on the subsequent 4 days (total five doses). Mice were analyzed for effects of HO-1 on AHR, inflammatory cell infiltration and cytokine levels in lung tissue. Ethical approval was obtained from the concerned institutional review board. RESULTS: Number of HO-1-positive cells increased in the subepithelium of the bronchi after OVA challenge, and HO-1 localized to alveolar macrophages. Zn-PP clearly inhibited AHR, pulmonary eosinophilia and IL-5 and IL-13 expression in the lung tissue. CONCLUSION: Expression of HO-1 is induced in lung tissue during attacks of allergic bronchial asthma, and its activity likely amplifies and prolongs allergic airway inflammation.

Neoadjuvant chemotherapy and surgery for transdiaphragmatic liver invasion of primary lung cancer.

A 75-year-old woman presented with intermittent dull abdominal pain, gradually exacerbating over eight months. Computed tomography demonstrated a large mass straddling both the right lower lobe of the lung and the right hepatic lobe. An 18-fluoro-2-deoxy-D-glucose positron emission computed tomography scan (PET/CT) demonstrated high accumulation in the lesion and carinal lymph nodes. Transbronchial biopsy revealed squamous cell carcinoma; thus, primary lung cancer with transdiaphragmatic invasion into the liver was diagnosed. Chemotherapy with carboplatin (AUC = 5) on day one and weekly paclitaxel (70 mg/m2 ) doses were introduced for four courses. The size of the main tumor was reduced and the mediastinal lymph node accumulation disappeared in a subsequent PET/CT. Thus, en-bloc radical resection of the lung tumor by right lower lobectomy with partial resection of invaded middle lobe and the diaphragm, subsegmentectomy of the liver, and standard mediastinal dissection were undertaken. The postoperative course was uneventful and the patient was discharged on day 30. Her nutrition status dramatically improved and she gained five kilograms of body weight in two months following the resection. The patient, however, then had a fall and suffered femur and multiple pelvic fractures and died of acute pneumonia five weeks after the femur fixation and 14 weeks after the lung surgery.

Clinical significance of serum vascular endothelial growth factor in malignant pleural mesothelioma.

INTRODUCTION: Malignant pleural mesothelioma (MPM) is an aggressive malignant tumor of mesothelial origin associated with asbestos exposure. MPM has a limited response to conventional chemotherapy and radiotherapy so diagnosing MPM early is very important. Vascular endothelial growth factor (VEGF) is an autocrine growth factor for MPM. Here, we investigated the serum levels of VEGF in patients with MPM in comparison with a population that had been exposed to asbestos without developing MPM. METHODS: Serum concentrations of VEGF were measured in 51 patients with MPM and 42 individuals with benign asbestos-related diseases (asbestosis or pleural plaques) or who were healthy despite asbestos exposure. RESULTS: We demonstrated that patients with MPM had significantly higher serum levels of VEGF than a population who had been exposed to asbestos but had not developed MPM, and the patients with advanced stage MPM showed higher levels of VEGF than the early stage patients with MPM. The difference in overall survival between the groups with VEGF serum levels lower and higher than the assumed cutoff of 460 pg/ml was significant. CONCLUSIONS: Our data suggest that the VEGF serum concentration could be a useful marker for screening MPM among asbestos-exposed individuals and as a prognostic factor.

[Expression of mesothelin as a potential diagnostic marker in mesothelioma].

Histological discrimination of mesothelioma from adenocarcinoma is often difficult, therefore, many investigators have tried immunohistochemical, ultrastructual, and molecular methods. Economically, immunohistological studies are more excellent, compared with ultrastractual and molecular biological methods. Immunohistologically, many well known markers are divided into two category; adenocarcinoma-related markers, which expressed by adenocarcinoma, and mesothelioma-related makers, which are positive for mesothelioma. CEA, TTF-1, and Ber-Ep4 are well known adenocarcinoma-related markers, mesothelin, TM, HBME-1 and calretinin, have been used as mesothelioma-related markers. Most previous reports associated with discrimination of adenocarcinoma and mesothelioma mentioned that a diagnosis of epithelioid mesothelioma would be excluded by the presence of adenocarcinoma-related antibody. The positive ratio of mesothelioma-related antibodies is lower than that of adenocarcinoma-related antibodies. Only a single mesothelioma-related marker cannot lead to a diagnosis of epithelioid mesothelioma and a correct diagnosis can be made by combination of several makers, which contain both mesothelioma-related markers and adenocarcinoma-related markers. We immunohistologically examined 41 cases of mesothelioma and 16 cases of adenocarcinoma of the lung, and re-evaluated the use of immunohistochemical markers, compared with previous reports. Reactivity for mesothelin was obtained in 19 (73%) of the epithelioid mesotheliomas, but none (0%) of the lung adenocarcinomas. None of the sarcomatoid mesotheliomas exhibited positivity for this marker, nor was any reactivity seen in the spindle cell component of the biphasic mesotheliomas. These findings indicate that, in some instances, mesothelin immunostaining can assist in the diagnosis of mesothelioma.

[A case of primary lung cancer with cervical tuberculous lymphadenitis].

A 66-year-old woman was admitted due to right cervical lymphadenopathy and an abnormal chest radiograph. Acid-fast bacilli smear of fine needle aspiration from a right cervical lymph node was positive. Histopathological examination of the specimen obtained by percutaneous right cervical lymph node biopsy showed necrotizing epithelioid granulomas and no malignant cells. Therefore, right cervical tuberculous lymphadenitis was diagnosed. Partial lung resection of the right S4 was carried out by video-assisted thoracoscopic surgery and primary lung cancer was diagnosed. To our knowledge, there has been no previous report of both primary lung cancer and cervical tuberculous lymphadenitis being present at the time of the first examination. We report this very rare case.

Recombinant human hexamer-dominant IgM monoclonal antibody to ganglioside GM3 for treatment of melanoma.

PURPOSE: L612, a human IgM monoclonal antibody produced by an EBV-transformed human B-cell line, binds to ganglioside GM3 and kills GM3-positive human melanoma cells in the presence of complement. It has been shown to be effective in some patients with late-stage melanoma. L612 consists of hexameric IgM (about 20%), pentameric IgM (about 74%), and other minor IgM molecules. Because hexameric IgM activates complement more effectively than pentameric IgM, we developed and evaluated a hexamer-dominant recombinant IgM for clinical applications. EXPERIMENTAL DESIGN: Chinese hamster ovary (CHO) cells were transfected with heavy- and light-chain genes of L612, with or without the joining-chain gene. Antitumor effects of the recombinant IgM secreted from CHO cells were evaluated in vitro and in vivo. RESULTS: Recombinant IgM secreted from CHO cells without the joining chain (designated CA19) was approximately 80% hexameric, whereas recombinant IgM from CHO cells transfected with heavy-, light-, and joining-chain genes (designated CJ45) was about 90% pentameric. Both CA19 and CJ45 recombinant IgMs caused complement-dependent cytotoxicity against human and mouse melanoma cell lines, but the amount of CA19 required for 50% specific cytotoxicity was 5 to 10 times smaller. I.v. injection of CA19 compared with CJ45 or native L612 elicited more profound antitumor activity in nude rats bearing a GM3-positive mouse melanoma xenograft. CONCLUSIONS: A hexamer-dominant human IgM against GM3 may provide a more potent treatment option for patients with GM3-positive melanoma.

Antitumor activity of a monoclonal antibody against CD47 in xenograft models of human leukemia.

The ligation of CD47 induces the apoptosis of leukemic cells in a caspase-independent manner. We generated a monoclonal antibody against CD47 (mAb-MABL) that possibly induced apoptosis from the ligation of CD47 in CCRF-CEM and JOK-1 cells in vitro. To confirm whether the ligation of CD47 caused cell death in vivo, we examined the antitumor activity of F(ab')2 of mAb-MABL in two xenograft models: The acute lymphoblastic leukemia (CCRF-CEM) and the B-cell chronic lymphocytic leukemia (JOK-1) cell line. Furthermore, in order to clarify the apoptotic activity selective for the tumor cells, we examined F(ab')2 of mAb-MABL apoptotic effects on CD34+ hematopoietic progenitor/stem and human endothelial cells. Male SCID mice were intravenously injected with CCRF-CEM (5 x 10(6) cells/mouse) or JOK-1 cells (5 x 10(6) cells/mouse) and intraperitoneally with JOK-1 cells (2 x 10(7) cells/mice). After the implantation of the cells, the mice were intravenously administered the vehicle or the F(ab')2 fragment of mAb-MABL at several doses and the length of survival was measured. F(ab')2 of mAb-MABL markedly prolonged the survival of mice transplanted with CCRF-CEM and JOK-1. Significantly, 40% of the mice intraperitoneally injected with JOK-1 cells became tumor-free when administered F(ab')2 of mAb-MABL, whereas even a high dose of fludarabine only slightly prolonged the median survival time. On the contrary, F(ab')2 of mAb-MABL showed no apoptotic effect on CD34+ hematopoietic progenitor/stem or human endothelial cells. Thus, monoclonal antibodies that cause cell death from the ligation of CD47 could be novel therapeutic agents for incurable leukemia after further optimization such as humanization or making single chain diabodies.

Vascular effects of a common gene variant of extracellular superoxide dismutase in heart failure.

A common gene variant of human extracellular superoxide dismutase (ecSOD), in approximately 5% of humans, is associated with increased risk of ischemic heart disease. The purpose of this study was to examine vascular effects of ecSOD with effects of the ecSOD variant (ecSOD(R213G)) in rats with heart failure. Seven weeks after coronary artery ligation, we studied rats with heart failure and sham-operated rats. Adenoviral vectors expressing human ecSOD, ecSOD(R213G), or a control virus were injected intravenously. In the aorta from rats with heart failure, responses to acetylcholine (69 +/- 4% relaxation, means +/- SE) and basal levels of nitric oxide (NO) (vasoconstrictor responses to a NO synthase inhibitor) were greatly impaired, and levels of superoxide and peroxynitrite were increased. Gene transfer of ecSOD restored responses to acetylcholine (92 +/- 2% relaxation) and basal levels of NO to normal and reduced levels of superoxide [from 2.3 +/- 0.2 to 0.9 +/- 0.2 relative light units per second per millimeter squared (RLU x s(-1) x mm(-2))] and peroxynitrite (from 2.4 +/- 0.2 to 0.9 +/- 0.1 RLU x s(-1) x mm(-2)) in the aorta from rats with heart failure. Gene transfer of ecSOD(R213G) produced little or no improvement. Responses to nitroprusside were not different among the groups. Expression of endogenous mRNA for SODs (CuZnSOD, MnSOD, and ecSOD) and endothelial NOS in the aorta was not different among the groups. In contrast to ecSOD, gene transfer of ecSOD(R213G) in rats with heart failure has minimal beneficial effect on oxidative stress, endothelial function, or basal bioavailability of NO. We speculate that greatly diminished efficacy of ecSOD(R213G) in protection against oxidative stress and endothelial dysfunction may contribute to increased risk of cardiovascular disease in humans with ecSOD(R213G).

Renal thrombotic microangiopathy in a genetic model of hypertension in mice.

Our goal was to develop a model of accelerated hypertension with renal microangiopathy. Transgenic mice that are hypertensive because of overexpression of human renin (R+ mice) and human angiotensin (A+ mice) genes were studied. To increase arterial pressure to levels comparable to those that may be seen in malignant hypertension, high salt was added to the diet and/or the nitric oxide synthase inhibitor, N(omega)-nitro-L-arginine methylester (L-NAME), was added to the drinking water. Renal lesions, decline in renal function, and proteinuria developed within 10 weeks in R+/A+ mice given both L-NAME and a high-salt diet, and within 24 weeks in mice given either L-NAME or a high-salt diet. Renal morphology showed features of severe thrombotic microangiopathy, with extensive vascular and glomerular lesions in all R+/A+ mice on high salt, L-NAME, or high salt plus L-NAME. Vascular lesions included fibrin thrombi and onion skinning of the vessel walls, whereas glomerular lesions included segmental sclerosis, mesangiolysis, fibrin thrombi within glomerular capillaries, and double-contour formation of glomerular capillary walls. Renal morphology was normal in control mice fed high salt and/or L-NAME. No R+/A+ mice fed a normal diet developed vascular lesions, whereas a few mice developed mild focal glomerular lesions. In summary, these studies characterize vascular and glomerular lesions in R+/A+ mice fed high salt, L-NAME, or both high salt and L-NAME, and provide a murine model of malignant hypertension with renal thrombotic microangiopathy.