Hiroyuki Yonou

Growth Inhibition of Human Prostate Cancer Cells in Human Adult Bone Implanted into Nonobese Diabetic/Severe Combined Immunodeficient Mice by a Ligand-Specific Antibody to Human Insulin-Like Growth Factors

Advanced prostate cancer frequently involves the bone that has the largest content of insulin-like growth factors (IGFs). However, the role of bone-derived IGFs in bone metastasis of prostate cancer has not been studied extensively because of the lack of a reliable animal model. Therefore, we investigated whether a novel antibody directed against human IGF-I and IGF-II (KM1468) could inhibit the development of new bone tumors and the progression of established bone tumors in nonobese diabetic/severe combined immunodeficient mice implanted with human adult bone. We first confirmed that KM1468 bound specifically to human IGF-I, human IGF-II, and mouse IGF-II but not to insulin. It also blocked autophosphorylation of the type I IGF receptor induced by the binding of IGFs in human-type I IGF receptor-overexpressing BALB/c 3T3 cells, and it inhibited the IGF-stimulated growth of MDA PCa 2b cells in vitro. Then mice were injected intraperitoneally with KM1468 once weekly for 4 weeks either immediately or 4 weeks after inoculation of MDA PCa 2b cells. KM1468 markedly and dose-dependently suppressed the development of new bone tumors and the progression of established tumor foci, as determined by histomorphometry, and it also decreased serum prostate-specific antigen levels, compared with the control. This is the first report of an IGF ligand-specific inhibitory antibody that suppresses the growth of human prostate cancer cells in human adult bone. These results indicate that the IGF signaling axis is a potential target for prevention and treatment of bone metastases arising from prostate cancer.

URINARY SATURATION AND RISK FACTORS FOR CALCIUM OXALATE STONE DISEASE BASED ON SPOT AND 24-HOUR URINE SPECIMENS

In 222 random spot urine specimens, the calcium concentration and calcium oxalate saturation [DG(CaOx)] were significantly higher among stone formers than among non-stone formers, while the citrate and creatinine-corrected citrate concentrations were lower. In 188 24-hour urine specimens, magnesium excretion was lower among stone formers than non-stone formers, while the creatinine-corrected calcium concentration and DG(CaOx) were higher. Among stone formers, there was no gender difference in the urinary concentrations of calcium, oxalate, citrate, magnesium, and DG(CaOx), but the creatinine-corrected calcium, citrate, and magnesium concentrations were higher in women, as well as 24-hour citrate excretion. The levels of calcium and oxalate have a major influence on DG(CaOx), while citrate and magnesium levels have a minor influence. DG(CaOx) was correlated with calcium and oxalate excretion, as well as with the creatinine-corrected calcium and oxalate concentrations. Approximately 5% of 24-hour urine specimens showed critical supersaturation, 80% showed metastable supersaturation, and 15% were unsaturated. Hypercalciuria or hyperoxaluria was fairly common (30% and 40%) in critically supersaturated urine, while it was less common (22.4% and 8.6%) in metastably supersaturated urine and was not detected in unsaturated urine. Hypocitraturia and/or hypomagnesiuria was more common (63.8-80%) at any saturation. The urinary calcium, oxalate, and citrate concentrations, as well as the creatinine-corrected calcium, oxalate, citrate, and magnesium concentrations and DG(CaOx), showed a significant correlation between 57 paired early morning spot urine and 24-hour urine specimens. The creatinine-corrected calcium and citrate concentrations of the early morning urine specimens were significantly correlated with the levels of calcium and citrate excretion in the paired 24-hour urine specimens. In conclusion, no parameter other than urinary saturation gives more than a vague indication of the risk of lithogenesis, so DG(CaOx) in either early morning urine or 24-hour urine specimens appears to be the best predictor of stone risk. Finally, the creatinine-corrected calcium and citrate concentrations in early morning urine can be used as a substitute for measuring 24-hour excretion.

Hyaluronan synthase expression in pleural malignant mesotheliomas

Hyaluronan (HA) is thought to play several important roles in tumor growth, tumorigenicity, and tumor dissemination and metastasis. Recently, three isoforms of hyaluronan synthase (HAS) have been cloned. Our objective was to determine which of the HAS isoforms were expressed in pleural malignant mesotheliomas, the most representative lesion of HA-producing tumors. We studied 10 cases of pleural malignant mesothelioma using novel antibodies of HAS. We compared HAS expression patterns of mesothelioma and pulmonary adenocarcinoma. Immunohistochemically, 9 of 10 (90%) cases of mesothelioma had extensive reaction to anti-HAS1 and anti-HAS2 antibodies, while HAS3 overexpression was present in 4 of 10 cases (40%). Of 20 cases of pulmonary adenocarcinoma, 5 overexpressed HAS1 (25%), 16 of 20 HAS2 (80%), and 4 of 20 HAS3 (20%). The expression level of HAS1 was significantly higher in mesotheliomas than in pulmonary adenocarcinoma (P=0.0036). Our data suggests that HAS1 might be a useful positive marker of malignant mesothelioma. However, a definitive conclusion should be based on further large-scale studies.

Transitional cell carcinoma of the renal pelvis forming tumor thrombus in the vena cava

Abstract A 47‐year‐old man presented with a left renal incidentaloma without hematuria. The tumor was complicated by inferior vena cava (IVC) thrombus extending from Th11 to L4. A temporary IVC filter was introduced prior to surgery. A midline incision was used to perform a left radical nephrectomy and en bloc lymphadenectomy with excision of the inferior vena cava from above the level of the left renal vein to 2.5 cm above the confluence of the common iliac veins. The pathological diagnosis was invasive transitional cell carcinoma. The tumor thrombus consisted of transitional cell carcinoma that histologically invaded the walls of the IVC. He died of cancer 17 months after the operation for the liver metastases. This is the 18th case report of such a presentation in the literature.

Prostate-specific antigen enhances bioavailability of insulin-like growth factor by degrading insulin-like growth factor binding protein 5

In the bone matrix, insulin-like growth factors (IGFs) are the most abundant growth factors and IGF binding protein 5 (IGFBP-5) is the major IGFBP. Our previous study suggested that IGFs stored in the bone matrix and prostate-specific antigen (PSA) play an important role in prostate cancer (PC) bone metastasis. However, it is not clear how IGF signaling is activated in the bone microenvironment of PC metastasis. Therefore, we investigated whether PSA degrades IGFBP-5 and enhances biological activity of IGF. Enzymatically active PSA degraded the recombinant IGFBP-5 protein in a dose- and time-dependent manner and a serine protease inhibitor suppressed this degradation. Furthermore, PSA induced IGF-mediated type I IGF receptor phosphorylation that was inhibited by coincubation with IGFBP-5. The present study indicates PSA derived from PC cells can enhance IGF bioavailability in the bone microenvironment of PC metastasis, thereby permitting PC survival and malignant progression in the bone microenvironment.

Topographical distribution of allelic loss in individual lung adenocarcinomas with lymph node metastases

Adenocarcinomas of the lung are characterized by morphological heterogeneity, and since carcinogenesis has been suggested to be a multistep process involving sequential accumulation of multiple genetic alterations, the morphological heterogeneity may represent a cross-sectional view of genetic alterations within individual tumors. Therefore, to elucidate whether, and which, genetic alterations accumulated in relation to morphological cancer progression, we examined 56 microdissected sites for topographical distribution of loss of heterozygosity (LOH) in 12 adenocarcinomas of the lung with bronchioloalveolar (BA) and invasive components in their primary tumors and metastases to lymph nodes. The morphological changes from noninvasive BA lesions to invasive and metastatic components were characterized by a significant rise in the prevalence of allelic losses (P<0.05). Individually, eight cases (67%) showed accumulation of genetic alterations from BA lesions to metastases. LOHs in multiple foci in one case were compared to determine whether they were shared at all tumor sites as an early event or localized in metastases as an additional event. LOHs at 5q and 17p may be crucial steps in the early phase of development to metastasis, while 18q loss may be an additional step. These findings suggested that the cancer cells in some pulmonary adenocarcinomas evolved from the BA lesions to the invasive and metastatic lesions.

Engraftment of Adult Human Lung Tissue in Nonobese Diabetic/Severe Combined Immunodeficient Mice: A Novel Lung Epithelial Regeneration Model

Objectives: Injury causes the disruption of homeostatic cell-cell interactions and epithelial regeneration is part of the threshold response. Due to the lack of a good animal model for the investigation of these mechanisms, the kinetics of cell proliferation after injury to the human respiratory tract are poorly understood. Methods: To create a better model of human bronchioloalveolar epithelial regeneration, we engrafted adult human lung tissue into nonobese diabetic/severe combined immunodeficient (NOD/SCID) mice. Then the lung tissue was studied at various times up to 20 weeks after implantation. Results: The xenografts of bronchiolar epithelium showed characteristic features, including positivity for specific human antigens, and extensive regeneration was observed within 8 weeks after implantation. In addition, a few alveolar type II epithelial cells expressing prosurfactant protein C were detected in some areas. The distal alveolar spaces were filled with protein-rich material and were markedly dilated. Abundantly ciliated secretory epithelium, which was similar to normal adult bronchiolar epithelium, was observed within 16 weeks after implantation in the mice. All of the human lung tissue specimens that were implanted subcutaneously into the backs of the mice developed well and remained viable for 20 weeks. Each type of adult human lung epithelial cell showed a different mode of proliferation. Bronchiolar epithelial cells proliferated earlier, with MIB-1 labeling of up to 20% of the cells in the grafts at 8 weeks, while alveolar type II cells proliferated later, with labeling of up to 5% of graft cells at 12 weeks. Conclusion: This model seems to allow adult human lung epithelial regeneration to be investigated in vivo over the long term.