Fumihiro Kimura

AN ESSENTIAL ROLE FOR NUCLEAR FACTOR KAPPA B IN PREVENTING TNF-alpha-INDUCED CELL DEATH IN PROSTATE CANCER CELLS

PURPOSE Although tumor necrosis factor-alpha (TNF-alpha) induces a strong cytotoxic effect on cell growth, many authors have reported that various cancer cells are resistant to TNF-alpha and the basis for this sensitivity or resistance to TNF-alpha remains to be elucidated. Since nuclear factor kappa B (NF-kappaB) activation has recently been reported to inhibit TNF-alpha-induced cell death, we studied whether NF-kappaB also assumes a protective role in TNF-alpha-induced cell death in prostate cancer cells. MATERIALS AND METHODS We used two human prostate cancer cell lines of DU145 and PC-3. We prepared two different NF-kappaB inhibitors, pyrrolidine dithiocarbamate (PDTC) and NF-kappaB decoy. NF-kappaB DNA binding activity was detected by electrophoretic mobility shift assay (EMSA). Cell survivals were measured by MTT assay. Induction of apoptosis was detected by nuclear staining and measured by fragmented DNA ELISA. RESULTS EMSA showed that NF-kappaB inhibitors continuously inhibited TNF-alpha-induced NF-kappaB activation. Cell growth was not inhibited by either TNF-alpha (50 ng./ml. or less) or NF-kappaB inhibitors. However, both PCA cells treated with TNF-alpha (20 ng./ml.) plus NF-kappaB inhibitors showed significant growth inhibition compared with controls (p<0.05). Nuclei of PCA cells appeared severely fragmented by this combination therapy. Furthermore, the levels of DNA fragmentation were significantly elevated in PCA cells treated with TNF-alpha (20 ng./ml.) plus NF-kappaB inhibitors compared with controls (p<0.05). CONCLUSIONS NF-kappaB activation is suggested to produce the resistance of DU145 and PC-3 to TNF-alpha and that the combination of TNF-alpha and NF-kappaB inhibitors could be constituted an effective therapy to TNF-alpha-resistant human prostate cancer cells.

A Distinct mRNA Encoding a Soluble Form of ICAM-1 Molecule Expressed in Human Tissues

A soluble form of ICAM-1 (sICAM-1) have been observed in normal human serum (Rothlein et al., J. Immunol. 147, 3788-3793) and at elevated levels in inflammatory and tumor bearing status (Seth et al., Lancet, 338, 83-84; Giavazzi et al., Canc. Res. 52, 2628-2630; Harning et al., Canc. Res., 51, 5003-5005). However, the mechanism to produce the sICAM-1 has been still unknown. In this report we presented evidence for the presence of the mRNA specifically encoding sICAM-1, which is probably generated by alternative splice donor site selection. A 19-base deletion occurred right upstream of the transmembrane region gave rise to reading frameshift and eliminate the entire transmembrane and cytoplasmic domains, resulting in incapability of ICAM-1 molecules to reside in the membrane. A reverse transcription-polymerase chain reaction (RT-PCR) using a primer pair specific to sICAM-1 revealed a positive expression in all tissues analyzed, though the amount and the ratio to the conventional species varied slightly from tissue to tissue. Inflammatory cytokines displayed a complex pattern in the ICAM-1 mRNA expression depending on the combination of cytokines and the cultured cell lines used.

Transformation-associated gene regulation by ATF6α during hepatocarcinogenesis

We have previously reported that the endoplasmic reticulum (ER) stress‐regulated transmembrane transcription factor 6 α (ATF6α) is implicated in the pathogenesis of hepatocellular carcinomas (HCCs). In order to further identify genes that are regulated by ATF6α, the global gene expression profiles of the ATF6α‐transfected and untransfected HCC cell line, HLF, were analyzed. These results were then compared with the differential gene expression patterns of poorly differentiated HCC and control non‐tumorous liver tissue. Our findings demonstrate that at least 18 genes are specifically upregulated by ATF6α, while another UPR mediator, XBP1 or ER‐stress inducer, thapsigargin could partially stimulate or even repress some of them in HCC cells. Moreover, six of these identified genes contain potential ER stress‐responsive elements and/or unfolded protein response elements in their 5′ regulatory regions.

Decreased Serum Adiponectin Levels in Patients with Metastatic Renal Cell Carcinoma

BACKGROUND Low levels of serum adiponectin are associated with increased risk and aggressiveness of obesity-related cancer. The purpose of the study reported here was to investigate the association between serum adiponectin levels and clinicopathological parameters of renal cell carcinoma. METHODS Preoperative serum total and high-molecular-weight (HMW) adiponectin levels were measured in 118 patients with renal cell carcinoma, and their association with clinicopathological parameters was analysed. RESULTS There were no statistically significant associations between total adiponectin and HMW adiponectin and pathological stage, regional lymph node involvement, histological grade, histological type (clear cell carcinoma versus other types) or presence of venous invasion. Total and HMW adiponectin levels in patients with metastasis, however, were significantly lower than in patients without metastasis (P = 0.044 for total adiponectin and P = 0.041 for HMW adiponectin). Low total and HMW adiponectin levels were significantly associated with metastasis in patients with a normal BMI (<25 kg/m(2)) (P = 0.034 for total adiponectin and P = 0.028 for HMW adiponectin) but not in overweight and obese patients (P = 0.652 for total adiponectin and P = 0.489 for HMW adiponectin). Multivariate logistic regression analysis showed that total adiponectin level was an independent predictor of metastasis of renal cell carcinoma in all patients (P = 0.024, 95% CI = 1.031-1.560) and in patients with a normal BMI (P = 0.040, 95% CI = 1.043-6.534). CONCLUSIONS Serum total and HMW adiponectin levels were decreased in patients with metastatic renal cell carcinoma. Adiponectin might be a molecular link between obesity and the progression of renal cell carcinoma.

Intratumoral Lymphatics and Lymphatic Invasion Are Associated with Tumor Aggressiveness and Poor Prognosis in Renal Cell Carcinoma

OBJECTIVES Because lymphangiogenesis and lymphatic invasion are key steps to nodal involvement in various types of cancer, we examined the clinicopathologic significance of lymphangiogenesis and lymphatic invasion in renal cell carcinoma. METHODS Peritumoral lymphatics and intratumoral lymphatics (ITLs) from 106 patients with clear cell renal cell carcinoma specimens were immunostained with D2-40 antibody, which specifically recognizes the lymphatic-specific marker podoplanin. The clinicopathologic significance of the densities and presence of lymphatic vessels and lymphatic invasion (LVI) was evaluated, and the staining pattern of D2-40 was compared with that of CD34. RESULTS Peritumoral lymphatics were present in 100 patients (94.3%), and ITLs were present in only 20 (18.9%). LVI was present in 6 patients (5.7%), of whom 5 had concomitant microvascular invasion. Some lymphatic vessels were positive not only for D2-40, but also for CD34. The presence of ITLs and LVI were significantly associated with pathologic T stage (P <0.0001 and P = 0.0136, respectively), regional lymph node involvement (P = 0.0312 and P = 0.0067, respectively), distant metastasis (P = 0.0046 and P = 0.0294, respectively), and microvascular invasion (P = 0.0105 and P = 0.0312, respectively). Univariate analysis showed that patients with ITLs had significantly shorter cancer-specific survival than those without ITLs (P = 0.0025) but multivariate analysis did not (P = 0.0527). CONCLUSIONS The results of our study have shown that ITLs and LVI are associated with tumor aggressiveness, and patients with ITL have poor prognosis in renal cell carcinoma. One should be aware that some of the intratumoral microvessels are lymphatics and patients with microvascular invasion evident on the routine histologic examination often also have LVI.