Randomized clinical trial of adjuvant gemcitabine chemotherapy versus observation in resected bile duct cancer.

BACKGROUND: Although some retrospective studies have suggested the value of adjuvant therapy, no recommended standard exists in bile duct cancer. The aim of this study was to test the hypothesis that adjuvant gemcitabine chemotherapy would improve survival probability in resected bile duct cancer. METHODS: This was a randomized phase III trial. Patients with resected bile duct cancer were assigned randomly to gemcitabine and observation groups, which were balanced with respect to lymph node status, residual tumour status and tumour location. Gemcitabine was given intravenously at a dose of 1000 mg/m2 , administered on days 1, 8 and 15 every 4 weeks for six cycles. The primary endpoint was overall survival, and secondary endpoints were relapse-free survival, subgroup analysis and toxicity. RESULTS: Some 225 patients were included (117 gemcitabine, 108 observation). Baseline characteristics were well balanced between the gemcitabine and observation groups. There were no significant differences in overall survival (median 62·3 versus 63·8 months respectively; hazard ratio 1·01, 95 per cent c.i. 0·70 to 1·45; P = 0·964) and relapse-free survival (median 36·0 versus 39·9 months; hazard ratio 0·93, 0·66 to 1·32; P = 0·693). There were no survival differences between the two groups in subsets stratified by lymph node status and margin status. Although haematological toxicity occurred frequently in the gemcitabine group, most toxicities were transient, and grade 3/4 non-haematological toxicity was rare. CONCLUSION: The survival probability in patients with resected bile duct cancer was not significantly different between the gemcitabine adjuvant chemotherapy group and the observation group. Registration number: UMIN 000000820 (http://www.umin.ac.jp/).

Cloning and functional analysis of human p51, which structurally and functionally resembles p53.

The p53 tumor suppressor gene, which is induced by DNA damage and/or stress stimuli, causes cells to undergo G1-arrest or apoptotic death; thus it plays an essential role in human carcinogenesis. We have searched for p53-related genes by using degenerate PCR, and have identified two cDNA fragments similar to but distinct from p53: one previously reported, p73, and the other new. We cloned two major splicing variants of the latter gene and named these p51A and p51B (a human homologue of rat Ket). The p51A gene encodes a 448-amino-acid protein with a molecular weight of 50.9 kDa; and p51B, a 641-amino-acid protein with a molecular weight of 71.9 kDa. In contrast with the ubiquitous expression of p53, expression of p51 mRNA was found in a limited number of tissues, including skeletal muscle, placenta, mammary gland, prostate, trachea, thymus, salivary gland, uterus, heart and lung. In p53-deficient cells, p51A induced growth-suppression and apoptosis, and upregulated p21waf-1 through p53 regulatory elements. Mutations in p51 were found in some human epidermal tumors.

Gemcitabine alone or in combination with cisplatin in patients with biliary tract cancer: a comparative multicentre study in Japan.

BACKGROUND: A British randomised study of gemcitabine plus cisplatin (GC) combination showed promising results in biliary tract cancer (BTC) patients. In our study, we evaluated the efficacy and safety of this combination compared with gemcitabine alone (G) in Japanese BTC patients. METHODS: Overall, 84 advanced BTC patients were randomised to either cisplatin 25 mg m(-2) plus gemcitabine 1000 mg m(-2) on days 1, 8 of a 21-day cycle (GC-arm), or single-agent gemcitabine 1000 mg m(-2) on days 1, 8 and 15 of a 28-day cycle (G-arm). Treatments were repeated for at least 12 weeks until disease progression or unacceptable toxicity occurred, up to a maximum of 48 weeks. RESULTS: A total of 83 patients were included in the analysis. For the GC and G-arms, respectively, the 1-year survival rate was 39.0 vs 31.0%, median survival time 11.2 vs 7.7 months, median progression-free survival time 5.8 vs 3.7 months and overall response rate 19.5 vs 11.9%. The most common grade 3 or 4 toxicities (GC-arm/G-arm) were neutropenia (56.1%/38.1%), thrombocytopenia (39.0%/7.1%), leukopenia (29.3%/19.0%), haemoglobin decrease (36.6%/16.7%) and gamma-GTP increase (29.3%/35.7%). CONCLUSIONS: Gemcitabine plus cisplatin combination therapy was found to be effective and well tolerated, suggesting that it could also be a standard regimen for Japanese patients.

Percutaneous transhepatic biliary drainage catheter tract recurrence in cholangiocarcinoma.

BACKGROUND: The aim of the study was to clarify the incidence, risk factors and treatment of percutaneous transhepatic biliary drainage (PTBD) catheter tract recurrence in patients with resected cholangiocarcinoma. METHODS: The medical records of 445 patients with perihilar and distal cholangiocarcinoma who underwent resection following PTBD were reviewed retrospectively. RESULTS: PTBD catheter tract recurrence was detected in 23 patients (5.2 per cent). The mean(s.d.) interval between surgery and onset of the recurrence was 14.4(13.8) months. On multivariable analysis, duration of PTBD (60 days or more), multiple PTBD catheters and macroscopic papillary tumour type were identified as independent risk factors. In four patients with synchronous metastasis, the PTBD sinus tract was resected simultaneously, at the time of initial surgery. Of 19 patients with metachronous metastasis, 15 underwent surgical resection of the metastasis. Survival of the 23 patients with PTBD catheter tract recurrence was poorer than that of the 422 patients without recurrence (median 22.8 versus 27.3 months; P = 0.095). Even after surgical resection of PTBD catheter tract recurrence, survival was poor. CONCLUSION: PTBD catheter tract recurrence is not unusual. The prognosis for these patients is generally poor, even after resection. To prevent this troublesome complication, endoscopic biliary drainage is first recommended when drainage is indicated.

The concept of perihilar cholangiocarcinoma is valid.

BACKGROUND: The term perihilar cholangiocarcinoma has been used for all tumours involving or requiring resection of the hepatic confluence. However, it does not distinguish between intrahepatic and extrahepatic hilar tumours, and has no clinicopathological basis. This retrospective study examined whether the concept of perihilar cholangiocarcinoma is valid clinically. METHODS: Some 250 patients with perihilar cholangiocarcinoma were divided into extrahepatic (EHC, 167 patients) and intrahepatic (IHC, 83) groups based on tumour location. Clinicopathological data were compared between these groups. RESULTS: Liver, portal vein, venous and lymphatic invasion, and nodal metastasis were more common in IHCs than EHCs, whereas histological grade and incidence of perineural invasion were similar. IHCs were more advanced at the time of surgery; stage III or IV disease was found in 37.7 per cent of EHCs and 59 per cent of IHCs. Survival was marginally better for patients with EHCs than for those with IHCs (29.3 versus 20 per cent at 5 years; P = 0.057), but survival rates were similar for each tumour stage in the American Joint Committee on Cancer classification. CONCLUSION: Combining EHC and IHC under the term perihilar cholangiocarcinoma is valid, as these tumours have comparable biological behaviour, with similar clinical management depending on stage and invasion.

CLCP1 interacts with semaphorin 4B and regulates motility of lung cancer cells.

We previously established a highly metastatic subline, LNM35, from the NCI-H460 lung cancer cell line, and demonstrated upregulation of a novel gene, CLCP1 (CUB, LCCL-homology, coagulation factor V/VIII homology domains protein), in LNM35 and lung cancer specimens. In this study, we focused on the potential roles of that gene in cancer metastasis. First, we established stable LNM35 RNAi clones, in which CLCP1 expression was suppressed by RNAi, and found that their motility was significantly reduced, although growth rates were not changed. Next, in vitro selection of a phage display library demonstrated that a phage clone displaying a peptide similar to a sequence within the Sema domain of semaphorin 4B (SEMA4B) interacted with LNM35. Immunoprecipitation experiments confirmed interaction of CLCP1 with SEMA4B, regulation of CLCP1 protein by ubiquitination and proteasome degradation enhanced in the presence of SEMA4B. These results are the first to indicate that CLCP1 plays a role in cell motility, whereas they also showed that at least one of its ligands is SEMA4B and that their interaction mediates proteasome degradation by CLCP1. Although the physiological role of the interaction between CLCP1 and SEMA4B remains to be investigated, this novel gene may become a target of therapy to inhibit metastasis of lung cancers.

Apoptosis induction by antisense oligonucleotides against miR-17-5p and miR-20a in lung cancers overexpressing miR-17-92.

Amplification and overexpression of the miR-17-92 microRNAs (miRNA) cluster at 13q31.3 has recently reported, with pointers to functional involvement in the development of B-cell lymphomas and lung cancers. In the present study, we show that inhibition of miR-17-5p and miR-20a with antisense oligonucleotides (ONs) can induce apoptosis selectively in lung cancer cells overexpressing miR-17-92, suggesting the possibility of 'OncomiR addiction' to expression of these miRNAs in a subset of lung cancers. In marked contrast, antisense ONs against miR-18a and miR-19a did not exhibit such inhibitory effects, whereas inhibition of miR-92-1 resulted in only modest reduction of cell growth, showing significant distinctions among miRNAs of the miR-17-92 cluster in terms of their roles in cancer cell growth. During the course of this study, we also found that enforced expression of a genomic region, termed C2, residing 3' to miR-17-92 in the intron 3 of C13orf25 led to marked growth inhibition in association with double stranded RNA-dependent protein kinase activation. Finally, this study also revealed that the vast majority of C13orf25 transcripts are detected as Drosha-processed cleavage products on Northern blot analysis and that a novel polyadenylation site is present 3' to the miR-17-92 cluster and 5' to the C2 region. Taken together, the present findings contribute towards better understanding of the oncogenic roles of miR-17-92, which might ultimately lead to the future translation into clinical applications.

Fundamental study of small interfering RNAs for ganglioside GD3 synthase gene as a therapeutic target of lung cancers.

Gangliosides GD3 and GD2 are specifically expressed in neuro-ectoderm-derived tumors, and are considered to play roles in the malignant properties of those cells. We analysed effects of small interfering (si) RNAs against GD3 synthase gene on the expression of ganglioside GD2 and biological phenotypes of human lung cancer cells expressing GD2. An siRNA could suppress the mRNA level of GD3 synthase gene even by single transfection, whereas repeated transfection was required to suppress GD2 expression on the cell surface. Significant reduction in the cell growth and invasion activity was observed in both lung cancer cell lines examined, when repeatedly transfected with the siRNA twice a week. DNA ladder formation was observed after third transfection, indicating the potent induction of apoptosis. Stable transfection of an RNAi expression vector with H1 RNA promoter was also examined. Transfectant cells with the RNAi expression vector showed almost equivalent suppression of GD2 expression and tumor properties in vitro. Furthermore, the stable transfectant cells showed slower cell growth than the control cells in severe combined immunodeficiency mice. These results suggested that siRNAs and/or RNAi expression vectors to generate siRNAs are promising approach to overcome human lung cancers.

Arg660Ser mutation in Thermus aquaticus DNA polymerase I suppresses T-->C transitions: implication of wobble base pair formation at the nucleotide incorporation step.

We examined the replication fidelity of an Arg660Ser (R660S) mutant of Thermus aquaticus DNA polymerase I (Taq pol I). In a forward mutation assay, R660S showed a marked reduction in T-->C transitions, one of the most frequent errors made by the wild-type enzyme. Steady-state kinetics showed that R660S discriminates against dGTP incorporation at a template T 13-fold better than the wild-type. R660S was also 3.2-fold less efficient than the wild-type at extending a T:dG mismatch. These results indicate that R660S has enhanced fidelity during incorporation and extension, which reduces its T-->C transition frequency. Interestingly, R660S also discriminated correct from incorrect nucleotides at the incorporation step of C:dATP, A:dATP, G:dATP and C:8-OH-dGTP mispairs 28-, 6.0-, 4.1- and 6.8-fold better, respectively, than the wild-type, although it may not always be as accurate as the wild-type at the extension step. A structural model suggests that Arg660 may participate in two interactions that influence fidelity; the guanidinium group of Arg660 might interact with the incoming guanine base at the major groove and it might compete for forming another interaction with the primer terminus. Substituting Arg with Ser may eliminate or alter these interactions and destabilize the closed complex with incorrect substrates. Our data also suggest that T:dGTP and C:dATP base pairs form 'wobble' structures at the incorporation step of Taq pol I.

Invasion activating caveolin-1 mutation in human scirrhous breast cancers.

We looked for mutations in the caveolin-1 gene, encoding a critical molecule for membrane signaling to cell growth, in 92 primary human breast cancers, and we report here the identification of a mutation in caveolin-1 at codon 132 (P132L) in 16% of cases. The mutation-positive cases were mostly invasive scirrhous carcinomas. In cell lines expressing the same mutant of caveolin-1, we observed that the mutant Caveolin-1 expression seemed to induce cellular transformation and activation of mitogen-activated protein kinase-signaling pathway and to promote invasion-ability as well as altered actin networks in the cells. These results provide, for the first time, genetic evidence that a functioning Caveolin-1 mutation may have a role in the malignant progression of human breast cancer.

Stimulated rat liver mitochondrial biogenesis after partial hepatectomy.

In order to elucidate the response of mitochondria to the increase in cellular energy demand after hepatectomy, we have examined the effects of partial hepatectomy and hepatic artery ligation on the energy-transducing system of rat liver mitochondria. Specific content of DNA in the mitochondria increased on the first day after the hepatectomy and reached 150% of the original value. Oxidative phosphorylation capacity of the mitochondria started to increase on the first postoperative day. In contrast, specific enzymic activities, specific cytochrome contents, and subunit contents of the energy-transducing complexes in the isolated mitochondria were significantly increased only from the second postoperative day. The ligation of the hepatic artery did not inhibit the amplification of the mitochondrial function. The immunostain for ubiquinol-cytochrome c oxidoreductase was increased predominantly in the portal area of the hepatic lobules of the hepatectomized rats. These results suggest that enhancement of the mitochondrial oxidative phosphorylation system after hepatectomy is based on the increase of the amount of the complexes in the inner membrane, which is closely related to replication of mitochondrial DNA, and that the blood supply from the hepatic artery is not an important factor in the mitochondrial amplification in rats.

Mutation, allelotyping, and transcription analyses of the p73 gene in prostatic carcinoma.

A novel gene, p73, encoding a protein with significant homology to p53, was recently identified at 1p36. To investigate penetrance of p73 in prostatic carcinogenesis, mutation, allelotyping, and transcription analyses of p73 were performed in prostatic carcinoma. No types of mutation causing amino acid substitutions or frameshifts were found in 106 cases examined. Loss of heterozygosity in the gene was found in 2 of 38 cases (5.3%). Various expression levels of p73 alpha variant were observed in tumor compared with those in normal tissue. These data suggest that the p73 gene is not playing an essential role, but expression of p73 may associate with tumor growth in prostatic carcinogenesis.

Glial cell line-derived neurotrophic factor/neurturin-induced differentiation and its enhancement by retinoic acid in primary human neuroblastomas expressing c-Ret, GFR alpha-1, and GFR alpha-2.

Neuroblastomas often undergo spontaneous differentiation and/or regression in vivo, which is at least partly regulated by the signals through neurotrophins and their receptors. Recently, glial cell line-derived neurotrophic factor (GDNF) and a second family member, neurturin (NTN), have been found to mediate their signals by binding to a heterotetrameric complex of c-Ret tyrosine kinase receptors and glycosylphosphatidylinositol-linked proteins, GFR alpha-1 (GDNFR-alpha) or GFR alpha-2 (TrnR2/GDNFR-beta/NTNR-alpha/RETL2). Here, we studied the effect of GDNF and NTN on human neuroblastomas in the short-term primary culture system, as well as the expression of c-Ret, GFR alpha-1, GFR alpha-2, GDNF, and NTN. GDNF (1-100 ng/ml) induced morphological differentiation in 34 of 38 primary neuroblastomas and an accompanying increase in c-Fos induction. These effects were markedly enhanced by treatment with 5 microM all-trans-retinoic acid. Although GDNF alone induced a rather weak differentiation independent of the disease stages, the enhancement of neurite outgrowth induced by treatment with both GDNF and all-trans-retinoic acid was significantly correlated with younger age (less than 1 year; P = 0.0039), non-stage 4 diseases (P = 0.0023), a single copy of N-myc (P = 0.027), and high levels of TRK-A expression (P = 0.0062). To examine the expression levels of GFR alpha-1, we cloned a short form of the human GFR alpha-1 gene with a 15-bp deletion by screening a human adult substantia nigra cDNA library. Many primary neuroblastomas expressed c-Ret, GFR alpha-1, and GFR alpha-2 as well as their ligands, GDNF and NTN, suggesting the presence of a paracrine or autocrine signaling system within the tumor tissue. The effect of NTN on primary culture cells of neuroblastoma was similar to that of GDNF. These imply that the GDNF(NTN)/c-Ret/GFR alpha-1(GFR alpha-2) signaling may have an important role in regulating the growth, differentiation, and cell death of neuroblastomas.

p73 at chromosome 1p36.3 is lost in advanced stage neuroblastoma but its mutation is infrequent.

p73, a novel p53 family member, is a recently identified candidate neuroblastoma (NBL) suppressor gene mapped at chromosome 1p36.33 and was found to inhibit growth and induce apoptosis in cell lines. To test the hypothesis that p73 is a NBL suppressor gene, we analysed the p73 gene in primary human NBLs. Loss of heterozygosity (LOH) for p73 was observed in 19% (28/151) of informative cases which included 92 mass-screening (MS) tumors. The high frequency of p73 LOH was significantly associated with sporadic NBLs (9% vs 34%, P<0.001), N-myc amplification (10% vs 71%, P<0.001), and advanced stage (14% vs 28%, P<0.05). Both p73alpha and p73beta transcripts were detectable in only 46 of 134 (34%) NBLs at low levels by RT-PCR methods, while they were easily detectable in most breast cancers and colorectal cancers under the same conditions. They found no correlation between p73 LOH and its expression levels (P>0.1). We found two mutations out of 140 NBLs, one somatic and one germline, which result in amino acid substitutions in the C-terminal region of p73 which may affect transactivation functions, though, in the same tumor samples, no mutation of the p53 gene was observed as reported previously. These results suggest that allelic loss of the p73 gene may be a later event in NBL tumorigenesis. However, p73 is infrequently mutated in primary NBLs and may hardly function as a tumor suppressor in a classic Knudson's manner.

Identification and purification of Ca2+/calmodulin-dependent protein kinase V from human gastric carcinoma.

We previously purified a novel Ca2+/calmodulin-dependent protein kinase (CaM kinase) V, which has proven to be a member of the CaM kinase I family. Immunohistochemical staining of surgically-resected specimens from human subjects using specific antibody which reacts with CaM kinases I and V demonstrated heterogeneous distribution of CaM kinase I/V in normal gastric mucosa. The kinase was located mainly at the bottom of foveoral epithelium and in the gastric gland (< 25% immunopositive). In contrast, this kinase was abundant in various types of gastric carcinomas (> 75%), but not in gastric adenomas. Preferential and consistent presence of this kinase was confirmed by immunoblot analysis of gastric carcinoma and human gastric cancer cell lines, Kato-III and MKN-45. CaM kinase I/V was co-purified with CaM kinase II from resected gastric carcinoma using anion-exchange chromatography followed by calmodulin-affinity chromatography. The two kinases were finally separated by HPLC-based gel filtration. Purified CaM kinase I/V from gastric carcinoma did not possess detectable autophosphorylating activity, in contrast to CaM kinase II. The findings suggest CaM kinase I/V may possess abnormal biochemical properties in human gastric carcinoma, and the kinase could participate in cell growth of the carcinoma.

Isolation and characterization of a novel human gene (NESH) which encodes a putative signaling molecule similar to e3B1 protein.

Using a conventional cloning technique, a novel full-length cDNA was isolated and sequenced from a human placental cDNA library. This cDNA consists of 2129 bp and has a predicted open reading frame encoding 366 amino acids. It possesses a Src homology 3 (SH3) motif, proline-rich region, serine-rich region and no catalytic domain, suggesting that it seems to be a signaling protein most similar to e3B1, an eps8 SH3 binding protein. PCR-based mapping with both a monochromosomal hybrid panel and radiation hybrid cell panels placed the gene to human chromosome 17q21.3 near the marker D17S1795.

Molecular cloning and characterization of a novel human gene (NESCA) which encodes a putative adapter protein containing SH3.

A full-length cDNA encoding a novel protein was isolated and sequenced from a human placental cDNA library. This cDNA consists of 1990 bp and has a predicted open reading frame encoding 433 amino acids. It possesses an Src homology 3 (SH3) motif, a leucine zipper motif and no catalytic domain, suggesting that it seems to be an adapter protein. PCR-based mapping with both a monochromosomal hybrid panel and radiation hybrid cell panels placed the gene to human chromosome 1q21-22.

Acetylcholine activates intracellular movement of insulin granules in pancreatic beta-cells via inositol trisphosphate-dependent [correction of triphosphate-dependent] mobilization of intracellular Ca2+.

Intracellular movement of secretory granules is a proximal stage in the secretory cascade that ends in the release product from cells. We investigated mechanisms underlying the control of this movement by acetylcholine using an insulinoma cell line, MIN6, in which acetylcholine increases both insulin secretion and granule movement. The peak activation of movement was observed 3 min after an acetylcholine challenge. The effects were nullified by the muscarinic inhibitor atropine, phospholipase C (PLC) inhibitors (D 609 and compound 48/80), and pretreatment with the Ca2+ pump inhibitor, thapsigargin. Inhibitors of Ca2+-dependent phospholipase A2 (arachidonyl trifluoromethyl ketone and methyl arachidonyl fluorophosphate) also partially inhibited the movement caused by acetylcholine, but downregulation of protein kinase C by overnight incubation with the phorbol ester 12-o-tetradecanoylphorbol-13-acetate failed to exert any influence. Acetylcholine stimulation of granule movement was not reproduced by membrane depolarization with high K+. Phosphorylation of the endogenous myosin light chain in MIN6 cells was increased by addition of acetylcholine and decreased by the Ca2+ chelator BAPTA (1,2-bis[2-aminophenoxy]ethane-N,N,N',N'-tetraacetic acid). The calmodulin inhibitor W-7 and the myosin light-chain kinase inhibitor ML-9 decreased the motile events in the beta-cells under both nonstimulated and acetylcholine-stimulated conditions. These findings led us to conclude that inositol trisphosphate [corrected] causes Ca2+ mobilization by muscarinic activation of PLC, leading to intracellular translocation of insulin granules to the ready-releasable pool in pancreatic beta-cells via Ca2+/calmodulin-dependent phosphorylation of myosin light chains.

Smoke-like echo in the left atrial cavity in mitral valve disease: its features and significance.

In some patients with mitral stenosis, a smoke-like echo is observed in the left atrial cavity. The present study in 116 consecutive patients with rheumatic mitral valve disease investigated the echocardiographic features and clinical significance of this echo. The smoke-like echo is characterized by the following echocardiographic features: 1) it is composed of numerous microechoes; 2) it curls up slowly in the enlarged left atrial cavity; and 3) it vanishes as soon as it pours into the ventricular cavity. Hemostasis in the left atrial cavity was considered to be an important underlying condition for development of the echo. Hemorheologic conditions indicated that the shear rate of blood flow in the left atrial cavity was calculated to be low enough for the development of red blood cell aggregation. These conditions suggest that the source of the smoke-like echo might be aggregated cells due to hemostasis in the left atrial cavity. Left atrial thrombi were detected in many patients who had this echo in the left atrial cavity. Although it has not been conclusively determined that the presence of the smoke-like echo is a necessary condition for thrombus formation, this echo appears to be closely related to thrombus formation in the left atrial cavity. It is concluded that the presence of this echo indicates severe left atrial hemostasis and is a warning for thrombus formation.