Continuous cyclosporine a infusion in patients with severe Kawasaki disease

BACKGROUND

The efficacy and safety of continuous intravenous infusion of cyclosporine A (CICsA) in patients with intravenous immunoglobulin-resistant Kawasaki disease are unclear.

METHODS

Between 2010 and 2020, 83 patients with Kawasaki disease that was not responsive to intravenous immunoglobulin (total dose ≥ 4 g/kg) were enrolled. All patients were started on CICsA (3 mg/kg/day) and switched to oral cyclosporine A (CsA) (4-6 mg/kg/day). Treatment efficacy, occurrence of coronary artery lesions (CALs), and laboratory parameters were evaluated. Patients were divided into two groups according to CICsA response: the responder group (afebrile ≤24 h after CICsA without additional treatment) and the weak responder group (afebrile >24 h after CICsA requiring additional treatment).

RESULTS

Fifty-five patients became afebrile within 24 and 74 h became afebrile in less than 72 h. Adverse events included hypertension in four and hyperkalemia in two patients. Thirty-nine patients were defined as responders and 44 patients as weak responders. There were no significant differences in CAL between the two groups. In weak responders, white blood cells, neutrophils, and C-reactive protein levels were higher, and albumin, immunoglobulin G, and CsA concentration were lower than in responders, indicating that weak responders had more severe inflammatory findings. However, there were no significant differences in CAL. Logistic regression analysis revealed that the response to treatment for CICsA was associated with immunoglobulin G levels at baseline and CsA concentrations the day after CICsA.

CONCLUSION

Although CICsA required additional treatments in about half of the cases, a favorable clinical course was observed by using this strategy, especially for reducing CAL.

Efficacy and safety associated with the infusion speed of intravenous immunoglobulin for the treatment of Kawasaki disease: a randomized controlled trial

BACKGROUND

High-dose intravenous immunoglobulin (IVIG) is the mainstay of treatment for Kawasaki disease (KD). Usually, 2 g/kg of IVIG is administered over 10-24 h, depending on the institution or physician, but the association between infusion speed and effectiveness has not been reported. In this study, we evaluated the differences in efficacy and safety between two different IVIG administration speeds.

METHODS

This was a multicenter, unblinded, randomized controlled study. Patients newly diagnosed with KD were randomized into two groups: one who received IVIG over 12 h (12H group, double speed), and one that received IVIG over 24 h (24H group, reference speed). The endpoints included the duration of fever, incidence of coronary artery abnormalities (CAAs) and of adverse events. Laboratory data were evaluated before and after IVIG administration.

RESULTS

A total of 39 patients were enrolled. There was no difference between groups in fever duration after the initiation of IVIG (21 h vs. 21.5 h, p = 0.325), and no patient experienced CAAs. Two adverse events were observed in the 12H group (elevation of aspartate aminotransferase and vomiting), however no severe adverse events requiring treatments or extension of hospital stay were observed in either group. After initial IVIG administration, the change ratio of inflammatory markers, such as white blood cell counts, neutrophils, C-reactive protein, and albumin, did not show significant differences between the two groups. On the other hand, a greater increase of serum immunoglobulin G from its baseline level was observed in the 24H group compared to the 12H group (3037 ± 648 mg/dl vs. 2414 ± 248 mg/dl, p < 0.01).

CONCLUSION

The efficacy and safety of IVIG administered over 12 h (double speed) were similar to those administered over 24 h (reference speed).

TRIAL REGISTRATION

University Hospital Medical Information Network ( UMIN000014665 ). Registered 27 July 2014 - Prospectively registered, https://upload.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno=R000017058.

Gene polymorphisms in antioxidant enzymes correlate with the efficacy of androgen-deprivation therapy for prostate cancer with implications of oxidative stress

Background

Oxidative stress mitigated by antioxidant enzymes is thought to be involved in the progression to castration-resistant prostate cancer (CRPC) during androgen-deprivation therapy (ADT). This study investigated the association between genetic variations in antioxidant enzymes and the efficacy of ADT as well as its biological background.

Patients and methods

The non-synonymous or promoter-locating polymorphisms of antioxidant enzymes were examined as well as the time to CRPC progression and overall survival in 104 and 92 patients treated with ADT for metastatic and non-metastatic prostate cancer, respectively. In addition, intracellular reactive oxygen species and expression levels of antioxidant enzymes were examined in castration-resistant and enzalutamide-resistant cells.

Results

In metastatic prostate cancer, the AG/GG allele in GSTM3 rs7483 and CT/TT allele in CAT rs564250 were associated with a significantly lower risk of progression to CRPC and all-cause death compared with homozygotes of the major AA allele (hazard ratio [HR]; [95% confidence interval (CI)], 0.55 [0.34-0.86], P = 0.0086) and CC allele (HR; [95% CI], 0.48 [0.24-0.88], P = 0.016), respectively. On multivariate analyses, only GSTM3 rs7483 was associated with significant progression risk (AG/GG versus AA; HR; [95% CI], 0.45 [0.25-0.79], P = 0.0047) even after Bonferroni adjustment. In non-metastatic prostate cancer, the AG/GG allele in GSTM3 rs7483 was associated with a significantly lower risk of progression to CRPC (HR; [95% CI], 0.35 [0.10-0.93], P = 0.034) and all-cause death (HR; [95% CI], 0.26 [0.041-0.96], P = 0.043) compared with the AA allele. Intracellular reactive oxygen species levels were increased, accompanied with augmented GSTM3 expression in both castration-resistant and enzalutamide-resistant cells.

Conclusions

Differential activity of antioxidant enzymes caused by the polymorphism in GSTM3 may contribute to resistance to hormonal therapy through oxidative stress. The GSTM3 rs7483 polymorphism may be a promising biomarker for prostate cancer patients treated with ADT.

Xq26.1-26.3 duplication including MOSPD1 and GPC3 identified in boy with short stature and double outlet right ventricle

Xq25q26 duplication syndrome has been reported in individuals with clinical features such as short stature, intellectual disability, syndromic facial appearance, small hands and feet, and genital abnormalities. The symptoms are related to critical chromosome regions including Xq26.1-26.3. In this particular syndrome, no patient with congenital heart disease was previously reported. Here, we report a 6-year-old boy with typical symptoms of Xq25q26 duplication syndrome and double outlet right ventricle (DORV) with pulmonary atresia (PA). He had the common duplicated region of Xq25q26 duplication syndrome extending to the distal region including the MOSPD1 locus. MOSPD1 regulates transforming growth factor beta (TGFβ) 2,3 and may be responsible for cardiac development including DORV. In the patient's lymphocytes, mRNA expression of TGFβ2 was lower than control, and might cause DORV as it does in TGFβ2-deficient mice. Therefore, MOSPD1 is a possible candidate gene for DORV, probably in combination with GPC3. Further studies of the combined functions of MOSPD1 and GPC3 are needed, and identification of additional patients with MOSPD1 and GPC3 duplication should be pursued.

[Tetralogy of Fallow with Total Anomalous Pulmonary Vein Return and Atrial Septal Defect;Successful Two-staged Surgical Management;Report of a Case]

A combination of tetralogy of Fallot( TOF) and total anomalous pulmonary venous return(TAPVR) is rare and results in chronic volume and pressure load of the right side of the heart and underfilling of the left heart. We report a successful 2-staged surgical correction of TOF associated with TAPVR and atrial septal defect. The patient was unsuitable for total primary intracardiac correction because the volume of the left ventricle was considered to be small. First, repair of anomalous pulmonary venous return and palliative right ventricle outflow tract reconstruction were simultaneously performed in 2 months of birth. One year after 1st operation, cardiac catheterization revealed that normalization of left ventricle volume, so 2nd operation was planned. Total correction of ventricular septal defect and right ventricle outflow reconstruction was performed and the patient was discharged on the 21st postoperative day with good hemodynamic status.

Epigenetic modulation at the CCR2 gene correlates with the maintenance of behavioral sensitization to methamphetamine

The intermittent administration of methamphetamine produces behavioral sensitization to methamphetamine. In the limbic forebrain, mainly including the nucleus accumbens, of mice that had been intermittently treated with methamphetamine, we found a significant increase in mRNA of a chemokine, CCR2. This increase was accompanied by a significant increase in histone H3 lysine 4 (H3K4) trimethylation at its promoter. Interestingly, the maintenance of sensitization to methamphetamine-induced hyperlocomotion was significantly decreased in CCR2 knockout mice. These findings suggest that increased CCR2 associated with epigenetic modification after the intermittent administration of methamphetamine may be associated with the maintenance of sensitization to methamphetamine-induced hyperlocomotion.

Human heterochromatin protein 1 isoform HP1beta enhances androgen receptor activity and is implicated in prostate cancer growth

There are currently few successful therapies for castration-resistant prostate cancer (CRPC). CRPC is thought to result from augmented activation of the androgen/androgen receptor (AR) signaling pathway, which could be enhanced by AR cofactors. In this study, heterochromatin protein 1beta (HP1beta), but not HP1alpha or HP1gamma was found to be an AR cofactor. HP1beta interacted with the AR, and enhanced the DNA-binding ability of AR to androgen-responsive element in the prostate-specific antigen enhancer and promoter regions, and to increase the transcription of AR target genes. In prostate cancer (PCa) tissues, HP1beta expressions correlated with Gleason score and tri-methylation levels of histone H3 lysine 9. Silencing of HP1beta suppressed the growth of AR-expressing PCa cells by inducing cell-cycle arrest at the G(1) phase, similar to inhibition of androgen/AR signaling. Furthermore, HP1beta was overexpressed in castration-resistant LNCaP derivative CxR cells, and HP1beta knockdown also suppressed the cell growth in CxR cells. These findings indicate that HP1beta is involved in the proliferation of AR-expressing PCa cells and progression to CRPC as an AR coactivator. Modulation of HP1beta expression or function might be a useful strategy for developing novel therapeutics for PCa, even in CRPC.

Molecular analysis of mechanisms regulating drug sensitivity and the development of new chemotherapy strategies for genitourinary carcinomas

The emergence of drug-resistant tumors during treatment remains one of the major obstacles in cancer chemotherapy. Overexpression of P-glycoprotein encoded by the multidrug resistance 1 (MDR1) gene or multidrug resistance-associated protein (MRP) (or both) and decreased expression of DNA topoisomerase II are responsible for expression of the multidrug resistance (MDR) phenotype. The expression of P-glycoprotein is also often observed in untreated cancers showing spontaneous MDR, such as renal cell carcinoma. Regarding cisplatin resistance, decreased cisplatin accumulation, an increase in cisplatin detoxification by glutathione-related enzymes or metallothionein (or both), and increased repair of DNA damage are all considered to play an important role. The combination of reversal agents targeting such drug resistance markers may be a way to improve the outcome of chemotherapy. Regarding the presently available reversal agents, however, clinically relevant chemosensitizing doses cannot be given to humans without inducing significant toxicity. The development of new agents that reverse drug resistance without causing significant toxicity and their clinical application based on the mechanisms regulating drug sensitivity may therefore be a potentially effective new treatment strategy for genitourinary carcinomas.

Human acid ceramidase is overexpressed but not mutated in prostate cancer

The human acid ceramidase gene, that causes Farber disease, is located in 8p22, a region frequently altered in several cancers, including prostate cancer. Acid ceramidase catalyzes the hydrolysis of ceramide, a potent lipid second messenger molecule that promotes apoptosis and inhibits cellular proliferation. It is not known whether this gene, or its expression, is altered in prostate cancer. Here, we report the structural organization of the human gene, its expression in human tissues, and the identification of several single nucleotide polymorphisms. No cancer-related mutations were found in the gene in a panel of prostate tumor DNAs analyzed, but increased expression was observed in prostate tumor tissues when compared with matched normals. This increase was observed in all three prostate tumor cell lines tested (DU145, LnCAP, and PC3) when compared to a BPH (benign prostatic hyperplasia) cell line and 15/36 prostate tumors. These results suggest that acid ceramidase may play an important role in prostate carcinogenesis.

Hand assisted laparoscopic radical nephrectomy for renal carcinoma using a new abdominal wall sealing device

PURPOSE

We report our initial experience with a hand assisted laparoscopic radical nephrectomy for patients with renal carcinoma, and compare our results to those of conventional open radical nephrectomy.

MATERIALS AND METHODS

The clinical data on 6 consecutive patients who underwent hand assisted laparoscopic radical nephrectomy for stage T1N0M0 renal cell carcinoma were reviewed. We performed hand assisted laparoscopic surgery using the new LAP DISC* abdominal wall sealing device. We compared the results of this procedure with those of conventional open radical nephrectomy in 12 patients with stage T1N0M0 renal cell carcinoma.

RESULTS

The hand assisted laparoscopic radical nephrectomy for renal carcinoma was successfully performed without any major or minor complications in all 6 patients. Mean operation time for the laparoscopic group was significantly longer than that for the open surgery group (303 minutes versus 224 minutes, p = 0.0042). However, no significant difference was observed in mean estimated blood loss for the 2 groups (264 ml. in the laparoscopic group versus 341 ml. in the open surgery group). The frequency of parenteral analgesia postoperatively in the laparoscopic group was significantly lower than that in the open surgery group (16.7% versus 75.0%, p = 0.043). In addition, the laparoscopic group seemed to recover more rapidly than the open surgery group. The abdominal wall sealing device was easy to attach to the abdominal wall, and allowed rapid hand removal and reinsertion.

CONCLUSIONS

Our preliminary results indicate that a hand assisted laparoscopic radical nephrectomy with the abdominal wall sealing device is an effective and safe surgical procedure, and is less invasive than open radical nephrectomy.

FHIT and TSG101 in thyroid tumours: aberrant transcripts reflect rare abnormal RNA processing events of uncertain pathogenetic or clinical significance

OBJECTIVE

The chromosomal regions containing the two putative tumour suppressors, fragile histidine triad gene (FHIT) and tumour suppressor gene 101 (TSG101), are deleted frequently in thyroid tumours. We therefore analysed FHIT and TSG101 transcripts in a group of advanced thyroid tumours to establish their role in thyroid tumorigenesis.

DESIGN

Retrospective analysis of FHIT and TSG101 mRNA transcripts and genomic DNA from cryo-preserved thyroid tumours. TP53, previously shown at the genomic level not to be mutated in this cohort of tumours, served as a control.

PATIENTS

We analysed nine follicular thyroid carcinomas (FTC), six papillary thyroid carcinomas and six follicular adenomas (FA) and histologically normal thyroid tissue from four of the FA patients.

MEASUREMENTS

Single stage and nested reverse transcription polymerase chain reaction (RT-PCR) products of FHIT, TSG101, and TP53 were analysed by agarose or polyacrylamide gel electrophoresis and sequenced. Genomic DNA was also analysed by polymerase chain reaction and sequencing (FHIT) or by Southern blotting (TSG101). Clinical data were correlated with the results of the mutation analysis.

RESULTS

Truncated FHIT transcripts were observed frequently alongside full length transcripts with nested RT-PCR, most often in FTC, while single stage RT-PCR revealed only normal length transcripts in all tumours. Similar results were obtained for TP53, while abnormal TSG101 transcripts were detectable by single stage RT-PCR. Sequence analysis of the truncated FHIT and TSG101 transcripts revealed mainly exon skipping and alternate RNA processing events. Only a single point mutation (of TSG101) was found. Southern blotting for the TSG101 gene, and PCR amplification and sequencing of the FHIT gene showed no evidence of genomic abnormalities in either case, and there was no evidence of splice site mutations in the FHIT gene, suggesting that the truncated transcripts result from altered RNA processing. There was no relationship between tumour stage, grade or survival and the presence of FHIT or TSG101 abnormalities.

CONCLUSIONS

Truncated FHIT and TSG101 transcripts in thyroid tumours reflect alternate mRNA splicing events, rather than genomic deletions. Such abnormal RNA processing seems to be common and widespread in thyroid neoplasms, as similar results were obtained by analysis of transcripts of TP53, which we had previously shown not to be mutated in these specimens. Although a pathogenetic role for these aberrant transcripts remains possible, no correlation was found with stage, histological grade or outcome in this small group of advanced thyroid malignancies. Relaxation of mRNA splice control appears to be a feature of follicular cell-derived thyroid neoplasms.

Accumulation of intracellular platinum is correlated with intrinsic cisplatin resistance in human bladder cancer cell lines

We investigated the mechanism of intrinsic resistance to cisplatin in human transitional cell cancer (TCC) using 7 human bladder cancer cell lines, which were derived from untreated TCC of the urinary bladder. The sensitivity to cisplatin was different from cell line to cell line, and a 15-fold difference was observed between the most sensitive line and the most resistant line. No significant correlation was observed between the content of intracellular glutathione and the resistance to cisplatin. In contrast, a positive correlation was seen between intracellular cisplatin accumulation and cisplatin resistance. The expression of drug resistance-related genes including glutathione S-transferase pi, gamma-glutamyl-cysteine synthetase, multidrug resistance-1, multidrug resistance-associated protein, DNA topoisomerase I, topoisomerase II, human canalicular multispecific organic anion transporter, and thioredoxin was not significantly related to cisplatin resistance. These data suggest that intracellular cisplatin may contribute to intrinsic cisplatin resistance and may therefore be a useful biomarker to predict cisplatin sensitivity in human untreated TCC.

Differential expression and allelotyping of the p73 gene in neuroblastoma

p73 has recently been identified as a candidate imprinted tumor suppressor gene in neuroblastoma. To determine the possible involvement of this gene in the pathogenesis of neuroblastoma, we analyzed allelic expression, screened for mutations and determined MYCN copy numbers in 31 primary neuroblastoma tumor samples. Interestingly, the gene was biallelically expressed in 50% (4/8) of informative neuroblastomas, which suggests that activation of the normally silenced allele of this gene plays an important role in the tumorigenesis of neuroblastoma. However, no tumor-specific mutations were identified although 15 polymorphisms were detected in this gene. We also detected a very strong association between a C91T polymorphism and MYCN copy number in this tumor. The T allele was detected in 8/17 (47%) neuroblastomas without MYCN amplifications but not detected in cases with MYCN amplifications (0/14). The biological significance of this association, however, is unknown. Overall the data suggest that p73 may play an important role in the pathogenesis of neuroblastoma but that the true tumor suppressor gene localized to this area still remains to be identified.

Mechanisms of drug resistance in chemotherapy for urogenital carcinoma

Cancer chemotherapy is the principal approach for urogenital cancers. However, the acquisition of resistance to anticancer agents is a critical factor that limits the successful treatment of malignancies. The multidrug resistant (MDR) phenotype has been widely recognized in cancer chemotherapy in urogenital tumors and the mechanisms underlying MDR have also been extensively studied. One of the principle mechanisms in MDR is caused by the overexpression of P-glycoprotein (P-gp), encoded by the multidrug resistance gene (MDR1). It functions as an ATP-dependent active efflux pump of chemotherapeutic agents in human cancer cells. Recently, other drug resistance proteins, including multidrug resistance-associated protein (MRP1) and cMOAT (or MRP2), were also identified from multidrug resistant cells. A functional analysis of MRP1 has shown that MRP1 may have the potential to act as a transporter of glutathione conjugates, which has been known as a central detoxification pathway in anticancer agents. Furthermore, several other resistance-related proteins (e.g. glutathione S-transferase, metallothionein, thioredoxin, topoisomerase I, II, O6-alkylguanine-DNA methyltransferase, etc.) have been found to be up- or down-regulated in resistant cells and these molecules are believed to contribute to the resistant phenotype as well. Based on the molecular characteristics identified in MDR, several experimental and clinical approaches have been studied to overcome MDR. One of these strategies is to reverse MDR by using such P-gp inhibitors as verapamil and cyclosporine A. In this review, we summarize the recent advances in MDR-related molecules and clinical trials to circumvent MDR in urogenital carcinomas.

Synthesis of phenoxyacetic acid derivatives as highly potent antagonists of gastrin/cholecystokinin-B receptors. III

In order to improve the biological characteristics of DA-3934 (5), a novel gastrin/cholecystokinin (CCK)-B receptor antagonist, phenoxyacetic acid derivatives replacing the N-methyl-N-phenylcarbamoylmethyl moiety of 5 with various alkyl chains have been synthesized and their biological activity evaluated. The relationship between the structure of these compounds and their human gastrin receptor binding affinity showed that there should be the optimal size among the various N-alkyl chains. Also a significant increase in the receptor binding affinity was achieved by several compounds. Among those compounds, 2-[3-[3- [N-cyclohexylmethyl-N-[2-(N-methyl- N-phenylcarbamoylmethoxy)phenyl]carbamoylmethyl]ureido]pheny l]acetic acid (22c) and (+/-)-2-[3-[3-[N-[2-(N-methyl-N- phenylcarbamoylmethoxy)phenyl]-N-(3-methylpentyl)carbamoy lmethyl]ureido] phenyl]acetic acid (22h) exhibited high affinity for human gastrin receptors and were also more potent inhibitors in a pentagastrin-induced gastric acid secretion model than the parent compound, 5. The ED50 values of these compounds when administered intraduodenally to rats were 0.12 and 0.63 mg/kg, respectively.

Mutation and expression analysis of the p73 gene in prostate cancer

BACKGROUND

p53 is the most highly mutated tumor suppressor gene in human cancers. Recently, p73, a first homologue of p53, was identified and considered to be an imprinted tumor suppressor gene. Thus, we analyzed the possible role of p73 in human prostate cancers.

METHODS

We investigated the expression levels and expressed allelotypes and searched for mutations in the p73 gene in 27 primary prostate cancers with matched normal tissues as well as in four prostate cell lines.

RESULTS

Allelic expression analysis using polymorphisms in exons 2 and 5 revealed that p73 is biallelically expressed in both normal and tumor tissues, suggesting that p73 is not imprinted in prostate tissues. Quantitative PCR demonstrated that p73 expression is the same in both normal and tumor prostate tissues. Denaturing high-performance liquid chromatography and DNA sequencing revealed that there were no tumor-specific mutations in the p73 gene at the genomic level.

CONCLUSIONS

These data indicate that alterations of p73, including mutations, changes in message abundance, and changes in allelic expression, are likely to be rare in early-stage prostate cancer, and that p73 could be a tissue-specific imprinting gene.

Overexpression of the wild type p73 gene in human bladder cancer

p73, a first p53 relative, was recently identified and shown to be monoallelically expressed in a number of different human tissues. To determine the potential role of this gene in human bladder cancer, we investigated p73 expression levels, allelic expression patterns, and analysed p73 mutations in 23 unselected primary invasive bladder cancers with matched normal tissues and in seven bladder cancer cell lines. In a comparison between normal and tumor tissues using quantitative RT-PCR analysis, we found that p73 was overexpressed in 22/23 bladder cancers, sometimes as great as 20-fold. Allelic expression analysis using a C/T polymorphism in exon 2 and a newly identified T/C polymorphism in exon 5 revealed that p73 was biallelically expressed in both normal bladder and cancer tissues, suggesting that p73 is not imprinted in bladder tissue. Mutation screening of the p73 gene in bladder cancer DNAs using denaturing high-performance liquid chromatography analysis and DNA sequencing revealed no tumor-specific mutations in any coding exons of the p73 gene. These data suggest that the p73 is unlikely to be a tumor suppressor gene, but that overexpression of p73 may contribute to tumorigenesis in bladder cancer.

Cloning of the human homolog of conductin (AXIN2), a gene mapping to chromosome 17q23-q24

Conductin or Axil, an Axin homolog, plays an important role in the regulation of beta-catenin stability in the Wnt signaling pathway. To facilitate the molecular analysis of the human gene, we isolated the human homolog, AXIN2. The cDNA contains a 2529-bp open reading frame and encodes a putative protein of 843 amino acids. Compared with rat and mouse homologs, AXIN2 shows an overall 89% amino acid identity. Several functional domains in this protein are highly conserved including the GRS (95.9%), GSK-3beta (96.3%), Dsh (98%), and beta-catenin (89.9%) domains. Radiation hybrid mapping localized the AXIN2 gene to human chromosome 17q23-q24, a region that shows frequent loss of heterozygosity in breast cancer, neuroblastoma, and other tumors. Human AXIN2 is thus a very strong candidate involved in multiple tumor types.

Loss of imprinting and allele switching of p73 in renal cell carcinoma

p73, a protein that has substantial structural and functional similarity to p53, has recently been identified. It was found to be monoallelically expressed in all cell lines and normal individuals tested. To elucidate its role in cancer development and as a potential imprinted tumor suppressor, we investigated the allele-specific expression of the human p73 gene in 28 cases of renal cell carcinoma and its imprinting status in fetal pancreatic and thymic tissues. Of 12 informative pairs of renal cell carcinoma and matched normal tissues identified by StyI restriction fragment length polymorphism (RFLP) in exon 2, p73 showed monoallelic expression in 11 out of 12 normal tissues but biallelic expression in 8/12 and switched allele expression in 2/12 of the matched corresponding cancers. An imprinting study of the p73 gene in two families using a newly identified exonic BanI RFLP indicated that expression of p73 was limited to the maternal allele in RNA from fetal pancreas and thymus, demonstrating that p73 is imprinted in at least these two tissues. These findings strongly suggest that loss of imprinting or switching of allelic expression of the p73 gene is associated with the development of renal cell carcinoma.

PTEN/MMAC1 mutations identified in small cell, but not in non-small cell lung cancers

A putative tumor suppressor, PTEN/MMAC1 gene at 10q23 was recently identified and found to be mutated in many different human tumors. To determine the role of the PTEN/MMAC1 gene in lung cancer, we screened 34 small cell lung cancer (SCLC) cell lines, 10 SCLC tumors, 13 non-small cell lung cancer (NSCLC) cell lines and 10 NSCLC tumors using Denaturing HPLC (DHPLC) and direct sequencing methods. In SCLC, six (18%) of the cell lines and one of the primary tumor samples (10%) showed alterations of the PTEN/MMAC1 gene including point mutations, small fragment deletions, and homozygous deletions. All of the point mutations and small fragment deletions were observed in hemizygously deleted cell lines. In contrast to SCLC, none of the NSCLC tumors or cell lines had mutations in the PTEN/MMAC1 gene. These data indicate that PTEN/MMAC1 mutations contribute to the pathogenesis and neoplastic evolution in SCLC but not in NSCLC.

Mutation analysis of the putative tumor suppressor PTEN/MMAC1 in human ovarian cancer

A putative tumor suppressor, PTEN/MMAC1 gene was recently identified at 10q23 and was found to be frequently altered in several types of human tumors. To determine the possible role of this gene in human ovarian tumors, we screened 31 unselected primary epithelial ovarian cancers with matched normal tissues and 7 ovarian cancer cell lines. Two homozygous deletions (4.8%) were detected in primary ovarian tumors by a semi-quantitative multiplex polymerase chain reaction. However, no point mutations were observed in any of the PTEN/MMAC1 coding sequences as determined by denaturing high-performance liquid chromatography and DNA sequencing. These data indicate that PTEN/MMAC1 mutations are rare in ovarian cancers.

Activation of p73 silent allele in lung cancer

p73, a first p53 relative, has recently been identified and demonstrated to be monoallelically expressed. This protein shows significant amino acid sequence and functional similarities to p53. However, it is unclear whether this protein functions as a tumor suppressor. To elucidate the role of p73 in tumor development, we investigated the expression of the p73 gene in lung cancer. In a comparison between normal lung and tumor tissues, p73 was more highly expressed in tumors. Moreover, using a C/T polymorphism in exon 2 for allele-specific expression analysis in 21 pairs of lung tumors and matched normal tissues, we found that five heterozygous samples exclusively expressed both alleles in tumors while showing monoallelic expression in matched normal tissues. This result was confirmed by single-nucleotide primer extension analysis. Mutation analysis of all 13 coding exons of the gene in 21 lung tumor DNAs revealed several polymorphisms, but no tumor-specific mutations were detected. These findings strongly suggest that p73 may play an important role in lung tumorigenesis through activation of a silent allele and overexpression of wild-type p73 rather than as a tumor suppressor.

Synthesis of phenoxyacetic acid derivatives as highly potent antagonists of gastrin/cholecystokinin-B receptors. II

A series of phenoxyacetanilide derivatives was synthesized and their antagonist activities for human gastrin/cholecystokinin (CCK)-B and CCK-A receptors were evaluated. Among the compounds synthesized, 2-[3-[3-[N-[2-(N-methyl-N-phenylcarbamoylmethoxy)phenyl]-N-(N-meth yl-N- phenylcarbamoylmethyl)carbamoylmethyl]-ureido]phenyl]acetic acid (20i, DA-3934) exhibited high affinity for gastrin/CCK-B receptors and high selectivity over CCK-A receptors. DA-3934 and its methyl ester derivative inhibited pentagastrin-induced gastric acid secretion in rats in a dose-dependent manner.

Synthesis of phenoxyacetic acid derivatives as highly potent antagonists of gastrin/cholecystokinin-B receptors

A novel series of phenoxyacetic acid derivatives was synthesized based on considerations of the three-dimensional structural similarity of YM022 and RP72540. The gastrin/cholecystokinin (CCK)-B and CCK-A receptor antagonist activities of these compounds were evaluated by investigation of their affinities for human gastrin/CCK-B receptors and human CCK-A receptors, respectively. It was found that N-methyl-N-phenyl-2-[2-[N-(N-methyl-N-phenyl-carbamoylmethyl)-N-[2 -[3-(3- methylphenyl)ureido]acetyl]amino]phenoxy]acetamide (20k, DZ-3514) exhibited high affinity for gastrin/CCK-B receptors and high selectivity over CCK-A receptors.

The close association of pi-class glutathione S-transferase with drug sensitivity to alkylating agents and cisplatin in human cancer cells

Buthionine sulfoximine (BSO) is a synthetic amino acid that irreversibly inhibits glutathione biosynthesis. A BSO-resistant line, KB/BSO3, was established from human epidermoid cancer KB cells; and other BSO-resistant lines, HLE/BSO1 and HLE/BSO2, were from human hepatic cancer HLE cells. Cellular level of pi-class glutathione S-transferase (GSTP1) in KB/BSO3 was less than 10% of the parental KB, and those in HLE/BSO1 and HLE/BSO2 wa 30-40% of the parental HLE cells. KB/BSO3, HLE/BSO1 and HLE/BSO2 had collateral sensitivities to a potent anticancer agent, cisplatin, and alkylating agents including melphalan and nitrosourea. The GSTP1 cDNA transfectant KB/BSO3-pi established from KB/BSO3, and also HLE/BSO1-pi and HLE/BSO2-pi established from HLE/BSO1 and HLE/BSO2, restored cellular sensitivities to cisplatin and alkylating agents to similar levels as KB and HLE cells. Our present results indicate that GSTP1 levels apparently limit cellular sensitivities to cisplatin and alkylating agents, suggesting that GSTP1 is a useful diagnostic marker for drug sensitivities to these agents in human cancer cells.

Enhanced expression of gamma-glutamylcysteine synthetase and glutathione S-transferase genes in cisplatin-resistant bladder cancer cells with multidrug resistance phenotype

PURPOSE

To elucidate the mechanisms of cisplatin resistance in human bladder cancer.

MATERIALS AND METHODS

After continuous exposure of KK47 cells to cisplatin, two resistant sublines, KK47/DDP10 and KK47/DDP20 were established. The glutathione content, glutathione S-transferase activity, and intracellular platinum concentration were measured while the expression of various drug resistance-related genes was examined.

RESULTS

KK47/DDP10 and KK47/DDP20 were respectively 9.3- and 18.7-fold more resistant to cisplatin than KK47, and also showed multidrug resistance. Decreased intracellular drug accumulation, increased glutathione content, elevated glutathione S-transferase activity, and an overexpression of gamma-glutamylcysteine synthetase and glutathione S-transferase pi genes were observed in the resistant sublines.

CONCLUSIONS

Multiple mechanisms, including decreased drug accumulation, increased intracellular glutathione and glutathione S-transferase pi, may contribute to the acquisition of cisplatin resistance in human bladder cancer.

Enhanced coexpression of thioredoxin and high mobility group protein 1 genes in human hepatocellular carcinoma and the possible association with decreased sensitivity to cisplatin

Thioredoxin (TRX), a disulfide-reducing intracellular protein, functions as a cellular defense mechanism against oxidative stress. In this study, we asked whether expression of TRX, glutathione-thiol transferase pi, and high mobility group protein 1 (HMG-1) genes is enhanced in human hepatocellular carcinoma and whether expression of these genes is associated with sensitivity to cisplatin. Both TRX and HMG-1 were co-overexpressed in almost all cancerous lesions in comparison to normal tissue in surgically resected hepatocellular carcinomas of 20 patients. Tumor sensitivity to cisplatin [cis-diamminedichloroplatinum (II)], but not to mitomycin C or doxorubicin, correlated with mRNA levels of TRX in cancer tissue. TRX and HMG-1 may be useful tumor markers, and TRX might be also a useful marker for sensitivity to cisplatin in human hepatocellular carcinomas.

Non-P-glycoprotein-mediated atypical multidrug resistance in a human bladder cancer cell line

A human bladder cancer cell line resistant to adriamycin (ADM), T24/ADM9 has been established in vitro by exposing T24 parent cells to progressively higher concentrations of the drug over a period of 12 months. The T24/ADM9 cells were found to be 9 times more resistant to ADM than the T24 parent, and showed various degrees of cross-resistance to an ADM derivative, vinea alkaloids and a DNA topoisomerase II (Topo II)-targeting agent, etoposide. No significant differences was observed in the cellular accumulation of ADM between the T24/ADM9 and T24 parent cells. A Northern blot analysis showed an overexpression of multidrug resistance-associated protein (MRP) mRNA, but no overexpression of multidrug resistance-1 (MDR1) mRNA was observed in the T24/ADM9 cells. A flow cytometric analysis showed that the MDR1 gene product, P-glycoprotein (Pgp), is not expressed on the T24/ADM9 cells. T24/ADM9 showed approximately the parental level of DNA Topo II catalytic activity. In Western blot and Northern blot analyses, however, the cellular level of DNA topo II was apparently much lower in T24/ADM9 than in the T24 parent. Thus, these results suggest that a decreased cellular level of DNA Topo II and an overexpression of MRP gene may be responsible for the expression of an MDR phenotype in the T24/ADM9 cells and that such non-Pgp-mediated, atypical MDR may develop in bladder cancer treated with chemotherapy including ADM.

Cellular levels of thioredoxin associated with drug sensitivity to cisplatin, mitomycin C, doxorubicin, and etoposide

Thioredoxin, a cellular thiol, functions as a self-defense mechanism in response to environmental stimuli, including oxidative stress. We first determined cellular levels of thioredoxin in several human bladder and prostatic cancer cell lines resistant to cis-diamminedichloroplatinum(II) (cisplatin). All cisplatin-resistant cell lines had much higher levels of thioredoxin than those in their drug-sensitive parental counterpart. We then, by introducing thioredoxin antisense expression plasmids into human bladder cancer T24 cells, established two bladder cancer cell lines that had decreased levels of thioredoxin. These thioredoxin antisense transfectants showed increased sensitivity to cisplatin and also to other superoxide-generating agents, i.e., doxorubicin, mitomycin C, etoposide, and hydrogen peroxide, as well as to UV irradiation, but not to the tubulin-targeting agents, vincristine, and colchicine. Cellular levels of thioredoxin thus appear to limit sensitivity to various superoxide-generating anticancer drugs in cancer cells.

Markedly decreased expression of glutathione S-transferase pi gene in human cancer cell lines resistant to buthionine sulfoximine, an inhibitor of cellular glutathione synthesis

Buthionine sulfoximine (BSO) is a synthetic amino acid that irreversibly inhibits an enzyme, gamma-glutamylcysteine synthetase (gamma-GCS), which is a critical step in glutathione biosynthesis. We isolated three BSO-resistant sublines, KB/BSO1, KB/BSO2, and KB/BSO3, from human epidermoid cancer KB cells. These cell lines showed 10-to 13-fold higher resistance to BSO, respectively, and had collateral sensitivity to cisplatin, ethacrynic acid, and alkylating agents such as melphalan and nitrosourea. Cellular levels of glutathione S-transferase pi (GST-pi) and its mRNA in BSO-resistant cell lines were less than 10% of the parental cells. Nuclear run-on assay showed that the transcriptional activity of GST-pi was decreased in BSO-resistant cells, and transient transfection of GST-pi promoter-chloramphenicol acetyltransferase constructs revealed that the sequences between -130 and -80 base pairs of the 5'-flanking region wer at least partially responsible for the decreased expression of the GST-pi gene. By contrast, gamma-GCS mRNA levels were 3-to 5-fold higher in resistant cell lines than in KB cells, and the gamma-GCS gene was found to be amplified in the BSO-resistant cells lines. GST-pi mRNA levels appeared to be inversely correlated with gamma-GCS mRNA levels in BSO-resistant cells. We further established the transfectants, KB/BSO3-pi1 and KB/ BSO2-pi2, that overexpressed GST-pi, from KB/BSO3, after introducing a GST-pi expression plasmid. These two transfectants had similar levels in gamma-GCS mRNA, drug sensitivity to alkylating agents, and glutathione content at those of KB cells. These findings suggest that the cellular levels of GST-pi and gamma-GCS might be co-regulated in these novel BSO-resistant cells.

Possible involvement of multidrug-resistance-associated protein (MRP) gene expression in spontaneous drug resistance to vincristine, etoposide and adriamycin in human glioma cells

The multidrug-resistance phenotype in human tumors is partly associated with over-expression of the 170 kDa-P-glycoprotein encoded by the multidrug-resistance-1 (MDR1) gene. Another related, but non-P-glycoprotein, multidrug-resistance-associated protein (MRP) gene encodes a 190 kDa-membrane ATP-binding protein. Glioblastoma multiforme is a highly malignant primary neoplasm of the central nervous system which is refractory to anti-cancer chemotherapy, but the mechanism underlying this drug resistance is unknown. Out of glioma cell lines, 2, namely IN500 and T98G, which had elevated MRP mRNA levels, showed the highest resistance to multiple anti-cancer agents such as etoposide, vincristine and adriamycin, and decreased intracellular accumulation of etoposide. In the remaining 5 cell lines, various degrees of sensitivity to adriamycin and etoposide appeared to correlate with their respective MRP mRNA levels. Our study proposes that MRP may be involved in spontaneous multidrug resistance in human gliomas.

[Atypical MDR]

Multiple drug resistance(MDR) is a major clinical obstacle in cancer chemotherapy. Acquirement of MDR phenotype in cancer cells is often associated with enhanced expression of human MDR-1 gene: MDR-1 gene codes membranous P-glycoprotein which catalyses energy-dependent outward transport of anticancer agents. By contrast, MDR cancer cell lines without overexpression of P-glycoprotein are called as atypical MDR (at MDR) cells. The acquirement of at MDR has been shown to be partly associated with altered DNA topoisomerase II. Furthermore, a new ATP binding cassette (ABC) family, MRP gene has just recently shown to involve in acquirement of at-MDR in cancer cell lines, which do not express both altered topoisomerase II and P-glycoprotein.

Increased expression of DNA topoisomerase I gene and collateral sensitivity to camptothecin in human cisplatin-resistant bladder cancer cells

We established three cis-diamminedichloroplatinum(II) (cisplatin)-resistant cell lines, T24/DDP5, T24/DDP7, and T24/DDP10, by the stepwise exposure of T24 human bladder cancer cells to increasing concentrations of cisplatin. The resistance to cisplatin of T24/DDP5, T24/DDP7, and T24/DDP10 cells was 2.2-, 5.2-, and 8.4-fold that of the parental T24 cells, respectively. The cisplatin-resistant cell lines also showed an increased resistance to vincristine, although their sensitivities to Adriamycin and etoposide resembled that of T24. In contrast, the cisplatin-resistant cells developed a collateral sensitivity to (4s)-4,11-diethyl-4-hydroxy-9-[(4-piperidinopiperidino)carbonyl oxy]dione hydrochloride trithydrate, a camptothecin derivative, and its active metabolite, 7-ethyl-10-hydroxy-camptothecin, that targets DNA topoisomerase I. Both a Northern blot analysis and an immunoblot analysis demonstrated increased cellular levels of DNA topoisomerase I mRNA in the resistant cell lines. However, the expression of DNA topoisomerase II in the three resistant cell lines did not differ significantly from that in the T24 cells. No significant differences in the glutathione S-transferase pi levels were observed, although the intracellular content of glutathione in the T24/DDP7 cells was slightly but significantly increased. In addition, the intracellular platinum concentration correlated negatively with the degree of cisplatin resistance and was found to be significantly decreased in T24/DDP10 at an external cisplatin concentration of 20 micrograms/ml. These results suggest that the increased levels of DNA topoisomerase I mRNA thus play an important role in cisplatin resistance and produce a collateral sensitivity to (4s)-4,11-diethyl-4-hydroxy-9[(4-piperidinopiperidino)carbonylo xy]dione hydrochloride trithydrate and 7-ethyl-10-hydroxycamptothecin in these cisplatin-resistant bladder cancer cell lines. In addition, the presence of decreased intracellular cisplatin accumulation may also contribute to the acquisition of resistance to cisplatin in these cell lines.