Integrated analysis of a competing endogenous RNA network reveals a ferroptosis-related 6-lncRNA prognostic signature in clear cell renal cell carcinoma

BACKGROUND

Establishing a robust signature for prognostic prediction and precision treatment is necessary due to the heterogeneous prognosis and treatment response of clear cell renal cell carcinoma (ccRCC).

OBJECTIVES

This study set out to elucidate the biological functions and prognostic role of ferroptosis-related long non-coding RNAs (lncRNAs) based on a synthetic analysis of competing endogenous RNA networks in ccRCC.

MATERIAL AND METHODS

Ferroptosis-related genes were obtained from the FerrDb database. The expression data and matched clinical information of lncRNAs, miRNAs and mRNAs from The Cancer Genome Atlas (TCGA) database were obtained to identify differentially expressed RNAs. The lncRNA-miRNA-mRNA ceRNA network was established utilizing the common miRNAs that were predicted in the RNAHybrid, StarBase and TargetScan databases. Then, using progressive univariate Cox regression, least absolute shrinkage and selection operator (LASSO) and multivariate Cox regression analysis of gene expression data and clinical information, a ferroptosis-related lncRNA prognosis signature was constructed based on the lncRNAs in ceRNA. Finally, the influence of independent lncRNAs on ccRCC was explored.

RESULTS

A total of 35 ferroptosis-related mRNAs, 356 lncRNAs and 132 miRNAs were sorted out after differential expression analysis in the TCGA-KIRC. Subsequently, overlapping lncRNA-miRNA and miRNA-mRNA interactions among the RNAHybrid, StarBase and TargetScan databases were constructed and identified; then a ceRNA network with 77 axes related to ferroptosis was established utilizing mutual miRNAs in 2 interaction networks as nodes. Next, a 6-ferroptosis-lncRNA signature including PVT1, CYTOR, MIAT, SNHG17, LINC00265, and LINC00894 was identified in the training set. Kaplan-Meier analysis, PCA, t-SNE analysis, risk score curve, and receiver operating characteristic (ROC) curve were performed to confirm the validity of the signature in the training set and verified in the validation set. Finally, single-sample gene set enrichment analysis (ssGSEA) and ESTIMATE (Estimation of STromal and Immune cells in MAlignant Tumor tissues using Expression data) analysis showed that the signature was related to immune cell infiltration.

CONCLUSIONS

Our research underlines the role of the 6-ferroptosis-lncRNA signature as a predictor of prognosis and a therapeutic alternative for ccRCC.

Liposome-coated nanoparticle triggers prostate cancer ferroptosis through synergetic chemodynamic-gas therapy

Ferroptosis has attracted much attention for tumor treatment. It has been recently identified that castration-resistant prostate cancer (CRPC) is vulnerable to ferroptosis inducers. Notably, chemodynamic therapy (CDT), triggered by metal ions, could easily induce ferroptosis via a Fenton/Fenton-like reaction, but its efficiency was highly dependent on the intracellular H2O2 concentration, posing significant changes for its clinical translation. Herein, we attached glucose oxidase (GOx) onto the surface of manganese sulfide (MnS) and developed therapeutic nanocomposites (Lpo@MnS-GOx) after encapsulating with liposome. Upon internalization by cancer cells, the released GOx could transform glucose into gluconic acid (GA) and H2O2. Notably, the generated GA stimulates the degradation of MnS, followed by the promotion of the release of H2S and Mn2+, whereas the produced H2O2 can amplify the Fenton-like response initiated by Mn2+. The enhanced CDT combined with the gas therapy effect could simultaneously promote the accumulation of reactive oxygen species and finally induce ferroptosis and exhibit an excellent anti-tumor effect. Consequently, these Lpo@MnS-GOx NPs with enhanced ferroptosis-induced effect will find great potential for CRPC cancer treatment.

Establishing a Risk Stratification Model to Identify Clinically High-Risk N0 Breast Cancer Who Could Benefit from Regional Nodal Irradiation: A Single Institute Analysis

PURPOSE/OBJECTIVE(S)

The adverse clinical features for pN0 BC patients significantly varies and there is no established clinical risk stratification system to identify those "high-risk" pN0 BC patients who might benefit from RNI. The purpose of this real-world study was to investigate the risk factors for developing recurrence among patients with pathological T1-3N0 breast cancer (BC) treated with breast-conserving surgery (BCS) followed by whole breast irradiation alone (WBI) and identify those clinically high-risk BCs who could benefit from regional nodal irradiation (RNI).

MATERIALS/METHODS

Female BC patients treated from 2009 to 2016 were retrospectively reviewed. The disease-free survival (DFS) and overall survival (OS) were estimated by the Kaplan-Meier method, and survival differences were compared with the log-rank test. Univariate and multivariate analysis was performed using Cox logistic regression analysis. An external validation was conducted by using SEER database.

RESULTS

A total of 622 BC patients treated with BCS+WBI alone were included. With a median follow-up of 82 months, the 7-year OS and DFS for the entire cohort was 97% and 91%, respectively. Multivariable Cox analysis indicated that tumor size (p = 0.006), tumor location (p = 0.033), lymphovascular invasion (LVI) status (p = 0.0028) and Ki-67 index (p = 0.051) were independent risk factors for DFS, while only tumor size was the only independent risk factors for OS (p = 0.029). A scoring system was developed using these four factors and the 7-year DFS and OS were 97% and 96% for patients with 0-1 risk factors, 95% and 82% for patients with ≥2 risk factors (p<0.0001 for DFS, and p = 0.0063 for OS). Based on tumor size and tumor location, an external validation by demonstrated that the 7-year OS was 90% and 88% for patients with 0-1 risk factor, which was significantly better than those defined as high-risk BC patients (82%, p<0.0001).

CONCLUSION

By using our institute database, we establish a risk stratification system for identifying sub-group of pN0 BC patients, who are at high risk for developing recurrence. The results of our study support tailored RT decision-making according to individual risks, which needed to be confirmed in further studies.

Treatment Outcomes and Prognostic Factors of Chemotherapy Combined with Radiotherapy for Patients with Stage I-II Nasal-Type Natural Killer/T-Cell Lymphoma

PURPOSE/OBJECTIVE(S)

The purpose of this study was to assess the treatment outcome and the potential prognostic factors for patients with stage I-II nasal ENKTL treated with radiotherapy (RT) combined chemotherapy (CT).

MATERIALS/METHODS

From July, 2005 to January, 2019, 118 eligible patients were retrospective included in the study. Among the 118 patients, 84 were male and 34 were female. The median age was 45 years (range: 14-77 years). According to the Ann Arbor staging system, 66 patients had stage I disease (Primary tumor invasion (PTI) was present in 29 patients), and 52 patients had stage II disease. B symptoms were observed in 61 patients. The Eastern Cooperative Oncology Group (ECOG) performance score was 0 to 1 in 88 patients. Cervical lymph node involvement was observed in 51 patients. The primary lesions were located in the nasal cavity in 92 cases and in the Waldeyer ring in 26 cases. Five patients had received RT followed by CT (RT + CT), 20 patients had received CT followed by RT (CT + RT), 90 patients had received CT followed by RT, again followed by CT (CT+RT+CT), and 3 patients had received concurrent chemoradiotherapy (CRT) (1 patient received CRT + CT, other 2 patients received CT+CRT+CT). Patients were irradiated with a median dose of 50 Gy (range, 24-61.2). All patients received chemotherapy, 91 received non-anthracycline-based chemotherapy, whereas 27 patients received anthracycline-based chemotherapy. The median number of courses of chemotherapy was four (range: 1-10). Patients were scored as having low-risk disease (n = 50), intermediate-risk disease (n = 60) or high-risk disease (n = 8) according to the prognostic index of natural killer cell lymphoma (PINK).

RESULTS

Among the 118 patients, after initial therapy, the complete response (CR) rate was 82.2% (n = 97), and the partial response (PR) rate was 11.0% (n = 13). The stable disease (SD) rate was 2.5% (n = 3), and the progressive disease (PD) rate was 4.2% (n = 5). With a median follow-up of 43 months (range, 4-201) after irradiation, the 3-year PFS and OS were 76.9% and 82.9%, respectively. The 3-year OS rate was 75.0% for RT + CT, 70.0% for CT + RT, 87.1% for CT + RT+ CT, and 50.0% for CRT (P = 0.052). Three-year OS and PFS were 88.6% and 83.4%, respectively, for non-anthracycline-based chemotherapy regimen compared to 61.6% (P = 0.001) and 58.4% (P = 0.003), respectively, for the anthracycline-based chemotherapy regimen. Three-year OS and PFS were 84.0% and 79.0%, respectively, for patients receiving high-dose RT (≥50 Gy, n = 111) compared to 71.4% (P = 0.076) and 71.4% (P = 0.228), respectively, for low-dose RT (<50 Gy, n = 7). In multivariate analysis, adverse factors associated with OS in our study were chemotherapy regimen and response to RT and CT (P = 0.047, <0.001).

CONCLUSION

Radiotherapy combined with chemotherapy reported promising response rate and a favorable survival for patients with stage I-II nasal ENKTL. Anthracycline-based chemotherapy regimen and no remission after RT and CT were adverse factors of OS.

Toripalimab Combined with Chemoradiotherapy for Locally Advanced Cervical Squamous Cell Carcinoma Patients: Early Results of Safety and Feasibility

PURPOSE/OBJECTIVE(S)

To assess the safety and efficacy of toripalimab combined with chemoradiotherapy for locally advanced cervical squamous cell carcinoma.

MATERIALS/METHODS

Twenty-two locally advanced cervical cancer patients, regardless of programmed death ligand-1 (PD-L1) status, received toripalimab treatment combined with concurrent chemoradiotherapy (CCRT), includes cisplatin (40 mg/m2, once a week for 5 weeks), radiotherapy (45-50.4 Gy/25-28Fx, 5 fractions a week, followed by brachytherapy 24-30 Gy/3-5Fx) and toripalimab (240mg on day 1, 22 and 43). The primary endpoints were safety and 2-year progression-free survival (PFS).

RESULTS

The median age was 55 years old (42 to 72), with 2 patients in FIGO stage Ⅱ, 15 patients in stage ⅢC, and 5 patients in stage ⅣA. All patients completed CCRT successfully. Grade Ⅲ and higher adverse events (AEs) were observed in 11 patients (11/22, 50%), and no patient had a grade Ⅴ AE. The most frequent grade Ⅲ AE was leukopenia (8/22, 36.4%). The most common immunotherapy-related adverse event was hypothyroidism (2/22, 9.1%). The objective response rate (ORR) was 100%. At data cutoff (Sep 30, 2022), the median follow-up was 19.7 months (7.67 to 26.1 months). The LC and the PFS rate were 95.5% and 81.8%, and the OS rate was 90.9%. The patients with baseline absolute lymphocyte count (ALC) ≤1.255 × 10^9/L had significant higher rates of metastasis than those with ALC >1.255 × 10^9/L (42.9% vs 0%, p = 0.023).

CONCLUSION

Toripalimab combined with CCRT achieved good tolerance and demonstrated promising anti-tumor effects in patients with locally advanced cervical cancer. Longer follow-up results and further phase Ⅱ/Ⅲ studies are expected. Chinese Clinical Trial Registry number, ChiCTR2000032879.

Integrated Analysis of a Competing Endogenous RNA Network Reveals a Ferroptosis-related 6-LncRNA Prognostic Signature in Clear Cell Renal Cell Carcinoma.. [DOI: 10.21203/rs.3.rs-2294111/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Background: This study set out to elucidate the biological functions and prognostic role of ferroptosis-related lncRNAs based on a synthetic analysis of competing endogenous RNA (ceRNA) networks in clear cell renal cell carcinoma (ccRCC). Methods: Ferroptosis-related genes were obtained from the FerrDb database. The expression data and matched clinical information of lncRNAs, miRNAs, and mRNAs from The Cancer Genome Atlas (TCGA) database were obtained to identify differentially expressed RNAs (DERNAs). The lncRNA-miRNA-mRNA ceRNA network was established utilizing the common miRNAs that were predicted in the RNAHybrid, StarBase, and TargetScan databases. Then, by progressive univariate Cox regression, LASSO,and multivariate Cox regression analysis of gene expression data and clinical information, a ferroptosis-related lncRNA prognosis signature was constructed based on the lncRNAs in ceRNA. Finally, the influence of independent lncRNAs on ccRCC was explored through a series of functional and unsupervised cluster analysis. Results: A total of 35 ferroptosis-related DEmRNAs, 356 DElncRNAs, and 132 DEmiRNAs were sorted out from the KIRC cohort of TCGA database. Overlapping DElncRNA-DEmiRNA and DEmiRNA-DEmRNA interactions among the RNAHybrid, StarBase, and TargetScan databases were constructed and identified, then a ceRNA network with 77 axes related to ferroptosis was established utilizing mutual DEmiRNAs in two interaction networks as nodes. Through synthetic analysis of the expression data and clinical information of 27 lncRNAs in the ceRNA network, a 6-ferroptosis-lncRNA signature including PVT1, CYTOR, MIAT, SNHG17, LINC00265, and LINC00894 was identified in the training set. Kaplan-Meier, PCA, t-SNE analysis, risk score curve, and ROC curve were performed to confirm the validity of the signature in the training set and secondly verified in the validation set. Finally, ssGSEA and ESTIMATE analysis showed that the signature was related with immune cell infiltration and could predict immune-related phenotypes. Conclusions: Our research underlines the role of the 6-ferroptosis-lncRNA signature as a predictor of prognosis and a therapeutic alternative for KIRC.

Identification of the Putative Tumor Suppressor Characteristics of FAM107A via Pan-Cancer Analysis

Family with sequence similarity 107, member A(FAM107A) was supposed as a tumor suppressor for various types of tumors. However, no pan-cancer analysis of FAM107A is available. Therefore, we conducted a FAM107A-related pan-cancer analysis across thirty-three tumors based on TCGA database to explore the molecular characteristics of FAM107A. The FAM107A expression is reduced in most cancers, and its down-regulated expression was linked to poor overall survival and progression-free survival of tumor patients. Analysis of DNA methylation of the FAM107A gene showed a negative correlation between FAM107A expression and promoter methylation in numerous cancers. Furthermore, FAM107A expression was noted to be involved in myeloid-derived suppressor cell infiltration in multiple cancers. To explore the mechanism of FAM107A in cancers, KEGG, and GO enrichment analysis was performed and the result showed "cell adhesion" and "cAMP signaling pathway" terms as the potential impact of FAM107A on cancers. An experiment in vitro showed FAM107A knockdown promoted the proliferation, migration, and invasion of bladder cancer and renal cancer cells. Our study indicates that FAM107A may be a putative tumor suppressor in bladder cancer and other tumors.

Identification of hsa_circ_0002024 as a prognostic competing endogenous RNA (ceRNA) through the hsa_miR_129-5p/Anti-Silencing Function 1B Histone Chaperone (ASF1B) axis in renal cell carcinoma

We aimed to identify novel circular RNAs (circRNAs) as prognostic competing endogenous RNAs (ceRNAs) to serve as genetic biomarkers and therapeutic targets for renal cell carcinoma (RCC). High-throughput sequencing data of circRNAs from Gene Expression Omnibus (GEO) and of microRNAs (miRNAs) and messenger RNAs (mRNAs) from The Cancer Genome Atlas (TCGA) were retrieved to identify differentially expressed RNAs (DERNAs). DEmRNAs were subjected to weighted gene coexpression network analysis (WGCNA) to identify prognostic DEmRNA (proDEmRNA) modules. Overlapping DEcircRNA-DEmiRNA and DEmiRNA-proDEmRNA interactions among the TargetScan, miRanda and RNAhybrid databases were constructed and identified. The circRNA-miRNA-mRNA ceRNA network was constructed using mutual DEmiRNAs in two interaction networks as nodes. mRNAs validated as significantly overexpressed in RCC by Oncomine, Gene Expression Profiling Interactive Analysis (GEPIA) and quantitative polymerase chain reaction (q-PCR), along with the correlative miRNAs, were used for survival analysis. Finally, a ceRNA network with 13 upregulated circRNAs, 8 downregulated miRNAs and 21 upregulated mRNAs was constructed, in which Anti-Silencing Function 1B Histone Chaperone (ASF1B) and Forkhead Box M1 (FOXM1) were considered significant by Oncomine, GEPIA and q-PCR. Survival analysis showed that ASF1B, FOXM1 and hsa_miR_1254 were significantly negatively correlated but hsa_miR_129-5p was positively correlated with overall survival time. Exploration of the ceRNA network revealed the prognostic hsa_circ_0002024/hsa_miR_129-5p/ASF1B axis. Therefore, hsa_circ_0002024 was identified as a prognostic ceRNA that might sponge hsa_miR_129-5p to regulate ASF1B and affect RCC prognosis. However, further validation is needed.

A novel ferroptosis-related 12-gene signature predicts clinical prognosis and reveals immune relevancy in clear cell renal cell carcinoma

BACKGROUND

Clear cell renal cell carcinoma (ccRCC) is still highly aggressive and lethal even with various therapeutic approaches. As the kidney is an iron metabolism-related organ, exploring and assessing the clinical value of ferroptosis, an iron-dependent regulated cell death, is practical and important.

METHODS

Prognostic ferroptosis-related differentially expressed genes (DEGs) were identified from the KIRC cohort in the cancer genome atlas (TCGA) database, from which a prognostic signature was established using Lasso-penalized Cox regression analysis. Each patient in the KIRC cohort and the E-MTAB-1980 cohort (from the ArrayExpress database) was assigned a calculated signature-correlated risk score and categorized to be either in the high- or low-risk group divided by the median risk score in the KIRC cohort. Then, the independent prognostic value of the signature was further assessed by Kaplan-Meier (K-M) survival, time-dependent receiver operating characteristic (ROC) and Cox regression analyses based on overall survival (OS) in both cohorts. Finally, risk-related DEGs were identified in both cohorts and subjected to enrichment analyses for Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) and immune infiltration.

RESULTS

Among 60 ferroptosis-related genes, 32 prognostic DEGs were identified, from which we constructed a prognostic 12-gene signature with CARS1, HMGCR, CHAC1, GOT1, CD44, STEAP3, AKR1C1, CBS, DPP4, FANCD2, SLC1A5 and NCOA4. Patients in both cohorts were divided into high- and low-risk groups, which were visually distributed in two sets and had positive-risk-related mortality. The K-M survival and the ROC curves validated that the signature has prognostic value with P < 0.05 and area under the curve > 0.7 in both cohorts, respectively. Multivariate Cox regression further confirmed the risk score as an independent prognostic predictor for OS. Commonly enriched terms in GO and KEGG not only showed a high iron correlation but also, interestingly, immune relevance of 3 immune cells (macrophages, mast cells and regulatory T cells) and 1 immune-related function (antigen processing cell co-stimulation).

CONCLUSION

We established a novel 12 ferroptosis-related-gene signature that was proven to be an independent prognostic predictor for OS and inferred to be related to tumour immunity in ccRCC; however, the underlying mechanism is still poorly characterized and needs further exploration.

Comprehensive Analysis of a ceRNA Network Reveals Potential Prognostic lncRNAs Involved in Progression of Bladder Cancer.. [DOI: 10.21203/rs.3.rs-434872/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Background: The aberrant expression of long non-coding RNAs (lncRNAs) has attracted more and more attention in the biological field of bladder cancer(BC). We aim to construct a competing endogenous RNA(ceRNA) network reveals potential prognostic lncRNAs involved in progression of BC.Results: Expression profiles of messenger RNA(mRNA), micro RNA(miRNA) and lncRNA of 397 BC samples and 19 non-tumor tissues were downloaded from The Cancer Genome Atlas(TCGA) database. Patients with BC were randomly divided into training group (n=198) and validation group (n=199). Then, 130 lncRNAs, 159 miRNAs and 2,048 mRNAs were identified as differentially expressed genes (DEGs, |logFC|>1, FDR<0.01) related to BC progression. Nextly, we constructed an BC associated deregulated competing endogenous RNA(ceRNA) network with 70 lncRNAs, 30 miRNAs, and 62 mRNAs involved in. Subsequently, a seven-lncRNA signature was constructed by establishing a LASSO Cox model with 13 lncRNAs associated with survival from the ceRNA network. This signature can well distinguish high-risk patients from low-risk patients in training group and verification group. Furthermore, we combined the risk score model with other clinical fictures to estimate the ability of survival prediction. The result suggested that the risk score can be selected as an independent prognostic factor for overall survival(OS) rate. Conclusion: In this study, we construct a ceRNA network related to progression of BC and established an seven-lncRNA signature, which was a candidate prognostic biomarker for prognostic prediction of BC patients .

A novel ferroptosis-related 12-gene signature predicts clinical prognosis and reveals immune relevancy in clear cell renal cell carcinoma.. [DOI: 10.21203/rs.3.rs-153932/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Background Clear cell renal cell carcinoma (ccRCC) is still highly aggressive and lethal even with various therapeutic approaches. As kidney is an iron-metabolism-related organ, exploring and assessing the clinical value of ferroptosis, an iron-dependent regulated cell death, is practical and significant. Methods Prognostic ferroptosis-related differentially expressed genes (DEGs) were identified from KIRC cohort in TCGA database, from which a prognostic signature was established using the Lasso-penalized Cox regression analysis. Each patient in the KIRC cohort and the E-MTAB-1980 cohort (from the ArrayExpress database) was assigned with a calculated signature-correlated risk score and categorized to be either in high- or low-risk group divided by the median risk score in the KIRC cohort. Then, the independent prognostic value of the signature was further assessed by Kaplan-Meier (K-M) survival, time-dependent receiver operating characteristic (ROC) and Cox regression analyses base on overall survival (OS) in both cohorts. Lastly, risk-related DEGs were identified in both cohorts and applied with the enrichment analyses for Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG) and immune infiltration. Results Within 60 ferroptosis-related genes, 32 prognostic DEGs were identified, from which we constructed a prognostic 12-gene signature including CARS1, HMGCR, CHAC1, GOT1, CD44, STEAP3, AKR1C1, CBS, DPP4, FANCD2, SLC1A5 and NCOA4. Patients in both cohorts were divided into high- and low-risk group which were visually distributed in two sets and with positive-risk-related mortality. The K-M survival and the ROC curves validated the signature as prognostic valuable with P <0.05 and area under the curve >0.7 in both cohorts, respectively. Multivariate Cox regression further confirmed the risk score as an independent prognostic predictor for OS. Commonly enriched term in GO and KEGG not only shown a highly iron correlation, but also, interesting, an immunity relevancy of 3 immune cells (macrophages, mast cells and regulatory T cell) and 1 immune-related function (antigen processing cell co-stimulation). Conclusion We established a novel 12 ferroptosis-related-gene signature which was proved as an independent prognostic predictor for OS and inferred as relating to tumor immunity in ccRCC, however, the underlying mechanism is still poorly characterized and needed further exploration.

Long-Term Oncologic Outcomes After Laparoscopic and Robotic Tumor Enucleation for Renal Cell Carcinoma

OBJECTIVES

Tumor enucleation (TE) optimizes parenchymal preservation with promising short-term oncologic outcomes compared with standard partial nephrectomy (SPN). However, researches/literatures about long-term oncologic outcomes for TE after minimally invasive surgery are scarce. We aim to analyze long-term oncologic outcomes after laparoscopic and robotic tumor enucleation for renal cell carcinoma (RCC).

PATIENTS AND METHODS

We retrospectively analyzed 146 patients who underwent TE with either laparoscopic or robotic approach for localized RCC in our center. Local recurrence, cancer specific survival (CSS), recurrence free survival (RFS), and overall survival (OS) were the main outcomes. Survival curves were generated using a Kaplan-Meier method. Perioperative outcomes and pathological outcomes were also analyzed.

RESULTS

Overall, 98 male and 48 female patients were eligible for the study. The median tumor size was 3.4 cm with a median R.E.N.A.L. score of seven. Warm ischemia was used in 143 patients with a median ischemia time of 20 min and three patients had zero ischemia. Five patients (3.4%) had major complications (> Clavien IIIa) and only two were related to urinary system. The median global glomerular filtration rate (GFR) preserved after surgery was 93%. Pseudocapsule invasion was reported in 50 tumors (34%) and positive surgical margins were found in 3/146 (2.1%) tumors. At a median follow-up of 66 months, local recurrence happened in two patients (1.4%), and systemic recurrence happened in six patients (4.2%). The 5-year CSS, RFS, OS were 95.7, 89.6, and 91.9%, and the 10-year CSS, RFS, OS were 93.8, 89.6, and 90.0%, respectively.

CONCLUSION

This study indicates that tumor enucleation with laparoscopic or robotic approach in experienced hands for the treatment of RCC appears oncologically safe with a median follow-up of more than 5 years. Prospective studies with more patients and longer follow-up will be required to further evaluate oncologic safety after TE.

Outcome of postmastectomy radiotherapy after primary systemic treatment in patients with clinical T1-2N1 breast cancer

PURPOSE

The role of postmastectomy radiotherapy following primary systemic treatment in patients with clinical T1-2N1 breast cancer remains a controversial issue. The purpose of this study was to evaluate the benefit of postmastectomy radiotherapy following primary systemic treatment.

PATIENTS AND METHODS

Between 2005 and 2012, in two independent institutions, female patients with T1-2N1 breast cancer receiving primary systemic treatment followed by mastectomy and lymph node dissection because bad response, then treated with or without chest wall and regional lymph node irradiation have been studied retrospectively. The patients received normofractionated radiotherapy using 3D conformal photons or electron techniques. Locoregional recurrence-free survival, distant metastasis-free survival and disease-free survival were calculated using Kaplan-Meier method. Univariate analysis of potential prognostic factors was performed using log-rank test.

RESULTS

Eighty-eight patients have been studied. Of them, 75 patients received postmastectomy radiotherapy. At surgery, 53 patients achieved ypN0. Median follow-up was 67 months. Postmastectomy radiotherapy significantly improved locoregional recurrence-free survival, with a 5-year rate of 96.9% versus 78.6% in the group that did not have postmastectomy radiotherapy. In the subgroup of 53 patients achieving ypN0, postmastectomy radiotherapy improved locoregional recurrence-free survival (a 5-year rate of 94.7% vs. 72.9%), distant metastasis-free survival (a 5-year rate of 92.8% vs. 75%) and disease-free survival (a 5-year rate of 92.9% vs. 62.5%). By univariate analysis, postmastectomy radiotherapy was the only significant prognostic factor affecting locoregional recurrence-free survival.

CONCLUSIONS

For patients with clinical T1-2N1 disease, postmastectomy radiotherapy could significantly improve locoregional recurrence-free survival after primary systemic treatment and be even more therapeutic in the subgroup of patients with good response for primary systemic treatment by improving locoregional recurrence-free, distant metastasis-free and disease-free survival. Larger prospective studies are needed to confirm our findings.

Job Design and Levels of Physical and Mental Strain among Prison Officers

In this paper the preliminary results of a four year longitudinal study concerned with job design and levels of strain among a population of Prison Officers are reported. The job design factors that were studied related to perceived demands, constraints and supports. It was hypothesised that (i) those officers who perceive themselves as having jobs high in demand and level of constraint would suffer more strain than those of equal demand but who had a greater decision latitude (i.e., fewer constraints). It was further hypothesized that (ii) those in highly demanding and constrained jobs would show fewer strain symptoms if the environment in which they worked was perceived as providing social support. Preliminary analysis of the data shows that the first hypothesis was not supported for a measure of general physical well-being. However, there was evidence that those working in high security prisons showed significantly lower levels of general physical health than those working in low security environments. For measures of psychological well-being both hypotheses (i) and (ii) were partially supported. Those who perceived themselves as having high levels of support were found to suffer less from anxiety and depression. These effects were most apparent in the higher security prisons. Additional analyses have shown that the demands supports and constraints model is probably too simplistic and that other variables (e.g. personality) and further refinements to the model would help to account for additional variance in the measures of strain.

Antiproliferation activity of Devil's club (Oplopanax horridus) and anticancer agents on human pancreatic cancer multicellular spheroids

Devil's club (DC, Oplopanax horridus) is an important medicinal herb of the Pacific Northwest which has significant antiproliferation activity against a variety of human tumor cell lines in vitro. This study compared the antiproliferation activity of DC extract alone, and in combination with chemotherapeutic agents gemcitabine (GEM), cisplatin (CDDP), and paclitaxel (PTX) on human pancreatic cancer PANC-1 3D spheroids and 2D monolayer cells. 3D tumor spheroids were prepared with a rotary cell culture system. PANC-1 3D spheroids were significantly more resistant to killing by DC extract, GEM and PTX compared to 2D cells, with IC50 levels closer to that observed in vivo. DC extract significantly enhanced the antiproliferation activity of CDDP and GEM at some concentrations. The bioactive compound identified as a polyacetylene showed strong antiproliferation activity against PANC-1 2D cells and 3D spheroids with IC50 at 0.73±0.04 and 3.15±0.16μM, respectively. 3D spheroids and 2D cells differentially expressed a number of apoptosis related genes. Cell cycle analysis showed that the proportion of cells in S phase was increased and in G2/M phase reduced in 3D spheroids compared to 2D cells. DC extract can potentially be used to enhance the activity of chemotherapeutic agents against pancreatic cancer cells. Use of 3D spheroid model for screening of natural products can potentially increase the efficiency in discovering in vivo bioactive compounds.

Increased calcium deposits and decreased Ca2+-ATPase in right ventricular myocardium of ascitic broiler chickens

Right ventricular hypertrophy and failure is an important step in the development of ascites syndrome (AS) in broiler chickens. Cytoplasmic calcium concentration is a major regulator of cardiac contractile function and various physiological processes in cardiac muscle cells. The purpose of this study was to measure the right ventricular pressure and investigate the precise ultrastructural location of Ca(2+) and Ca(2+)-ATPase in the right ventricular myocardium of chickens with AS induced by low ambient temperature. The results showed that the right ventricular diastolic pressure of ascitic broilers was significantly higher than that of control broilers (P < 0.01), and the maximum change ratio of right intraventricular pressure (RV +/- dp/dt(max)) of ascitic broilers was significantly lower than that of the controls (P < 0.01). Extensively increased calcium deposits were observed in the right ventricular myocardium of ascitic broilers, whereas in the age-matched control broilers, calcium deposits were much less. The Ca(2+)-ATPase reactive products were obviously found on the sarcoplasmic reticulum and mitochondrial membrane of the control right ventricular myocardium, but rarely observed in the ascitic broilers. The data suggest that in ascitic broilers there is the right ventricular diastolic dysfunction, in which the overload of intracellular calcium and the decreased Ca(2+)-ATPase activity might be the important factors.

HCHs and DDTs in sediment-dwelling animals from the Yangtze Estuary, China

HCHs and DDTs in sediment-dwelling animals including mollusks and crabs from the Yangtze Estuary were determined by GC-ECD. Levels of t-HCH were in the range of 1.2-5.5 ng g(-1) and averaged 3.5 ng g(-1) in mollusks, while t-DDT concentrations ranged from 26.0 to 68.8 ng g(-1), with a mean of 34.5 ng g(-1). In crabs t-HCH concentrations varied from 2.0 to 25.7 ng g(-1) and averaged 13.8 ng g(-1), whereas the concentrations of t-DDT were in the range of 1.5-24.8 ng g(-1) with a mean value of 5.9 ng g(-1). The HCHs and DDTs levels depend on geographical position and sources, showing the high levels at fresh water area in the estuary, such as XP, CM and LHK sites, and lower at brackish water area, such as FX site, and little difference between species. Results also indicate there was no significant relationship between t-HCH (t-DDT) concentrations and lipid contents both in mollusks and crabs because of non-equilibrium state under a specific estuarine dynamics; smaller individuals accumulated more HCHs and DDTs than larger individuals of mollusks at LHK site, showing different uptake rate for these pesticides; moreover, HCHs and DDTs levels were lower in female crab bodies than male crab bodies suggesting that the release of spawning. BSAFs (Biota- Sediment Accumulation Factors) from sediment-dwelling animals for HCHs and DDTs show a significant "one high with two low" and "one low with two high" effect in the Yangtze Estuary.

HCHs and DDTs in salt marsh plants (Scirpus) from the Yangtze estuary and nearby coastal areas, China

HCHs and DDTs in salt marsh plants taken from intertidal flats in the Yangtze estuary and coastal area in April and July 2002 were determined by GC-ECD. A significant seasonal effect was observed for HCHs and DDTs in sources and concentration levels in different sample types including above-ground tissues and roots as well as the whole plants and rhizospheric sediments. The results indicated that the concentration of t-HCH was higher in the above-ground tissues than in their roots in April; however, the partitioning of DDTs between contaminated sediments and the roots showed the higher concentrations of t-DDT in their roots. HCHs and DDTs concentration levels were higher in above-ground tissues than in roots in July. BCFs of HCHs and DDTs exhibited lower values with higher levels of contaminants in sediments, and higher values with lower levels in sediments.

Regulation of TNF-Related Apoptosis-Inducing Ligand-Mediated Death-Signal Pathway in Human β Cells by Fas-Associated Death Domain and Nuclear Factor κB

Transfectants of human CM and NES2Y beta cell lines and primary islets transfected by FADD-DN (dominant-negative form of Fas-associated death domain), a mutant of FADD and/or a superrepressor of nuclear factor kappaB (NF-kappaB) (AdIkappaB(SA)2), were examined for their susceptibility to the TRAIL (TNF-related apoptosis-inducing ligand)-induced death signal pathway, compared with controls, wild-type cells, and vector transfectants in caspase fluorescence, Western blot, electrophoretic mobility shift, apoptosis, and cytotoxicity assays. FADD-DN inhibited caspase-8 activation induced by TRAIL in the transfectants of CM and NES2Y cells. TRAIL-induced apoptosis and cytotoxicity to the FADD-DN transfectants were decreased in comparison to those responses in controls (CM, p < 0.01 and p < 0.01; NES2Y, p < 0.05, and p < 0.02, respectively). When CM, NES2Y, and primary islet cells were transfected by AdIkappaB(SA)2, TRAIL-induced IkappaB degradation and nuclear translocation of NF-kappaB p50/p65 were blocked. TRAIL-induced apoptosis and cytotoxicity to AdIkappaB(SA)2 transfectants of these cells were also reduced (CM, p < 0.02 and p < 0.02; NES2Y, p < 0.01 and p < 0.01, respectively, and islet p < 0.01 for cytotoxicity). Finally, cytotoxicity induced by TRAIL in CM and NES2Y cells transfected with both FADD-DN and AdIkappaB(SA)2 was reduced, compared with that observed in these cells transfected with either FADD-DN alone or AdIkappaB(SA)2 alone, suggesting that FADD and NF-kappaB have synergistic proapoptotic regulatory effects on the susceptibility of beta cell lines and islet cells to TRAIL-induced destruction.

TNF-related apoptosis-inducing ligand death pathway-mediated human beta-cell destruction

AIMS/HYPOTHESIS

The aim of this study is to investigate whether apoptosis in human beta cells can be related to the induction of the tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) pathway.

METHODS

We examined the expression of TRAIL and TRAIL receptors in two human pancreatic beta-cell lines and in human primary islet cells using RT-PCR assays and flow cytometric analyses and tested TRAIL-mediated beta-cell destruction in (51)Cr release cytotoxicity assays, Annexin-V and APO-DIREC assays.

RESULTS

Most of the human beta cells express TRAIL receptors-R1, -R2, -R3, -R4 and/or TRAIL. TRAIL induced much stronger cytotoxicity and apoptosis to beta-cell lines CM and HP62 than did FasL, TNF-alpha, LTalpha1beta2, LTalpha2beta1, LIGHT, and IFN-gamma. The cytotoxicity and apoptosis induced by TRAIL to beta-cell lines CM were inhibited competitively by soluble TRAIL receptors, R1, R2, R3 or R4. Treatment of these beta cells with antibodies against TRAIL receptors was able to block the cytotoxicity of TRAIL to these cells. Beta-cell antigen-specific CTL (CD4(+) and CD8(+)) clones express TRAIL, suggesting that these cells are potential sources of TRAIL-inducing beta-cell destruction. Normal primary islet cells from most donors are resistant to the cytotoxicity mediated by TRAIL. However, treatment with an inhibitor of protein synthesis (cycloheximide) or with an enzyme (PI-PLC) that can remove TRAIL-R3 from the islet-cell membrane was able to increase the susceptibility of TRAIL-resistant primary islet cells to the TRAIL death pathway.

CONCLUSION/INTERPRETATION

The TRAIL death pathway is present and can function in human islet beta cells, but unidentified inhibitors of the TRAIL death pathway are present in normal islet cells.

Increased cytosol Ca(2+) and type 1 programmed cell death in Bcl-2-positive U937 but not in Bcl-2-negative PC-3 and Panc-1 cells induced by the 5-lipoxygenase inhibitor MK 886

MK 886, an arachidonic acid-related analog which inhibits the enzyme, 5-lipoxygenase by an indirect mechanism involving the 5-lipoxygenase activating protein, rapidly increased U937 cytosol Ca(2+), much of which localized around the cell nuclei. Five-lipoxygenase activity was not directly involved since the direct redox-dependent 5-LPOx inhibitor, SC-41661A did not increase Ca(2+). U937 cells subsequently undergo classic type 1 programmed cell death. At least initially the ionized calcium originates from internal stores. Coincident with the rise in U937 ionized calcium, MK 886 rapidly increased reactive oxygen species and reduced mitochondrial membrane potential, as judged by several fluorescent probes. The Ca(2+) response of myeloid leukemia-derived HL-60 cells to MK 886 was similar and both cell lines express Bcl-2 protein. Bcl-2-negative Panc-1 and PC-3 cells did not respond to MK 886 with a Ca(2+) signal but did develop oxidative stress and a decline in mitochondrial membrane potential; these events are thought to contribute to the inhibition of cell proliferation and induction of a type 2 PCD. In addition to its marked inhibition of Bcl-2 mRNA synthesis, an interesting hypothesis is that MK 886, serving as a low molecular weight ligand, either by direct or indirect inhibition of U937 Bcl-2 protein function, possibly related to an ion channel activity, alters the distribution of intracellular, possibly nuclear Ca(2+), thereby promoting the development of type 1 programmed cell death.

A response of Panc-1 cells to cis-platinum, assessed with a cDNA array

BACKGROUND

The problem posed by the lack of response of cells in most solid cancers to current chemotherapy generally remains intractable.

MATERIALS AND METHODS

The use of cDNA arrays represents one global approach to identifying reasons for this failure. A messenger RNA response of pancreatic cancer (Panc-1) cells after culture for 24 hours with 12 microM cis-platinum was analyzed with a commercial cDNA array.

RESULTS

Major drug-induced events included inhibition of messenger RNAs associated with cell proliferation and up-regulation of generally countervailing DNA repair, cellular stress, heat shock protein, glutathione stress-related and multiple drug resistance enzyme messenger RNAs, accompanied by a limited programmed cell death response.

CONCLUSION

Induction of widespread normal stress-induced countervailing mRNAs by comparatively non-selective agents such as cis-platinum strongly biases against a successful therapeutic outcome. This paradoxical result of a therapeutic intent provides a further compelling argument for the use of specifically-targeted therapy such as growth factor receptor, tyrosine kinase and other discretely focused agents, probably employed in combinations based on expression of their targets in an individual patient's cancer, as identified by cDNA or proteonomic arrays.

Antibiotic treatment for threatened abortion during the early first trimester in women with previous spontaneous abortion

BACKGROUND

We retrospectively examined the usefulness of antibiotic therapy for management of first-trimester threatened abortion in women with previous spontaneous abortion.

METHODS

From 1993 through 1999, women with first-trimester threatened abortion received antibiotic therapy. Only those with gestational age less than 9 weeks and previous spontaneous abortion were included in this analysis. Women with mild abdominal cramping received amoxicillin plus erythromycin for 1 week; those with severe abdominal pain received amoxicillin plus clindamycin for 1 week. Recurrence was documented on the basis of either lower abdominal pain or vaginal bleeding.

RESULTS

Of the 23 women included, 15 (65%) had abnormal vaginal flora (a score above 4, Nugent's criteria). Seven of 16 women who received amoxicillin plus clindamycin and three of seven who received amoxicillin plus erythromycin had complete resolution of lower abdominal pain and vaginal bleeding without recurrence (p=1). The recurrence rate was higher, though not significantly, in women with abnormal bacterial vaginal flora (8/15 vs. 2/8, p=0.379). Twenty-two (96%) of the 23 pregnancies were carried to term, with no identifiable neonatal anomalies.

CONCLUSIONS

These results suggest the usefulness of early antibiotic therapy in preventing pregnancy loss in women with threatened abortion early in the first trimester, and warrant further clinical trials.

The mode of cell death in H-358 lung cancer cells cultured with inhibitors of 5-lipoxygenase or the free radical spin trap, NTBN

The 5-lipoxygenase inhibitors SC41661A and MK886 with different mechanisms of action and the free radical spin trap, NTBN inhibit proliferation of the human bronchiolar lung cancer cell line NCI H-358 (5807 CRL). With continued culture, the agents induced a form of programmed cell death in which DNA laddering was not detected and ultrastructural changes were not characteristic of classic 'type 1' cellular suicide. The changes were more consistent with a type 2 cytosolic, autophagic form of PCD. MK886 induced strikingly abnormal mitochondrial morphology. Since the lipoxygenase inhibitors and NTBN induce classic type 1 PCD in U937 monoblastoid cells, these agents can activate either pathway, depending upon cell type. It is not certain whether activation of type 1 or 2 pathways depends entirely upon cell lineage and/or initiating agent, if all cells retain both pathways, and if type 1 PCD a more effective mediator of the process. These are all relevant questions for assessing the impact of PCD on malignant cell survival and considering ways in which it might be enhanced.

Cross-reactive rubella virus and glutamic acid decarboxylase (65 and 67) protein determinants recognised by T cells of patients with type I diabetes mellitus

AIMS/HYPOTHESIS

To examine the cross-reaction between viral and beta-cell protein determinants and to further understand the potential role of this mechanism in Type I (insuline-dependent) diabetes mellitus.

METHODS

Immune responses to a panel of 28 viral and beta-cell protein peptides representing selected sequences of rubella virus (RV), Coxsackie virus, human 38 KDa31G and glutamic acid decarboxylase (GAD 65 and 67) proteins in proliferation or cytotoxicity assays have been studied using uncloned and cloned T-cell cohorts from a group of 60 Type I diabetic patients.

RESULTS

Peptide GAD65(252-266) induced the responses of patients with recent onset diabetes in proliferation assays at the highest frequency (77%), whereas GAD67(212-226) stimulated the cellular responses at the highest rate (61%) in patients with late-onset diabetes. RVE1(157-176) was recognised by all groups of patients at the highest frequency and the largest amplitude among the viral peptides tested. T-cell clones specific to GAD65(252-266), GAD65(274-286) or GAD67(212-226) were tested in cytotoxicity assays for their responses to rubella virus peptides. Each of these T-cell clones cross-reacted with two to four rubella virus peptides, including RVE1(157-176) and RVE2(87-107). Analysis of the sequences of cross-reactive viral and glutamic acid decarboxylase antigens showed that these epitopes shared similar peptide binding motifs to HLA DR3/DR4. There is a statistically significant correlation between the response amplitude of patient's peripheral blood mononuclear cells to RVE1(157-176), RVE2(87-107) and GAD65(274-286) in patients with recent onset diabetes, and to RVE1(157-176) and GAD67(212-226) in patients with late onset diabetes.

CONCLUSION/INTERPRETATION

Cross-reactive glutamic acid decarboxylase and rubella virus determinants identified by T-cell clones were also recognised at high frequencies by general T-cell populations of Type I diabetic patients.

Altered oncogene, tumor suppressor and cell-cycle gene expression in PANC-1 cells cultured with the pleiotrophic 5-lipoxygenase inhibitor, MK886, assessed with a gene chip

We describe a genomic response of mRNAs associated with a subset of oncogenes, tumor suppressor and cell cycle-related genes in proliferating human Panc-1 pancreatic cancer cells after 24 hours of culture with MK886, a pleotrophic 5-lipoxygenase inhibitor. Ninety-eight of these cDNAs are represented in one of the sub-arrays included in the Clontech Human cDNA Expression Array. In this initial analysis, control cells exhibited apparent widespread low levels of disparate mRNA synthesis. In cells cultured with 40 microM MK886 for 24 hr, while most expressed genes, including a number of specific proliferation-enhancing genes such as c-myc were inhibited, 19 other ones including some countervailing genes including tyrosine SRC protein kinase, cyclins B1 and D1, CDC25B phosphatase and 40s ribosomal S19, amounting to 19 percent of the cDNAs resident on the chip were up-regulated at > 1.10 experimental/control values. Therapy-induced activation of compensatory proliferative genomic responses provides an additional explanation why malignant cells can fail therapy. Among their many future uses, gene chips clearly will be an extremely powerful tool for identifying relationships between the hierarchical linear and non-linear control and implementation-related cellular events and for identifying potential molecular targets tor cancer therapy.

CD4+ and CD8+ T-cell clones from congenital rubella syndrome patients with IDDM recognize overlapping GAD65 protein epitopes. Implications for HLA class I and II allelic linkage to disease susceptibility

To fully characterize human glutamic acid decarboxylase (GAD)65 protein T-cell epitopes associated with insulin-dependent diabetes mellitus (IDDM), CTL clones specific to GAD65 protein antigens were isolated from two congenital rubella syndrome (CRS)-associated IDDM patients. Overlapping nonamer T-cell epitopes recognized by both CD4+ or CD8+ CTL clones within peptides GAD65(252-266) and GAD65(274-286) were identified as sequences bounded by GAD65(255-266) with 6/9 overlapping residues, and GAD65(276-285) with 8/9 overlapping residues, respectively, using two panels of overlapping peptide analogs in cytotoxicity assays. HLA restrictive elements of the T-cell clones were also identified using a panel of B cell lines with different HLA phenotypes as targets in cytotoxicity assays. The antigenic GAD65 peptides elicited cytotoxic responses of peptide-specific CD4+ T-cell clones in the context of HLA DRB1*0404. The CD8+ T-cell clone specific to GAD65(255-263) was found to be restricted by HLA A3 and A11. Similarly, the CD8+ T-cell clone specific to GAD65(277-285) killed peptide-sensitized target cells expressing HLA B35 and B15. The observed HLA restriction of these overlapping epitopes implies that a tandem of [DRB1*0404-A11(3)] and/or a tandem of [DRB1*0404-B35(15)] might predispose CRS patients to development of IDDM.

Induction of type 1 programmed cell death in U937 cells by the antioxidant, butylated hydroxy-toluene or the free radical spin trap, NTBN

Oxidative stress can initiate programmed cell death and contributes to the patho-physiology of a number of diseases. Low micromolar to millimolar concentrations of various antioxidants or free radical scavengers promote cell growth and reduce cellular suicide induced by several functionally distinct agents, including some known to produce oxidative stress. Severe anoxia or inhibitors of oxidative phosphorylation also initiate programmed cell death. These results seem paradoxical. In order to compare the response of U937 monoblastoid cells to higher concentrations of an antioxidant or a free radical-spin trap, cells were cultured with 20-80 microM concentrations of butylated hydroxy-toluene or with 5 to 60 mM concentrations of the free radical spin trap, N-tertiary butyl phenyl-nitrone. At these concentrations, both agents inhibited cellular proliferation and induced oligosomic DNA, detected by its 'laddering' after electrophoresis on agarose, confirmed by TUNEL (BHT) or flow cytometric (NTBN) evidence of hypodiploid DNA and ultrastructural evidence of a type 1 programmed cell death. The ability of hydroxy-toluenes to oxidize DNA and promote carcinogenesis and whether free radical spin traps could augment or interfere with the response of malignantly transformed cells to chemotherapy or ionizing radiation provide the raison d'etre of these studies.

Free radicals and reactive oxygen species in programmed cell death

Oxidative stress, originating from reactive oxygen species and free radicals provides a constant challenge to eukaryotic cell survival. While implicated in a number of degenerative diseases, some associated with aging and with aging itself, the manner and extent to which oxidative stress contributes to the initiation or implementation of programmed-cell death is problematic. If oxidative stress is an important modulator of programmed-cell death, any ability intentionally to augment or inhibit it might ameliorate diseases in which the process is abnormally underactive or overactive.

Does maximizing programmed cell death necessarily yield an optimum clinical advantage?

Generally it has been believed that a maximum therapeutic induction of programmed cell death in cancer cells is universally desirable. As a corollary, the presence of Bcl-2, a major anti-programmed cell death protein, is considered an unfavorable prognostic sign. The latter is not and the former may not be universally true.

5-Lipoxygenase inhibitors reduce PC-3 cell proliferation and initiate nonnecrotic cell death

BACKGROUND

Products of the arachidonic acid-metabolizing enzyme, 5-lipoxygenase, stimulate the growth of several cell types. Selective inhibitors of the enzyme, including SC41661A and MK886, reduce PC-3 prostate cell proliferation. With continued culture, cells die, but the mode of death, necrotic or nonnecrotic, has not been established.

METHODS

Flow cytometry, laddering after agarose electrophoresis of DNA from inhibitor-treated cells, and light and electron microscopy were employed to examine the type of death in PC-3 prostate cells cultured with either 5-lipoxygenase inhibitor.

RESULTS

The inhibitors induced nonnecrotic, programmed cell death. SC41661A-treated cells exhibited "foamy," vacuolated cytoplasm and mitochondria with disrupted cristae and limiting membranes, while some cells contained numerous polysomes and extended hypertrophic Golgi and secretory cisternal networks. A proportion of the treated cells detached and the nuclei of these cells were characteristic of type 1 "apoptotic" programmed cell death. MK886, a 5-lipoxygenase-inhibitor with a different mechanism of action, induced nonnecrotic changes largely confined to the cytoplasm, most consistent with type 2 "autophagic" programmed cell death. In preliminary studies of mechanism, we demonstrated that PC-3 cells express mRNA for 5-lipoxygenase and for 5-lipoxygenase-activating protein. The less active inhibitor, SC45662 neither reduced proliferation nor induced DNA laddering. The antioxidant, N-acetyl-l-cysteine but not butylated hydroxy toluene or alpha tocopherol, partially reduced the inhibition of proliferation from SC41661A.

CONCLUSIONS

SC41661A and MK886 inhibit PC-3 cell proliferation and induce a form of type 1 or type 2 programmed cell death, respectively. PC-3 cells contain messenger RNA for 5-lipoxygenase and 5-lipoxygenase-activating proteins. Drug-induced changes included altered redox potential, inferred from the increased survival due to the antioxidant and glutathione precursor, N-acetyl-l-cysteine. PC-3 cells are an appropriate model for studying the mechanism responsible for 5-lipoxygenase inhibitor-induced cellular suicide.

Point mutation of a rubella virus E1 protein T-cell epitope by substitution of single amino acid reversed the restrictive HLA-DR polymorphism: a possible mechanism maintaining HLA polymorphism

The influence of single amino acid substitutions within a rubella E1 protein T-cell epitope, E1(273-284) on T-cell recognition was studied. Substitutions of an uncharged amino acid A for an E or for a T and substitution of a T for S were found to not significantly reduce the T-cell responses. However, substitution of a charged residue such as E for hydrophobic residues (I, V, or W); D for Q; or a relatively larger size amino acid for polar residues completely abolished the cytotoxicities mediated by E1(273-284)-specific T-cell clone. A set of single amino acid-substituted peptide analogs of E1(273-284) not eliciting cytotoxicity of the T-cell clone was used to test the influence of point mutation of the epitope on HLA DR restrictions. A panel of B-cell lines with different DR4 subtypes was used as targets in cytotoxicity assays to determine the restrictive HLA molecules. Results showed that modification of the T-cell epitope by point mutation could reverse the HLA DR restriction from one allele to other alleles. A model based on these results has been proposed to explain the mechanism balancing major histocompatibility complex (MHC) polymorphism in outbred populations.

A new categorization of HLA DR alleles on a functional basis

In this analysis, we introduce a new categorization of HLA DR alleles which are important members of HLA class II genes encoding cell surface glycoproteins that function to present antigenic peptides to T cells. We have grouped all HLA DR molecules into seven different functional categories on the basis of their ability to bind and present antigenic peptides to T cells and their association with susceptibility or resistance to disease. This novel categorization of DR alleles on the basis of function allows for the prediction of seven similar subregion structures (supertypes or supermotifs) within pocket 4 of HLA DR peptide binding groove as the molecular basis for grouping these alleles. The physicochemical characteristics of HLA DR supertype residues, charge in particular, may influence the selectivity for binding peptide, dominate promiscuous T-cell recognition of antigenic peptides, and affect HLA DR disease associations. To rationalize the functional categories of DR alleles, we have further combined the seven DR supertype patterns into three groups based on the charges of residues within the supertypes. Grouping HLA DR alleles into functional categories may assist in understanding the mechanistic basis of autoimmunity, resolving current paradoxes in HLA disease associations, and developing new immunotherapy strategies.

NTBN, a free radical spin trap induces programmed cell death in human pancreatic cancer (PANC-1) cells

N-tertiary butyl-a-phenylnitrone, a free radical spin trap at > or = 10 mM concentration, inhibited proliferation and reduced the viability of human pancreatic cancer (Panc-1) cells. The drug concentration determined the extent of inhibition, and with continued culture a proportion of the cells detached, most of which stained with trypan blue. Although hypodiploid cells were detected by flow cytometry of cells cultured with 20 mM NTBN, DNA laddering was absent and the TUNEL reaction negative. "Dark" cells present in samples cultured with 10 mM NTBN exhibited decreased cytoplasmic volume and increased staining with methylene blue and azure II, but lacked characteristic nuclear changes of type 1 programmed cell death. Cells cultured with > 10 mM of the spin trap exhibited nuclear and cytoplasmic changes more consistent with a non-type 1, type 2 variant of PCD with extensive cytoplasmic vacuolization. Careful analysis revealed evidence of marked pinocytosis in some cells. In view of the spin-trap associated pinocytosis, augmented uptake of chemotherapy in affected cells might be anticipated, but additive, synergistic or antagonistic interactions between NTBN and 5-fluorouracil were not observed.