Basic mechanisms of Friend virus-induced immunomodulation and tumorigenesis (154.34)

Friend murine leukemia Virus (FV) infection of immunocompetent mice is a well established model to acquire further knowledge about retrovirus-associated mechanisms, enabling the development of preventive and therapeutic treatments against retrovirus-induced diseases. Our own studies show that formation of the immunological synapse between FV-infected DCs and T cells is altered. Those DCs induced a regulatory phenotype and suppressive function in cocultured CD4+ T cells (Treg). In order to identify key molecules that contribute to this Treg induction, expression patterns of cytoplasmatic proteins in uninfected and FV-infected DCs were comparatively analyzed by Protein-mass fingerprinting. By that approach about 600 differentially expressed proteins were identified. Interestingly, many of these are cytoskeletal proteins, and some are known to be involved in DC-T cell interactions (e.g. Myosins1F, 9, and 14). Notably, several MHCII antigens are downregulated in FV-infected DCs as compared with uninfected DCs. Recent studies show that the endocytic capacity of FV-infected DCs was significantly enhanced as compared with control DCs. Our current work is focussed on elucidating the function of signalling proteins which are differentially expressed in FV-infected vs. uninfected DCs. Taken together, our work is aimed to understand how retroviral infection of DCs alters DC-T cell interactions, and at which extent these effects contribute to retrovirus-induced immunosuppression.

Discovery of entry inhibitors for HIV-1 via a new de novo protein design framework

A new (to our knowledge) de novo design framework with a ranking metric based on approximate binding affinity calculations is introduced and applied to the discovery of what we believe are novel HIV-1 entry inhibitors. The framework consists of two stages: a sequence selection stage and a validation stage. The sequence selection stage produces a rank-ordered list of amino-acid sequences by solving an integer programming sequence selection model. The validation stage consists of fold specificity and approximate binding affinity calculations. The designed peptidic inhibitors are 12-amino-acids-long and target the hydrophobic core of gp41. A number of the best-predicted sequences were synthesized and their inhibition of HIV-1 was tested in cell culture. All peptides examined showed inhibitory activity when compared with no drug present, and the novel peptide sequences outperformed the native template sequence used for the design. The best sequence showed micromolar inhibition, which is a 3-15-fold improvement over the native sequence, depending on the donor. In addition, the best sequence equally inhibited wild-type and Enfuvirtide-resistant virus strains.

Effect of G-CSF prophylaxis on the occurrence of neutropenia in men receiving cabazitaxel plus prednisone for the treatment of metastatic castration-resistant prostate cancer (mCRPC) in the TROPIC study

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Background: The phase III TROPIC study showed that cabazitaxel plus prednisone (CbzP) improves survival compared with mitoxantrone plus prednisone (MP) in men with mCRPC who progressed after docetaxel-based therapy (HR 0.70; p<0.001; Lancet 2010;376:1147). In this study, a higher percentage of men in the CbzP group had grade ≥3 neutropenia (81.7% versus 58.0%). We analyzed the effect of G-CSF use on the occurrence of grade ≥3 neutropenia.

Methods: 755 men with mCRPC who progressed during or after a docetaxel-containing regimen were randomized to receive 10 mg of oral prednisone daily and either 12 mg/m2 of mitoxantrone or 25 mg/m2 of cabazitaxel every 3 weeks. Primary prophylaxis with G-CSF was not permitted at cycle 1, but was allowed after the first occurrence of neutropenia either lasting ≥7 days or complicated by fever >38.5°C, or fever >38.1°C for three observations during a 24- hour period, or infection. We analyzed the effect of G-CSF use on the occurrence of neutropenia in cycles 2–10. G-CSF use was defined as either prophylactic (administered within 3 days of chemotherapy dose) or therapeutic (administered more than 3 days after chemotherapy dose).

Results: A total of3246 cycles (1881 CbzP; 1365 MP) were administered from cycle 2 onward. No G-CSF was used in 2,322 cycles (1144 CbzP; 1178 MP) and the percentage of these cycles with grade ≥3 neutropenia was similar between the groups (44.6% CbzP; 38.4% MP). G-CSF was used in more cycles in the CbzP group as prophylaxis (588 CbzP; 118 MP; chi-square P<0.0001) and therapeutically (149 CbzP; 69 MP; P=0.0013). The percentage of CbzP cycles with grade ≥3 neutropenia was lower when G-CSF was used early as prophylaxis versus using it later as a therapeutic modality (24.7% versus 57.7%; P<0.0001). A reduction in grade ≥3 neutropenia favoring prophylactic versus therapeutic G-CSF was also observed in the MP group (9.3% versus 33.3%; P<0.0001).

Conclusions: The appropriate and timely use of G-CSF as prophylaxis reduces the occurrence of neutropenia in men receiving CbzP for mCRPC. Adherence to current guidelines on the use of G-CSF is recommended to manage this predictable side effect.

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Combination of hsa-miR-375 and hsa-miR-142-5p as a predictor for recurrence risk in gastric cancer patients following surgical resection

BACKGROUND

Recurrence is a major factor leading to treatment failure and death in gastric cancer (GC) patients following surgical resection. Importantly, the prediction of recurrence is critical in improving clinical outcomes. We isolated a group of microRNAs (miRNAs) and evaluated their usefulness as prognostic markers for the recurrence of GC.

PATIENTS AND METHODS

A total of 65 GC patients were selected for systematic analysis, 29 patients with recurrence and 36 patients without recurrence. Firstly, miRNAs microarray and bioinformatics methods were used to characterize classifiers from primary tumor samples (n = 8). Following, we validated these predictors both in frozen fresh and paraffin-embedded tissue samples (n = 57) using quantitative PCR.

RESULTS

We have identified 17 differential miRNAs including 10 up-regulated and 7 down-regulated miRNAs in recurrence group. Using k-top scoring pairs (k-TSP) method, we further ascertained hsa-miR-375 and hsa-miR-142-5p as a classifier to recognize recurrence and nonrecurrence cases both in the training and test samples. Moreover, we validated this classifier in 34 frozen fresh tissues and 38 paraffin-embedded tissues with consistent sensitivity and specificity with training set; among them, 15 cases were matched. A high frequency recurrence and poor survival were observed in GC cases with high level of hsa-miR-375 and low level of hsa-miR-142-5p (P < 0.001). In addition, we evaluated that hsa-miR-375 and hsa-miR-142-5p were involved in regulating target genes in several oncogenic signal pathways, such as TP53, MAPK, Wnt and vascular endothelial growth factor.

CONCLUSION

Our results indicate that the combination of hsa-miR-375 and hsa-miR-142-5p as a predictor of disease progression has the potential to predict recurrence risk for GC patients.

Phase II trial of irinotecan and cisplatin combination as first-line chemotherapy in patients with advanced esophageal squamous-cell carcinoma: An interim report

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Background: Although the irinotecan and cisplatin combination has been used in esophageal cancer treatment, we tested the combination specifically in unresectable or metastatic esophageal squamous cell carcinoma with different doses to decrease the toxicity and keep the efficacy.

Methods: Patients were eligible if they had histologic proof of unresectable or metastatic squamous cell carcinoma of the esophagus, between 18-75 years of age with a Karnofsky performance status ≥ 80. No prior chemotherapy was allowed. Patients were treated with irinotecan 130 mg/m2 and cisplatin 60 mg/m2 repeated 3 weeks. Response was evaluated every two cycles of treatment by using RECIST criteria. The sample size was calculated using Simon's 2-stage design. The primary end point of the study was objective response rate. The second end points are PFS and toxicity. Accrual was planned to a total of 46 patients with the targeted response rate of 50%. The first stage requires at least 7 or more out of 16 patients to have a confirmed partial or complete response before proceeding to the second stage.

Results: Twenty one patients have been enrolled so far, of which 16 patients were assessable for response. The overall response rate was 43.8%(7/16), including one complete response (6.3%) and six partial response (37.5%). Among 13 patients who presented with dysphagia at baseline, 10 (62.5%) had the symptom either completely resolved or significantly improved. The most common toxicities were neutropenia, diarrhea and alopecia. Seven patients (33.3%) developed grade 3 neutropenia and one had (4.8%) with febrile neutropenia. One patient (4.8%) had grade 3 diarrhea. There were no treatment-related deaths.

Conclusions: The combination of irinotecan plus cisplatin with lower doses showed equivalent efficacy and less toxicity in patients with unresectable or metastatic squamous-cell carcinoma of the esophagus. The study is ongoing.

No significant financial relationships to disclose.

A phase II, open-label, multicenter, prospective study of paclitaxel plus capecitabine with subsequent capecitabine maintenance therapy as first-line treatment for metastatic or recurrent gastric cancer

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Background: Paclitaxel has been shown to be effective in AGC. We assess the efficacy and safety of PX-X therapy as first-line treatment for metastatic or recurrent GC in a phase II, multicenter, prospective study.

Methods: Patients with previously untreated gastric adenocarcinoma, signed informed consent, target lesion(s), KPS ≥ 70 and adequate organ functions are eligible. Paclitaxel was given as 80 mg/m2 by 3-hour infusion day 1,8, capecitabine 1,000 mg/m2, BID, D1-14, Q3W. Cycles were repeated until progression or maximum 6 or AEs. Then the patients without progression began the second stage treatment as X with same dose/schedule until progression or AEs. PFS, RR, DCR, OS and AEs are the end points evaluated in this study.

Results: From 12/2006 to 4/2010, 195 patients (ITT) were enrolled in 21 centers, 1 patient was withdraw due to allergy to paclitaxel, 194 cases were PP. After median follow up of 16.2 months, 16 cases lost. In ITT, 119 pts progressed, 104 pts died. Mean cycles the patients completed was 5. CR and PR were achieved in 1.0% (2 pts) and 32.3% (63 pts) of pts (RR 33.3%), 75 pts had SD (38.5%), 25 pts (12.8%) progressed. PFS of ITT is 208 d (95% CI: 169.1-246.8) and estimated OS is 456 d (95%CI: 286.9-624.2). 45 pts continued to X after PX with good tolerance, median cycles accepted was 4, and OS was longer than 590 d. 23 patients accepted surgery after chemotherapy; the survival data have not been reached. After disease progression, 61 cases accepted second-line treatment, including oxaplatin/irinotecan-based chemotherapy, target therapy, and local therapy. AEs were mild and the grade 3/4 toxicities were leucopenia (13.8%), alopecia(13.3%), neutropenia (8.2%), fatigue (6.7%), nausea/vomiting (5.1%), HFS (5.1%), diarrhea(3.6%), neurotoxicity (3.1%), hepatic dysfuction (2.6%), and anaphylactic shock (0.5%). No treatment- related deaths were recorded in all patients.

Conclusions: PX-X as first-line treatment was promising in advanced gastric cancer. Further evaluation of this combination therapy is being carried on phase III clinical trial of ML22697.

No significant financial relationships to disclose.

Post-operative imatinib in patients with intermediate or high risk gastrointestinal stromal tumor

AIMS

This study aims to determine whether adjuvant treatment with imatinib improves recurrence-free survival (RFS) in Chinese patients undergoing complete resection of localized primary gastrointestinal stromal tumor (GIST) compared with those not receiving adjuvant therapy. We also sought a correlation between c-KIT mutations and RFS.

METHODS

Patients who had undergone complete tumor resection with intermediate or high risk of recurrence were enrolled in a single-center, non-randomized, prospective study. Patients either received adjuvant imatinib therapy (400 mg once-daily) for 3 years or did not. Mutation analyses of c-KIT were performed on available archival tumor samples.

RESULTS

105 patients were enrolled: 56 in the treatment group and 49 in the control group. Median follow-up was 45(43.1-46.9) months. RFS at 1, 2 and 3 years were higher in the treatment group than in the control group (100% vs. 90% at 1 year; 96% vs. 57% at 2 years; 89% versus 48% at 3 years, P < 0.001, HR = 0.188). Subgroup analyses showed that adjuvant therapy significantly decreased the risk of recurrence in patients whether at high risk or at intermediate risk compared with control patients (3-year RFS: 95% vs. 72%, in intermediate risk; 85% versus 31% in high risk; P < 0.001). In addition, imatinib adjuvant treatment decreased the risk of death (P = 0.025, [corrected] HR = 0.254).

CONCLUSIONS

Adjuvant imatinib can improve 1-, 2- and 3-year RFS rates in patients at intermediate or high risk of recurrence after complete tumor resection.

CLINICAL TRIALS REGISTRATION NUMBER

ChiCTR-TCC-00000582.

Genome-wide association study of CSF biomarkers Abeta1-42, t-tau, and p-tau181p in the ADNI cohort

OBJECTIVES

CSF levels of Aβ1-42, t-tau, and p-tau181p are potential early diagnostic markers for probable Alzheimer disease (AD). The influence of genetic variation on these markers has been investigated for candidate genes but not on a genome-wide basis. We report a genome-wide association study (GWAS) of CSF biomarkers (Aβ1-42, t-tau, p-tau181p, p-tau181p/Aβ1-42, and t-tau/Aβ1-42).

METHODS

A total of 374 non-Hispanic Caucasian participants in the Alzheimer's Disease Neuroimaging Initiative cohort with quality-controlled CSF and genotype data were included in this analysis. The main effect of single nucleotide polymorphisms (SNPs) under an additive genetic model was assessed on each of 5 CSF biomarkers. The p values of all SNPs for each CSF biomarker were adjusted for multiple comparisons by the Bonferroni method. We focused on SNPs with corrected p<0.01 (uncorrected p<3.10×10(-8)) and secondarily examined SNPs with uncorrected p values less than 10(-5) to identify potential candidates.

RESULTS

Four SNPs in the regions of the APOE, LOC100129500, TOMM40, and EPC2 genes reached genome-wide significance for associations with one or more CSF biomarkers. SNPs in CCDC134, ABCG2, SREBF2, and NFATC4, although not reaching genome-wide significance, were identified as potential candidates.

CONCLUSIONS

In addition to known candidate genes, APOE, TOMM40, and one hypothetical gene LOC100129500 partially overlapping APOE; one novel gene, EPC2, and several other interesting genes were associated with CSF biomarkers that are related to AD. These findings, especially the new EPC2 results, require replication in independent cohorts.

The alteration of extracellular signal-regulated kinase (ERK) activity of COS7 cells from interphase to mitosis

Although many reports have suggested that ERK1/2 activity is increased in interphase and inhibited in mitosis, the change of ERK1/2 activity from interphase to mitosis is largely undefined. In this study, we examined the alteration of ERK1/2 activity in COS7 cells in response to nocodazole. Nocodazole&mdash;treated or nocodazole&mdash;untreated COS7 cells were stimulated by EGF. We found that ERK1/2 activity of nocodazole&mdash;treated cells was decreased with prolonged time of cells treated with nocodazole while being increased in nocodazole&mdash;untreated cells. COS7 cells became round after being treated with nocodazole for 4 hr. And from the time point, ERK1/2 activity was gradually and significantly inhibited. Furthermore, we showed that MEK activity was greatly decreased compared with nocodazole&mdash;untreated cells after the cells were treated by nocodazole for 8 hr and then EGF. In addition, the migration of cells was inhibited in response to nocodazole. Taken together, we concluded that ERK1/2 activity was gradually inhibited from interphase to mitosis and the cell migration was affected by nocodazole.

Public understanding of risks from gene-environment interaction in common diseases: implications for public communications

BACKGROUND/AIMS

Public understanding of the relationship between health behaviors and genes is likely to affect the motivational impact of learning information about one's own genes. Extant research has featured difficulty measuring public understandings of this relationship. This essay explores public understanding of the relationship between genes and behavior, especially with regard to the mathematical relationships to risk concept. It contributes a psychometrically valid scale for measuring beliefs about gene- behavior relationships.

METHODS

Three population representative surveys (n = 633, 658, 1,218) were conducted using the Knowledge Networks panel platform.

RESULTS

Interpretations of risk vary depending on whether genes and behavior are conceived of as health-damaging (loss frame) or health-protecting (gain frame). In the loss frame, the majority of the population adopts an additive model of the relationship with approximately one-third adopting an amplificative model. In the gain frame, beliefs are divided roughly equally among additive, amplificative and sub-additive models. Scores on the nonmathematically based scale indicate higher belief in the existence of interaction than scores on the more concrete question format.

CONCLUSIONS

The existence of different interpretations of gene-behavior relationships based on gain/loss frame and abstract/concrete modes indicates the need to select frame and mode carefully in both teaching and research. Research is needed to identify optimal configurations for teaching and presenting this relatively complex material.