Basic anatomy and tumor biology of the RPS6KA6 gene that encodes the p90 ribosomal S6 kinase-4

The RPS6KA6 gene encodes the p90 ribosomal S6 kinase-4 (RSK4) that is still largely uncharacterized. In this study we identified a new RSK4 transcription initiation site and several alternative splice sites with a 5’RACE approach. The resulting mRNA variants encompass four possible first start codons. The first 15 nucleotides (nt) of exon 22 in mouse and the penultimate exon in both human (exon 21) and mouse (exon 24) RSK4 underwent alternative splicing, although the penultimate exon deleted variant appeared mainly in cell clines, but not in most normal tissues. Demethylation agent 5-azacytidine inhibited the deletion of the penultimate exon whereas two indolocarbazole-derived inhibitors of cyclin dependent kinase 4 or 6 induced deletion of the first 39 nt from exon 21 of human RSK4. In all human cancer cell lines studied, the 90-kD wild type RSK4 was sparse but, surprisingly, several isoforms at or smaller than 72-kD were expressed as detected by seven different antibodies. On immunoblots, each of these smaller isoforms often appeared as a duplet or triplet and the levels of these isoforms varied greatly among different cell lines and culture conditions. Cyclin D1 inhibited RSK4 expression and serum starvation enhanced the inhibition, whereas c-Myc and RSK4 inhibited cyclin D1. The effects of RSK4 on cell growth, cell death and chemoresponse depended on the mRNA variant or the protein isoform expressed, on the specificity of the cell lines, as well as on the anchorage-dependent or -independent growth conditions and the in vivo situation. Moreover, we also observed that even a given cDNA might be expressed to multiple proteins; therefore, when using a cDNA, one needs to exclude this possibility before attribution of the biological results from the cDNA to the anticipated protein. Collectively, our results suggest that whether RSK4 is oncogenic or tumor suppressive depends on many factors.

Socioeconomic status and children with intellectual disability in China

BACKGROUND

Intellectual disability (ID) accounts for 70% of all disabilities among children in China's Second National Sampling Survey on Disability. Although studies have shown a relationship between social class and ID in children, none have investigated the association of socioeconomic variables in Chinese children with mild or severe ID.

METHODS

Data for children aged 0-6 years with and without ID were abstracted from the Second National Sampling Survey on Disability in China, conducted in 2006. Crude odds ratios showed the effect of sociodemographic factors on mild and severe ID. Adjusted odds ratios (OR(a) ) (95% confidence intervals) estimated the independent effects of these factors.

RESULTS

For both mild and severe ID, risk of having ID increased with male sex, birth to a woman aged 35 years and older, lower maternal education, mother's older age at delivery, lower income and rural residence. After age, gender and parent disability were controlled, mothers aged 35 years and older were more likely to have a child with ID: mild ID, OR(a) 1.47 (1.15-1.88); severe ID, OR(a) 1.32 (1.00-1.73). There was an approximate increasing monotonic risk of severe ID with increasing socioeconomic disadvantage: lowest income, OR(a) 3.00 (2.19-4.12); low income, OR(a) 2.28 (1.63-3.19); lower middle income, OR(a) 1.72 (1.27-2.33); middle income, OR(a) 1.73 (1.28-2.36).

CONCLUSIONS

There is a significant relationship between sociodemographic factors and ID. Similar patterns were found for both mild and severe ID. Recommendations are given for preventing ID in Chinese children.

Cucumber mosaic virus suppressor 2b binds to AGO4-related small RNAs and impairs AGO4 activities

Cucumber mosaic virus suppressor 2b (CMV2b) is a nuclear viral suppressor that interferes with local and systemic silencing and inhibits AGO1 slicer activity. CMV2b-mediated transgene hypomethylation and its localization in Cajal bodies suggests a role of CMV2b in RNA-directed DNA methylation (RdDM). However, its direct involvement in RdDM, or its binding with small RNAs (sRNAs) in vivo is not yet established. Here, we show that CMV2b binds both microRNAs (miRNAs) and small interfering RNAs (siRNAs) in vivo. sRNA sequencing data from the CMV2b immunocomplex revealed its preferential binding with 24-nt repeat-associated siRNAs. We provide evidence that CMV2b also has direct interaction with the AGO4 protein by recognizing its PAZ and PIWI domains. Subsequent analysis of AGO4 functions revealed that CMV2b reduced AGO4 slicer activity and the methylation of several loci, accompanied by the augmented accumulation of 24-nt siRNAs in Arabidopsis inflorescences. Intriguingly, CMV2b also regulated an AGO4-related epiallele independently of its catalytic potential, which further reinforces the repressive effects of CMV2b on AGO4 activity. Collectively, our results demonstrate that CMV2b can counteract AGO4-related functions. We propose that by adopting novel counter-host defense strategies against AGO1 and AGO4 proteins, CMV creates a favorable cellular niche for its proliferation.

PD04-04: Sexual Dysfunction in Women with Early Stage Breast Cancer on Endocrine Therapy: Encouraging Results from a Prospective Study

Background: While the side effects of endocrine therapy (ET) for early stage breast cancer (EBC) have been extensively studied, the link between ET and sexual dysfunction (SD) remains a contentious issue. Most studies have focused on documenting only the presence of problems in specific domains of endocrine symptoms (ES) (e.g. hot flushes, vaginal dryness) and sexual functioning (SF) (interest, satisfaction, arousal, lubrication) without also taking sexual distress into account. To our knowledge, there have been no prospective longitudinal studies evaluating SF and SD before the onset of ET and after treatment initiation. We report the initial 6 month results of this study of SD in women initiating ET for EBC.

Methods: Hormone receptor positive EBC post-menopausal women were approached for a larger study of SF aimed at comparing the prevalence of SD across endocrine agents (tamoxifen vs aromatase inhibitor) and at evaluating the impact of anxious predisposition and ES on SD. Here we report on changes in ES, SF and SD after 6 months of ET. SF was evaluated with the Female Sexual Function Index (FSFI) while sexual distress was assessed with the Female Sexual Distress Scale. ES were measured with FACT-B ES subscale. Participants completed questionnaires prior to initiation (T0) of ET and at 6 months (T1). SD was assessed using the APA classification.

Results: Between January 2009 and May 2011, 118 EBC patients entered the study and 83 have completed both assessments (mean age 62; 30% received chemotherapy). Over time, the levels of ES increased (p <0.001). Despite the worsening of ES at T1, no decline in SF was observed, this for each FSFI domain (desire, arousal, lubrication, discomfort during intercourse and satisfaction). There was no change in the percentage of women reporting 1 or more sexual problems over time (85% vs 87%, ns) nor in the percentage who were sexually distressed (32% vs 34%, ns). The prevalence of SD did not increase after 6 months of ET (T0=28% vs T1=33%, ns). There were no differences in the percentage of women who worsened (i.e., no SD at T0 but SD at T1, 12%) and those who improved (SD at T0 but no SD at T1, 7%) over time (McNemar X2, p >.5) Importantly, women classified as experiencing SD at T0 were more likely to also experience SD at T1 (OR=4.5, 95% CI=2.162 to 9.366) than women who had no SD at T0.

Discussion: This is the first prospective case cohort study evaluating ES, SF and SD in women with EBC on ET. The good news for women is that although ES increased during ET (p < 0.001), this did not have a negative impact on sexual problems (85% vs 87%, ns) or SD (32% vs 34%, ns). This is encouraging news but longer follow-up of these women will provide further insight into the impact of ET on ES and SD over time (> 6 months). The impact of specific types of ET on ES, and SD will also be evaluated. Of interest, the high uptake and high completion rate (>80%) of questionnaires, indicate this is a matter of relevance and importance to women taking adjuvant ET and merits acknowledgement and sensitive discussion.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr PD04-04.

P4-15-01: High Prevalence of Prospective Memory (PM) Impairment in Early Breast Cancer (EBC) Survivors within 1 Year of Adjuvant Chemotherapy Completion: Novel Findings Concerning Post Chemotherapy Cognitive Effects

Background Numerous studies have demonstrated that EBC survivors report more memory problems than healthy controls. However, evidence of impairment on objective tests of memory remains inconclusive. Past research has focussed exclusively on retrospective memory (remembering information from the past when asked to do so), but the complaints of EBC patients appear better described as “prospective memory” failures defined as forgetting to carry out in the future previously formed intentions. The effective performance of many day-to-day activities relies on PM and its impairment has negative consequences in everyday life. Despite its high ecological relevance, no study has evaluated PM functioning in EBC survivors. Consequently, we assessed the prevalence of PM impairment among EBC survivors in the year following completion of chemotherapy. Methods We undertook a cross sectional quantitative case-control study aiming to recruit 80 patients from the Ottawa Hospital Regional Cancer Centre and 80 matched healthy controls from the community. Patients were within 1 year of having completed a first course of chemotherapy. A standardized test of prospective memory (Memory for Intention Screening Test) was administered to both groups. Following the International Cognition and Cancer Task Force recommendation (2008), impairment was defined as a score that fell one standard deviation below the mean performance of the control group. Standardized measures of depression (CESD), anxiety (STAI) and fatigue (Fact-F) were also completed. Results Data are available on 36 patients and 18 controls. Age was well balanced between the groups (case-control mean age 54y vs. 51y, respectively, p=.204). Overall PM impairment was observed in 41% of the participants. More importantly, the rate of PM impairment was significantly higher in the EBC group than controls (53% vs 17%; p < 0.005; odds ratio = 5.588; 95% CI=1.376 to 22.7). Multivariate logistic regression showed that PM performance was unaffected by age (p=0.459), depression (p=0.358), anxiety (p=0.512) or fatigue (p=0.595). Conclusions These preliminary findings provide further support for the hypothesis that breast cancer treatment can impair cognitive processes and yield new and important insights into the type of memory problems experienced by EBC survivors. They suggest that a significant proportion of patients exhibit deficits in PM, an aspect of memory involved in effective daily functioning. Our results also suggest that emotional distress and fatigue do not contribute to PM functioning. Further studies in this area should be directed at understanding the severity and duration of PM impairment. Acknowledging and studying this vexing problem in EBC survivors will aid in developing appropriate rehabilitation strategies.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P4-15-01.

OT3-02-01: A 1-Year Prospective Longitudinal Study of the Role of Psychosocial Factors in Adherence to Adjuvant Endocrine Therapy in Early Breast Cancer

Background: Extensive evidence suggests that endocrine therapy (ET) and adherence to adjuvant ET directly impacts on disease-free and overall survival in women with hormone receptor positive (HR+) early stage breast cancer (EBC). Despite this, adherence to ET is suboptimal, with 35%-50% of patients discontinuing therapy earlier than recommended. Interventions to improve adherence are lacking, due in part to a poor understanding of the modifiable risk factors influencing adherence. Virtually all authors have focused on educational needs of patients and side effect management of ET but there remains a paucity of data on how potentially modifiable psychosocial factors present at outset of treatment initiation influence adherence. We believe that a better understanding of these factors may lead to interventions which enable women to adhere to long term life-saving therapies. This study aims to identify such factors guided by the Common-Sense Model of Self-Regulation which proposes that cognitive, emotional, coping and interpersonal factors are modifiable determinants of adherence.

Study Design: The study is a single centre prospective longitudinal quantitative study. Women diagnosed with HR+ EBC for which endocrine therapy is intended will be enrolled. Participants will complete questionnaires prior to initiating ET, then at 3, 6 and 12 months. The predictor variables are: 1) modifiable factors including illness and treatment cognitions, self-efficacy in coping with side effects anticipated or experienced, fear of breast cancer recurrence, trait anxiety, patient-physician interaction, 2) treatment-induced toxicities and 3) clinical factors including ET, chemotherapy, radiation, cancer stage and menopausal status. The outcome variable is adherence measured at each assessment post-treatment initiation with pill counts and participants'self-report.

Inclusion criteria: 1.Histologically proven Stage I, II, IIIa EBC; 2. Treatment with ET (tamoxifen or an aromatase inhibitor).

Specific Aims: To evaluate the impact on adherence to ET by 1) potentially modifiable psychosocial factors 2) side effects and 3) clinical factors.

Statistical Method: Adherence responses will be transformed into dummy coded variables (0=take ET as prescribed; 1=does not take ET as prescribed). For each assessment, several separate univariate logistic regressions will be conducted with demographic (age, education, work and marital status, ethnicity), cognitive (illness and treatment perception), emotional (fear of recurrence and anxiety), coping (self-efficacy), and patient-physician relationship (role preference, trust and satisfaction), severity of side effects and clinical factors, as independent predictors of adherence. Only predictors which are significant at the 0.25 level will be entered in subsequent hierarchical multiple regression models to identify the main determinants of adherence.

Accrual: Expected study accrual is 200 over 12–18 months. Accrual started in May of 2011 and 36 patients have been accrued to the study.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr OT3-02-01.

Assessment of the Virchow-Robin Spaces in Alzheimer disease, mild cognitive impairment, and normal aging, using high-field MR imaging

BACKGROUND AND PURPOSE

VRSs are the perivascular spaces surrounding the deep perforating arteries in the brain. Although VRS variations with age and disease pathologies have been reported previously, the radiologic characteristics of the VRS in relation to AD are poorly understood. This study investigated the prevalence, spatial distribution, and severity of the VRS in AD, MCI, and older adults who were CN. It also investigated the relationship of the VRS to white matter changes.

MATERIALS AND METHODS

Structural MR imaging data were acquired from 158 participants (AD = 37, MCI = 71, CN = 50, mean age = 74.97 ± 7.20 years) who had undergone T1WI at 3T. The severity of VRS in the white matter, basal ganglia, hippocampus, and brain stem structures was evaluated by using a semiquantitative scale, adapted from existing rating scales. A VRS total score summarizing the subscales was calculated to assess the whole-brain VRSs.

RESULTS

VRSs were observed in multiple brain regions of all participants, typically presented as <2-mm well-margined symmetric round-, oval- and linear-shaped hypointensities on T1WI. The VRS total score increased with leukoaraiosis, atrophy, and advanced age (P < .001). Individuals with AD and MCI showed greater levels of VRS than control subjects. The VRS total score discriminated individuals with AD and those who were CN with an accuracy of 0.79 (95% CI, 0.69-0.89).

CONCLUSIONS

VRSs are common in older adults and are more severe in AD and MCI than in CN. Whether increased VRSs can be reliably used to aid in AD diagnosis warrants further investigation.

Efficacy, tolerability, and biomarker analyses from a phase III, randomized, placebo-controlled, parallel group study of gefitinib as maintenance therapy in patients with locally advanced or metastatic non-small cell lung cancer (NSCLC; INFORM; C-TONG 0804)

LBA7511

Background: INFORM (a phase III, randomized, multicenter, parallel group study; NCT00770588 ) investigated the efficacy, safety and tolerability of gefitinib (G) vs. placebo (P) as maintenance therapy in pts with locally advanced/metastatic NSCLC following standard first-line platinum based chemotherapy. Methods: Pts (≥18 years, with stage IIIB/IV NSCLC and WHO performance status 0-2) had completed 4 cycles of first-line platinum based doublet chemotherapy without progression/unacceptable toxicity. Pts were randomized 1:1 to G 250mg/day or P on discontinuation of first-line therapy. Progression-free survival (PFS; primary endpoint) was assessed in the intent to treat population (Cox proportional hazards adjusted for histology [adenocarcinoma vs. non-adenocarcinoma], smoking status [never-smoker vs. smoker], EGFR mutation status [positive vs. negative vs. unknown] and best response to first-line chemotherapy [complete response/partial response vs. stable disease]). PFS was considered superior with gefitinib if the G:P hazard ratio (HR) upper confidence interval (CI) was <1.00. Secondary endpoints included overall survival (OS), objective response rate, disease control rate, symptom improvement and tolerability. Results: 296 pts (n=148 G, n=148 P) were randomized (27 centers in china; 26 September 2008-10 August 2009). PFS data cutoff on 24 January 2011. Median duration of follow-up was 16.8 months: 91% pts progressed; 59% deaths. Demography was balanced between treatments; overall, 54.1% pts were never-smokers, 70.6% had adenocarcinoma, and 40.9% were female. For G vs. P, PFS HR=0.42; 95% CI 0.32-0.54; p<0.0001; median PFS 4.8 vs. 2.6 months. Most common AEs (any grade) with G were rash (49.7%), diarrhea (25.2%), and ALT increase (21.1%) which were generally mild/moderate. Overall incidence of serious AEs: G (6.8%); P (3.4%). Other secondary endpoint data (including OS and biomarkers) will be presented. Conclusions: PFS was significantly longer with G compared with P as maintenance therapy in Chinese patients with locally advanced NSCLC.