Diagnostic criteria, pathogenesis, and precautionary measures for severe renal damage linked with heart surgery: a retrospective analysis

Background: Heart surgery (HS) complications such as renal damage (RD), which is a frequent and major consequence, are linked to higher mortality and morbidity rates as well as a significant financial burden. Several different pathophysiological ideas might explain the multifaceted complexity of the HS-RD pathogenesis. Aim: The purpose of this research is to identify RD after HS and to evaluate the results of diagnostic criteria, pathogenesis, and preventative measures. Methods: This retrospective analysis of HS patients examined the occurrence and impact of several definitions of RD, Renal Damage Network (RDN), and Kidney Disease: Improving Global Outcomes (KDIGO) or risk, injury, failure, loss, and end-stage kidney disease (RIFLE). We also defined transient RD and sustained RD. Results: RIFLE-Risk had the greatest positive probability ratio of every definition, continued with sustained RD (positive likelihood ratio = 2.27) for the best definition. 39 patients with KDIGO RD and all 80 patients having late RD were excluded from the RD defined by RDN criteria. Conclusion: The pathogenesis, definition, diagnosis, and preventative measures of RD in HS patients are discussed in this article. Based on the capacity to forecast short-term mortality, the risk was shown to be the most accurate definition of RD, followed by injury, failure, loss, and end-stage RD.

Chaperone-mediated autophagy promotes PCa survival during ARPI through selective proteome remodeling

The androgen receptor (AR) plays an important role in PCa metabolism, with androgen receptor pathway inhibition (ARPI) subjecting PCa cells to acute metabolic stress caused by reduced biosynthesis and energy production. Defining acute stress response mechanisms that alleviate ARPI stress and therefore mediate prostate cancer (PCa) treatment resistance will help improve therapeutic outcomes of patients treated with ARPI. We identified the up-regulation of chaperone-mediated autophagy (CMA) in response to acute ARPI stress, which persisted in castration-resistant PCa (CRPC); previously undefined in PCa. CMA is a selective protein degradation pathway and a key stress response mechanism up-regulated under several stress stimuli, including metabolic stress. Through selective protein degradation, CMA orchestrates the cellular stress response by regulating cellular pathways through selective proteome remodeling. Through broad-spectrum proteomic analysis, CMA coordinates metabolic reprogramming of PCa cells to sustain PCa growth and survival during ARPI; through the upregulation of mTORC1 signaling and pathways associated with PCa biosynthesis and energetics. This not only promoted PCa growth during ARPI, but also promoted the emergence of CRPC in-vivo. During CMA inhibition, PCa metabolism is compromised, leading to ATP depletion, resulting in a profound anti-proliferative effect on PCa cells, and is enhanced when combined with ARPI. Furthermore, CMA inhibition prevented in-vivo tumour formation, and also re-sensitized enzalutamide-resistant cell lines in-vitro. The profound anti-proliferative effect of CMA inhibition was attributed to cell cycle arrest mediated through p53 transcriptional repression of E2F target genes. In summary, CMA is an acute ARPI stress response mechanism, essential in alleviating ARPI induced metabolic stress, essential for ensuring PCa growth and survival. CMA plays a critical role in the development of ARPI resistance in PCa.

Longitudinal evaluation of plasma miR371 to detect minimal residual disease and early relapse of germ cell tumors

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Background: Active surveillance is routinely recommended to manage patients (pts) with clinical stage I (CSI) germ cell testicular tumors (GCT), the most common presentation of newly diagnosed GCT. Circulating plasma miR371a-3p (miR371) has shown high sensitivity and specificity in pts with metastatic non teratoma GCT or in pts with clinically detectable testicular GCT prior to orchiectomy. However, limited data are available about this biomarker accuracy to detect minimal residual disease post-orchiectomy in pts on active surveillance for early stage disease. Methods: CSI GCT pts with available plasma samples after radical orchiectomy enrolled in the British Columbia provincial biobank research program were selected for this study. RT-PCR was used for qualitative miR371 analysis. Sensitivity, specificity, negative and positive predictive values (NPV, PPV) and AUC in predicting tumor recurrence were evaluated for miR371 and compared to the same operating characteristics of current gold standard diagnostic tests. Relapse free survival (RFS) was correlated to post-orchiectomy miR371 (positive or negative) status. Fisher’s exact test was used to evaluate the sensitivity and specificity, unpaired t-test for comparison of miR371 expression. RFS was calculated using the Kaplan-Meier method, and differences between groups were estimated using the log rank test, 2-sided and with 5% significance threshold. Results: With a median follow-up of 41 months, 101 pts with CSI GTCwere included, of whom 35 (34.6%) experienced a disease relapse during the follow-up. miR371 was positive in 22/35 (62.8%) of the relapsed pts. miR371 positivity preceded clinical evident disease by a median of 3 months (range: 1-12 months).The specificity and PPV were 100% (95% CI: 94.5 - 100 for both), sensitivity 62.8% (95% CI: 44.9 - 78.5), NPV 83.5% (95% CI: 76.7 - 88.6) and AUC 0.81 (95% CI: 0.71 - 0.91). No false positive results were observed. The RFS of the pts with positive post-orchiectomy miR371 was significantly shorter (median: 3.5 months vs. not reached; p<0.0001) compared to the pts with a negative post-orchiectomy miR371 (HR: 16.9; 95% CI: 2.1 - 135.7; p<0.0001). miR371 sensitivity correlated with tumor burden, time between tumor relapse and miRNA testing and histology (nonseminoma > seminoma). Conclusions: miR371 has high specificity and PPV in detecting GCT at an early stage and could be used to guide treatment selection after orchiectomy. Further studies, including the SWOG S1823 clinical trial, are ongoing or have been planned in this setting for validation of clinical utility.

Dynamic phase separation of the androgen receptor and its coactivators key to regulate gene expression

Numerous cancers, including prostate cancer (PCa), are addicted to transcription programs driven by specific genomic regions known as super-enhancers (SEs). The robust transcription of genes at such SEs is enabled by the formation of phase-separated condensates by transcription factors and coactivators with intrinsically disordered regions. The androgen receptor (AR), the main oncogenic driver in PCa, contains large disordered regions and is co-recruited with the transcriptional coactivator mediator complex subunit 1 (MED1) to SEs in androgen-dependent PCa cells, thereby promoting oncogenic transcriptional programs. In this work, we reveal that full-length AR forms foci with liquid-like properties in different PCa models. We demonstrate that foci formation correlates with AR transcriptional activity, as this activity can be modulated by changing cellular foci content chemically or by silencing MED1. AR ability to phase separate was also validated in vitro by using recombinant full-length AR protein. We also demonstrate that AR antagonists, which suppress transcriptional activity by targeting key regions for homotypic or heterotypic interactions of this receptor, hinder foci formation in PCa cells and phase separation in vitro. Our results suggest that enhanced compartmentalization of AR and coactivators may play an important role in the activation of oncogenic transcription programs in androgen-dependent PCa.

TP53 Alterations Are Associated With Poor Survival in Patients With Primary Mediastinal Nonseminoma Germ Cell Tumors

BACKGROUND

Primary mediastinal nonseminoma germ cell tumors (PMNSGCT) are a subgroup of nonseminoma germ cell tumors (GCT) with poor prognosis. In this study, PMNSGCT-specific genomic landscape was analyzed and correlated with clinical outcomes.

METHODS

DNA was extracted and sequenced from 28 archival tumor tissue of patients with mediastinal GCT (3 seminoma and 25 nonseminoma). Overall survival (OS) and association with gene alterations were estimated using the Kaplan-Meier and univariate Cox regression methods.

RESULTS

Three patients (11%) had a karyotype XXY, 17/28 (61%) tumor samples presented chromosome 12p amplification. Somatic mutations were detected in 19/28 (68%) samples. The most frequently mutated genes were: TP53 (13/28; 46%), KIT (5/28; 18%), and KRAS (5/28; 18%). Deleterious TP53 alterations were associated with significantly reduced overall survival (HR: 7.16; P = .012).

CONCLUSIONS

TP53 alterations are common in PMNSGCT and are associated with reduced overall survival, potentially underlying the poor sensitivity to chemotherapy observed in these patients.

Abstract 5729: Dynamic phase separation of the androgen receptor and its coactivators to regulate gene expression

Numerous cancers, including prostate cancer (PCa), have been shown to be addicted to transcription programs driven by specific genomic sites known as superenhancers (SEs). Recently, it has been proposed that the robust transcription of genes at such SEs is enabled by the formation of phase-separated condensates by transcription factors and coactivators with intrinsically disordered regions. The androgen receptor (AR), the main oncogenic driver in PCa, contains large disordered regions and is co-recruited with the transcriptional coactivator MED1 to SEs in androgen-dependent prostate cancer cells, thereby promoting oncogenic transcriptional programs. In this work, we show that AR-rich, liquid-like foci form in prostate cancer models upon androgen stimulation. We reveal that foci formation correlates with AR transcriptional activity, which can be modulated by changing cellular foci content genetically or chemically. We also demonstrate that the transcriptional coactivator MED1 plays an essential role in the formation of transcriptionally active AR-rich foci and that AR antagonists that block cofactor recruitment or DNA binding hinder foci formation and thus AR transcriptional activity. The liquid like properties of the condensates were also validated in-vitro by using recombinant AR protein. Using clinical specimens, we detected the interaction between AR and MED1 in advanced forms of prostate cancer and not in benign tissues. These results suggest that enhanced compartmentalization of AR and coactivators at SEs may play an important role in the activation of oncogenic transcription programs in androgen-dependent PCa. A better understanding of the assembly and the regulation of these AR-rich compartments may provide novel therapeutic options for PCa by targeting downstream events of androgen activation and DNA binding of AR.

Citation Format: Fan Zhang, Maitree Biswas, Joseph Lee, Shreyas Lingadahalli, Samantha Wong, Christopher Wells, Neetu Saxena, Bei Sun, Ana K. Parra-Nuñez, Christophe Sanchez, Jane Foo, Novia Chan, Lauren Ung, Nabeel Khan, Umut Berkay Altıntaş, Jennifer M. Bui, Yuzhuo Wang, Ladan Fazli, Paul S. Rennie, Nathan Lack, Artem Cherkasov, Martin E. Gleave, Joerg Gsponer, Nada Lallous. Dynamic phase separation of the androgen receptor and its coactivators to regulate gene expression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5729.

Abstract 3881: Immune profiling of advanced prostate cancer harboring homologous recombination deficiency

Background: Most patients with metastatic prostate cancer (mPCa) do not derive benefit from immune checkpoint inhibitors (ICI). Homologous recombination deficiency (HRD) affects up to 6-8% of patients with localized PCa and up to 30% of patients with metastatic castrate-resistant prostate cancer (mCRPC) and is predictive of response to PARP inhibitors. The potential activity of ICI in this subset of patients is unknown and the tumor microenvironment (TME) associated with HRD is poorly understood. We used PCa tumors of patients with known HRD alterations as a model to study clinically relevant, therapeutically targetable drivers of tumor immunology.

Methods: Archival tumor tissue of patients with known germline or somatic HRD alterations enrolled in our institutional GU Biobank (n=13) was used for immunohistochemistry to evaluate the expression of the following immune markers in both tumor cells (TC) and stromal lymphocytes (SL): CD8, adenosine receptor 2a (A2aR), GAL9, IL-2, LAG3, PD-L2, and TIM-3. The same markers were analyzed in untreated (n=104), neoadjuvant hormone therapy treated (NHT) (n=16), neuroendocrine (NEPC) (n=41) and CRPC (n=22) tissue. Two-tailed t-test and Pearson R correlations were performed for analysis.

Results: Among screened HRD alterations,BRCA1/2 were the most frequently identified (BRCA1/2n=6, FANCCn=1, FANCD2=2, PALB2=1, CDK12n=1, ATRn=2). CD8+ cells were primarily localized in the stroma of HRD cohort specimens and were more abundant compared to NEPC (p≤ 0.05) and untreated tumors (p≤0.01). The HRD cohort had higher levels of A2aR, in TC and SL (p≤0 .0001 for both) and higher levels of PD-L2 in TC (p≤0.0001) compared to all other cohorts and in the SL (p≤0.05) compared to untreated, CRPC and NEPC cohorts. Lower levels of LAG3 were found in the HRD cohort TC compared to NHT cohort, and in HRD cohort SL compared to all cohorts (p≤0.0001 for both). There was no difference in TIM-3 or GAL9 expression.

Conclusions: Evaluation of stromal and tumor cell immune profiling indicates that compared to other subtypes, PCa with HRD alteration have a unique immune profile abundant in CD8+ cell, and PD-L2 and A2aR expression. Not only does this indicate an immune active TME but also identifies therapeutically actionable immunotherapeutic pathways which may render clinical benefit in this patient population.

Citation Format: Maryam Soleimani, Sonia Kung, Neetu Saxena, Ladan Fazli, Lucia Nappi. Immune profiling of advanced prostate cancer harboring homologous recombination deficiency [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3881.

Immune profiling of advanced prostate cancer harboring homologous recombination deficiency

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Background: Most patients with metastatic prostate cancer (mPCa) do not derive benefit from immune checkpoint inhibitors (ICI). Homologous recombination deficiency (HRD) affects up to 30% of patients with metastatic castrate-resistant prostate cancer (mCRPC) and is predictive of response to PARP inhibitors. The potential activity of ICI in this subset of patients is unknown and the tumour microenvironment (TME) associated with HRD is poorly understood. We used mPCa tumours of patients with known HRD alterations as a model to study clinically relevant, therapeutically targetable drivers of tumour immunology. Methods: Archival tumor tissue of patients with known germline or somatic HRD alterations enrolled in our institutional GU Biobank (n = 13) was used for immunohistochemistry to evaluate the expression of the following immune markers in both tumour cells (TC) and stromal lymphocytes (SL): CD8, adenosine receptor 2a (A2aR), GAL9, IL-2, LAG3, PD-L2, and TIM-3. The same markers were analyzed in untreated (n = 104), and neoadjuvant hormone therapy treated (NHT) (n = 16) tissue. Two-tailed t-test and Pearson R correlations were performed for analysis. Results: Among screened HRD alterations, BRCA1/2 were the most frequently identified ( BRCA1/2 n = 6, FANCC n = 1, FANCD2 n = 2, PALB2 n = 1, CDK12 n = 1, ATR n = 2). CD8+ cells were primarily localized in the stroma of HRD cohort specimens rather than in the glandular epithelia. The HRD cohort had higher levels of A2aR, in TC and SL (p≤0.0001 for both). When compared to the untreated cohort, PD-L2 levels were higher in SL of the HRD cohort (p≤0.05) while lower in the TC (p≤0.01). Lower levels of LAG3 were found in the HRD cohort TC compared to NHT cohort (p≤0.01). There were significantly lower levels of GAL9 in the TC of the HRD cohort compared to untreated (p < 0.0001) tumours. There were no differences in TIM-3 levels between the cohorts. Conclusions: Evaluation of stromal and tumour cell immune profiling indicates that compared to other subtypes, mPCa with HRD alteration have a unique immune profile abundant in CD8+ cell, and high in PD-L2 and A2aR expression. Not only does this indicate an immune active TME but also identifies therapeutically actionable pathways which may render clinical benefit in this patient population.

Regulation of AR mRNA translation in response to acute AR pathway inhibition

We report a new mechanism of androgen receptor (AR) mRNA regulation and cytoprotection in response to AR pathway inhibition (ARPI) stress in prostate cancer (PCA). AR mRNA translation is coordinately regulated by RNA binding proteins, YTHDF3 and G3BP1. Under ambient conditions m6A-modified AR mRNA is bound by YTHDF3 and translationally stimulated, while m6A-unmodified AR mRNA is bound by G3BP1 and translationally repressed. When AR-regulated PCA cell lines are subjected to ARPI stress, m6A-modified AR mRNA is recruited from actively translating polysomes (PSs) to RNA-protein stress granules (SGs), leading to reduced AR mRNA translation. After ARPI stress, m6A-modified AR mRNA liquid–liquid phase separated with YTHDF3, while m6A-unmodified AR mRNA phase separated with G3BP1. Accordingly, these AR mRNA messages form two distinct YTHDF3-enriched or G3BP1-enriched clusters in SGs. ARPI-induced SG formation is cell-protective, which when blocked by YTHDF3 or G3BP1 silencing increases PCA cell death in response to ARPI stress. Interestingly, AR mRNA silencing also delays ARPI stress-induced SG formation, highlighting its supportive role in triggering this stress response. Our results define a new mechanism for stress adaptive cell survival after ARPI stress involving SG-regulated translation of AR mRNA, mediated by m6A RNA modification and their respective regulatory proteins.

Plasma exosome microRNA-155 expression in patients with metastatic renal cell carcinoma treated with immune checkpoint inhibitors: A potential biomarker of response to systemic therapy

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Background: The search for a reliable predictive biomarker of response to immune checkpoint-based therapy (ICBT) remains a critically unmet need in the management of metastatic renal cell carcinoma (mRCC). We sought to evaluate the biomarker potential of plasma exosome microRNAs (miRNAs) implicated in RCC and in augmentation of the tumour microenvironment (TME) for such a role. Methods: Eleven miRNAs that are over-expressed in RCC and/or immune-associated were evaluated in 40 patients with mRCC (prior to initiating ICBT) and in 30 healthy volunteers. Exosomes were extracted from 500 uL of plasma and were used for miRNAs extraction. MiRNAs expression was evaluated by RT-PCR. Cycle threshold values were normalized to miR-30-3b, and the relative quantity of the expression (RQ) was compared to those of healthy volunteers and calculated using the 2ΔΔCt method. Mann-Whitney U test was used to evaluate the expression of miRNAs between mRCC pts and healthy volunteers according to best response to first line ICBT between responders (n = 27) v non-responders (n = 13). The cut-off value of significant expression was established by Youden’s index. Responders were defined as those patients experiencing complete response, partial response or stable disease and non-responders were those who experienced progressive disease. Results: The most common first line ICBT was nivolumab + ipilimumab (n = 32), followed by pembrolizumab + axitinib (n = 5), and avelumab + axitinib (n = 3). A significantly higher expression of miRNA-1233 (median 1.85 v 0.81 p = 0.008) and miRNA-155 [miR-155] (3.69 v 0.21 p = 0.006) were found in patients compared to healthy volunteers. Higher miR-155 expression was associated with higher Fuhrman grade (p = 0.002). There was no association with other clinical prognostic factors. MiR-155 was expressed at a significantly lower level in responders than in non-responders (median 0.61 v 35.29, p = 0.042). Response rate amongst patients with low and high expression of miR-155 (RQ ≤ 2.5) was statistically different (p = 0.042) and 84.2% of the pts with low miR-155 expression responded to the treatment. Conclusions: Lower expression of miR-155 was associated with response to ICBT in patients with mRCC. Functionally, miR-155 is involved in regulation and modulation of the TME. These results underscore the need for further work in this area to elucidate the role of this and other miRNAs as biomarkers of response in mRCC.

Androgen receptor (AR) antagonism triggers acute succinate-mediated adaptive responses to reactivate AR signaling

Treatment-induced adaptive pathways converge to support androgen receptor (AR) reactivation and emergence of castration-resistant prostate cancer (PCa) after AR pathway inhibition (ARPI). We set out to explore poorly defined acute adaptive responses that orchestrate shifts in energy metabolism after ARPI and identified rapid changes in succinate dehydrogenase (SDH), a TCA cycle enzyme with well-known tumor suppressor activity. We show that AR directly regulates transcription of its catalytic subunits (SDHA, SDHB) via androgen response elements (AREs). ARPI acutely suppresses SDH activity, leading to accumulation of the oncometabolite, succinate. Succinate triggers calcium ions release from intracellular stores, which in turn phospho-activates the AR-cochaperone, Hsp27 via p-CaMKK2/p-AMPK/p-p38 axis to enhance AR protein stabilization and activity. Activation of this pathway was seen in tissue microarray analysis on prostatectomy tissues and patient-derived xenografts. This adaptive response is blocked by co-targeting AR with Hsp27 under both in vitro and in vivo studies, sensitizing PCa cells to ARPI treatments.

Longer follow-up data of circulating miR371a-3p expression across the spectrum of germ cell tumors (GCT)

379

Background: miR371a-3p (miR371) is overexpressed in seminoma (S) and nonseminoma (NS) active germ cell malignancy (aGCM) and easily detectable in blood. We previously described1 a remarkably high accuracy of miR371 in detecting aGCM in early and advanced stages germ cell tumor (GCT) patients (pts). We here present the updated miR371 expression data with a longer follow-up, particularly relevant to assess miR371 clinical utility to predict GCT relapse in clinical stage I (CSI) and stage IIA pts. Methods:119 samples from 99 pts enrolled in the GU biobank program at the British Columbia Cancer – Vancouver were analyzed. The pts were divided according to their risk of aGCM in low (CSIA NS and CSI S), moderate (CSIB NS, stage IIA markers negative/low elevated S and NS), and high risk (definitively metastatic aGCM) groups. Blood of the low and moderate risk pts was collected post orchiectomy and at the time of the clinical relapse; prior to/post-chemotherapy in the high risk group. Plasma miR371 expression was evaluated by RT-PCR and quantified by ΔΔCT method. Sensitivity, specificity, negative and positive predictive values (NPV, PPV) and AUC of the ROC curve were analyzed. Results: Five (2 moderate - 3 low risks) pts were lost at follow-up and 1 high risk pt had deceased. Overall, 113 samples (50, 36, 27 in the low, moderate, and high risk groups, respectively) were analyzed. The median follow-up from study entry was 30 (6-51), 28 (20-52), and 29 (7-53) months for the low, moderate and high risk, respectively. Seven more relapses occurred: 4 in the low risk (3 S and 1 NS) and 3 in the moderate risk groups (2 NS and 1 S). miR371 was found falsely negative post-orchiectomy in 4 pts and truly negative in 3 relapsed pts (2 pure teratoma and 1 unconfirmed relapse). Serial analysis of the false negative relapsed pts showed that miR371 became detectable at the time of clinical relapse. The operating characteristics of miR371 are summarized in the table below. Conclusions: Our follow-up has exceeded the expected time of relapse even in the low risk pts. The high accuracy of miR371 in detecting aGCM was confirmed with a longer follow up. However, the few false negatives in relapsed pts and the serial analysis suggest a lack of sensitivity in the detection of microscopic disease post-orchiectomy with the current methodology while miR371 high sensitivity was confirmed in presence of radiologic measurable disease (≥ 1 cm). The definitive operating characteristics of miR371 post-orchiectomy and during the follow-up of stages I/ IIA pts will be prospectively validated by the S1823 study that is actively recruiting pts. [Table: see text]

Plasma exosome microRNAs in patients with advanced renal cell carcinoma treated with nivolumab and ipilimumab: Potential biomarkers of response to therapy

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Background: There is a critical unmet need for predictive biomarkers in the management of metastatic renal cell carcinoma (mRCC). We sought to quantify plasma exosome microRNAs (miRNAs) and correlate with response to first line nivolumab and ipilimumab (N/I) to potentially serve as such a biomarker. Methods: We evaluated the expression of 11 miRNAs in 19 patients with mRCC (prior to initiation of N/I) and in 32 healthy volunteers. Exosomes were extracted from 500 uL of plasma (qEV original, Izon Science) and once confirmed, were used for miRNAs extraction. MiRNAs expression was evaluated by real time polymerase chain reaction using a TaqMan miRNA assay (Applied Biosystems). The relative quantity of each miRNA in patients was compared to healthy volunteers. The expression of each miRNA was correlated to the best response to N/I, categorizing patients as either responders or non-responders. Results: Clinical characteristics are summarized in the table below. Median age at the start of systemic therapy was 64.3 years. MiR200b demonstrated a significantly higher expression in mRCC patients than in healthy volunteers (unpaired t-test; p=0.04). We observed a variable pattern of miRNA expression based on response to N/I. Although not statistically significant, 4 miRNA (miR138, 155, 200b, 221) were upregulated in non-responders, while two (miR200a and 497) were upregulated in responders. Of note, the only patient to achieve a complete response had the lowest expression of miR138 and the highest expression of miR497. Conclusions: Although preliminary and limited by a small number of patients, these initial observational results are promising and suggest a potential role for miRNAs as predictive biomarkers in mRCC. MiR138 and 497 are known to regulate CTLA-4 and PD-L1, respectively. We speculate that these miRNA are potentially involved in response to immune checkpoint therapy. Ongoing work in evaluating expression of these and other miRNAs in blood and in tissue along with clinical correlation continues. [Table: see text]

G3BP1-linked mRNA partitioning supports selective protein synthesis in response to oxidative stress

Cells limit energy-consuming mRNA translation during stress to maintain metabolic homeostasis. Sequestration of mRNAs by RNA binding proteins (RBPs) into RNA granules reduces their translation, but it remains unclear whether RBPs also function in partitioning of specific transcripts to polysomes (PSs) to guide selective translation and stress adaptation in cancer. To study transcript partitioning under cell stress, we catalogued mRNAs enriched in prostate carcinoma PC-3 cell PSs, as defined by polysome fractionation and RNA sequencing (RNAseq), and compared them to mRNAs complexed with the known SG-nucleator protein, G3BP1, as defined by spatially-restricted enzymatic tagging and RNAseq. By comparing these compartments before and after short-term arsenite-induced oxidative stress, we identified three major categories of transcripts, namely those that were G3BP1-associated and PS-depleted, G3BP1-dissociated and PS-enriched, and G3BP1-associated but also PS-enriched. Oxidative stress profoundly altered the partitioning of transcripts between these compartments. Under arsenite stress, G3BP1-associated and PS-depleted transcripts correlated with reduced expression of encoded mitochondrial proteins, PS-enriched transcripts that disassociated from G3BP1 encoded cell cycle and cytoprotective proteins whose expression increased, while transcripts that were both G3BP1-associated and PS-enriched encoded proteins involved in diverse stress response pathways. Therefore, G3BP1 guides transcript partitioning to reprogram mRNA translation and support stress adaptation.

Paternally Expressed Gene 10 (PEG10) Promotes Growth, Invasion, and Survival of Bladder Cancer

Paternally expressed gene 10 (PEG10) has been associated with neuroendocrine muscle-invasive bladder cancer (MIBC), a subtype of the disease with the poorest survival. In this work, we further characterized the expression pattern of PEG10 in The Cancer Genome Atlas database of 412 patients with MIBC, and found that, compared with other subtypes, PEG10 mRNA level was enhanced in neuroendocrine-like MIBC and highly correlated with other neuroendocrine markers. PEG10 protein level also associated with neuroendocrine markers in a tissue microarray of 82 cases. In bladder cancer cell lines, PEG10 expression was induced in drug-resistant compared with parental cells, and knocking down of PEG10 resensitized cells to chemotherapy. Loss of PEG10 increased protein levels of cell-cycle regulators p21 and p27 and delayed G₁-S-phase transition, while overexpression of PEG10 enhanced cancer cell proliferation. PEG10 silencing also lowered levels of SLUG and SNAIL, leading to reduced invasion and migration. In an orthotopic bladder cancer model, systemic treatment with PEG10 antisense oligonucleotide delayed progression of T24 xenografts. In summary, elevated expression of PEG10 in MIBC may contribute to the disease progression by promoting survival, proliferation, and metastasis. Targeting PEG10 is a novel potential therapeutic approach for a subset of bladder cancers.

Ivermectin inhibits HSP27 and potentiates efficacy of oncogene targeting in tumor models

HSP27 is highly expressed in, and supports oncogene addiction of, many cancers. HSP27 phosphorylation is a limiting step for activation of this protein and a target for inhibition, but its highly disordered structure challenges rational structure-guided drug discovery. We performed multistep biochemical, structural, and computational experiments to define a spherical 24-monomer complex composed of 12 HSP27 dimers with a phosphorylation pocket flanked by serine residues between their N-terminal domains. Ivermectin directly binds this pocket to inhibit MAPKAP2-mediated HSP27 phosphorylation and depolymerization, thereby blocking HSP27-regulated survival signaling and client-oncoprotein interactions. Ivermectin potentiated activity of anti-androgen receptor and anti-EGFR drugs in prostate and EGFR/HER2-driven tumor models, respectively, identifying a repurposing approach for cotargeting stress-adaptive responses to overcome resistance to inhibitors of oncogenic pathway signaling.

SDHB-Deficient Cancers: The Role of Mutations That Impair Iron Sulfur Cluster Delivery

BACKGROUND

Mutations in the Fe-S cluster-containing SDHB subunit of succinate dehydrogenase cause familial cancer syndromes. Recently the tripeptide motif L(I)YR was identified in the Fe-S recipient protein SDHB, to which the cochaperone HSC20 binds.

METHODS

In order to characterize the metabolic basis of SDH-deficient cancers we performed stable isotope-resolved metabolomics in a novel SDHB-deficient renal cell carcinoma cell line and conducted bioinformatics and biochemical screening to analyze Fe-S cluster acquisition and assembly of SDH in the presence of other cancer-causing SDHB mutations.

RESULTS

We found that the SDHBR46Q mutation in UOK269 cells disrupted binding of HSC20, causing rapid degradation of SDHB. In the absence of SDHB, respiration was undetectable in UOK269 cells, succinate was elevated to 351.4 ± 63.2 nmol/mg cellular protein, and glutamine became the main source of TCA cycle metabolites through reductive carboxylation.Furthermore, HIF1α, but not HIF2α, increased markedly and the cells showed a strong DNA CpG island methylatorphenotype (CIMP). Biochemical and bioinformatic screening revealed that 37% of disease-causing missense mutations in SDHB were located in either the L(I)YR Fe-S transfer motifs or in the 11 Fe-S cluster-ligating cysteines.

CONCLUSIONS

These findings provide a conceptual framework for understanding how particular mutations disproportionately cause the loss of SDH activity, resulting in accumulation of succinate and metabolic remodeling in SDHB cancer syndromes.

Abstract P1-07-04: A novel bioactive approach to inhibit leptin-induced epithelial-mesenchymal transition in breast cancer

Introduction: Molecular effects of obesity, a well-established risk factor for breast cancer progression, are mediated by adipocytokine leptin. Recent studies from our lab reveal that leptin induces epithelial-mesenchymal transition (EMT) and tumorsphere formation via concomitant activation of Akt/GSK3b and MTA1/Wnt1 signaling axes leading to β catenin activation. Given the important role of leptin in breast cancer growth and metastasis, novel strategies to antagonize biological effects of leptin are much desired. We showed previously that honokiol, a bioactive polyphenol from Magnolia grandiflora, inhibits breast carcinogenesis. The present study provides first evidence for the efficacy of honokiol against oncogenic effects of leptin including EMT.

Methods: Efficacy of honokiol to inhibit oncogenic effects of leptin was evaluated by using clonogenicity, anchorage–independent growth, matrigel-invasion and spheroid-migration assays. RT-PCR, western blot and immunofluorescence analyses were used to examine the molecular changes associated with EMT as well as underlying molecular pathways. Functional importance of MTA1/Wnt1/ β catenin axis was examined by using overexpression, phospho-deficient constructs and specific inhibitors. Finally, mouse xenografts, immuniohistochemical, RT-PCR and western blot analysis of tumors was used.

Results: Honokiol treatment circumvents leptin-induced EMT-associated phenotypic changes. A biochemical hallmark of EMT is loss of expression of epithelial markers with a concurrent increase in mesenchymal marker expression. Honokiol elicits increased expression of E-cadherin, occludin and keratin-18 (epithelial markers) and decreased expression of vimentin, fibronectin and N-cadherin (mesenchymal markers) in leptin-treated cells providing molecular evidence for reversal of EMT. Honokiol also inhibits expression and nuclear translocation of transcriptional effectors of EMT; Snail, Slug, Zeb1 and Zeb2. Analysis of underlying molecular mechanisms reveals that Honokiol effectively inhibits leptin-induced MTA1/Wnt1/ β catenin axis. Furthermore, using nontoxic doses of honokiol, we show that honokiol treatment effectively inhibits leptin-induced breast tumorigenesis in vivo. Analysis of breast tumors show that honokiol treatment reverses leptin-associated signaling (MTA1/Wnt1/ β catenin axis) along with decreased expression of mesenchymal markers and increased expression of epithelial markers.

Conclusions: In this study, we demonstrate for the first time that HNK is able to abolish leptin-induced EMT and provide in vitro and in vivo evidence for the integral role of a previously unrecognized crosstalk between honokiol and MTA1/Wnt1/ β catenin axis. Thus, HNK may be used as a non-toxic and non-endocrine rational therapeutic strategy for breast carcinoma in obese patients with high leptin levels.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P1-07-04.

Abstract P2-09-12: Withaferin A-mediated inhibition of breast carcinoma involves concomitant activation of CHOP and Elk1 via ERK/ribosomal S6 kinase (RSK) signaling axis regulating death receptor 5 expression

Introduction: Despite significant progress towards screening efforts and targeted therapies, breast cancer is still a leading cause of cancer-related mortality among women. Novel therapeutic strategies are clearly needed for effective targeting of breast cancer. Natural products continue to generate interest for identification of potential chemopreventive and therapeutic agents. Withaferin A (WFA) is a bioactive small molecule that has been proposed as a new-generation molecule capable of eliciting growth inhibitory effect on cancer cells. The molecular mechanisms by which WFA mediates inhibition of breast cancer remain elusive. The present study was designed to systematically elucidate the underlying mechanisms by which WFA inhibits growth and metastatic potential of breast cancer cells.

Methods: Efficacy of WFA treatment on cell growth was evaluated by using clonogenicity, and anchorage–independent growth. Western blot and immunofluorescence analysis were used to examine activation of ERK/RSK (extracellular signal-regulated kinase/ ribosomal S6 kinase) and downstream signaling axes. Functional importance of ERK/RSK and CHOP (C/EBP homologous protein) in the biologic effects of WFA was examined by using overexpression, phospho-deficient constructs and specific inhibitors. Finally, mouse xenografts, immunohistochemical, RT-PCR and western blot analysis of tumors were used.

Results: Analysis of the underlying molecular mechanisms revealed that WFA treatment induced phosphorylation of RSK2 in an ERK-dependent manner. Further, WFA-induced ERK/RSK signaling resulted in concomitant upregulation of CHOP and Elk-1(ETS-like transcription factor 1). By using ERK1/2 siRNA and FMK-MEA inhibitor, we found that ERK/RSK signaling axis is required for WFA-mediated modulation of CHOP and Elk-1. Intriguingly, we discovered that WFA triggers the nuclear translocation of CHOP and Elk1 resulting in transcriptional upregulation of Death Receptor protein (DR5). CHOP and Elk1 overexpression potentiated while phospho-deficient Elk-1 inhibited WFA-induced DR5 expression exhibiting that CHOP/Elk-1 cooperatively regulate DR5 expression. Furthermore, using nontoxic doses of WFA, we showed that WFA treatment effectively inhibited breast tumorigenesis in vivo. Analysis of WFA-treated breast tumors showed increased activation of ERK/RSK axis and DR5 along with higher nuclear accumulation of CHOP and Elk-1.

Conclusion: These data provided first in vitro and in vivo evidence of the integral role of a previously unrecognized crosstalk between WFA and ERK/RSK and CHOP/Elk-1 axes in breast tumor growth inhibition. WFA treatment could potentially be a rational therapeutic strategy for breast carcinoma.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-09-12.

Pineal, Photoperiod and Gonadal Function in the Indian Palm Squirrel, Funambulus pennanti

Effects of morning and evening injections of pineal 5-methoxyindoles (MI), melatonin (aMT) and 5-methoxytryptamine (MT), for 60 continuous days, were observed on the testes of sham-operated (SO) and pinealectomized (Px) Indian palm squirrel, Funambulus pennanti maintained under different photoperiods during the gonad active phase. Long photoperiod (LP) of 14L:10D appeared stimulatory to the testes and caused a significant increase in the weight and seminiferous tubule diameter of both SO and Px animals, as compared to the animals under natural day-length (NDL). Short photoperiod (SP) of 10L:14D had an inhibitory influence and reduced the testes weight and its tubule diameter. aMT and MT injections during evening hours significantly reduced testes weight and tubule diameter of SO and Px animals under NDL, LP and SP. However morning injections, under all conditions, were without any significant effect. The results suggest an inhibitory effect of aMT and MT, under above photoperiodic conditions, on the testes of this tropical mammal. The time of administration of the MI is important in the expression of the effect.

P3-07-29: Validating the Lymph Node Ratio as a Prognostic Indicator among South East Asian Breast Cancer Patients

Background: Several studies in Caucasian settings have suggested that the lymph node ratio (LNR, i.e. the ratio of the number of positive nodes to the total number of nodes excised) is a superior prognostic indicator for breast cancer as compared to the absolute number of nodes involved (pN stage). This study validates the prognostic performance of LNR in the South East Asian setting.

Methods: All patients diagnosed with non-metastatic invasive breast cancer at the National University Hospital (Singapore) or University of Malaya Medical Center (Kuala Lumpur) between 1990 and 2007 and with information on axillary nodes removed and involved were included for analysis (n = 1589). Multivariate Cox regression analysis was performed to evaluate the prognostic value of the LNR [low (&gt; 0 and &lt;0.2), intermediate (0.2 to 0.65) and high risk (&gt;0.65 to 1)] and pN staging [pN1, pN2 and pN3] for all cause mortality. Patients staged pN0/LNR 0 were excluded from analysis.

Results: According to the LNR classification, 758 patients were categorized as low risk, 574 as intermediate risk and 257 as high risk LNR. For classic pN staging, 879 were pN1, 447 pN2 and 263 pN3. Women in the intermediate risk category (0.2 to 0.65) had a 1.5 fold increased risk of death [Adjusted hazard ratio [HRadj] of 1.5 (95%CI, 1.2 to 1.9]), and women with high risk (&gt;0.65 to 1) LNR had a 3.2 fold increased risk of death [HRadj of 3.2 (95%CI, 2.6 to 4.1)] as compared to the low risk women (&gt;0 and &lt;0.2). Similarly, women with pN2 disease had a 1.9 fold increased risk of death [HRadj of 1.9 (95%CI, 1.5 to 2.4)], and women with pN3 disease had 3.1 fold increased risk of death [HRadj 3.1 (95%CI, 2.5 to 3.9)] compared to pN1 patients.

Conclusion: Among South East Asian breast cancer patients, both the Lymph Node Ratio and the pN Staging system seem to be equally good at predicting all cause mortality.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P3-07-29.

P2-12-20: Adjuvant! Online Is Overoptimistic in Predicting Survival of Asian Breast Cancer Patients

Background

Adjuvant! Online is a free web-based tool which predicts 10-year breast cancer outcomes and efficacy of adjuvant therapy in patients with breast cancer. As its prognostic performance has only been validated in high income Caucasian populations, the model was validated in a middle income Asian setting.

Material and Methods: Within the University Malaya Hospital-Based Breast Cancer Registry, all 631 women receiving standard surgery for invasive non-metastatic breast cancer between 1993 and 2000 were identified. Calibration of Adjuvant! Online was evaluated by comparing the predicted 10-year overall survival with observed 10-year survival. Discrimination of the model was tested by receiver operating characteristic (ROC) analysis.

Results: For the entire cohort, Adjuvant! Online predicted 10 year survival (70.3%) was significantly higher than the observed 10 years survival (63.6 %) by a difference of 6.7% (95%CI: 3.0%- 10.4%). The model was especially overoptimistic in women under 40 years and in women of Malay ethnicity, where survival was overestimated by approximately 20% (95%CI: 9.8- 29.8%) and 15% (95%CI: 5.3−24.5%) respectively.

P5-14-10: Ethnic Differences in the Association between Tumor Size and Lymph Node Status among Breast Cancer Patients in South East Asia

Background: South East Asia consists of three major ethnic groups, i.e. Chinese, Malays and Indians. Previous work from our breast cancer research group showed that Malay ethnicity is an independent predictor of poor survival. In this study we evaluate whether (part of) these ethnic survival disparities may be due to ethnic differences in the association of tumor size and lymph node involvement.

Methods: We included all patients diagnosed with breast cancer at the National University Hospital (Singapore) and University of Malaya Medical Center (Kuala Lumpur) between 1990 and 2007, for whom information on tumor size and axillary lymph node status was available (n = 3805). Ethnic differences in the association between tumor size and lymph node involvement were studied and logistic regression analysis was performed to determine the independent effect of ethnicity on the association of tumor size and lymph node involvement.

Results: 1474 patients were categorized as T1 (&gt;0 to 2 cm), 1777 as T2 (2.1 to 5 cm) and 554 as T3 (&gt;5 cm). Within the small tumor size range (&gt;0 to 2 cm) the Malays were significantly more likely to present with node positive disease as compared to the other ethnic groups (36.9% as compared to 24.5% for Chinese and 25.9% for Indians, p value &lt;0.001). Similarly, for tumors measuring 2.1-5 cm, Malays were more likely than Chinese and Indians to have lymph node involvement (59.5%, 50.2% and 52.1%, respectively p value 0.016). After adjustment for age, Progesterone Receptor (PR) status, grade and treatment received, Malay ethnicity was an independent predictor of lymph node involvement, with adjusted Odds Ratio's of 1.4 (95% CI 1.0 to 2.1) for T1 tumors and 1.4 (95% CI 1.1 to 1.9) for T2 tumors compared to Chinese women.

Conclusion: Malay patients are more likely to present with lymph node metastasis especially for the small and midsized tumors as compared to the Chinese and Indians. This could reflect differences in tumor biology between the three ethnic groups with the Malays possibly having more aggressive disease than the others.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P5-14-10.

Abstract P3-11-13: Impact of Young Age on the Presentation, Management and Outcome of Breast Cancer in a Multi-Ethnic Asian Setting: Results from the Singapore-Malaysia Hospital-Based Breast Cancer Registry

Background: The proportion of very young women with breast cancer is high in Asia, ranging between 10% and 25%. Material and methods: Within the multi-institutional Singapore-Malaysia hospital-based breast cancer registry, we compared tumor characteristics, treatment and survival of very young (&lt;35 years; n=210) and older (35-55 years; n=2,152) breast cancer patients diagnosed between 1990 and 2007. Overall survival (OS)was estimated by Kaplan-Meier analysis. Cox regression analysis was used to compute hazard ratios (HR) after splitting follow-up time along the age-axis and calendar-time axis.

Results: Compared to older breast cancer patients, young patients presented with larger tumor (median diameter 25mm vs 30mm respectively: P&lt;0.001), and less estrogen receptor positive (54% vs 46% respectively: P&lt;0.01), and progesterone receptor positive tumors (57% vs 47%: P&lt;0.01). Young women were more likely to receive chemotherapy (70% vs 61%: P&lt;0.01), and less likely to be given hormone therapy (36% vs 57%: P&lt;0.001).

Among those with stage 0 to stage II disease, 5-year OS was 71.3% (95%CI: 61.7%-80.9%) in young patients and 85.6% (95%CI: 83.2%- 88.0%) in older women. After adjustment for stage, tumor profile and treatment, young patients had approximately 50% higher risk of death than their older counterparts (HR:1.46; 95% CI: 1.23-1.73). Ethnicity, tumor size, pathological lymph node staging, loco-regional therapy, and chemotherapy, were significant independent predictors of overall survival among young patients with breast cancer.

Conclusion: Asian women diagnosed at a very young age, present with less favorable tumor characteristics and stage distribution. They have a 50% higher risk of death following their disease, which is independent of their stage at diagnosis, tumor characteristics and treatment.

Abstract P3-13-03: Association between Ethnicity and Survival after Breast Cancer in a Multi-Ethnic Asian Setting: Results from the Singapore-Malaysia Hospital-Based Breast Cancer Registry

Background: Little is known on the impact of ethnicity on survival after breast cancer in the multi-ethnic Asian setting. Material and Methods: Using the multi-institutional Singapore-Malaysia hospital-based breast cancer registry, we investigated the association between ethnicity and risk of mortality after breast cancer in 3,366 patients diagnosed between 1990 and 2007 (Chinese: 77%, Malay: 15%, Indian: 8%). Kaplan-Meier analysis was used to estimate overall cumulative survival (OS). Multivariable hazard ratios (HR) adjusted for tumor and treatment characteristics were computed using Cox regression analysis after splitting follow-up time along the age-axis and calendar-time axis. Results: Malay patients presented at younger age compared to Chinese and Indians (47years vs 52years vs 53years, respectively, P&lt;0.001) with larger tumors (35mm vs 24mm vs 30mm, respectively, P&lt;0.001), and at later stages (TNM stage III or IV) (37% vs 23% vs 25%, respectively, P&lt;0.001). Malay women were least likely to have undergone surgery, and most likely to receive chemotherapy. Five-year OS was 71.9% (95% CI: 69.7%-74.1%) in Chinese, 47.2% (95%CI: 41.9%-52.5%) in Malays and 62.7% (56.0%- 69.4%) in Indians.

After adjustment for tumor and treatment characteristics, Malay patients had approximately 60% higher risk of death than the Chinese (HR:1.57; 95%CI:1.40-1.77). Indian ethnicity was not significantly associated with risk of mortality after breast cancer compared to Chinese (HR:1.12; 95%CI: 0.98-1.30).

Conclusion: In the Asian setting, Malay ethnicity seems to be associated with significantly poorer survival after breast cancer, independent of tumor and treatment profile. The underlying reasons for this association are unclear but may be explained by variations in susceptibility to treatment, co-morbidity and lifestyle after diagnosis of breast cancer.

Impact of Older Age on Presentation and Management of Breast Cancer in the Multi-Ethnic Population of Singapore

Background: Studies in Caucasian populations have shown that older breast cancer patients are less likely to be treated according to standard guidelines and that this under-treatment is strongly associated with impaired survival. In Asia, where population sizes and life expectancy rates are rising, the number of older women developing breast cancer is growing rapidly. This study aims to evaluate characteristics and treatment patterns of older breast cancer patients in the multi-ethnic population of Singapore, where breast cancer rates have tripled over the past three decades.Methods: This study includes all 2547 women, diagnosed with breast cancer between 1995 and 2006 at the National University Hospital in Singapore. Patients were classified into younger (&lt; 65 years, n=2220) and older (&gt;= 65 years, n=327). Differences in patient and tumor characteristics and treatment between older and younger age groups were explored using multivariate logistic regression models.Results: Even though older Singapore breast cancer patients had more favorable tumor characteristics than younger ones (better tumor differentiation, more often expressing estrogen and progesterone receptors), they presented significantly more often with stage III (adjusted Odds Ratio [ORadj] 1.57, 95%CI 1.0-2.4) and metastatic disease (ORadj 4.3, 95%CI 2.9-6.5). Elderly women were at increased risk not to receive breast surgery (ORadj 1.61, 95%CI 1.0-2.6) and axillary clearance (ORadj 1.74, 95%CI 1.2-2.6). In case of stage I disease, older women were significantly less likely than younger women to be treated with breast conserving surgery (ORadj 0.31, 95%CI 0.2-0.5).Conclusion: Similar to their Caucasian counterparts, older Asian breast cancer patients in Singapore are diagnosed at a later stage and receive less often standard treatment than younger women. Further studies are being undertaken to estimate the impact of these discrepancies on outcome.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 3078.

RACK-1 overexpression protects against goniothalamin-induced cell death

Goniothalamin, a styryllactone, has been shown to induce cytotoxicity via apoptosis in several tumor cell lines. In this study, we have examined the potential role of several genes, which were stably transfected into T-cell lines and which regulate apoptosis in different ways, on goniothalamin-induced cell death. Overexpression of full-length receptor for activated protein C-kinase 1 (RACK-1) and pc3n3, which up-regulates endogenous RACK-1, in both Jurkat and W7.2 T cells resulted in inhibition of goniothalamin-induced cell death as assessed by MTT and clonogenic assays. However, overexpression of rFau (antisense sequence to Finkel-Biskis-Reilly murine sarcoma virus-associated ubiquitously expressed gene) in W7.2 cells did not confer resistance to goniothalamin-induced cell death. Etoposide, a clinically used cytotoxic agent, was equipotent in causing cytotoxicity in all the stable transfectants. Assessment of DNA damage by Comet assay revealed goniothalamin-induced DNA strand breaks as early as 1 h in vector control but this effect was inhibited in RACK-1 and pc3n3 stably transfected W7.2 cells. This data demonstrate that RACK-1 plays a crucial role in regulating cell death signalling pathways induced by goniothalamin.

Cardiovascular disease risk management in HIV patients, experiences from Greater Manchester

Antiretroviral (ARV) therapy in HIV patients can cause hyperlipidaemia, glucose intolerance and insulin resistance, which increase the risk of cardiovascular disease (CVD). An audit carried out in Manchester found that CVD risk factors were common among HIV patients receiving ARVs; however, the management of risk factors was not satisfactory. Adopting a formal system to identify and manage CVD risk factors as well as appropriate referral for specialist management of complications of ARV therapy would improve patient care.

Is the enthesitis-related arthritis subtype of juvenile idiopathic arthritis a form of chronic reactive arthritis?

OBJECTIVE

Enteric organisms are known to trigger reactive arthritis. The enthesitis-related arthritis (ERA) form of juvenile idiopathic arthritis (JIA) clinically resembles reactive arthritis. Therefore, we looked for a role of enteric bacteria in ERA.

METHODS

Synovial fluid (SF) was obtained from 26 patients with ERA and 10 patients with rheumatoid arthritis (RA). Blood specimens were also obtained from patients with ERA and from 10 normal individuals. Lymphocyte proliferation assays were done on whole blood and SF mononuclear cells using as antigens crude lysates of the enteric bacteria Salmonella typhimurium, Yersinia enterocolitica, Shigella flexneri and Campylobacter jejuni. Crude lysate of Escherichia coli was used as a control antigen. HLA-B27 typing was done using the polymerase chain reaction. Homing of gut-specific T cells (CD103+) to the synovial compartment was studied using tri-colour flow cytometry. The antigen-specific cytokine profile was determined by flow cytometry.

RESULTS

Antigen-specific lymphoproliferative responses were observed in 14 of 26 patients. Among these patients, 12 showed a response in SF (four each to S. typhimurium and C. jejuni, and in two each to S. flexneri and Y. enterocolitica), and two patients in blood (S. typhimurium in both). None of the healthy controls showed a response in the blood. Lymphoproliferative responses in SF were more frequent in patients with JIA (12/26) than in controls with RA (1/10, P < 0.05). Patients with an antigen-specific response had a higher ratio of SF/blood CD103+ T cells compared with those with no antigen-specific response (P < 0.01). Antigen-specific as well as mitogen-stimulated cytokine production showed a Th1 bias.

CONCLUSION

Enteric bacteria may have a role in exacerbation of disease in patients with ERA. The immune response in patients with ERA is Th1-dominant.

Synthesis and antitubercular activities of bis-glycosylated diamino alcohols

Conjugate addition of diamines to glycosyl olefinic esters 1a and 1b followed by reduction of resulting bis-glycosyl beta-amino esters (2-7 and 14-19) with lithium aluminium hydride led to the respective glycosyl amino alcohols (8-13 and 20-25) in moderate to good yields. All the compounds were evaluated for antitubercular activity against Mycobacterium tuberculosis H(37)Ra and H(37)Rv. Few of the compounds exhibited antitubercular activity with MIC as low as 6.25-3.12microg/mL in virulent and avirulent strains. Compound 13 was found to be active against MDR strain and showed mild protection in mice.

Total intravenous anaesthesia for tracheobronchial stenting in children

Stenosis and malacia of the tracheobronchial tree, most often secondary to prolonged intubation, tracheostomy or following correction of a congenital cardiac lesion, present a significant therapeutic problem, especially when the lesions are extensive. The utilization of self-expanding tracheobronchial stents is a useful addition to the medical armamentarium for maintenance of airways in these patients with major airway stenosis and collapse. The majority of previous reported cases of tracheobronchial stenting have been performed under general anaesthesia with the help of rigid bronchoscopy under direct vision. We conducted two cases of tracheobronchial stenting in postoperative cardiosurgical babies under continuous propofol infusion taking advantage of cardiovascular stability during continuous infusion and rapid emergence after its discontinuation.

Perioperative management of long QT syndrome in a child with congenital heart disease

During cardiac catheterization, a 2(1/2)-year-old boy developed sudden cardiac arrest. The presence of a long QT interval in the electrocardiogram (ECG) along with ventricular arrhythmia and syncope at that moment enabled us to diagnose long QT syndrome (LQTS). Immediate defibrillation and beta-blocker (metoprolol) therapy saved the life of the child. Cardiac catheterization was completed and the child was planned for Fontan operation. Beta-blocker coverage, prevention of sympathetic stimulation and avoidance of agents which prolong the QT interval made anesthesia uneventful. There were episodes of ventricular fibrillation (VF) in the postoperative period. The child was managed with electrical defibrillation, metoprolol and magnesium.

Differential expression of WISP-1 and WISP-2 genes in normal and transformed human breast cell lines

The transcriptional alterations of specific gene(s) are actively associated with the development of different cancers including breast. The preceding studies of different laboratories documented at least 40 genes that may contribute directly to the genesis of cancer. Using differential display, RT-PCR and DNA sequencing analyses in normal human mammary epithelial cells (HMEC) and various breast tumor cell lines including MCF-7, ZR-75, T-47D and SKBR2, we demonstrated that WISP-1 and WISP-2 genes are differentially transcribed in these cells. WISP-2 mRNA transcription was identified in all 4 tumor derived cell lines, but the mRNA expression was undetected or minimally detected in normal breast epithelial cells. WISP-1 mRNA expression was identified in normal and transformed cell lines. However, the level of expression was higher in different breast tumor cell lines as compared to HMEC. The mRNA expression profiles of WISP genes in normal breast epithelial cells and breast tumor derived cell lines indicated a strong possibility of the involvement of WISP-signaling in the development of human breast tumors, and can be utilized as genetic markers of this disease.

Serous fluid leakage following modified Blalock-Taussig operation using PTFE grafts

BACKGROUND

Serous fluid leakage is an unusual but often devastating complication following the placement of a modified Blalock-Taussig shunt using a polytetrafluoroethylene graft.

METHOD AND RESULTS

Between September 1994 and September 1999, out of 268 patients undergoing a modified Blalock-Taussig shunt using polytetrafluoroethylene grafts, 10 developed massive pleural effusion or seroma due to a leak from the surface of the shunt. The age of the patients ranged from 9 days to 7 years. There were 7 males and 3 females. Nine patients presented with respiratory distress between 2 and 12 weeks of shunt surgery and one presented with sudden cardiac arrest. The shunt was patent in all the patients. Initial management was conservative. i.e. by pharmacological means and tube thoracostomy. Reoperation was undertaken in 9 patients when conservative treatment failed. All patients survived except one who had a cardiac arrest before any intervention could be carried out.

CONCLUSIONS

Patients with serous effusion have significant morbidity and mortality and often require reoperation. The initial management remains conservative but, if unsuccessful, re-exploration can be undertaken as it proved to be uniformly successful in our experience.