Genetic architecture of alcohol consumption identified by a genotype-stratified GWAS and impact on esophageal cancer risk in Japanese people

An East Asian-specific variant on aldehyde dehydrogenase 2 (ALDH2 rs671, G>A) is the major genetic determinant of alcohol consumption. We performed an rs671 genotype-stratified genome-wide association study meta-analysis of alcohol consumption in 175,672 Japanese individuals to explore gene-gene interactions with rs671 behind drinking behavior. The analysis identified three genome-wide significant loci (GCKR, KLB, and ADH1B) in wild-type homozygotes and six (GCKR, ADH1B, ALDH1B1, ALDH1A1, ALDH2, and GOT2) in heterozygotes, with five showing genome-wide significant interaction with rs671. Genetic correlation analyses revealed ancestry-specific genetic architecture in heterozygotes. Of the discovered loci, four (GCKR, ADH1B, ALDH1A1, and ALDH2) were suggested to interact with rs671 in the risk of esophageal cancer, a representative alcohol-related disease. Our results identify the genotype-specific genetic architecture of alcohol consumption and reveal its potential impact on alcohol-related disease risk.

Multiple intra-articular injections with adipose-derived stem cells for knee osteoarthritis cause severe arthritis with anti-histone H2B antibody production

Introduction

Osteoarthritis (OA) is the most common form of arthritis. OA results from the breakdown of cartilage, which leads to deterioration of the entire joint and the connective tissue that holds the joint together, and gradually and irreversibly worsens over time. Adipose-derived stem/stromal cells (ADSCs) have been used in the treatment of knee OA. However, the safety and efficacy of ADSC treatment of OA remain unclear. In this study, we investigated the pathophysiology of severe knee arthritis that occurred after ADSC treatment by screening for autoantibodies in synovial fluid from patients who received ADSC treatment.

Methods

Adult Japanese patients with OA who received ADSC treatment at Saitama Cooperative Hospital between June 2018 and October 2021 were enrolled. Antibodies (Abs) were screened using immunoprecipitation (IPP) with [³⁵S]-methionine-labeled HeLa cell extracts. The detected protein was identified by liquid chromatography coupled with time-of-flight mass spectrometry (MS) and ion trap MS, and the corresponding proteins were confirmed as autoantigens using immunoblotting. Ab titers were measured using an enzyme-linked immunosorbent assay.

Results

A total of 113 patients received ADSC treatment, and 75% (85/113) received ADSC injection at least twice with a 6-month interval between. No obvious abnormalities were observed in any patient after their first treatment; by contrast, 53% (45/85) of patients who received their second or third ADSC injection showed severe knee arthritis. IPP detected a common anti-15 kDa Ab in synovial fluid of 62% (8/13) of the samples analyzed from patients who showed severe arthritis. This Ab was not detected in synovial fluid obtained from the same joints before treatment. The corresponding autoantigen was identified as histone H2B. All available synovial samples from patients who tested positive for anti-histone H2B Ab were newly positive after the treatment; that is, none had been positive for anti-histone H2B Ab before treatment.

Conclusions

Multiple ADSC injections for OA induced severe arthritis in a high percentage of patients, particularly after the second injection. Synovial fluid from some patients with knee arthritis contained Ab to histone H2B that appeared only after ADSC treatment. These findings provide new insights into the pathogenesis of ADSC treatment-induced severe arthritis.

Long non-coding RNA TILR constitutively represses TP53 and apoptosis in lung cancer

Non-coding RNAs have an integral regulatory role in numerous functions related to lung cancer development. Here, we report identification of a novel lncRNA, termed TP53-inhibiting lncRNA (TILR), which was found to function as a constitutive negative regulator of p53 expression, including activation of downstream genes such as p21 and MDM2, and induction of apoptosis. A proteomic search for TILR-associated proteins revealed an association with PCBP2, while the mid-portion of TILR was found to be required for both PCBP2 and p53 mRNA binding. In addition, depletion of PCBP2 resulted in phenocopied effects of TILR silencing. TILR was also shown to suppress p53 expression in a post-transcriptional manner, as well as via a positive feedback loop involving p53 and Fanconi anemia pathway genes. Taken together, the present findings clearly demonstrate that TILR constitutively inhibits p53 expression in cooperation with PCBP2, thus maintaining p53 transcriptional activity at a level sufficiently low for avoidance of spurious apoptosis induction.

Assessment of anthracycline-induced cardiotoxicity in patients with childhood cancer survivor for long-term follow-up

Funding Acknowledgements

Type of funding sources: None.

Background

 Anthracycline cardiotoxicity is an important prognostic determinant in childhood cancer survivors (CCSs). That has been reported to improve with early therapeutic intervention, and because it is dose-dependent and progressive, early diagnosis and long-term follow-up are important. In adult survivors of cancer, the longitudinal strain (LS) is useful as a sensitive index of cardiac function. In childhood cancer survivors, strain abnormalities are also observed at both short-term and long-term follow-up. Global longitudinal strain (GLS) abnormalities are common during or early after chemotherapy, whereas changes in global circumferential strain (GCS) are more significant and consistent on long-term follow-up.

Purpose

 In this study, we aimed to conduct a cross-sectional study using strain analysis in childhood cancer survivors of a wide age range to clarify the mode of progression of anthracycline-induced cardiotoxicity and to identify useful indicators for long-term follow-up.

Methods

 In total, 116 patients (median age: 15.5 [range: 4.7-40.2] years) with childhood cancer who had passed at least 1 year after chemotherapy with anthracycline, and 116 control patients of similar age. Strain measurements were assessed for longitudinal strain (LS) and circumferential strain at the apical, papillary and basal levels using speckle tracking imaging. Estimated value at 5, 15, 25 and 35 years old were mathematically calculated.

Results

 Results were shown in tables and figures. Most of conventional echocardiographic parameters were not significantly different between CCCs and controls. LS, papillary CS and basal CS in CCCs decreased compared to normal controls at all age. The difference of estimated value between CCCs and normal controls in LS at all age were relatively constant. However, those in basal CS tended to increase with aging. Furthermore, basal CS in CCCs decreased with aging (r = 0.212, p < 0.001) and the duration after completion of anthracycline treatment (r = -0.244, p < 0.008).

Conclusions

 In childhood cancer survivors, strain analysis is a more sensitive indicators of cardiac function than conventional parameters. In addition, basal CS may decrease most markedly over time and could be useful indicator in long-term follow-up. Longitudinal studies should be conducted in the future to improve the accuracy of predicting anthracycline cardiotoxicity. These are new findings regarding the decline in cardiac function in childhood cancer survivors. Abstract Figure. Relationship between age and strains  Abstract Figure. Estimated values for each age group

Meclozine Attenuates the MARK Pathway in Mammalian Chondrocytes and Ameliorates FGF2-Induced Bone Hyperossification in Larval Zebrafish

Meclozine has been developed as an inhibitor of fibroblast growth factor receptor 3 (FGFR3) to treat achondroplasia (ACH). Extracellular signal regulated kinase (ERK) phosphorylation was attenuated by meclozine in FGF2-treated chondrocyte cell line, but the site of its action has not been elucidated. Although orally administered meclozine promoted longitudinal bone growth in a mouse model of ACH, its effect on craniofacial bone development during the early stage remains unknown. Herein, RNA-sequencing analysis was performed using murine chondrocytes from FGF2-treated cultured tibiae, which was significantly elongated by meclozine treatment. Gene set enrichment analysis demonstrated that FGF2 significantly increased the enrichment score of mitogen-activated protein kinase (MAPK) family signaling cascades in chondrocytes; however, meclozine reduced this enrichment. Next, we administered meclozine to FGF2-treated larval zebrafish from 8 h post-fertilization (hpf). We observed that FGF2 significantly increased the number of ossified vertebrae in larval zebrafish at 7 days post-fertilization (dpf), while meclozine delayed vertebral ossification in FGF2-induced zebrafish. Meclozine also reversed the FGF2-induced upregulation of ossified craniofacial bone area, including ceratohyal, hyomandibular, and quadrate. The current study provided additional evidence regarding the inhibitory effect of meclozine on the FGF2-induced upregulation of MAPK signaling in chondrocytes and FGF2-induced development of craniofacial and vertebral bones.

Abstract 1903: PTEN loss mediates clinical cross-resistance to CDK4/6 and PI3Ká inhibitors in breast cancer

The combination of CDK4/6 inhibitors with anti-estrogen therapies significantly improves clinical outcomes in ER-positive advanced breast cancer. To identify mechanisms of acquired resistance, we analyzed serial biopsies and rapid autopsies from patients treated with the combination of the CDK4/6 inhibitor ribociclib with letrozole. This study revealed that some resistant tumors acquired RB loss, whereas other tumors lost PTEN expression at the time of progression. In breast cancer cells ablation of PTEN, through increased AKT activation, was sufficient to promote resistance to CDK4/6 inhibition in vitro and in vivo. Mechanistically, PTEN loss resulted in exclusion of p27 from the nucleus, leading to increased activation of both CDK4 and CDK2. Since PTEN loss also causes resistance to PI3Kα-inhibitors, currently approved in the post-CDK4/6 setting, these findings provide critical insight into how this single genetic event may cause clinical cross-resistance to multiple targeted therapies in the same patient, with implications for optimal treatment sequencing strategies.

Citation Format: Carlotta Costa, Ye Wang, Amy Ly, Yasuyuki Hosono, Ellen Murchie, Charlotte S. Walmsley, Tiffany Huynh, Christopher Healy, Rachel Peterson, Shogo Yanase, Charles T. Jakubik, Laura E. Henderson, Leah J. Damon, Daria Timonina, Ioannis Sanidas, Christopher J. Pinto, Mari Mino-Kenudson, James Stone, Nicholas J. Dyson, Leif W. Ellisen, Aditya Bardia, Hiromichi Ebi, Cyril H. Benes, Jeffrey A. Engelman, Dejan Juric. PTEN loss mediates clinical cross-resistance to CDK4/6 and PI3Ká inhibitors in breast cancer [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1903.

Genome-wide association meta-analysis identifies GP2 gene risk variants for pancreatic cancer

Pancreatic cancer is the fourth leading cause of cancer-related deaths in Japan. To identify risk loci, we perform a meta-analysis of three genome-wide association studies comprising 2,039 pancreatic cancer patients and 32,592 controls in the Japanese population. Here, we identify 3 (13q12.2, 13q22.1, and 16p12.3) genome-wide significant loci (P < 5.0 × 10⁻⁸), of which 16p12.3 has not been reported in the Western population. The lead single nucleotide polymorphism (SNP) at 16p12.3 is rs78193826 (odds ratio = 1.46, 95% confidence interval = 1.29-1.66, P = 4.28 × 10⁻⁹), an Asian-specific, nonsynonymous glycoprotein 2 (GP2) gene variant. Associations between selected GP2 gene variants and pancreatic cancer are replicated in 10,822 additional cases and controls of East Asian origin. Functional analyses using cell lines provide supporting evidence of the effect of rs78193826 on KRAS activity. These findings suggest that GP2 gene variants are probably associated with pancreatic cancer susceptibility in populations of East Asian ancestry.

Previous genome-wide association studies have identified risk loci for pancreatic cancer but were centered on individuals of European ancestry. Here the authors identify GP2 gene variants associated with pancreatic cancer susceptibility in populations of East Asian ancestry.

P1357 Left atrial function decreases with age in patients with repaired tetralogy of Fallot decrease

BACKGROUND

Left ventricular function has been shown to be an important prognostic indicator in patients with repaired tetralogy of Fallot (rTOF) and tends to decrease with age. In recent years, left atrial (LA) function was reported to be a useful prognostic indicator more than or equal to left ventricular function in acquired heart diseases. However, atrial function in rTOF has not yet been sufficiently examined.

PURPOSE

The aim of this study was to investigate the relationship between LA dysfunction and age in rTOF using strain analysis.

METHODS

In order to assess the relationship between LA function and age, we recruited 59 patients with rTOF ranging in age from 5-40 years. We stratified the patients into 3 groups (T1: 5-10 years, T2: 11-20 years, T3: 21-40 years) and divided 54 controls of similar age into 3 corresponding groups (N1, N2, and N3). Two-dimensional speckle tracking images (2D-STI) obtained from four- and two-chamber views were used to assess LA functions by measuring reservoir, conduit, and pump strain. Additionally, we measured the strain rate (SR) in the systole, early diastole, and late diastole.

RESULTS

LA reservoir strain (37.4 ± 2.2% vs. 47.9 ± 1.7%, P= 0.004), LA pump strain (8.3 ± 1.4% vs. 14.1 ± 2.7%, p &lt;.001), atrial systolic LA-SR (1.5 ± 0.4% vs. 2.4 ± 0.6%, p &lt;.001), and systolic LA-SR (1.5 ± 0.3% vs. 2.1 ± 0.4%, p = 0.003) were significantly decreased in T3 compared with N3. Although only LA conduit strain decreased with aging (r = -0.3204, p = 0011) in controls, all of the LA reservoir (r = -0.325, p = 0.020), conduit (r = -0.314, p = 0.025), and pump strain (r = -0.481, p &lt; 0.001) in rTOF decreased with aging.

Early diastole SR was significantly decreased in the T1 and T3 groups compared with the N1 and N3 groups (T1 vs N1, 3.00 ± 0.63% vs. 4.03 ± 0.0.80%, p &lt;.0.001, T3 vs N3, 2.31 ± 0.57% vs.3.31 ± 0.47%, p &lt; 0.001). Both systolic SR and late diastole SR decreased in T3 group compared with the N3 (1.54 ± 0.32% vs. 2.08 ± 0.42%, p = 0.003, 1.42 ± 0.32% vs.2.42 ± 0.61%, p &lt; 0.001), respectively. Although only early diastole SR decreased with aging (r = -0.415, p &lt; 0.001) in controls, all of the systole (r = -0.287, p = 0.041), early diastole (r = -0.337, p = 0.019), and late diastole SR (r = -0.407, p = 0.003) in rTOF decreased with aging.

CONCLUSIONS

In rTOF, most of the LA functions assessed by strain analysis decreased compared to normal controls in over 20 years old age. Furthermore, all measured functions decreased with age in rTOF while only two parameters decreased with age in normal controls. These results suggest that LA function may be an important indicator in long-term rTOF follow-up. These are new insights into LA function in patients with rTOF.

P1358 New insights into cardiac dysfunction assessed by left atrial function in patients with type 1 diabetes mellitus

BACKGROUND

There have been many reports of heart failure due to diabetic cardiomyopathy and decreased left ventricular (LV) function with increasing age in patients with type 1 diabetes mellitus (T1DM). Recently, although left atrial (LA) function has been occasionally reported to be a more useful prognostic indicator than LV function in acquired heart diseases, LA function in patients with T1DM has not yet been studied.

PURPOSE

To investigate LA dysfunction in patients with T1DM.

METHODS

Fifty patients with T1DM were recruited (age, 5–41 years). We excluded patients who had a history of heart disease, hypertension, and those taking cardioprotective agents. The patients and 50 age-matched controls were classified into 3 age groups (D1, C1, 5–14 years; D2, C2, 15–29 years; D3, C3, 30–41 years). The LA phasic function serving as the reservoir, conduit, and pump strains; the LA strain rate (SR) in the systole, early diastole, and late diastole; and the LV global longitudinal strain (LV-LS) as determined via 2-dimensional speckle tracking imaging were measured from the apical four- and two-chamber views. We also calculated the LA stiffness index as the ratio of E/e’ to the LA reservoir strain.

RESULTS

There was no significant difference in left ventricular ejection fraction in each age group. The LA reservoir strains in D2 and D3 were significantly lower than those in C2 (40.8 ± 5.7% vs. 47.2 ± 5.5%, p = 0.005) and C3 (39.2 ± 5.5% vs. 47.3 ± 5.7%, p = 0.004), respectively. The LA conduit strain in D2 was significantly lower than that in C2 (28.9 ± 5.8% vs. 35.0 ± 5.0%, p = 0.006). The LA pump strain and the three phases of LA SR were not significantly different among the age groups. The LA stiffness index in D3 increased significantly compared to that in N3 (0.18 ± 0.05 vs. 0.13 ± 0.01, p &lt;0.001). The LV-LS in D2 and D3 was significantly lower than that in C2 (-15.7 ± 1.7% vs. -18.7 ± 2.1%, p &lt;0.001) and C3 (-15.3 ± 1.8% vs. -19.3 ± 2.0%, p &lt;0.001), respectively. The LA reservoir strain significantly correlated with LV-LS (r = -0.468, p &lt; 0.001). Both the LA reservoir strain and LV-LS in patients with T1DM decreased significantly (p = 0.028, p &lt; 0.042, respectively) and correlated with increasing age (r = -0.323, r = 0.286, respectively). The LV stiffness index did not correlate with age or LV-LS.

CONCLUSIONS

The LA reservoir strain might be as useful as LV-LS as an early marker of cardiac dysfunction in patients with T1DM. The correlation coefficient between the LA reservoir strain and LV-LS was not strong. Therefore, although LV-LS might affect the LA reservoir strain, it might represent other aspects of cardiac dysfunction. The increase of LA stiffness might represent the changes in LA wall properties and could be another useful indicator of cardiac dysfunction during long-term follow-ups, which is independent of LV-LS. Overall, these findings provide new insights into cardiac dysfunction in patients with T1DM.

PTEN Loss Mediates Clinical Cross-Resistance to CDK4/6 and PI3Kα Inhibitors in Breast Cancer

The combination of CDK4/6 inhibitors with antiestrogen therapies significantly improves clinical outcomes in ER-positive advanced breast cancer. To identify mechanisms of acquired resistance, we analyzed serial biopsies and rapid autopsies from patients treated with the combination of the CDK4/6 inhibitor ribociclib with letrozole. This study revealed that some resistant tumors acquired RB loss, whereas other tumors lost PTEN expression at the time of progression. In breast cancer cells, ablation of PTEN, through increased AKT activation, was sufficient to promote resistance to CDK4/6 inhibition in vitro and in vivo. Mechanistically, PTEN loss resulted in exclusion of p27 from the nucleus, leading to increased activation of both CDK4 and CDK2. Because PTEN loss also causes resistance to PI3Kα inhibitors, currently approved in the post-CDK4/6 setting, these findings provide critical insight into how this single genetic event may cause clinical cross-resistance to multiple targeted therapies in the same patient, with implications for optimal treatment-sequencing strategies. SIGNIFICANCE: Our analysis of serial biopsies uncovered RB and PTEN loss as mechanisms of acquired resistance to CDK4/6 inhibitors, utilized as first-line treatment for ER-positive advanced breast cancer. Importantly, these findings have near-term clinical relevance because PTEN loss also limits the efficacy of PI3Kα inhibitors currently approved in the post-CDK4/6 setting.This article is highlighted in the In This Issue feature, p. 1.

Abstract 4503: Functional CRISPR screen towards identifying novel conserved long noncoding RNAs with oncogenic activity

Large-scale transcriptome analysis has enabled the systematic profiling of long non-coding RNAs (lncRNAs) in cancer- or lineage-specific contexts. Although a significantly larger portion of the genome is transcribed into lncRNAs compared to proteins, only a small set of them appears to be evolutionally conserved across organisms. In general, functionally essential genes are subject to stronger selective pressure, and are thus more evolutionarily conserved than nonessential genes. However, it remains a question whether the evolutionally conserved lncRNAs play essential roles for cell growth and development. Recently, our lab described THOR, the first evolutionarily conserved lncRNA that is testis/cancer-specific and accelerates tumor growth in preclinical models. Based on these discoveries, we hypothesized that a subclass of conserved lncRNAs that are functionally essential for tumor growth and cancer progression should exist. To test this hypothesis, we first developed a top-down approach to generate a list of cancer-associated evolutionary conserved lncRNAs. By integrating base-pair conservation, best 200-bp conservation, and transcript expression information, we identified a total of 85 ultra-conserved lncRNAs that are expressed in cancer. We then set up a CRISPR-Cas9 based system to screen for functionally essential lncRNAs in various lineages of cancer. Unlike protein-coding genes, whose expression can be efficiently disrupted by conventional single guide RNA-based CRISPR-Cas9 system, lncRNA transcripts are insensitive to read-frame alterations. We thus utilized an lncRNA deletion strategy featured by paired guide RNAs flanking the conserved domains within the lncRNA transcript. We designed a total of 858 pairs of guide RNAs (gRNAs) targeting 242 conserved domains within the 85 ultra-conserved lncRNAs and protein-coding gene controls. Sequencing validation of the library confirms more than 90% coverage of the designed gRNA pairs. Using this library, we have performed functional CRISPR screens in cancer cell line models from various lineages, namely, MIA-PaCa-2 (pancreatic ductal adenocarcinoma), SK-N-Mc (neuroepithelioma), and VCaP (prostate cancer). Notably, we have successfully discovered both novel and previously reported oncogenic lncRNAs (e.g. ZNF503-AS1), which, upon knockout, significantly delayed cell growth (represented by the diminished count of guide RNAs targeting these genes in the cell population). Therefore, from these CRISPR screens, we discovered ultra-conserved lncRNAs with suggestive oncogenic roles in a lineage-specific or pan-cancer manner. Further interrogation of their structures, cellular locations, and interactomes is warranted to reveal their contributions to cancer progression.

Citation Format: Yajia Zhang, Lanbo Xiao, Mengyao Tan, Yasuyuki Hosono, Arul Chinnaiyan. Functional CRISPR screen towards identifying novel conserved long noncoding RNAs with oncogenic activity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4503.

Increased Synthesis of MCL-1 Protein Underlies Initial Survival of EGFR-Mutant Lung Cancer to EGFR Inhibitors and Provides a Novel Drug Target

Purpose: EGFR inhibitors (EGFRi) are effective against EGFR-mutant lung cancers. The efficacy of these drugs, however, is mitigated by the outgrowth of resistant cells, most often driven by a secondary acquired mutation in EGFR, T790M We recently demonstrated that T790M can arise de novo during treatment; it follows that one potential therapeutic strategy to thwart resistance would be identifying and eliminating these cells [referred to as drug-tolerant cells (DTC)] prior to acquiring secondary mutations like T790M Experimental Design: We have developed DTCs to EGFRi in EGFR-mutant lung cancer cell lines. Subsequent analyses of DTCs included RNA-seq, high-content microscopy, and protein translational assays. Based on these results, we tested the ability of MCL-1 BH3 mimetics to combine with EGFR inhibitors to eliminate DTCs and shrink EGFR-mutant lung cancer tumors in vivo Results: We demonstrate surviving EGFR-mutant lung cancer cells upregulate the antiapoptotic protein MCL-1 in response to short-term EGFRi treatment. Mechanistically, DTCs undergo a protein biosynthesis enrichment resulting in increased mTORC1-mediated mRNA translation of MCL-1, revealing a novel mechanism in which lung cancer cells adapt to short-term pressures of apoptosis-inducing kinase inhibitors. Moreover, MCL-1 is a key molecule governing the emergence of early EGFR-mutant DTCs to EGFRi, and we demonstrate it can be effectively cotargeted with clinically emerging MCL-1 inhibitors both in vitro and in vivo Conclusions: Altogether, these data reveal that this novel therapeutic combination may delay the acquisition of secondary mutations, therefore prolonging therapy efficacy. Clin Cancer Res; 24(22); 5658-72. ©2018 AACR.

Abstract 4982: Oncogenic role of THOR, a conserved cancer/testis long noncoding RNA

Large scale transcriptome sequencing efforts have vastly expanded the catalog of long non-coding RNAs (lncRNAs) with varying evolutionary conservation, lineage expression, and cancer specificity. Through a recent large-scale transcriptomic analysis over 6,500 tumor RNA-seq samples, we discovered over 50,000 lncRNAs in the human genome, many of which exhibited highly evolutionarily conserved sequence patterns. Building upon the discovery of these highly conserved lncRNAs, we functionally characterized a novel ultraconserved lncRNA, THOR, which exhibits expression exclusively in testis and a broad range of human cancers. We establish THOR as the first discovered cancer/testis lncRNA, and further investigated its functional significance. THOR knockdown and overexpression in multiple cell lines and animal models alters cell or tumor growth supporting an oncogenic role. Namely, we generated CRISPR knockout cell line models, showing a definitive role for THOR in cancer progression. Additionally, given the sequence conservation of THOR through the mouse and zebrafish, we generated a zebrafish knockout model, and also a zebrafish overexpression model for THOR. Through RNA-pulldown followed by mass spectrometry, we discovered a conserved interaction of THOR with the RNA binding protein, IGF2BP1, in both human and zebrafish cells. We further show that THOR contributes to the mRNA stabilization activities of IGF2BP1. These findings are corroborated by iCLIP data for IGF2BP1. Notably, transgenic THOR knockout produced fertilization defects in zebrafish and also conferred a resistance to melanoma onset in an NRAS K61-induced zebrafish melanoma model. Likewise, ectopic expression of human THOR in zebrafish accelerated the onset of melanoma. THOR represents a novel class of functionally important cancer/testis lncRNAs whose structure and function have undergone positive evolutionary selection.

Citation Format: Yashar Niknafs, Yasuyuki Hosono, Matthew K, John Prensner, Rohit Mehra, Sethuramasundaram Pitchiaya, Jean Tien, Rohit Malik, Weibin Zhao, Arul Chinnaiyan. Oncogenic role of THOR, a conserved cancer/testis long noncoding RNA [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4982.

Abstract 2458: The androgen receptor-regulated lncRNA landscape reveals a role for ARlnc1 in prostate cancer progression

The androgen receptor (AR) signaling plays a key role in the development of the normal prostate as well as prostate cancer. While substantial efforts have been undertaken to study AR-regulated protein-coding genes in primary prostate cancer and castration-resistant prostate cancer, few studies have investigated the role of long noncoding RNAs. In this study, we employed transcriptome sequencing to delineate long noncoding RNAs (lncRNAs) associated with AR signaling in prostate cancer progression. ARlnc1 (AR-regulated lncRNA 1) was identified as being the top AR-induced, cancer-associated lncRNA in an integrative analysis of prostate cancer cell lines and tissues. Not only was ARlnc1 induced by AR, but ARlnc1 also was shown to sustain AR signaling by stabilizing the AR transcript via interaction with the AR 3' UTR. Knockdown of ARlnc1 suppressed AR expression, global AR signaling, and prostate cancer growth in vitro and in vivo. Taken together, these data support a role for ARlnc1 in maintaining a positive feedback loop that potentiates AR signaling during prostate cancer progression, and identifies ARlnc1 as a novel therapeutic target.

Citation Format: Yajia Zhang, Sethuramasundaram Pitchiaya, Marcin Cieślik, Yashar S. Niknafs, Jean C. Tien, Yasuyuki Hosono, Lisha Wang, Yuanyuan Qiao, Xuhong Cao, Mats Ljungman, Hui Jiang, Rohit Mehra, Shuling Guo, Rohit Malik, Arul M. Chinnaiyan. The androgen receptor-regulated lncRNA landscape reveals a role for ARlnc1 in prostate cancer progression [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2458.

Analysis of the androgen receptor-regulated lncRNA landscape identifies a role for ARLNC1 in prostate cancer progression

The androgen receptor (AR) plays a critical role in the development of the normal prostate as well as prostate cancer. Using an integrative transcriptomic analysis of prostate cancer cell lines and tissues, we identified ARLNC1 (AR-regulated long non-coding RNA 1) as an important long non-coding RNA that is strongly associated with AR signaling in prostate cancer progression. Not only was ARLNC1 induced by AR protein, ARLNC1 stabilized the AR transcript via RNA-RNA interaction. ARLNC1 knockdown suppressed AR expression, global AR signaling, and prostate cancer growth in vitro and in vivo. Taken together, these data support a role for ARLNC1 in maintaining a positive feedback loop that potentiates AR signaling during prostate cancer progression, and identifies ARLNC1 as a novel therapeutic target.

Oncogenic Role of THOR, a Conserved Cancer/Testis Long Non-coding RNA

Large-scale transcriptome sequencing efforts have vastly expanded the catalog of long non-coding RNAs (lncRNAs) with varying evolutionary conservation, lineage expression, and cancer specificity. Here, we functionally characterize a novel ultraconserved lncRNA, THOR (ENSG00000226856), which exhibits expression exclusively in testis and a broad range of human cancers. THOR knockdown and overexpression in multiple cell lines and animal models alters cell or tumor growth supporting an oncogenic role. We discovered a conserved interaction of THOR with IGF2BP1 and show that THOR contributes to the mRNA stabilization activities of IGF2BP1. Notably, transgenic THOR knockout produced fertilization defects in zebrafish and also conferred a resistance to melanoma onset. Likewise, ectopic expression of human THOR in zebrafish accelerated the onset of melanoma. THOR represents a novel class of functionally important cancer/testis lncRNAs whose structure and function have undergone positive evolutionary selection.

Inactivating mutations and hypermethylation of the NKX2-1/TTF-1 gene in non-terminal respiratory unit-type lung adenocarcinomas

The major driver mutations of lung cancer, EGFR mutations and EML4-ALK fusion, are mainly detected in terminal respiratory unit (TRU)-type lung adenocarcinomas, which typically show lepidic and/or papillary patterns, but are rarely associated with a solid or invasive mucinous morphology. In order to elucidate the key genetic events in non-TRU-type lung cancer, we carried out whole-exome sequencing on 43 non-TRU-type lung adenocarcinomas based on morphology (17 acinar, nine solid, and two enteric adenocarcinomas, and 15 adenocarcinomas with a mucinous morphology). Our analysis identified mutations in TP53 (16/43, 37.2%), KRAS (13/43, 30.2%), and NKX2-1/TTF-1 (7/43; 16.3%) as the top three significantly mutated genes, while the EGFR mutation was rare (1/43, 2.3%) in this cohort. Eight NKX2-1/TTF-1 mutations (five frameshift, two nonsense, and one missense) were identified, with one case harboring two distinct NKX2-1/TTF-1 mutations (one missense and one frameshift). Functional assays with the NK2 homeobox 1 (NKX2-1)/thyroid transcription factor 1 (TTF-1) mutants revealed that none of them retain the activity as a transcriptional factor. Histologically, invasive mucinous adenocarcinomas accounted for most of the NKX2-1/TTF-1 mutations (five cases), as well as one enteric and one acinar adenocarcinoma. Immunohistochemistry showed that the cohort was largely divided into TTF-1-postive/hepatocyte nuclear factor 4-α (HNF4-α)-negative and TTF-1-negative/HNF4-α-positive groups. NKX2-1/TTF-1 mutations were exclusively found in the latter, in which the gastrointestinal markers, mucin 5AC and cytokeratin 20, were frequently expressed. Bisulfite sequencing revealed that the NKX2-1/TTF-1 gene body was highly methylated in NKX2-1/TTF-1-negative cases, including those without the NKX2-1/TTF-1 mutations. The genetic or epigenetic inactivation of NKX2-1/TTF-1 may play an essential role in the development and aberrant differentiation of non-TRU-type lung adenocarcinomas.

Abstract LB-008: KRAS engages AGO2 to enhance cellular transformation

Oncogenic mutations in RAS provide a compelling yet intractable therapeutic target. Approximately 30% of all cancers harbor activating mutations in the RAS family of small GTPase proteins, making it one of the most common oncogenic aberrations in humans. Normal RAS proteins (H, K or N-RAS) localize to the inner cell membrane and transduce extracellular growth signals by cycling between an “active” GTP-bound state and “inactive” GDP-bound state. Our understanding of RAS biology is primarily from RAS protein-effector interactions that activate a variety of effectors at the plasma membrane like RAF/PI3K/RalGDS. Yet, targeting mutant RAS proteins or its effectors / pathways remains a challenging endeavor for treating RAS driven cancers.

For a comprehensive identification of RAS interactors, we recently performed co-immunoprecipitation (Co-IP) Mass Spectrometric analysis of RAS immunoprecipitates from multiple cancer cell lines with differing KRAS mutation status. In all the cell lines studies, we uncovered an interaction between RAS and the core component of the RNA silencing machinery, Argonaute 2 (AGO2). Endogenously expressed RAS and AGO2 co-sediment and co-localize in intracellular membrane bound endoplasmic reticulum. AGO2 binds the Switch II region in KRAS, irrespective of GDP/GTP bound to RAS. Both endogenous and overexpressed mutant forms of KRAS, attenuate AGO2 related gene silencing function. Using NIH3T3 AGO2-/- cells, we demonstrate that the RAS-AGO2 interaction is required for maximal mutant KRAS expression and cellular transformation. Overall, our studies suggest that through its interaction with AGO2, RAS function extends well beyond its canonical role in intracellular signaling. We will present detailed characterization of the RAS-AGO2 interaction and its functional aspects that we have discovered so far.

Citation Format: Sunita Shankar, Sethuramasundaram Pitchiaya, Rohit Malik, Vishal Kothari, Yasuyuki Hosono, Anastasia K. Yocum, Harika Gundlapalli, Yasmine White, Ari Firestone, Xuhong Cao, Saravana M. Dhanasekaran, Jeanne Stuckey, Gideon Bollag, Kevin Shannon, Nils Walter, Chandan Kumar-Sinha, Arul M. Chinnaiyan. KRAS engages AGO2 to enhance cellular transformation. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr LB-008.

Abstract 983: Integrative analysis of androgen receptor regulated long non-coding RNA in prostate cancer

Androgen receptor (AR) plays a critical role in the development and progression of prostate cancer. AR regulates a large repertoire of genes; however, the effect of androgen signaling on the regulation of long non-coding RNAs (lncRNA) remains incompletely understood. Using transcriptome sequencing (RNA-seq) of AR-positive cell lines VCaP and LNCaP treated with dihydroxytestosterone (DHT), we identified genes, including lncRNAs, which were strongly regulated by AR. To confirm direct regulation by AR, we interrogated AR-ChIP-seq data from VCaP and LNCaP cells, identifying the lncRNAs with direct AR binding. Existence of these lncRNAs in prostate cancer tissue samples was confirmed by analysis of RNA-seq data from prostate tumors, and the degree of differential expression in prostate tumors (localized and castration resistant metastases) versus benign was determined. The most highly overexpressed lncRNA in this analysis was a 2.7kb multi-exonic transcript present on chromosome 16 called ARlnc1. RACE was utilized to determine the exact exon structure of this gene, and its expression levels in various prostate cancer cell lines as well as independent prostate cancer tissue cohorts was assessed. Further, knockdown of ARlnc1 in AR dependent cell lines inhibited cell proliferation and induced apoptosis. Knockdown of ARlnc1 affected molecular signatures related to cell cycle, mitosis and DNA damage. Interestingly, ARlnc1 knockdown also suppressed global androgen signaling as determined by Gene set enrichment analysis using AR gene signature. Upon investigation of the mechanism through which PRCAT47 regulate AR signaling, we discovered that ARlnc1 regulates AR at the level of translation. Taken together, our data suggests that many lncRNAs are regulated by androgen signaling, and we identify one such lncRNA that is involved in a protein-lncRNA positive feedback loop.

Citation Format: Rohit Malik, Yajia Zhang, Marcin Cieslik, Yashar S. Niknafs, Sethuramasundaram Pitchiaya, Yasuyuki Hosono, Shruthi Subramaniam, Sahr Yazdani, Xuhong Cao, Dan Robinson, Arul Chinnaiyan. Integrative analysis of androgen receptor regulated long non-coding RNA in prostate cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 983.

Clinical significance and new detection system of autoantibodies in myositis with interstitial lung disease

Anti-aminoacyl-tRNA synthetase (ARS) and anti-melanoma differentiation-associated gene 5 ( MDA5) antibodies are closely associated with interstitial lung disease in polymyositis and dermatomyositis. Anti-ARS-positive patients develop common clinical characteristics termed anti-synthetase syndrome and share a common clinical course, in which they respond well to initial treatment with glucocorticoids but in which disease tends to recur when glucocorticoids are tapered. Anti- MDA5 antibody is associated with rapidly progressive interstitial lung disease and poor prognosis, particularly in Asia. Therefore, intensive immunosuppressive therapy is required for anti- MDA5-positive patients from the early phase of the disease. New enzyme-linked immunosorbent assays to detect anti-ARS and anti- MDA5 antibodies have recently been established and are suggested to be efficient and useful. These assays are expected to be widely applied in daily practice.

Abstract PR10: HiClinc-1, a highly conserved Cancer-Testis lncRNA, regulates cell proliferation and tumor onset

Long non-coding RNA (lncRNAs) have been shown to play an important role is a variety of cellular processes including cancer initiation and progression. Recently, we described a landscape of lncRNA using RNA-Seq data from more than 5000 cancer samples from 18 tissue types. Using novel bioinformatics based approach we were able to discover almost 50,000 novel transcripts. This list includes a subset of lncRNAs that contain ultra-conserved elements (UCE) termed “Highly Conserved Long Intergenic Non-Coding RNAs (HICLINCs)”. This provides a new opportunity for exploring the functions of highly conserved lncRNAs using genomic approaches.

Among them, we focus on an lncRNA which we have termed HiClinc-1 (Highly Conserved Intergenic long-noncoding RNA-1), that is specifically expressed only in testis in benign tissue, and re-expressed in a broad range of cancer types. We described that HiClinc-1 exists in the messenger Ribonucleoprotein (mRNP) complex and binds to Insulin-Like Growth Factor 2 mRNA Binding Protein 1 (IGF2BP1), one of the component of mRNP complex in both human and zebrafish. HiClinc-1 regulates cell proliferation both in vivo and in vitro through the regulation of IGF2BP1's downstream target Insulin-Like Growth Factor 2 (IGF2). HiClinc-1 also enhanced tumor growth in mouse xenograft model. Notably, Human-HiClinc-1 injection in zebrafish embryos accelerated the onset and growth of NRAS K61-induced melanoma. Similarly, HiClinc-1 knockout background showed delayed onset of NRAS K61-induced melanoma. Taken together, we identified a novel Cancer-Testis lncRNA, which is highly conserved through human to zebrafish that can be a potential therapeutic target for cancer treatment.

Citation Format: Yasuyuki Hosono, John Prensner, Matthew Iyer, Yashar Niknafs, Rohit Malik, Anton Poliakov, Xuhong Cao, Jordan Shavit, Rohit Mehra, Weibin Zhou, Arul M. Chinnaiyan. HiClinc-1, a highly conserved Cancer-Testis lncRNA, regulates cell proliferation and tumor onset. [abstract]. In: Proceedings of the AACR Special Conference on Noncoding RNAs and Cancer: Mechanisms to Medicines ; 2015 Dec 4-7; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2016;76(6 Suppl):Abstract nr PR10.

Abstract LB-058: Novel interactions of the RAS oncoprotein

Approximately 30% of all cancers harbor activating mutations in the RAS family of small GTPase proteins, making it one of the most common oncogenic aberrations in humans. Normal RAS proteins (H, K or N-RAS) localize to the inner cell membrane and transduce extracellular growth signals by cycling between an “active” GTP-bound state and “inactive” GDP-bound state, through interactions with various “GTPase activating proteins” (GAPs) that promote RAS mediated GTP hydrolysis. Oncogenic mutants of RAS lose their catalytic activity or association with the GAP proteins, resulting in constitutively active GTP-bound state that signals through direct interactions with effector kinases like RAF and PI3K and activate the MEK/ERK and/or Akt, leading to activation of hallmark cancer pathways including growth factor independence, uncontrolled cell proliferation, evasion of apoptosis and immune responses, increased metabolism as well as metastases. Although RAS is the most frequently mutated gene driving multifarious pathways of oncogenesis, our knowledge of protein interactions involving RAS proteins have been largely limited to RAS binding domains in RAF/PI3K/RalGDS. Targeting mutant RAS proteins or its direct effectors, or pathways activated by RAS effectors remains a challenging endeavor for treating RAS driven cancers.

Towards the goal of a thorough understanding of RAS biology through a comprehensive identification of its interactors, we performed IP-Mass Spectrometric analysis of pan-RAS immunoprecipitates from multiple cell lines. Interestingly in our experiments, apart from the well-known interactor RAF, we found evidence of several novel RAS interacting proteins, including many with DNA and RNA binding motifs. Our study validates these findings through cell-free protein interaction analyses and explores the possible biological effects of these novel RAS interactions in mutant KRAS driven cellular transformation.

Note: This abstract was not presented at the meeting.

Citation Format: Sunita Shankar, Rohit Malik, Vishal Kothari, Yasuyuki Hosono, Sethuramasundaram Pitchiaya, Shanker Kalyana-Sundaram, Anastasia Yocum, June Escara-Wilke, Harika Gundlapalli, Krishnapriya Chinnaswamy, Matthew Shuler, Anton Poliakov, Xiaoju Wang, Vishalakshi Krishnan, Yasmine White, Ari Firestone, Xuhong Cao, Saravana M. Dhanasekaran, Jeanne Stuckey, Gideon Bollag, Kevin Shannon, Nils G. Walter, Chandan Kumar-Sinha, Arul Chinnaiyan. Novel interactions of the RAS oncoprotein. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr LB-058. doi:10.1158/1538-7445.AM2015-LB-058

NKX2-1/TTF-1: an enigmatic oncogene that functions as a double-edged sword for cancer cell survival and progression

Emerging evidence indicates that NKX2-1, a homeobox-containing transcription factor also known as TTF-1, plays a role as a "lineage-survival" oncogene in lung adenocarcinomas. In T cell acute lymphoblastic leukemia, gene rearrangements lead to aberrant expression of NKX2-1/TTF-1. Despite accumulating evidence supporting its oncogenic role, it has become apparent that NKX2-1/TTF-1 expression also has biological and clinical functions in the opposite direction that act against tumor progression. Herein, we review recent findings showing these enigmatic double-edged characteristics, with special attention given to the roles of NKX2-1/TTF-1 in lung development and carcinogenesis.

Abstract PR1: NKX2-1/TITF1/TTF-1-induced ROR1 is required to sustain EGFR survival signaling in lung adenocarcinoma

Emerging evidence, though currently sparse, suggests that “lineage-specific transcription factors” with developmental roles in normal progenitor cells of particular lineages may also confer dependency for survival to certain types of cancer cells. Accumulated evidence indicates that NKX2-1, a lineage-specific transcription factor also known as TITF1 and TTF-1, which is expressed in a major fraction of lung adenocarcinomas, plays essential roles in peripheral lung development. We previously identified NKX2-1 as a lineage-survival oncogene in lung adenocarcinoma, while other investigators reached similar conclusions through genome-wide searches for focal genomic aberrations. Previous findings including ours thus clearly indicate the requirement of sustained NKX2-1 expression for lung adenocarcinoma survival, while it remains elusive how NKX2-1 mediates survival signals.

In the present study, we show that NKX2-1 induces the expression of the receptor tyrosine kinase-like orphan receptor 1 (ROR1), which in turn sustains a favorable balance between prosurvival PI3K-AKT and proapoptotic p38 signaling, in part through ROR1 kinase-dependent c-Src activation. Interestingly, ROR1 was also identified as a receptor tyrosine kinase with a “sustainer role” for the interaction of EGFR-ERBB3 and ERBB3 phosphorylation in a ROR1 kinase-independent manner, consequentially leading to PI3K activation. It was also of note that ROR1 knockdown effectively inhibited lung adenocarcinoma cell lines irrespective of their EGFR status, including those with resistance to the EGFR tyrosine kinase inhibitor gefitinib. Secondary EGFR mutation, MET amplification, and HGF overexpression may arise in lung adenocarcinomas in patients undergoing EGFR-TKI treatment, leading to treatment resistance. The existence of such diverse mechanisms makes it difficult to predict which should be targeted to prevent expansion of resistant clones. From a clinical point of view, it is thus of particular interest that ROR1 inhibition appears to be effective for treatment of gefitinib-resistant lung adenocarcinomas with various resistance mechanisms.

Taken together, the present findings identify ROR1 as an “Achilles' heel” in lung adenocarcinomas. Future development of novel therapeutic means including ROR1-specific antibodies and small molecules that inhibit both or either of the two distinct prosurvival signal-sustaining functions is greatly anticipated for attempts to reduce the intolerable death toll from currently “hard-to-cure” lung adenocarcinomas.

This proffered talk is also presented as Poster A28.

Abstract LB-17: NKX2-1/TITF1/TTF-1-induced ROR1 is required to sustain EGFR survival signaling in lung adenocarcinoma

Emerging evidence, though currently sparse, suggests that “lineage-specific transcription factors” with developmental roles in normal progenitor cells of particular lineages may also confer dependency for survival to certain types of cancer cells. Accumulated evidence indicates that NKX2-1, a lineage-specific transcription factor also known as TITF1 and TTF-1, which is expressed in a major fraction of lung adenocarcinomas, plays essential roles in peripheral lung development. We previously identified NKX2-1 as a lineage-survival oncogene in lung adenocarcinoma, while other investigators reached similar conclusions through genome-wide searches for focal genomic aberrations. Previous findings including ours thus clearly indicate the requirement of sustained NKX2-1 expression for lung adenocarcinoma survival, while it remains elusive how NKX2-1 mediates survival signals. In the present study, we show that NKX2-1 induces the expression of the receptor tyrosine kinase-like orphan receptor 1 (ROR1), which in turn sustains a favorable balance between prosurvival PI3K-AKT and proapoptotic p38 signaling, in part through ROR1 kinase-dependent c-Src activation. Interestingly, ROR1 was also identified as a receptor tyrosine kinase with a “sustainer role” for the interaction of EGFR-ERBB3 and ERBB3 phosphorylation in a ROR1 kinase-independent manner, consequentially leading to PI3K activation. It was also of note that ROR1 knockdown effectively inhibited lung adenocarcinoma cell lines irrespective of their EGFR status, including those with resistance to the EGFR tyrosine kinase inhibitor gefitinib. Secondary EGFR mutation, MET amplification, and HGF overexpression may arise in lung adenocarcinomas in patients undergoing EGFR-TKI treatment, leading to treatment resistance. The existence of such diverse mechanisms makes it difficult to predict which should be targeted to prevent expansion of resistant clones. From a clinical point of view, it is thus of particular interest that ROR1 inhibition appears to be effective for treatment of gefitinib-resistant lung adenocarcinomas with various resistance mechanisms. Taken together, the present findings identify ROR1 as an “Achilles’ heel” in lung adenocarcinomas. Future development of novel therapeutic means including ROR1-specific antibodies and small molecules that inhibit both or either of the two distinct prosurvival signal-sustaining functions is greatly anticipated for attempts to reduce the intolerable death toll from currently “hard-to-cure” lung adenocarcinomas.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr LB-17. doi:1538-7445.AM2012-LB-17

NKX2-1/TITF1/TTF-1-Induced ROR1 is required to sustain EGFR survival signaling in lung adenocarcinoma

We and others previously identified NKX2-1, also known as TITF1 and TTF-1, as a lineage-survival oncogene in lung adenocarcinomas. Here we show that NKX2-1 induces the expression of the receptor tyrosine kinase-like orphan receptor 1 (ROR1), which in turn sustains a favorable balance between prosurvival PI3K-AKT and pro-apoptotic p38 signaling, in part through ROR1 kinase-dependent c-Src activation, as well as kinase activity-independent sustainment of the EGFR-ERBB3 association, ERBB3 phosphorylation, and consequential PI3K activation. Notably, ROR1 knockdown effectively inhibited lung adenocarcinoma cell lines, irrespective of their EGFR status, including those with resistance to the EGFR tyrosine kinase inhibitor gefitinib. Our findings thus identify ROR1 as an "Achilles' heel" in lung adenocarcinoma, warranting future development of therapeutic strategies for this devastating cancer.

Abstract LB-360: MYBPH, a novel transcriptional target of TTF-1/NKX2–1, inhibits ROCK1 and actomyosin assembly, and reduces cell motility and tumor metastasis

Lung cancer is the leading cause of cancer death in most economically developed countries, with lung adenocarcinoma the most prevalent form. The vast majority of lung cancer-related deaths is caused by invasion and metastasis, thus it is crucially important to elucidate the underlying mechanisms. We previously reported that lung adenocarcinomas are addicted to sustained expression of TTF-1 (also know as NKX2–1 and TITF1), a lineage-specific transcription factor required for branching morphogenesis and physiological lung functions, while others subsequently reached similar conclusions in studies that used genome-wide searches for focal genomic aberrations in lung adenocarcinomas. However, TTF-1/NKX2–1 expression is paradoxically known to be associated with favourable prognosis in lung adenocarcinoma cases.

Emerging evidence indicates that non-muscle myosin II (NM II) members, especially NM IIA, are crucially involved in cancer cell migration, invasion, and metastasis via bivalent binding to actin filaments. Rho kinase 1 (ROCK1), a downstream effecter of RhoA, has been shown to be a major positive regulator of that process, which is thought to be executed through phosphorylation of myosin regulatory light chain (RLC) and subsequent unfolding of NM IIA into an assembly competent form capable of NM IIA dimer formation. In addition, ROCK1 phosphorylates LIM domain kinase (LIMK) and stabilizes actin filaments through inactivation of the actin-depolymerising factor cofilin. However, how actomyosin organization in non-muscle cells is regulated to counter-balance the positive regulatory function of ROCK1 remains to be elucidated. Herein, we report identification of myosin binding protein H (MYBPH) as a transcriptional target of TTF-1/NKX2–1, a lineage-survival oncogene in lung adenocarcinoma. MYBPH inhibits assembly competence-conferring phosphorylation of RLC as well as activating phosphorylation of LIMK. These are unexpectedly implemented through direct physical interaction of MYBPH with ROCK1 rather than with RLC, leading to inhibition of the ROCK1 kinase activity. In addition, MYBPH is shown to directly bind with non-muscle myosin heavy chain IIA (NMHC IIA), resulting in inhibition of NMHC IIA assembly. Thus, the present findings demonstrate that MYBPH plays multi-facetted roles in negative regulation of actomyosin organization, which we find results in reduction of cell motility, invasion, and metastasis. Finally, we also show that MYBPH is epigenetically inactivated by promoter DNA methylation in a fraction of lung adenocarcinomas abundantly expressing TTF-1/NKX2–1, which appears to be in accordance with its deleterious function for lung adenocarcinoma invasion and metastasis, as well as with the paradoxical association of TTF-1/NKX2–1 expression with favourable prognosis in lung adenocarcinoma patients.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-360. doi:10.1158/1538-7445.AM2011-LB-360

Counterbalance between RB inactivation and miR-17-92 overexpression in reactive oxygen species and DNA damage induction in lung cancers

Small-cell lung cancer (SCLC) is a highly aggressive disease that exhibits rapid growth and genetic instability. We found earlier frequent overexpression of the miR-17-92 microRNA cluster, and showed that SCLC cells were addicted to continued expressions of miR-17-5p and miR-20a, major components of this microRNA cluster. In this study, we identified the frequent presence of constitutively phosphorylated H2AX (gamma-H2AX), which reflects continuing DNA damage, preferentially in SCLC. Knockdown of RB induced gamma-H2AX foci formation in non-small cell lung cancer (NSCLC) cells with wild-type RB, in association with growth inhibition and reactive oxygen species (ROS) generation, which was canceled by overexpression of miR-17-92. Conversely, induction of gamma-H2AX was observed in a miR-17-92-overexpressing SCLC cell line with miR-20a antisense oligonucleotides. These findings suggest that miR-17-92 overexpression may serve as a fine-tuning influence to counterbalance the generation of DNA damage in RB-inactivated SCLC cells, thus reducing excessive DNA damage to a tolerable level and consequently leading to genetic instability. Therefore, miR-17-92 may be an excellent therapeutic target candidate to elicit excessive DNA damage in combination with DNA-damaging chemotherapeutics.

[A case of multiple liver metastases from sigmoid colon cancer effectively treated by hepatic intra-arterial administration of levoforinate and 5-fluorouracil]

A 62-year-old female patient, who was diagnosed with sigmoid colon cancer with multiple liver metastases, was admitted to our hospital. She underwent sigmoidectomy with D3 lymph node dissection on January 31, 2000. In addition to that, she received hepatic intra-arterial infusion of levoforinate (l-LV) 250 mg and 5-fluorouracil (5-FU) 500 mg for combined multiple hepatic metastases starting on postoperative day 14, and these medications were administered over 48 hours once weekly by infuser pump. The tumor diminished by 59% 2 months after the start of administration and further diminished at 4 months. PR was achieved. Cancer metastasis to the cerebellum and metastasis to the lung were detected at month 9 and month 11, respectively, but the liver metastatic tumor continued to diminish in size, ultimately becoming undetectable by CT scan at month 10. Surgery and radiotherapy were performed for the cerebellar metastasis, and intravenous administration of a combination of l-LV and 5-FU was performed systemically for the pulmonary metastatic tumor. At present, the patient receives regular outpatient treatment continuously. To our knowledge, there has been no report on the combination therapy with l-LV and 5-FU through the hepatic artery. Since good antitumor efficacy was demonstrated in the present patient, this case is described in this report together with four other cases of hepatic metastasis from colorectal cancer.

[Arterial infusion therapy with implantable port for inoperable hepatobiliary tumors]

PURPOSE

To assess the clinical utility of arterial infusion therapy with implantable port for inoperable malignant hepatobiliary tumors.

MATERIALS AND METHODS

Twenty-seven patients with advanced hepatobiliary tumors (M:F = 14:13, mean age 63.6, 11 cases with metastases from colon cancer, 4 cases from gastric cancer, 5 cases with gallbladder cancer, 3 cases with cholangiocarcinoma, 2 cases with cholangiocellularcarcinoma, 1 case with hepatocellular carcinoma and 1 with pancreatic cancer) were treated with arterial infusion ports which were placed via left subclavian artery or femoral artery. The regimens used were FEM for 5 cases, EEP for 2 cases and FP for 20 cases.

RESULTS

Overall mean survival date was 241.8 days. The numbers of cases with CR, PR, NC and PD were 1, 6, 10 and 10, respectively, and the effective rate was 25.9%. Mean survivals of cases with cholangiocellularcarcinoma, metastases from gastric cancer and colon cancer were 715 days, 324.3 days and 245.9 days, respectively. Severe gastrointestinal side effects (> grade 3) were not observed. Serious bone marrow suppressions were frequently observed with FEM and EEP, but were rare with FP (10%).

DISCUSSION

Arterial infusion therapy with implantable port is clinically useful for advanced cholangiocancer and metastases from the gastrointestinal system. This system contributes to the quality of life of patients, since the infusion procedure is simple and can be archived in the outpatient clinics.

Phosphorylation of retinoblastoma protein at apoptotic cell death in rat neuroblastoma B50 cells

Phosphorylation of the retinoblastoma protein (RB) was observed during apoptosis of B50 neuroblastoma cells following induction by dibutyryl cAMP, after differentiation into neurons, or by cycloheximide during proliferation. A weak but distinct increase in a RB and histone H1 kinase activity was detected at the time of RB phosphorylation. However, the RB kinase appeared to correspond to neither p34cdc2 kinase, CDK2 nor CDK5 because it was not inhibited by butyrolactone I, an inhibitor for them. Expression of CDK4 and 6 along with several cyclins also did not coincide with the appearance of phosphorylated RB in the apoptotic process.

p21 expression as a predictor for favorable prognosis in squamous cell carcinoma of the lung

Although p21 WAF1/Cip1 expression has been detected immunohistochemically in non-small cell lung cancer (NSCLC), the associations between p21 expression and clinical characteristics are unknown. To determine the association between p21 expression and clinical features, p21 expression was immunohistochemically analyzed in paraffin-embedded tumor samples from 137 patients with curatively resected NSCLC. p21 expression, indicating normal p21 function, was detected in 48 (35.0%) of the 137 patients with curatively resected NSCLC and was detected more frequently in patients with stage I or II disease (40.2%) than in those with stage IIIA disease (22.5%; P = 0.0483). There was no difference in the positive rate between squamous cell carcinoma [SCC; 15 of 48 (31.3%)] and adenocarcinoma [30 of 77 (39.0%)]. For SCC, patients with tumors expressing p21 survived longer than did those with tumors negative for p21 expression; however, the corresponding survival time was not significant for adenocarcinoma. On the other hand, p53 expression, detected in 58 (42.3%) of these patients, did not act as any predictor for prognosis in either SCC or adenocarcinoma. Our findings suggest that the presence of p21 expression is associated with favorable prognosis in SCC and may be useful in obtaining candidates for adjuvant therapies from among patients with SCC.

Prognostic significance of serum p53 antibodies in squamous cell carcinoma of the lung

BACKGROUND

The prognostic significance of serum p53-Abs positivity for non-small cell lung cancer (NSCLC) is still unknown.

PATIENTS AND METHODS

To determine the prognostic value of serum p53-Abs status, we determined serum p53-Abs and immunohistochemistry in 140 patients with stage I-IIIA NSCLC.

RESULTS

p53-Abs were detected in 12.1% of all patients and in 17.6% of those with squamous cell carcinoma (SCC). Neither p53-Abs nor p53 overexpression alone was correlated with survival for all patients. When these factors were combined for SCC, seronegative patients with tumors overexpressing p53 survived significantly longer than did those with p53-Abs or p53-nonexpressing tumors. In multivariate analysis, p53-Abs status and p53 overexpression were independent prognostic factors for SCC (p = 0.0337).

CONCLUSIONS

These findings suggest that the combination of p53Abs seropositivity and p53 overexpression may be a prognostic factor for SCC.

Detection of large cell component in small cell lung carcinoma by combined cytologic and histologic examinations and its clinical implication

BACKGROUND

In the classification recently proposed by the Pathology Committee of International Association for the Study of Lung Cancer, small cell lung carcinoma (SCLC) was divided into three subtypes: pure SCLC, mixed small cell/large cell carcinoma (mixed SC/LC), and combined SCLC.

METHODS

To examine the clinical utility of this classification, histologic specimens, cytologic specimens obtained by brushing or fine-needle aspiration, and sputum cytologic specimens from 430 patients with SCLC were reviewed.

RESULTS

When the subtype of SCLC was determined from the biopsy specimen, cytologic specimen obtained by brushing or fine-needle aspiration, and sputum cytologic specimen, the frequency of mixed SC/LC was 25 of 299 (8.4%), 75 of 400 (18.8%), and 8 of 232 (3.4%), respectively. Whatever the diagnostic method, patients with mixed SC/LC showed a poorer response to treatment and worse prognosis than those with pure SCLC: a median survival of 144 days versus 285 days when classified with the use of biopsy specimens; 160 days versus 275 days with cytologic specimens obtained by brushing or fine-needle aspiration; and 47 days versus 259 days with sputum cytologic specimens, respectively.

CONCLUSIONS

These findings showed that mixed SC/LC should be separated from pure SCLC as a distinctive group and that cytologic studies of specimens obtained by brushing or fine-needle aspiration were sensitive and useful procedures for this purpose.

[A study of blood coagulation and fibrinolysis in a small-for- gestational-age infant birth group]

In order to approach from the aspect of blood coagulation and fibrinolysis the reason for the birth of SGA (small for gestational age) infants, we studied the blood coagulation and fibrinolysis capacity of maternal venous blood in the 36th and 37th weeks after conception employing 54 cases in which were no abnormality was seen during pregnancy up to delivery, and we also studied the relationship of the body weight at delivery and arrived at the following conclusions. In the SGA infant birth group there was a tendency toward acceleration of blood coagulation, acceleration of blood platelet aggregation and inhibition of fibrinolysis when compared with two other groups i.e. AGA (appropriate for gestational age) and LGA (large for gestational age) infant birth groups. In the SGA infant birth group in particular there was seen a statistically significant reduction in prothrombin time (p less than 0.002) when compared with the other two groups. A correlation was noted between prothrombin time for maternal blood and the infant's body weight at birth (r = 0.38446, p less than 0.01), and the shorter the prothrombin time for maternal blood in the late stage of pregnancy, the lower the infant's body weight tended to be at birth. The results indicate that these changes in blood coagulation and fibrinolysis may influence the decrease in the blood output of the uterine placenta, and it may be assumed that this causes the birth of SGA infants. Furthermore, the prothrombin time values become one of the parameters used in forecasting an SGA infant's birth, and this should to be considered as a new fibrinolytic therapy for SGA infants.

[Blood coagulation and fibrinolysis in cord blood with reference to birth weight]

To clarify the hemocoagulative and fibrinolytic dynamics of the perinatal period and also to seek the cause of SGA (small for gestational age) baby birth, the coagulation and fibrinolysis of the cord blood were examined, and moreover a comparison with the maternal blood, discussion on the difference in birth weight, and an examination of the difference due to the sex of babies were made in 68 cases with full-term, vaginal, spontaneous delivery, and the following conclusions were reached. In comparison with maternal blood, cord blood significantly showed any of the following: Prolongations of the prothrombin time, and the activated partial thromboplastin time, a decrease in fibrinogen, and a decrease in the platelet aggregation, antithrombin III, and plasminogen. In addition, high values for thromboxane B2 and 6-ketoprostaglandin F1 alpha were observed. In the SGA group, significant decreases were observed in the platelet count, antithrombin III, plasminogen, and alpha 2-plasmin inhibitor as compared with the AGA (appropriate for gestational age) and LGA (large for gestational age) baby groups. No sex difference was observed in the hemocoagulative and fibrinolytic capacities of the cord blood. These hemocoagulative and fibrinolytic capacities, particularly changes in the fibrinolytic system observed in the SGA group, seem to be attributable to chronic DIC (disseminated intravascular coagulation) and mild acidosis due to various stresses during pregnancy and at parturition, in turn due to immaturity of the liver in babies.