Abstract 448: Computational discovery and experimental validation of splicing-derived neoantigens

RNA splicing is a central step in the regulation of gene expression, leading to the accurate assembly of viable mRNA isoforms. Errors in the splicing process are common in cancer and lead to the production of tumor-specific mRNAs that often encode for neoantigen peptides. Such neoantigens cannot be discovered using conventional DNA-based tools; they require specialized software for alternative splicing analysis using RNA-seq data. Envisagenics has developed SpliceIOTM, a proprietary software platform for splicing-derived neoantigen discovery. SpliceIO uses RNA-seq data to uncover extracellular neoantigens encoded by transmembrane proteins or presented to immune cells through the MHC complex. Using SpliceIO, we have analyzed roughly 8,000 RNA-seq samples from 4 different cancers and 14 normal tissue types. Each dataset first undergoes an unsupervised clustering analysis using SpliceSliceTM to stratify patients into subpopulations based on similar aberrations in splicing machinery. We then leverage SpliceIO to identify splicing-derived, tumor-specific neoantigens enriched in these cohorts. SpliceIO incorporates features, such as protein localization, MHC binding affinity, epitope accessibility and cancer relevance of the gene to help select tumor specific targets with the highest therapeutic potential. Here, we summarize the discovery and validation of novel splicing-derived neoantigens identified using SpliceIO. To validate neoantigen candidates, we performed isoform expression quantification at the RNA and protein levels using PCR, RNA-FISH, western blot and mass spectrometry. Our experiments confirmed several neoantigen candidates encoded by tumor-specific RNA isoforms, that are translated and localized to the cellular membrane. Interestingly, one of the candidates is an endoplasmic reticulum protein that exhibits cassette exon skipping in approximately 24% of TNBC tumors. Fluorescence microscopy experiments demonstrate that the TNBC-specific isoform of the protein is localized to plasma membrane but not the ER, suggesting that alternative splicing can alter protein localization. Together, our results demonstrate the potential of RNA splicing analysis for the discovery of novel immunotherapeutic targets.

Citation Format: Hasan Ekrem Zumrut, Kendall Anderson, Miguel Manzanares, Shaleigh Smith, Sakshi Gera, Nayab Habib, Sanjana Shah, Devon Trahan, Martin Akerman, Gayatri Arun. Computational discovery and experimental validation of splicing-derived neoantigens [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 448.

Abstract 1873: SpliceCore® a novel ML tool for identifying disease-specific alternative splicing uncovered a promising therapeutic target for triple negative breast cancer

Accumulating evidence highlights aberrant splicing as a disease-driving event in cancer, affecting tumor progression, metastasis, and therapy resistance. Multiple studies have described the tumor-promoting activity of specific aberrant cis-splicing variants and misregulation of trans-acting splicing factors in patients. Hence, the identification of aberrant splicing patterns has the potential to translate into actionable biomarkers and novel therapeutic targets, particularly for treatment insensitive cancers such as Triple Negative Breast Cancer (TNBC). Envisagenics’ SpliceCore is an innovative cloud-based platform that integrates machine learning (ML) algorithms with high performance computing to analyze large RNA-seq datasets to predict biologically relevant, novel, and highly prevalent tumor-specific alternative splicing (AS) changes. Using SpliceCore, we have analyzed >2500 RNA-seq samples from different breast cancer subtypes as well as normal breast tissue and identified several AS derived therapeutic targets with the potential to translate into therapeutic candidates for TNBC. Here, we report a novel, alternatively spliced isoform that is present in 60.5% of TNBC patients and correlates with poor overall survival. This cytoplasmic protein was previously described as a regulator of the TGFβ pathway; therefore, we have validated the isoform switching action in a TGFβ dependent tumor progression model and demonstrated the activity of Splice Switching Oligos (SSO) to modulate its effect. We observed that this AS was correlated to a differential response on subcellular localization for phSmad2/3, Smad2/3 and TGFβRI. Pretreatment of the TNBC cells with SSO before TGFβ pathway activation modulates its proliferation response by affecting gene expression of p21, c-Myc and Smad7, leading to a decrease of cells in the G2 mitotic phase of the cell cycle and a loss of cell viability after the SSO treatment. More importantly, migratory response induced by TGFβ in TNBC cells was significantly inhibited by SSOs. Pre-treatment with SSO-0205 before TGFβ activation downregulated gene expression of Angiopoietin-like 4, Integrins α5 and β3, TGFβ associated migration markers, which was followed by a 55% decrease in cell migration. Our state-of-the-art ML technology, SpliceCore, has proven its ability to uncover novel disease-specific AS targets and to design splice correcting oligonucleotides for subsequent therapeutic development. Our data provides experimental proof of concept that has uncovered a novel therapeutic target for TNBC, whose aberrant splicing contributes to TNBC pathogenesis by misregulation of the TGFβ pathway. Moreover, SSOs predicted by SpliceCore were able to correct the aberrant splicing downstream effect, thereby uncovering a novel alternative splicing targeted approach for treating TNBC patients.

Citation Format: Miguel A. Manzanares, Alyssa Casill, Kendall Anderson, Priyanka Dhingra, Vanessa Frederick, Adam Geier, Martin Akerman, Gayatri Arun. SpliceCore® a novel ML tool for identifying disease-specific alternative splicing uncovered a promising therapeutic target for triple negative breast cancer [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 1873.

Patient-Derived Triple-Negative Breast Cancer Organoids Provide Robust Model Systems That Recapitulate Tumor Intrinsic Characteristics

Triple-negative breast cancer (TNBC) is an aggressive form of breast cancer with poor patient outcomes, highlighting the unmet clinical need for targeted therapies and better model systems. Here, we developed and comprehensively characterized a diverse biobank of normal and breast cancer patient-derived organoids (PDO) with a focus on TNBCs. PDOs recapitulated patient tumor intrinsic properties and a subset of PDOs can be propagated for long-term culture (LT-TNBC). Single cell profiling of PDOs identified cell types and gene candidates affiliated with different aspects of cancer progression. The LT-TNBC organoids exhibit signatures of aggressive MYC-driven, basal-like breast cancers and are largely comprised of luminal progenitor (LP)-like cells. The TNBC LP-like cells are distinct from normal LPs and exhibit hyperactivation of NOTCH and MYC signaling. Overall, this study validates TNBC PDOs as robust models for understanding breast cancer biology and progression, paving the way for personalized medicine and tailored treatment options.

SIGNIFICANCE

A comprehensive analysis of patient-derived organoids of TNBC provides insights into cellular heterogeneity and mechanisms of tumorigenesis at the single-cell level.

Abstract P5-17-11: Novel therapeutic target for triple negative breast cancer uncovered by SpliceCore® an innovative platform that identifies disease-specific alternative splicing

Aberrant splicing is a major hallmark of cancer, affecting tumor progression, metastasis, and therapy resistance. The oncogenic activity of specific cis splicing errors and trans-acting splicing factor misregulation in patient tumors have been demonstrated in multiple studies. As such, cancer-associated splicing dysregulation is a novel source of clinically actionable biomarkers and therapeutic targets, particularly for the treatment of insensitive cancers such as Triple Negative Breast Cancer (TNBC). Envisagenics’ SpliceCore technology is an innovative cloud-based software platform that integrates machine learning (ML) algorithms with high performance computing to analyze large RNA-seq datasets to predict biologically relevant, novel, and highly prevalent tumor specific alternative splicing (AS) changes. Using SpliceCore, we have analyzed >2500 RNAseq samples from different breast cancer subtypes as well as normal breast tissue and identified several AS targets with the potential to translate into therapeutic candidates for TNBC. Interestingly, one of our leading AS targets is an exon skipping isoform that is present in 60.5% of TNBC patients and correlates with poor overall survival, without showing differences in gene expression between all the breast cancer subtypes and healthy patients studied. In addition, SpliceCore was used to predict and design a set of splice switching oligos (SSO) that can efficiently switch the skipping isoform to an inclusion isoform in TNBC cells. The skipping isoform plays a critical role in tumor progression via a TGFβ-dependent mechanism as demonstrated by detailed isoform switching studies using SSO-0205. Pretreatment of the TNBC cells with SSO-0205 24 hours before TGFβ pathway activation modulated TGFβ pathway related protein levels and cellular localization and reversed the cell proliferative response associated with it. This resulted in a strong inhibition of p21 gene expression, accompanied by a 50% decrease on the number of cells in G2, the mitotic phase of the cell cycle, and 40% decrease on cell viability. Additionally, migratory response induced by TGFβ in TNBC cells was also significantly inhibited by SSO-0205 pretreatment, which downregulated ANGPTL4 gene expression followed by a 55% decrease in cell migration. In summary, we were able to uncover a novel therapeutic target for TNBC, whose aberrant splicing contributes to TNBC pathogenesis by promoting an overactivation of the TGFβ pathway. Our results provide experimental proof of concept that demonstrate SpliceCore’s ability to discover novel disease specific AS targets and design splice correcting oligonucleotides for subsequent therapeutic development. Reversal of this aberrant TNBC specific splicing using SSOs represent a new and promising therapeutic approach that will have a significant impact on TNBC treatment and clinical care. Moreover, SpliceCore can be applied to multiple other indications opening a new avenue for therapeutic development in cancer.

Citation Format: Miguel A Manzanares, Priyanka Dhingra, Kendall Anderson, Vanessa Frederick, Adam Geier, Alyssa Casill, Martin Akerman, Gayatri Arun. Novel therapeutic target for triple negative breast cancer uncovered by SpliceCore® an innovative platform that identifies disease-specific alternative splicing [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr P5-17-11.

Epistaxis and persistent sneezing in a Labrador Retriever dog with poorly differentiated invasive nasal squamous cell carcinoma

A Labrador Retriever was presented to University Veterinary Hospital, Kokkala with the complaint of nasal bleeding and sneezing for the last one month. Occasional left-unilateral epistaxis, persistent sneezing and facial swelling were the characteristic clinical features. Radiograph revealed mild rarefaction of bones at the cranial tip of maxilla. Biopsy and histopathology revealed pleomorphic squamous epithelial cells with feeble intercellular bridges, poor keratinization, prominent nucleoli and mitotic figures. This article reports a case of invasive nasal squamous cell carcinoma in a dog with epistaxis, persistent sneezing and facial swelling.

Abstract P170: SpliceCore® a platform for identifying aberrant alternative splicing in triple negative breast cancer for novel therapeutic development

Splicing dysregulation is a major hallmark of cancer, affecting tumor progression, metastasis, and therapy resistance. Multiple studies have demonstrated the oncogenic activity of specific cis splicing errors and trans-acting splicing factor misregulation in patient tumors. As such, cancer-associated splicing dysregulation is a novel source of clinically actionable biomarkers and therapeutic targets, particularly for treatment insensitive cancers such as TNBC. Envisagenics has developed SpliceCore, an innovative cloud-based software platform that integrates machine learning (ML) algorithms with high performance computing to analyze large RNA-seq datasets to predict biologically relevant, novel, and highly prevalent tumor specific alternative splicing (AS) changes. Using SpliceCore, we have analyzed >2500 RNAseq samples from different breast cancer subtypes as well as normal breast tissue and identified several AS targets with a potential to translate into therapeutic candidates for TNBC. Here, we will discuss one of our most promising AS targets; it is present in 60.5% of TNBC patients and correlates with poor overall survival. Using SpliceCore, we predicted and designed an optimal set of splice switching oligos (SSO) that can efficiently switch the skipping isoform to an inclusion isoform in TNBC cells. Detailed mechanism of action studies of isoform switching by SSO-0205 have demonstrated the critical role of the isoform in a TGFβ dependent tumor progression mechanism. Pretreatment of the TNBC cells with SSO-0205 24 hours before TGFβ pathway activation reversed the cell proliferative response associated with it. This resulted in a strong inhibition of p21 gene expression, accompanied by a 50% decrease on the number of cells in G2, the mitotic phase of the cell cycle, and 40% decrease on cell viability. Additionally, migratory response induced by TGFβ in TNBC cells was also significantly inhibited by SSO-0205 pretreatment, which downregulated ANGPTL4 gene expression followed by a 55% decrease in cell migration. Together, we provide experimental proof of concept to demonstrate SpliceCore’s ability to discover novel disease specific AS targets and design splice correcting oligonucleotides for subsequent correction and therapeutic development. Using this approach, we were able to uncover a novel therapeutic target for TNBC, whose aberrant splicing contributes to TNBC pathogenesis by promoting an overactivation of the TGFβ pathway. Reversal of this aberrant TNBC specific splicing using SSOs represent a new and promising therapeutic approach that will have a significant impact on TNBC treatment and clinical care.

Citation Format: Miguel A. Manzanares, Dhingra Priyanka, Kendall Anderson, Vanessa Frederick, Adam Geier, Alyssa Casill, Martin Akerman, Gayatri Arun. SpliceCore® a platform for identifying aberrant alternative splicing in triple negative breast cancer for novel therapeutic development [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2021 Oct 7-10. Philadelphia (PA): AACR; Mol Cancer Ther 2021;20(12 Suppl):Abstract nr P170.

Comprehensive analysis of structural variants in breast cancer genomes using single-molecule sequencing

Improved identification of structural variants (SVs) in cancer can lead to more targeted and effective treatment options as well as advance our basic understanding of the disease and its progression. We performed whole-genome sequencing of the SKBR3 breast cancer cell line and patient-derived tumor and normal organoids from two breast cancer patients using Illumina/10x Genomics, Pacific Biosciences (PacBio), and Oxford Nanopore Technologies (ONT) sequencing. We then inferred SVs and large-scale allele-specific copy number variants (CNVs) using an ensemble of methods. Our findings show that long-read sequencing allows for substantially more accurate and sensitive SV detection, with between 90% and 95% of variants supported by each long-read technology also supported by the other. We also report high accuracy for long reads even at relatively low coverage (25×–30×). Furthermore, we integrated SV and CNV data into a unifying karyotype-graph structure to present a more accurate representation of the mutated cancer genomes. We find hundreds of variants within known cancer-related genes detectable only through long-read sequencing. These findings highlight the need for long-read sequencing of cancer genomes for the precise analysis of their genetic instability.

MALAT1 Long Non-Coding RNA: Functional Implications

The mammalian genome is pervasively transcribed and the functional significance of many long non-coding RNA (lncRNA) transcripts are gradually being elucidated. Metastasis Associated Lung Adenocarcinoma Transcript 1 (MALAT1) is one of the most well-studied lncRNAs. MALAT1 is a highly conserved nuclear retained lncRNA that is abundantly expressed in cells and tissues and has been shown to play a role in regulating genes at both the transcriptional and post-transcriptional levels in a context-dependent manner. However, Malat1 has been shown to be dispensable for normal development and viability in mice. Interestingly, accumulating evidence suggests that MALAT1 plays an important role in numerous diseases including cancer. Here, we discuss the current state-of-knowledge in regard to MALAT1 with respect to its function, role in diseases, and the potential therapeutic opportunities for targeting MALAT1 using antisense oligonucleotides and small molecules.

A new distribution record of Albunea groeningi (Crustacea: Anomura: Decapoda: Albuneidae) from the Digha Coast, West Bengal, India

Members of the genus Albunea Weber, 1795 (family Albuneidae) are commonly known as sand crabs. Albuneidae contains 59 species belonging to 13 genera (Boyko McLaughlin 2010; WoRMS 2019), of which four genera and nine species are known only as fossils. Most species are relatively uncommon and adapted to living in sandy habitats (Boyko Harvey 1999). Among the 24 species of Albunea, four are known only as fossils (WoRMS 2019). The diversity and distributions of most albuneids were reported by Boyko (2002, 2010).

Abstract P3-11-21: Identification and characterization of novel splice variants in triple-negative breast cancer

Splicing deregulation is a major hallmark of cancer, affecting progression, metastasis and therapy resistance. Multiple studies have demonstrated the oncogenic activity of specific splicing events and splicing factors, including SRSF1, SRSF2, ESRP1, and RBFOX1, in human and animal models. As such, cancer-associated splicing deregulation may be a novel source of clinically-applicable biomarkers and therapeutic targets, particularly for treatment-insensitive cancers such as TNBC. Here, we identified and experimentally characterized novel splicing changes in triple negative breast cancer by analyzing TCGA breast cancer RNA-seq data using our software platform SpliceCore. SpliceCore integrates machine learning (ML) algorithms with high-performance computing to analyze large RNA-Seq datasets to predict biologically relevant splicing events. Our analysis of TCGA BRCA datasets has revealed several previously unknown splicing events specific to TNBC patient cohorts, that is subsequently experimentally validated in TNBC cell lines. We provide biological evidence for such TNBC specific splice-switch both at the RNA and protein level. We provide evidence for SpliceCore predicted splice-switching oligonucleotides (SSO) and verify their biological activity in TNBC cell lines. Further, functional studies using potent and specific SSOs against the top candidates reveal a critical role for some of these novel isoforms in TNBC. Together, we provide a proof of concept study using SpliceCore to identify, design, and target novel splicing changes for subsequent clinical translation and therapeutic development.

Citation Format: Gayatri Arun, Priyanka Dhingra, Robin Munch, Vanessa Fredrick, Martin Akerman. Identification and characterization of novel splice variants in triple-negative breast cancer [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P3-11-21.

MALAT1 long non-coding RNA and breast cancer

Non-coding RNAs are becoming major players in disease pathogenesis such as cancer. Metastasis Associated Lung Adenocarcinoma Transcript 1 (MALAT1) is a nuclear enriched long non-coding RNA that is generally overexpressed in patient tumors and metastases. Overexpression of MALAT1 has been shown to be positively correlated with tumor progression and metastasis in a large number of tumor types including breast tumors. Surprisingly, a recent report by Kim et al shows a metastasis suppressive role for Malat1. Here, we discuss these results in the context of a large body of published literature that support a pro-tumorigenic role for MALAT1 in order to gain potential insights into the basis of these observed differences.

Selective Small-Molecule Targeting of a Triple Helix Encoded by the Long Noncoding RNA, MALAT1

Metastasis-associated lung adenocarcinoma transcript 1 ( Malat1/ MALAT1, mouse/human), a highly conserved long noncoding (lnc) RNA, has been linked with several physiological processes, including the alternative splicing, nuclear organization, and epigenetic modulation of gene expression. MALAT1 has also been implicated in metastasis and tumor proliferation in multiple cancer types. The 3' terminal stability element for nuclear expression (ENE) assumes a triple-helical configuration that promotes its nuclear accumulation and persistent function. Utilizing a novel small molecule microarray strategy, we identified multiple Malat1 ENE triplex-binding chemotypes, among which compounds 5 and 16 reduced Malat1 RNA levels and branching morphogenesis in a mammary tumor organoid model. Computational modeling and Förster resonance energy transfer experiments demonstrate distinct binding modes for each chemotype, conferring opposing structural changes to the triplex. Compound 5 modulates Malat1 downstream genes without affecting Neat1, a nuclear lncRNA encoded in the same chromosomal region as Malat1 with a structurally similar ENE triplex. Supporting this observation, the specificity of compound 5 for Malat1 over Neat1 and a virus-coded ENE was demonstrated by nuclear magnetic resonance spectroscopy. Small molecules specifically targeting the MALAT1 ENE triplex lay the foundation for new classes of anticancer therapeutics and molecular probes for the treatment and investigation of MALAT1-driven cancers.

Modulatory effect of 900 MHz radiation on biochemical and reproductive parameters in rats

In the present study, the effect of 900 MHz radiation exposure on blood biochemical and reproductive parameters was evaluated in adolescent rats. Male albino Wistar rats (8-10 weeks of age) were exposed to 900 MHz radiation (1hr/day, power density - 146.60 µW/cm2) from a mobile phone for 28 days. On 29th day the animals were euthanized and malondialdehyde (MDA), total antioxidants (TA) levels and Glutathione-S transferase (GST) activity were studied in the blood. Reproductive parameters such as total sperm count, percentage of non-motile sperms, and sperm morphology were determined. Testes sections were stained with H(et)E staining and their cellular integrity was evaluated. Caspase-3 activity in the testes was also determined. MDA concentration was increased but TA levels and GST activity were not found to be different in 900 MHz group compared to controls. Sperm motility was found to be slightly reduced in 900 MHz group. Percentage of abnormal sperm was significantly elevated in 900 MHz group. Additionally, loss of germ cells particularly spermatocytes and spermatids was found in the testes of 900 MHz group. Testes caspase-3 activity was slightly elevated in 900 MHz exposed rats. Chronic 900 MHz exposure induced oxidative damage in the blood and lead to alterations in reproductive parameters in rats (Fig. 4, Ref. 33).

Morphological variations in marine pufferfish and porcupinefish (Teleostei: Tetraodontiformes) from Tamil Nadu, southeastern coast of India

In the present study, morphological variations in 14 species of two families, Tetraodontidae and Diodontidae, were examined for individuals collected from five different centres in Tamil Nadu in the southeastern coast of India.  Twenty-seven morphological measurements and four meristic characters were taken and used for multivariate analyses such as discriminant function analysis (DFA) & MANOVA.  DFA revealed that the first two functions accounted for more than 75% variation between the species.  Negative allometric values were observed on head length (HL), orbital length (OL), pupil diameter (PD), interorbital length (IOL), pectoral-fin length (PEL), caudal peduncle depth (CPD), dorsal to pectoral fin distance (DPFD), caudal peduncle length (CPL) and post-pectoral-fin length (POPFL) measurements.  Also, MANOVA supported the DFA results.  Additions, allometric relationships, and meristic variations were observed for most of these species.   Moreover, this is the first attempt to describe a greater number of morphological features of the species belonging to the order Tetraodontiformes.

POU2F3 is a master regulator of a tuft cell-like variant of small cell lung cancer

Small cell lung cancer (SCLC) is widely considered to be a tumor of pulmonary neuroendocrine cells; however, a variant form of this disease has been described that lacks neuroendocrine features. Here, we applied domain-focused CRISPR screening to human cancer cell lines to identify the transcription factor (TF) POU2F3 (POU class 2 homeobox 3; also known as SKN-1a/OCT-11) as a powerful dependency in a subset of SCLC lines. An analysis of human SCLC specimens revealed that POU2F3 is expressed exclusively in variant SCLC tumors that lack expression of neuroendocrine markers and instead express markers of a chemosensory lineage known as tuft cells. Using chromatin- and RNA-profiling experiments, we provide evidence that POU2F3 is a master regulator of tuft cell identity in a variant form of SCLC. Moreover, we show that most SCLC tumors can be classified into one of three lineages based on the expression of POU2F3, ASCL1, or NEUROD1. Our CRISPR screens exposed other unique dependencies in POU2F3-expressing SCLC lines, including the lineage TFs SOX9 and ASCL2 and the receptor tyrosine kinase IGF1R (insulin-like growth factor 1 receptor). These data reveal POU2F3 as a cell identity determinant and a dependency in a tuft cell-like variant of SCLC, which may reflect a previously unrecognized cell of origin or a trans-differentiation event in this disease.

Therapeutic Targeting of Long Non-Coding RNAs in Cancer

Long non-coding RNAs (lncRNAs) represent a significant population of the human transcriptome. Many lncRNAs exhibit cell- and/or tissue/tumor-specific expression, making them excellent candidates for therapeutic applications. In this review we discuss examples of lncRNAs that demonstrate the diversity of their function in various cancer types. We also discuss recent advances in nucleic acid drug development with a focus on oligonucleotide-based therapies as a novel approach to inhibit tumor progression. The increased success rates of nucleic acid therapeutics provide an outstanding opportunity to explore lncRNAs as viable therapeutic targets to combat various aspects of cancer progression.

Fractured Tracheostomy Tube - An Unusual Foreign Body in Tracheobronchial Tree

Introduction Approximately 20% of patients with tracheostomy are discharged from hospital with the tracheostomy  tube in situ. Proper long term care and management of such tracheostomy patients remains as a challenge to care givers. Fracture of metallic tracheostomy tube (TT) with aspiration of the fragment into tracheobronchial airway is a rare complication of  tracheostomy. Case Report Here we are presenting a case of a 42-year-old male patient, presented to the emergency department with complaint of mild respiratory distress following aspiration of fractured metallic TT and a novel method in removing the dislodged fragment. Discussion A detailed review of literature has been included to discuss different aspects of aspiration of fractured fragment of tracheostomy tube and best practice recommendations for proper tracheostomy care. Conclusion Educating the care-giver about care of the tracheostomized patient in general and care of the tracheostomy tube in particular, may help reduce accidental complications.

Growth Hormone Treatment in Turner's Syndrome: A Real World Experience

OBJECTIVE

Short stature is a universal clinical feature of Turner's syndrome (TS). Growth failure begins in fetal life, and adults with TS are on an average 20 cm shorter than the normal female population. Since there is a paucity of data from India regarding the effect of growth hormone (GH) on TS patients, we retrospectively analyzed the data of TS patients who are on GH treatment.

METHODS

This hospital-based observational retrospective study was conducted in a tertiary care hospital of Hyderabad. The data such as height, weight, and bone age of 16 patients who are diagnosed with TS on GH therapy for at least 6 months were included in the study. All the patients were treated with human recombinant GH at the dose of 0.3 mg/kg/week administered as daily subcutaneous injections.

RESULTS

The mean age at diagnosis was 12.7 years. The mean height at the start of GH therapy was 1.26 m, and mean height standard deviation score (HSDS) was-0.61 when compared to Turner's specific reference data. With a mean duration of GH therapy of 25 months, the mean height at the end of therapy was 1.37 m and the mean height as per HSDS was + 0.37 resulting in a mean height gain of + 0.99 HSDS.

CONCLUSION

Our observation shows that girls with TS benefit from early diagnosis and initiation of treatment with GH.

Promotion of sanitation and hygiene in a rural area of South India: A community-based study

INTRODUCTION

Globally, billions of people do not have access to improved sanitation and many defecate in the open air. Poor hand washing practices and limited access to sanitation facilities perpetuate the transmission of disease-causing germs. The objectives of the study were to find out the level of knowledge, attitudes, and practices (KAPs) on sanitary latrine, footwear, and hand washing among rural people and to assess the improvement in KAP after health education intervention.

MATERIALS AND METHODS

A health education intervention study was conducted from November 2012 to January 2014 in a rural area of Kuppam, Andhra Pradesh, South India among the people aged 15 years and above. The individuals were selected by multistage random sampling and interviewed using a structured questionnaire. After a baseline KAP assessment, intervention activities were conducted twice. The intervention activities were group level talks and discussions, free soap distribution, and display of posters at anganwadi centers. Post-KAP was assessed twice, and the significance of difference was found by using McNemar's test.

RESULTS

After the intervention, there was a significant improvement in the overall KAPs among the subjects in post test-1 and post test-2 (P₁ < 0.0001, P₂ < 0.0001), respectively.

CONCLUSIONS

Health education as an intervention has significantly increased KAP more than 30%. Hence, it is imperative that education interventions are needed to bring or sustain positive change.

Abstract PR11: Differentiation of mammary tumors and reduction in metastasis upon Malat1 LncRNA loss

Genome-wide studies have identified thousands of long non-coding RNAs (lncRNAs) lacking protein-coding capacity. MALAT1 (Metastasis Associated Lung Adenocarcinoma Transcript 1) is among the most abundant and highly conserved nuclear restricted lncRNAs whose expression is mis-regulated in many cancers including breast cancer. RNA-FISH experiments on primary tumor and metastatic nodules from patients with luminal type breast cancer revealed that MALAT1 lncRNA is 4-5 times up regulated in metastatic nodules compared to primary tumors. This strongly suggests that MALAT1 plays an important role in the metastatic progression of luminal breast cancers. We have used the MMTV-PyMT mouse model of luminal B breast cancer to characterize the role of Malat1 in primary breast cancer and its subsequent metastasis. Malat1 lncRNA was knocked down via subcutaneous administration of antisense oligonucleotides (ASOs) at a dose of 125mg/kg/week over a period of 7 weeks after which animals were sacrificed and primary tumors and lungs were removed for molecular and histological analyses. Malat1 ASO treatment resulted in ~60% knockdown in the primary tumor concomitant with a significant reduction in tumor progression rate as well as a change in the differentiation status. Detailed histo-pathological analysis of ASO treated tumors showed an increase in well-differentiated ductular tumors, whereas scrambled ASO treated tumors progressed to solid carcinomas. Most interestingly, a marked decrease was observed in the incidence of lung metastases; ~70% fewer metastatic nodules in Malat1 ASO treated animals than scrambled ASO treated animals. Further, Malat1 ASO treated ex-vivo generated mammary gland organoids from MMTV-PyMT mice, resulted in an inhibition of branching morphogenesis, which recapitulates the invasive process that initiate metastases in vivo. RNA-seq analysis of the primary tumors and tumor derived organoids treated with Malat1 ASO showed up-regulation of genes involved in differentiation and down regulation of genes involved in migration and proliferation. Further, Malat1 knock-down also resulted in aberrant splicing of many genes including critical transcription factors. Together, our data indicates that Malat1 lncRNA regulates critical processes in breast cancer pathogenesis and represents a promising therapeutic target for treatment.

This abstract is also presented as Poster B02.

Citation Format: Gayatri Arun, Sarah Diermeier, Martin Akerman, Kung-Chi Chang, J.Erby Wilkinson, Stephen Hearn, Youngsoo Kim, A.Robert MacLeod, Adrian R. Krainer, Larry Norton, Edi Brogi, Mikala Egeblad, David L. Spector. Differentiation of mammary tumors and reduction in metastasis upon Malat1 LncRNA loss. [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 PR11.

Differentiation of mammary tumors and reduction in metastasis upon Malat1 lncRNA loss

Genome-wide analyses have identified thousands of long noncoding RNAs (lncRNAs). Malat1 (metastasis-associated lung adenocarcinoma transcript 1) is among the most abundant lncRNAs whose expression is altered in numerous cancers. Here we report that genetic loss or systemic knockdown of Malat1 using antisense oligonucleotides (ASOs) in the MMTV (mouse mammary tumor virus)-PyMT mouse mammary carcinoma model results in slower tumor growth accompanied by significant differentiation into cystic tumors and a reduction in metastasis. Furthermore, Malat1 loss results in a reduction of branching morphogenesis in MMTV-PyMT- and Her2/neu-amplified tumor organoids, increased cell adhesion, and loss of migration. At the molecular level, Malat1 knockdown results in alterations in gene expression and changes in splicing patterns of genes involved in differentiation and protumorigenic signaling pathways. Together, these data demonstrate for the first time a functional role of Malat1 in regulating critical processes in mammary cancer pathogenesis. Thus, Malat1 represents an exciting therapeutic target, and Malat1 ASOs represent a potential therapy for inhibiting breast cancer progression.

Characterization and biological activities of extracellular melanin produced by Schizophyllum commune (Fries)

Melanins are enigmatic pigments produced by a wide variety of microorganisms including bacteria and fungi. Here, we have isolated and characterized extracellular melanin from mushroom fungus, Schizophyllum commune. The extracellular dark pigment produced by the broth culture of S. commune, after 21 days of incubation was recovered by hot acid-alkali treatment. The melanin nature of the pigment was characterized by biochemical tests and further, confirmed by UV, IR, EPR, NMR and MALDI-TOF Mass Spectra. Extracellular melanin, at 100 μg/ml, showed significant antibacterial activity against Escherichia coli, Bacillus subtilis, Klebsiella pneumoniae and Pseudomonas fluorescens and antifungal activity against Trichophyton simii and T. rubrum. At a concentration of 50 μg/ml, melanin showed high free radical scavenging activity of DPPH (2,2-diphenyl-1-picrylhydrazyl) indicating its antioxidant potential. It showed concentration dependent inhibition of cell proliferation of Human Epidermoid Larynx Carcinoma Cell Line (HEP-2). This study has demonstrated characterization of melanin from basidiomycetes mushroom fungus, Schizophyllum commune and its applications.

Genome wide chromatin occupancy of mrhl RNA and its role in gene regulation in mouse spermatogonial cells

Mrhl RNA is a nuclear lncRNA encoded in the mouse genome and negatively regulates Wnt signaling in spermatogonial cells through p68/Ddx5 RNA helicase. Mrhl RNA is present in the chromatin fraction of mouse spermatogonial Gc1-Spg cells and genome wide chromatin occupancy of mrhl RNA by ChOP (Chromatin oligo affinity precipitation) technique identified 1370 statistically significant genomic loci. Among these, genes at 37 genomic loci also showed altered expression pattern upon mrhl RNA down regulation which are referred to as GRPAM (Genes Regulated by Physical Association of Mrhl RNA). p68 interacted with mrhl RNA in chromatin at these GRPAM loci. p68 silencing drastically reduced mrhl RNA occupancy at 27 GRPAM loci and also perturbed the expression of GRPAM suggesting a role for p68 mediated mrhl RNA occupancy in regulating GRPAM expression. Wnt3a ligand treatment of Gc1-Spg cells down regulated mrhl RNA expression and also perturbed expression of these 27 GRPAM genes that included genes regulating Wnt signaling pathway and spermatogenesis, one of them being Sox8, a developmentally important transcription factor. We also identified interacting proteins of mrhl RNA associated chromatin fraction which included Pc4, a chromatin organizer protein and hnRNP A/B and hnRNP A2/B1 which have been shown to be associated with lincRNA-Cox2 function in gene regulation. Our findings in the Gc1-Spg cell line also correlate with the results from analysis of mouse testicular tissue which further highlights the in vivo physiological significance of mrhl RNA in the context of gene regulation during mammalian spermatogenesis.

Abstract 1121: The long non-coding RNA MALAT1 is an essential gene regulator for lung cancer metastasis in a novel human knockout model

The long non-coding RNA MALAT1 was one of the first lncRNAs associated with cancer: it is a highly conserved nuclear ncRNA and a predictive marker for metastasis development in lung cancer. However, its high abundance and nuclear localization have greatly hampered its functional analysis since it is only inefficiently knocked down by RNA interference (RNAi).

To uncover its functional importance, we developed a MALAT1 knockout model in human lung tumor cells by genomically integrating RNA destabilizing elements site-specifically into the MALAT1 locus using Zinc Finger Nucleases (ZFN).This approach yielded a more than 1000-fold silencing of MALAT1 providing a unique loss-of-function model.

Proposed mechanisms of action of MALAT1 include regulation of splicing or gene expression. In lung cancer, MALAT1 does not alter alternative splicing but actively regulates gene expression inducing a signature of metastasis-associated genes. Consequently, MALAT1-deficient cells are impaired in migration and form fewer tumor nodules in a mouse xenograft model.

Encouraged by this discovery of the essential function of MALAT1 in lung cancer metastasis, we wanted to analyze whether MALAT1 could also be therapeutically targeted: We developed Antisense oligonucleotides (ASOs) effectively blocking MALAT1 expression in the cell culture and in the animal. Notably, MALAT1-ASO treatment prevents metastasis formation after tumor implantation. Thus, targeting MALAT1 with antisense oligonucleotides provides a potential therapeutic approach to prevent lung cancer metastasis with MALAT1 serving as both, predictive marker and therapeutic target.

Lastly, regulating gene expression, but not alternative splicing is the critical function of MALAT1 in lung cancer metastasis.

In summary, ten years after the discovery of the lncRNA MALAT1 as a biomarker for lung cancer metastasis, our loss-of-function model unravels the active function of MALAT1 as a regulator of gene expression governing hallmarks of lung cancer metastasis.

Citation Format: Tony Gutschner, Monika Hämmerle, Moritz Eißmann, Jeff Hsu, Youngsoo Kim, Gene Hung, Alexey Revenko, Gayatri Arun, Marion Stentrup, Matthias Groß, Martin Zörnig, A. Robert MacLeod, David L. Spector, Sven Diederichs. The long non-coding RNA MALAT1 is an essential gene regulator for lung cancer metastasis in a novel human knockout model . [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1121. doi:10.1158/1538-7445.AM2013-1121

The noncoding RNA MALAT1 is a critical regulator of the metastasis phenotype of lung cancer cells

The long noncoding RNA MALAT1 (metastasis-associated lung adenocarcinoma transcript 1), also known as MALAT-1 or NEAT2 (nuclear-enriched abundant transcript 2), is a highly conserved nuclear noncoding RNA (ncRNA) and a predictive marker for metastasis development in lung cancer. To uncover its functional importance, we developed a MALAT1 knockout model in human lung tumor cells by genomically integrating RNA destabilizing elements using zinc finger nucleases. The achieved 1,000-fold MALAT1 silencing provides a unique loss-of-function model. Proposed mechanisms of action include regulation of splicing or gene expression. In lung cancer, MALAT1 does not alter alternative splicing but actively regulates gene expression including a set of metastasis-associated genes. Consequently, MALAT1-deficient cells are impaired in migration and form fewer tumor nodules in a mouse xenograft. Antisense oligonucleotides (ASO) blocking MALAT1 prevent metastasis formation after tumor implantation. Thus, targeting MALAT1 with ASOs provides a potential therapeutic approach to prevent lung cancer metastasis with this ncRNA serving as both predictive marker and therapeutic target. Finally, regulating gene expression, but not alternative splicing, is the critical function of MALAT1 in lung cancer metastasis. In summary, 10 years after the discovery of the lncRNA MALAT1 as a biomarker for lung cancer metastasis, our loss-of-function model unravels the active function of MALAT1 as a regulator of gene expression governing hallmarks of lung cancer metastasis.

The lncRNA Malat1 is dispensable for mouse development but its transcription plays a cis-regulatory role in the adult

Genome-wide studies have identified thousands of long noncoding RNAs (lncRNAs) lacking protein-coding capacity. However, most lncRNAs are expressed at a very low level, and in most cases there is no genetic evidence to support their in vivo function. Malat1 (metastasis associated lung adenocarcinoma transcript 1) is among the most abundant and highly conserved lncRNAs, and it exhibits an uncommon 3'-end processing mechanism. In addition, its specific nuclear localization, developmental regulation, and dysregulation in cancer are suggestive of it having a critical biological function. We have characterized a Malat1 loss-of-function genetic model that indicates that Malat1 is not essential for mouse pre- and postnatal development. Furthermore, depletion of Malat1 does not affect global gene expression, splicing factor level and phosphorylation status, or alternative pre-mRNA splicing. However, among a small number of genes that were dysregulated in adult Malat1 knockout mice, many were Malat1 neighboring genes, thus indicating a potential cis-regulatory role of Malat1 gene transcription.

SU-E-T-516: Dosimetric Validation of AcurosXB Algorithm in Comparison with AAA & CCC Algorithms for VMAT Technique

PURPOSE

To dosimetrically validate AcurosXB algorithm for Volumetric Modulated Arc Therapy (VMAT) in comparison with standard clinical Anisotropic Analytic Algorithm(AAA) and Collapsed Cone Convolution(CCC) dose calculation algorithms.

METHODS

AcurosXB dose calculation algorithm is available with Varian Eclipse treatment planning system (V10). It uses grid-based Boltzmann equation solver to predict dose precisely in lesser time. This study was made to realize algorithms ability to predict dose accurately as its delivery for which five clinical cases each of Brain, Head&Neck, Thoracic, Pelvic and SBRT were taken. Verification plans were created on multicube phantom with iMatrixx-2D detector array and then dose prediction was done with AcurosXB, AAA & CCC (COMPASS System) algorithm and the same were delivered onto CLINAC-iX treatment machine. Delivered dose was captured in iMatrixx plane for all 25 plans. Measured dose was taken as reference to quantify the agreement between AcurosXB calculation algorithm against previously validated AAA and CCC algorithm. Gamma evaluation was performed with clinical criteria distance-to-agreement 3&2mm and dose difference 3&2% in omnipro-I'MRT software. Plans were evaluated in terms of correlation coefficient, quantitative area gamma and average gamma.

RESULTS

Study shows good agreement between mean correlation 0.9979±0.0012, 0.9984±0.0009 & 0.9979±0.0011 for AAA, CCC & Acuros respectively. Mean area gamma for criteria 3mm/3% was found to be 98.80±1.04, 98.14±2.31, 98.08±2.01 and 2mm/2% was found to be 93.94±3.83, 87.17±10.54 & 92.36±5.46 for AAA, CCC & Acuros respectively. Mean average gamma for 3mm/3% was 0.26±0.07, 0.42±0.08, 0.28±0.09 and 2mm/2% was found to be 0.39±0.10, 0.64±0.11, 0.42±0.13 for AAA, CCC & Acuros respectively.

CONCLUSIONS

This study demonstrated that the AcurosXB algorithm had a good agreement with the AAA & CCC in terms of dose prediction. In conclusion AcurosXB algorithm provides a valid, accurate and speedy alternative to AAA and CCC algorithms in a busy clinical environment.

Bilateral thalamic necrosis following ingestion of ridge gourd infested with coelomycete fungi (Diplodia)

Bilateral thalamic lesions detected on magnetic resonance imaging have a wide differential diagnosis. This report describes a previously healthy young man who developed bilateral thalamic necrosis with seizures, vomiting, hepatitis, neutrophilic leukocytosis and metabolic acidosis following consumption of raw dried fruits of the ridge gourd plant (Luffa acutangula) prescribed by a traditional medicine practitioner. These fruits were subsequently shown to be infested with spores and conidiomata of Diplodia, a coelomycete fungus known to cause neurotoxicity in farm animals. The patient made a partial recovery with supportive care, and has persistent deficits consistent with bilateral medial thalamic damage. This is the first report of neurological toxicity attributable to Diplodia in humans, and this entity should be considered in the differential diagnosis of bilateral thalamic lesions in the appropriate clinical setting.