Antimalarial potential, LC-MS secondary metabolite profiling and computational studies of Zingiber officinale

Malaria is among the top-ranked parasitic diseases that pose a threat to the existence of the human race. This study evaluated the antimalarial effect of the rhizome of Zingiber officinale in infected mice, performed secondary metabolite profiling and detailed computational antimalarial evaluation through molecular docking, molecular dynamics (MD) simulation and density functional theory methods. The antimalarial potential of Z. officinale was performed using the in vivo chemosuppressive model; secondary metabolite profiling was carried out using liquid chromatography-mass spectrometry (LC-MS). Molecular docking was performed with Autodock Vina while the MD simulation was performed with Schrodinger desmond suite for 100 ns and DFT calculations with B3LYP (6-31G) basis set. The extract showed 64% parasitaemia suppression, with a dose-dependent increase in activity up to 200 mg/kg. The chemical profiling of the extract tentatively identified eight phytochemicals. The molecular docking studies with plasmepsin II and Plasmodium falciparum dihydrofolate reductase-thymidylate synthase (PfDHFR-TS) identified gingerenone A as the hit molecule, and MMGBSA values corroborate the binding energies obtained. The electronic parameters of gingerenone A revealed its significant antimalarial potential. The antimalarial activity elicited by the extract of Z. officinale and the bioactive chemical constituent supports its usage in ethnomedicine.Communicated by Ramaswamy H. Sarma.

Recurring SARS-CoV-2 variants: an update on post-pandemic, co-infections and immune response

The post-pandemic era following the global spread of the SARS-CoV-2 virus has brought about persistent concerns regarding recurring coinfections. While significant strides in genome mapping, diagnostics, and vaccine development have controlled the pandemic and reduced fatalities, ongoing virus mutations necessitate a deeper exploration of the interplay between SARS-CoV-2 mutations and the host's immune response. Various vaccines, including RNA-based ones like Pfizer and Moderna, viral vector vaccines like Johnson & Johnson and AstraZeneca, and protein subunit vaccines like Novavax, have played critical roles in mitigating the impact of COVID-19. Understanding their strengths and limitations is crucial for tailoring future vaccines to specific variants and individual needs. The intricate relationship between SARS-CoV-2 mutations and the immune response remains a focus of intense research, providing insights into personalized treatment strategies and long-term effects like long-COVID. This article offers an overview of the post-pandemic landscape, highlighting emerging variants, summarizing vaccine platforms, and delving into immunological responses and the phenomenon of long-COVID. By presenting clinical findings, it aims to contribute to the ongoing understanding of COVID-19's progression in the aftermath of the pandemic.

Long Non-Coding RNAs: New Insights in Neurodegenerative Diseases

Neurodegenerative diseases (NDDs), including Alzheimer's disease (AD), Parkinson's disease (PD), and amyotrophic lateral sclerosis (ALS), are gradually becoming a burden to society. The adverse effects and mortality/morbidity rates associated with these NDDs are a cause of many healthcare concerns. The pathologic alterations of NDDs are related to mitochondrial dysfunction, oxidative stress, and inflammation, which further stimulate the progression of NDDs. Recently, long non-coding RNAs (lncRNAs) have attracted ample attention as critical mediators in the pathology of NDDs. However, there is a significant gap in understanding the biological function, molecular mechanisms, and potential importance of lncRNAs in NDDs. This review documents the current research on lncRNAs and their implications in NDDs. We further summarize the potential implication of lncRNAs to serve as novel therapeutic targets and biomarkers for patients with NDDs.

A Systems Biology Approach Unveils a Critical Role of DPP4 in Upper Gastrointestinal Cancer Patient Outcomes

Gastrointestinal (GI) cancers comprise of cancers that affect the digestive system and its accessory organs. The late detection and poor prognosis of GI cancer emphasizes the importance of identifying reliable and precise biomarkers for early diagnosis and prediction of prognosis. The membrane-bound glycoprotein dipeptidyl-peptidase 4 (DPP4), also known as CD26, is ubiquitously expressed and has a wide spectrum of biological roles. The role of DPP4/CD26 in tumor progression in different types of cancers remains elusive. However, the link between DPP4 and tumor-infiltrating cells, as well as its prognostic significance in malignancies, still require further investigation. This study was intended to elucidate the correlation of DPP4 expression and survival along with prognosis, followed by its associated enriched molecular pathways and immune cell marker levels in upper GI cancers. Results demonstrated a strong correlation between increased DPP4 expression and a worse prognosis in esophageal and gastric cancer and the co-expressed common genes with DPP4 were associated with crucial molecular pathways involved in tumorigenesis. Additionally, DPP4 was shown to be significantly linked to several immune infiltrating cell marker genes, including Macrophages (M1, M2 and Tumor Associated Macrophages), neutrophils, Treg, T-cell exhaustion, Th1 and Th2. Overall, our findings suggest that DPP4 may serve as a substantial prognostic biomarker, a possible therapeutic target, as well as it can play a critical role in the regulation of immune cell invasion in patients with gastroesophageal (esophageal, gastroesophageal junction and gastric) cancer. KEY WORDS: DPP4, integrated analysis, GI cancer, gastroesophageal cancer, gastroesophageal junction, prognosis.

MUC13 drives cancer aggressiveness and metastasis through the YAP1-dependent pathway

Anchorage-independent survival after intravasation of cancer cells from the primary tumor site represents a critical step in metastasis. Here, we reveal new insights into how MUC13-mediated anoikis resistance, coupled with survival of colorectal tumor cells, leads to distant metastasis. We found that MUC13 targets a potent transcriptional coactivator, YAP1, and drives its nuclear translocation via forming a novel survival complex, which in turn augments the levels of pro-survival and metastasis-associated genes. High expression of MUC13 is correlated well with extensive macrometastasis of colon cancer cells with elevated nuclear YAP1 in physiologically relevant whole animal model systems. Interestingly, a positive correlation of MUC13 and YAP1 expression was observed in human colorectal cancer tissues. In brief, the results presented here broaden the significance of MCU13 in cancer metastasis via targeting YAP1 for the first time and provide new avenues for developing novel strategies for targeting cancer metastasis.

Abstract 1281: Oncoprotein YB-1 modulation of Lyn-MAPK-NF-kB pathway, a potential therapeutic strategy combined with sorafenib for advanced stage HCC

The Y-Box Binding protein 1 (YB-1) is a 324 amino acid-long member of the Cold Shock Domain (CSD) protein superfamily. YB-1 interacts with micro RNAs and non-coding RNAs in the cytoplasm, acting as a regulator of mRNA translation. YB-1 translocation into the nucleus is circadian clock-dependent and leads to the upregulation of cyclin gene expression, among others. Another mechanism of nuclear translocation of YB-1 is mediated by phosphorylation of the Ser 102 residue in the CSD. The YB-1 oncoprotein acts as a transcription factor when bound to DNA, modulating the transcription of genes that regulate biological processes such as Multidrug Resistance Mutation 1 (MDR1). YB-1 is linked to poor prognosis in breast, prostate, and liver cancer. Despite advances in biomedicine, the incidence and mortality of hepatocellular carcinoma (HCC) remain high. Sorafenib, a tyrosine kinase Inhibitor (TKI), is the first-line treatment for advanced HCC. Sorafenib also inhibits downstream activation of NF-kB by inhibition of Lyn phosphorylation (Y397). However, it was observed in many patients that its sorafenib’s effectiveness is hampered by drug resistance, but the mechanism is still unclear. We have found that SK-HEP-1 HCC cells transfected with a YB-X-1 overexpression plasmid subsequently developed into a stable YB-1 overexpression cell line (SK-HEP-1+YB-1) displayed increased invasion, migration, proliferation, and colony formation property as compared to the vector control (SKHEP1+Vec). The SK-HEP-1+YB-1 cell line also showed increased IC50 for sorafenib and elevated phosphorylation of Lyn (Y397) and further activated NF-kB (S165/S176) phosphorylation. This indicates YB-1 may cause increased Sorafenib resistance in HCC by activating tyrosine kinases (TK), such as lyn, and simultaneous activation of NF-kB. The combination of YB-1 inhibition and sorafenib might provide a novel therapeutic strategy and improve the survival of patients with advanced-stage HCC.

Citation Format: Ana G. Ayala Pazzi, Omar Karkoutly, Kristopher Ezell, Samantha Lopez, Kyle D. Doxtater, Elias George, Vijian Dhevan, Manish K. Tripathi. Oncoprotein YB-1 modulation of Lyn-MAPK-NF-kB pathway, a potential therapeutic strategy combined with sorafenib for advanced stage HCC [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 1281.

Abstract 2854: LncRNA UCA1 as a potential therapeutic target for drug resistance in colorectal cancer

Cancer metastasis is one of the deadliest aspects of the disease, with about 90% of all cancer-related deaths due to its development at different sites within the body. Colorectal cancer (CRC) is the second leading cause of cancer mortality in the United States, with 40-50% of all patients developing metastasis at some point during their fight with the disease. With the approval of Regorafenib for treating metastatic colorectal cancer, steps have been taken to combat metastasis in colorectal cancer. A vital aspect of the development of metastasis is the development of resistance to first-line chemotherapy. Regorafenib is an oral small-molecule multiple kinase inhibitor. It is indicated worldwide for patients with metastatic colorectal cancer (mCRC), Regorafenib has already begun to show resistance in CRC. Understanding the mechanisms behind Regorafenib resistance in CRC is vital. Studies have demonstrated the expression of Long-non-coding RNA (LncRNA) to be linked to cancer metastasis and drug resistance. LncRNA UCA1 has been shown in other cancers to lead to resistance to different drugs like cisplatin, gemcitabine, 5-FU, tamoxifen, imatinib, and EGFR-TKIs. In our lab, we have found the LncRNA UCA1 to be overexpressed in CRC patient tissues, with increasing expression across stages I-III, compared to normal tissue. High UCA1 expression has decreased survival among colorectal cancer patients, per the TCGA patient cohort analysis. Furthermore, we found that high UCA1 expression in colorectal cancer cell lines leads to high IC50 values for Regorafenib. Lentiviral transduce stable overexpression (SW480), and knockdown (SW620) cell lines were developed for UCA1-regorafenib drug resistance mechanistic studies. Increased expression of UCA1 led to increased expression of crucial drug resistance genes (MDR1, ABCB1, and FOXM1) and increased IC50 compared to the control vector. In contrast, the knockdown of UCA1 led to decreased expression of resistance markers and IC50 in SW620 cells. A 3D spheroid model was utilized to assay regorafenib sensitivity to the UCA1 overexpressed and knockdown cell lines. High UCA1 expression leads to the formation of a higher number of 3D spheroid bodies and size when compared to vector. Furthermore, when treating the spheroid with IC50 concentration, UCA1 overexpressing spheroids showed higher vitality and increased size compared to the vector control. We have also analyzed the signaling pathways modulated by UCA1 in CRC cell lines, which may be involved in enhancing the regorafenib resistance. This supports the notion that UCA1 is critical in enhancing the resistance to regorafenib in CRC by activating drug resistance pathways. For the first time, this study demonstrates that UCA1 provides drug resistance to regorafenib in CRC, facilitating the progression of CRC metastasis.

Citation Format: Kyle D. Doxtater, Manish K. Tripathi. LncRNA UCA1 as a potential therapeutic target for drug resistance in colorectal cancer [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 2854.

Abstract 1291: Signaling pathways modulated by lncRNA UCA1 during anchorage-independent growth in colorectal cancer

Colorectal cancer (CRC) is the second deadliest cancer, and over 40-50% of patients develop metastasis during their fight against the disease. CRC survival rate drops from 90% to 14% when the condition is contained within the colon vs. when found at distant sites within the body. Metastasis is a multistep process and one of the critical steps for cancer cells to acquire anoikis resistance to survive after detachment from the primary sites and travel through the circulatory and lymphatic systems to distant target organs. Thus, understanding the molecular players involved in the anoikis process and metastasis could be vital for improving the survival of CRC patients. The aberrant expression of a long noncoding RNA (lncRNA) urothelial carcinoma-associated 1 (UCA1) has been identified in CRC. However, its role in metastasis processes is not yet well defined. Our preliminary results in the anchorage-independent growth (anoikis model) demonstrate increased expression of lncRNA UCA1. Moreover, the overexpression of lncRNA UCA1 led to high expression of stemness markers SOX2 and Kaiso, along with increased survival of anchorage-independent cells, which indicates a potential mechanistic role of UCA1 in anoikis resistance. Thus, in this study, we propose elucidating the role(s) of UCA1 and its associated signaling pathways during anoikis resistance. We hypothesize that the overexpression of lncRNA UCA1 enhances CRC metastasis through anoikis resistance-associated signaling pathways. We will utilize Isogenic CRC cell lines SW480 (oncogenic) and SW620 (metastatic) to understand the mechanistic regulation of anoikis resistance. Lentiviral transduced stable overexpression (SW480+UCA1//GFP) and knockdown (SW620+CRISPRgUCA1) cell lines have been utilized for this study. After subjecting these cell lines (along with control) to anchorage-independent growth conditions, cell cycle, pro-survival, anti-apoptotic, stemness, and glucose metabolism factors will be analyzed through RT-PCR, Digital Droplet PCR (ddPCR), western blot, and FACS analyses. Utilizing the same model, we will examine lncRNA UCA1 linked anoikis resistance specific phosphorylation profiles of kinases, their protein substrates using the Proteome Profiler Phospho-Human Phospho-Kinase Array.

Citation Format: Sophia Leslie, Kyle D. Doxtater, Samantha Lopez, Kristopher Ezell, Adithya Anilkumar, Amayrani Sanchez, Bilal Hafeez, Tamer Oraby, Meena Jaggi, Timothy Loy, Subhash Chauhan, Manish K. Tripathi. Signaling pathways modulated by lncRNA UCA1 during anchorage-independent growth in colorectal cancer [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 1291.

COVID-19 Vaccination Drive in a Low-Volume Primary Care Clinic: Challenges & Lessons Learned in Using Homegrown Self-Scheduling Web-Based Mobile Platforms

Background: The whole of humanity has suffered dire consequences related to the novel coronavirus disease 2019 (COVID-19). Vaccination of the world base population is considered the most promising and challenging approach to achieving herd immunity. As healthcare organizations took on the extensive task of vaccinating the entire U.S. population, digital health companies expanded their automated health platforms in order to help ease the administrative burdens of mass inoculation. Although some software companies offer free applications to large organizations, there are prohibitive costs for small clinics such as the Good Health Associates Clinic (GHAC) for integrating and implementing new self-scheduling software into our e-Clinical Works (ECW) Electronic Health Record (EHR). These cost burdens resulted in a search that extended beyond existing technology, and in investing in new solutions to make it easier, more efficient, more cost-effective, and more scalable. Objective: In comparison to commercial entities, primary care clinics (PCCs) have the advantage of engaging the population for vaccination through personalized continuity of clinical care due to good rapport between their patients and the PCC team. In order to support the overall national campaign to prevent COVID-19 infections and restore public health, the GHAC wanted to make COVID-19 vaccination accessible to its patients and to the communities it serves. We aimed to achieve a coordinated COVID-19 vaccination drive in our community through our small primary care clinic by developing and using an easily implementable, cost-effective self-registration and scheduling web-based mobile platform, using the principle of “C.D.S. Five Rights”. Results: Overall, the Moderna vaccination drive using our developed self-registration and scheduling web portal and SMS messaging mobile platform improved vaccination uptake (51%) compared to overall vaccination uptake in our town, county (36%), and state (39%) during April–July 2021. Conclusions: Based on our experience during this COVID-19 vaccination drive, we conclude that PCCs have significant leverage as “invaluable warriors”, along with government and media education available, to engage patients for vaccination uptake; this leads to national preventive health spread in our population, and reduces expenses related to acute illness and hospitalization. In terms of cost-effectiveness, small PCCs are worthy of government-sponsored funding and incentives, including mandating EHR vendors to provide free (or minimal fee) software for patient self-registration and scheduling, in order to improve vaccination drive access. Hence, improved access to personalized informative continuity of clinical care in the PCC setting is a “critical link” in accelerating similar cost-effective campaigns in patient vaccine uptake.

Abstract 992: MUC13 enhances colorectal cancer metastasis through molecular interaction with YAP1 transcription factor

Colorectal cancer (CRC) is the second leading cause of cancer-related deaths in the United States. About 90% of all cancer-related deaths are due to the development of metastatic sites in the body. 40-50% of colorectal cancer patients develop metastasis at some point during their fight with the disease. Understanding the mechanism of metastasis in colorectal cancer is vital. Metastasis is a multistep process; anchorage-independent survival after intravasation of cells from the primary tumor site is a crucial step. In our lab, we have previously demonstrated that MUC13 plays an essential role in the CRC progression by modulating anti-apoptotic pathways and survival proteins expression. Under anchorage-independent growth conditions, we have identified that MUC13, in correspondence with YAP1, is the key upregulated protein and is responsible for increased survival. Isogenic CRC cell lines SW480 (non-metastatic) and SW620 (metastatic) on low adherence growth conditions are applied in these studies. In addition, lentiviral transduced stable overexpression and knockdown cell lines were generated for MUC13 and YAP1 mechanistic studies. The overexpression of MUC13 in non-metastatic SW480 cells (low MUC13 expressing) increased anchorage-independent survival and enhanced tumorigenesis compared to SW480+Vector cells, contrary results were found upon MUC13 knockdown in SW620 cells (high MUC13 expressing). In vitro results were recapitulated in the in vivo mouse model system and human CRC tissues. In Proximity Ligation Assays (PLA), we found an increased nuclear localization of the survival complex YAP1/β-catenin in MUC13 overexpressing cells. In contrast, MUC13 knockdown resulted to the lower aboudance of survival complex in the nucleus. Immunoprecipitation validates the protein-protein interaction between MUC13 and YAP1. YAP1 knockdown in MUC13 overexpressing cells showed a decrease in survival, indicating the necessary functional complex formation between MUC13 and YAP1. MUC13 and YAP1 expression in human CRC tissue were highest at Stage II. However, YAP1 expression increased when MUC13 was observed in the nucleus. This supports the notion that MUC13 is critical in enhancing CRC metastasis through molecular interaction with YAP1. For the first time, this study demonstrates complex formation between MUC13 and YAP1 and defines their role in CRC progression and metastasis.

Citation Format: Kyle Doxtater, Manish K. Tripathi, Radhika Sekhri, Sudhir Kotnala, Bilal Hafeez, Sheema Khan, Nadeem Zafar, Murali Yallapu, Meena Jaggi, Subhash Chauhan. MUC13 enhances colorectal cancer metastasis through molecular interaction with YAP1 transcription factor [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 992.

Steviol Represses Glucose Metabolism and Translation Initiation in Pancreatic Cancer Cells

Pancreatic cancer has the worst prognosis and lowest survival rate among all cancers. Pancreatic cancer cells are highly metabolically active and typically reprogrammed for aberrant glucose metabolism; thus they respond poorly to therapeutic modalities. It is highly imperative to understand mechanisms that are responsible for high glucose metabolism and identify natural/synthetic agents that can repress glucose metabolic machinery in pancreatic cancer cells, to improve the therapeutic outcomes/management of pancreatic cancer patients. We have identified a glycoside, steviol that effectively represses glucose consumption in pancreatic cancer cells via the inhibition of the translation initiation machinery of the molecular components. Herein, we report that steviol effectively inhibits the glucose uptake and lactate production in pancreatic cancer cells (AsPC1 and HPAF-II). The growth, colonization, and invasion characteristics of pancreatic cancer cells were also determined by in vitro functional assay. Steviol treatment also inhibited the tumorigenic and metastatic potential of human pancreatic cancer cells by inducing apoptosis and cell cycle arrest in the G1/M phase. The metabolic shift by steviol was mediated through the repression of the phosphorylation of mTOR and translation initiation proteins (4E-BP1, eIF4e, eIF4B, and eIF4G). Overall, the results of this study suggest that steviol can effectively suppress the glucose metabolism and translation initiation in pancreatic cancer cells to mitigate their aggressiveness. This study might help in the design of newer combination therapeutic strategies for pancreatic cancer treatment.

A Case Report of a Patient on Therapeutic Warfarin Who Died of COVID-19 Infection with a Sudden Rise in D-Dimer

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has disrupted social and economic life globally. The global pandemic COVID-19 caused by this novel SARS-CoV-2 shows variable clinical manifestations, complicated further by cytokine storm, co-infections, and coagulopathy, leading to severe cases and death. Thrombotic complications arise due to complex and unique interplay between coronaviruses and host cells, inflammatory response, and the coagulation system. Heparin and derivatives are World Health Organization (WHO) recommended anticoagulants for moderate and severe Corona Virus Disease 19 (COVID-19), that can also inhibit viral adhesion to the cell membrane by interfering with heparan sulfate-dependent binding to angiotensin-converting enzyme 2 (ACE2) receptor. Heparin also possesses anti-inflammatory, immunomodulatory, antiviral, and anti-complement activity, which offers a benefit in limiting viral and microbial infectivity and anticoagulation from the immune-thrombosis system. Here we present a case study of the pathophysiology of unexpected COVID-19 coagulopathy of an obese African American patient. While being on therapeutic warfarin since admission, he had a dismal outcome due to cardio-pulmonary arrest after the sudden rise in D-dimer value from 1.1 to >20. This indicates that for such patients on chronic warfarin anticoagulation with “moderate COVID 19 syndromes”, warfarin anticoagulation may not be suitable compared to heparin and its derivatives. Further research should be done to understand the beneficial role of heparin and its derivatives compared to warfarin for COVID-19 inflicted patients.

Stress and Molecular Drivers for Cancer Progression: A Longstanding Hypothesis

Stress management is becoming very important part of cancer patient care. Chronic stressors lead to boost tumorigenesis and promote cancer development, recurrence, and drug resistant leading to poor health outcomes. The Hypothalamic-Pituitary-Adrenal (HPA) axis, which is activated by stress, also regulates Hypothalamic-Pituitary-Thyroid (HPT) axis. Stress related changes in immune function and inflammatory response also leads to reduced immune surveillance resulting in tumorigenesis. This article explores the hormonal axis impacted by stress and how chronic stress can lead to poor outcome of a cancer patient.

Molecular Modelling a Key Method for Potential Therapeutic Drug Discovery

The well-defined and characterized 3D crystal structure of a protein is important to explore the topological and physiological features of the protein. The distinguished topography of a protein helps medical chemists design drugs on the basis of the pharmacophoric features of the protein. Structure-based drug discovery, specifically for pathological proteins that cause a higher risk of disease, takes advantage of this fact. Current tools for studying drug-protein interactions include physical, chromatographic, and electrophoretic methods. These techniques can be separated into either non-spectroscopic (equilibrium dialysis, ultrafiltration, ultracentrifugation, etc.) or spectroscopic (Fluorescence spectroscopy, NMR, X-ray diffraction, etc.) methods. These methods, however, can be time-consuming and expensive. On the other hand, in silico methods of analyzing protein-drug interactions, such as docking, molecular simulations, and High-Throughput Virtual Screenings (HTVS), are heavily underutilized by core drug discovery laboratories. These kinds of approaches have a great potential for the mass screening of potential small drugs molecules. Studying protein-drug interactions is of particular importance for understanding how the structural conformation of protein elements affect overall ligand binding affinity. By taking a bioinformatics approach to analyzing drug-protein interactions, the speed with which we identify potential drugs for genetic targets can be greatly increased.

Clinical Implications of Exosomes: Targeted Drug Delivery for Cancer Treatment

Exosomes are nanoscale vesicles generated by cells for intercellular communication. Due to their composition, significant research has been conducted to transform these particles into specific delivery systems for various disease states. In this review, we discuss the common isolation and loading methods of exosomes, some of the major roles of exosomes in the tumor microenvironment, as well as discuss recent applications of exosomes as drug delivery vessels and the resulting clinical implications.

Abstract 3142: Stress regulated role of lncRNA Malat1 in colorectal cancer progression and metastasis

Background: Colorectal carcinoma (CRC) is the second leading cause of cancer related deaths in the United States. The five-year survival rate of patients diagnosed with distant stages declines to 14%, which is of concern when compared to 90% for localized-stage and 71% for regional stage disease. This necessitates the need for early diagnostic biomarkers, to minimize poor drug response/resistance, recurrence, metastasis and mortality. Disproportionate biochemical stressors increase the risk of developing CRC and its progression by influencing molecular drivers within the coding and noncoding parts of the genome. Thus, understanding the biological mechanism of these stress factors on the molecular drivers of this disease can provide pivotal information pertinent to CRC development and progression. Recently, our laboratory has identified a novel long noncoding RNA (lncRNA) namely, Metastasis Associated Lung Adenocarcinoma Transcript 1 (MALAT1), which is highly over-expressed in CRC and is involved in its pathogenesis and is regulated by transcription factor Nuclear Factor of Activated T cell 1 (NFATc1).

Methods: Archived human CRC tissues were stained using a recently standardized Z-probe technology. TCGA database of ~600 CRC patients was also analyzed using the bioinformatic approach. CRC cell lines were profiled for MALAT1 expression using RT-PCR. Lentiviral constructs were used to generate stable lncRNA MALAT1 expressing cell lines. CRISPR/Cas9 constructs were used to knockdown lncRNA MALAT1 and NFATc1. Mouse model was used to verify the stress induced expression of MALAT1 and NFATc1. ReCLP (Reversible Cross-Linked Precipitation) and iRAP (invitro RNA Antisense Proteomics) studies are in progress to identify the associated proteins and complexes.

Results: RNAScope analysis showed MALAT1 to be highly over-expressed in human CRC tissues. MALAT1 expression increased with stage and negatively correlated with the tumor size. TCGA database analysis confirmed our findings. Multiple NFATc1 binding site were identified by ChIPseq database. Overexpression of transcription factor NFATc1 upregulated lncRNA MALAT1 expression. CRISPR/Cas9 based knockdown of NFATc1 downregulated NFATC1 and lncRNA MALAT1, but vice versa was not true, indicating NFATc1 to be upstream of lncRNA MALAT1. Also, expression of MALAT1, NFATc1 and IL-6 were highly upregulated by biochemical stressor cortisol in mouse colonic tissues. Further studies are in progress for direct association of NFATc1 on MALAT1 promoter and mechanism by which the stress factor regulate NFATc1 expression and hence lncRNA MALAT1 expression.

Conclusion: This study helps to understand influence of biochemical stress factors on long noncoding RNA MALAT1 and transcription factor NFATc1 etiology. Early diagnosis of these molecular markers will help in designing novel preventive/therapeutic strategies to reduce CRC progression, metastasis and hence mortality.

Citation Format: Kyle Doxtater, Chidi Zacheaus, Radhika Sekhri, Utkarsh K. Mishra, Zachary E. Stiles, Nitish Mishra, Chittibabu Guda, Nadeem Zafar, Mahul Amin, Pradeep Shukla, Murali M. Yallapu, Meena Jaggi, Subhash C. Chauhan, Manish K. Tripathi. Stress regulated role of lncRNA Malat1 in colorectal cancer progression and metastasis [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 3142.

Cross-Linked Polyphenol-Based Drug Nano-Self-Assemblies Engineered to Blockade Prostate Cancer Senescence

Cellular senescence is one of the prevailing issues in cancer therapeutics that promotes cancer relapse, chemoresistance, and recurrence. Patients undergoing persistent chemotherapy often develop drug-induced senescence. Docetaxel, an FDA-approved treatment for prostate cancer, is known to induce cellular senescence which often limits the overall survival of patients. Strategic therapies that counter the cellular and drug-induced senescence are an unmet clinical need. Towards this an effort was made to develop a novel therapeutic strategy that targets and removes senescent cells from the tumors, we developed a nanoformulation of tannic acid-docetaxel self-assemblies (DSAs). The construction of DSAs was confirmed through particle size measurements, spectroscopy, thermal, and biocompatibility studies. This formulation exhibited enhanced in vitro therapeutic activity in various biological functional assays with respect to native docetaxel treatments. Microarray and immunoblot analysis results demonstrated that DSAs exposure selectively deregulated senescence associated TGFβR1/FOXO1/p21 signaling. Decrease in β-galactosidase staining further suggested reversion of drug-induced senescence after DSAs exposure. Additionally, DSAs induced profound cell death by activation of apoptotic signaling through bypassing senescence. Furthermore, in vivo and ex vivo imaging analysis demonstrated the tumor targeting behavior of DSAs in mice bearing PC-3 xenograft tumors. The antisenescence and anticancer activity of DSAs was further shown in vivo by inhibiting TGFβR1 proteins and regressing tumor growth through apoptotic induction in the PC-3 xenograft mouse model. Overall, DSAs exhibited such advanced features due to a natural compound in the formulation as a matrix/binder for docetaxel. Overall, DSAs showed superior tumor targeting and improved cellular internalization, promoting docetaxel efficacy. These findings may have great implications in prostate cancer therapy.

Abstract 1871: Tannic acid: A natural anticancer agent for non-small cell lung cancer

Background

Lung cancer is the leading cause of cancer deaths across globe. Statistically, 70-80% of lung cancer cases fall under non-small cells lung cancer (NSCLC) category. Recently, usage of natural compounds (e.g. EGCG, curcumin, resveratrol, apigenin, etc.,) for cancer therapy has gained lots of attention. However, poor dissolution profiles of these natural compounds lead to unfavorable pharmacological doses and administration. For this purpose, we have candidate, a water-soluble natural polyphenol, Tannic acid (TA, C76H52O46), which, a natural polyphenol that is richly found in plants such as green tea. This molecule exhibits anti-oxidant and anti-proliferative activities, which is being used as an alternative therapeutic option in cancer therapy. However, role of TA in NSCLC was not examined. Therefore, the aim of present study is to assess the molecular effects of TA in NSCLC cells.

Methods

For this study, two NSCLC cell lines (A549 and H1299) and one normal lung cell line (BEAS-2B) were used. We investigated the anti-proliferative effects of TA on NSCLC cells using 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide) tetrazolium (MTT), and colony formation assays. The anti-invasiveness and anti-migratory potential of TA was evaluated through Matrigel and Boyden chamber studies, respectively. Cell cycle and apoptotic effects of TA was evaluated through flow cytometry and western blot studies. The quantification of secreted VEGF was assessed by ELISA. Also, for affirmation results of gene expression profiles we performed q-PCR studies.

Results

Cell proliferation study demonstrated a dose dependent anti-cancer effects of TA on NSCLC cells. However, TA had no significant toxicity effects on human bronchial epithelial cells. Similarly, colony formation results exhibited dose dependence reduction in response to escalated dose of TA exposure. Both the invasion and migration results confirm its anti-metastatic role. Extracellular VEGF quantification showed lower VEGF secretion with TA treatments compared to the control cells. The cell cycle analysis evidently showed TA efficiently induced G1 phase cell arrest in NSCLC cells which was further confirmed through western blotting studies of relevant proteins (Cyclin D1, P53, p21, p18, BAX, BCL-2). We also achieved to show the decreased expression of VEGFR2, p-AKT, and cleaved caspase 7 indicating TA induces apoptosis.

Conclusion

Overall, these results demonstrate illustrate anti-cancer activity of TA by targeting the VEGF related pathways in NSCLC. This approach can lead to an alternative therapeutic strategy for lung cancer, with ideal PK/PD profiles.

Citation Format: Elham Hatami, Prashanth K.B. Nagesh, Pallabita Chowdhury, Advit Bhaskar Shetty, Manish K. Tripathi, Subhash Chauhan, Meena Jaggi, Murali Yallapu. Tannic acid: A natural anticancer agent for non-small cell lung cancer [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 1871.

Tannic acid-inspired paclitaxel nanoparticles for enhanced anticancer effects in breast cancer cells

Paclitaxel (PTX) is a gold standard chemotherapeutic agent for breast, ovarian, pancreatic and non-small cell lung carcinoma. However, in clinical use PTX can have adverse side effects or inadequate pharmacodynamic parameters, limiting its use. Nanotechnology is often employed to reduce the therapeutic dosage required for effective therapy, while also minimizing the systemic side effects of chemotherapy drugs. However, there is no nanoformulation of paclitaxel with chemosensitization motifs built in. With this objective, we screened eleven pharmaceutical excipients to develop an alternative paclitaxel nanoformulation using a self-assembly method. Based on the screening results, we observed tannic acid possesses unique properties to produce a paclitaxel nanoparticle formulation, i.e., tannic acid-paclitaxel nanoparticles. This stable TAP nanoformulation, referred to as TAP nanoparticles (TAP NPs), showed a spherical shape of ~ 102 nm and negative zeta potential of ~ -8.85. The presence of PTX in TAP NPs was confirmed by Fourier Transform Infrared (FTIR) spectra, thermogravimetric analyzer (TGA), and X-ray diffraction (XRD). Encapsulation efficiency of PTX in TAP NPs was determined to be ≥96%. Intracellular drug uptake of plain drug PTX on breast cancer cells (MDA-MB-231) shows more or less constant drug levels in 2 to 6 h, suggesting drug efflux by the P-gp transporters, over TAP NPs, in which PTX uptake was more than 95.52 ± 11.01% in 6 h, as analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Various biological assays such as proliferation, clonogenic formation, invasion, and migration confirm superior anticancer effects of TAP NPs over plain PTX at all tested concentrations. P-gp expression, beta-tubulin stabilization, Western blot, and microarray analysis further confirm the improved therapeutic potential of TAP NPs. These results suggest that the TAP nanoformulation provides an important reference for developing a therapeutic nanoformulation affording pronounced, enhanced effects in breast cancer therapy.

Design and development of novel p-aminobenzoic acid derivatives as potential cholinesterase inhibitors for the treatment of Alzheimer's disease

Based on the quantitative structure-activity relationship (QSAR), some novel p-aminobenzoic acid derivatives as promising cholinesterase enzyme inhibitors were designed, synthesized, characterized and evaluated to enhance learning and memory. The in vitro enzyme kinetic study of the synthesized compounds revealed the type of inhibition on the respective acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes. The in vivo studies of the synthesized compounds exhibited significant reversal of cognitive deficits in the animal models of amnesia as compared to standard drug donepezil. Further, the ex vivo studies in the specific brain regions like the hippocampus, hypothalamus, and prefrontal cortex regions also exhibited AChE inhibition comparable to standard donepezil. The in silico molecular docking and dynamics simulations studies of the most potent compound 22 revealed the consensual interactions at the active site pocket of the AChE.

Z Probe, An Efficient Tool for Characterizing Long Non-Coding RNA in FFPE Tissues

Formalin-fixed paraffin embedded (FFPE) tissues are a valuable resource for biomarker discovery in order to understand the etiology of different cancers and many other diseases. Proteins are the biomarkers of interest with respect to FFPE tissues as RNA degradation is the major challenge in these tissue samples. Recently, non-protein coding transcripts, long non-coding RNAs (lncRNAs), have gained significant attention due to their important biological actions and potential involvement in cancer. RNA sequencing (RNA-seq) or quantitative reverse transcription-polymerase chain reaction (qRT-PCR) are the only validated methods to evaluate and study lncRNA expression and neither of them provides visual representation as immunohistochemistry (IHC) provides for proteins. We have standardized and are reporting a sensitive Z probe based in situ hybridization method to visually identify and quantify lncRNA in FFPE tissues. This assay is highly sensitive and identifies transcripts visible within different cell types and tumors. We have detected a scarcely expressed tumor suppressor lncRNA NRON (non-coding repressor of nuclear factor of activated T-cells (NFAT)), a moderately expressed oncogenic lncRNA UCA1 (urothelial cancer associated 1), and a highly studied and expressed lncRNA MALAT1 (metastasis associated lung adenocarcinoma transcript 1) in different cancers. High MALAT1 staining was found in colorectal, breast and pancreatic cancer. Additionally, we have observed an increase in MALAT1 expression in different stages of colorectal cancer.

Abstract 5178: MUC13 is a novel molecular signature, for early detection and metastatic colorectal cancer

Objective: Colorectal cancer (CRC) is a leading cause of cancer mortality affecting over a million people every year. Biological markers for early detection and distant metastatic disease in patients with CRC are not well defined. We have identified transmembrane mucin MUC13, which is expressed in normal colon mucosa to be highly expressed in colorectal cancer, but the underlying pathways and the signaling mechanisms involved in CRC pathogenesis are not known. Our studies suggest MUC13 correlation with demographic and clinicopathologic characteristics.

Materials and Methods: Retrospective institutional tumor registry was reviewed to identify patients with resected colon adenocarcinoma. Archived FFPE tissue blocks were reviewed by an experienced pathologist. Selected representative tissue blocks were serially sectioned at 4 µm. IHC staining was performed using an in-house MAb for MUC13. Slides were digitally scanned and analyzed qualitatively as well as quantitatively using a modified H-score based on the intensity of expression and percentage of stained cells. MUC13 was correlated with disease stage, aggressiveness and inflammatory markers, indicating poor prognosis in CRC patients. MUC13 splice variants were probed using novel designed probes. MUC13 SNPs were identified using unbiased approach by analyzing dpGAP database.

Results: 196 tissues, of which 56.1% were female, 52% were white, and the median age at resection was 70. 38 (19.4%) were stage I, 64 (32.7%) stage II, 84 (42.9%) stage III, and 10 (5.1%) stage IV. 100% of colon adenocarcinoma tissues stained positively for MUC13, including definitive tumor epithelial staining, little-to-no background stromal staining, and mild staining of adjacent normal colon mucosa. Typical colon adenocarcinoma cells exhibited strong apical membranous staining with varying degrees of cytoplasmic staining. Advanced stage tumors were noted to more frequently exhibit basolateral and/or circumferential membranous staining compared to early stage tumors which more frequently displayed apical membrane staining alone. Five MUC13 transcript variants were identified by database analysis. Two of the protein coding MUC13 variants (long and short) showed differential expression in aggressive cell lines and patient tissues. Cyclic turnover between the short and long isoforms were observed during Anoikis resistance, cortisol, alcohol and BAP treatments. SNPs have been associated with increased risk of cancer incidence or fatality. Relevant MUC13 SNPs have been identified through systematic analysis of patient databases (dpGAP database). Verification and correlation of identified SNPs with patient disease stage and prognosis will also be presented.

Conclusion: This is the first study to correlate MUC13 expression with disease outcome. Alternative transcripts and single nucleotide polymorphisms gave genetic insight of the role of MUC13 in CRC pathogenesis.

Citation Format: Manish K. Tripathi, Chidi Zacheaus, Kyle Doxtater, Zachary Stiles, Fatemeh Keramatnia, Nadeem Zafar, Mahul Amin, Meena Jaggi, Subhash Chauhan. MUC13 is a novel molecular signature, for early detection and metastatic colorectal cancer [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 5178.

Protein kinase D1 regulates subcellular localisation and metastatic function of metastasis-associated protein 1

BACKGROUND

Cancer progression and metastasis is profoundly influenced by protein kinase D1 (PKD1) and metastasis-associated protein 1 (MTA1) in addition to other pathways. However, the nature of regulatory relationship between the PKD1 and MTA1, and its resulting impact on cancer metastasis remains unknown. Here we present evidence to establish that PKD1 is an upstream regulatory kinase of MTA1.

METHODS

Protein and mRNA expression of MTA1 in PKD1-overexpressing cells were determined using western blotting and reverse-transcription quantitative real-time PCR. Immunoprecipitation and proximity ligation assay (PLA) were used to determine the interaction between PKD1 and MTA1. PKD1-mediated nucleo-cytoplasmic export and polyubiquitin-dependent proteosomal degradation was determined using immunostaining. The correlation between PKD1 and MTA1 was determined using intra-tibial, subcutaneous xenograft, PTEN-knockout (PTEN-KO) and transgenic adenocarcinoma of mouse prostate (TRAMP) mouse models, as well as human cancer tissues.

RESULTS

We found that MTA1 is a PKD1-interacting substrate, and that PKD1 phosphorylates MTA1, supports its nucleus-to-cytoplasmic redistribution and utilises its N-terminal and kinase domains to effectively inhibit the levels of MTA1 via polyubiquitin-dependent proteosomal degradation. PKD1-mediated downregulation of MTA1 was accompanied by a significant suppression of prostate cancer progression and metastasis in physiologically relevant spontaneous tumour models. Accordingly, progression of human prostate tumours to increased invasiveness was also accompanied by decreased and increased levels of PKD1 and MTA1, respectively.

CONCLUSIONS

Overall, this study, for the first time, establishes that PKD1 is an upstream regulatory kinase of MTA1 status and its associated metastatic activity, and that the PKD1-MTA1 axis could be targeted for anti-cancer strategies.

Ormeloxifene Suppresses Prostate Tumor Growth and Metastatic Phenotypes via Inhibition of Oncogenic β-catenin Signaling and EMT Progression

Ormeloxifene is a clinically approved selective estrogen receptor modulator, which has also shown excellent anticancer activity, thus it can be an ideal repurposing pharmacophore. Herein, we report therapeutic effects of ormeloxifene on prostate cancer and elucidate a novel molecular mechanism of its anticancer activity. Ormeloxifene treatment inhibited epithelial-to-mesenchymal transition (EMT) process as evident by repression of N-cadherin, Slug, Snail, vimentin, MMPs (MMP2 and MMP3), β-catenin/TCF-4 transcriptional activity, and induced the expression of pGSK3β. In molecular docking analysis, ormeloxifene showed proficient docking with β-catenin and GSK3β. In addition, ormeloxifene induced apoptosis, inhibited growth and metastatic potential of prostate cancer cells and arrested cell cycle in G₀-G₁ phase via modulation of cell-cycle regulatory proteins (inhibition of Mcl-1, cyclin D1, and CDK4 and induction of p21 and p27). In functional assays, ormeloxifene remarkably reduced tumorigenic, migratory, and invasive potential of prostate cancer cells. In addition, ormeloxifene treatment significantly (P < 0.01) regressed the prostate tumor growth in the xenograft mouse model while administered through intraperitoneal route (250 μg/mouse, three times a week). These molecular effects of ormeloxifene were also observed in excised tumor tissues as shown by immunohistochemistry analysis. Our results, for the first time, demonstrate repurposing potential of ormeloxifene as an anticancer drug for the treatment of advanced stage metastatic prostate cancer through a novel molecular mechanism involving β-catenin and EMT pathway. Mol Cancer Ther; 16(10); 2267-80. ©2017 AACR.

In-vitro fermentation characteristics and methane reduction potential of mustard cake (Brassica juncea L.)

Aim:

To assess the effect of mustard cake (Brassica juncea L.) levels in concentrate mixtures and in composite feed mixtures (CFMs) on in-vitro fermentation characteristics and methane production.

Materials and Methods:

Five concentrate mixtures were prepared with containing 30% oil cake, where linseed cake was replaced by mustard cake at the rate of 0%, 7.5%, 15.0%, 22.5%, and 30% in concentrate mixture. Mustard cake contained glucosinolate 72.58 µmol/g oil free dry matter (DM) and contents in diet were 0, 5.4, 10.9, 16.3, and 21.8 µmol/g of concentrate mixture, respectively. Concentrate mixture containing 15.0% mustard cake was found to produced minimum methane which was then used for the preparation of CFM containing 0%, 25%, 50%, and 75% levels with gram straw.

Result:

Increased levels of mustard cake in concentrate mixtures had a linear decrease (p<0.05) in the total gas production, and the 15% inclusion showed lowest methane concentration (quadratic, p<0.01). The degradability of DM and organic matter (OM) of concentrate mixtures did not change, however, pH and NH₃-N concentrations of the fermentation medium showed linear (p<0.05) reductions with increased mustard cake levels. Increased levels of 15% mustard cake containing concentrate mixture in CFMs exhibited a trend (p=0.052) of increased gas production, whereas methane concentration in total gas, methane produced and degradability of DM and OM were also displayed a linear increase (p<0.05). However, the pH, NH₃-N, and total volatile fatty acid levels decreased linearly (p<0.05) with increased levels of concentrate in CFMs.

Conclusion:

Reduction in methane production was evidenced with the inclusion of mustard cake in concentrate mixture at 15% level, and the CFMs with 25% concentrate, which contained 15% mustard cake, exhibited an improved fermentation and reduced methane production.

Abstract 2884: Role of Kaiso in intestinal tumorigenesis

p120-catenin is a master regulator of classical cadherin stability and essential for epithelial homeostasis. p120 physically interacts with transcription factor Kaiso (ZBTB33) suggesting a direct or indirect role in transcription, but its precise function with respect to Kaiso is largely unknown. Kaiso belongs to the ZBTB family of transcription factors, most of which have important roles in development and/or cancer. Interestingly, Kaiso is strongly expressed in the intestinal crypt and abruptly downregulated as the cells move up onto the villus and terminally differentiate. Kaiso is constitutively upregulated in nascent adenomas initiated by loss of the tumor suppressor APC, suggesting a link between canonical Wnt signaling, Kaiso upregulation and intestinal tumorigenesis. Here, using ChipSeq and proteomics we describe several candidate Kaiso interactions with a group of proteins that include the tumor suppressor BRCA1, CHD2 (a chromatin remodifier) and the Ets1 oncoprotein, along with preliminary evidence for functional significance relevant to intestinal tumorigenesis.

Citation Format: Manish K. Tripathi, Albert B. Reynolds. Role of Kaiso in intestinal tumorigenesis. [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 2884.

Identification and structure elucidation of antimicrobial compounds from Lyngbya aestuarii and Aphanothece bullosa

Cyanobacteria are known to produce array of compounds. In an earlier report, we reported antibacterial and antifungal activities in methanolic crude extracts of laboratory grown Lyngbya aestuarii and Aphanothece bullosa isolated from Chilka Lake and local paddy field respectively. In this report the same methanolic crude extracts were subjected to TLC purification twice by altering the solvents and UV&mdash;illuminated bands bioassayed. Such UV illuminated potent bands obtained after 2nd TLC were subjected to spectroscopic analysis (UV, IR, 1H NMR and LCMS/MS). We have screened malyngolide and dragonamide C from L. aestuarii and a diterpenoid and majusculoic acid from A. bullosa. Dragonamide C and malyngolide were found to be antifungal while majusculoic acid and a diterpenoid as antibacterial. As far as our knowledge goes, this is the first ever report where fresh water A. bullosa was found to be a source of diterpenoid and majusculoic acid. Likewise, L. aestuarii was also established as a source of malyngolide and dragonamide C. This again indicated that cyanobacteria are inherently endowed with the capacity to produce metabolites according to niche and species specific manner emphasising fresh water cyanobacterial strain are as important as marine one.

Nuclear factor of activated T-cell activity is associated with metastatic capacity in colon cancer

Metastatic recurrence is the leading cause of cancer-related deaths in patients with colorectal carcinoma. To capture the molecular underpinnings for metastasis and tumor progression, we performed integrative network analysis on 11 independent human colorectal cancer gene expression datasets and applied expression data from an immunocompetent mouse model of metastasis as an additional filter for this biologic process. In silico analysis of one metastasis-related coexpression module predicted nuclear factor of activated T-cell (NFAT) transcription factors as potential regulators for the module. Cells selected for invasiveness and metastatic capability expressed higher levels of NFATc1 as compared with poorly metastatic and less invasive parental cells. We found that inhibition of NFATc1 in human and mouse colon cancer cells resulted in decreased invasiveness in culture and downregulation of metastasis-related network genes. Overexpression of NFATc1 significantly increased the metastatic potential of colon cancer cells, whereas inhibition of NFATc1 reduced metastasis growth in an immunocompetent mouse model. Finally, we found that an 8-gene signature comprising genes upregulated by NFATc1 significantly correlated with worse clinical outcomes in stage II and III colorectal cancer patients. Thus, NFATc1 regulates colon cancer cell behavior and its transcriptional targets constitute a novel, biologically anchored gene expression signature for the identification of colon cancers with high risk of metastatic recurrence.

Role of proinflammatory cytokines (interferon gamma) and anti-inflammatory cytokine (interleukin-10) gene polymorphisms in chronic hepatitis B infection: an Indian scenario

Immune-mediated mechanisms have been found to play an important role in the progression of hepatitis B virus (HBV) infection. The outcomes of infection do not appear to be determined by viral strains. Instead, allelic variants in human genome are likely to affect the disease progression. Allelic variation of proinflammatory cytokines such as interferon gamma (IFN-γ) participates in the elimination of HBV, and interleukin-10 (IL-10) helps in inhibition of Th1 effector mechanisms for host defense. The aim of this study was to determine the influence of host genetic factors in chronic HBV infection and gene promoter polymorphism or single-nucleotide polymorphism analysis of IFN-γ+874 and IL-10 (-1082, -592, and -819) on disease progression and persistence. A total of 232 patients along with 76 healthy controls were included. Allele-specific primers for IFN-γ and restriction fragment length polymorphism for IL-10 were used. The study indicated that low IFN-γ expression probably impairs host immune response to HBV, rendering these subjects more prone to HBV infection. No significant differences were detected between the 2 groups in the distributions of IL-10 genotype at the -1082, -819, and -592 positions. Odds ratio indicated that heterozygosity of genotypes -819 CT and -592 AC was more strongly associated with liver chronicity. Significantly, AA homozygous genotype was dominant in chronic hepatitis B cases in IFN-γ+874 and IL-10 (-1082 and -592) and is associated with increased risk of persistent infection.

Abstract B101: NFAT regulates a gene expression program associated with invasiveness and poor prognosis in colorectal cancer

Colorectal cancer is the second leading cause of cancer-related death in the United States. In order to understand the regulatory mechanisms underlying poor prognosis in colorectal cancer, we analyzed fourteen human colorectal cancer microarray data sets and identified co-expressed modules using network analysis. We next filtered these modules using gene expression data from a mouse model of metastatic colon cancer, narrowing down to a candidate metastasis-related module, and identified NFAT as its potential transcriptional regulator. The NFAT family and their identified targets were found to be upregulated in human colorectal cancer patients. Analysis of NFAT family members expression in mouse and human microarray datasets, revealed NFATc1 to be differentially expressed between metastatic and non-metastatic, and between disease progression and no disease progression, respectively. We found that high NFATc1 expression correlated with significantly increased invasion (p&lt;0.0001) and migration (p&lt;0.005) in mouse colon cancer cells. We show that RNAi- based knockdown of NFATc1 and functional inhibition by the calcineurin inhibitor FK506 resulted in downregulation of predicted NFAT target genes from the metastatic module and decreased cancer cell invasiveness. Finally, we showed that the expression of NFAT target genes was significantly correlated with both disease-specific and disease-free survival in Stage II and III colorectal cancer patients. Our studies suggest a role for NFATs in colon cancer cell invasion and a potential application for the NFAT driven program as a biologically anchored prognostic gene expression signature.

Citation Format: Manish K. Tripathi, Shinji Mima, Zhiao Shi, Naresh Prodduturi, Zhu Jing, Kristen K. Ciombor, Xi Chen, Natasha Deane, Robert D. Beauchamp, Bing Zhang. NFAT regulates a gene expression program associated with invasiveness and poor prognosis in colorectal cancer. [abstract]. In: Proceedings of the AACR Special Conference on Tumor Invasion and Metastasis; Jan 20-23, 2013; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2013;73(3 Suppl):Abstract nr B101.

Regulation of CXCR4-mediated invasion by DARPP-32 in gastric cancer cells

Although Dopamine and cAMP-regulated phosphoprotein, Mr 32000 (DARPP-32) is overexpressed in two-thirds of gastric cancers, its impact on molecular functions has not been fully characterized. In this study, we examined the role of DARPP-32 in gastric cancer cell invasion. Using matrigel-coated Boyden chamber invasion assay, DARPP-32-overexpressing AGS cells showed a three-fold increase in invasion relative to the vector control (P < 0.01). We also tested the transendothelial cell invasion as a measure of cell aggressiveness using the impedance-based human umbilical vein endothelial cells invasion assay and obtained similar results (P < 0.001). Western blot analysis indicated that overexpression of DARPP-32 mediated an increase in the membrane-type 1 matrix metalloproteinase (MT1-MMP) and CXCR4 protein levels. Consistent with the role of MT1-MMP in cleaving extracellular matrix proteins initiating the activation of soluble MMPs, we detected a robust increase in MMP-2 activity in DARPP-32-overexpressing cells. The knockdown of endogenous DARPP-32 in the MKN-45 cells reversed these signaling events and decreased cell invasive activity. We tested whether the invasive activity mediated by DARPP-32 might involve sustained signaling via CXCR4-dependent activation of the MT1-MMP/MMP-2 pathway. The small-molecule CXCR4 antagonist (AMD3100) and CXCR4-siRNA blocked DARPP-32-induced cell invasion. We further examined our hypothesis that DARPP-32 could interact with CXCR4 and stabilize its levels following stimulation with its ligand, CXCL12. Using reciprocal coimmunoprecipitation and immunofluorescence experiments, we found that DARPP-32 and CXCR4 coexist in the same protein complex. DARPP-32 prolonged the CXCR4 protein half-life and reduced ubiquitination of the CXCR4 protein, following treatment with its ligand, CXCL12. In conclusion, these findings show a novel mechanism by which DARPP-32 promotes cell invasion by regulating CXCR4-mediated activation of the MT1-MMP/MMP-2 pathway.

Abstract 499: NFATc1 is a novel invasion promoter in colorectal cancer

Colorectal carcinoma is the third leading cause of cancer-related death in the United States. In order to understand the mechanism/signaling pathways responsible for invasion, migration and metastasis in colorectal cancer, our lab successfully modeled human cancer invasion/metastasis using mouse colon cancer cells. We have developed an integrative and comparative computational approach to reveal transcriptional regulatory mechanisms underlying colon cancer progression. Applying this approach to fourteen human colorectal cancer (CRC) microarray data sets and to one microarray dataset from an immunocompetent mouse model of metastasis, we identified known and novel transcriptional regulators in CRC. Among these transcriptional regulators, the Nuclear Factor of Activated T cells (NFAT) family of transcription factors play a central role in inducible gene transcription in various signaling pathways including regulation of cell differentiation, development, adaption, immune system response, inflammation, adipocyte metabolism, and lipolysis, and carcinogenesis. We found that an NFAT-driven transcriptional program significantly correlates with disease-free survival in multiple CRC Stage II patients. Using quantitative real time RT-PCR, we validated high NFATc1 expression in a subgroup of stage II colorectal cancer patients and differential expression of predicted NFATc1 targets in the same patients. The tumor-associated NFATc1 co-regulated gene signature was associated with worse clinical survival outcomes in stage II colorectal cancer patients. In comparison with parental MC38 mouse colon cancer cells, NFATc1 expression is increased in MC38met cells selected for invasive and metastatic ability, RNAi-based inhibition of NFATc1 expression in the MC38met cells resulted in decreased invasiveness in a transendothelial invasion model. Our studies suggest a role for NFATc1 as a tumor promoting transcription factor that contributes to invasion in colon cancer.

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 499. doi:1538-7445.AM2012-499

Protein translocase of mitochondrial inner membrane in Trypanosoma brucei

Translocases of mitochondrial inner membrane (TIMs) are multiprotein complexes. The only Tim component so far characterized in kinetoplastid parasites such as Trypanosoma brucei is Tim17 (TbTim17), which is essential for cell survival and mitochondrial protein import. Here, we report that TbTim17 is present in a protein complex of about 1,100 kDa, which is much larger than the TIM complexes found in fungi and mammals. Depletion of TbTim17 in T. brucei impairs the mitochondrial import of cytochrome oxidase subunit IV, an N-terminal signal-containing protein. Pretreatment of isolated mitoplasts with the anti-TbTim17 antibody inhibited import of cytochrome oxidase subunit IV, indicating a direct involvement of the TbTim17 in the import process. Purification of the TbTim17-containing protein complex from the mitochondrial membrane of T. brucei by tandem affinity chromatography revealed that TbTim17 associates with seven unique as well as a few known T. brucei mitochondrial proteins. Depletion of three of these novel proteins, i.e. TbTim47, TbTim54, and TbTim62, significantly decreased mitochondrial protein import in vitro. In vivo targeting of a newly synthesized mitochondrial matrix protein, MRP2, was also inhibited due to depletion of TbTim17, TbTim54, and TbTim62. Co-precipitation analysis confirmed the interaction of TbTim54 and TbTim62 with TbTim17 in vivo. Overall, our data reveal that TbTim17, the single homolog of Tim17/22/23 family proteins, is present in a unique TIM complex consisting of novel proteins in T. brucei and is critical for mitochondrial protein import.

TFIIA and the transactivator Rap1 cooperate to commit TFIID for transcription initiation

Transcription of eukaryotic mRNA encoding genes by RNA polymerase II (Pol II) is triggered by the binding of transactivating proteins to enhancer DNA, which stimulates the recruitment of general transcription factors (GTFs; TFIIA, B, D, E, F, H) and Pol II on the cis-linked promoter leading to preinitiation complex (PIC) formation and transcription1. In TFIID-dependent activation pathways, this TATA box Binding Protein (TBP)-containing GTF is first recruited on the promoter through interaction with activators1-3 and cooperates with TFIIA to form a committed PIC4. However, neither the mechanisms by which activation signals are communicated between these factors, nor the structural organization of the activated PIC are known. Here we used cryo-electron microscopy to determine the architecture of nucleoprotein complexes composed of TFIID, TFIIA, the transcriptional activator Rap1 and yeast enhancer-promoter DNA. These structures revealed the mode of binding of Rap1 and TFIIA to TFIID, as well as a reorganization of TFIIA induced by its interaction with Rap1. We propose that this change in position increases the exposure of TBP within TFIID, consequently enhancing its ability to interact with the promoter. A large Rap1-dependent DNA loop forms between the activator binding site and the proximal promoter region, and this loop is topologically locked by a TFIIA-Rap1 protein bridge that folds over the DNA. These results highlight the role of TFIIA in transcriptional activation, define a molecular mechanism for enhancer-promoter communication and provide important new structural insights into the pathways of intramolecular communication that convey transcription activation signals through the TFIID complex.

Cell cycle-dependent regulation of the bi-directional overlapping promoter of human BRCA2/ZAR2 genes in breast cancer cells

Background

BRCA2 gene expression is tightly regulated during the cell cycle in human breast cells. The expression of BRCA2 gene is silenced at the G0/G1 phase of cell growth and is de-silenced at the S/G2 phase. While studying the activity of BRCA2 gene promoter in breast cancer cells, we discovered that this promoter has bi-directional activity and the product of the reverse activity (a ZAR1-like protein, we named ZAR2) silences the forward promoter at the G0/G1 phase of the cell. Standard techniques like cell synchronization by serum starvation, flow cytometry, N-terminal or C-terminal FLAG epitope-tagged protein expression, immunofluorescence confocal microscopy, dual luciferase assay for promoter evaluation, and chromatin immunoprecipitation assay were employed during this study.

Results

Human BRCA2 gene promoter is active in both the forward and the reverse orientations. This promoter is 8-20 fold more active in the reverse orientation than in the forward orientation when the cells are in the non-dividing stage (G0/G1). When the cells are in the dividing state (S/G₂), the forward activity of the promoter is 5-8 folds higher than the reverse activity. The reverse activity transcribes the ZAR2 mRNA with 966 nt coding sequence which codes for a 321 amino acid protein. ZAR2 has two C4 type zinc fingers at the carboxyl terminus. In the G0/G1 growth phase ZAR2 is predominantly located inside the nucleus of the breast cells, binds to the BRCA2 promoter and inhibits the expression of BRCA2. In the dividing cells, ZAR2 is trapped in the cytoplasm.

Conclusions

BRCA2 gene promoter has bi-directional activity, expressing BRCA2 and a novel C4-type zinc finger containing transcription factor ZAR2. Subcellular location of ZAR2 and its expression from the reverse promoter of the BRCA2 gene are stringently regulated in a cell cycle dependent manner. ZAR2 binds to BRCA2/ZAR2 bi-directional promoter in vivo and is responsible, at least in part, for the silencing of BRCA2 gene expression in the G0/G1 phase in human breast cells.

Mapping the initiator binding Taf2 subunit in the structure of hydrated yeast TFIID

The general transcription factor TFIID is a large multisubunit complex required for the transcription of most protein-encoding genes by RNA polymerase II. Taking advantage of a TFIID preparation partially depleted in the initiator-binding Taf2p subunit, we determined the conformational and biochemical variations of the complex by electron tomography and cryo-electron microscopy of single molecules. Image analysis revealed the extent of conformational flexibility of the complex and the selection of the most homogeneous TFIID subpopulation allowed us to determine an improved structural model at 23 Angstroms resolution. This study also identified two subpopulations of Taf2p-containing and Taf2p-depleted TFIID molecules. By comparing these two TFIID species we could infer the position of Taf2p, which was confirmed by immunolabeling using a subunit-specific antibody. Mapping the position of this crucial subunit in the vicinity of Taf1p and of TBP sheds new light on its role in promoter recognition.

Effect of different feeding regimes on pre-weaning growth rumen fermentation and its influence on post-weaning performance of lambs

Influence of pre-weaning live weight on post-weaning growth performance was assessed on thirty-nine 15-day-old Indian native lambs, randomly fed in three equal groups until 180 days of age. During pre-weaning phase lambs were maintained under feeding regimen of grazing (C-0; Control), grazing and ad lib creep mixture supplementation (C-AL) or grazing, with ad lib creep mixture and milk replacer supplementation (C-ALMR). Lambs were allowed to suckle respective dam in morning and evening till 90 days of age, and fed ad lib green leaves of Ailanthus excelsa after grazing. After weaning all lambs were maintained on grazing and ad lib finisher concentrates supplementation. Pre-weaning performance of lambs in terms of weaning weight (17.2 kg), average daily gain (ADG; 154 g) and feed conversion ratio 3.73 was higher (p < 0.01) in C-ALMR lambs but total gain and ADG were similar among three groups during post-weaning phase. However, improved pre-weaning plane of nutrition and growth rate increased (p < 0.01) finishing weight (FW) of lambs in C-AL, 33 kg and C-ALMR, 32 kg. Dry matter intake was significantly (p < 0.01) higher in C-AL and C-ALMR lambs due to combined effect of feeding. Rumen pH was lowest (p = 0.049) in C-AL lambs. Rumen ciliate protozoa population (10(4)/ml) decreased in C-ALMR lambs (4.3) but increased in C-AL lambs (50.0) more so in C-0 Lambs (19.8). Concentrate feeding of C-AL lamb improved nutrient digestibility. Lambs of C-0 group consumed more DM during post-weaning phase that improved growth performance, while nutrient digestibility was not affected by pre-weaning nutrition. Thus, pre-weaning nutrition has significant influence on FW, however influence of milk replacer feeding on lamb growth need further studies.

Growth, haematology, blood constituents and immunological status of lambs fed graded levels of animal feed grade damaged wheat as substitute of maize

The aim of this study was to explore possibilities of utilization of animal feed grade damaged wheat (ADW) in lamb feeding, and assess the effect of ADW and its aflatoxin on intake, growth, haematology, blood biochemical constituents and immunological status. The ADW is a slightly mouldy feed resource, which is not suitable for human consumption. The experimental ADW contained dry matter (DM) 964, organic matter 974, crude protein 153, cellulose 205 and lignin 24, and starch 732 g/kg DM. ADW also contained aflatoxin B1 50 microg/kg due to mould infestation. Thirty-five weaner lambs (90 +/- 15 days of age and 16.1 +/- 0.82 kg body weight) in a randomized design were fed for 91 days on one of four composite feed mixtures (roughage to concentrate ratio of 25:75) containing 0, 118, 235, 353 or 470 g/kg ADW, which replaced equal amounts of maize and at these inclusion levels ADW replaced 0%, 25%, 50%, 75% and 100% maize in lamb diets respectively. Dry matter intake (DMI) was similar in different level of ADW fed lambs but ADW inclusion linearly (p = 0.016) reduced DMI. Average daily gain (g/day) was higher (p = 0.038) in lambs fed 353 g ADW diet. Haematological attributes viz. WBC, haemoglobin (Hb) and mean corpuscular volume did not affect by ADW feeding whereas it increased haematocrit, mean cell Hb and decreased neutrophil, RBC counts and mean cell Hb concentration. Blood glucose and urea-N increased whereas albumin and protein level reduced by ADW feeding. ADW feeding of lambs did not affect serum IgG level. The activities of serum aspartate aminotransferase, alkaline phosphates and acid phosphates were not affected, whereas alanine aminotransferase increased linearly (p = 0.001) with increasing levels of ADW. It is concluded that ADW containing aflatoxin B1 50 microg/kg DM can safely be incorporated in growing lamb feeding up to 353 g/kg diet without affecting growth and cellular immunity, however ADW may induce a transient alteration of hepatic enzymatic activities. Further aflatoxin content of the diet should be kept within permissible limits of respective country.

Effect of inclusion of tree leaves in feed on nutrient utilization and rumen fermentation in sheep

The effect of inclusion of tree leaves in mustard (Brassica campestris) straw (MS) based complete feed blocks (CFB) on nutrient utilization and rumen fermentation was studied in adult male sheep. Four types of CFB diets (Roughage:Concentrate:Molasses, 70:25:5) were prepared. The compaction process increased bulk density (g/cm(3)) of MSB, MSNL, MSSL and MSAL by 2.9, 1.79, 2.40 and 2.26 times, respectively. The dry matter intake (g/day) was higher (P<0.05) in MSSL and MSAL than in MSB. Digestibility coefficients of crude protein and hemicellulose increased (P<0.05) due to inclusion of tree leaves, while digestibility of dry matter and organic matter showed small improvement. However, inclusion of tree leaves did not affect digestibility of neutral detergent fibre, cellulose and energy. The concentration of total volatile fatty acids in rumen was significantly higher in MSAL than in MSB or MSSL. Blood bio-chemical parameters were within the normal physiological range in all the groups.

Yeast TFIID serves as a coactivator for Rap1p by direct protein-protein interaction

In vivo studies have previously shown that Saccharomyces cerevisiae ribosomal protein (RP) gene expression is controlled by the transcription factor repressor activator protein 1 (Rap1p) in a TFIID-dependent fashion. Here we have tested the hypothesis that yeast TFIID serves as a coactivator for RP gene transcription by directly interacting with Rap1p. We have found that purified recombinant Rap1p specifically interacts with purified TFIID in pull-down assays, and we have mapped the domains of Rap1p and subunits of TFIID responsible. In vitro transcription of a UAS(RAP1) enhancer-driven reporter gene requires both Rap1p and TFIID and is independent of the Fhl1p-Ifh1p coregulator. UAS(RAP1) enhancer-driven transactivation in extracts depleted of both Rap1p and TFIID is efficiently rescued by addition of physiological amounts of these two purified factors but not TATA-binding protein. We conclude that Rap1p and TFIID directly interact and that this interaction contributes importantly to RP gene transcription.

A type II ribonuclease H from Leishmania mitochondria: an enzyme essential for the growth of the parasite

Replication of kDNA in the mitochondrion of the kinetoplastid protozoan is an essential process. One of the proteins that may be required for the kDNA replication is the ribonuclease H (RNase H; EC 3.1.26.4). We have identified four distinct ribonuclease H genes in Leishmania, one type I (LRNase HI) and three type II (LRNase HIIA, LRNase HIIB and LRNase HIIC). We detail here molecular characterization of LRNase HIIC. The coding sequence of LRNase HIIC is 1425 bp in length encoding a 474-amino acid protein with a calculated molecular mass of approximately 53 kDa. While LRNase HIIC shares several conserved domains with mitochondrial RNase H from other organisms, it has three extra patches of amino acid sequences unique to this enzyme. Functional identity of this protein as an RNase H was verified by genetic complementation in RNase H-deficient Escherichia coli. The precursor protein may be enzymatically inactive as it failed to complement the E. coli mutant. The mitochondrial localization signal in LRNase HIIC is within the first 40 amino acid residues at the N-terminus. In vitro import of the protein by the mitochondrial vesicles showed that the precursor protein is processed to a 49-kDa protein. Antisense ablation of LRNase HIIC gene expression is lethal to the parasite cells both in vitro and in vivo. This study not only reveals the significance of the LRNase HIIC in the kinetoplast biology but also identifies a potential molecular target for antileishmanial chemotherapy.

Down-regulation of 7SL RNA expression and impairment of vesicular protein transport pathways by Leishmania infection of macrophages

The parasitic protozoan Leishmania specifically manipulates the expression of host macrophage genes during initial interactions, as revealed by mRNA differential display reverse transcription-PCR and cDNA microarray analyses. The genes that are down-regulated in mouse (J774G8) or human (U937) macrophages upon exposure to Leishmania include small RNA transcripts from the short interspersed element sequences. Among the short interspersed element RNAs that are down-regulated is 7SL RNA, which is the RNA component of the signal recognition particle. Because the microbicidal functions of macrophages profoundly count on vesicular protein transport processes, down-regulation of 7SL RNA may be significant in the establishment of infection by Leishmania in macrophage phagolysosomes. To evaluate whether down-regulation of 7SL RNA results in inhibition of signal recognition particle-mediated vesicular protein transport processes, we have tested and found that the targeting of proteins to the endoplasmic reticulum and plasma membrane and the secretion of proteins by macrophages are compromised in Leishmania-infected J774G8 and U937 cells. Knocking down 7SL RNA using small interfering RNA mimicked the effect of exposure of macrophages to Leishmania. The overexpression of 7SL RNA in J774G8 or U937 cells made these cells resistant to Leishmania infection, suggesting the possible biological significance of down-regulation of 7SL RNA synthesis in the establishment of infection by Leishmania. We conclude that Leishmania down-regulates 7SL RNA in macrophages to manipulate the targeting of many proteins that use the vesicular transport pathway and thus favors its successful establishment of infection in macrophages.

Down-regulation of UCRP and UBE2L6 in BRCA2 knocked-down human breast cells

To understand the effects of the transient ablation of BRCA2 gene expression in dividing human breast cells, we transiently knocked down BRCA2 mRNA in HMEC and other cells. Microarray analysis of mRNAs revealed the down-regulation of the mRNAs of ubiquitin cross-reacting protein (UCRP) and the E2 enzyme that help conjugating UCRP to its target proteins, namely UBE2L6 (UbcH8), in BRCA2 ablated cells. UCRP is an interferon regulated protein, involved in cell growth and cell cycle events by participating in the degradation/modulation of cell cycle regulatory proteins. Quantitative-PCR and Northern analysis confirmed down-regulation of UCRP and UBE2L6 with BRCA2 knockdown, respectively. Since UCRP and UCRPylation have critical roles in the innate immunity against viral infection and during pregnancy, our observation may indicate new roles of the BRCA2 protein.

Regulation of BRCA2 gene expression by the SLUG repressor protein in human breast cells

The expression of the breast cancer susceptibility protein BRCA2 is highly regulated in human breast, ovary, and pancreatic cells. BRCA2 is not expressed in the non-dividing cells, and expression is cell cycle stage-dependent and is elevated in the sporadic cancer cells. Mutational analysis of the upstream sequence of the human BRCA2 gene revealed an E2-box-containing silencer at the -701 to -921 position. The E2-box is essential for the cell-cycle stage-dependent activity of the silencer. We affinity-purified a 29-kDa silencer-binding protein (SBP) from the nuclear extracts of human breast cells BT-549 and MDA-MB-231. We explored whether the E2-box-binding repressor protein SLUG, which is of similar molecular size, is involved in the silencing process. Supershift assay with the purified SBP and anti-SLUG antibody revealed the identity of the SBP as SLUG. We found that silencer is inactive in the human breast cancer cells such as MDA-MB-468 and MCF-7 that do not express SLUG, further suggesting the involvement of SLUG in the BRCA2 gene silencing. Inducible expression of human SLUG in the dividing MDA-MB-468 cells reduced BRCA2 RNA levels with the activation of the silencer. Furthermore, small interfering RNA-mediated knockdown of SLUG mRNA in the BT-549 cells caused inhibition of the silencer function. Chromatin immunoprecipitation assays suggested that SLUG mediates its action by recruiting C-terminal-binding protein-1 (CtBP-1) and histone deacetylase-1 (HDAC-1) at the silencer E2-box. The general HDAC inhibitor, trichostatin A, inhibited the SLUG-mediated regulation of the silencer function. It thus appears that SLUG is a negative regulator for BRCA2 gene expression.

Effect of different strains of yeast on stereocontrolled reduction of 5-acetylisoxazolines

The stereocontrolled reduction of 3-aryl-5-acetylisoxazolines (1) to the corresponding alcohols (2 and 3) in the presence of four different yeast strains, recognized as Baker's yeast (commercial), Candida krusei (ATCC 14243), Pichia farinosa (NRRL Y110) and Sacchromyces sp. (soil isolate) have been attempted. The C. krusei was found to be diastereoselective for the (R)-1 while the Sacchromyces sp. led to complete reduction to yield the RS- and SS-alcohol in 1:1 ratio at 10 g/L scale.