Subramanyam Chittivelu

Inhibition of invasion, angiogenesis, tumor growth, and metastasis by adenovirus-mediated transfer of antisense uPAR and MMP-9 in non–small cell lung cancer cells

Lung cancer is currently the leading cause of cancer deaths in the United States. Conventional therapeutic treatments, including surgery, chemotherapy, and radiation therapy, have achieved only limited success. The overexpression of proteases, such as urokinase-type plasminogen activator (uPA), its receptor (uPAR), and matrix metalloproteinases (MMP), is correlated with the progression of lung cancer. In the present study, we used a replication-deficient adenovirus capable of expressing antisense uPAR and antisense MMP-9 transcripts to simultaneously down-regulate uPAR and MMP-9 in H1299 cells. Ad-uPAR-MMP-9 infection of H1299 cells resulted in a dose- and time-dependent decrease of uPAR protein levels and MMP-9 activity as determined by Western blotting and gelatin zymography, respectively. Corresponding immunohistochemical analysis also showed that Ad-uPAR-MMP-9 infection inhibited uPAR and MMP-9 expression. As shown by Boyden chamber assay, Ad-uPAR-MMP-9 infection significantly decreased the invasive capacity of H1299 cells compared with mock and Ad-CMV (empty vector)–infected cells in vitro. Furthermore, Ad-uPAR-MMP-9 infection inhibited capillary-like structure formation in H1299 cells cocultured with endothelial cells in a dose-dependent manner compared with mock- and Ad-CMV-infected cells. Ad-uPAR-MMP-9 injection caused the regression of s.c. induced tumors after s.c. injection with H1299 lung cancer cells and inhibited lung metastasis in the metastatic model with A549 cells. These data suggest that Ad-uPAR-MMP-9 shows its antitumor activity against both established and early phases of lung cancer metastases by causing the destruction of the tumor vasculature. In summary, adenovirus-mediated inhibition of uPA-uPAR interaction and MMP-9 on the cell surface may be a promising anti-invasion and antimetastatic strategy for cancer gene therapy.

Adenovirus-mediated small interfering RNA against matrix metalloproteinase-2 suppresses tumor growth and lung metastasis in mice

Matrix metalloproteinases (MMP) are a group of proteinases that have normal physiologic roles degrading and remodeling the extracellular matrix. They also have multiple roles in different stages of tumor progression. Elevated levels of MMPs have been observed in many tumors; these increases have a strong association with the invasive phenotype. MMP-2 and MMP-9 are particularly involved in cancer invasion and metastasis. MMP inhibitors are currently being tested as therapeutic agents for a number of cancers in both preclinical models and in clinical trials. To date, clinical trials using this strategy have had limited efficacy. A major concern is the lack of specificity of commercially available MMP inhibitors. An adenoviral vector expressing small interfering RNA against the MMP-2 gene (Ad-MMP-2) was constructed to specifically inhibit MMP-2 expression. The effect of Ad-MMP-2 on invasion, angiogenesis, tumor growth, and metastasis of A549 lung cancer cell was evaluated. Ad-MMP-2 infection of lung cancer cells showed specific down-regulation of MMP-2 protein, activity, and transcription as determined by Western blotting, gelatin zymography, and reverse transcription-PCR. Ad-MMP-2 inhibition also mitigated lung cancer invasion and migration, and reduced tumor cell–induced angiogenesis in vitro. In an experimental metastatic lung tumor model, treatment of established tumors by Ad-MMP-2 inhibited s.c. tumor growth and formation of lung nodules in mice. Adenoviral-mediated RNA interference against MMP-2 has significant therapeutic potential for lung cancer and exerts some of this effect by inhibiting angiogenesis. [Mol Cancer Ther 2006;5(9):2289–99]

Suppression of tumor cell invasiveness and in vivo tumor growth by microRNA-874 in non-small cell lung cancer.

MicroRNAs are a novel family of small non-coding RNAs that regulate the expression of several genes involved in normal development as well as human disorders including cancer. Here we show that miR-874 plays a tumor suppressor role in non-small cell lung cancer (NSCLC) in vitro and in vivo. In silico target prediction analysis revealed numerous genes associated with tumor progression including MMP-2 and uPA as the putative target genes of miR-874. Our preliminary in situ hybridization experiments demonstrated the diminution of miR-874 expression in lung cancer tissues compared to their normal counter parts. Overexpression of miR-874 in CD133-positive cancer stem cell (CSC) population led to a significant loss in CSC-phenotype and enhanced sphere de-differentiation into epithelial-like cells. Restoration of miR-874 expression drastically reduced cell invading ability in comparison to mock and control-miR-treated cells by suppressing the protein levels of MMP-2 and uPA. In in vivo experiments, miR-874 treatment decreased orthotopic tumor growth in nude mice compared to mock and control-miR treatments. Further, the immunoreactivity of human anti-MMP-2 and anti-uPA was significantly reduced in tumor sections from mice that received miR-874 treatment. In conclusion, our study highlights the possible tumor suppressor role of miR-874 in NSCLC-initiating cells and suggests miR-874 as a potential target in the treatment of NSCLC.

A devastating cardiovascular event in an adult cystic fibrosis patient: An unforeseen outcome of increasing life expectancy

The improving life expectancy for CF is known to be one of the biggest success stories in medicine. Life expectancy has increased from 6 months during the early 20th century to 42.7 years from in 2012–2016. As the life expectancy of CF patients has increased, it is important to consider other co-morbidities that these patients may encounter, and the impact this may have on their morbidity and mortality. We present a case of a 33-year-old male admitted to the hospital for a CF exacerbation who had an acute neurological decompensation due to an infarction of his right occipital and posterior temporal lobe.

A diagnosis of late-onset Myasthenia gravis unmasked by topical antibiotics

ABSTRACT Myasthenia Gravis (MG) is a disorder of the neuromuscular junction (NMJ) that manifests as fluctuating fatiguable weakness of the muscles. There are many factors that can exacerbate myasthenia symptoms including a variety medications and drugs, systemic illness, and pregnancy. A number of medications have been implicated in exacerbating MG symptoms, including aminoglycosides. We present a case of an elderly female with newly diagnosed MG following the use of tobramycin eye drops for 3 days. There have been limited reports in the literature of topical medications that exacerbate MG symptoms. Clinicians prescribing tobramycin eye drops (or other associated medications) should have a high index of suspicion of MG as early discontinuation and therapy will limit long-term morbidity and mortality in these patients.

Acute Chest Syndrome Progressing to ARDS in a Patient of 25-Week Gestation

Acute chest syndrome is a complication of sickle cell disease and represents the highest cause of mortality in those afflicted with the disorder. Pregnancy represents an increased risk for complications of sickle cell disease in both the mother and fetus. We present a case of a 20-year-old patient with known sickle cell disease who was at 25-week gestation and developed acute chest syndrome refractory to conventional therapies and requiring emergency cesarean section. Following delivery, the patient developed acute respiratory distress syndrome (ARDS) requiring extracorporeal membrane oxygenation (ECMO). The patient and infant eventually made full recoveries. This case highlights the importance of aggressive management of ACS and careful monitoring in a pregnant patient.

Drug-induced dyspnea versus cystic fibrosis exacerbation: a diagnostic dilemma

Cystic fibrosis (CF) is a disease caused by a mutation in the cystic fibrosis transmembrane conductance regulator protein in the epithelial membrane, and affects at least 30,000 people in the USA. There are between 900 and 1000 new cases diagnosed every year. Traditionally, CF has been treated symptomatically with pancreatic enzymes, bronchodilators, hypertonic saline, and pulmozyme. In July 2015, the US Food and Drug Administration approved Orkambi (lumacaftor/ivacaftor), a combination drug that works on reversing the effects of the defective cystic fibrosis transmembrane conductance regulator protein. Orkambi and mucolytics decrease the viscosity of mucous secretions, leading to an accumulation of hypoviscous fluid in the alveoli, resulting in dyspnea. This presentation can be mistaken for an infective exacerbation. We present a case in which a young female with CF recently started on Orkambi therapy presented to her primary care physician with dyspnea and increased respiratory secretions and was admitted to the hospital for 2 weeks of intravenous and inhaled antibiotic therapy for a presumed CF exacerbation. We highlight this case to bring awareness and educate patients and clinicians of the side-effect profile of Orkambi therapy with an intent to avoid unnecessary hospitalizations, inpatient antibiotics, and other costly medical services.

Abstract 5219: MicroRNA-874 impedes angiogenesis in non-small cell lung cancer

Proceedings: AACR Annual Meeting 2014; April 5-9, 2014; San Diego, CA MicroRNAs (miRs) are short (20-24nt) non-coding RNAs that are involved in post-transcriptional regulation of gene expression in eukaryotes by affecting both the stability and translation of mRNAs. MicroRNAs play crucial roles in normal biological processes and are commonly dysregulated in human diseases. Thus far, miRs have been shown to act as either tumor suppressor genes or oncogenes in driving critical gene expression pathways in cancer stem cells in a wide range of human malignancies, including non-small cell lung cancer (NSCLC).We previously found that miR-874 could suppress tumor growth and metastasis of NSCLC. Since angiogenesis is important for tumor growth and metastasis, in this study, we further investigated the possible roles of miR-874 in tumor angiogenesis. Attenuation of miR-874 expression in histological sections of NSCLC tumors and the CD133 positive population of NSCLC cells (NSCLC-initiating cells; NSCLC-ICs), as compared to its normal counterparts, was observed by in situ hybridization and real time quantitative PCR, respectively. Tumor-conditioned medium from NSCLC-ICs induced significantly high levels of endothelial cell capillary network and neovascularization in vivo; whereas, re-expression of miR-874 in NSCLC-ICs inhibited this capillary network formation ability by suppressing the protein levels of VEGF, Stat3, MMP-2, uPA and PI3K. Further, miR-874-treatment decreased in vivo angiogenesis and pre-established orthotopic tumor growth in nude mice as compared to mock- and control-miR-treatments. Immunohistochemical analysis revealed a significant decrease in the expression of VEGF, Stat3 and microvessel density (CD31 levels) in xenograft tumor sections from miR-874-treated mice. In conclusion, our study highlights the possible anti-angiogenic role of miR-874 in NSCLC-initiating cells and presents a new, hopeful therapeutic target and prognostic marker for NSCLC. Citation Format: Chandramu Chetty, Dilip R. Maddirela, Venkateswara R. Gogineni, Subramanyam Chittivelu, Jasti S. Rao, Bhagavatula Moorthy. MicroRNA-874 impedes angiogenesis in non-small cell lung cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 5219. doi:10.1158/1538-7445.AM2014-5219

Abstract 3070: Suppression of tumor cell invasiveness and in vivo tumor growth by microRNA-874 in non-small cell lung cancer.

Proceedings: AACR 104th Annual Meeting 2013; Apr 6-10, 2013; Washington, DC MicroRNAs are a family of small non-coding RNAs that regulate expression of many genes involved in normal development as well as human disorders including cancer. Here, we show that miR-874 plays a tumor suppressor role in non-small cell lung cancer (NSCLC) in vitro and in vivo. Interestingly, in silico target prediction analysis revealed numerous pro-oncogenes associated with tumor initiation, angiogenesis, invasion and migration, including MMP-2, uPA, NFAT5, PAK3, PAK7, LIMD, PECAM1, VEGF-A, Stat3, CUX1 and FGF1 as the putative target genes of miR-874. Our preliminary in situ hybridization experiments demonstrated the diminution of miR-874 expression in lung cancer tissues as compared to its normal counterparts. Overexpression of miR-874 in CD133-positive NSCLC cancer stem cell (CSC) population led to a significant loss in CSC phenotype and enhanced sphere de-differentiation into epithelial-like morphology. Restoration of miR-874 expression drastically reduced the invasive ability of cells in comparison to mock and control-miR treated cells by suppressing the protein levels of MMP-2 and uPA. Further, miR-874 treatment decreased orthotopic tumor growth in nude mice as compared to mock and control-miR treatments. Further, in vivo orthotopic tumor experiments in nude mice revealed the significant decrease in the immunoreactivity of human anti-MMP-2 and anti-uPA in miR-874-treated tumor sections. In conclusion, our study highlights the possible tumor suppressor role of miR-874 in NSCLC-initiating cells and suggests miR-874 as a potential target in the future treatment of NSCLC. Citation Format: Divya Kesanakurti, Dilip Maddirela, Subramanyam Chittivelu, Jasti S. Rao, Chandramu Chetty. Suppression of tumor cell invasiveness and in vivo tumor growth by microRNA-874 in non-small cell lung cancer. [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 3070. doi:10.1158/1538-7445.AM2013-3070 Note: This abstract was not presented at the AACR Annual Meeting 2013 because the presenter was unable to attend.