Stress Activated P38 Mapk Regulates Cell Cycle via AP-1 Factors in Areca Extract Exposed Human Lung Epithelial Cells

Areca nut chewing habits are associated with several oral manifestations like leukoplakia, submucous fibrosis and oral squamous cell carcinoma. Although numerous evidence on areca toxicity is known but the mechanistic pathway of disease causation is to be studied. Aqueous areca nut extract treated A549 cells showed reduced cell viability by 48 h with IC50 value of 0.50%. The toxic nature of areca nut induced the production of reactive oxygen species with decreased anti-oxidant glutathione S transferase levels lead to altered redox homeostasis. PCR studies showed decreased mRNA levels of Jun and Fos AP-1 subunits on extract treatment by 48 h. The protein levels of PCNA, CDK4, RB, p53, c-Jun and c-Fos were found to be downregulated with upregulated CDK inhibitor p21 on extract treatment as compared to control. Results of FACS analysis further confirm G1/S phase cell cycle arrest on areca nut extract exposure. The regulation of downstream AP-1 subunits by MAPKs was studied by using specific inhibitors of ERK, JNK and p38 along with areca nut extract. Results showed the redox activation of MAP kinases down regulated the mRNA levels of AP-1 subunits in aqueous areca nut extract treated cells. Hence the present study aids in elucidating the role of MAP kinases in regulating the AP-1 subunits and their implications on target genes that are involved regulation of various cellular processes. Further, it would help in understanding the mechanistic aspects of the diseased state which may facilitate in designing of new therapeutic modalities that could help in cancer management

Stress activated p38 MAPK regulates cell cycle via AP-1 factors in areca extract exposed human lung epithelial cells

Abstract Areca nut chewing habits are associated with several oral manifestations like leukoplakia, submucous fibrosis and oral squamous cell carcinoma. Although numerous evidence on areca toxicity is known but the mechanistic pathway of disease causation is to be studied. Aqueous areca nut extract treated A549 cells showed reduced cell viability by 48 h with IC50 value of 0.50%. The toxic nature of areca nut induced the production of reactive oxygen species with decreased anti-oxidant glutathione S transferase levels lead to altered redox homeostasis. PCR studies showed decreased mRNA levels of Jun and Fos AP-1 subunits on extract treatment by 48 h. The protein levels of PCNA, CDK4, RB, p53, c-Jun and c-Fos were found to be downregulated with upregulated CDK inhibitor p21 on extract treatment as compared to control. Results of FACS analysis further confirm G1/S phase cell cycle arrest on areca nut extract exposure. The regulation of downstream AP-1 subunits by MAPKs was studied by using specific inhibitors of ERK, JNK and p38 along with areca nut extract. Results showed the redox activation of MAP kinases down regulated the mRNA levels of AP-1 subunits in aqueous areca nut extract treated cells. Hence the present study aids in elucidating the role of MAP kinases in regulating the AP-1 subunits and their implications on target genes that are involved regulation of various cellular processes. Further, it would help in understanding the mechanistic aspects of the diseased state which may facilitate in designing of new therapeutic modalities that could help in cancer management

Protein kinases orchestrate cell cycle regulators in differentiating BeWo choriocarcinoma cells

Abstract Choriocarcinoma, a trophoblastic neoplasia, occurs in women as an incidence of abnormal pregnancy. BeWo choriocarcinoma cells derived from the abnormal placentation are a suitable model system to study the factors associated with differentiation, invasion and other cellular events as an alternative to clinical samples. Many protein kinases orchestrate the complex events of cell cycle and in case of malignancy such regulators are found to be mutated. In the present study, BeWo cells treated with forskolin (Fo) and phorbol 12-myristate 13-acetate (PMA) were used to study the role of PKA (protein kinase A) and PKC (protein kinase C), respectively, on the expression pattern of differentiation-related genes, membrane markers, PKC isoforms and cell cycle regulators. The effect of Fo and PMA on the cell proliferation was assessed. Progressive induction of alkaline phosphatase level and formation of multinucleated differentiated cells were observed in the cells treated with Fo. Exposure of cells to Fo and PMA induced the mRNA transcripts of α-hCG, β-hCG and endoglin and down-regulates E-cadherin at mRNA and protein levels. Synergistic levels of both up- and down-regulated genes/proteins were observed when cells were treated with the combination of Fo and PMA. The mRNA levels of cyclin D1, cyclin E1, p21, Rb, p53, caspase-3 and caspase-8 decreased gradually during differentiation. Fo significantly inhibited the protein levels of PCNA, Rb, PKC-α and PMA stimulated mRNA expression of PKC-ε and PKC-δ. Further, failure in the activation of essential components of the cell cycle machinery caused G2/M phase arrest in differentiating BeWo cells

A study of clinical and etiological profile of community‑acquired pneumonia with special reference to atypical pneumonia

Background: Pneumonia is a leading cause of morbidity and mortality, especially in developing countries. The cause of community‑acquired pneumonia (CAP) is often difficult to establish. The most effective methods, especially for the diagnosis of atypical pathogens, are often invasive and may not always be justified. We studied the clinical and etiological profile of CAP, especially with regards to pathogens causing atypical pneumonia.Aims and Objectives: The aim is to study the clinical profile and etiological agents in patients suffering from CAP in our hospital and to detect proportion of atypical pathogens among these CAP patients.Methodology: From September 2012 to September 2014, 122 patients were diagnosed as having CAP and were included in this study. After sputum, blood culture, and serological evaluation, they were grouped as having typical and atypical pneumonia. Chi‑square test was used as statistical method to compare between these two groups.Results: Of 122 patients, 40.2% of patients were found to have typical organisms and 20.5% had atypical organisms causing pneumonia. The common etiological agents were Streptococcus pneumoniae (15.6%) and Klebsiella pneumoniae (8.2%) among typical pneumonia and Mycoplasma pneumoniae (7.4%) and Legionella pneumophila (5.7%) among atypical pneumonia cases.Conclusions: It is difficult to differentiate these causative agents by clinical features alone. Hence, appropriate serological, sputum, and blood culture should be carried out for early diagnosis, prompt treatment and also to reduce complications.Keywords: Community‑acquired pneumonia, etiology, indirect immunofluorescence, typical and atypical pathogen

Hemoperitoneum in dengue fever with normal coagulation profile

A 43-year-old male living in Bengaluru sought emergency services due to high-grade fever, headache, myalgia, abdominal pain and distension. Platelet count (except the first-96,000/mm 3 ) and coagulation profile was in normal limits. The dengue serology was positive for IgM and Ig G (immunoglobulin M and G) antibodies. Ultrasound abdomen showed gross ascites, mild bilateral pleural effusion and hepatosplenomegaly. The patient continued to have abdominal pain and progressive distention Ascitic tap was hemorrhagic. Later laparoscopy showed 1.5 liters peritoneal fluid with blood clots and mild diffuse congestion of the peritoneum. Liver, spleen and blood vessels were normal. Then what would be the possible mechanism to explain hemoperitoneum, is it the increased vascular permeability caused by the virus? India being endemic for dengue illness, it is an interesting and rare case presentation

Regulation of Jun and Fos AP-1 transcription factors by JNK MAPKs signaling cascade in areca nut extract treated KB cells

The edible endosperm of Areca catechu is recognized as a potent carcinogenic agent either consumed alone or in combination with tobacco. Habitual chewing of areca nut leads to orally potential malignant disorders which are highly effective in malignant transformation and thereby lead to oral carcinogenesis. Human buccal epithelial KB carcinoma cells were used as an experimental cell system to inspect the mechanistic act of aqueous extract of areca nut on biochemical status and their implications on transcriptional activation of cancer signaling cascade that could possibly trigger numerous oncogenic players and finally decides the cells fate. Extract treated cells showed reduced viability with altered balance between oxidants and antioxidants which lead to redox status and which is known to distort various biological processes within the cell system. Results of RT-PCR demonstrated decreased expression of BCl2, cell cycle regulators along with Activator Protein −1 (AP-1) components. While Bax, p16 and p21 mRNAs showed increased expression in extract treated KB cells. Likewise, the translational levels of proliferation cell nuclear antigen (PCNA), tumor suppressor p53, retinoblastoma (Rb) and cyclin dependent kinase 4 (CDK4) were decreased along with AP-1 subunits (c-Jun/c-Fos) with increased protein levels of p21 in extract treated KB cells. Further, the downstream activation and regulation of AP-1 transcription factors could be through stress activated c-Jun – N terminal Kinase (JNK) Mitogen Activated Protein Kinases (MAPKs) which downregulated both Jun and Fos mRNA transcripts in areca nut extract exposed KB cells. Thus, outcome of the study provides insights into mechanistic path of pathogenesis of areca related disorders. Further, it could aid in designing new therapeutic modalities that specific targets these oncogenic players and help in disease management