Oligomers of human histone chaperone NPM1 alter p300/KAT3B folding to induce autoacetylation.

BACKGROUND: p300 (KAT3B) lysine acetyltransferase activity is modulated under different physiological and pathological contexts through the induction of trans-autoacetylation. This phenomenon is mediated by several factors, mechanisms of which are not fully understood. METHODS: Through acetyltransferase assays using full-length, baculovirus-expressed KATs, the specificity of NPM1-mediated enhancement of p300 autoacetylation was tested. Chaperone assays and tryptophan fluorescence studies were performed to evaluate the NPM1-induced protein folding. The NPM1 oligomer-defective mutant characterization was done by glutaraldehyde-crosslinking. The small-molecule inhibitor of NPM1 oligomerization was used to confirm the absolute requirement of multimeric NPM1 in vivo. Immunohistochemistry analysis of oral cancer patient samples was done to uncover the pathophysiological significance of NPM1-induced p300 autoacetylation. RESULTS: We find that the histone chaperone NPM1 is a specific inducer of p300 autoacetylation. Distinct from its histone chaperone activity, NPM1 is a molecular chaperone of p300. The biophysical experiments suggest that there is a reversible binding between NPM1 and p300 which can modulate p300 acetyltransferase activity. Disruption of NPM1 oligomerization suggests that oligomeric NPM1 is essential for the induction of p300 autoacetylation. Significantly, we observe a concomitant hyper-autoacetylation of p300 with overexpression of NPM1 in oral cancer samples. CONCLUSION: NPM1 can specifically modulate p300 acetyltransferase activity through the enhancement of autoacetylation. The molecular chaperone activity and oligomerization of NPM1 play a pivotal role in this phenomenon. GENERAL SIGNIFICANCE: NPM1 is overexpressed in several solid cancers, the significance of which is unknown. Induction of p300 autoacetylation could be the cause of NPM1-mediated tumorigenicity.

Role of Matrix Metalloproteinase 9 in Predicting Lymph Node Metastases in Oral Squamous Cell Carcinoma.

Background Oral cancer is a common malignancy worldwide, with approximately 3,50,000 new cases diagnosed yearly. Out of many factors which affect the survival in patients with oral cancer, lymph node metastases are a major factor that reduces survival by 50%. Even though many biomarkers have been studied to predict lymph node metastasis, none have yet been accepted for routine use. Matrix metalloproteinases (MMPs) play a vital role in extracellular matrix (ECM) degradation, thus facilitating the invasive potential and the metastatic cascade of tumors. Of the different subtypes, multiple studies have demonstrated that matrix metalloproteinase 9 (MMP9) overexpression is often associated with the aggressive nature of the tumor. Therefore, this investigation is done to know the role of MMP9 in predicting lymph node metastasis in oral squamous cell carcinoma (OSCC). Aim To determine the immunohistochemical expression of MMP9 in OSCC and to find its association with lymph node metastasis. Settings and design It is a laboratory-based observational study. Materials and methods One hundred five histologically proven cases of OSCC were studied. Histopathological parameters like depth of invasion, presence of lymph node metastasis, grading, and TNM staging were done according to the 8th AJCC staging criteria. Both intensity and proportion of MMP9 expression were recorded. Statistical analysis For qualitative data, the Chi-square test was used as a test of significance. The p-value (probability that the result is true) of <0.05 was considered statistically significant after assuming all the rules of statistical tests. Results A higher expression of MMP9 was observed in 56.2% of cases and the higher expression correlated with the presence of lymph node metastases (p<0.001), an advanced stage of cancer (P <0.001), and grade of the tumor (p=0.003). Conclusion A positive association between MMP9 and lymph node metastasis and pathological TNM staging demonstrates MMP9 as a potential biomarker to predict the behavior of the tumor.

Comparative study of the efficacy and safety of intranasal azelastine hydrochloride and fluticasone furoate in the treatment of allergic rhinitis.

BACKGROUND: Allergic rhinitis (AR) is characterized by nasal itch, sneezing, watery or mucous rhinorrhea, nasal obstruction, and nasal or pharyngeal irritation. If untreated, AR can impair patients' quality of life (QOL). Azelastine hydrochloride (AH), histamine receptor antagonists, has anti-inflammatory and mast cell stabilizing properties. Fluticasone furoate (FF) is an anti-inflammatory agent with action on mast cells, eosinophils, neutrophils, macrophages, and lymphocytes. This study compares the efficacy and safety of these medications in AR. MATERIALS AND METHODS: Patients in the study had been clinically diagnosed with AR. In each group, there were 75 randomized patients who were to receive either FF (27.5 µg/spray) or AH (0.10%) intranasally twice daily. Assessment in terms of symptoms (total nasal symptom score), signs (endoscopic staging), QOL, eosinophil count, and sensory attributes was done at baseline, day 7, and day 15. Adverse effects were recorded, and the cost incurred was analyzed. Paired and umpaired t-test were used to compare symptom scores, QOL scores, and absolute eosinophil count within and between the groups, respectively. RESULTS: The total number of patients was 150 (76 males and 74 females); the mean age for FF group was 26.23 ± 5.2 years, and 26.96 ± 4.8 years for AH group. By day 7, there was a reduction of all scores in both medications, but the reduction in reduction was highly significant with FF (P = 0.001). There was a significant reduction (P = 0.001) in absolute eosinophil count both in blood and nasal smears by day 15 in both the groups; the reduction was significant (P = 0.001) with fluticasone. Adverse reactions were reported by 33.3% of patients receiving FF and 28% patients receiving AH. CONCLUSION: Fluticasone furoate produced sustained relief of symptoms, signs, and sensory attributes with a greater reduction in eosinophil count in comparison with AH in patients with allergic rhinitis.

Functional interplay between YY1 and CARM1 promotes oral carcinogenesis.

Coactivator associated arginine methyltransferase 1 (CARM1) has been functionally implicated in maintenance of pluripotency, cellular differentiation and tumorigenesis; where it plays regulatory roles by virtue of its ability to coactivate transcription as well as to modulate protein function as an arginine methyltransferase. Previous studies establish an oncogenic function of CARM1 in the context of colorectal and breast cancer, which correlate to its overexpressed condition. However, the mechanism behind its deregulated expression in the context of cancer has not been addressed before. In the present study we uncover an oncogenic function of CARM1 in the context of oral cancer, where it was found to be overexpressed. We also identify YY1 to be a positive regulator of CARM1 gene promoter, where silencing of YY1 in oral cancer cell line could lead to reduction in expression of CARM1. In this context, YY1 showed concomitant overexpression in oral cancer patient samples compared to adjacent normal tissue. Cell line based experiments as well as xenograft study revealed pro-neoplastic functions of YY1 in oral cancer. Transcriptomics analysis as well as qRT-PCR validation clearly indicated pro-proliferative, pro-angiogenic and pro-metastatic role of YY1 in oral cancer. We also show that YY1 is a substrate of CARM1 mediated arginine methylation, where the latter could coactivate YY1 mediated reporter gene activation in vivo. Taken together, CARM1 and YY1 were found to regulate each other in a positive feedback loop to facilitate oral cancer progression.

Oncogene c-fos and mutant R175H p53 regulate expression of Nucleophosmin implicating cancer manifestation.

Nucleophosmin (NPM1) is a nucleolar protein that is frequently overexpressed in various types of solid tumors. NPM1 is involved in several cellular processes that might contribute significantly to the increased proliferation potential of cancers. Previous reports suggest that NPM1 expression is highly increased in response to mitogenic and oncogenic signals, the mechanisms of which have not been elucidated extensively. Using constructs incorporating different fragments of the NPM1 promoter upstream to a Luciferase reporter gene, we have identified the minimal promoter of NPM1 and candidate transcription factors regulating NPM1 promoter activity by luciferase reporter assays. We have validated the roles of a few candidate factors at the transcriptional and protein level by quantitative reverse transcriptase PCR, immunoblotting and immunohistochemistry, and explored the mechanism of regulation of NPM1 expression using immunoprecipitation and chromatin immunoprecipitation assays. We show here that the expression of NPM1 is regulated by transcription factor c-fos, a protein that is strongly activated by growth factor signals. In addition, mutant p53 (R175H) overexpression also enhances NPM1 expression possibly through c-myc and c-fos. Moreover, both c-fos and mutant p53 are overexpressed in oral tumor tissues that showed NPM1 overexpression. Collectively, our results suggest that c-fos and mutant p53 R175H positively regulate NPM1 expression, possibly in synergism, that might lead to oncogenic manifestation.

Near-total laryngectomy in advanced laryngeal and pyriform cancers.

OBJECTIVE: To demonstrate the oncologic and physiological safety of near-total laryngectomy (NTL), its success in voice conservation, and its versatility for use in extensive resections that necessitate pharyngoplasty, and even in post-radiation recurrences. STUDY: In this study of 137 cases of NTL for cancer of the larynx (45 cases) and pyriform (92 cases), 86.9% were stage T3/T4 and 60.6% were N+. A total of 8.8% had extended pharyngeal resections necessitating patch pharyngoplasty (ENTLP). In 10.9% cases, NTL was used as salvage of post-radiation failures. Concurrent neck dissection was performed in 99 cases. RESULTS: A total of 70.1% was alive and disease-free at the last follow-up ranging from 12 months to 104 months (median, 35 mo). A total of 7.3% had local/locoregional recurrences and 11.7% had purely regional recurrences. The local control rate for post-radiation salvage with NTL was 93.3%. A total of 88.6% developed communicable speech, and the speech success rate was 100% in 12 cases of ENTLP. Complications included major wound dehiscence with total shunt breakdown in 2 cases (1.5%), pharyngeal leak requiring surgical intervention in 7 cases (3.6%), significant aspiration through the shunt necessitating completion laryngectomy in 1 case (0.7%), and complete shunt stenosis in 9 cases (6.6%). CONCLUSION: The study shows that NTL is an oncologically safe voice conservation procedure in advanced, lateralized laryngeal and pyriform cancers treated not only per primum, but also in carefully selected post-radiation failures. It has a high success rate of speech development even in those cases requiring extensive pharyngeal resections. Major complications were acceptably low.