Ashutosh K. Pathak

Ursolic Acid Inhibits STAT3 Activation Pathway Leading to Suppression of Proliferation and Chemosensitization of Human Multiple Myeloma Cells

The activation of signal transducers and activators of transcription 3 (STAT3) has been linked with the proliferation of a variety of human cancer cells, including multiple myeloma. Agents that can suppress STAT3 activation have potential for prevention and treatment of cancer. In the present report, we tested an agent, ursolic acid, found in basil, apples, prunes, and cranberries, for its ability to suppress STAT3 activation. We found that ursolic acid, a pentacyclic triterpenoid, inhibited both constitutive and interleukin-6–inducible STAT3 activation in a dose- and time-dependent manner in multiple myeloma cells. The suppression was mediated through the inhibition of activation of upstream kinases c-Src, Janus-activated kinase 1, Janus-activated kinase 2, and extracellular signal–regulated kinase 1/2. Vanadate treatment reversed the ursolic acid–induced down-regulation of STAT3, suggesting the involvement of a tyrosine phosphatase. Indeed, we found that ursolic acid induced the expression of tyrosine phosphatase SHP-1 protein and mRNA. Moreover, knockdown of SHP-1 by small interfering RNA suppressed the induction of SHP-1 and reversed the inhibition of STAT3 activation, thereby indicating the critical role of SHP-1 in the action of this triterpene. Ursolic acid down-regulated the expression of STAT3-regulated gene products such as cyclin D1, Bcl-2, Bcl-xL, survivin, Mcl-1, and vascular endothelial growth factor. Finally, ursolic acid inhibited proliferation and induced apoptosis and the accumulation of cells in G1-G0 phase of cell cycle. This triterpenoid also significantly potentiated the apoptotic effects of thalidomide and bortezomib in multiple myeloma cells. Overall, these results suggest that ursolic acid is a novel blocker of STAT3 activation that may have a potential in prevention and treatment of multiple myeloma and other cancers. (Mol Cancer Res 2007;5(9):943–55)

Capsaicin is a novel blocker of constitutive and interleukin-6 - Inducible STAT3 activation

Purpose: Capsaicin, a constituent of green and red peppers, has been linked with suppression of tumorigenesis through a mechanism that is not well understood. Because the transcription factor signal transducer and activator of transcription 3 (STAT3) has been closely linked with tumorigenesis, we investigated the effect of this vanilloid on the STAT3 pathway in human multiple myeloma cells. Experimental Design: The effect of capsaicin on both constitutive and interleukin-6–induced STAT3 activation, associated protein kinases, and STAT3-regulated gene products involved in proliferation, survival and angiogenesis, cellular proliferation, and apoptosis in multiple myeloma cells was investigated. Results: We found that capsaicin inhibited constitutive activation of STAT3 in multiple myeloma cells in a dose- and time-dependent manner, with minimum effect on STAT5. Capsaicin also inhibited the interleukin-6–induced STAT3 activation. The activation of Janus-activated kinase 1 and c-Src, implicated in STAT3 activation, was also inhibited by the vanilloid, with no effect on extracellular signal-regulated kinase 1/2 activation. Pervanadate reversed the capsaicin-induced down-regulation of STAT3, suggesting the involvement of a protein tyrosine phosphatase. Capsaicin down-regulated the expression of the STAT3-regulated gene products, such as cyclin D1, Bcl-2, Bcl-xL, survivin, and vascular endothelial growth factor. Finally, capsaicin induced the accumulation of cells in G1 phase, inhibited proliferation, and induced apoptosis, as indicated by caspase activation. Capsaicin also significantly potentiated the apoptotic effects of Velcade and thalidomide in multiple myeloma cells. When administered i.p., capsaicin inhibited the growth of human multiple myeloma xenograft tumors in male athymic nu/nu mice. Conclusion: Overall, these results suggest that capsaicin is a novel blocker of the STAT3 activation pathway, with a potential role in the prevention and treatment of multiple myeloma and other cancers.

Oral Epithelium as a Surrogate Tissue for Assessing Smoking-Induced Molecular Alterations in the Lungs

Abstract The lungs and oral cavity of smokers are exposed to tobacco carcinogens. We hypothesized that tobacco-induced molecular alterations in the oral epithelium are similar to those in the lungs, and thus the oral epithelium may be used as a surrogate tissue for assessing alterations in the lungs. We used methylation-specific PCR to analyze promoter methylation of the p16 and FHIT genes at baseline and 3 months after intervention in 1,774 oral and bronchial brush specimens from 127 smokers enrolled in a randomized placebo-controlled chemoprevention trial. The association between methylation patterns in oral tissues and bronchial methylation indices (methylated sites / total sites per subject) was analyzed in a blinded fashion. At baseline, promoter methylation in bronchial tissue was present in 23% of samples for p16, 17% for FHIT, and 35% for p16 and FHIT; these percentages were comparable to methylation in oral tissue: 19% (p16), 15% (FHIT), and 31% (p16 and FHIT). Data from both oral and bronchial tissues were available for 125 individuals, in whom the two sites correlated strongly with respect to alterations (P < 0.0001 for both p16 and FHIT). At baseline, the mean bronchial methylation index was far higher in patients with oral tissue methylation (in either of the two genes; 39 patients) than in patients without oral tissue methylation (86 patients): 0.53 ± 0.29 versus 0.27 + 0.26 methylation index (P < 0.0001). Similar correlations occurred at 3 months after intervention. Our results support the potential of oral epithelium as a surrogate tissue for assessing tobacco-induced molecular damage in the lungs and thus have important implications for designing future lung cancer prevention trials and for research into the risk and early detection of lung cancer.

Delta DNMT3B variants regulate DNA methylation in a promoter-specific manner.

DNA methyltransferase 3B (DNMT3B) is critical in de novo DNA methylation during development and tumorigenesis. We recently reported the identification of a DNMT3B subfamily, DeltaDNMT3B, which contains at least seven variants, resulting from alternative pre-mRNA splicing. DeltaDNMT3Bs are the predominant expression forms of DNMT3B in human lung cancer. A strong correlation was observed between the promoter methylation of RASSF1A gene but not p16 gene (both frequently inactivated by promoter methylation in lung cancer) and expression of DeltaDNMT3B4 in primary lung cancer, suggesting a role of DeltaDNMT3B in regulating promoter-specific methylation of common tumor suppressor genes in tumorigenesis. In this report, we provide first experimental evidence showing a direct involvement of DeltaDNMT3B4 in regulating RASSF1A promoter methylation in human lung cancer cells. Knockdown of DeltaDNMT3B4 expression by small interfering RNA resulted in a rapid demethylation of RASSF1A promoter and reexpression of RASSF1A mRNA but had no effect on p16 promoter in the lung cancer cells. Conversely, normal bronchial epithelial cells with stably transfected DeltaDNMT3B4 gained an increased DNA methylation in RASSF1A promoter but not p16 promoter. We conclude that promoter DNA methylation can be differentially regulated and DeltaDNMT3Bs are involved in regulation of such promoter-specific de novo DNA methylation.

Impact of chronic obstructive pulmonary disease on respiratory status and quality of life in newly diagnosed patients with lung cancer

Objective and background:  A significant proportion of patients with lung cancer have associated COPD, which is considered an independent risk factor and cause of morbidity and mortality. However, the effect of COPD on respiratory status and quality of life in lung cancer has not been evaluated.

Effectiveness of Homoharringtonine (Omacetaxine Mepesuccinate) for Treatment of Acute Myeloid Leukemia: A Meta-Analysis of Chinese Studies

The present meta-analysis provides an overview on the effectiveness of homoharringtonine (HHT) combination regimens to treat acute myeloid leukemia (AML). Because most of these studies were performed in China, Chinese published clinical studies were used for the analysis. A search for studies from 2006 to 2013 of regimens containing HHT for AML treatment was performed using published studies and Chinese databases in Mandarin. The complete response (CR) and overall response (OR) rates were analyzed, and the fixed effects model and random effects model (REM) were calculated. The heterogeneity of the studies was calculated using Q homogeneity statistics. The meta-analysis included 21 studies (n = 1310, n = 229 pediatric, and n = 216 elderly). HHT was given in combination with cytarabine, daunorubicin, idarubicin, aclacinomycin, mitoxantrone, or granulocyte colony-stimulating factor. Heterogeneity was seen in all analyzed pools, but it was most pronounced in retrospective studies. Overall, the REM showed a CR rate of 65.2%. However, in studies in which HHT-containing regimens were compared to regimens without HHT, the CR rates were 69.1% in randomized trials and 62.8% in retrospective studies. Additionally, in studies with exclusively elderly patients, the CR rate was considerably lower than it was for the studies with mixed age populations (47.5% vs. 65.2%). Higher overall CR rates for HHT-containing regimens in AML treatment in the Chinese studies suggest that HHT could be an active agent in the management of AML. Additional clinical trials are warranted to evaluate the efficacy of HHT in AML treatment.

Multifocal Osteosarcoma Involving Unusual Sites

We report a rare case of multifocal osteosarcoma (MFOS) with involvement of skeleton, lung, bone marrow, and soft tissues, presenting with paraparesis, cranial nerve palsies, subcutaneous nodules, anemia, and thrombocytopenia. MFOS with involvement of unusual sites presents problems in diagnosis and has a poor prognosis. The literature on 11 cases of MFOS with extraosseus, extrapulmonary involvement reported previously has been reviewed.

Burden of Tyrosine Kinase Inhibitor Failure in Patients with Chronic Myeloid Leukemia

Tyrosine kinase inhibitors (TKIs) have been extremely effective at inducing remissions and slowing down the progression of chronic myeloid leukemia (CML) resulting in a significant reduction in morbidity and mortality. Most patients with CML must remain on TKIs indefinitely and many experience resistance or intolerance to TKIs requiring a switch to a second-line TKI, third-line TKI or more. The purpose of the current review is to examine the underlying factors and subsequent economic and quality of life burdens associated with TKI failure. We discuss the definitions and rates of TKI failure in CML and the extent to which mutations and non-adherence are associated with TKI failure. We also review the few studies that have examined economic and patient outcomes associated with TKI failure and we suggest avenues for future research examining the consequences of TKI failure.

Healthcare utilization and costs associated with tyrosine kinase inhibitor switching in patients with chronic myeloid leukemia.

Abstract Differences in healthcare utilization and costs were examined in chronic myeloid leukemia (CML) patients experiencing first-, second- and third-line tyrosine kinase inhibitor (TKI) therapy. Three CML cohorts were identified from the Truven Health MarketScan® database: No-Switch Cohort (NSc) = did not switch from first-line; One-Switch Cohort (OSc) = switched from first- to second-line only; Two-Switch Cohort (TSc) = switched to second- and then third-line. A total of 3510 patients were identified (mean = 54%; age = 55.8 years). NSc comprised 81% of the sample, OSc comprised 15% and 4% were in the TSc. First-line utilization/costs were significantly higher in the OSc/TSc compared to the NSc. Second-line hospital/outpatient visits and costs were higher in TSc compared to OSc. TSc experienced a significant cost increase from first- to second-line (

∆ DNMT3B4-del Contributes to Aberrant DNA Methylation Patterns in Lung Tumorigenesis.

4226.46), twice that of OSc (