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Metge B.J.,University of South Alabama | Liu S.,University of South Alabama | Riker A.I.,Ochsner Cancer Institute | Fodstad O.,University of South Alabama | And 3 more authors.
Oncology | Year: 2010

Objective: Breast cancer metastasis suppressor 1 (BRMS1) has been shown to functionally reduce the metastatic potential of melanoma. We also previously reported that BRMS1 negatively regulates the expression of the oncoprotein osteopontin (OPN). This study was carried out to assess the clinical relevance of BRMS1 and OPN in melanoma. Methods: Epigenetic regulation of BRMS1 was assessed by treating clinically derived melanoma cell lines with the demethylating agent 5-aza-2′-deoxycytidine (DAC) and the histone deacetylase inhibitor trichostatin A (TSA), followed by sodium bisulfite modification and methylation-specific PCR. Assessments of BRMS1 and OPN levels were performed using immunoblotting, quantitative real-time RT-PCR or reporter assays. RNA silencing was employed to abrogate the expression of OPN in melanoma-derived cell lines. The in vivo relevance of our findings was determined with experiments using athymic nude mice. Results: The reduced expression of BRMS1 in surgically excised melanoma specimens correlated with increased OPN expression during the progression from primary to metastatic melanoma. Treatment with DAC and TSA elevated BRMS1 levels, but caused an inconsistent change in OPN gene expression. Abrogating the expression of OPN in BRMS1-deficient metastatic melanoma-derived cell lines retarded the growth of melanoma tumor xenografts in athymic nude mice. Conclusion: While treatment with DAC and TSA may not be a universally applicable treatment alternative in melanoma, silencing the expression of OPN in metastatic melanomas that have lost expression of BRMS1 is a potential option for therapeutic intervention. Copyright © 2010 S. Karger AG.


Wang Y.,Peking University | Radfar S.,Yale University | Liu S.,Dana-Farber Cancer Institute | Riker A.I.,Ochsner Cancer Institute | Khong H.T.,University of South Alabama
BMC Medicine | Year: 2010

Background: Melanoma incidence is on the rise and advanced melanoma carries an extremely poor prognosis. Treatment options, including chemotherapy and immunotherapy, are limited and offer low response rates and transient efficacy. Thus, identification of new melanocyte/melanoma antigens that serve as potential novel candidate biomarkers in melanoma is an important area for investigation.Methods: Full length MITF-M and its splice variant cDNA were cloned from human melanoma cell line 624 mel by reverse transcription polymerase chain reaction (RT-PCR). Expression was investigated using regular and quantitative RT-PCR in three normal melanocytes (NHEM), 31 melanoma cell lines, 21 frozen melanoma tissue samples, 18 blood samples (pheripheral blood mononuclear cell; PBMC) from healthy donors and 12 non-melanoma cancer cell lines, including three breast, five glioma, one sarcoma, two kidney and one ovarian cancer cell lines.Results: A novel splice variant of MITF-M, which we named MITF-Mdel, was identified. The predicted MITF-Mdel protein contains two in frame deletions, 56- and 6- amino acid deletions in exon 2 (from V32 to E87) and exon 6 (from A187 to T192), respectively. MITF-Mdel was widely expressed in melanocytes, melanoma cell lines and tissues, but almost undetectable in non-melanoma cell lines or PBMC from healthy donors. Both isoforms were expressed significantly higher in melanoma tissues than in cell lines. Two of 31 melanoma cell lines expressed only one isoform or the other.Conclusion: MITF-Mdel, a novel melanocyte/melanoma-specific isoform of MITF-M, may serve as a potential candidate biomarker for diagnostic and follow-up purposes in melanoma. © 2010 Wang et al; licensee BioMed Central Ltd.


Zhou M.,University of South Alabama | Zhou M.,Central South University | Zhao Y.,University of South Alabama | Ding Y.,University of South Alabama | And 11 more authors.
Molecular Cancer | Year: 2010

Background: Taxol is one of the most effective chemotherapeutic agents for the treatment of patients with breast cancer. Despite impressive clinical responses initially, the majority of patients eventually develop resistance to Taxol. Lactate dehydrogenase-A (LDH-A) is one of the predominant isoforms of LDH expressed in breast tissue, which controls the conversion of pyruvate to lactate and plays an important role in glucose metabolism. In this study we investigated the role of LDH-A in mediating Taxol resistance in human breast cancer cells.Results: Taxol-resistant subclones, derived from the cancer cell line MDA-MB-435, sustained continuous growth in high concentrations of Taxol while the Taxol-sensitive cells could not. The increased expression and activity of LDH-A were detected in Taxol-resistant cells when compared with their parental cells. The downregulation of LDH-A by siRNA significantly increased the sensitivity of Taxol-resistant cells to Taxol. A higher sensitivity to the specific LDH inhibitor, oxamate, was found in the Taxol-resistant cells. Furthermore, treating cells with the combination of Taxol and oxamate showed a synergistical inhibitory effect on Taxol-resistant breast cancer cells by promoting apoptosis in these cells.Conclusion: LDH-A plays an important role in Taxol resistance and inhibition of LDH-A re-sensitizes Taxol-resistant cells to Taxol. This supports that Warburg effect is a property of Taxol resistant cancer cells and may play an important role in the development of Taxol resistance. To our knowledge, this is the first report showing that the increased expression of LDH-A plays an important role in Taxol resistance of human breast cancer cells. This study provides valuable information for the future development and use of targeted therapies, such as oxamate, for the treatment of patients with Taxol-resistant breast cancer. © 2010 Zhou et al; licensee BioMed Central Ltd.


Briggs J.J.,University of Oslo | Haugen M.H.,University of Oslo | Johansen H.T.,University of Oslo | Riker A.I.,Ochsner Cancer Institute | And 4 more authors.
BMC Cancer | Year: 2010

Background: High activity of cysteine proteases such as legumain and the cathepsins have been shown to facilitate growth and invasion of a variety of tumor types. In breast cancer, several recent studies have indicated that loss of the cysteine protease inhibitor cystatin E/M leads to increased growth and metastasis. Although cystatin E/M is normally expressed in the skin, its role in cysteine protease regulation and progression of malignant melanoma has not been studied.Methods: A panel of various non-melanoma and melanoma cell lines was used. Cystatin E/M and C were analyzed in cell media by immunoblotting and ELISA. Legumain, cathepsin B and L were analyzed in cell lysates by immunoblotting and their enzymatic activities were analyzed by peptide substrates. Two melanoma cell lines lacking detectable secretion of cystatin E/M were transfected with a cystatin E/M expression plasmid (pCST6), and migration and invasiveness were studied by a Matrigel invasion assay.Results: Cystatin E/M was undetectable in media from all established melanoma cell lines examined, whereas strong immunobands were detected in two of five primary melanoma lines and in two of six lines derived from patients with metastatic disease. Among the four melanoma lines secreting cystatin E/M, the glycosylated form (17 kD) was predominant compared to the non-glycosylated form (14 kD). Legumain, cathepsin B and L were expressed and active in most of the cell lines, although at low levels in the melanomas expressing cystatin E/M. In the melanoma lines where cystatin E/M was secreted, cystatin C was generally absent or expressed at a very low level. When melanoma cells lacking secretion of cystatin E/M were transfected with pCST6, their intracellular legumain activity was significantly inhibited. In contrast, cathepsin B activity was not affected. Furthermore, invasion was suppressed in cystatin E/M over-expressing melanoma cell lines as measured by the transwell Matrigel assay.Conclusions: These results suggest that the level of cystatin E/M regulates legumain activity and hence the invasive potential of human melanoma cells. © 2010 Briggs et al; licensee BioMed Central Ltd.


Marcus J.D.,Ochsner Cancer Institute | Mott F.E.,Georgia Regents University
Ochsner Journal | Year: 2014

Background: Communication is the cornerstone of good multidisciplinary medical care, and the impact of conversations about diagnosis, treatment, and prognosis is indisputable. Healthcare providers must be able to have difficult conversations that accurately describe diagnostic procedures, treatment goals, and the benefits and/or risks involved.Methods: This paper reviews the literature about the importance of communication in delivering bad news, the status of communication training, communication strategies, and psychosocial interventions.Results: Although many published guidelines address difficult communication, communication training is lacking. Consequently, many clinicians may have difficulties with, or in the worst-case scenario, avoid delivering bad news and discussing end-of-life treatment. Clinicians also struggle with how to have the last conversation with a patient and how to support patient autonomy when they disagree with a patient’s choices.Conclusion: There is a clinical imperative to educate physicians and other healthcare workers on how to effectively deliver information about a patient’s health status, diagnostic avenues to be explored, and decisions to be made at critical health junctions. Knowing how to implement the most rudimentary techniques of motivational interviewing, solutionfocused brief therapy, and cognitive behavioral therapy can help physicians facilitate conversations of the most difficult type to generate positive change in patients and families and to help them make decisions that minimize end-of-life distress. © 2014, Academic Division of Ochsner Clinic Foundation.


Zhou M.,University of South Alabama | Zhou M.,Central South University | Liu Z.,University of South Alabama | Zhao Y.,University of South Alabama | And 10 more authors.
Journal of Biological Chemistry | Year: 2010

Paclitaxel (Taxol) is an effective chemotherapeutic agent for treatment of cancer patients. Despite impressive initial clinical responses, the majority of patients eventually develop some degree of resistance to Taxol-based therapy. The mechanisms underlying cancer cells resistance to Taxol are not fully understood. MicroRNA (miRNA) has emerged to play important roles in tumorigenesis and drug resistance. However, the interaction between the development of Taxol resistance and miRNA has not been previously explored. In this study we utilized a miRNA array to compare the differentially expressed miRNAs in Taxol-resistant and their Taxol-sensitive parental cells. We verified that miR-125b, miR-221, miR-222, and miR-923 were up-regulated in Taxol-resistant cancer cells by real-time PCR. We further investigated the role and mechanisms of miR-125b in Taxol resistance. We found that miR-125b was up-regulated in Taxol-resistant cells, causing a marked inhibition of Taxol-induced cytotoxicity and apoptosis and a subsequent increase in the resistance to Taxol in cancer cells. Moreover, we demonstrated that the pro-apoptotic Bcl-2 antagonist killer 1 (Bak1) is a direct target of miR-125b. Down-regulation of Bak1 suppressed Taxol-induced apoptosis and led to an increased resistance to Taxol. Restoring Bak1 expression by either miR-125b inhibitor or re-expression of Bak1 in miR-125b-overexpressing cells recovered Taxol sensitivity, overcoming miR-125-mediated Taxol resistance. Taken together, our data strongly support a central role for miR-125b in conferring Taxol resistance through the suppression of Bak1 expression. This finding has important implications in the development of targeted therapeutics for overcoming Taxol resistance in a number of different tumor histologies. © 2010 by The American Society for Biochemistry and Molecular Biology, Inc.


Geng D.,University of Maryland, Baltimore | Zheng L.,Louisiana State University | Srivastava R.,University of Maryland, Baltimore | Velasco-Gonzalez C.,Louisiana State University | And 3 more authors.
Cancer Research | Year: 2010

The efficacy of T cell-based immunotherapy to treat cancer patients remains a challenge partly because of the weak activity toward subdominant tumor antigens (TAg) and to tumors expressing suboptimal TAg levels. Recent reports indicate that Toll-like receptor (TLR) stimulation on T cells can lower the activation threshold. In this study, we examined the antitumor activity and survival of TLR2-MyD88-stimulated CD8 T cells derived from melanoma patients and T-cell receptor transgenic pmel mice. TLR2-stimulated pmel CD8 T cells, but not TLR2-/-pmel or MyD88-/-pmel T cells, responded to significantly lower TAg levels and resulted in increased production of effector molecules and cytotoxicity. Wild-type or MyD88-/- mice treated with TLR2 ligand and pmel T cells, but not TLR2-/-pmel or MyD88 -/-pmel T cells, showed tumor regression of an established melanoma tumor. Overexpressing TLR2 in TAg-specific T cells eradicated tumors; four times fewer cells were needed to generate antitumor responses. The enhanced antitumor activity of TLR2-MyD88-stimulated T cells was associated with increased effector function but perhaps more importantly with improved survival of T cells. Activating TLR-MyD88 signals in patient-derived T cells also reduced the activation threshold to several weakly immunogenic TAgs, resulting in increased cytokine production, expansion, and cytotoxicity. These data highlight a previously unappreciated role for activating TLR-MyD88 signals in tumor-reactive T lymphocytes. ©2010 AACR.


Zhao Y.,University of South Alabama | Liu H.,University of South Alabama | Riker A.I.,Ochsner Cancer Institute | Fodstad O.,Norwegian Radium Hospital | And 3 more authors.
Frontiers in Bioscience | Year: 2011

Cancer cells are different from normal cells in their metabolic properties. Normal cells mostly rely on mitochondrial oxidative phosphorylation to produce energy. In contrast, cancer cells depend mostly on glycolysis, the aerobic breakdown of glucose into ATP. This altered energy dependency is known as the "Warburg effect" and is a hallmark of cancer cells. In recent years, investigating the metabolic changes within cancer cells has been a rapidly growing area. Emerging evidence shows that oncogenes that drive the cancer-promoting signals also drive the altered metabolism. Although the exact mechanisms underlying the Warburg effect are unclear, the existing evidence suggests that increased glycolysis plays an important role in support malignant behavior of cancer cells. A thorough understanding of the unique metabolism of cancer cells will help to design of more effective drugs targeting metabolic pathways, which will greatly impact the capacity to effectively treat cancer patients. Here we provide an overview of the current understanding of the Warburg effect upon tumor cell growth and survival, and discussion on the potential metabolic targets for cancer therapy.


Riker A.I.,Ochsner Cancer Institute | Zea N.,Ochsner Cancer Institute | Trinh T.,Ochsner Cancer Institute
Ochsner Journal | Year: 2010

We are seeing a record number of newly diagnosed skin cancers worldwide, with the incidence of melanoma increasing at a faster rate than almost all other cancers. As clinicians, we will have, by far, the greatest impact on reducing this incidence through better methods of early detection of melanoma and proven prevention methods and techniques. The medical community must enhance its efforts to increase its training of new health care personnel who are capable of diagnosing and treating this record number of patients with skin cancer. We must also try to increase the access to our limited number of dermatologists and provide novel ways of patient education such as through skin self-examinations, total body photography, and improved education for our children. By providing easier access to skin examinations, we will increase our chances of detecting melanoma in its earliest and most curable form. The dangers of indoor tanning beds and salons must be transparent to those that use them, focusing on expanding the oversight of such facilities by our local and federal governmental agencies while establishing legislation in several states to further limit their use to our youth, who are especially at high risk for developing melanoma in the future. This review will focus on the epidemiology, prevention, and detection of melanoma. © Academic Division of Ochsner Clinic Foundation.


Howell Jr. P.M.,University of South Alabama | Li X.,University of South Alabama | Riker A.I.,Ochsner Cancer Institute | Xi Y.,University of South Alabama
Ochsner Journal | Year: 2010

Melanoma is a highly aggressive and deadly skin cancer. Early intervention correlates with nearly 100% patient survival, but greater than 80% mortality is associated with advanced disease. Currently, few treatment options are available for patients with metastatic melanoma, and the global incidence of melanoma is increasing faster than that of other cancers. Therefore, it is vitally important to uncover and use genetic and epigenetic regulatory mechanisms at work during the development and progression of melanoma for better prevention, diagnosis, and clinical management. MicroRNA (miRNA) is a set of small, single-stranded, noncoding RNAs that target the 3'-untranslated region of an estimated 30% of all human genes to inhibit their expression. Our understanding of miRNA-mediated regulation of cancers has grown immensely over the past decade. Here we review currently available data on melanoma-associated miRNAs, highlighting those deregulated miRNAs targeting important genes and signaling pathways involved in the progression of melanocytes to primary and metastatic melanoma. Understanding the important roles of miRNAs in melanoma progression and metastasis development will contribute to the development of miRNA-targeted therapy in the future. © Academic Division of Ochsner Clinic Foundation.

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