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1.  Convergent RANK- and c-Met-Mediated Signaling Components Predict Survival of Patients with Prostate Cancer: An Interracial Comparative Study 
PLoS ONE  2013;8(9):e73081.
We reported (PLoS One 6 (12):e28670, 2011) that the activation of c-Met signaling in RANKL-overexpressing bone metastatic LNCaP cell and xenograft models increased expression of RANK, RANKL, c-Met, and phosphorylated c-Met, and mediated downstream signaling. We confirmed the significance of the RANK-mediated signaling network in castration resistant clinical human prostate cancer (PC) tissues. In this report, we used a multispectral quantum dot labeling technique to label six RANK and c-Met convergent signaling pathway mediators simultaneously in formalin fixed paraffin embedded (FFPE) tissue specimens, quantify the intensity of each expression at the sub-cellular level, and investigated their potential utility as predictors of patient survival in Caucasian-American, African-American and Chinese men. We found that RANKL and neuropilin-1 (NRP-1) expression predicts survival of Caucasian-Americans with PC. A Gleason score ≥8 combined with nuclear p-c-Met expression predicts survival in African-American PC patients. Neuropilin-1, p-NF-κB p65 and VEGF are predictors for the overall survival of Chinese men with PC. These results collectively support interracial differences in cell signaling networks that can predict the survival of PC patients.
PMCID: PMC3774681  PMID: 24066029
2.  Inhibition of β2-Microglobulin/Hemochromatosis Enhances Radiation Sensitivity by Induction of Iron Overload in Prostate Cancer Cells 
PLoS ONE  2013;8(7):e68366.
Bone metastasis is the most lethal form of several cancers. The β2-microglobulin (β2-M)/hemochromatosis (HFE) complex plays an important role in cancer development and bone metastasis. We demonstrated previously that overexpression of β2-M in prostate, breast, lung and renal cancer leads to increased bone metastasis in mouse models. Therefore, we hypothesized that β2-M is a rational target to treat prostate cancer bone metastasis.
In this study, we demonstrate the role of β2-M and its binding partner, HFE, in modulating radiation sensitivity and chemo-sensitivity of prostate cancer. By genetic deletion of β2-M or HFE or using an anti-β2-M antibody (Ab), we demonstrate that prostate cancer cells are sensitive to radiation in vitro and in vivo. Inhibition of β2-M or HFE sensitized prostate cancer cells to radiation by increasing iron and reactive oxygen species and decreasing DNA repair and stress response proteins. Using xenograft mouse model, we demonstrate that anti-β2-M Ab sensitizes prostate cancer cells to radiation treatment. Additionally, anti-β2-M Ab was able to prevent tumor growth in an immunocompetent spontaneous prostate cancer mouse model. Since bone metastasis is lethal, we used a bone xenograft model to test the ability of anti-β2-M Ab and radiation to block tumor growth in the bone. Combination treatment significantly prevented tumor growth in the bone xenograft model by inhibiting β2-M and inducing iron overload. In addition to radiation sensitive effects, inhibition of β2-M sensitized prostate cancer cells to chemotherapeutic agents.
Since prostate cancer bone metastatic patients have high β2-M in the tumor tissue and in the secreted form, targeting β2-M with anti-β2-M Ab is a promising therapeutic agent. Additionally, inhibition of β2-M sensitizes cancer cells to clinically used therapies such as radiation by inducing iron overload and decreasing DNA repair enzymes.
PMCID: PMC3707913  PMID: 23874600
3.  Phase I Dose Escalation, Pharmacokinetic and Pharmacodynamic Study of Naptumomab Estafenatox Alone in Patients With Advanced Cancer and With Docetaxel in Patients With Advanced Non–Small-Cell Lung Cancer 
Journal of Clinical Oncology  2009;27(25):4116-4123.
Two phase I studies were conducted of ABR-217620 alone or in combination with docetaxel. This is a recombinant fusion protein consisting of a mutated variant of the superantigen staphylococcal enterotoxin E (SEA/E-120) linked to fragment antigen binding moiety of a monoclonal antibody recognizing the tumor-associated antigen 5T4.
Patients and Methods
Patients with non–small-cell lung cancer (NSCLC), pancreatic cancer (PC), and renal cell cancer (RCC) received 5 daily boluses of ABR-217620 (3-month cycles) in escalating doses to determine the maximum-tolerated dose (MTD; ABR-217620 dose escalation monotherapy [MONO] study). Doses were selected based on individual patient anti–SEA/E-120 titers pretreatment. Patients with NSCLC received 4 daily, escalating doses of ABR-217620 followed by docetaxel in 21-day cycles (ABR-217620 dose escalation combination with docetaxel [COMBO] study).
Thirty-nine patients were enrolled in the MONO study and 13 were enrolled in the COMBO study. The monotherapy MTD was 26 μg/kg (NSCLC and PC) and 15 μg/kg (RCC). Dose-limiting toxicities (DLTs) in the MONO study were fever, hypotension, acute liver toxicity, and vascular leak syndrome. In the COMBO study, the MTD was 22 μg/kg (neutropenic sepsis). Adverse events included grade 1 to 2 fever, hypotension, nausea, and chills. Treatment caused a systemic increase of inflammatory cytokines and selective expansion of SEA/E-120 reactive T-cells. Tumor biopsies demonstrated T-cell infiltration after therapy. Fourteen patients (36%) had stable disease (SD) on day 56 of the MONO study. Two patients (15%) in the COMBO study had partial responses, one in a patient with progressive disease on prior docetaxel, and five patients (38%) had SD on day 56.
ABR-217620 was well tolerated with evidence of immunological activity and antitumor activity.
PMCID: PMC2734423  PMID: 19636016
4.  Mitochondrial DNA Mutation Stimulates Prostate Cancer Growth in Bone Stromal Environment 
The Prostate  2009;69(1):1-11.
Background and Objectives
Mitochondrial DNA (mtDNA) mutations, inherited and somatically acquired, are common in clinical prostate cancer. We have developed model systems designed to study specific mtDNA mutations in controlled experiments. Because prostate cancer frequently metastasizes to bone we tested the hypothesis that mtDNA mutations enhance prostate cancer growth and survival in the bone microenvironment.
The pathogenic nucleotide position (np) 8993 mDNA mutation was introduced into PC3 prostate cancer cells by cybrid formation. Wildtype and mutant cybrids were grown as nude mouse subcutaneous xenografts with or without bone stromal cell co-inoculation. Cybrids were also grown in the intratibial space. Tumor growth was assayed by direct tumor measurement and luciferase chemiluminescence. Gene expression was assayed using cDNA microarrays confirmed by real time PCR, western blot analysis and immunohistochemistry.
Cybrids with the 8993 mtDNA mutation grew faster than wildtype cybrids. Further growth acceleration was demonstrated in the bone microenvironment. A thirty-seven gene molecular signature characterized the growth advantage conferred by the mtDNA mutation and bone microenvironment. Two genes of known importance in clinical prostate cancer, FGF1 and FAK, were found to be substantially upregulated only when both mtDNA mutation and bone stromal cell were present.
The ATP6 np 8993 mtDNA mutation confers a growth advantage to human prostate cancer that is most fully manifest in the bone microenvironment. The identification of specific molecular alterations associated with mtDNA mutation and growth in bone may allow new understanding of prostate cancer bone metastasis.
PMCID: PMC2753601  PMID: 18850577

Results 1-4 (4)