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Animal body weights

Specificity of TFE3 antibody across TFE3 oncoproteins

A complete list of targeted genes in the PI3K/AKT signaling pathway with their associated miRNA from cluster 3.

List of chemokines/cytokines altered with PR/MR

Supplementary Figure Legend

Additional data on the role of PR/MR on tumor microenvironment

Androgen receptor (AR) plays a crucial role in the development and progression of prostate cancer. AR expression has also been reported in other solid tumors, including renal cell carcinoma (RCC), but its biological role here remains unclear. Through integrative analysis of a reverse phase protein array, we discovered increased expression of AR in an RCC patient–derived xenograft model of acquired resistance to the receptor tyrosine kinase inhibitor (RTKi) sunitinib. AR expression was increased in RCC cell lines with either acquired or intrinsic sunitinib resistance in vitro. An AR signaling gene array profiler indicated elevated levels of AR target genes in sunitinib-resistant cells. Sunitinib-induced AR transcriptional activity was associated with increased phosphorylation of serine 81 (pS81) on AR. Additionally, AR overexpression resulted in acquired sunitinib resistance and the AR antagonist enzalutamide-induced AR degradation and attenuated AR downstream activity in sunitinib-resistant cells, also indicated by decreased secretion of human kallikrein 2. Enzalutamide-induced AR degradation was rescued by either proteasome inhibition or by knockdown of the AR ubiquitin ligase speckle-type POZ protein (SPOP). In vivo treatment with enzalutamide and sunitinib demonstrated that this combination efficiently induced tumor regression in a RCC model following acquired sunitinib resistance. Overall, our results suggest the potential role of AR as a target for therapeutic interventions, in combination with RTKi, to overcome drug resistance in RCC.Significance: These findings highlight the therapeutic potential of targeting the androgen receptor to overcome RCC resistance to receptor tyrosine kinase inhibitors. Cancer Res; 78(11); 2886–96. ©2018 AACR.

Purpose:Translocation renal cell carcinoma (tRCC) represents a rare subtype of kidney cancer associated with various TFE3, TFEB, or MITF gene fusions that are not responsive to standard treatments for RCC. Therefore, the identification of new therapeutic targets represents an unmet need for this disease.Experimental Design:We have established and characterized a tRCC patient-derived xenograft, RP-R07, as a novel preclinical model for drug development by using next-generation sequencing and bioinformatics analysis. We then assessed the therapeutic potential of inhibiting the identified pathway using in vitro and in vivo models.Results:The presence of a SFPQ-TFE3 fusion [t(X;1) (p11.2; p34)] with chromosomal break-points was identified by RNA-seq and validated by RT-PCR. TFE3 chromatin immunoprecipitation followed by deep sequencing analysis indicated a strong enrichment for the PI3K/AKT/mTOR pathway. Consistently, miRNA microarray analysis also identified PI3K/AKT/mTOR as a highly enriched pathway in RP-R07. Upregulation of PI3/AKT/mTOR pathway in additional TFE3–tRCC models was confirmed by significantly higher expression of phospho-S6 (P < 0.0001) and phospho-4EBP1 (P < 0.0001) in established tRCC cell lines compared with clear cell RCC cells. Simultaneous vertical targeting of both PI3K/AKT and mTOR axis provided a greater antiproliferative effect both in vitro (P < 0.0001) and in vivo (P < 0.01) compared with single-node inhibition. Knockdown of TFE3 in RP-R07 resulted in decreased expression of IRS-1 and inhibited cell proliferation.Conclusions:These results identify TFE3/IRS-1/PI3K/AKT/mTOR as a potential dysregulated pathway in TFE3–tRCC, and suggest a therapeutic potential of vertical inhibition of this axis by using a dual PI3K/mTOR inhibitor for patients with TFE3–tRCC.

Pie chart for TFE3 binding sites

Purpose:Diet and healthy weight are established means of reducing cancer incidence and mortality. However, the impact of diet modifications on the tumor microenvironment and antitumor immunity is not well defined. Immunosuppressive tumor-associated macrophages (TAMs) are associated with poor clinical outcomes and are potentially modifiable through dietary interventions. We tested the hypothesis that dietary protein restriction modifies macrophage function toward antitumor phenotypes.Experimental Design:Macrophage functional status under different tissue culture conditions and in vivo was assessed by Western blot, immunofluorescence, qRT-PCR, and cytokine array analyses. Tumor growth in the context of protein or amino acid (AA) restriction and immunotherapy, namely, a survivin peptide–based vaccine or a PD-1 inhibitor, was examined in animal models of prostate (RP-B6Myc) and renal (RENCA) cell carcinoma. All tests were two-sided.Results:Protein or AA-restricted macrophages exhibited enhanced tumoricidal, proinflammatory phenotypes, and in two syngeneic tumor models, protein or AA-restricted diets elicited reduced TAM infiltration, tumor growth, and increased response to immunotherapies. Further, we identified a distinct molecular mechanism by which AA-restriction reprograms macrophage function via a ROS/mTOR-centric cascade.Conclusions:Dietary protein restriction alters TAM activity and enhances the tumoricidal capacity of this critical innate immune cell type, providing the rationale for clinical testing of this supportive tool in patients receiving cancer immunotherapies.

Effect of different rapamycin concentrations

Enzalutamide prevents Sunitinib induced AR nuclear localization. Real-time fluorescence live cell imaging of 786-0 cells expressing AR-EGFP pretreated with 500 nM Enzalutamide for 30 minutes does not show increase in AR nuclear localization following Sunitinib treatment (5uM Sunitinib t=30s).

Enriched KEGG PI3K/AKT signaling pathway visualization

Pie chart for TFE3 binding sites

ChiP-seq for TFE3 in UOK-146

Schema for multimodal inhibition in tRCC

Enzalutamide modulates the protein expression of sunitinib-induced AR regulated genes.

Supplementary Figure Legends

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Purpose: Translocation renal cell carcinoma (tRCC) represents a rare subtype of kidney cancer associated with various TFE3, TFEB, or MITF gene fusions that are not responsive to standard treatments for RCC. Therefore, the identification of new therapeutic targets represents an unmet need for this disease. Experimental Design: We have established and characterized a tRCC patient-derived xenograft, RP-R07, as a novel preclinical model for drug development by using next-generation sequencing and bioinformatics analysis. We then assessed the therapeutic potential of inhibiting the identified pathway using in vitro and in vivo models. Results: The presence of a SFPQ-TFE3 fusion [t(X;1) (p11.2; p34)] with chromosomal break-points was identified by RNA-seq and validated by RT-PCR. TFE3 chromatin immunoprecipitation followed by deep sequencing analysis indicated a strong enrichment for the PI3K/AKT/mTOR pathway. Consistently, miRNA microarray analysis also identified PI3K/AKT/mTOR as a highly enriched pathway in RP-R07. Upregulation of PI3/AKT/mTOR pathway in additional TFE3–tRCC models was confirmed by significantly higher expression of phospho-S6 (P < 0.0001) and phospho-4EBP1 (P < 0.0001) in established tRCC cell lines compared with clear cell RCC cells. Simultaneous vertical targeting of both PI3K/AKT and mTOR axis provided a greater antiproliferative effect both in vitro (P < 0.0001) and in vivo (P < 0.01) compared with single-node inhibition. Knockdown of TFE3 in RP-R07 resulted in decreased expression of IRS-1 and inhibited cell proliferation. Conclusions: These results identify TFE3/IRS-1/PI3K/AKT/mTOR as a potential dysregulated pathway in TFE3–tRCC, and suggest a therapeutic potential of vertical inhibition of this axis by using a dual PI3K/mTOR inhibitor for patients with TFE3–tRCC.

Purpose: Recent advances in immunotherapy highlight the antitumor effects of immune checkpoint inhibition despite a relatively limited subset of patients receiving clinical benefit. The selective class I histone deacetylase inhibitor entinostat has been reported to have immunomodulatory activity including targeting of immune suppressor cells in the tumor microenvironment. Thus, we decided to assess whether entinostat could enhance anti–PD-1 treatment and investigate those alterations in the immunosuppressive tumor microenvironment that contribute to the combined antitumor activity. Experimental Design: We utilized syngeneic mouse models of lung (LLC) and renal cell (RENCA) carcinoma and assessed immune correlates, tumor growth, and survival following treatment with entinostat (5 or 10 mg/kg, p.o.) and a PD-1 inhibitor (10 and 20 mg/kg, s.c.). Results: Entinostat enhanced the antitumor effect of PD-1 inhibition in two syngeneic mouse tumor models by reducing tumor growth and increasing survival. Entinostat inhibited the immunosuppressive function of both polymorphonuclear (PMN)- and monocytic-myeloid derived suppressor cell (M-MDSC) populations. Analysis of MDSC response to entinostat revealed significantly reduced arginase-1, iNOS, and COX-2 levels, suggesting potential mechanisms for the altered function. We also observed significant alterations in cytokine/chemokine release in vivo with a shift toward a tumor-suppressive microenvironment. Conclusions: Our results demonstrate that entinostat enhances the antitumor effect of PD-1 targeting through functional inhibition of MDSCs and a transition away from an immune-suppressive tumor microenvironment. These data provide a mechanistic rationale for the clinical testing and potential markers of response of this novel combination in solid tumor patients. Clin Cancer Res; 23(17); 5187–201. ©2017 AACR.

Purpose: Diet and healthy weight are established means of reducing cancer incidence and mortality. However, the impact of diet modifications on the tumor microenvironment and antitumor immunity is not well defined. Immunosuppressive tumor-associated macrophages (TAMs) are associated with poor clinical outcomes and are potentially modifiable through dietary interventions. We tested the hypothesis that dietary protein restriction modifies macrophage function toward antitumor phenotypes. Experimental Design: Macrophage functional status under different tissue culture conditions and in vivo was assessed by Western blot, immunofluorescence, qRT-PCR, and cytokine array analyses. Tumor growth in the context of protein or amino acid (AA) restriction and immunotherapy, namely, a survivin peptide–based vaccine or a PD-1 inhibitor, was examined in animal models of prostate (RP-B6Myc) and renal (RENCA) cell carcinoma. All tests were two-sided. Results: Protein or AA-restricted macrophages exhibited enhanced tumoricidal, proinflammatory phenotypes, and in two syngeneic tumor models, protein or AA-restricted diets elicited reduced TAM infiltration, tumor growth, and increased response to immunotherapies. Further, we identified a distinct molecular mechanism by which AA-restriction reprograms macrophage function via a ROS/mTOR-centric cascade. Conclusions: Dietary protein restriction alters TAM activity and enhances the tumoricidal capacity of this critical innate immune cell type, providing the rationale for clinical testing of this supportive tool in patients receiving cancer immunotherapies.

Androgen receptor (AR) plays a crucial role in the development and progression of prostate cancer. AR expression has also been reported in other solid tumors, including renal cell carcinoma (RCC), but its biological role here remains unclear. Through integrative analysis of a reverse phase protein array, we discovered increased expression of AR in an RCC patient–derived xenograft model of acquired resistance to the receptor tyrosine kinase inhibitor (RTKi) sunitinib. AR expression was increased in RCC cell lines with either acquired or intrinsic sunitinib resistance in vitro. An AR signaling gene array profiler indicated elevated levels of AR target genes in sunitinib-resistant cells. Sunitinib-induced AR transcriptional activity was associated with increased phosphorylation of serine 81 (pS81) on AR. Additionally, AR overexpression resulted in acquired sunitinib resistance and the AR antagonist enzalutamide-induced AR degradation and attenuated AR downstream activity in sunitinib-resistant cells, also indicated by decreased secretion of human kallikrein 2. Enzalutamide-induced AR degradation was rescued by either proteasome inhibition or by knockdown of the AR ubiquitin ligase speckle-type POZ protein (SPOP). In vivo treatment with enzalutamide and sunitinib demonstrated that this combination efficiently induced tumor regression in a RCC model following acquired sunitinib resistance. Overall, our results suggest the potential role of AR as a target for therapeutic interventions, in combination with RTKi, to overcome drug resistance in RCC. Significance: These findings highlight the therapeutic potential of targeting the androgen receptor to overcome RCC resistance to receptor tyrosine kinase inhibitors. Cancer Res; 78(11); 2886–96. ©2018 AACR.

Over the past decades, little progress has been made to improve the extremely low survival rates in pancreatic cancer patients. Extreme hypoxia observed in pancreatic tumors contributes to the aggressive and metastatic characteristics of this tumor and can reduce the effectiveness of conventional radiation therapy and chemotherapy. In an attempt to reduce hypoxia-induced obstacles to effective radiation treatment, we used a novel device, the implantable micro-oxygen generator (IMOG), for in situ tumor oxygenation. After subcutaneous implantation of human pancreatic xenograft tumors in athymic rats, the IMOG was wirelessly powered by ultrasonic waves, producing 30 μA of direct current (at 2.5 V), which was then utilized to electrolyze water and produce oxygen within the tumor. Significant oxygen production by the IMOG was observed and corroborated using the NeoFox oxygen sensor dynamically. To test the radiosensitization effect of the newly generated oxygen, the human pancreatic xenograft tumors were subcutaneously implanted in nude mice with either a functional or inactivated IMOG device. The tumors in the mice were then exposed to ultrasonic power for 10 min, followed by a single fraction of 5 Gy radiation, and tumor growth was monitored thereafter. The 5 Gy irradiated tumors containing the functional IMOG exhibited tumor growth inhibition equivalent to that of 7 Gy irradiated tumors that did not contain an IMOG. Our study confirmed that an activated IMOG is able to produce sufficient oxygen to radiosensitize pancreatic tumors, enhancing response to single-dose radiation therapy.

Myeloid-derived suppressor cells (MDSC) are important to the tumour microenvironment as they actively suppress the immune system and promote tumour progression and metastasis. These cells block T-cell activation in the tumour microenvironment, preventing anti-tumour immune activity. The ability of a treatment to alter the suppressive function of these cells and promote an immune response is essential to enhancing overall therapeutic efficacy. Interleukin-12 (IL-12) has the potential not only to promote anti-tumour immune responses but also to block the activity of cells capable of immune suppression. This paper identifies a novel role for IL-12 as a modulator of MDSC activity, with implications for IL-12 as a therapeutic agent. Treatment with IL-12 was found to alter the suppressive function of MDSC by fundamentally altering the cells. Interleukin-12-treated MDSC exhibited up-regulation of surface markers indicative of mature cells as well as decreases in nitric oxide synthase and interferon-γ mRNA both in vitro and in vivo. Treatment with IL-12 was also found to have significant therapeutic benefit by decreasing the percentage of MDSC in the tumour microenvironment and increasing the percentage of active CD8(+) T cells. Treatment with IL-12 resulted in an increase in overall survival accompanied by a reduction in metastasis. The findings in this paper identify IL-12 as a modulator of immune suppression with significant potential as a therapeutic agent for metastatic breast cancer.

Background: Translocation Renal Cell Carcinoma (tRCC) represents an aggressive subtype of kidney cancer associated with various gene fusions involving translocation of one of two members of micropthalmia transcription factor (MiT) family, TFE3 or TFEB. Despite the identification of multiple TFE3 gene fusions in tRCC, heterogeneous phenotype and various dysregulated signaling pathways resulting from variety of gene fusion partners pose a challenge to establish effective treatments for these patients. In this work, we assessed the role of wild type TFE3 (wt-TFE3) in RCC cell bearing TFE3 fusion with genes associated with pre-mRNA splicing factor machinery (NONO, SFPQ and PRCC).Methods: Endogenous SFPQ-TFE3 expressing cells, RP-RO7, were generated from patient derived xenograft established in NSG mice. UOK-109 and UOK-146 (kindly provided by Dr. Marston Lenehan, NCI) were used as endogenous NONO-TFE3 and PRCC-TFE3 expressing cells, respectively. RNA interference (RNAi) mediated knockdown with differential exon targeting strategy was employed to study wt-TFE3 loss of function in RP-R07, UOK-109 and UOK-146, respectively. Real time monitoring of cell viability assay with multiplex readout were developed to investigate the effect of wt-TFE3 loss of function in 2D and 3D culture system. Two different 3D models were used;1) Tumor growth model, in which cancer cell interaction with extracellular matrix and stromal cells were represented in a multiculture-spheroid system; 2) Invasion model, in which cell ability to invade basement membrane barrier was modeled with matrix restricted spheroid, and the invasion trajectories were observed and quantified. Exogenous expression of wt-TFE3-EGFP was utilized to study the protein subcellular localization in RP-R07, UOK-109 and UOK-146 2D cultures and 3D culture system.Results: Consistent with the expression of chimeric TFE3, wt-TFE3-EGFP ectopic expression demonstrated strong nuclear localization in RP-R07, UOK-109 and UOK-146. Multiplex readout of cells viability assay showed that transient loss of wt-TFE3 in RP-R07, UOK-109 and UOK-146 curtails the proliferation rate of these cells in 2D and 3D models in fusion partner dependent manner (P Citation Format: Nur P. Damayanti, Khunsha Ahmed, May Elbanna, Chinghai Kao, Roberto Pili. Investigating the role of wild-type TFE3 in renal cell carcinoma cells harboring TFE3 fusions with spliceosome machinery associated genes [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3109.

Background We explored multiple molecular mechanisms of the combination of docetaxel and an oncolytic prostate-restricted replication competent adenovirus (Ad) (PRRA) in advanced prostate cancer (PCa) models. The combinational therapy has potential to overcome the therapeutic limitations of poor virus distribution inside solid tumors. Methods We evaluated the effect of docetaxel on the antitumor efficacy and efficiency of virus transduction, transgene expression and virus distribution of PRRA in a prostate-specific antigen/prostate-specific membrane antigen-positive tumor xenograft model. We also evaluated the effect of docetaxel on apoptosis induction, cell killing and the efficiency of transgene expression and virus replication in vitro. Results Tumor growth inhibition was significantly enhanced when docetaxel was administrated before intratumor injection of PRRA. In vivo dual-photon microscopy and ex vivo fluorescence microscopy and immunohistochemistry showed that docetaxel increased transgene expression and expanded virus distribution. The combination of docetaxel and PRRA also increased cell apoptosis. In vitro, docetaxel significantly increased cell killing in PRRA-treated PCa cells. Docetaxel significantly increased Ad-mediated trangene expression independent of Ad binding receptors and replication capability. Docetaxel increased the activity of cytomegalovirus (CMV) promoter but not of a chimeric prostate-specific enhancer, resulting in higher transgene expression. The enhanced CMV promoter activity resulted from activation of p38 mitogen-activated protein kinase (MAPK) because inhibition of p38 MAPK blocked the docetaxel-induced increase in CMV promoter activity. Conclusions Combining docetaxel with an oncolytic PRRA improved therapeutic potential by expanding virus distribution and enhancing cell apoptosis and killing. These studies suggested a novel mechanism for enhancing the effect of therapeutic genes delivered by a PRRA. Copyright © 2010 John Wiley & Sons, Ltd.

Renal cell carcinoma (RCC) is the third most common urologic neoplasm. This aggressive malignancy has proven refractory to conventional treatment options. Antiangiogenic agents have shown early success in treating metastatic disease. The highly vascular nature of RCC appears particularly susceptible to this approach. This study investigates the potential of sustained expression of an endostatin-angiostatin fusion protein in an early-stage model of RCC to inhibit tumor growth and metastasis. Subcutaneous RCC-29 tumors were induced in athymic nude mice. Once tumors reached volumes of 10 and 25 mm(3), subjects received intratumoral injections of a nonreplicating adenoviral vector every 20 days until the conclusion of the trial. The mice were randomly assigned to three treatment groups: saline control, viral Ad-GFP control, and Ad-EndoAngio. Tumor volumes were measured twice weekly for 80 days. During days 40-50 of the trial, subjects underwent dual-photon optical imaging of the tumor vasculature to ascertain angiogenic changes. All animals underwent postmortem histopathological analysis to assess for metastatic disease in the kidney, lung, liver, brain, and spleen. Results indicate that tumors treated with Ad-EndoAngio displayed 97% growth reduction compared with controls (p < 0.001). Further, in vivo tumor vascular imaging illustrated a reduction in blood vessel number and lumen diameter size. Kaplan-Meier analysis suggested dramatic survival advantage with Ad-EndoAngio treatment. Importantly, histopathological examination demonstrated marked lung and liver metastasis suppression in the treatment arms. These results suggest that sustained EndoAngio gene therapy has effective antiangiogenic action against human RCC tumors and possesses potential as a novel treatment for metastatic renal cell carcinoma.

We investigated the anti-angiogenic and antitumor properties of 2 adenoviral vectors expressing the endostatin-angiostatin fusion protein Ad-EndoAngio and the soluble, endothelium specific tyrosine kinase receptor Ad-Tie2 in a mouse renal cell carcinoma xenograft model.A total of 29 bilateral subcutaneous renal cell carcinomas were induced in athymic nude mice. On days 2 and 10 following tumor establishment the mice were intratumorally injected with an adenoviral vector in the right flank only. Seven treatment groups were randomly assigned, including the control group of 7 mice, the Ad-GFP control group of 7, the Ad-Tie2 group of 9, the Ad-EndoAngio group of 8, the Ad-GFP plus Ad-Tie2 group of 7, the Ad-GFP plus Ad-EndoAngio group of 9 and the Ad-EndoAngio plus Ad-Tie2 group of 8. Tumor volume was measured biweekly for 60 days. Additionally, each treatment group was administered fluorescent rhodamine conjugated bovine serum albumin dye for vascular imaging. After establishing skin windows overlying the tumors dual photon optical imaging was used to qualitatively assess the tumor vasculature.Tumors treated with Ad-EndoAngio, Ad-GFP plus Ad-EndoAngio and Ad-EndoAngio plus Ad-Tie2 demonstrated 82%, 83% and 87% growth reduction, respectively, compared to controls (p0.001). Furthermore, in vivo imaging revealed a decrease in the number of blood vessels, lumen diameter and flow velocity in these treatment groups.Adenoviral vectors expressing endostatin-angiostatin fusion protein have effective anti-angiogenic action against human renal cell carcinoma cells as well as potential as a novel treatment for metastatic renal cell carcinoma.

We evaluated the long-term safety and efficacy of Ad-OC-TK (recombinant adenoviral vector carrying an osteocalcin promoter-driven herpes simplex virus thymidine kinase gene) plus VAL (valacyclovir) gene therapy for hormone-refractory prostate cancer. Ad-OC-TK/VAL therapy is the first in vivo adenovirus-mediated gene therapy to be used to treat metastatic prostate cancer, including bone metastasis. Six patients were enrolled in this trial, and two doses of Ad-OC-TK (2.5 x 10(9) or 2.5 x 10(10) plaque-forming units) were injected into locally recurrent tumor or bone metastasis on day 1 and day 8. Patients were also given VAL (3 g/day) for 21 days. Safety and efficacy were evaluated for at least 8 months in each patient. All patients tolerated this therapy with no serious adverse events. One prostate-specific antigen (PSA) response (from 318.3 to 4.9 ng/ml) was observed with a time to PSA progression (TTP) of 12 months. Docetaxel (30 mg/m2 per week) and estramustine (560 mg/day) combination chemotherapy (DE) was given to three docetaxel-naive patients on PSA failure after gene therapy. All three patients had a PSA response to DE therapy with 21, 7, and 4 months of TTP. These results suggest that additional trials are warranted.

Purpose: Recent studies showed that Fas ligand (FasL) induced apoptosis in tumor cells and suppressed the immune response in several types of tumors. However, the toxicity of FasL limited further administration. This study delivered FasL in prostate cancer cells using an improved prostate-restricted replicative adenovirus (PRRA), thereby improving the antitumor effect while decreasing systemic toxicity. Experimental Design: We designed a FasL-armed PRRA, called AdIU3, by placing adenoviral E1a and E4 genes, FasL cDNA, and E1b gene under the control of two individual PSES enhancers. Tissue-specific viral replication and FasL expression were analyzed, and the tumor killing effect of AdIU3 was investigated both in vitro and in vivo using androgen-independent CWR22rv s.c. models via local administration and bone models via systemic administration. The safety of systemic administration of AdIU3 was evaluated. AdCMVFasL, in which FasL was controlled by a universal cytomegalovirus (CMV) promoter, was used as a control. Results: AdIU3 enhanced FasL expression in prostate-specific antigen (PSA)/prostate-specific membrane antigen (PSMA)-positive cells but not in PSA/PMSA-negative cells. It induced apoptosis and killed PSA/PMSA-positive prostate cancer cells but spared normal human fibroblasts, hepatocytes, and negative cells. The increase in killing activity was confirmed to result in part from a bystander killing effect. Furthermore, AdIU3 was more effective than a plain PRRA in inhibiting the growth of androgen-independent prostate cancer xenografts and bone tumor formation. Importantly, systemic administration of AdIU3 resulted in undetectable toxicity, whereas the same doses of AdCMVFasL killed all mice due to multiviscera failure in 16 h. Conclusions: AdIU3 decreased the toxicity of FasL by controlling its expression with PSES, with greatly enhanced prostate cancer antitumor efficacy. The results suggested that toxic antitumor factors can be delivered safely by a PRRA.

Treating recurrent prostate cancer poses a great challenge to clinicians. Research efforts in the last decade have shown that adenoviral vector-based gene therapy is a promising approach that could expand the arsenal against prostate cancer. This maturing field is at the stage of being able to translate many preclinical discoveries into clinical practices. At this juncture, it is important to highlight the promising strategies including prostate-targeted gene expression, the use of oncolytic vectors, therapy coupled to reporter gene imaging, and combined treatment modalities. In fact, the early stages of clinical investigation employing combined, multimodal gene therapy focused on loco-regional tumor eradication and showed promising results. Clinicians and scientists should seize the momentum of progress to push forward to improve the therapeutic outcome for the patients.

Thyroid cancer affects between 10,000 and 15,000 people per year in the US. Typically, this disease can be controlled with surgical resection and radioiodide treatment. However, resistance to these conventional therapies is observed in some patients, who develop intractable anaplastic thyroid cancer (ATC), for which no effective therapies exist. Recently, a sizable fraction of undifferentiated or poorly differentiated thyroid cancers were shown to contain mutations in beta-catenin, an oncogenic protein involved in the etiology of cancers of many tissues. We developed a conditionally replicative adenovirus (named 'HILMI') which, by virtue of TCF response elements drives E1A and E1B expression, replicates specifically in cells with an active Wnt/beta-catenin pathway. We show that several thyroid cancer cell lines, derived from undifferentiated or anaplastic tissues and possessing an active Wnt/beta-catenin pathway, are susceptible to cell killing by HILMI. Furthermore, viral replication in ATC cells as xenograft tumors in nude mice was observed, and prolonged survival of mice with ATC tumors was observed following administration of the HILMI therapeutic vector. The results warrant further development of this therapeutic approach for ATC patients.

Background Osteosarcoma (OSA) is the most frequent type of primary malignant bone tumor and is apt to occur in children and young adults. Pulmonary metastasis (OSPM) is the major reason for its fatal outcome. Osteocalcin (OC) is a major noncollagenous bone protein whose expression is limited almost exclusively to bone marrow and osteotropic tumors. OC is also known to express in cell lines with bone metastasis feathers. Gene therapy strategies with the OC promoter directing the replication of adenovirus in a tumor-specific manner are a potential modality for OSPM therapy. Methods We detected OC mRNA expression by RNA in situ hybridization in OSA and OSPM samples from patients, and tested OC promoter transcriptional activity in OSA and non-OSA cell lines. Then we used a transcriptional replication-competent adenovirus, Ad-OC-E1a, to treat OSPM, and evaluated its tumor-specific replication and killing activities in vitro as well as anti-OSPM efficacy in vivo via systemic delivery. Results OC mRNA was detected in all types of OSA tissues, including OSPM tissues. The transcriptional activity of the OC promoter was much higher in a OSPM cell line SAOS-2LM7 and primary OSA cell line MG63 than in non-OSA cell lines, including cell lines from breast cancer, colon cancer, and liver cancer. Ad-OC-E1a expressed E1a protein only in MG63 and SAOS-2LM7, which indicated that adenovirus E1a was under strict control by the OC promoter. Ad-OC-E1a demonstrated killing and viral replication activity close to wild-type adenovirus levels in MG63 and SAOS-2LM7, but the killing and viral replication activities were attenuated significantly in cells expressing low OC transcriptional activity. To test whether Ad-OC-E1a could be used to target human OSPM in vivo, SAOS-2LM7 pulmonary metastasis models in nude mice were induced and treated by tail-vein injection with Ad-OC-E1a. Compared to tumor nodules in the lung in groups treated with PBS or control virus, the quantity of metastasized tumor nodules decreased significantly. Adenovirus-infected cells were stained immunohistochemically only inside and around the OSPM nodules but spared normal lung tissue and other organs. Conclusions These data demonstrated that OC promoter could direct adenovirus replication by controlling the E1a gene to target human OSPM in a tumor-specific manner, providing an efficient tool to develop a feasible therapeutic modality for OSPM. Copyright © 2006 John Wiley & Sons, Ltd.

Angiogenesis is essential for prostate cancer development and metastasis. Antiangiogenic therapy targeting tumor neovasculature, therefore, represents a promising approach for prostate cancer treatment. We hypothesized that adenoviral-mediated delivery of a combination of antiangiogenic factors might have an enhanced antitumor response. We developed the adenoviral vectors Ad-hEndo-angio, expressing a unique, chimeric human endostatin–angiostatin fusion protein, and Ad-sTie2, expressing a soluble form of endothelium-specific receptor tyrosine kinase Tie2. Matrigel angiogenesis assays using Ad-hEndo-angio revealed significant inhibition of tubular network formation and endothelial sprouting compared to Ad-sTie2. In vivo studies in a bilateral PC-3 tumor xenograft model following either intratumoral or systemic administration of Ad-hEndo-angio led to enhanced tumor growth suppression compared to Ad-sTie2. A novel finding is that an intratumoral, combination therapy employing one-half the dose of Ad-hEndo-angio as well as Ad-sTie2 led to a complete regression of the injected, as well as the contralateral uninjected, tumor and prolonged the tumor-free survival in 80% of the animals. In addition, a novel, real-time, intravital imaging modality was used to monitor antiangiogenic responses following adenoviral-mediated gene transfer. These results suggest that a combinatorial antiangiogenic gene therapy approach involving Ad-hEndo-angio and Ad-sTie2 could become a novel form of treatment for localized human prostate cancer.

The breast-specific antigen α-lactalbumin is expressed in >60% of breast cancer tissues. To evaluate the effect of gene therapy for breast cancer by controlling adenovirus replication with human α-lactalbumin promoter, we investigated the activity of a 762-bp human α-lactalbumin promoter. α-Lactalbumin promoter showed significantly higher activity in MDA-MB-435S and T47D breast cancer cells than in normal breast cell lines or other tumor cell lines. We then developed two novel breast cancer–restricted replicative adenoviruses, AdALAE1a and AdE1aALAE1b. In AdALAE1a, expression of adenoviral E1a gene is under the control of α-lactalbumin promoter, and in AdE1aALAE1b, expression of both E1a and E1b genes is under the control of a single α-lactalbumin promoter. Both breast cancer–restricted replicative adenoviruses showed viral replication efficiency and tumor cell-killing capability similar to wild-type adenovirus in MDA-MB-435S and T47D cells. The replication efficiency and tumor cell-killing capability of both viruses were attenuated significantly in cells that did not support α-lactalbumin promoter. AdE1aALAE1b showed better breast cancer–restricted replication than AdALAE1a, suggesting that a transcriptional targeting modality with α-lactalbumin promoter controlling both E1a and E1b gene expression is superior to α-lactalbumin promoter controlling only E1a gene expression. Importantly, we found that AdE1aALAE1b could be used to target hormone-independent breast tumors in vivo by inhibiting the growth of MDA-MB-435S s.c. tumors. These data showed that α-lactalbumin promoter could regulate the replication of adenovirus to target hormone-independent breast cancers, suggesting that α-lactalbumin promoter can be used to develop a novel therapeutic modality for hormone-independent breast cancer. [Mol Cancer Ther 2005;4(12):1850–9]

An improved total synthesis of [18F]FHPG starting from 1,3‐dibenzyloxy‐2‐propanol and guanine has been developed. [18F]FHPG was prepared by nucleophilic substitution of the appropriate precursor with [18F]KF/Kryptofix 2.2.2 followed by a quick deprotection reaction and purification with a simplified Silica Sep‐Pak solid‐phase extraction (SPE) method in 10–15% radiochemical yield, and 70 min synthesis time from end of bombardment (EOB).

An improved total synthesis of [18F]FHBG starting from triethyl‐1,1,2‐ethanetricarboxylate and 2‐amino‐6‐chloropurine is reported. [18F]FHBG was prepared by nucleophilic substitution of the appropriate precursor with [18F]KF/Kryptofix 2.2.2 followed by a quick deprotection reaction and purification with a simplified Silica Sep‐Pak solid‐phase extraction (SPE) method in 20–25% radiochemical yield.

Prostate cancer is the second most commonly diagnosed cancer in men and accounts for significant mortality and morbidity in the United States. Initially androgen-dependent, prostate cancer ultimately becomes androgen-independent, which makes the disease extremely difficult to cure. In this study, we examined the use of conditionally replication-competent adenovirus for the treatment of hormone-independent prostate cancer. We utilized PSME, an enhancer element for prostate-specific PSMA expression, to control viral E1A protein expression and achieve exclusive virus replication in prostate. Western blotting confirmed that PSME mediated high E1A protein expression in PSMA-positive, androgen-independent prostate cancer cells (C4-2 and CWR22rv), but was much less active in PSMA-negative cancer cells (PC-3 and A549). Consistent with E1A protein expression, the recombinant adenovirus Ad5-PSME-E1a replicated in C4-2 and CWR22rv almost as efficiently as wild type with low levels of androgen, but its replication was significantly attenuated in PSMA-negative cells. In the in vitro killing assay, Ad5-PSME-E1a lysed all C4-2 and CWR22rv cells 5 days after infection, with minimal effect on PSMA-negative cells. In addition, injections of 1.7 x 10(8) plaque-forming units in a CWR22rv xenograft model in nude mice induced significant tumor growth delay, with a substantial necrotic area. These studies suggest that PSME-driven replication-competent adenovirus may be a new therapeutic modality for prostate cancer patients after hormone ablation therapy.

Objectives To develop a new toxic gene therapy using the tissue-specific human chorionic gonadotropin-beta (hCG-β) promoter for testicular cancer. Although most patients presenting with disseminated testicular tumor are cured through the use of chemotherapy with or without surgery, those patients with relapse after initial therapy present a difficult clinical problem. The serum tumor marker hCG-β is frequently elevated in patients with testicular cancer, and the pretreatment and post-treatment levels of serum hCG-β are highly predictive of treatment outcome. Methods Human testicular embryonal carcinoma cell line, NEC 8, a human prostate cancer cell line, PC-3, and a human bladder cancer cell line, WH, were used in this study. A transient expression experiment was used to analyze the activity of a 729-bp hCG-β promoter in all three cell lines. A recombinant adenovirus carrying thymidine kinase (Ad-hCG-β-TK) under control of the hCG-β promoter was generated. The tissue-specific activity of Ad-hCG-β-TK was tested in vitro and in vivo. Results The hCG-β promoter had significantly greater activity in the hCG-β-producing cell line (NEC 8) than in the non-hCG-β-producing cell lines (PC-3 and WH). In vitro, Ad-hCG-β-TK with acyclovir significantly inhibited NEC 8 growth but not PC-3 or WH cell growth. In vivo, Ad-hCG-β-TK with acyclovir significantly inhibited NEC 8 subcutaneous tumor growth in nude mice. Conclusions In this study, we explored the possibility of developing a new therapeutic agent to target and induce the killing of testicular germ cell tumor selectively by using tissue-specific hCG-β promoters.

EphA2 is a transmembrane receptor tyrosine kinase that is overexpressed in many carcinomas. Specific targeting of EphA2 with monoclonal antibodies is sufficient to inhibit the growth, migration and invasiveness of aggressive cancers in animal models. Using immunohistochemical analyses, we measured the expression of EphA2 in prostatic adenocarcinoma, high-grade prostatic intraepithelial neoplasia, and adjacent benign prostate tissue from ninety-three radical prostatectomy specimens. These results were related to multiple clinical and pathologicalcharacteristics. The fraction of cells staining positively with EphA2 in benign prostatic epithelium (mean, 12%) was significantly lower than that in high-grade prostatic intraepithelial neoplasia (mean, 67%, P < 0.001) and prostatic adenocarcinoma (mean, 85%, P < 0.001). Moreover, the intensity of EphA2 immunoreactivity in prostatic adenocarcinoma was significantly higher than in benign prostatic tissue (P < 0.001) or high-grade prostatic intraepithelial neoplasia (P < 0.001). Benign prostatic epithelium showed weak or no immunoreactivity for EphA2 in all cases examined. Whereas EphA2 immunoreactivity related to neoplastic transformation, it did not correlate with other clinical and pathological parameters examined. Our data suggest that EphA2 levels increase as prostatic epithelial cells progress toward a more aggressive phenotype. Progressively higher levels of EphA2 in high-grade prostatic intraepithelial neoplasia and prostatic carcinoma are consistent with recent evidence that EphA2 functions as a powerful oncogene. Moreover, the presence of high levels of EphA2 in these cells suggests opportunities for prostate cancer prevention and treatment.

The mechanism whereby lovastatin can counteract steroid-induced osteonecrosis and osteoporosis is poorly understood. We assessed the effect of lovastatin on a multipotential cell line, D1, which is capable of differentiating into either the osteoblast or the adipocyte lineage. The expression of bone cell and fat cell transcription factors Cbfa1/Runx2 and PPARgamma2, respectively, were determined. 422aP2 gene expression was analyzed. Osteocalcin promoter activity was measured by cotransfecting the cells with the phOC-luc and pSV beta-Gal plasmids. Lovastatin enhanced osteoblast differentiation as assessed by a 1.8x increase in expression of Cbfa1/Runx2 and by a 5x increase in osteocalcin promoter activity. Expression of PPARgamma2 was decreased by 60%. By enhancing osteoblast gene expression and by inhibiting adipogenesis, lovastatin may shunt uncommitted osteoprogenitor cells in marrow from the adipocytic to the osteoblastic differentiation pathway. Future evaluation of lovastatin and other lipid-lowering drugs will help determine their potential as therapeutic agents for osteonecrosis and osteoporosis.

Osteocalcin (OC), a major noncollagenous bone matrix protein, is expressed prevalently in prostate cancer epithelial cells, adjacent fibromuscular stromal cells, and osteoblasts in locally recurrent prostate cancer and prostate cancer bone metastasis [Matsubara, S., Wada, Y., Gardner, T.A., Egawa, M., Park, M.S., Hsieh, C.L., Zhau, H.E., Kao, C., Kamidono, S., Gillenwater, J.Y., and Chung, L.W. (2001). Cancer Res. 61, 6012-6019]. We constructed an adenovirus vector carrying osteocalcin promoter-driven herpes simplex virus thymidine kinase (Ad-OC-hsv-TK) to cotarget prostate cancer cells and their surrounding stromal cells. A phase I dose escalation clinical trial of the intralesional administration of Ad-OC-hsv-TK followed by oral valacyclovir was conducted at the University of Virginia (Charlottesville, VA) in 11 men with localized recurrent and metastatic hormone-refractory prostate cancer (2 local recurrent, 5 osseous metastasis, and 4 lymph node metastasis) in order to determine the usefulness of this vector for the palliation of androgen-independent prostate cancer metastasis. This is the first clinical trial in which therapeutic adenoviruses are injected directly into prostate cancer lymph node and bone metastasis. Results show that (1). all patients tolerated this therapy with no serious adverse events; (2). local cell death was observed in treated lesions in seven patients (63.6%) as assessed by TUNEL assay, and histomorphological change (mediation of fibrosis) was detected in all posttreated specimens; (3). one patient showed stabilization of the treated lesion for 317 days with no alternative therapy. Of the two patients who complained of tumor-associated symptoms before the treatment, one patient with bone pain had resolution of pain, although significant remission of treated lesions was not observed by image examination; (4). CD8-positive T cells were predominant compared with CD4-positive T cells, B cells (L26 positive), and natural killer cells (CD56 positive) in posttreated tissue specimens; (5). levels of HSV TK gene transduction correlated well with coxsackie-adenovirus receptor expression but less well with the titers of adenovirus injected; and (6). intrinsic OC expression and the efficiency of HSV TK gene transduction affected the levels of HSV TK protein expression in clinical specimens. Our data suggest that this form of gene therapy requires further development for the treatment of androgen-independent prostate cancer metastasis although histopathological and immunohistochemical evidence of apoptosis was observed in the specimens treated. Further studies including the development of viral delivery will enhance the efficacy of Ad-OC-hsv-TK.

The expression of prostate-specific membrane antigen (PSMA) and prostate-specific antigen (PSA), two well characterized marker proteins, remains highly active in the hormone refractory stage of prostate cancer. In this study, an artificial chimeric enhancer (PSES) composed of two modified regulatory elements controlling the expression of PSA and PSMA genes was tested for its promoter activity and tissue specificity using the reporter system. As a result, this novel PSES promoter remained silent in PSA- and PSMA-negative prostate and non-prostate cancer cell lines, but mediated high levels of luciferase in PSA- and PSMA-expressing prostate cancer cell lines in the presence and absence of androgen. To determine whether PSES could be used for in vivo gene therapy of prostate cancer, a recombinant adenovirus, Ad-PSES-luc, was constructed. Luciferase activity in prostate cancer cell lines mediated by Ad-PSES-luc was 400- to 1000-fold higher than in several other non-prostate cell lines, suggesting the high tissue-specificity of the PSES promoter in an adenoviral vector. Finally, recombinant virus Ad-PSES-luc was injected into mice to evaluate the tissue-discriminatory promoter activity in an experimental animal. Unlike Ad-CMV-luc, the luciferase activity from systemic injection of Ad-PSES-luc was fairly low in all major organs. However, when injected into prostate, Ad-PSES-luc drove high luciferase activity almost exclusively in prostate and not in other tissues. Our results demonstrated the potential use of PSES for the treatment of androgen-independent prostate cancer patients.

BACKGROUND Recent data suggest that anti-tumor activities of interleukin-12 (IL-12) involve the induction of apoptosis. Fas (APO-1/CD95) is a type I membrane protein that is capable of initiating an apoptosis signaling pathway when bound to its ligand (FasL). We undertook this study to test the hypothesis that Fas-FasL–mediated apoptosis plays a role in IL-12–induced tumor regression. METHODS An mIL-12 expression vector driven by cytomegalovirus promoter was used to express murine IL-12 cDNA in the RM-9 murine prostate carcinoma cell line. Control RM-9 cells and RM-9 cells stably transfected with IL-12 gene (RM-9-IL12) were inoculated subcutaneously in 4- to 6-week-old male C57BL/J6 mice. Tumor size was measured every 3 days. Western blot and immunohistochemical assays were used to evaluate Fas and FasL protein expression. In situ fluorescent end labeling was used to label apoptotic cells. RESULTS IL-12–expressing RM-9 prostate carcinoma cells transplanted into C57BL/J6 mice grew more slowly than control RM-9 cells and vector control RM-9-Luc cells. The average survival time of the RM-9-IL12 mice was longer than 53 days, whereas the mean survival for mice transplanted with control RM-9 cells was only 16 days. Apoptotic cells were more numerous in RM-9-IL12 tumors: 10.3% vs. 1.5% in control (P = 0.001). Fas and FasL proteins were increased approximately twofold in the RM-9-IL12 tumors compared with the RM-9 control tumors as determined by Western blot and immunohistochemical analyses (P

Background: Patients with high-grade transitional-cell carcinoma (TCC) of the bladder frequently experience recurrence and progress and have a low response rate to chemotherapy in metastatic TCC. In this study, we evaluated the feasibility and long-term efficacy of suicide-gene therapy using adenovirus (Ad)-mediated herpes simplex virus thymidine kinase gene (HSV-TK) and prodrug ganciclovir (GCV) as a potential therapeutic approach in murine-orthotopic models of TCC. Methods: A replication defective adenoviral vectors containing toxic HSV-TK gene under the transcriptional control of RSV (Rous sarcoma virus) promoter (Ad-RSV-TK) was used. Orthotopic bladder TCC was established with 1 × 106 murine (MBT-2) TCC cells in syngenic C3H/He female mice. Intratumoral injection of Ad-RSV-TK in combination with GCV (20 mg/kg body weight/day i.p. b.i.d. × 7 days) was administered in vivo for the determination of treatment efficacy and long-term host survival in separate controlled experiments. Results:In vivo experiments demonstrated greater than three-fold reductions in MBT-2 tumor growth for the animals treated with Ad-RSV-TK (5 × 108 plaque forming units (pfu)/GCV therapy (P

Gene therapy has been used to target prostate cancer with excellent pre-clinical efficacy but limited clinical efficacy. The concept of delivering genetic material to prostate cancer cells to alter their phenotype and ultimately their behavior has been demonstrated in the laboratory over the last decade. Translating those pre-clinical findings into novel therapies for prostate cancer has been difficult. The stigma of gene therapy and the aggressive regulation of clinical trials involving transfer of genetic material to patients are two major impediments to clinical successes in gene therapy. This review hopes to provide a snapshot of prior gene transfer protocol findings and forecast the exciting future directions investigators are heading.

Background: Our previous work showed a significant reduction of tumor growth, macrophage infiltration, circulating IGF-1, and mTOR activation with low protein diet in a patient derived xenograft model of prostate cancer. The evolutionarily conserved, nutrient sensing, mTOR pathway plays a central role in both development of advanced stage prostate cancer and immune responsiveness. This study presents novel data on the impact of dietary protein modification on the function of the host immune system in response to prostate cancer and immunotherapy. Methods: Our In vitro studies utilized bone marrow or tumor derived (RP-B6 Myc) macrophages. In vivo studies utilized the recently characterized RP-B6 Myc model. Mice were fed ad libitum control or methionine restricted diets for four weeks prior to S.C. implantation with ~1mm2 tumor pieces. Treatment of survivin peptide vaccine (1mg/ml S.C. 1 X week) and anti-PD-1 (20mg/kg I.P. 2 X week) began at ~50mm2 tumor size. Tumor volumes were blindly recorded 2 X week. End point analyses include: tumor weight, flow cytometric analysis, proteomic profiler analyses, and microbiome analyses from each diet and treatment group. Results: We show here that while methionine restriction (MR) has little impact on our RP-B6 Myc prostate cancer cell line, it does yield a significant alteration in both the polarization and function of M1 and M2 macrophages. In the in vitro MR conditions, we observed significantly enhanced polarization of M1 macrophages and reduced polarization of M2 macrophages. Functional analysis revealed increased tumoricidal activity of both M1, ‘antitumor’, and M2, ‘pro-tumor,’ macrophages suggesting a flip in M2 function from tumor-promoting to tumoricidal. Further analysis of the released cytokines in MR media conditions yielded significant increase of antitumor cytokines & chemokines, such as IL-12, IL-27, CXCL9, CXCL10, CXCL11, CCL2, CCL4, and TNF-alpha, a double-edged sword which in our system correlates with decreased cancer cell viability upon co-culture with amino acid restricted M1 and M2 macrophages. Our preliminary results show dietary MR yielding a significant inhibition of prostate cancer growth in the RP-B6-Myc model and our ongoing study with survivin peptide vaccine and anti-PD-1 immunotherapies will be available to present in the conference. Conclusions: Our data suggest that restricting methionine is sufficient to alter both the polarization and tumoricidal function of macrophages. Our preliminarily results show that restricted dietary methionine is able to inhibit prostate cancer growth, modify the host immune response and better inhibit prostate cancer growth alone or in combination with immunotherapy. These results provide a strong basis to consider diet restriction as a means to limit cancer growth targeting tumor immune system and potentially to enhance cancer patient responses to immunotherapy. Citation Format: Ashley R. Orillion, Sreenivasulu Chintala, Remi Adelaiye-Ogala, Li Shen, Nur Damayanti, May Elbanna, Sreevani Arisa, Bennett Elzey, Chinghai Kao, Luigi Fontana, Roberto Pili. Methionine restriction increases macrophage tumoricidal activity and significantly inhibits prostate cancer growth [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 250. doi:10.1158/1538-7445.AM2017-250