Differential expression of CCR8 in tumors versus normal tissue allows specific depletion of tumor-infiltrating T regulatory cells by GS-1811, a novel Fc-optimized anti-CCR8 antibody

The presence of T regulatory (Treg) cells in the tumor microenvironment is associated with poor prognosis and resistance to therapies aimed at reactivating anti-tumor immune responses. Therefore, depletion of tumor-infiltrating Tregs is a potential approach to overcome resistance to immunotherapy. However, identifying Treg-specific targets to drive such selective depletion is challenging. CCR8 has recently emerged as one of these potential targets. Here, we describe GS-1811, a novel therapeutic monoclonal antibody that specifically binds to human CCR8 and is designed to selectively deplete tumor-infiltrating Tregs. We validate previous findings showing restricted expression of CCR8 on tumor Tregs, and precisely quantify CCR8 receptor densities on tumor and normal tissue T cell subsets, demonstrating a window for selective depletion of Tregs in the tumor. Importantly, we show that GS-1811 depleting activity is limited to cells expressing CCR8 at levels comparable to tumor-infiltrating Tregs. Targeting CCR8 in mouse tumor models results in robust anti-tumor efficacy, which is dependent on Treg depleting activity, and synergizes with PD-1 inhibition to promote anti-tumor responses in PD-1 resistant models. Our data support clinical development of GS-1811 to target CCR8 in cancer and drive tumor Treg depletion in order to promote anti-tumor immunity.

The Society for Immunotherapy of Cancer statement on best practices for multiplex immunohistochemistry (IHC) and immunofluorescence (IF) staining and validation

OBJECTIVES

The interaction between the immune system and tumor cells is an important feature for the prognosis and treatment of cancer. Multiplex immunohistochemistry (mIHC) and multiplex immunofluorescence (mIF) analyses are emerging technologies that can be used to help quantify immune cell subsets, their functional state, and their spatial arrangement within the tumor microenvironment.

METHODS

The Society for Immunotherapy of Cancer (SITC) convened a task force of pathologists and laboratory leaders from academic centers as well as experts from pharmaceutical and diagnostic companies to develop best practice guidelines for the optimization and validation of mIHC/mIF assays across platforms.

RESULTS

Representative outputs and the advantages and disadvantages of mIHC/mIF approaches, such as multiplexed chromogenic IHC, multiplexed immunohistochemical consecutive staining on single slide, mIF (including multispectral approaches), tissue-based mass spectrometry, and digital spatial profiling are discussed.

CONCLUSIONS

mIHC/mIF technologies are becoming standard tools for biomarker studies and are likely to enter routine clinical practice in the near future. Careful assay optimization and validation will help ensure outputs are robust and comparable across laboratories as well as potentially across mIHC/mIF platforms. Quantitative image analysis of mIHC/mIF output and data management considerations will be addressed in a complementary manuscript from this task force.

Abstract 5007: Preclinical evaluation of JTX-8064, an anti-LILRB2 antagonist antibody, for reprogramming tumor-associated macrophages

Introduction: Jounce has generated cell type-specific gene signatures as a means of probing The Cancer Genome Atlas and other large datasets to identify targets that may be important immune checkpoints. Using a tumor-associated macrophage (TAM) gene signature, we have found a strong correlation and coherence between TAMs and LILRB2 (leukocyte immunoglobulin like receptor B2; ILT4) across multiple tumors types. LILRB2 is a myeloid cell surface receptor containing four extracellular immunoglobulin domains, a transmembrane domain, and three cytoplasmic immunoreceptor tyrosine-based inhibitory motifs (ITIMs). Ligation of LILRB2 on myeloid cells, via its endogenous ligands (classical MHC I molecules [e.g. HLA-A, HLA-B] and non-classical MHC I molecules [e.g. HLA-G]), provides a negative signal that inhibits stimulation of an immune response. HLA-G is recognized as an important immunosuppressive molecule playing a role in maternal-fetal tolerance and being overexpressed in cancer - often associated with advanced disease stage and poor prognosis. As tumor-associated macrophages are known to suppress the anti-cancer immune response, these findings provide rationale for targeting LILRB2.

Methods and Results: We have generated a panel of monoclonal antibodies that bind specifically to LILRB2, but not other LILR family members, and can block binding of LILRB2 to MHC I molecules (i.e. HLA-A and HLA-G). In vitro differentiated monocyte-derived macrophages (MDMs) cultured for 24h in the presence of anti-LILRB2 antibodies and lipopolysaccharide (LPS) show polarization toward a more inflammatory phenotype - secreting higher levels of TNF-α and IL-6 with decreased amounts of IL-10 and CCL2 as compared to an isotype control antibody. NanoString mRNA analysis revealed that, in the absence of LPS or any additional stimuli, MDMs cultured with anti-LILRB2 antibodies showed gene changes consistent with inflammatory or M1-like polarization of macrophages. Anti-LILRB2 antibodies were also evaluated in human tumor histoculture and induced pharmacodynamic responses consistent with macrophage and T cell activation in a variety of tumor types. While mice do not express LILRB2 specifically, they do express a LILRB-like molecule known as Pirb. Mice that are deficient in Pirb display resistance to mouse colon 38 (MC-38) tumor growth suggesting this pathway functions as immune checkpoint in cancer.

Conclusions: Based on these preclinical data, JTX-8064, a high affinity LILRB2-specific humanized antagonist monoclonal antibody, is being developed as an immunotherapeutic to reprogram suppressive macrophages within the tumor microenvironment.

Citation Format: Heather Cohen, Yasmin Hashambhoy-Ramsay, Lauren R. Pepper, Jeffrey Y. Smith, Margaret Willer, Kevin Guay, Vikki Spaulding, Kristin O'Malley, Monica Gostissa, Abha Dhaneshwar, Edward C. Stack, Alessandro Mora, Donald R. Shaffer. Preclinical evaluation of JTX-8064, an anti-LILRB2 antagonist antibody, for reprogramming tumor-associated macrophages [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 5007.

Fatty Acid Synthase and Acetyl-CoA Carboxylase Are Expressed in Nodal Metastatic Melanoma But Not in Benign Intracapsular Nodal Nevi

BACKGROUND

Melanoma is a potentially lethal form of skin cancer for which the current standard therapy is complete surgical removal of the primary tumor followed by sentinel lymph node biopsy when indicated. Histologic identification of metastatic melanoma in a sentinel node has significant prognostic and therapeutic implications, routinely guiding further surgical management with regional lymphadenectomy. While melanocytes in a lymph node can be identified by routine histopathologic and immunohistochemical examination, the distinction between nodal nevus cells and melanoma can be morphologically problematic. Previous studies have shown that malignant melanoma can over-express metabolic genes such as fatty acid synthase (FASN) and acetyl-CoA carboxylase (ACC). This immunohistochemical study aims to compare the utility of FASN and ACC in differentiating sentinel lymph nodes with metastatic melanomas from those with benign nodal nevi in patients with cutaneous melanoma.

MATERIALS AND METHODS

Using antibodies against FASN and ACC, 13 sentinel lymph nodes from 13 patients with metastatic melanoma and 14 lymph nodes harboring benign intracapsular nevi from 14 patients with cutaneous malignant melanoma were examined. A diagnosis of nodal melanoma was based on cytologic atypia and histologic comparison with the primary melanoma. All nodal nevi were intracapsular and not trabecular. Immunohistochemistry for Melan-A, S100, human melanoma black 45 (HMB45), FASN, and ACC were performed. The percentage of melanocytes staining with HMB45, FASN, and ACC was determined and graded in 25% increments; staining intensity was graded as weak, moderate, or strong.

RESULTS

All metastatic melanomas tested had at least 25% tumor cell staining for both FASN and ACC. Greater than 75% of the tumor cells stained with FAS in 7/13 cases and for ACC in 5/12 cases. Intensity of staining was variable; strong staining for FASN and ACC was observed in 69% and 50% of metastatic melanoma, respectively. HMB45 was negative in 40% of nodal melanoma cases all of which stained with FASN and ACC. Capsular nevi were uniformly negative for FASN, ACC, and HMB45 immunoreactivity.

CONCLUSIONS

All metastatic melanoma cases involving sentinel lymph nodes were positive for FASN and ACC while no staining was observed in intracapsular nevi. These findings suggest that FASN and ACC could be used as valuable ancillary stains in the distinction between nodal nevi and metastatic melanoma.

Quantitative Analysis of Immune Infiltrates in Primary Melanoma

Novel methods to analyze the tumor microenvironment (TME) are urgently needed to stratify melanoma patients for adjuvant immunotherapy. Tumor-infiltrating lymphocyte (TIL) analysis, by conventional pathologic methods, is predictive but is insufficiently precise for clinical application. Quantitative multiplex immunofluorescence (qmIF) allows for evaluation of the TME using multiparameter phenotyping, tissue segmentation, and quantitative spatial analysis (qSA). Given that CD3⁺CD8⁺ cytotoxic lymphocytes (CTLs) promote antitumor immunity, whereas CD68⁺ macrophages impair immunity, we hypothesized that quantification and spatial analysis of macrophages and CTLs would correlate with clinical outcome. We applied qmIF to 104 primary stage II to III melanoma tumors and found that CTLs were closer in proximity to activated (CD68⁺HLA-DR⁺) macrophages than nonactivated (CD68⁺HLA-DR^-) macrophages (P < 0.0001). CTLs were further in proximity from proliferating SOX10⁺ melanoma cells than nonproliferating ones (P < 0.0001). In 64 patients with known cause of death, we found that high CTL and low macrophage density in the stroma (P = 0.0038 and P = 0.0006, respectively) correlated with disease-specific survival (DSS), but the correlation was less significant for CTL and macrophage density in the tumor (P = 0.0147 and P = 0.0426, respectively). DSS correlation was strongest for stromal HLA-DR⁺ CTLs (P = 0.0005). CTL distance to HLA-DR^- macrophages associated with poor DSS (P = 0.0016), whereas distance to Ki67^- tumor cells associated inversely with DSS (P = 0.0006). A low CTL/macrophage ratio in the stroma conferred a hazard ratio (HR) of 3.719 for death from melanoma and correlated with shortened overall survival (OS) in the complete 104 patient cohort by Cox analysis (P = 0.009) and merits further development as a biomarker for clinical application. Cancer Immunol Res; 6(4); 481-93. ©2018 AACR.

MYC Overexpression at the Protein and mRNA Level and Cancer Outcomes among Men Treated with Radical Prostatectomy for Prostate Cancer

Background: The proto-oncogene MYC is implicated in prostate cancer progression. Whether MYC tumor expression at the protein or mRNA level is associated with poorer prognosis has not been well studied.Methods: We conducted a cohort study including 634 men from the Physicians' Health Study and Health Professionals Follow-up Study treated with radical prostatectomy for prostate cancer in 1983-2004 and followed up for a median of 13.7 years. MYC protein expression was evaluated using IHC, and we used Cox regression to calculate HRs and 95% confidence intervals (CIs) of its association with lethal prostate cancer (distant metastases/prostate cancer-related death). We assessed the association between MYC mRNA expression and lethal prostate cancer in a case-control study, including 113 lethal cases and 291 indolent controls.Results: MYC nuclear protein expression was present in 97% of tumors. MYC protein expression was positively correlated with tumor proliferation rate (r = 0.37; P < 0.001) and negatively correlated with apoptotic count (r = -0.17; P < 0.001). There were no significant associations between MYC protein expression and stage, grade, or PSA level at diagnosis. The multivariable HR for lethal prostate cancer among men in the top versus bottom quartile of MYC protein expression was 1.09 (95% CI, 0.50-2.35). There was no significant association between MYC mRNA expression and lethal prostate cancer.Conclusions: Neither MYC protein overexpression nor MYC mRNA overexpression are strong prognostic markers in men treated with radical prostatectomy for prostate cancer.Impact: This is the largest study to examine the prognostic role of MYC protein and mRNA expression in prostate cancer. Cancer Epidemiol Biomarkers Prev; 27(2); 201-7. ©2017 AACR.

Abstract 1671: Characterization of the immune landscape in stage II-III melanoma using qIF

Background: The tumor microenvironment plays a crucial role in cancer progression, often supporting immune evasion. This is of particular importance in melanoma, where immune checkpoint therapies have resulted in significant clinical benefit, yet only in a subset of melanoma patients respond. Precise biomarkers are urgently needed to characterize the tumor immune micro-environment, both for prognostication and to predict the benefit of immuno-therapeutic intervention. HLA-DR on tumor cells and Ki67 on cytotoxic (CD8+) T cells have been proposed as biomarkers of anti-PD1 activity. Quantitative immunofluorescence (qIF) allows for automated quantitation of phenotypes and spatial distributions of immune cell populations within formalin fixed paraffin embedded (FFPE) tissues.

Methods: To characterize the tumor immune microenvironment, we screened databases at the Herbert Irving Cancer Center (HICC) at Columbia University for early stage melanoma patients with documented clinical follow up. We identified a preliminary population of 40 stage II-III melanoma patients diagnosed between 2000 and 2012. Clinical follow up was available on 21 patients, 12 of whom were alive with no evidence of recurrence, 1 who died of another malignancy, and 8 who died of melanoma. 19 patients had more than 24 months of survival information available but no detailed clinical information. 5µm slides from either primary biopsy or subsequent wide local excision procedure were stained using qIF for DAPI, CD3, CD8, CD68, SOX10, HLA-DR and Ki67. Cell phenotypes within representative fields selected by a trained dermatopathologist (BH), were visualized using multispectral imaging, and analysis of spatial distribution of cells were analyzed using inForm image analysis software (Perkin Elmer), and Spotfire software (TIBCO).

Results: We were able to quantify and identify coordinates for multiple immune cell subsets in melanoma tissues. In 21 patients with clinical follow up, we found that higher densities of CD3+CD8+ T cells in tumor and stroma trended towards correlation with non-recurrence. In addition, CD68+HLA-DR- predicts poor prognosis (p&lt;0.05), whether in tumor or stroma. Assessment of spatial distribution across all 40 tumors demonstrated that CD3+CD8+ cells are closer to CD68+ cells and Sox10+ tumor cells when they express HLA-DR (p&lt;0.001). Conversely, CD3+CD8+ cells are significantly farther from tumor cells when they express Ki-67, (p&lt;0.001). Among patients with clinical follow up, CD3+CD8+ cells were closer to CD68+HLA-DR- cells in recurrent patients (p &lt; 0.05).

Conclusion: Using qIF imaging and analysis we find that density and spatial relationships of immune cell subsets correlates with recurrence status. qIF may offer the potential for the development of prognostic biomarkers in stage II/III melanoma.

Citation Format: Robyn Gartrell, Douglas Marks, Edward C. Stack, Yan Lu, Thomas D. Hart, Camille Gerard, Camden Esancy, Dan Tong Jia, Paul Armenta, Daisuke Izaki, Danielle Davari, Ashley White-Stern, Zoe Blake, Yichun Fu, Basil Horst, Yvonne Saenger. Characterization of the immune landscape in stage II-III melanoma using qIF [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 1671. doi:10.1158/1538-7445.AM2017-1671

Novel technologies and emerging biomarkers for personalized cancer immunotherapy

The culmination of over a century's work to understand the role of the immune system in tumor control has led to the recent advances in cancer immunotherapies that have resulted in durable clinical responses in patients with a variety of malignancies. Cancer immunotherapies are rapidly changing traditional treatment paradigms and expanding the therapeutic landscape for cancer patients. However, despite the current success of these therapies, not all patients respond to immunotherapy and even those that do often experience toxicities. Thus, there is a growing need to identify predictive and prognostic biomarkers that enhance our understanding of the mechanisms underlying the complex interactions between the immune system and cancer. Therefore, the Society for Immunotherapy of Cancer (SITC) reconvened an Immune Biomarkers Task Force to review state of the art technologies, identify current hurdlers, and make recommendations for the field. As a product of this task force, Working Group 2 (WG2), consisting of international experts from academia and industry, assembled to identify and discuss promising technologies for biomarker discovery and validation. Thus, this WG2 consensus paper will focus on the current status of emerging biomarkers for immune checkpoint blockade therapy and discuss novel technologies as well as high dimensional data analysis platforms that will be pivotal for future biomarker research. In addition, this paper will include a brief overview of the current challenges with recommendations for future biomarker discovery.

Novel technologies and emerging biomarkers for personalized cancer immunotherapy

The culmination of over a century’s work to understand the role of the immune system in tumor control has led to the recent advances in cancer immunotherapies that have resulted in durable clinical responses in patients with a variety of malignancies. Cancer immunotherapies are rapidly changing traditional treatment paradigms and expanding the therapeutic landscape for cancer patients. However, despite the current success of these therapies, not all patients respond to immunotherapy and even those that do often experience toxicities. Thus, there is a growing need to identify predictive and prognostic biomarkers that enhance our understanding of the mechanisms underlying the complex interactions between the immune system and cancer. Therefore, the Society for Immunotherapy of Cancer (SITC) reconvened an Immune Biomarkers Task Force to review state of the art technologies, identify current hurdlers, and make recommendations for the field. As a product of this task force, Working Group 2 (WG2), consisting of international experts from academia and industry, assembled to identify and discuss promising technologies for biomarker discovery and validation. Thus, this WG2 consensus paper will focus on the current status of emerging biomarkers for immune checkpoint blockade therapy and discuss novel technologies as well as high dimensional data analysis platforms that will be pivotal for future biomarker research. In addition, this paper will include a brief overview of the current challenges with recommendations for future biomarker discovery.

Expression Levels of DNA Damage Repair Proteins Are Associated With Overall Survival in Platinum-Treated Advanced Urothelial Carcinoma

BACKGROUND

Combination platinum chemotherapy is standard first-line therapy for metastatic urothelial carcinoma (mUC). Defining the platinum response biomarkers for patients with mUC could establish personalize medicine and provide insights into mUC biology. Although DNA repair mechanisms have been hypothesized to mediate the platinum response, we sought to analyze whether increased expression of DNA damage genes would correlate with worse overall survival (OS) in patients with mUC.

PATIENTS AND METHODS

We retrospectively identified a clinically annotated cohort of patients with mUC, who had been treated with first-line platinum combination chemotherapy. A tissue microarray was constructed from formalin-fixed paraffin-embedded tissue from the primary tumor before treatment. Immunohistochemical analysis of the following DNA repair proteins was performed: ERCC1, RAD51, BRCA1/2, PAR, and PARP-1. Nuclear and cytoplasmic expression was analyzed using multispectral imaging. Nuclear staining was used for the survival analysis. Cox regression analysis was used to evaluate the associations between the percentage of positive nuclear staining and OS in multivariable analysis, controlling for known prognostic variables.

RESULTS

In a cohort of 104 patients with mUC, a greater percentage of nuclear staining of ERCC1 (hazard ratio [HR], 2.7; 95% confidence interval [CI], 1.5-4.9; P = .0007), RAD51 (HR, 5.6; 95% CI, 1.7-18.3; P = .005), and PAR (HR, 2.2; 95% CI, 1.1-4.4; P = .026) was associated with worse OS. BRCA1, BRCA2, and PARP-1 expression was not associated with OS (P = .76, P = .38, and P = .09, respectively). A greater percentage of combined ERCC1 and RAD51 nuclear staining was strongly associated with worse OS (P = .005).

CONCLUSION

A high percentage of nuclear staining of ERCC1, RAD51, and PAR, assessed by immunohistochemistry, correlated with worse OS for patients with mUC treated with first-line platinum combination chemotherapy, supporting the evidence of the DNA repair pathways' role in the prognosis of mUC. We also report new evidence that RAD51 and PAR might play a role in the platinum response. Additional prospective studies are required to determine the prognostic or predictive nature of these biomarkers in mUC.

Evaluating a 4-marker signature of aggressive prostate cancer using time-dependent AUC

BACKGROUND

We previously identified a protein tumor signature of PTEN, SMAD4, SPP1, and CCND1 that, together with clinical features, was associated with lethal outcomes among prostate cancer patients. In the current study, we sought to validate the molecular model using time-dependent measures of AUC and predictive values for discriminating lethal from non-lethal prostate cancer.

METHODS

Using data from the initial study, we fit survival models for men with prostate cancer who were participants in the Physicians' Health Study (PHS; n = 276). Based on these models, we generated prognostic risk scores in an independent population, the Health Professionals Follow-up Study (HPFS; n = 347) to evaluate external validity. In each cohort, men were followed prospectively from cancer diagnosis through 2011 for development of distant metastasis or cancer mortality. We measured protein tumor expression of PTEN, SMAD4, SPP1, and CCND1 on tissue microarrays.

RESULTS

During a median of 11.9 and 14.3 years follow-up in the PHS and HPFS cohorts, 24 and 32 men (9%) developed lethal disease. When used as a prognostic factor in a new population, addition of the four markers to clinical variables did not improve discriminatory accuracy through 15 years of follow-up.

CONCLUSIONS

Although the four markers have been identified as key biological mediators in metastatic progression, they do not provide independent, long-term prognostic information beyond clinical factors when measured at diagnosis. This finding may underscore the broad heterogeneity in aggressive prostate tumors and highlight the challenges that may result from overfitting in discovery-based research.

Measuring PI3K Activation: Clinicopathologic, Immunohistochemical, and RNA Expression Analysis in Prostate Cancer

Assessing the extent of PI3K pathway activity in cancer is vital to predicting sensitivity to PI3K-targeting drugs, but the best biomarker of PI3K pathway activity in archival tumor specimens is unclear. Here, PI3K pathway activation was assessed, in clinical tissue from 1,021 men with prostate cancers, using multiple pathway nodes that include PTEN, phosphorylated AKT (pAKT), phosphorylated ribosomal protein S6 (pS6), and stathmin. Based on these markers, a 9-point score of PI3K activation was created using the combined intensity of the 4-markers and analyzed its association with proliferation (Ki67), apoptosis (TUNEL), and androgen receptor (AR) status, as well as pathologic features and cancer-specific outcomes. In addition, the PI3K activation score was compared with mRNA expression profiling data for a large subset of men. Interestingly, those tumors with higher PI3K activation scores also had higher Gleason grade (P = 0.006), increased AR (r = 0.37; P < 0.001) and Ki67 (r = 0.24; P < 0.001), and decreased TUNEL (r = -0.12; P = 0.003). Although the PI3K activation score was not associated with an increased risk of lethal outcome, a significant interaction between lethal outcome, Gleason and high PI3K score (P = 0.03) was observed. Finally, enrichment of PI3K-specific pathways was found in the mRNA expression patterns differentiating the low and high PI3K activation scores; thus, the 4-marker IHC score of PI3K pathway activity correlates with features of PI3K activation.

IMPLICATIONS

The relationship of this activation score to sensitivity to anti-PI3K agents remains to be tested but may provide more precision guidance when selecting patients for these therapies.

Comparing Platforms for Messenger RNA Expression Profiling of Archival Formalin-Fixed, Paraffin-Embedded Tissues

Archival formalin-fixed, paraffin-embedded (FFPE) tissue specimens represent a readily available but largely untapped resource for gene expression profiling-based biomarker discovery. Several technologies have been proposed to cope with the bias from RNA cross-linking and degradation associated with archival specimens to generate data comparable with RNA from fresh-frozen materials. Direct comparison studies of these RNA expression platforms remain rare. We compared two commercially available platforms for RNA expression profiling of archival FFPE specimens from clinical studies of prostate and ovarian cancer: the Affymetrix Human Gene 1.0ST Array following whole-transcriptome amplification using the NuGen WT-Ovation FFPE System V2, and the NanoString nCounter without amplification. For each assay, we profiled 7 prostate and 11 ovarian cancer specimens, with a block age of 4 to 21 years. Both platforms produced gene expression profiles with high sensitivity and reproducibility through technical repeats from FFPE materials. Sensitivity and reproducibility remained high across block age within each cohort. A strong concordance was shown for the transcript expression values for genes detected by both platforms. We showed the biological validity of specific gene signatures generated by both platforms for both cohorts. Our study supports the feasibility of gene expression profiling and large-scale signature validation on archival prostate and ovarian tumor specimens using commercial platforms. These approaches have the potential to aid precision medicine with biomarker discovery and validation.

DNA copy number analysis of metastatic urothelial carcinoma with comparison to primary tumors

Background

To date, there have been no reports characterizing the genome-wide somatic DNA chromosomal copy-number alteration landscape in metastatic urothelial carcinoma. We sought to characterize the DNA copy-number profile in a cohort of metastatic samples and compare them to a cohort of primary urothelial carcinoma samples in order to identify changes that are associated with progression from primary to metastatic disease.

Methods

Using molecular inversion probe array analysis we compared genome-wide chromosomal copy-number alterations between 30 metastatic and 29 primary UC samples. Whole transcriptome RNA-Seq analysis was also performed in primary and matched metastatic samples which was available for 9 patients.

Results

Based on a focused analysis of 32 genes in which alterations may be clinically actionable, there were significantly more amplifications/deletions in metastases (8.6% vs 4.5%, p < 0.001). In particular, there was a higher frequency of E2F3 amplification in metastases (30% vs 7%, p = 0.046). Paired primary and metastatic tissue was available for 11 patients and 3 of these had amplifications of potential clinical relevance in metastases that were not in the primary tumor including ERBB2, CDK4, CCND1, E2F3, and AKT1. The transcriptional activity of these amplifications was supported by RNA expression data.

Conclusions

The discordance in alterations between primary and metastatic tissue may be of clinical relevance in the era of genomically directed precision cancer medicine.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-015-1192-2) contains supplementary material, which is available to authorized users.

Untangling the tumor microenvironment:Illuminating the complex interactions and functions of immune cells

Certain antibody therapies have demonstrated the potential for directing a patient's own immune system against tumors. Further advances in this area will depend upon a detailed understanding of the tumor microenvironment and characterization of the location and status of immune cells and their interaction with tumor cells. This will require methods that provide phenotyping of immune and cancer cells combined with information about their spatial relationship in tumor regions. Additionally, a deeper understanding of the signaling cascades active in immune recognition of cancers is crucial. During this webinar, we will discuss the bringing together of multiplexed fluorescent immunohistochemistry, advanced microscopy techniques, and bioinformatics, and how these are now enabling new insights into cancer biology and immunology.

Multiplexed immunohistochemistry, imaging, and quantitation: a review, with an assessment of Tyramide signal amplification, multispectral imaging and multiplex analysis

Tissue sections offer the opportunity to understand a patient's condition, to make better prognostic evaluations and to select optimum treatments, as evidenced by the place pathology holds today in clinical practice. Yet, there is a wealth of information locked up in a tissue section that is only partially accessed, due mainly to the limitations of tools and methods. Often tissues are assessed primarily based on visual analysis of one or two proteins, or 2-3 DNA or RNA molecules. Even while analysis is still based on visual perception, image analysis is starting to address the variability of human perception. This is in contrast to measuring characteristics that are substantially out of reach of human perception, such as parameters revealed through co-expression, spatial relationships, heterogeneity, and low abundance molecules. What is not routinely accessed is the information revealed through simultaneous detection of multiple markers, the spatial relationships among cells and tissue in disease, and the heterogeneity now understood to be critical to developing effective therapeutic strategies. Our purpose here is to review and assess methods for multiplexed, quantitative, image analysis based approaches, using new multicolor immunohistochemistry methods, automated multispectral slide imaging, and advanced trainable pattern recognition software. A key aspect of our approach is presenting imagery in a workflow that engages the pathologist to utilize the strengths of human perception and judgment, while significantly expanding the range of metrics collectable from tissue sections and also provide a level of consistency and precision needed to support the complexities of personalized medicine.

Neoadjuvant dose-dense methotrexate, vinblastine, doxorubicin, and cisplatin with pegfilgrastim support in muscle-invasive urothelial cancer: pathologic, radiologic, and biomarker correlates

PURPOSE

In advanced urothelial cancer, treatment with dose-dense methotrexate, vinblastine, doxorubicin, and cisplatin (ddMVAC) results in a high response rate, less toxicity, and few dosing delays. We explored the efficacy and safety of neoadjuvant ddMVAC with pegfilgrastim support in muscle-invasive urothelial cancer (MIUC).

PATIENTS AND METHODS

Patients with cT2-cT4, N0-1, M0 MIUC were enrolled. Four cycles of ddMVAC were administered, followed by radical cystectomy. The primary end point was pathologic response (PaR) defined by pathologic downstaging to ≤ pT1N0M0. The study used Simon's optimal two-stage design to evaluate null and alternative hypotheses of PaR rate of 35% versus 55%. Secondary end points included toxicity, disease-free survival (DFS), radiologic response (RaR), and biomarker correlates, including ERCC1.

RESULTS

Between December 2008 and April 2012, 39 patients (cT2N0, 33%; cT3N0, 18%; cT4N0, 3%; cT2-4N1, 43%; unspecified, 3%) were enrolled. Median follow-up was 2 years. Overall, 49% (80% CI, 38 to 61) achieved PaR of ≤ pT1N0M0, and we concluded this regimen was effective. High-grade (grade ≥ 3) toxicities were observed in 10% of patients, with no neutropenic fevers or treatment-related death. One-year DFS was 89% versus 67% for patients who achieved PaR compared with those who did not (hazard ratio [HR], 2.6; 95% CI, 0.8 to 8.1; P = .08) and 86% versus 62% for patients who achieved RaR compared with those who did not (HR, 4.1; 95% CI, 1.3 to 12.5; P = .009). We found no association between serum tumor markers or ERCC1 expression with response or survival.

CONCLUSION

In patients with MIUC, neoadjuvant ddMVAC was well tolerated and resulted in significant pathologic and radiologic downstaging.

Androgen receptor CAG repeat polymorphism and risk of TMPRSS2:ERG-positive prostate cancer

BACKGROUND

The androgen receptor (AR) is an essential gene in prostate cancer pathogenesis and progression. Genetic variation in AR exists, including a polymorphic CAG repeat sequence that is inversely associated with transcriptional activity. Experimental data suggest that heightened AR activity facilitates formation of TMPRSS2:ERG, a gene fusion present in approximately 50% of tumors of patients with prostate cancer.

METHODS

We undertook a nested case-control study to investigate the hypothesis that shorter CAG repeat length would be associated with prostate cancer risk defined by TMPRSS2:ERG status. The study included 291 men with prostate cancer (147 ERG-positive) and 1,221 cancer-free controls. ORs and 95% confidence intervals (CI) were calculated using logistic regression.

RESULTS

Median CAG repeat length (interquartile range) among controls was 22 (20-24). Men with shorter CAG repeats had an increased risk of ERG-positive (OR, 1.07 per 1 repeat decrease; 95% CI, 1.00-1.14), but not ERG-negative prostate cancer (OR, 0.99 per 1 repeat decrease; 95% CI, 0.93-1.05).

CONCLUSIONS

These data suggest that shorter CAG repeats are specifically associated with development of TMPRSS2:ERG-positive prostate cancer.

IMPACT

Our results provide supportive evidence that androgen signaling underlies the development of prostate tumors that harbor TMPRSS2:ERG. Moreover, these results suggest that TMPRSS2:ERG may represent a unique molecular subtype of prostate cancer with an etiology distinct from TMPRSS2:ERG-negative disease.

FGFR3 expression in primary and metastatic urothelial carcinoma of the bladder

While fibroblast growth factor receptor 3 (FGFR3) is frequently mutated or overexpressed in nonmuscle-invasive urothelial carcinoma (UC), the prevalence of FGFR3 protein expression and mutation remains unknown in muscle-invasive disease. FGFR3 protein and mRNA expression, mutational status, and copy number variation were retrospectively analyzed in 231 patients with formalin-fixed paraffin-embedded primary UCs, 33 metastases, and 14 paired primary and metastatic tumors using the following methods: immunohistochemistry, NanoString nCounterTM, OncoMap or Affymetrix OncoScanTM array, and Gain and Loss of Analysis of DNA and Genomic Identification of Significant Targets in Cancer software. FGFR3 immunohistochemistry staining was present in 29% of primary UCs and 49% of metastases and did not impact overall survival (P = 0.89, primary tumors; P = 0.78, metastases). FGFR3 mutations were observed in 2% of primary tumors and 9% of metastases. Mutant tumors expressed higher levels of FGFR3 mRNA than wild-type tumors (P < 0.001). FGFR3 copy number gain and loss were rare events in primary and metastatic tumors (0.8% each; 3.0% and 12.3%, respectively). FGFR3 immunohistochemistry staining is present in one third of primary muscle-invasive UCs and half of metastases, while FGFR3 mutations and copy number changes are relatively uncommon.

Activating mTOR mutations in a patient with an extraordinary response on a phase I trial of everolimus and pazopanib

Understanding the genetic mechanisms of sensitivity to targeted anticancer therapies may improve patient selection, response to therapy, and rational treatment designs. One approach to increase this understanding involves detailed studies of exceptional responders: rare patients with unexpected exquisite sensitivity or durable responses to therapy. We identified an exceptional responder in a phase I study of pazopanib and everolimus in advanced solid tumors. Whole-exome sequencing of a patient with a 14-month complete response on this trial revealed two concurrent mutations in mTOR, the target of everolimus. In vitro experiments demonstrate that both mutations are activating, suggesting a biologic mechanism for exquisite sensitivity to everolimus in this patient. The use of precision (or "personalized") medicine approaches to screen patients with cancer for alterations in the mTOR pathway may help to identify subsets of patients who may benefit from targeted therapies directed against mTOR.

Integrative analysis of 1q23.3 copy-number gain in metastatic urothelial carcinoma

PURPOSE

Metastatic urothelial carcinoma of the bladder is associated with multiple somatic copy-number alterations (SCNAs). We evaluated SCNAs to identify predictors of poor survival in patients with metastatic urothelial carcinoma treated with platinum-based chemotherapy.

EXPERIMENTAL DESIGN

We obtained overall survival (OS) and array DNA copy-number data from patients with metastatic urothelial carcinoma in two cohorts. Associations between recurrent SCNAs and OS were determined by a Cox proportional hazard model adjusting for performance status and visceral disease. mRNA expression was evaluated for potential candidate genes by NanoString nCounter to identify transcripts from the region that are associated with copy-number gain. In addition, expression data from an independent cohort were used to identify candidate genes.

RESULTS

Multiple areas of recurrent significant gains and losses were identified. Gain of 1q23.3 was independently associated with a shortened OS in both cohorts [adjusted HR, 2.96; 95% confidence interval (CI), 1.35-6.48; P = 0.01 and adjusted HR, 5.03; 95% CI, 1.43-17.73; P < 0.001]. The F11R, PFDN2, PPOX, USP21, and DEDD genes, all located on 1q23.3, were closely associated with poor outcome.

CONCLUSIONS

1q23.3 copy-number gain displayed association with poor survival in two cohorts of metastatic urothelial carcinoma. The identification of the target of this copy-number gain is ongoing, and exploration of this finding in other disease states may be useful for the early identification of patients with poor-risk urothelial carcinoma. Prospective validation of the survival association is necessary to demonstrate clinical relevance.

Modification of the association between obesity and lethal prostate cancer by TMPRSS2:ERG

BACKGROUND

TMPRSS2:ERG is a hormonally regulated gene fusion present in about half of prostate tumors. We investigated whether obesity, which deregulates several hormonal pathways, interacts with TMPRSS2:ERG to impact prostate cancer outcomes.

METHODS

The study included 1243 participants in the prospective Physicians' Health Study and Health Professionals Follow-Up Study diagnosed with prostate cancer between 1982 and 2005. ERG overexpression (a TMPRSS2:ERG marker) was assessed by immunohistochemistry of tumor tissue from radical prostatectomy or transurethral resection of the prostate. Body mass index (BMI) and waist circumference, measured on average 1.3 years and 5.3 years before diagnosis, respectively, were available from questionnaires. Data on BMI at baseline was also available. We used Cox regression to calculate hazard ratios and 95% confidence intervals (CIs). All statistical tests were two-sided.

RESULTS

During a mean follow-up of 12.8 years, 119 men developed lethal disease (distant metastases or prostate cancer death). Among men with ERG-positive tumors, the multivariable hazard ratio for lethal prostate cancer was 1.48 (95% CI = 0.98 to 2.23) per 5-unit increase in BMI before diagnosis, 2.51 (95% CI = 1.26 to 4.99) per 8-inch increase in waist circumference before diagnosis, and 2.22 (95% CI = 1.35 to 3.63) per 5-unit increase in BMI at baseline. The corresponding hazard ratios among men with ERG-negative tumors were 1.10 (95% CI = 0.76 to1.59; P interaction = .24), 1.14 (95% CI = 0.62 to 2.10; P interaction = .09), and 0.78 (95% CI = 0.52 to 1.19; P interaction = .001).

CONCLUSIONS

These results suggest that obesity is linked with poorer prostate cancer prognosis primarily in men with tumors harboring the gene fusion TMPRSS2:ERG.

A co-clinical approach identifies mechanisms and potential therapies for androgen deprivation resistance in prostate cancer

Here we report an integrated analysis that leverages data from treatment of genetic mouse models of prostate cancer along with clinical data from patients to elucidate new mechanisms of castration resistance. We show that castration counteracts tumor progression in a Pten-loss driven mouse model of prostate cancer through the induction of apoptosis and proliferation block. Conversely, this response is bypassed upon deletion of either Trp53 or Lrf together with Pten, leading to the development of castration resistant prostate cancer (CRPC). Mechanistically, the integrated acquisition of data from mouse models and patients identifies the expression patterns of XAF1-XIAP/SRD5A1 as a predictive and actionable signature for CRPC. Importantly, we show that combined inhibition of XIAP, SRD5A1, and AR pathways overcomes castration resistance. Thus, our co-clinical approach facilitates stratification of patients and the development of tailored and innovative therapeutic treatments.

Phase II study of neoadjuvant dose-dense methotrexate, vinblastine, doxorubicin, and cisplatin (ddMVAC) chemotherapy in patients with muscle-invasive urothelial cancer (MI-UC): Pathologic and radiologic response, serum tumor markers, and DNA excision repair pathway biomarkers in relation to disease-free survival (DFS)

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Background: Neoadjuvant (NA) ddMVAC in patients (pts) with MI-UC is associated with significant pathologic response (PaR) and radiologic response (RaR). We examined the frequency of PaR and RaR as well as the level of serum and tissue biomarkers in correlation with DFS. Methods: Pts treated on phase II prospective study of NA ddMVAC (4 cycles) in MI-UC were evaluated for RaR (at least >50% decrease in the primary tumor and nodes after chemotherapy, with delayed enhancement of residual disease) and PaR (p<T1N0M0). Elevated serum tumor markers (CA125, C19-9 and ßHCG) at baseline and Day 1 of each cycle were documented. Expression level of baseline DNA ERCC1 protein in tumor biopsy tissues was determined by immunohistochemistry based on H-score <0.1 (negative) vs. >0.1 (positive). Fisher’s Exact test was used to evaluate association with response. Post-surgery DFS was estimated by the Kaplan-Meier method and compared between response and biomarker groups using the logrank test. Results: Of 39 pts (cT2:42%, cT3:42%, cT4:16%, and cN1:45%), 49% (90% CI 35-63) experienced PaR, and 62% (90% CI 47-75) achieved RaR after ddMVAC chemotherapy. Pts who achieved PaR experienced a DFS advantage, with 18-month DFS of 78% (95% CI 47-92) vs. 48% (95% CI 18-74) in those who did not (p=0.146). Those achieving RaR had a significantly longer DFS (p=0.006), with 18-month DFS of 87% (95% CI 57-97) vs. 29% (95% CI 5-60) in those who did not. Among 10 pts with any elevated serum tumor marker at baseline, only 2 pts showed normalization, both without a PaR. ERCC1(+) tumors were not associated with PaR, pT0 or RaR. DFS by ERCC1status was inconclusive due to limited sample size. 18-month DFS was 91% (95% CI 51-99) in ERCC1(+) tumors vs. 63% (95% CI 29-85) in ERCC1(-) tumors. Conclusions: ddMVAC achieves significant PaR and RaR in MI-UC pts that translates into a post-surgery DFS advantage. ERCC1(+) was not associated with response. More effective biomarkers of platinum response are needed to select pts most likely to benefit from NA therapy. Clinical trial information: NCT00808639.

Abstract LB-28: The IGF/insulin signaling axis TMPRSS2:ERG and prostate cancer survival

Background: One half of prostate cancers harbor the TMPRSS2:ERG fusion, a somatic event that may reflect a distinct disease molecular subtype. TMPRSS2 is androgen regulated and ERG is a transcription factor that is part of the ETS family. Based on experimental evidence, we hypothesized that TMPRSS2:ERG tumors would be more sensitive to the insulin like growth factor (IGF)/insulin signaling axis in prostate cancer survival.

Methods: We studied participants in the prospective Physicians' Health Study (PHS) and the Health Professionals Follow-Up Study (HPFS) diagnosed with prostate cancer from 1982 - 2005. TMPRSS2:ERG was assessed in tumor tissue microarrays by immunohistochemical evaluation of ERG expression (n=1,236). Pre-diagnostic plasma concentrations of IGF1 (n=307), IGFBP3 (n=307), c-peptide (n=293), and adiponectin (n=120), and tissue expression of the IGF1 receptor (IGF1R; n=713), insulin receptor (IR; n=682), and adionectin receptor (AdipoR2; n=840) were available among men with measured ERG expression. Men have been followed for biochemical recurrence and cancer mortality through 2012. We used Cox regression to estimate hazard ratios (HRs) and 95% confidence intervals (CI) of associations between circulating biomarkers, TMPRSS2:ERG and prostate cancer outcomes.

Results: Mean follow-up for lethal prostate cancer was 12.8 years and for recurrence 11.1 years. The number of lethal and recurrence events among men with measured blood markers were: IGF1/IGFBP3 25 and 61, c-peptide 20 and 56, and adiponectin 9 and 17, respectively. Among ERG negative tumors, comparing high vs. low concentrations, the multivariable HR for recurrence was 0.4 (95% CI 0.2-1.1) for IGF1, 1.1 (95% CI 0.5-2.8) for IGFBP3, 1.6 (95% CI 0.7-3.6) for c-peptide, and 1.4 (95% CI 0.3-5.6) for adiponectin. The corresponding HRs among ERG positive tumors were 1.8 (95% CI 0.8-4.0; p interaction 0.04) for IGF1, 0.8 (95% CI 0.4-1.8; p interaction 0.61) for IGFBP3, 0.6 (95% CI 0.3-1.3; p interaction 0.16) for c-peptide, and 0.8 (95% CI 0.2-3.6; p interaction 0.53) for adiponectin. Among ERG negative tumors, comparing high vs. low concentrations of the blood markers, the multivariable HR for lethal disease was 0.7 (95% CI 0.2-3.2) for IGF1, 1.4 (95% CI 0.3-5.9) for IGFBP3, 3.64 (95% CI 0.6-20.9) for c-peptide, and 1.1 (95% CI 0.2-7.8) for adiponectin. The corresponding HRs among ERG positive tumors were 2.3 (95% CI 0.5-11.1; p interaction 0.53) for IGF1, 0.6 (95% CI 0.1-2.3; p interaction 0.86) for IGFBP3, 0.7 (95% CI 0.2-2.9; p interaction 0.37) for c-peptide, and 0.4 (95% CI 0.03-5.4; p interaction 0.44) for adiponectin. The expression of IR, IGF1R, and AdipoR2 were significantly (all p-values &lt;0.01) higher in ERG positive vs. negative tumors.

Conclusions: Although the number of events were relatively small, our results support the hypothesis that TMPRSS2:ERG fusion may modify the association between the IGF/insulin signaling axis and prostate cancer prognosis.

Citation Format: Thomas U. Ahearn, Andreas Pettersson, Edward C. Stack, Jing Ma, Travis Gerke, Allison Meisner, Michael N. Pollak, Stephen Finn, Meir J. Stampfer, Massimo Loda, Edward L. Giovannucci, Lorelei A. Mucci. The IGF/insulin signaling axis TMPRSS2:ERG and prostate cancer survival. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr LB-28. doi:10.1158/1538-7445.AM2013-LB-28

Phase 2 study of dose-intense temozolomide in recurrent glioblastoma

BACKGROUND

Among patients with glioblastoma (GBM) who progress on standard temozolomide, the optimal therapy is unknown. Resistance to temozolomide is partially mediated by O(6)-methylguanine-DNA methyltransferase (MGMT). Because MGMT may be depleted by prolonged temozolomide administration, dose-intense schedules may overcome resistance.

METHODS

This was a multicenter, phase 2, single-arm study of temozolomide (75-100 mg/m(2)/day) for 21 days of each 28-day cycle. Patients had GBM in first recurrence after standard therapy. The primary end point was 6-month progression-free survival (PFS6).

RESULTS

Fifty-eight participants were accrued, 3 of whom were ineligible for analysis; one withdrew before response assessment. There were 33 men (61%), with a median age of 57 years (range, 25-79 years) and a median Karnofsky performance score of 90 (range, 60-100). Of 47 patients with MGMT methylation results, 36 (65%) had methylated tumors. There were 7 (13%) partial responses, and PFS6 was only 11%. Response and PFS did not depend on MGMT status; MSH2, MLH1, or ERCC1 expression; the number of prior temozolomide cycles; or the time off temozolomide. Treatment was well tolerated, with limited grade 3 neutropenia (n = 2) or thrombocytopenia (n = 2).

CONCLUSIONS

Dose-intense temozolomide on this schedule is safe in recurrent GBM. However, efficacy is marginal and predictive biomarkers are needed.

Relationship of ERCC1 genotype variant with mRNA expression and ERCC1 protein levels in advanced urothelial carcinoma (UC)

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Background: DNA repair factors may be predictive for response to chemotherapies that produce DNA damage. While low ERCC1 protein and mRNA levels have been reported as associated with improved outcomes in metastatic UC patients treated with platinum-based chemotherapy, the relationship between genotype, mRNA expression, and protein level is unknown. The ERCC1 germline 19007C>T single-nucleotide polymorphism (SNP) is functionally associated with reduced translation of ERCC1 mRNA. We investigated the relationship between ERCC1 germline SNP, ERCC1 tumor mRNA and protein expression, in a cohort of patients with advanced UC who received first-line, platinum-based chemotherapy. Methods: A cohort of clinically annotated, uniformly-treated advanced UC patients with FFPE primary tumor tissue available was identified through the Hellenic cooperative Oncology Group (HECOG) (N=93). Genomic DNA extraction, nested PCR, and restriction fragment length polymorphism techniques for the 19007C>T SNP were performed to identify C/C, C/T and T/T genotypes. ERCC1 mRNA expression was interrogated using Nanostring nCounter profiling. IHC analysis was performed on tissue arrays using an ERCC1 antibody. Percent of positive nuclear staining was categorized as quartiles using previously identified cut-points. Results: ERCC1 C/T genotype was identified in 30/61 samples (49%) and T/T in 14/61 samples (23%). In 54 patients with both SNP and mRNA data available, T/T genotype was associated with the highest level of mRNA expression, followed by the C/T genotype (p=0.04). Neither ERCC1 genotype (N=44) nor ERCC1 mRNA expression (N=54) was associated with ERCC1 protein expression as measured by IHC (p=0.52 and p=0.13, respectively). Conclusions: ERCC1 19007C>T is associated with increased ERCC1 mRNA expression. However, neither genotype nor mRNA are surrogates for ERCC1 protein detected by IHC in advanced UC tumors. This suggests that while genotype influences mRNA expression of ERCC1, the use of the nucleotide excision repair pathway as a predictive biomarker of platinum-sensitivity may be more complex than previously appreciated and require the integrative use of proteomics, genomics and epigenomics.

Peroxisome proliferator-activated receptor gamma (PPARG) gene amplifications in urothelial carcinoma (UC)

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Background: PPARy is a steroid hormone receptor encoded by the PPARG gene (Chr 3p25). Data are conflicting regarding its role in UC. Some studies suggest activation has antiproliferative effects, and preclinical data indicate a potential role for PPARy agonists in cancer treatment. However, recent findings show that use of the PPARy agonist thiazolidinones (TZD) in type 2 diabetes is associated with increased risk of developing UC. To define the spectrum of PPARy aberrations in UC, DNA was evaluated to detect copy number gains/losses (CNG/CNL) of PPARG in three clinically annotated UC cohorts. Methods: Cohort A contained 97 patients with high-grade UC. Cohort B contained 94 patients with primary bladder tumors who developed metastatic UC. Cohort C had 33 patients with metastatic UC, including both primary and paired metastatic tissue for 14 patients. DNA from all tumors was subjected to copy number analysis (array comparative genomic hybridization for cohorts A and B and molecular inversion probe array for cohort C) to identify focal areas of CNG/CNL. Statistical analysis using RAE (cohort A) or GISTIC 2.0 (with CNG defined as log2 copy number ratio >0.8) in cohorts B/C was used to identify significant alterations. Results: The region containing PPARG showed CNG in 7%, 10%, and 15% of cohorts A, B and C, respectively. In cohort A, RAE p value was 5.36E-05 at the amplicon containing PPARG. In cohorts B and C GISTIC 2.0 q values were 9.75E-12 and 6.04E-10. PPARG CNG had no impact on survival in the cohorts with available survival data (A and B). Paired biopsies from primary and metastatic sites showed discordance in PPARG CNG in 2 cases. In 1 case CNG was present in the metastasis but not in the primary and in 1 case the opposite occurred. Conclusions: PPARG shows significant CNGs in 7-15% of UC. Notably the RAF1 locus (a known oncogene) lies close to PPARG and could also represent the driver alteration within this amplicon. Investigation of the functional relevance of these CNGs is clearly warranted as it may be a driver of bladder cancer growth and progression. Determination of PPARG CNG status in UCs in a TZD treated population may provide mechanistic insights into the increased incidence of UC in patients treated with these agents.

A phase II multicenter study of neoadjuvant dose-dense methotrexate, vinblastine, doxorubicin, and cisplatin (ddMVAC) chemotherapy with pegfilgrastim support in patients (pts) muscle-invasive urothelial cancer (MIUC): Safety, pathologic, radiologic, and molecular correlates

278

Background: ddMVAC is associated with high responses rate (RR) in advanced urothelial cancer (UC). We embarked on a study in MIUC to determine pathologic RR and its correlation with clinical and radiological outcomes as well as DNA excision repair pathway biomarkers (ERCC1, PAR, BRCA1, and BRCA2). Methods: Patients with cT2-T4, N0-1, M0 UC, and adequate kidney and marrow function were enrolled on a prospective multicenter phase II trial. Four cycles of ddMVAC were given followed by radical cystectomy (RC). The primary endpoint was pathologic downstaging to <pT1N0M0. The treatment would be considered effective if 17 of 37 eligible patients (46%) met the primary endpoint (85% power, 1-sided type I error 0.1). Secondary endpoints included safety, imaging response (by contrast-enhanced imaging, largely MRI), and biomarker correlates. Results: Between 12/08 and 4/12, 39 pts (cT2:42%; cT3:42%, cT4:16%, N1:45%) were enrolled. 91% had bladder primary, and 95% received 4 cycles of ddMVAC. Median follow up was 18 months. One patient developed distant metastases before RC. Of 39 eligible pts, 49% (90% CI 35-63) downstaged to <pT1N0M0 (pT0N0=26%), and the primary endpoint was met. 14/17 (82%) of pts with cN1 disease had pN0 at surgery; no pts with cN0 was found to have pN(+). Toxicities >Grade 3 related to chemotherapy were observed in 10% of pts and included mucositis, hand-foot skin reaction, hypokalemia and neutropenia. No neutropenic fevers were seen. Median and 18-month disease-free survival (DFS) is provided in Table. Tissue biomarker analyses will be presented. Conclusions: ddMVAC regimen is well tolerated and results in significant pathologic and radiologic downstaging in pts with MIUC. Clinical trial information: NCT00808639. [Table: see text]

Genomic characterization of metastatic urothelial carcinoma

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Background: The genetic profile of primary urothelial carcinoma (UC) has been well documented but no reports analyze specific chromosomal alterations in metastatic disease. We performed molecular inversion probe array (MIP) analysis to compare chromosomal gains or losses in metastatic and primary UC samples. Methods: 33 samples of metastatic UC and 30 primary samples were analyzed from 48 patients (pts), of which paired primary and metastatic tissue was available for 14 pts. DNA from all samples was subjected to molecular inversion probe array analysis to identify focal areas of copy number gain (CNG) or loss (CNL). We focused this analysis on 21 genes from signaling pathways known to be of interest in UC (Table). CNG or CNL was defined as a log2 copy number ratio ≥ 0.8 or ≤ -0.8. GISTIC 2.0 was used to identify significantly altered regions. Results: In the loci analyzed, there were significantly more alterations in metastases than primary samples (8.4% vs 4.3% p=0.002). In particular, there was a significantly higher frequency of E2F3CNG in metastases (27% vs 7% p=0.046). There was frequent discordance in alterations when comparing primary and metastatic tissue from the same patients: 7 of 14 pts harbored potentially oncogenic CNG/CNL in their metastases that were not present in the primary. Conclusions: More alterations in UC-relevant genes were identified in metastases compared with primary tumors, in keeping with the multistep model of cumulative genetic change in cancer progression. More frequent CNG of the E2F3 gene was noted and may represent a mechanism of UC progression. Frequent discordance in alterations between primaries and metastases may be of significant clinical relevance in the future when selecting patients for appropriate molecularly targeted therapy. [Table: see text]

Opposing effects of androgen deprivation and targeted therapy on prostate cancer prevention

Prostate cancer is an ideal target for chemoprevention. To date, chemoprevention clinical trials with 5α-reductase inhibitors have yielded encouraging yet ultimately confounding results. Using a preclinical mouse model of high-grade prostatic intraepithelial neoplasia (HG-PIN) induced by PTEN loss, we observed unprecedented deteriorating effects of androgen deprivation, in which surgical castration or MDV3100 treatment accelerated disease progression of the otherwise stable HG-PIN to invasive castration-resistant prostate cancer (CRPC). As an alternative, targeting the phosphoinositide 3-kinase (PI3K) signaling pathway via either genetic ablation of genes encoding PI3K components or pharmacologic inhibition of the PI3K pathway reversed the PTEN loss-induced HG-PIN phenotype. Finally, concurrent inhibition of the PI3K and mitogen-activated protein kinase (MAPK) pathways was effective in blocking the growth of PTEN-null CRPC. Together, these data have revealed the potential adverse effects of antiandrogen chemoprevention in certain genetic contexts (such as PTEN loss) while showing the promise of targeted therapy in the clinical management of this complex and prevalent disease.

SIGNIFICANCE

Chemoprevention with antiandrogen therapies is attractive for prostate cancer, given its prevalence and established hormonally mediated pathogenesis. However, because PTEN loss has been found in 9% to 45% of HG-PIN in the clinic, the current findings suggest that patients with PTEN-deficient prostate tumors might be better treated with PI3K-targeted therapies.

EZH2 oncogenic activity in castration-resistant prostate cancer cells is Polycomb-independent

Epigenetic regulators represent a promising new class of therapeutic targets for cancer. Enhancer of zeste homolog 2 (EZH2), a subunit of Polycomb repressive complex 2 (PRC2), silences gene expression via its histone methyltransferase activity. We found that the oncogenic function of EZH2 in cells of castration-resistant prostate cancer is independent of its role as a transcriptional repressor. Instead, it involves the ability of EZH2 to act as a coactivator for critical transcription factors including the androgen receptor. This functional switch is dependent on phosphorylation of EZH2 and requires an intact methyltransferase domain. Hence, targeting the non-PRC2 function of EZH2 may have therapeutic efficacy for treating metastatic, hormone-refractory prostate cancer.

The TMPRSS2:ERG rearrangement, ERG expression, and prostate cancer outcomes: a cohort study and meta-analysis

BACKGROUND

Whether the genomic rearrangement transmembrane protease, serine 2 (TMPRSS2):v-ets erythroblastosis virus E26 oncogene homolog (ERG) has prognostic value in prostate cancer is unclear.

METHODS

Among men with prostate cancer in the prospective Physicians' Health and Health Professionals Follow-Up Studies, we identified rearrangement status by immunohistochemical assessment of ERG protein expression. We used Cox models to examine associations of ERG overexpression with biochemical recurrence and lethal disease (distant metastases or cancer-specific mortality). In a meta-analysis including 47 additional studies, we used random-effects models to estimate associations between rearrangement status and outcomes.

RESULTS

The cohort consisted of 1,180 men treated with radical prostatectomy between 1983 and 2005. During a median follow-up of 12.6 years, 266 men experienced recurrence and 85 men developed lethal disease. We found no significant association between ERG overexpression and biochemical recurrence [hazard ratio (HR), 0.99; 95% confidence interval (CI), 0.78-1.26] or lethal disease (HR, 0.93; 95% CI, 0.61-1.43). The meta-analysis of prostatectomy series included 5,074 men followed for biochemical recurrence (1,623 events), and 2,049 men followed for lethal disease (131 events). TMPRSS2:ERG was associated with stage at diagnosis [risk ratio (RR)(≥T3 vs. T2), 1.23; 95% CI, 1.16-1.30) but not with biochemical recurrence (RR, 1.00; 95% CI, 0.86-1.17) or lethal disease (RR, 0.99; 95% CI, 0.47-2.09).

CONCLUSIONS

These results suggest that TMPRSS2:ERG, or ERG overexpression, is associated with tumor stage but does not strongly predict recurrence or mortality among men treated with radical prostatectomy.

IMPACT

This is the largest prospective cohort study to examine associations of ERG overexpression and lethal prostate cancer among men treated with radical prostatectomy.

External validation of somatic copy number alteration (SCNA) at chromosome 1q23.3 in advanced urothelial carcinoma (UC)

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Background: Advanced UC is associated with multiple SNCAs. To identify SCNA predictors of poor survival in advanced UC, we evaluated SCNAs in two cohorts of high-risk urothelial carcinoma of the bladder. Methods: We obtained DNA copy number data from bladder cancer patients in two independent cohorts [Spanish cohort (n= 93, Agilent aCGH 180k array) and Brigham and Women’s/Dana-Farber (BW/DF) cohort (n = 48, Affymetrix OncoScan FFPE Express 2.0)]. For the BW/DF cohort, we acquired copy number information from 30 primary tumors and 33 metastases. For 12 patients, both primary and matched metastases were available. The GISTIC method was used on GLAD segmented data to identify driver copy number lesions, and the NBC algorithm to identify recurrent breakpoints. Cox proportional hazards models were used to estimate the effect of the identified SCNAs on overall survival, defined as time from start of chemotherapy for metastatic disease (Spanish) or from metastatic recurrence (BW/DF). Copy numbers were incorporated in the Cox models as continuous measures. Statistical significance of optimal cutpoints was estimated with permutation tests. Copy number profiles of primary tumors and metastases were compared with hierarchical clustering. Results: Amplification of 1q23.3 was independently associated with overall survival in both cohorts (Spanish cohort: HR 3.98; 95% 1.64-9.67; p < 0.03; C-statistic 0.54, 95% 0.45-0.65. BW/DF cohort: HR 6.28; 95% 1.84-21.4; p < 0.042; C-statistic 0.62, 95% 0.48-0.76). Amplifications at 22q12.2 were enriched in patients who developed metastasis (p < 0.05). A breakpoint analysis identified possible truncations of ITPR1 (Spanish: 15%; BW/DF: 25%) and PRIM2 (Spanish: 31% BW/DF: 12.5%) in large numbers of samples. For primary tumors with matched metastases, we observed that metastases clustered together with their primary tumors. Conclusions: External validation of the 1q23.3 amplification demonstrates the association of this SCNA with poor outcomes in advanced UC; the identification of the target of this copy number gain is ongoing. Gene truncations and their biological significance require further experimental investigation.

Multidimensional investigation of HER2 in advanced urothelial carcinoma (UC)

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Background: Incidence of Her2 positivity and association with overall survival (OS) are controversial in advanced UC. Activating Her2 mutations have been identified in other cancers, but they have not been previously reported in UC. We determined Her2 status by immunohistochemistry (IHC), fluorescence in situ hybridization (FISH), and copy number gain (CNG) via array CGH of primary UC tumors from patients (pts) with metastatic disease. Targeted Her2 sequencing was performed at known mutation hotspots, and mutation effect was investigated in vitro. Methods: Tissue microarrays of formalin fixed paraffin-embedded tumor from 98 UC pts treated with platinum-based combination chemotherapy for metastatic disease were evaluated for Her2 protein and for Her2 gene amplification by using standard clinical protocols. Positive staining was defined as an IHC score of 3+ or a FISH ratio of ≥2 using scoring criteria established for evaluation of breast cancer. Her2 CNG was evaluated by aCGH with cutoff log base 2 ratio > 0.9. Mutation status was validated by hME sequencing. OS was measured from start of treatment for metastatic disease. Association of OS and Her2 status was assessed by a Cox regression model. NIH-3T3 cells with Her2 V777L were assessed for growth, invasion, and Her2 kinase activation. Results: 22% of pts had 3+ Her2 staining by IHC. 21% of pts had FISH amplification. These were concordant in 78% of pts. CNG was identified in 16% and was concordant with FISH and IHC 85% and 88% of the time, respectively. Her2 status by any modality showed no significant association with OS in either univariate [HR=0.94, 95% CI: (0.52, 1.70), p=0.83] or multivariate [HR=1.12, 95% CI: (0.61, 2.06), p=0.72] analysis. Her2 mutations (V777L and L755S) were identified in 2 pts (2%). In vitro analysis of V777L results in transformation of NIH-3T3 cells, leading to increased growth, invasion on soft agar, and Her2 kinase constitutive activation. Conclusions: Her2 overexpression or amplification in the primary tumor does not predict OS in pts with metastatic UC. Other research has suggested that V777L sensitizes cells to lapatinib, while L755S leads to lapatinib resistance. These rare oncogenic Her2 mutations occur and may be therapeutic targets in selected pts.

PI3KCA mutations in advanced urothelial carcinoma: A potential therapeutic target?

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Background: PI3KCA is frequently mutated in human cancer; however, information is scarce regarding its relevance in urothelial carcinoma (UC). We determined the prevalence of mutation and impact on clinical outcome of PI3KCA uniformly-treated patients with metastatic UC. Impact of PI3K and dual PI3K/mTOR inhibition was tested in vitro in UC cell lines with either H1047R or E545K mutation. Methods: 141 samples from invasive UC were scanned for mutations. Of those, complete clinical data was available from 85 cases treated with platinum-based combination chemotherapy for advanced or metastatic disease. DNA was extracted from FFPE material. Mutation status was determined by iPLEX sequencing and confirmed with hME sequencing. Overall survival (OS) was measured from beginning of treatment for metastatic disease to time of death or censored on the last known alive date. Cox proportional hazard model was used to assess the associations of PI3K mutational status and OS. Growth inhibitory effects of a specific PI3K inhibitor and a dual PI3K/mTOR inhibitor (both from Selleck) on UC cell lines with or without mutations were tested using MTT assays. Results: Mutations in the PI3KCA gene were observed in 14 (10%; 95% CI 6-16%) specimens. E545K was detected in all 14 specimens, though one specimen contained mutation at both E545K and H1047R. Among patients with clinical data, there was no statistically significant association between PI3KCA mutational status and OS (HR for having PI3KCA=0.49, 95% CI [0.15, 1.57], p-value 0.22). Preliminary in vitro experiments showed that cell growth was more potently inhibited with dual PI3K/mTOR inhibitors than with PI3K inhibitors. Conclusions: Mutations in the PI3KCA gene were detected in 10% of invasive UC and did not correlate with OS in patients with metastatic UC treated with platinum-based chemotherapy. PI3K inhibition in vitro impacts UC cell growth, though dual PI3K/mTOR inhibitors may have more significant effects than PI3K inhibition alone.

FGFR3 protein expression and gene mutation in primary and metastatic urothelial carcinoma (UC) tumors

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Background: FGFR3 protein expression may represent a valid therapeutic target in metastatic UC. The prevalence of both mutation and overexpression is unknown in metastatic UC. Methods: Tissue microarrays of formalin fixed paraffin-embedded urothelial carcinomas (UC) were stained for FGFR3 by immunohistochemistry (IHC) [primary (n=250); metastatic (n=31); of which (n=14) were paired]. FGFR3 immunostaining was scored as negative or positive based on previously reported scoring systems. FGFR3 mutation in primary tumors was assessed by iPlex and confirmed by hME sequencing (n=141) or Affymetrix OncoScan FFPE Express 2.0 (primary: n=17; metastases n=31). Results: FGFR3 IHC positivity was present in 48% of metastases (95% CI=32-65%) and 26% of primary tumors, (95%=CI 21-32%), though strong staining was rare (<1%). Paired primary and metastatic tumors were both negative in 50% of cases, with 14% positive only in the metastasis, 14% positive only in the primary tumor, and 21% positive in both. If the primary tumor showed staining, 71% of the metastases showed staining. FGFR3 IHC staining did not impact overall survival (p=0.8). FGFR3 mutations were observed in 9.6% of metastatic tumors (95% CI=3.3-25%), compared to 3.5% of primary tumors (95% CI=1.5%-8%). Co-occurrence of mutation and FGFR3 DNA copy number gain was observed in one specimen. Conclusions: FGFR3 IHC staining is present 26 % of primary tumors of patients who go on to develop metastatic disease, and nearly half of metastatic tumor sites. FGFR3 mutation frequency in primary and metastatic tumor specimens is low. Further investigation of the frequency of FGFR3 protein expression in metastases is needed. The presence of FGFR3 protein by IHC staining in primary and metastatic specimens suggests that FGFR3 may represent a therapeutic target even in the absence of mutation. Further functional studies are needed.

A novel role for calcium/calmodulin kinase II within the brainstem pedunculopontine tegmentum for the regulation of wakefulness and rapid eye movement sleep

Considerable evidence suggests that the brainstem pedunculopontine tegmentum (PPT) neurons are critically involved in the regulation of rapid eye movement (REM) sleep and wakefulness (W); however, the molecular mechanisms operating within the PPT to regulate these two behavioral states remain relatively unknown. Here we demonstrate that the levels of calcium/calmodulin kinase II (CaMKII) and phosphorylated CaMKII expression in the PPT decreased and increased with 'low W with high REM sleep' and 'high W/low REM sleep' periods, respectively. These state-specific expression changes were not observed in the cortex, or in the immediately adjacent medial pontine reticular formation. Next, we demonstrate that CaMKII activity in the PPT is negatively and positively correlated with the 'low W with high REM sleep' and 'high W/low REM sleep' periods, respectively. These differences in correlations were not seen in the medial pontine reticular formation CaMKII activity. Finally, we demonstrate that with increased PPT CaMKII activity observed during high W/low REM sleep, there were marked shifts in the expression of genes that are involved in components of various signal transduction pathways. Collectively, these results for the first time suggest that the increased CaMKII activity within PPT neurons is associated with increased W at the expense of REM sleep, and this process is accomplished through the activation of a specific gene expression profile.

Identification of cholinergic and non-cholinergic neurons in the pons expressing phosphorylated cyclic adenosine monophosphate response element-binding protein as a function of rapid eye movement sleep

Recent studies have shown that in the pedunculopontine tegmental nucleus (PPT), increased neuronal activity and kainate receptor-mediated activation of intracellular protein kinase A (PKA) are important physiological and molecular steps for the generation of rapid eye movement (REM) sleep. In the present study performed on rats, phosphorylated cyclic AMP response element-binding protein (pCREB) immunostaining was used as a marker for increased intracellular PKA activation and as a reflection of increased neuronal activity. To identify whether activated cells were either cholinergic or noncholinergic, the PPT and laterodorsal tegmental nucleus (LDT) cells were immunostained for choline acetyltransferase (ChAT) in combination with pCREB or c-Fos. The results demonstrated that during high rapid eye movement sleep (HR, approximately 27%), significantly higher numbers of cells expressed pCREB and c-Fos in the PPT, of which 95% of pCREB-expressing cells were ChAT-positive. With HR, the numbers of pCREB-positive cells were also significantly higher in the medial pontine reticular formation (mPRF), pontine reticular nucleus oral (PnO), and dorsal subcoeruleus nucleus (SubCD) but very few in the locus coeruleus (LC) and dorsal raphe nucleus (DRN). Conversely, with low rapid eye movement sleep (LR, approximately 2%), the numbers of pCREB expressing cells were very few in the PPT, mPRF, PnO, and SubCD but significantly higher in the LC and DRN. The results of regression analyses revealed significant positive relationships between the total percentages of REM sleep and numbers of ChAT+/pCREB+ (Rsqr=0.98) cells in the PPT and pCREB+ cells in the mPRF (Rsqr=0.88), PnO (Rsqr=0.87), and SubCD (Rsqr=0.84); whereas significantly negative relationships were associated with the pCREB+ cells in the LC (Rsqr=0.70) and DRN (Rsqr=0.60). These results provide evidence supporting the hypothesis that during REM sleep, the PPT cholinergic neurons are active, whereas the LC and DRN neurons are inactive. More importantly, the regression analysis indicated that pCREB activation in approximately 98% of PPT cholinergic neurons, was caused by REM sleep. Moreover the results indicate that during REM sleep, PPT intracellular PKA activation and a transcriptional cascade involving pCREB occur exclusively in the cholinergic neurons.

Combined riluzole and sodium phenylbutyrate therapy in transgenic amyotrophic lateral sclerosis mice

Recent evidence suggests that transcriptional dysregulation may play a role in the pathogenesis of amyotrophic lateral sclerosis (ALS). The histone deacetylase inhibitor, sodium phenylbutyrate (NaPB), is neuroprotective and corrects aberrant gene transcription in ALS mice and has recently been shown to be safe and tolerable in ALS patients while improving hypoacetylation. Since many patients are already on riluzole, it is important to ensure that any proposed therapy does not result in negative synergy with riluzole. The combined treatment of riluzole and NaPB significantly extended survival and improved both the clinical and neuropathological phenotypes in G93A transgenic ALS mice beyond either agent alone. Combination therapy increased survival by 21.5%, compared to the separate administration of riluzole (7.5%) and NaPB (12.8%), while improving both body weight loss and grip strength. The data show that the combined treatment was synergistic. In addition, riluzole/NaPB treatment ameliorated gross lumbar and ventral horn atrophy, attenuated lumbar ventral horn neuronal cell death, and decreased reactive astrogliosis. Riluzole/NaPB administration increased acetylation at H4 and increased NF-kappaB p50 translocation to the nucleus in G93A mice, consistent with a therapeutic effect. These data suggest that NaPB may not interfere with the pharmacologic action of riluzole in ALS patients.

Modulation of nucleosome dynamics in Huntington's disease

Transcriptional dysregulation and aberrant chromatin remodeling are central features in the pathology of Huntington's disease (HD). In order to more fully characterize these pathogenic events, an assessment of histone profiles and associated gene changes were performed in transgenic N171-82Q (82Q) and R6/2 HD mice. Analyses revealed significant chromatin modification, resulting in reduced histone acetylation with concomitant increased histone methylation, consistent with findings observed in HD patients. While there are no known interventions that ameliorate or arrest HD progression, DNA/RNA-binding anthracyclines may provide significant therapeutic potential by correcting pathological nucleosome changes and realigning transcription. Two such anthracyclines, chromomycin and mithramycin, improved altered nucleosome homeostasis in HD mice, normalizing the chromatin pattern. There was a significant shift in the balance between methylation and acetylation in treated HD mice to that found in wild-type mice, resulting in greater acetylation of histone H3 at lysine 9 and promoting gene transcription. Gene expression profiling in anthracycline-treated HD mice showed molecular changes that correlate with disease correction, such that a subset of downregulated genes were upregulated with anthracycline treatment. Improved nucleosomal dynamics were concurrent with a significant improvement in the behavioral and neuropathological phenotype observed in HD mice. These data show the ability of anthracycline compounds to rebalance epigenetic histone modification and, as such, may provide the rationale for the design of human clinical trials in HD patients.

Dose ranging and efficacy study of high-dose coenzyme Q10 formulations in Huntington's disease mice

There is substantial evidence that a bioenergetic defect may play a role in the pathogenesis of Huntington's Disease (HD). A potential therapy for remediating defective energy metabolism is the mitochondrial cofactor, coenzyme Q10 (CoQ10). We have reported that CoQ10 is neuroprotective in the R6/2 transgenic mouse model of HD. Based upon the encouraging results of the CARE-HD trial and recent evidence that high-dose CoQ10 slows the progressive functional decline in Parkinson's disease, we performed a dose ranging study administering high levels of CoQ10 from two commercial sources in R6/2 mice to determine enhanced efficacy. High dose CoQ10 significantly extended survival in R6/2 mice, the degree of which was dose- and source-dependent. CoQ10 resulted in a marked improvement in motor performance and grip strength, with a reduction in weight loss, brain atrophy, and huntingtin inclusions in treated R6/2 mice. Brain levels of CoQ10 and CoQ9 were significantly lower in R6/2 mice, in comparison to wild type littermate control mice. Oral administration of CoQ10 elevated CoQ10 plasma levels and significantly increased brain levels of CoQ9, CoQ10, and ATP in R6/2 mice, while reducing 8-hydroxy-2-deoxyguanosine concentrations, a marker of oxidative damage. We demonstrate that high-dose administration of CoQ10 exerts a greater therapeutic benefit in a dose dependent manner in R6/2 mice than previously reported and suggest that clinical trials using high dose CoQ10 in HD patients are warranted.

Combination therapy using minocycline and coenzyme Q10 in R6/2 transgenic Huntington's disease mice

Huntington's disease (HD) is a fatal neurodegenerative disorder of genetic origin with no known therapeutic intervention that can slow or halt disease progression. Transgenic murine models of HD have significantly improved the ability to assess potential therapeutic strategies. The R6/2 murine model of HD, which recapitulates many aspects of human HD, has been used extensively in pre-clinical HD therapeutic treatment trials. Of several potential therapeutic candidates, both minocycline and coenzyme Q10 (CoQ10) have been demonstrated to provide significant improvement in the R6/2 mouse. Given the specific cellular targets of each compound, and the broad array of abnormalities thought to underlie HD, we sought to assess the effects of combined minocycline and CoQ10 treatment in the R6/2 mouse. Combined minocycline and CoQ10 therapy provided an enhanced beneficial effect, ameliorating behavioral and neuropathological alterations in the R6/2 mouse. Minocycline and CoQ10 treatment significantly extended survival and improved rotarod performance to a greater degree than either minocycline or CoQ10 alone. In addition, combined minocycline and CoQ10 treatment attenuated gross brain atrophy, striatal neuron atrophy, and huntingtin aggregation in the R6/2 mice relative to individual treatment. These data suggest that combined minocycline and CoQ10 treatment may offer therapeutic benefit to patients suffering from HD.

Chronology of behavioral symptoms and neuropathological sequela in R6/2 Huntington's disease transgenic mice

Genetic murine models play an important role in the study of human neurological disorders by providing accurate and experimentally accessible systems to study pathogenesis and to test potential therapeutic treatments. One of the most widely employed models of Huntington's disease (HD) is the R6/2 transgenic mouse. To characterize this model further, we have performed behavioral and neuropathological analyses that provide a foundation for the use of R6/2 mice in preclinical therapeutic trials. Behavioral analyses of the R6/2 mouse reveal age-related impairments in dystonic movements, motor performance, grip strength, and body weight that progressively worsen until death. Significant neuropathological sequela, identified as increasing marked reductions in brain weight, are present from 30 days, whereas decreased brain volume is present from 60 days and decreased neostriatal volume and striatal neuron area, with a concomitant reduction in striatal neuron number, are present at 90 days of age. Huntingtin-positive aggregates are present at postnatal day 1 and increase in number and size with age. Our findings suggest that the R6/2 HD model exhibits a progressive HD-like behavioral and neuropathological phenotype that more closely corresponds to human HD than previously believed, providing further assurance that the R6/2 mouse is an appropriate model for testing potential therapies for HD.

Genetic and pharmacological inactivation of the adenosine A2A receptor attenuates 3-nitropropionic acid-induced striatal damage

Adenosine A2A receptor (A2AR) antagonism attenuates 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced dopaminergic neurodegeneration and quinolinic acid-induced excitotoxicity in the neostriatum. As A2ARs are enriched in striatum, we investigated the effect of genetic and pharmacological A2A inactivation on striatal damage produced by the mitochondrial complex II inhibitor 3-nitropriopionic acid (3-NP). 3-NP was administered to A2AR knockout (KO) and wild-type (WT) littermate mice over 5 days. Bilateral striatal lesions were analyzed from serial brain tissue sections. Whereas all of the 3-NP-treated WT mice (C57BL/6 genetic background) had bilateral striatal lesions, only one of eight of the 3-NP-treated A2AR KO mice had detectable striatal lesions. Similar attenuation of 3-NP-induced striatal damage was observed in A2AR KO mice in a 129-Steel background. In addition, the effect of pharmacological antagonism on 3-NP-induced striatal neurotoxicity was tested by pre-treatment of C57Bl/6 mice with the A2AR antagonist 8-(3-chlorostyryl) caffeine (CSC). Although bilateral striatal lesions were observed in all mice treated either with 3-NP alone or 3-NP plus vehicle, there were no demonstrable striatal lesions in mice treated with CSC (5 mg/kg) plus 3-NP and in five of six mice treated with CSC (20 mg/kg) plus 3-NP. We conclude that both genetic and pharmacological inactivation of the A2AR attenuates striatal neurotoxicity produced by 3-NP. Since the clinical and neuropathological features of 3-NP-induced striatal damage resemble those observed in Huntington's disease, the results suggest that A2AR antagonism may be a potential therapeutic strategy in Huntington's disease patients.