Tara Spivey

An immunologic portrait of cancer

The advent of high-throughput technology challenges the traditional histopathological classification of cancer, and proposes new taxonomies derived from global transcriptional patterns. Although most of these molecular re-classifications did not endure the test of time, they provided bulk of new information that can reframe our understanding of human cancer biology. Here, we focus on an immunologic interpretation of cancer that segregates oncogenic processes independent from their tissue derivation into at least two categories of which one bears the footprints of immune activation. Several observations describe a cancer phenotype where the expression of interferon stimulated genes and immune effector mechanisms reflect patterns commonly observed during the inflammatory response against pathogens, which leads to elimination of infected cells. As these signatures are observed in growing cancers, they are not sufficient to entirely clear the organism of neoplastic cells but they sustain, as in chronic infections, a self-perpetuating inflammatory process. Yet, several studies determined an association between this inflammatory status and a favorable natural history of the disease or a better responsiveness to cancer immune therapy. Moreover, these signatures overlap with those observed during immune-mediated cancer rejection and, more broadly, immune-mediated tissue-specific destruction in other immune pathologies. Thus, a discussion concerning this cancer phenotype is warranted as it remains unknown why it occurs in immune competent hosts. It also remains uncertain whether a genetically determined response of the host to its own cancer, the genetic makeup of the neoplastic process or a combination of both drives the inflammatory process. Here we reflect on commonalities and discrepancies among studies and on the genetic or somatic conditions that may cause this schism in cancer behavior.

CXCR3/CCR5 pathways in metastatic melanoma patients treated with adoptive therapy and interleukin-2

Background:Adoptive therapy with tumour-infiltrating lymphocytes (TILs) induces durable complete responses (CR) in ∼20% of patients with metastatic melanoma. The recruitment of T cells through CXCR3/CCR5 chemokine ligands is critical for immune-mediated rejection. We postulated that polymorphisms and/or expression of CXCR3/CCR5 in TILs and the expression of their ligands in tumour influence the migration of TILs to tumours and tumour regression.Methods:Tumour-infiltrating lymphocytes from 142 metastatic melanoma patients enrolled in adoptive therapy trials were genotyped for CXCR3 rs2280964 and CCR5-Δ32 deletion, which encodes a protein not expressed on the cell surface. Expression of CXCR3/CCR5 in TILs and CXCR3/CCR5 and ligand genes in 113 available parental tumours was also assessed. Tumour-infiltrating lymphocyte data were validated by flow cytometry (N=50).Results:The full gene expression/polymorphism model, which includes CXCR3 and CCR5 expression data, CCR5-Δ32 polymorphism data and their interaction, was significantly associated with both CR and overall response (OR; P=0.0009, and P=0.007, respectively). More in detail, the predicted underexpression of both CXCR3 and CCR5 according to gene expression and polymorphism data (protein prediction model, PPM) was associated with response to therapy (odds ratio=6.16 and 2.32, for CR and OR, respectively). Flow cytometric analysis confirmed the PPM. Coordinate upregulation of CXCL9, CXCL10, CXCL11, and CCL5 in pretreatment tumour biopsies was associated with OR.Conclusion:Coordinate overexpression of CXCL9, CXCL10, CXCL11, and CCL5 in pretreatment tumours was associated with responsiveness to treatment. Conversely, CCR5-Δ32 polymorphism and CXCR3/CCR5 underexpression influence downregulation of the corresponding receptors in TILs and were associated with likelihood and degree of response.

Melanoma NOS1 expression promotes dysfunctional IFN signaling

In multiple forms of cancer, constitutive activation of type I IFN signaling is a critical consequence of immune surveillance against cancer; however, PBMCs isolated from cancer patients exhibit depressed STAT1 phosphorylation in response to IFN-α, suggesting IFN signaling dysfunction. Here, we demonstrated in a coculture system that melanoma cells differentially impairs the IFN-α response in PBMCs and that the inhibitory potential of a particular melanoma cell correlates with NOS1 expression. Comparison of gene transcription and array comparative genomic hybridization (aCGH) between melanoma cells from different patients indicated that suppression of IFN-α signaling correlates with an amplification of the NOS1 locus within segment 12q22-24. Evaluation of NOS1 levels in melanomas and IFN responsiveness of purified PBMCs from patients indicated a negative correlation between NOS1 expression in melanomas and the responsiveness of PBMCs to IFN-α. Furthermore, in an explorative study, NOS1 expression in melanoma metastases was negatively associated with patient response to adoptive T cell therapy. This study provides a link between cancer cell phenotype and IFN signal dysfunction in circulating immune cells.

Genomic scale analysis of racial impact on response to IFN-α

Limited responsiveness to IFN-α in hepatitis C virus (HCV)-infected African-Americans compared to European Americans (AAs vs. EAs) hinders the management of HCV. Here, we studied healthy non-HCV-infected AA and EA subjects to test whether immune cell response to IFN-α is determined directly by race. We compared baseline and IFN-α-induced signal transducer and activator of transcription (STAT)-1, STAT-2, STAT-3, STAT-4, and STAT-5 protein and phosphorylation levels in purified T cells, global transcription, and a genomewide single-nucleotide polymorphism (SNP) profile of healthy AA and EA blood donors. In contrast to HCV-infected individuals, healthy AAs displayed no evidence of reduced STAT activation or IFN-α-stimulated gene expression compared to EAs. Although >200 genes reacted to IFN-α treatment, race had no impact on any of them. The only gene differentially expressed by the two races (NUDT3, P < 10−7) was not affected by IFN-α and bears no known relationship to IFN-α signaling or HCV pathogenesis. Genomewide analysis confirmed the self-proclaimed racial attribution of most donors, and numerous race-associated SNPs were identified within loci involved in IFN-α signaling, although they clearly did not affect responsiveness in the absence of HCV. We conclude that racial differences observed in HCV-infected patients in the responsiveness to IFN-α are unrelated to inherent racial differences in IFN-α signaling and more likely due to polymorphisms affecting the hosts’ response to HCV, which in turn may lead to a distinct disease pathophysiology responsible for altered IFN signaling and treatment response.

Tumor-Associated Inflammation and Impact on Dendritic Cell Function

Tumor-associated inflammation is a frequently observed phenomenon considered to be one of the major hallmarks of neoplastic disease progression. Recent data show that inflammatory processes around malignancies are able to both support and suppress neoplastic progression depending on the phase of tumor progression or the cytokine context of ongoing immunological processes in the tumor microenvironment. Recent concepts of malignancy-associated inflammation and its impact on dendritic cell functions suggest that the net effect of inflammation on the balance between tumor growth and dendritic cell-controlled immunity is continuously changing over time, as inflammatory signals are frequently re-interpreted along with cancer progression. Initially, inflammation sustains malignant conversion and supports survival of tumor cells in cryptic cancers; however, it also allows their recognition by dendritic cells via damage-associated molecular patterns. In progressing cancers, inflammation contributes to malignant invasion, angiogenesis, and metastasis formation. In addition, via suppressing dendritic cell activation, maturation, and disrupting communication between dendritic cells and NK or T cells, it also corrupts antitumor immune responses launched by both the innate and adaptive immune systems. On the other hand, upon appropriate stimulation of specific toll-like receptors, tumor-infiltrating myeloid and plasmacytoid dendritic cells can be successfully activated, leading to harsh inflammatory reactions ultimately resulting in rapid rejection of tumor cells. Thus, ubiquitous presence of inflammation around tumors can be exploited not only for early detection of cryptic malignant lesions but also for inducing dendritic cell-mediated rejection of established malignancies.

Longitudinal Study of Recurrent Metastatic Melanoma Cell Lines Underscores the Individuality of Cancer Biology

Recurrent metastatic melanoma provides a unique opportunity to analyze disease evolution in metastatic cancer. Here, we followed 8 patients with an unusually prolonged history of metastatic melanoma, who developed a total of 26 recurrences over several years. Cell lines derived from each metastasis were analyzed by comparative genomic hybridization and global transcript analysis. We observed that conserved, patient-specific characteristics remain stable in recurrent metastatic melanoma even after years and several recurrences. Differences among individual patients exceeded within-patient lesion variability, both at the DNA copy number (p<0.001) and RNA gene expression level (p<0.001). Conserved patient-specific traits included expression of several cancer/testis antigens and the c-kit proto-oncogene throughout multiple recurrences. Interestingly, subsequent recurrences of different patients did not display consistent or convergent changes toward a more aggressive disease phenotype. Finally, sequential recurrences of the same patient did not descend progressively from each other, as irreversible mutations, such as homozygous deletions were frequently not inherited from previous metastases. This study suggests that the late evolution of metastatic melanoma, which dramatically turns an indolent disease into a lethal phase, is prone to preserve case-specific traits over multiple recurrences and occurs through a series of random events that do not follow a consistent step-wise process.