Markers of T cell infiltration and function associate with favorable outcome in vascularized high-grade serous ovarian carcinoma

High-risk patient profiles for ovarian cancer: A new approach using cluster analysis of tumor markers

OBJECTIVE

Ovarian cancer remains a leading cause of cancer-related deaths in women. Early detection improves prognosis, but current diagnostic tools still need improvement. We aimed to identify high-risk patient profiles for ovarian cancer using cluster analysis of age and tumor marker data.

MATERIAL AND METHODS

A secondary dataset analysis was conducted using unsupervised learning techniques. Data were from a University Hospital, originally collected between July 2011 and July 2018 in Taiwan. In total, 349 women diagnosed with ovarian masses, including both benign and malignant tumors, were included in this analysis. The median age was 45 years, and 49 % were diagnosed with ovarian cancer in pathology. We used a hierarchical clustering algorithm to find groups of patients with similar features.

RESULTS

Two clusters were identified (N = 204 and 145), with a high-risk cluster (66.2 % malignancy) characterized by significantly older age, higher CA125, HE4, CEA, and AFP levels, and a lower CA19-9 level than the low-risk cluster (24.8 % malignancy). The assessment of clustering stability and internal validity yielded a figure of merit score of 0.970 and a silhouette coefficient of 0.524. A classification model using age, CA125, HE4, and CA19-9 demonstrated high accuracy (89.4 %), sensitivity (94.5 %), specificity (83.7 %), and a large area under the curve (89.1 %) for the risk stratification.

CONCLUSION

Integrating tumor markers with patient demographics improved the differentiation between benign and malignant ovarian masses. This approach can help clinicians prioritize high-risk patients for further diagnostic evaluation and reduce unnecessary invasive procedures for low-risk patients.

A novel serous ovarian carcinoma model induced by DMBA: Results from OncoTherad® (MRB-CFI-1) immunotherapy preclinical testing

AIMS

The term ovarian carcinoma (OC) refers to a heterogeneous collection of five distinct diseases known as histotypes. While histotype-specific treatment is still a clinical challenge in OC, well-characterized models are required for testing new therapeutic strategies. We employed OncoTherad® (MRB-CFI-1), an interferon (IFN-γ)-stimulating nano-immunotherapy mediated by Toll-like receptors (TLR) 2/4, in association or not with Erythropoietin (EPO) in a chemically-induced ovarian cancer model. Besides characterization of the therapies effects, we also assessed whether the animal model was representative of human OC by providing histotype classification.

MAIN METHODS

Thirty-five Fischer rats were distributed into five groups: Control (Sham surgery); Cancer (7,12-dimethylbenzoanthracene - DMBA injection in the ovarian bursa, 1.25 mg/kg); OncoTherad® (20 mg/kg intraperitoneal); EPO (8.4 µg/kg intraperitoneal); and OncoTherad+EPO (same doses). Ovaries were formalin-fixed into paraffin-embedded blocks. TLR pathway and the inflammatory response profile were evaluated by immunohistochemistry (IHC). After DNA extraction and tissue microarray construction, we assessed typical gene mutations directly (Sanger sequencing) or indirectly (IHC surrogates) and examined biomarkers of different OC histotypes.

KEY FINDINGS

OC induction decreased TLR2, TLR4, and proinflammatory cytokines. OncoTherad® alone or associated with EPO modulated the OC microenvironment to a cytotoxic immune profile through stimulation of the TLR4-mediated non-canonical pathway. EPO stimulated TLR2-mediated canonical pathway and notably increased Tregs.

SIGNIFICANCE

The features analyzed favored interpretation of our DMBA-induced tumor model as predominantly low-grade, serous carcinoma-like, in which treatments with OncoTherad® and EPO showed immunomodulatory properties related to the reduction of ovarian lesions.

Mechanisms of HIF1A-mediated immune evasion in gastric cancer and the impact on therapy resistance

BACKGROUND

The high prevalence and detrimental effects on patient outcomes make gastric cancer (GC) a significant health issue that persists internationally. Existing treatment modalities exhibit limited efficacy, prompting the exploration of immune checkpoint inhibitors as a novel therapeutic approach. However, resistance to immunotherapy poses a significant challenge in GC management, necessitating a profound grasp of the intrinsic molecular pathways.

METHODS

This study focuses on investigating the immunosuppressive mechanisms of quiescent cancer cells (QCCs) in GC, particularly their resistance to T-cell-mediated immune responses. Utilizing mouse models, gene editing techniques, and transcriptome sequencing, we aim to elucidate the interactions between QCCs, immune cells, and key regulatory factors like HIF1A. Functional enrichment analysis will further underscore the role of glycolysis-related genes in mediating immunosuppression by QCCs.

RESULTS

The cancer cells that survived GC treated with T-cell therapy lost their proliferative ability. QCCs, as the main resistance force to immunotherapy, exhibit stronger resistance to CD8+ T-cell attack and possess higher cancer-initiating potential. Single-cell sequencing analysis revealed that the microenvironment in the QCCs region harbors more M2-type tumor-associated macrophages and fewer T cells. This microenvironment in the QCCs region leads to the downregulation of T-cell immune activation and alters macrophage metabolic function. Transcriptome sequencing of QCCs identified upregulated genes related to chemo-resistance, hypoxia, and glycolysis. In vitro cell experiments illustrated that HIF1A promotes the transcription of glycolysis-related genes, and silencing HIF1A in QCCs enhances T-cell proliferation and activation in co-culture systems, induces apoptosis in QCCs, and increases QCCs' sensitivity to immune checkpoint inhibitors. In vivo, animal experiments showed that silencing HIF1A in QCCs can inhibit GC growth and metastasis.

CONCLUSION

Unraveling the molecular mechanisms by which QCCs resist T-cell-mediated immune responses through immunosuppression holds promising implications for refining treatment strategies and enhancing patient outcomes in GC. By delineating these intricate interactions, this study contributes crucial insights into precision medicine and improved therapeutic outcomes in GC management.

CD8 + T cell infiltration is associated with improved survival and negatively correlates with hypoxia in clear cell ovarian cancer

Unlike other histological types of epithelial ovarian carcinoma, clear cell ovarian carcinoma (CCOC) has poor response to therapy. In many other carcinomas, expression of the hypoxia-related enzyme Carbonic anhydrase IX (CAIX) by cancer cells is associated with poor prognosis, while the presence of CD8 + tumor-infiltrating lymphocytes (TIL) is positively prognostic. We employed [¹⁸F]EF5-PET/CT imaging, transcriptome profiling, and spatially-resolved histological analysis to evaluate relationships between CAIX, CD8, and survival in CCOC. Tissue microarrays (TMAs) were evaluated for 218 cases in the Canadian COEUR study. Non-spatial relationships between CAIX and CD8 were investigated using Spearman rank correlation, negative binomial regression and gene set enrichment analysis. Spatial relationships at the cell level were investigated using the cross K-function. Survival analysis was used to assess the relationship of CAIX and CD8 with patient survival for 154 cases. CD8 + T cell infiltration positively predicted survival with estimated hazard ratio 0.974 (95% CI 0.950, 1000). The negative binomial regression analysis found a strong TMA effect (p-value < 0.0001). It also indicated a negative association between CD8 and CAIX overall (p-value = 0.0171) and in stroma (p-value = 0.0050) but not in tumor (p-value = 0.173). Examination of the spatial association between the locations of CD8 + T cells and CAIX cells found a significant amount of heterogeneity in the first TMA, while in the second TMA there was a clear signal indicating negative spatial association in stromal regions. These results suggest that hypoxia may contribute to immune exclusion, primarily mediated by effects in stroma.

Regulation of autophagy fires up the cold tumor microenvironment to improve cancer immunotherapy

Immunotherapies, such as immune checkpoint inhibitors (ICIs) and chimeric antigen receptor (CAR) T cells, have revolutionized the treatment of patients with advanced and metastatic tumors resistant to traditional therapies. However, the immunosuppressed tumor microenvironment (TME) results in a weak response to immunotherapy. Therefore, to realize the full potential of immunotherapy and obstacle barriers, it is essential to explore how to convert cold TME to hot TME. Autophagy is a crucial cellular process that preserves cellular stability in the cellular components of the TME, contributing to the characterization of the immunosuppressive TME. Targeted autophagy ignites immunosuppressive TME by influencing antigen release, antigen presentation, antigen recognition, and immune cell trafficking, thereby enhancing the effectiveness of cancer immunotherapy and overcoming resistance to immunotherapy. In this review, we summarize the characteristics and components of TME, explore the mechanisms and functions of autophagy in the characterization and regulation of TME, and discuss autophagy-based therapies as adjuvant enhancers of immunotherapy to improve the effectiveness of immunotherapy.

Hypoxia induces HIF1α-dependent epigenetic vulnerability in triple negative breast cancer to confer immune effector dysfunction and resistance to anti-PD-1 immunotherapy

The hypoxic tumor microenvironment has been implicated in immune escape, but the underlying mechanism remains elusive. Using an in vitro culture system modeling human T cell dysfunction and exhaustion in triple-negative breast cancer (TNBC), we find that hypoxia suppresses immune effector gene expression, including in T and NK cells, resulting in immune effector cell dysfunction and resistance to immunotherapy. We demonstrate that hypoxia-induced factor 1α (HIF1α) interaction with HDAC1 and concurrent PRC2 dependency causes chromatin remolding resulting in epigenetic suppression of effector genes and subsequent immune dysfunction. Targeting HIF1α and the associated epigenetic machinery can reverse the immune effector dysfunction and overcome resistance to PD-1 blockade, as demonstrated both in vitro and in vivo using syngeneic and humanized mice models. These findings identify a HIF1α-mediated epigenetic mechanism in immune dysfunction and provide a potential strategy to overcome immune resistance in TNBC.

Hypoxia can promote tumor escape from immune surveillance and immunotherapy. Here, the authors show that hypoxia induces T and NK cell dysfunction through HIF1α-mediated epigenetic suppression of effector gene expression, conferring resistance to anti-PD1 blockade in triple negative breast cancer models.

1-Methylnicotinamide is an immune regulatory metabolite in human ovarian cancer

Immune regulatory metabolites are key features of the tumor microenvironment (TME), yet with a few exceptions, their identities remain largely unknown. Here, we profiled tumor and T cells from tumor and ascites of patients with high-grade serous carcinoma (HGSC) to uncover the metabolomes of these distinct TME compartments. Cells within the ascites and tumor had pervasive metabolite differences, with a notable enrichment in 1-methylnicotinamide (MNA) in T cells infiltrating the tumor compared with ascites. Despite the elevated levels of MNA in T cells, the expression of nicotinamide N-methyltransferase, the enzyme that catalyzes the transfer of a methyl group from S-adenosylmethionine to nicotinamide, was restricted to fibroblasts and tumor cells. Functionally, MNA induces T cells to secrete the tumor-promoting cytokine tumor necrosis factor alpha. Thus, TME-derived MNA contributes to the immune modulation of T cells and represents a potential immunotherapy target to treat human cancer.

Modeling of the immune response in the pathogenesis of solid tumors and its prognostic significance

BACKGROUND

Tumor initiation and subsequent progression are usually long-term processes, spread over time and conditioned by diverse aspects. Many cancers develop on the basis of chronic inflammation; however, despite dozens of years of research, little is known about the factors triggering neoplastic transformation under these conditions. Molecular characterization of both pathogenetic states, i.e., similarities and differences between chronic inflammation and cancer, is also poorly defined. The secretory activity of tumor cells may change the immunophenotype of immune cells and modify the extracellular microenvironment, which allows the bypass of host defense mechanisms and seems to have diagnostic and prognostic value. The phenomenon of immunosuppression is also present during chronic inflammation, and the development of cancer, due to its duration, predisposes patients to the promotion of chronic inflammation. The aim of our work was to discuss the above issues based on the latest scientific insights. A theoretical mechanism of cancer immunosuppression is also proposed.

CONCLUSIONS

Development of solid tumors may occur both during acute and chronic phases of inflammation. Differences in the regulation of immune responses between precancerous states and the cancers resulting from them emphasize the importance of immunosuppressive factors in oncogenesis. Cancer cells may, through their secretory activity and extracellular transport mechanisms, enhance deterioration of the immune system which, in turn, may have prognostic implications.

Longitudinal imaging of T cell-based immunotherapy with multi-spectral, multi-scale optoacoustic tomography

Most imaging studies of immunotherapy have focused on tracking labeled T cell biodistribution in vivo for understanding trafficking and homing parameters and predicting therapeutic efficacy by the presence of transferred T cells at or in the tumour mass. Conversely, we investigate here a novel concept for longitudinally elucidating anatomical and pathophysiological changes of solid tumours after adoptive T cell transfer in a preclinical set up, using previously unexplored in-tandem macroscopic and mesoscopic optoacoustic (photoacoustic) imaging. We show non-invasive in vivo observations of vessel collapse during tumour rejection across entire tumours and observe for the first time longitudinal tumour rejection in a label-free manner based on optical absorption changes in the tumour mass due to cellular decline. We complement these observations with high resolution episcopic fluorescence imaging of T cell biodistribution using optimized T cell labeling based on two near-infrared dyes targeting the cell membrane and the cytoplasm. We discuss how optoacoustic macroscopy and mesoscopy offer unique contrast and immunotherapy insights, allowing label-free and longitudinal observations of tumour therapy. The results demonstrate optoacoustic imaging as an invaluable tool in understanding and optimizing T cell therapy.

Seven Genes Based Novel Signature Predicts Clinical Outcome and Platinum Sensitivity of High Grade IIIc Serous Ovarian Carcinoma

Background: As a major subtype of ovarian cancer, high grade FIGO stage IIIc serous ovarian carcinoma (HG3cSOC), has various prognosis due to genetic heterogeneity.

Methods: The transcriptome of 401 primary FIGO IIIc serous ovarian samples was screened, seven genes based prognostic model was developed. The prognostic valueof risk score in four different cohorts (TCGA-cohort, Poland-cohort, Japan-cohort and USA-cohort) was validated. The relationship between risk score and other clinical indicators were analyzed. The guide value of risk score for platinum-taxol chemotherapy was also assayed. Tissue microenvironment difference among samples with different risk scores was investigated.

Results: High-risk group (N=200, median survival months: 39.6, 95% CI: 35.9-46.3 months) had a significantly worse prognosis than low-risk group (N=201, median survival months: 52.6, 95% CI: 45.2-64.9 months;). The risk score's performance was validated in Japan-cohort (N=90, Poland-cohort (N=48) and USA-cohort (N=84). The risk score is independent from age, primary tumor size, grade and treatment methods and the performance of risk score is uniform in subgroups. Furthermore, the risk score predicted the response of HG3cSOC to platinum-based regimen after surgery, and this finding was further validated in newly collected China-cohort (N=102). Gene Set Enrichment Analysis (GSEA) and tumor infiltration analysis revealed that risk score reflected the immune infiltration and cell-cell interaction status, and the migration function of candidate genes were also verified.

Conclusions: The optimized seven genes-based model is a valuable and robust model in predicting the survival of HG3cSOC, and served as a valuable marker for the response to platinum-based chemotherapy.

A computational framework for complex disease stratification from multiple large-scale datasets

BACKGROUND

Multilevel data integration is becoming a major area of research in systems biology. Within this area, multi-'omics datasets on complex diseases are becoming more readily available and there is a need to set standards and good practices for integrated analysis of biological, clinical and environmental data. We present a framework to plan and generate single and multi-'omics signatures of disease states.

METHODS

The framework is divided into four major steps: dataset subsetting, feature filtering, 'omics-based clustering and biomarker identification.

RESULTS

We illustrate the usefulness of this framework by identifying potential patient clusters based on integrated multi-'omics signatures in a publicly available ovarian cystadenocarcinoma dataset. The analysis generated a higher number of stable and clinically relevant clusters than previously reported, and enabled the generation of predictive models of patient outcomes.

CONCLUSIONS

This framework will help health researchers plan and perform multi-'omics big data analyses to generate hypotheses and make sense of their rich, diverse and ever growing datasets, to enable implementation of translational P4 medicine.

How can molecular abnormalities influence our clinical approach

Background

Despite improvements in diagnostics and treatment, the clinical outcome of epithelial ovarian cancer remains poor over the last three decades. Recent high-throughput genomic studies have demonstrated ovarian cancer as a highly heterogeneous entity with distinctive molecular signatures among different or even within the same histotype. In this article, we review the molecular genetics of epithelial ovarian cancer and how they have been translated into modern clinical trials, as well as their implications in patient stratification for more targeted and personalized approaches.

Patients and methods

Multiple genomic studies were collected to summarize the major advances in understanding ovarian cancer-associated molecular abnormalities with emphasis on their potential clinical applicability to rationalize the design of recent clinical trials.

Results

The clinical management of ovarian cancer can significantly benefit from comprehensive molecular profiling studies, which have uncovered the distinctiveness of ovarian cancer subsets bearing characteristic genomic aberrance and consequentially dysregulated genes and pathways underlying the tumor progression and chemoresistance. Genomics studies have demonstrated a powerful tool to delineate the molecular basis responsible for diverse clinical behaviors associated with tumor histology and grade. In addition, molecular signatures obtained by integrated 'omics' analyses have promised opportunities for novel therapeutic or stratification biomarkers to tailor current clinical management as well as novel predictive tools of clinical end points including patient prognosis and therapeutic efficacy.

Conclusions

Recent progress in understanding the molecular landscape of ovarian cancer has profoundly shifted the design of clinical trials from empirical, unitary paradigms to more rationalized and personalized regimes. Correspondingly, a promising prospective has emerged for ovarian cancer patients to have considerably improved outcome upon careful alignment of patient characteristics, therapeutic biomarkers and targeting approaches. Nevertheless, extensive validation and inference of potential biomarkers are pressing demands on both bioinformatic and biological levels to warrant sufficient clinical relevance for potential translation, so that the performance of related clinical trial can be well predicted and achieved.

Immune evasion mechanisms and immune checkpoint inhibition in advanced merkel cell carcinoma

Merkel cell carcinoma (MCC) is a rare skin cancer caused by Merkel cell polyomavirus (MCPyV) infection and/or ultraviolet radiation-induced somatic mutations. The presence of tumor-infiltrating lymphocytes is evidence that an active immune response to MCPyV and tumor-associated neoantigens occurs in some patients. However, inhibitory immune molecules, including programmed death-1 (PD-1) and programmed death-ligand 1 (PD-L1), within the MCC tumor microenvironment aid in tumor evasion of T-cell-mediated clearance. Unlike chemotherapy, treatment with anti-PD-L1 (avelumab) or anti-PD-1 (pembrolizumab) antibodies leads to durable responses in MCC, in both virus-positive and virus-negative tumors. As many tumors are established through the evasion of infiltrating immune-cell clearance, the lessons learned in MCC may be broadly relevant to many cancers.

Whence High-Grade Serous Ovarian Cancer

Our understanding of epithelial ovarian cancer has blossomed, and we now recognize that it is a collection of varied histologic and molecularly different malignancies, many of which may not derive from a true ovarian anatomic precursor. High-grade serous ovarian cancer (HGSOC) is a unique type of epithelial cancer. It is characterized by nearly universal mutation in and dysfunction of p53, genomic instability rather than driver mutations, advanced stage at onset, and probable fallopian tube epithelium origin, with a serous tubal in situ carcinoma precursor. Germline deleterious mutations in BRCA1 and BRCA2, as well as other less prevalent genes involved in DNA repair, such as PALB2 and RAD51c, are associated with its carcinogenesis and may predict susceptibility to classes of treatment agents, including DNA-damaging agents and DNA repair inhibitors. Loss of function of these genes is associated with homologous recombination dysfunction (HRD). It is now recognized that there may be HGSOC with wild-type BRCA1 and BRCA2 with an identifiable HRD phenotype. Such HRD tumors also may be more susceptible to certain classes of treatments and may be phenotypically detectable with a composite molecular biomarker that has been shown to be predictive for response to PARP inhibitors. Use of this new knowledge of the anatomic and molecular background of HGSOC has led to the rational design of novel combinations of treatment classes to create an HRD-like cellular environment and thus drive treatment benefits.

Prognostic Value of Programmed Death Ligand 1 and Programmed Death 1 Expression in Thymic Carcinoma

PURPOSE

The immune checkpoint of the programmed death 1/programmed death ligand 1 (PD-1/PD-L1) pathway is believed to play an important role in evasion of host antitumor immune surveillance in various malignancies; however, little is known about its role in thymic carcinoma. This study investigated PD-1/PD-L1 expression and its association with clinicopathologic features, the expression of immune-related proteins in tumor-infiltrating lymphocytes (TIL), and patient prognosis.

EXPERIMENTAL DESIGN

PD-L1 and PD-1 expression was evaluated by IHC in 25 thymic carcinoma tissue specimens. Copy number alterations of the PD-L1 gene in 11 cases were assessed in formalin-fixed, paraffin-embedded material using qRT-PCR.

RESULTS

Compared with normal subjects, 3 thymic carcinoma patients showed an increase in PD-L1 copy number, whereas 8 did not. PD-L1 was significantly overexpressed in cases with copy number gain as compared with normal cases. High PD-L1 expression was associated with higher disease-free and overall survival rates as compared to cases with low expression. Prognostic analysis revealed low PD-L1 expression and high number of PD-1(+) TILs as significant predictors of poor survival, together with Masaoka-Koga stage IVa/IVb disease and incomplete resection. In the quantitative analysis of TILs, PD-L1 expression correlated proportionally with the number of infiltrating CTLs.

CONCLUSIONS

Here, for the first time, we report that PD-L1 and PD-1 expression might be useful prognostic predictors in thymic carcinoma. Further studies are expected to substantiate the prognostic value of PD-L1 and PD-1 expression, and the potential efficacy of targeting the PD-1/PD-L1 pathway in thymic carcinoma via immunotherapy. Clin Cancer Res; 22(18); 4727-34. ©2016 AACR.

T-cell intracellular antigens in health and disease

T-cell intracellular antigen 1 (TIA1) and TIA1-related/like protein (TIAR/TIAL1) are 2 proteins discovered in 1991 as components of cytotoxic T lymphocyte granules. They act in the nucleus as regulators of transcription and pre-mRNA splicing. In the cytoplasm, TIA1 and TIAR regulate and/or modulate the location, stability and/or translation of mRNAs. As knowledge of the different genes regulated by these proteins and the cellular/biological programs in which they are involved increases, it is evident that these antigens are key players in human physiology and pathology. This review will discuss the latest developments in the field, with physiopathological relevance, that point to novel roles for these regulators in the molecular and cell biology of higher eukaryotes.

Radiation-Induced Glycogen Accumulation Detected by Single Cell Raman Spectroscopy Is Associated with Radioresistance that Can Be Reversed by Metformin

Altered cellular metabolism is a hallmark of tumor cells and contributes to a host of properties associated with resistance to radiotherapy. Detection of radiation-induced biochemical changes can reveal unique metabolic pathways affecting radiosensitivity that may serve as attractive therapeutic targets. Using clinically relevant doses of radiation, we performed label-free single cell Raman spectroscopy on a series of human cancer cell lines and detected radiation-induced accumulation of intracellular glycogen. The increase in glycogen post-irradiation was highest in lung (H460) and breast (MCF7) tumor cells compared to prostate (LNCaP) tumor cells. In response to radiation, the appearance of this glycogen signature correlated with radiation resistance. Moreover, the buildup of glycogen was linked to the phosphorylation of GSK-3β, a canonical modulator of cell survival following radiation exposure and a key regulator of glycogen metabolism. When MCF7 cells were irradiated in the presence of the anti-diabetic drug metformin, there was a significant decrease in the amount of radiation-induced glycogen. The suppression of glycogen by metformin following radiation was associated with increased radiosensitivity. In contrast to MCF7 cells, metformin had minimal effects on both the level of glycogen in H460 cells following radiation and radiosensitivity. Our data demonstrate a novel approach of spectral monitoring by Raman spectroscopy to assess changes in the levels of intracellular glycogen as a potential marker and resistance mechanism to radiation therapy.

Cancer vaccines

Cancer vaccines are designed to promote tumor specific immune responses, particularly cytotoxic CD8 positive T cells that are specific to tumor antigens. The earliest vaccines, which were developed in 1994-95, tested non-mutated, shared tumor associated antigens that had been shown to be immunogenic and capable of inducing clinical responses in a minority of people with late stage cancer. Technological developments in the past few years have enabled the investigation of vaccines that target mutated antigens that are patient specific. Several platforms for cancer vaccination are being tested, including peptides, proteins, antigen presenting cells, tumor cells, and viral vectors. Standard of care treatments, such as surgery and ablation, chemotherapy, and radiotherapy, can also induce antitumor immunity, thereby having cancer vaccine effects. The monitoring of patients' immune responses at baseline and after standard of care treatment is shedding light on immune biomarkers. Combination therapies are being tested in clinical trials and are likely to be the best approach to improving patient outcomes.

New insights into tumor immunity revealed by the unique genetic and genomic aspects of ovarian cancer

Ovarian cancer is a challenging disease that nonetheless provokes brisk, prognostically favorable immune responses in many patients. The biology of ovarian cancer offers unique insights into the factors that engender protective tumor immunity. Tumor-infiltrating lymphocyte (TIL) patterns range from CD8+ TIL alone to complex aggregates that additionally include CD4+ and CD20+ TIL. Patient survival rates increase in step with TIL complexity, suggesting cooperative interactions between these lymphocyte subsets. TIL are associated with high-grade serous histology and BRCA1 disruption; the latter may promote immunity through altered cytokine signaling, oxidative stress responses, or antigen expression. The ovarian tumor genome demonstrates extensive spatial and temporal heterogeneity, yet TIL exhibit relatively homogeneous spatial distributions that may reflect core properties of the tumor. In summary, ovarian cancer attracts the attention of the immune system in ways that create unique challenges and opportunities for immunotherapy.

Elucidating immunologic mechanisms of PROSTVAC cancer immunotherapy

BACKGROUND

PROSTVAC®, an active immunotherapy currently studied for the treatment of metastatic castration-resistant prostate cancer (mCRPC), consists of a heterologous prime-boost regimen with two different poxvirus-based vectors to provoke productive immune responses against prostate specific antigen (PSA) as the target tumor antigen. A Phase 2 study of PROSTVAC immunotherapy showed significantly improved median overall survival by 8.5 months and is currently being validated in a global Phase 3 study (PROSPECT; NCT01322490). Here, preclinical models were explored to investigate the mechanism of action and immune signatures of anti-tumor efficacy with PROSTVAC immunotherapy with the goal to identify potential immune correlates of clinical benefit.

METHODS

PROSTVAC-induced immune responses and anti-tumor efficacy were studied in male BALB/c mice. Functionality of the induced T cell response was characterized by interferon-gamma (IFNγ) ELISPOT, cytotoxic degranulation, multi-cytokine intracellular staining, and in vivo T cell depletion. Tumor infiltrating lymphocytes (TILs) were evaluated phenotypically by flow cytometry.

RESULTS

The heterologous prime-boost regimen of the two PROSTVAC vectors significantly enhanced the magnitude and quality of activated PSA-specific CD4 and CD8 T cell responses compared to homologous, single vector regimens. PROSTVAC-activated CD4 and CD8 T cells were highly functional as evidenced by expression of activation markers, production of multiple cytokines, and amplified cytotoxic T cell activity. Importantly, PROSTVAC immunotherapy resulted in significant anti-tumor efficacy in a transplantable prostate cancer mouse model. Antigen-spreading occurred in PROSTVAC-treated animals that rejected PSA-expressing tumors, as shown by subsequent rejection of PSA-negative tumors. In vivo CD4 and CD8 depletion revealed that both T cell subsets contributed to anti-tumor efficacy. Characterization of TILs demonstrated that PROSTVAC immunotherapy greatly increased the intra-tumoral ratio of activated effector to regulatory T cells.

CONCLUSIONS

PROSTVAC immunotherapy activates broad, highly functional T cell immunity to PSA and to endogenous tumor antigens via immune-mediated antigen spreading. These preclinical results further elucidate the mode of action of PROSTVAC immunotherapy and its potential causal relationship to extended overall survival as observed in the PROSTVAC Phase 2 study. The clinical validation is ongoing in the PROSPECT Phase 3 clinical study.

CD8+ lymphocyte intratumoral infiltration as a stage-independent predictor of Merkel cell carcinoma survival: a population-based study

OBJECTIVES

Intratumoral CD8+ lymphocytes (IT-CD8s) have shown promise as a prognostic indicator for Merkel cell carcinoma (MCC). We tested whether IT-CD8s predict survival among a population-based MCC cohort.

METHODS

One hundred thirty-seven MCC cases that had not previously been analyzed for IT-CD8s were studied.

RESULTS

Three-year MCC-specific survival rates were 56%, 72%, and 100% for patients with absent (n = 46), low (n = 85), and moderate or strong (n = 6) IT-CD8s, respectively. Increased IT-CD8s were associated with improved MCC-specific survival in a multivariate competing risk-regression analysis including stage, age, and sex (hazard ratio [HR] = 0.5; 95% confidence interval [CI] = 0.3-0.9). Although a similar trend was observed for overall survival, statistical significance was not reached (HR = 0.8; 95% CI = 0.6-1.0), likely because of the high rate of non-MCC deaths among older patients.

CONCLUSIONS

This study of prospectively captured MCC cases supports the concept that cellular immunity is important in MCC outcome and that CD8+ lymphocyte infiltration adds prognostic information to conventional staging.

Threonyl-tRNA synthetase overexpression correlates with angiogenic markers and progression of human ovarian cancer

Background

Ovarian tumors create a dynamic microenvironment that promotes angiogenesis and reduces immune responses. Our research has revealed that threonyl-tRNA synthetase (TARS) has an extracellular angiogenic activity separate from its function in protein synthesis. The objective of this study was to test the hypothesis that TARS expression in clinical samples correlates with angiogenic markers and ovarian cancer progression.

Methods

Protein and mRNA databases were explored to correlate TARS expression with ovarian cancer. Serial sections of paraffin embedded ovarian tissues from 70 patients diagnosed with epithelial ovarian cancer and 12 control patients were assessed for expression of TARS, vascular endothelial growth factor (VEGF) and PECAM using immunohistochemistry. TARS secretion from SK-OV-3 human ovarian cancer cells was measured. Serum samples from 31 tissue-matched patients were analyzed by ELISA for TARS, CA-125, and tumor necrosis factor-α (TNF-α).

Results

There was a strong association between the tumor expression of TARS and advancing stage of epithelial ovarian cancer (p < 0.001). TARS expression and localization were also correlated with VEGF (p < 0.001). A significant proportion of samples included heavy TARS staining of infiltrating leukocytes which also correlated with stage (p = 0.017). TARS was secreted by ovarian cancer cells, and patient serum TARS was related to tumor TARS and angiogenic markers, but did not achieve significance with respect to stage. Multivariate Cox proportional hazard models revealed a surprising inverse relationship between TARS expression and mortality risk in late stage disease (p = 0.062).

Conclusions

TARS expression is increased in epithelial ovarian cancer and correlates with markers of angiogenic progression. These findings and the association of TARS with disease survival provide clinical validation that TARS is associated with angiogenesis in ovarian cancer. These results encourage further study of TARS as a regulator of the tumor microenvironment and possible target for diagnosis and/or treatment in ovarian cancer.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2407-14-620) contains supplementary material, which is available to authorized users.

Tumor vascularity in ovarian cancer: T cells need breathing room

Tumor-infiltrating lymphocytes (TILs) are crucial for effective antitumor responses. However, hypoxia can skew T-cell differentiation and function, thereby perturbing TILs. We have demonstrated that TILs and their immune function are associated with tumor vascularization. These features are prognostic for improved disease-specific survival in ovarian cancer. Thus, new immunotherapies should consider how hypoxia impacts antitumor immunity.