High density of CXCL12-positive immune cell infiltration predicts chemosensitivity and recurrence-free survival in ovarian carcinoma

BACKGROUND

Ovarian carcinoma is the most lethal gynecologic malignancy because of its late diagnosis, extremely high recurrence rate, and limited curative treatment options. In clinical practice, high-grade serous carcinoma (HGSC) predominates due to its frequency, high aggressiveness, and rapid development of drug resistance. Recent evidence suggests that CXCL12 is an important immunological factor in ovarian cancer progression. Therefore, we investigated the predictive and prognostic significance of the expression of this chemokine in tumor and immune cells in patients with HGSC.

METHODS

We studied a cohort of 47 primary high-grade serous ovarian carcinomas and their associated recurrences. A tissue microarray was constructed to evaluate the CXCL12 immunostained tumor tissue. CXCL12 expression was evaluated and statistically analyzed to correlate clinicopathologic data, overall survival, and recurrence-free survival.

RESULTS

A high proportion of CXCL12 + positive immune cells in primary ovarian serous carcinoma correlated significantly with chemosensitivity (p = 0.005), overall survival (p = 0.021), and longer recurrence-free survival (p = 0.038). In recurrent disease, high expression of CXCL12 was also correlated with better overall survival (p = 0.040). Univariate and multivariate analysis revealed that high CXCL12 + tumor-infiltrating immune cells (TICs) (HR 0.99, p = 0.042, HR 0.99, p = 0.023, respectively) and combined CXCL12 + /CD66b + infiltration (HR 0.15, p = 0.001, HR 0.13, p = 0.001, respectively) are independent favorable predictive markers for recurrence-free survival.

CONCLUSION

A high density of CXCL12 + TICs predicts a good response to chemotherapy, leading to a better overall survival and a longer recurrence-free interval. Moreover, with concomitant high CXCL12/CD66b TIC density, it is an independent favorable predictor of recurrence-free survival in patients with ovarian carcinoma.

Critical Evaluation of Transcripts and Long Noncoding RNA Expression Levels in Prostate Cancer Following Radical Prostatectomy

INTRODUCTION

The clinical course of prostate cancer (PCa) is highly variable, ranging from indolent behavior to rapid metastatic progression. The Gleason score is widely accepted as the primary histologic assessment tool with significant prognostic value. However, additional biomarkers are required to better stratify patients, particularly those at intermediate risk.

METHODS

In this study, we analyzed the expression of 86 cancer hallmark genes in 171 patients with PCa who underwent radical prostatectomy and focused on the outcome of the 137 patients with postoperative R0-PSA0 status.

RESULTS

Low expression of the IGF1 and SRD52A, and high expression of TIMP2, PLAUR, S100A2, and CANX genes were associated with biochemical recurrence (BR), defined as an increase of prostate-specific antigen above 0.2 ng/mL. Furthermore, the analysis of the expression of 462 noncoding RNAs (ncRNA) in a sub-cohort of 39 patients with Gleason score 7 tumors revealed that high levels of expression of the ncRNAs LINC00624, LINC00593, LINC00482, and cd27-AS1 were significantly associated with BR. Our findings provide further evidence for tumor-promoting roles of ncRNAs in PCa patients at intermediate risk. The strong correlation between expression of LINC00624 and KRT8 gene, encoding a well-known cell surface protein present in PCa, further supports a potential contribution of this ncRNA to PCa progression.

CONCLUSION

While larger and further studies are needed to define the role of these genes/ncRNA in PCa, our findings pave the way toward the identification of a subgroup of patients at intermediate risk who may benefit from adjuvant treatments and new therapeutic agents.

Direct CD32 T-cell cytotoxicity: implications for breast cancer prognosis and treatment

The FcγRII (CD32) ligands are IgFc fragments and pentraxins. The existence of additional ligands is unknown. We engineered T cells with human chimeric receptors resulting from the fusion between CD32 extracellular portion and transmembrane CD8α linked to CD28/ζ chain intracellular moiety (CD32-CR). Transduced T cells recognized three breast cancer (BC) and one colon cancer cell line among 15 tested in the absence of targeting antibodies. Sensitive BC cell conjugation with CD32-CR T cells induced CD32 polarization and down-regulation, CD107a release, mutual elimination, and proinflammatory cytokine production unaffected by human IgGs but enhanced by cetuximab. CD32-CR T cells protected immunodeficient mice from subcutaneous growth of MDA-MB-468 BC cells. RNAseq analysis identified a 42 gene fingerprint predicting BC cell sensitivity and favorable outcomes in advanced BC. ICAM1 was a major regulator of CD32-CR T cell-mediated cytotoxicity. CD32-CR T cells may help identify cell surface CD32 ligand(s) and novel prognostically relevant transcriptomic signatures and develop innovative BC treatments.

Identification of TPM2 and CNN1 as Novel Prognostic Markers in Functionally Characterized Human Colon Cancer-Associated Stromal Cells

Simple Summary

Non-transformed cells of tumor microenvironment also impact on cancer outgrowth and progression. In colon cancer, a leading cause of cancer-related death worldwide, a high abundance of a heterogeneous cell population generally referred to as cancer-associated fibroblasts (CAFs) or tumor-associated stromal cells (TASCs) is associated with poor prognosis. The identification of TASC-specific markers could help to select patients for additional treatments and may provide novel targets for innovative therapies. Some markers have been proposed, but their prognostic significance is modest. We successfully expanded TASCs from human colon cancers and demonstrated their capacity to promote tumor growth and metastatic spread in vitro and in in vivo models. By comparing TASC whole protein expression, the so-called “proteome”, with that of stromal cells derived from matched healthy colon tissues, we identified two novel markers highly significantly associated with severe prognosis. Our results might help to identify patients at risk and might suggest new treatment options.

Abstract

Stromal infiltration is associated with poor prognosis in human colon cancers. However, the high heterogeneity of human tumor-associated stromal cells (TASCs) hampers a clear identification of specific markers of prognostic relevance. To address these issues, we established short-term cultures of TASCs and matched healthy mucosa-associated stromal cells (MASCs) from human primary colon cancers and, upon characterization of their phenotypic and functional profiles in vitro and in vivo, we identified differentially expressed markers by proteomic analysis and evaluated their prognostic significance. TASCs were characterized by higher proliferation and differentiation potential, and enhanced expression of mesenchymal stem cell markers, as compared to MASCs. TASC triggered epithelial–mesenchymal transition (EMT) in tumor cells in vitro and promoted their metastatic spread in vivo, as assessed in an orthotopic mouse model. Proteomic analysis of matched TASCs and MASCs identified a panel of markers preferentially expressed in TASCs. The expression of genes encoding two of them, calponin 1 (CNN1) and tropomyosin beta chain isoform 2 (TPM2), was significantly associated with poor outcome in independent databases and outperformed the prognostic significance of currently proposed TASC markers. The newly identified markers may improve prognostication of primary colon cancers and identification of patients at risk.

Nestin and CD34 expression in colorectal cancer predicts improved overall survival

BACKGROUND

Nestin, a class VI intermediate filament protein of the cytoskeleton, and CD34, a transmembrane phosphoglycoprotein, are markers of progenitor cells. This study aimed to evaluate their expression and clinical significance in colorectal cancer.

METHODS

A clinically annotated tissue microarray, including 599 patients with colorectal cancer, was analyzed by immunohistochemistry. Furthermore, nestin and CD34 correlations with HIF-1a and a panel of cytokines and chemokines were assessed using quantitative reverse transcription PCR and The Cancer Genome Atlas dataset.

RESULTS

Expression of nestin and CD34 was observed only in the tumor stroma. Patients displaying high expression of nestin and CD34 demonstrated higher rates of T1 and T2 tumors (p = .020), lower vascular invasion (p < .001) and improved 5-year overall survival (65%; 95% CI = 55-73 vs 45%; 95% CI = 37-53) after adjusting for clinicopathological characteristics (HR: 0.67; 95% CI = 0.46-0.96). A moderate to strong correlation (r = 0.37-0.78, p < .03) of nestin and CD34 was demonstrated for the following markers; HIF-1α, CD4, CD8, FOXP3, IRF1, GATA3, CCL2, CCL3, CXCL12 and CCL21.

CONCLUSIONS

Combined expression of nestin and CD34 expression is associated with better overall survival possibly by modulating a favorable immune response.

Prognostic significance of CD8+ T-cells density in stage III colorectal cancer depends on SDF-1 expression

Since colorectal cancer (CRC) remains one of the most common malignancies, a tremendous amount of studies keep taking place in this field. Over the past 25 years, a notable part of the scientific community has focused on the association between the immune system and colorectal cancer. A variety of studies have shown that high densities of infiltrating CD8+ T-cells are associated with improved disease-free and overall survival in CRC. Stromal cell-derived factor-1 (SDF-1) is a protein that regulates leukocyte trafficking and is variably expressed in several healthy and malignant tissues. There is strong evidence that SDF-1 has a negative prognostic impact on a variety of solid tumors. However, the existing data do not provide sufficient evidence that the expression of SDF-1 has an influence on CRC. Knowing nowadays, that the microenvironment plays a crucial role in the development of cancer, we hypothesized that the expression of SDF-1 in CRC could influence the prognostic significance of CD8+ T-cells, as an indicator of the essential role of the immune microenvironment in cancer development. Therefore, we explored the combined prognostic significance of CD8+ T-cell density and SDF-1 expression in a large CRC collective. We analyzed a tissue microarray of 613 patient specimens of primary CRCs by immunohistochemistry (IHC) for the CD8 + T-cells density and the expression of SDF-1 by tumor cells and tumor-infiltrating immune cells. Besides, we analyzed the expression of SDF-1 at the RNA level in The Cancer Genome Atlas cohort. We found that the combined high CD8+ T-cell infiltration and expression of SDF-1 shows a favorable 5-year overall survival rate (66%; 95% CI 48-79%) compared to tumors showing a high expression of CD8+ T-cell only (55%; 95% CI 45-64%; p = 0.0004). After stratifying the patients in nodal negative and positive groups, we found that the prognostic significance of CD8+ T-cell density in nodal positive colorectal cancer depends on SDF-1 expression. Univariate and multivariate Hazard Cox regression survival analysis considering the combination of both markers revealed that the combined high expression of SDF-1 and CD8+ T-cell density was an independent, favorable, prognostic marker for overall survival (HR = 0.34, 95% CI 0.17-0.66; p = 0.002 and HR = 0.45, 95% CI 0.23-0.89; p = 0.021, respectively). In our cohort there was a very weak correlation between SDF-1 and CD8+ T-cells (rs = 0.13, p = 0.002) and in the trascriptomic expression of these two immune markers display a weak correlation (rs = 0.28, p < 0.001) which was significantly more pronounced in stage III cancers (rs = 0.40, p < 0.001). The combination of high CD8+ T-cell density and expression of SDF-1 represents an independent, favorable, prognostic condition in CRC, mostly in patients with stage III disease.

Fibrosis and cancer: shared features and mechanisms suggest common targeted therapeutic approaches

Epidemiological studies support a strong link between organ fibrosis and epithelial cancers. Moreover, clinical and experimental investigations consistently indicate that these diseases intertwine and share strikingly overlapping features. As a deregulated response to injury occurring in all body tissues, fibrosis is characterized by activation of fibroblasts and immune cells, contributing to progressive deposition of extracellular matrix (ECM) and inflammation. Cancers are driven by genetic alterations resulting in dysregulated cell survival, proliferation and dissemination. However, non-cancerous components of tumour tissues including fibroblasts, inflammatory cells and ECM play key roles in oncogenesis and cancer progression by providing a pro-mutagenic environment where cancer cells can develop, favouring their survival, expansion and invasiveness. Additional commonalities of fibrosis and cancer are also represented by overproduction of growth factors, like transforming growth factor β, epithelial-to-mesenchymal transition, high oxidative stress, Hippo pathway dysfunctions and enhanced cellular senescence. Here, we review advances in the analysis of cellular and molecular mechanisms involved in the pathogenesis of both organ fibrosis and cancer, with particular reference to chronic kidney diseases and renal cell cancers. Most importantly, improved understanding of common features is contributing to the development of innovative treatment strategies targeting shared mechanisms.

Tumor Infiltration by OX40+ Cells Enhances the Prognostic Significance of CD16+ Cell Infiltration in Colorectal Cancer

Objectives:

Analysis of tumor immune infiltration has been suggested to outperform tumor, node, metastasis staging in predicting clinical course of colorectal cancer (CRC). Infiltration by cells expressing OX40, a member of the tumor necrosis factor receptor family, or CD16, expressed by natural killer cells, monocytes, and dendritic cells, has been associated with favorable prognosis in patients with CRC. We hypothesized that assessment of CRC infiltration by both OX40+ and CD16+ cells might result in enhanced prognostic significance.

Methods:

Colorectal cancer infiltration by OX40 and CD16 expressing cells was investigated in 441 primary CRCs using tissue microarrays and specific antibodies, by immunohistochemistry. Patients’ survival was evaluated by Kaplan-Meier and log-rank tests. Multivariate Cox regression analysis, hazard ratios, and 95% confidence intervals were also used to evaluate prognostic significance of OX40+ and CD16+ cell infiltration.

Results:

Colorectal cancer infiltration by OX40+ and CD16+ cells was subclassified into 4 groups with high or low infiltration levels in all possible combinations. High levels of infiltration by both OX40+ and CD16+ cells were associated with lower pT stage, absence of peritumoral lymphocytic (PTL) inflammation, and a positive prognostic impact. Patients bearing tumors with high infiltration by CD16+ and OX40+ cells were also characterized by significantly longer overall survival, as compared with the other groups. These results were confirmed by analyzing an independent validation cohort.

Conclusions:

Combined infiltration by OX40+ and CD16+ immune cells is an independent favorable prognostic marker in CRC. The prognostic value of CD16+ immune cell infiltration is significantly improved by the combined analysis with OX40+ cell infiltration.

CD16-158-valine chimeric receptor T cells overcome the resistance of KRAS-mutated colorectal carcinoma cells to cetuximab

KRAS mutations hinder therapeutic efficacy of epidermal growth factor receptor (EGFR)-specific monoclonal antibodies cetuximab and panitumumab-based immunotherapy of EGFR+ cancers. Although cetuximab inhibits KRAS-mutated cancer cell growth in vitro by natural killer (NK) cell-mediated antibody-dependent cellular cytotoxicity (ADCC), KRAS-mutated colorectal carcinoma (CRC) cells escape NK cell immunosurveillance in vivo. To overcome this limitation, we used cetuximab and panitumumab to redirect Fcγ chimeric receptor (CR) T cells against KRAS-mutated HCT116 colorectal cancer (CRC) cells. We compared four polymorphic Fcγ-CR constructs including CD16158F -CR, CD16158V -CR, CD32131H -CR, and CD32131R -CR transduced into T cells by retroviral vectors. Percentages of transduced T cells expressing CD32131H -CR (83.5 ± 9.5) and CD32131R -CR (77.7 ± 13.2) were significantly higher than those expressing with CD16158F -CR (30.3 ± 10.2) and CD16158V -CR (51.7 ± 13.7) (p < 0.003). CD32131R -CR T cells specifically bound soluble cetuximab and panitumumab. However, only CD16158V -CR T cells released high levels of interferon gamma (IFNγ = 1,145.5 pg/ml ±16.5 pg/ml, p < 0.001) and tumor necrosis factor alpha (TNFα = 614 pg/ml ± 21 pg/ml, p < 0.001) upon incubation with cetuximab-opsonized HCT116 cells. Moreover, only CD16158V -CR T cells combined with cetuximab killed HCT116 cells and A549 KRAS-mutated cells in vitro. CD16158V -CR T cells also effectively controlled subcutaneous growth of HCT116 cells in CB17-SCID mice in vivo. Thus, CD16158V -CR T cells combined with cetuximab represent useful reagents to develop innovative EGFR+KRAS-mutated CRC immunotherapies.

Low Expression of Programmed Death 1 (PD-1), PD-1 Ligand 1 (PD-L1), and Low CD8+ T Lymphocyte Infiltration Identify a Subgroup of Patients With Gastric and Esophageal Adenocarcinoma With Severe Prognosis

Prognosis of gastric and esophageal cancer is poor and treatment improvements are needed. Programmed cell death 1 receptor (PD-1) interaction with its ligand PD-L1 in tumor micro-environment promotes immune tolerance and blocking monoclonal antibodies have entered clinical practice. However, clinical significance of PD-1 and PD-L1 expression in gastric and esophageal adenocarcinomas, particularly in non-Asian patients, is still unclear. Three tissue microarrays including 190 clinically annotated esophageal (n = 31) and gastric (n = 159) adenocarcinomas and 58 paired mucosa specimens, were stained with PD-1, PD-L1, and CD8-specific reagents in indirect immunohistochemistry assays. PD-L1 expression was detectable in 23.2% of cancer specimens. High PD-1 expression was detectable in 37.3% of cases and high CD8+ infiltration in 76%. PD-L1 and high PD1 expression significantly correlated with each other (r_s = 0.404, P < 0.0001) and both significantly correlated with CD8+ infiltration (r_s = 0.435, P = 0.0003, and r_s = 0.444; P = 0.0004, respectively). CD8+ lymphocyte infiltration correlated with improved survival in univariate (P = 0.009), but not multivariate analysis. Most interestingly, multivariate analysis and Kaplan-Meier curves indicate that combined low PD-1/PD-L1 expression and low CD8+ lymphocyte infiltration significantly correlate with poor prognosis. Our data document the clinical significance of a microenvironmental signature including PD-1/PD-L1 expression and CD8+ lymphocyte infiltration in gastric and esophageal adenocarcinomas and contribute to identify a patients' subset requiring more aggressive peri-operative treatments.

Maintenance of Primary Human Colorectal Cancer Microenvironment Using a Perfusion Bioreactor-Based 3D Culture System

Colorectal cancer (CRC) is a leading cause of cancer-related death. Conventional chemotherapeutic regimens have limited success rates, and a major challenge for the development of novel therapies is the lack of adequate in vitro models. Nonmalignant mesenchymal and immune cells of the tumor microenvironment (TME) are known to critically affect CRC progression and drug responsiveness. However, tumor drug sensitivity is still evaluated on systems, such as cell monolayers, spheroids, or tumor xenografts, which typically neglect the original TME. Here, it is investigated whether a bioreactor-based 3D culture system can preserve the main TME cellular components in primary CRC samples. Freshly excised CRC fragments are inserted between two collagen scaffolds in a "sandwich-like" format and cultured under static or perfused conditions up to 3 d. Perfused cultures maintain tumor tissue architecture and densities of proliferating tumor cells to significantly higher extents than static cultures. Stromal and immune cells are also preserved and fully viable, as indicated by their responsiveness to microenvironmental stimuli. Importantly, perfusion-based cultures prove suitable for testing the sensitivity of primary tumor cells to chemotherapies currently in use for CRC. Perfusion-based culture of primary CRC specimens recapitulates TME key features and may allow assessment of tumor drug response in a patient-specific context.

Assessing Autophagy During Retinoid Treatment of Breast Cancer Cells

Retinoids are derived from vitamin A through a multi-step process. Within a target cell, retinoids regulate gene expression by activating the retinoid acid receptors (RAR) and retinoid x receptors (RXR), which are ligand-dependent transcription factors. Besides its therapeutic use in dermatological disorders, all-trans retinoic acid (ATRA) is successfully utilized to treat acute promyelocytic leukemia (APL) patients. The use of ATRA in APL patients is the first example of clinically useful differentiation therapy. Therapeutic strategies aiming at cancer cell differentiation have great potential for solid tumors, including breast cancer. The few clinical studies conducted with ATRA in breast cancer are rather disappointing. However, these studies did not take into account the heterogeneity of the disease and were conducted on unselected cohorts of patients.We recently showed that ATRA treatment of breast cancer cells induces autophagy, a highly conserved process aiming at degrading and recycling superfluous or harmful cellular components. In addition, autophagy inhibition significantly increases the therapeutic activity of ATRA. This finding is of fundamental importance, since autophagy has a dual role in cancer. Whereas autophagy may be a protective mechanism during the initial phases of cancer development, it may support cancer cell survival in already established tumors. Furthermore, autophagy can lower or enhance therapeutic efficiency, depending on the tumor type and the anticancer agent considered. Therefore, it is important to investigate the role of autophagy in the context of specific tumors and therapeutic approaches. Accurate autophagy studies are challenging given the dynamic nature of the process and the difficulty of measuring the rate of autophagosome degradation (autophagic flux). In this chapter, we provide protocols for a careful assessment of the autophagic flux in ATRA treated 2D and 3D breast cancer cultures.

Anticancer activity of paclitaxel-loaded keratin nanoparticles in two-dimensional and perfused three-dimensional breast cancer models

PURPOSE

Taxanes are highly effective cytotoxic drugs for progressing breast cancer treatment. However, their poor solubility and high toxicity urge the development of innovative formulations of potential clinical relevance.

MATERIALS AND METHODS

By using a simple and straightforward aggregation method, we have generated paclitaxel (PTX) loaded in keratin nanoparticles (KER-NPs-PTX). Their activities were tested against human breast cancer MCF-7 and MDA MB 231 cell lines in conventional two-dimensional (2D) cultures and in a dynamic three-dimensional (3D) model with perfused bioreactor (p3D). Moreover, KER-NPs-PTX activity was compared to free PTX and to PTX loaded in albumin nanoparticles (HSA-NPs-PTX). Cell viability, induction of apoptosis, and gene expression analysis were used as readouts.

RESULTS

In 2D cultures, KER-NPs-PTX was able to inhibit tumor cell viability and to induce apoptosis similarly to PTX and HSA-NPs-PTX. In the p3D model, a lower sensitivity of tumor cells to treatments was observed. Importantly, only KER-NPs-PTX was able to induce a statistically significant increase in apoptotic cell percentages following 24 h treatment for MCF-7 (16.7±4.0 early and 11.3±4.9 late apoptotic cells) and 48 h treatment for MDA MB 231 (21.3±11.2 early and 10.5±1.8 late apoptotic cells) cells. These effects were supported, at least for MCF-7 cells, by significant increases in the expression of proapoptotic BAX gene (5.8±0.5) 24 h after treatment and of cleaved caspase 3 (CC3) protein.

CONCLUSION

KER-NPs-PTX, generated by a simple procedure, is characterized by high water solubility and enhanced PTX-loading ability, as compared to HSA-NPs-PTX. Most importantly, it appears to be able to exert effective anticancer activities on breast cancer cells cultured in 2D or in p3D models.

Abstract 4097: Maintenance of primary human colorectal cancer microenvironment using a perfusion bioreactor-based 3D culture system

Colorectal cancer (CRC) is a leading cause of cancer-related death, often diagnosed at advanced stages. Conventional chemotherapeutic regimens have limited success rates, and a major challenge is represented by the lack of adequate in vitro models predicting patient responsiveness to defined treatments, possibly guiding therapeutic decisions. Non-malignant cells, including mesenchymal and immune cells, critically affect development, progression and drug responsiveness of human CRC. However, tumor drug responses are still evaluated on culture systems, such as 2D tumor cell monocultures or on tumor xenografts, which do not preserve all cellular components of in vivo tumor microenvironment.In this work, we have investigated the suitability of a perfusion-based bioreactor for 3D culture of primary CRC samples. Freshly excised CRC specimens were cut into fragments, inserted between two collagen type I sponges in a “sandwich-like” format and cultured for three days in a perfused-based system or under static conditions.We show that cultures under perfusion result in significantly higher maintenance of tissue integrity as compared to static cultures, with preservation of whole tumor microenvironment components, including cancer cells, mesenchymal stromal cells and a fraction of immune cells. Tumor tissues cultured under perfusion displayed an almost intact architecture with viable and proliferating tumor cells. Stromal cells were also maintained in proportions similar to those of original tumors and were fully viable, as indicated by their responsiveness to microenvironmental stimuli, such as IL-17. In addition, immune cells were also partially preserved, and were capable to release effector cytokines upon activation. Importantly, perfusion-based cultures proved suitable for testing sensitivity of primary tumor cells to chemotherapies currently in use for CRC and revealed heterogeneous responsiveness across different samples.

[C.M. and M.G.M. contributed equally to this work.]

Citation Format: Celeste Manfredonia, Manuele Giuseppe Muraro, Christian Hirt, Valentina Mele, Valeria Governa, Adam Papadimitropoulos, Silvio Daester, Savas D. Soysal, Raoul A. Droeser, Robert Mechera, Daniel Oertli, Raffaele Rosso, Martin Bolli, Luigi M. Terracciano, Giulio C. Spagnoli, Ivan Martin, Giandomenica Iezzi. Maintenance of primary human colorectal cancer microenvironment using a perfusion bioreactor-based 3D culture system [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4097.

Abstract 2109: Prognostic and functional significance of interleukin 22 in colorectal cancer

T cell infiltration has been recognized to significantly impact clinical outcome in human colorectal cancer (CRC). Interleukin 22 (IL-22), a cytokine secreted by IL-17-producing CD4+ T cells (Th17) is known to play a crucial role in inflammatory bowel disease and has been shown to have protumorigenic activity in mouse tumor models. However, its role in human CRC is still unclear. In a previous study we could demonstrate the dual role of Th17 in CRC. As consequence we evaluated the prognostic and functional impact of IL-22 producing cells in human CRC in this follow-up study. Upon staining of a tissue microarray (TMA), including 423 CRC cases, IL-22 positive cells were detected both within tumor cells and tumor infiltrating immune cells. Whereas, IL-22 expression by tumor cells did not impact on prognosis, densities of IL-22 positive immune cells were found to be significantly associated with early T stage and MMR-deficient microsatellite stability. Importantly, IL-22 expression by CRC infiltrating immune cells was predictive of improved overall survival independent of known prognostic factors such as T stage, N stage, tumor grade, vascular invasion, tumor border configuration and MMR status. Phenotypic characterization of IL-22 positive cells performed by flow cytometry revealed that they consist mainly of Th17 cells, also producing IL-17. In vitro experiments showed no direct effect of IL-22 on CRC cell proliferation. On-going studies are validating the prognostic effect on a TMA cohort with corresponding transcriptomic data and evaluating potential effects mediated by IL-22 on other cell types of CRC microenvironment.

Citation Format: Eleonora Cremonesi, Nadia Tosti, Francesca Amicarella, Benjamin Weixler, Silvio Däster, Valeria Governa, Giulio C. Spagnoli, Luigi Terracciano, Luigi Tornillo, Serenella Eppenberger-Castori, Giandomenica Iezzi, Raoul Droeser. Prognostic and functional significance of interleukin 22 in colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2109.

Expression of Indoleamine 2,3-Dioxygenase Induced by IFN-γ and TNF-α as Potential Biomarker of Prostate Cancer Progression

Inflammation has been suggested to play an important role in onset and progression of prostate cancer (PCa). Histological analysis of prostatectomy specimens has revealed focal inflammation in early stage lesions of this malignancy. We addressed the role of inflammatory stimuli in the release of PCa-specific, tumor-derived soluble factors (PCa-TDSFs) already reported to be mediators of PCa morbidity, such as indoleamine 2,3-dioxygenase (IDO) and interleukin (IL)-6. Inflammation-driven production and functions of PCa-TDFSs were tested "in vitro" by stimulating established cell lines (CA-HPV-10 and PC3) with IFN-γ or TNF-α. Expression of genes encoding IDO, IL-6, IFN-γ, TNF-α, and their receptors was investigated in tumor tissues of PCa patients undergoing radical prostatectomy, in comparison with benign prostatic hyperplasia (BPH) specimens. IFN-γ and TNF-α-treatment resulted in the induction of IDO and IL-6 gene expression and release in established cell lines, suggesting that the elicitation of PCa-TDSFs by these cytokines might contribute to progression of cancer into an untreatable phenotype. An analysis based on timing of biochemical recurrence revealed the prognostic value of IDO but not IL-6 gene expression in predicting recurrence-free survival in patients (RFS) with PCa. In addition, a urine-based mRNA biomarker study revealed the diagnostic potential of IDO gene expression in urines of men at risk of PCa development.

Induction of hypoxia and necrosis in multicellular tumor spheroids is associated with resistance to chemotherapy treatment

Culture of cancerous cells in standard monolayer conditions poorly mirrors growth in three-dimensional architectures typically observed in a wide majority of cancers of different histological origin. Multicellular tumor spheroid (MCTS) culture models were developed to mimic these features. However, in vivo tumor growth is also characterized by the presence of ischemic and necrotic areas generated by oxygenation gradients and differential access to nutrients. Hypoxia and necrosis play key roles in tumor progression and resistance to treatment. To provide in vitro models recapitulating these events in highly controlled and standardized conditions, we have generated colorectal cancer (CRC) cell spheroids of different sizes and analyzed their gene expression profiles and sensitivity to treatment with 5FU, currently used in therapeutic protocols. Here we identify three MCTS stages, corresponding to defined spheroid sizes, characterized by normoxia, hypoxia, and hypoxia plus necrosis, respectively. Importantly, we show that MCTS including both hypoxic and necrotic areas most closely mimic gene expression profiles of in vivo-developing tumors and display the highest resistance to 5FU. Taken together, our data indicate that MCTS may mimic in vitro generation of ischemic and necrotic areas in highly standardized and controlled conditions, thereby qualifying as relevant models for drug screening purposes.

Phosphorylated CXCR4 expression has a positive prognostic impact in colorectal cancer

BACKGROUND

The CXCL12-CXCR4 chemokine axis plays an important role in cell trafficking as well as in tumor progression. In colorectal cancer (CRC), the chemokine receptor CXCR4 has been shown to be an unfavorable prognostic factor in some studies, however, the role of its activated (phosphorylated) form, pCXCR4, has not yet been evaluated. Here, we aimed to investigate the prognostic value of CXCR4 and pCXCR4 in a large cohort of CRC patients.

PATIENTS AND METHODS

A tissue microarray (TMA) of 684 patient specimens of primary CRCs was analyzed by immunohistochemistry (IHC) for the expression of CXCR4 and pCXCR4 by tumor cells and tumor-infiltrating immune cells (TICs).

RESULTS

The combined high expression of CXCR4 and pCXCR4 showed a favorable 5-year overall survival rate (68%; 95%CI = 59-76%) compared to tumors showing a high expression of CXCR4 only (48%; 95%CI = 41-54%). High expression of pCXCR4 was significantly associated with a favorable prognosis in a test and validation group (p = 0.015 and p = 0.0001). Moreover, we found that CRCs with a high density of pCXCR4+ tumor-infiltrating immune cells (TICs) also showed a favorable prognosis in a test and validation group (p = 0.054 and p = 0.004). Univariate Cox regression analysis for TICs revealed that a high density of pCXCR4+ TICs was a favorable prognostic marker for overall survival (HR = 0.97,95%CI = 0.96-1.00; p = 0.01). In multivariate Cox regression survival analyses a high expression of pCXCR4 in tumor cells lost its association with a better overall survival (HR = 0.99; 95%CI = 0.99-1.00, p = 0.098).

CONCLUSION

Our results show that high densities of CXCR4 and pCXCR4 positive TICs are favorable prognostic factors in CRC.

In Vitro Modeling of Tumor-Immune System Interaction

Immunotherapy has emerged during the past two decades as an innovative and successful form of cancer treatment. However, frequently, mechanisms of actions are still unclear, predictive markers are insufficiently characterized, and preclinical assays for innovative treatments are poorly reliable. In this context, the analysis of tumor/immune system interaction plays key roles, but may be unreliably mirrored by in vivo experimental models and standard bidimensional culture systems. Tridimensional cultures of tumor cells have been developed to bridge the gap between in vitro and in vivo systems. Interestingly, defined aspects of the interaction of cells from adaptive and innate immune systems and tumor cells may also be mirrored by 3D cultures. Here we review in vitro models of cancer/immune cell interaction and we propose that updated technologies might help develop innovative treatments, identify biologicals of potential clinical relevance, and select patients eligible for immunotherapy treatments.

Abstract 4833: Perfusion-based bioreactor culture of primary cancer tissue maintains tumor microenvironment complexity and allow in-vitro testing of immune blockade therapy

In vitro culture of primary cancer tissue is still very limited and the generation of patient derived xenograft determine the loss of human-cancer associated stroma. In this context, the use of 3D in vitro systems based on human tissue may be an innovative system to be exploited for keeping the tumor microenvironment (TME) complexity of the tissue in vitro.

Freshly excised colorectal (CRC) and breast cancer (BrCa) specimens were fragmented and cultured in 3D “sandwich-like format” between porous collagen scaffolds under perfusion flow (U-CUP, Cellec Biotek AG). The maintenance of tumor and immune-infiltrating cells, survival and phenotypic characterization were histologically assessed. In a second step cancer treatment were tested.

U-CUP culture allowed the preservation, viability and expansion of tumor tissue with concomitant stromal and immune cells. Expanding cancer cells were viable after 10 and 21 days (CRC and BrCa, respectively). Administration of anti-ER treatment to Lumina A ER+ BrCa was associated with decreased expansion of cancer tissue into the scaffold after 21 days. The maintenance of immune-infiltrating cells allowed testing of immune blockade therapy. Administration of anti-PDL1 antibody, alone or in combination with anti-CTLA4, to the culture medium was associated with increased expression of markers of immune-activation (i.e. IFNγ) and decreased expression of immunosuppressive cytokine IL10.

Preserving malignant, interstitial and immunocompetent cells comprised in surgically excised tumor specimens might allow a direct evaluation of the effects of various treatments on the complex TME. This engineered in vitro model could allow animal-free testing and it could be extended as a platform allowing the testing of innovative approaches for the treatment of human malignancies. Our findings shed the light on a promising system for selecting personalized treatment based on a patient’s tumor specific microenvironment.

Note: This abstract was not presented at the meeting.

Citation Format: Manuele Giuseppe Muraro, Simone Muenst, Celeste Manfredonia, Valentina Mele, Silvio Daester, Alexandar Tzankov, Luigi Terracciano, Walter Weber, Giulio C. Spagnoli, Giandomenica Iezzi, Ivan Martin, Savas D. Soysal. Perfusion-based bioreactor culture of primary cancer tissue maintains tumor microenvironment complexity and allow in-vitro testing of immune blockade therapy [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 4833. doi:10.1158/1538-7445.AM2017-4833

Ex-vivo assessment of drug response on breast cancer primary tissue with preserved microenvironments

Interaction between cancerous, non-transformed cells, and non-cellular components within the tumor microenvironment plays a key role in response to treatment. However, short-term culture or xenotransplantation of cancer specimens in immunodeficient animals results in dramatic modifications of the tumor microenvironment, thus preventing reliable assessment of compounds or biologicals of potential therapeutic relevance. We used a perfusion-based bioreactor developed for tissue engineering purposes to successfully maintain the tumor microenvironment of freshly excised breast cancer tissue obtained from 27 breast cancer patients and used this platform to test the therapeutic effect of antiestrogens as well as checkpoint-inhibitors on the cancer cells. Viability and functions of tumor and immune cells could be maintained for over 2 weeks in perfused bioreactors. Next generation sequencing authenticated cultured tissue specimens as closely matching the original clinical samples. Anti-estrogen treatment of cultured estrogen receptor positive breast cancer tissue as well as administration of pertuzumab to a Her2 positive breast cancer both had an anti-proliferative effect. Treatment with anti-programmed-death-Ligand (PD-L)-1 and anti-cytotoxic T lymphocyte-associated protein (CTLA)-4 antibodies lead to immune activation, evidenced by increased lymphocyte proliferation, increased expression of IFNγ, and decreased expression of IL10, accompanied by a massive cancer cell death in ex vivo triple negative breast cancer specimens. In the era of personalized medicine, the ex vivo culture of breast cancer tissue represents a promising approach for the pre-clinical evaluation of conventional and immune-mediated treatments and provides a platform for testing of innovative treatments.

mTORC1/autophagy-regulated MerTK in mutant BRAFV600 melanoma with acquired resistance to BRAF inhibition

BRAF inhibitors (BRAFi) and the combination therapy of BRAF and MEK inhibitors (MEKi) were recently approved for therapy of metastatic melanomas harbouring the oncogenic BRAFV600 mutation. Although these therapies have shown pronounced therapeutic efficacy, the limited durability of the response indicates an acquired drug resistance that still remains mechanistically poorly understood at the molecular level. We conducted transcriptome gene profiling in BRAFi-treated melanoma cells and identified that Mer tyrosine kinase (MerTK) is specifically upregulated. MerTK overexpression was demonstrated not only in melanomas resistant to BRAFi monotherapy (5 out of 10 samples from melanoma patients) but also in melanoma resistant to BRAFi+MEKi (1 out of 3), although MEKi alone does not affect MerTK. Mechanistically, BRAFi-induced activation of Zeb2 stimulates MerTK in BRAFV600 melanoma through mTORC1-triggered activation of autophagy. Co-targeting MerTK and BRAFV600 significantly reduced tumour burden in xenografted mice, which was pheno-copied by co-inhibition of autophagy and mutant BRAFV600.

Expression of Indoleamine 2,3-Dioxygenase Gene Is a Feature of Poorly Differentiated Non-muscle-invasive Urothelial Cell Bladder Carcinomas

AIM

To evaluate indoleamine 2,3-dioxygenase (IDO) gene expression in non-muscle-invasive urothelial cell bladder carcinoma (NMIBC).

PATIENTS AND METHODS

Seventy-four patients undergoing surgical treatment for NMIBC were enrolled in the study. IDO gene expression was assessed by quantitative real-time polymerase chain reaction (qRT-PCR).

RESULTS

IDO gene expression was detectable significantly more frequently (48/74, 64.86% vs. 5/21, 23.81%, p<0.001) and to significantly higher extents (p=0.01) in cancer tissues than in normal bladder mucosa. IDO gene expression was observed significantly more frequently in large (p=0.02), high-grade (p=0.05) and stage T1 (p=0.03) than in small, low-grade and stage Ta tumors. Expression levels were also significantly higher in large, high-grade and stage T1 tumors (p<0.01, p=0.05 and p=0.03, respectively). A direct positive correlation between IDO gene expression in tumor tissues and tumor size (R=0.24, p=0.04), grade (R=0.23, p=0.05) and stage (R=0.25, p=0.03) was detected. Multivariate analysis suggested a trend (p=0.08) towards longer overall survival in patients bearing tumors that did not express IDO gene.

CONCLUSION

These data indicate that IDO gene expression is a feature of aggressive NMIBC, suggesting a potential immunosuppressive role of IDO.

MAGE-A Antigens and Cancer Immunotherapy

MAGE-A antigens are expressed in a variety of cancers of diverse histological origin and germinal cells. Due to their relatively high tumor specificity, they represent attractive targets for active specific and adoptive cancer immunotherapies. Here, we (i) review past and ongoing clinical studies targeting these antigens, (ii) analyze advantages and disadvantages of different therapeutic approaches, and (iii) discuss possible improvements in MAGE-A-specific immunotherapies.

The Interplay Between Neutrophils and CD8+ T Cells Improves Survival in Human Colorectal Cancer

Purpose: Tumor infiltration by different T lymphocyte subsets is known to be associated with favorable prognosis in colorectal cancer. Still debated is the role of innate immune system. We investigated clinical relevance, phenotypes, and functional features of colorectal cancer-infiltrating CD66b⁺ neutrophils and their crosstalk with CD8⁺ T cells.Experimental Design: CD66b⁺ and CD8⁺ cell infiltration was analyzed by IHC on a tissue microarray including >650 evaluable colorectal cancer samples. Phenotypic profiles of tissue-infiltrating and peripheral blood CD66b⁺ cells were evaluated by flow cytometry. CD66b⁺/CD8⁺ cells crosstalk was investigated by in vitro experiments.Results: CD66b⁺ cell infiltration in colorectal cancer is significantly associated with increased survival. Interestingly, neutrophils frequently colocalize with CD8⁺ T cells in colorectal cancer. Functional studies indicate that although neutrophils are devoid of direct antitumor potential, coculture with peripheral blood or tumor-associated neutrophils (TAN) enhances CD8⁺ T-cell activation, proliferation, and cytokine release induced by suboptimal concentrations of anti-CD3 mAb. Moreover, under optimal activation conditions, CD8⁺ cell stimulation in the presence of CD66b⁺ cells results in increasing numbers of cells expressing CD45RO/CD62L "central memory" phenotype. Importantly, combined tumor infiltration by CD66b⁺ and CD8⁺ T lymphocytes is associated with significantly better prognosis, as compared with CD8⁺ T-cell infiltration alone.Conclusions: Neutrophils enhance the responsiveness of CD8⁺ T cells to T-cell receptor triggering. Accordingly, infiltration by neutrophils enhances the prognostic significance of colorectal cancer infiltration by CD8⁺ T cells, suggesting that they might effectively promote antitumor immunity. Clin Cancer Res; 23(14); 3847-58. ©2017 AACR.

Abstract 615: Scaffold-based perfusion bioreactor system for in vitro maintenance of primary breast cancer tissue microenvironment suitable for personalized medicine

INTRODUCTION Two-dimensional (2D) in vitro culture systems and in vivo animal models are the primary tools used to test cancer cell responses to drugs but they are not suited for the development of immune-mediate therapies. Here we present an innovative method for in vitro culture primary breast cancer (BrCa) tissues in porous 3D scaffolds by using a perfusion-based bioreactor system (U-CUP).

MATERIALS & METHODS Freshly excised breast cancer specimens were fragmented and cultured in a 3D “sandwich-like format” between collagen porous scaffolds under perfusion flow. DMEM/F12, supplemented with 10% autologous human serum, was used as a culture medium. Malignant and non-malignant cells survival, expansion into the scaffold and the ability to recapitulate features of the original BrCa specimens were histologically assessed. For estrogen receptor (ER) positive tissues we tested the response to hormonal therapy by adding the anti-ER drug Fulvestrant. Furthermore, the maintenance of immune-infiltrating cells allowed testing immune blockade therapy in vitro using anti PD-L1 on PD-L1 positive samples. Response to treatment was evaluated by histology and qRT-PCR for markers of immune-response.

RESULTS By culturing BrCa using the U-CUP we were able to preserve viability and to promote the expansion of breast cancer cells from surgical specimens together with accompanying stromal and immune cells into the porous scaffold. Expanding cancer cells were viable after 21 days and recapitulating the initial histology with formation of glands. Administration of anti-ER treatment was associated with decreased expansion of cancer tissue into the scaffold after 21 days. After 7 days of anti PD-L1 antibody treatment we observed a reduced number of tumor cells due to the activation of infiltrating lymphocytes, as shown by increased expression of IFNg and decreased expression of IL10.

CONCLUSIONS The scaffold-based perfusion bioreactor represents a successful organotypic tumor model allowing in vitro long-term culture of breast cancer specimens. Our findings shed the light on a promising system for selecting personalized treatment based on a patient's tumor specific microenvironment.

Citation Format: Manuele Giuseppe Muraro, Simone Muenst, Valentina Mele, Luca Quagliata, Alexandar Tzankov, Walter P. Weber, Giulio C. Spagnoli, Savas D. Soysal. Scaffold-based perfusion bioreactor system for in vitro maintenance of primary breast cancer tissue microenvironment suitable for personalized medicine. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 615.

Abstract 4031: Different expression of programmed death 1 (PD1) and its ligand (PD-L1) in esophageal and gastric cancer

Background: Prognosis of gastric and esophageal cancer remains poor. Improvements in gastric and esophageal cancer treatments are urgently needed. Programmed cell death 1 receptor (PD1) and its ligand 1 (PD-L1) are known to interact with T cells promoting epithelial cancer tolerance. Several therapeutic monoclonal antibodies blocking this interaction are reaching the clinical praxis. Therefore it is relevant to investigate the role of these biomarkers in different types of malignancy.

Methods: Four different copies of tissue microarrays (TMA), each including healthy mucosa (n = 74) and a total of 241 clinically annotated malignancies of the esophagus (n = 80) and stomach (n = 161) were constructed and stained with PD1, PD-L1, and CD8 specific reagents.

Results: Interestingly, only two cancer samples out of the 241 specimens investigated weakly expressed PD-L1. None of the normal mucosa epithelial cells expressed PD-L1. Stromal PD1 expression correlated with infiltration by CD8+ lymphocytes (rho = 0.4; P&lt;0.0001). Elevated intraepithelial presence of CD8+ and/or PD1+ cells in gastric cancer was significantly correlated with longer patients’ survival. No correlation could be found in esophageal cancer.

Conclusion: In contrast to other epithelial cancers, PD-L1 expression was virtually absent in the investigated malignancies of the esophagus and stomach. PD1 expression in the stroma surrounding such malignancies correlated with intraepithelial presence of T-cells CD8+ expression, and with better prognosis in gastric cancer patients.

Citation Format: Silvio Däster, Serenella Eppenberger-Castori, Raoul A. Droeser, Hannah M. Schaefer, Giulio C. Spagnoli, Luigi Terracciano, Luigi Tornillo, Urs von Holzen. Different expression of programmed death 1 (PD1) and its ligand (PD-L1) in esophageal and gastric cancer. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4031.

Abstract 1582: Tumor-associated stromal cells increase malignancy of human colorectal cancers triggering EMT induction

In the last decades it has been demonstrated that the stroma surrounding tumor not only provides mechanical support, but profoundly influences the outcome of the primary tumor and its possible relapse, impacting on proliferation, metastatic progression and resistance to therapies. Major components of the stroma in most types of human carcinomas are the Tumor-Associated Stromal Cells (TASC). Different sources have been proposed for this population, ranging from the resident fibroblasts to bone marrow-derived mesenchymal stromal cells (BM-MSC) recruited to the trans-differentiated epithelial and endothelial cells, but the scenario is still unclear. Moreover, TASC have an intrinsic heterogeneity, combined also with the presence of multiple subpopulations, and they share several markers with other cell subsets of the stroma, thus making the identification of this population, based on the expression of specific markers, an arduous task.

In this intricate context, we aim to address phenotypic and functional characterization of TASC isolated from colorectal cancer specimens, and to analyze TASC-mediated effects on CRC development and progression in vivo.

TASC were characterized for phenotype and differentiation capacity. Human CRC cells were cultured in the presence or absence of TASC for five days. After co-culture tumor cells were sorted by flow cytometry and evaluated for the expression of EMT-related genes by Real Time PCR and for in vitro invasiveness by chemoinvasion assay. Furthermore, their tumorigenicity and the metastatic potential were assessed upon subcutaneous and intracoecally injection in NOD/SCID mice. Developed tumors, metastatic foci and circulating tumor cells were assessed by histology, flow cytometry and Imaging Flow Cytometry.

Our results indicate that TASC resemble BM-MSC in morphology and phenotype. They also comprise a multipotent subpopulation that is able to differentiate into adipogenic and osteogenic lineage. After co-culture with CRC cells, TASC express membrane-bound TGF-β, through which they are capable to trigger epithelial-to-mesenchymal transition (EMT). Upon subcutaneous injection in NOD/SCID mice, tumor cells co-cultured or admixed with TASC before injection, show a faster growth kinetic and develop larger tumor masses as compared to tumor cells alone. Furthermore developed tumor masses are characterized by a higher vessel density. Notably, upon intracoecal injection TASC presence or conditioning leads to a higher metastatic formation in lungs and livers and an increased number of circulating tumor cells in the peripheral blood, most importantly comprising cells undergoing EMT.

Our data clearly show that the stromal component in the human colorectal cancer microenvironment increases the malignancy of tumor cells, by providing pro-mitogenic factors and by triggering EMT initiation in vitro and in vivo, thus promoting tumorigenicity and metastasis formation in vivo.

Citation Format: Valentina Mele, Valeria Governa, Manuele G. Muraro, Jesus F. Glaus Garzon, Lubor Borsig, Silvio Daester, Raoul Droeser, Daniel Oertli, Markus Zuber, Raffaele Rosso, Giulio C. Spagnoli, Giandomenica Iezzi. Tumor-associated stromal cells increase malignancy of human colorectal cancers triggering EMT induction. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1582.

Abstract P4-04-19: Primary breast cancer culture in a perfusion-based bioreactor suitable for in vitro testing of immune blockade therapy

Introduction: Interaction between cancer cells and immune system critically affects development, progression and treatment of human malignancies. Two-dimensional (2D) in vitro culture systems and in vivo animal models are the primary tools used to test cancer cell response to drugs but they are not suited for the development of immune-mediated therapies. Here we present an innovative method to culture breast cancer tissue in porous 3D scaffolds by using a perfusion-based bioreactor system that allows the maintenance and expansion of tumor microenvironment.

Experimental procedures: Freshly excised breast cancer specimens were fragmented and cultured in a 3D "sandwich-like format" between two layers of porous collagen scaffold under perfusion flow (U-CUP). DMEM/F12, supplemented with 10% autologous human serum, was used as a culture medium. We assessed the ability of tumor and non-malignant cells to survive and expand into the scaffold in perfusion culture, as well as their capacity to recapitulate features of the original breast cancer tissue. The maintenance of immune-infiltrating cells allowed testing of immune blockade therapy in vitro using anti-PD-L1 and anti-CTLA4 antibodies alone or in combination.

Results: The U-CUP culture system preserved tissue viability better compared to a static culture and promoted the expansion of breast cancer cells from surgical specimens together with accompanying stromal and immune cells into the porous scaffold. Tumor tissues were viable after 21 days and mostly recapitulating the initial histology with formation of glands. Administration of anti-PDL1 antibody, alone or in combination with anti-CTLA4, to the culture medium was associated with increased expression of markers of immune-activation (i.e. IFNg) and decreased expression of immunosuppressive cytokine IL10.

Conclusions: Our results show that culture of breast cancer tissue in a 3D perfusion-based bioreactor might represent a promising system for the pre-clinical evaluation of immune-mediated therapies. Preserving malignant, interstitial and immunocompetent cells comprised in surgically excised breast cancer samples might allow a direct evaluation of the effects of various treatments on the complex tumor microenvironment. This engineered in vitro model could be extended as a platform allowing the testing of innovative approaches for the treatment of human malignancies, possibly in the direction of personalized medicine.

Citation Format: Muraro MG, Muenst S, Mele V, Spagnoli GC, Oertli D, Weber WP, Soysal SD. Primary breast cancer culture in a perfusion-based bioreactor suitable for in vitro testing of immune blockade therapy. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P4-04-19.

CD40 ligand-expressing recombinant vaccinia virus promotes the generation of CD8(+) central memory T cells

Central memory CD8(+) T cells (TCM ) play key roles in the protective immunity against infectious agents, cancer immunotherapy, and adoptive treatments of malignant and viral diseases. CD8(+) TCM cells are characterized by specific phenotypes, homing, and proliferative capacities. However, CD8(+) TCM -cell generation is challenging, and usually requires CD4(+) CD40L(+) T-cell "help" during the priming of naïve CD8(+) T cells. We have generated a replication incompetent CD40 ligand-expressing recombinant vaccinia virus (rVV40L) to promote the differentiation of human naïve CD8(+) T cells into TCM specific for viral and tumor-associated antigens. Soluble CD40 ligand recombinant protein (sCD40L), and vaccinia virus wild-type (VV WT), alone or in combination, were used as controls. Here, we show that, in the absence of CD4(+) T cells, a single "in vitro" stimulation of naïve CD8(+) T cells by rVV40L-infected nonprofessional CD14(+) antigen presenting cells promotes the rapid generation of viral or tumor associated antigen-specific CD8(+) T cells displaying TCM phenotypic and functional properties. These observations demonstrate the high ability of rVV40L to fine tune CD8(+) mediated immune responses, and strongly support the use of similar reagents for clinical immunization and adoptive immunotherapy purposes.

Absence of myeloperoxidase and CD8 positive cells in colorectal cancer infiltrates identifies patients with severe prognosis

Colorectal cancer (CRC) infiltration by cells expressing myeloperoxidase (MPO) or CD8 positive T lymphocytes has been shown to be independently associated with favorable prognosis. We explored the relationship occurring between CD8+ and MPO+ cell CRC infiltration, its impact on clinical-pathological features and its prognostic significance in a tissue microarray (TMA) including 1,162 CRC. We observed that CRC showing high MPO+ cell infiltration are characterized by a prognosis as favorable as that of cancers with high CD8+ T cell infiltration. However, MPO+ and CD8+ CRC infiltrating cells did not synergize in determining a more favorable outcome, as compared with cancers showing MPOhigh/CD8low or MPOlow/CD8high infiltrates. Most importantly, we identified a subgroup of CRC with MPOlow/CD8low tumor infiltration characterized by a particularly severe prognosis. Intriguingly, although MPO+ and CD8+ cells did not co-localize in CRC infiltrates, an increased expression of TIA-1 and granzyme-B was detectable in T cells infiltrating CRC with high MPO+ cell density.

Abstract 2370: Tumor-associated stromal cells increase malignancy of human colorectal cancers triggering the induction of Epithelial-to-mesenchymal transition

During tumor formation, normal tissue microenvironment is transformed in an “altered” niche, composed of non-malignant supporting cells, which influence the homeostasis of cancer cells via paracrine regulators. Tumor-associated stromal cells (TASC) are the prominent stromal elements in most types of human carcinomas including colorectal cancer (CRC). The differentiation of TASC from other cell types, such as resident stromal cells or bone marrow-derived mesenchymal stem cells (BM-MSC) is mainly mediated by factors produced during the crosstalk with malignant cells. TASC produce various extracellular matrix proteins, chemokines, and other tumor-promoting factors which affect vascularization, proliferation, tumor cell invasiveness and survival. Emerging data suggests that they also play a critical role in determining response to therapy. For instance TASC-derived factors may contribute to the development of a protective milieu by influencing cell-cell/cell-matrix interactions, cancer cell survival, and suppression of anti-tumor immune responses. Moreover, physical contact between TASC and malignant cells supports tumor cell survival via activation of anti-apoptotic pathways or inducing epithelial-to-mesenchymal transition (EMT). We previously showed that BM-MSC are capable of triggering EMT in CRC cells, leading to increased tumor cell aggressiveness in vitro and in vivo. However, the role played by the stromal component and the processes induced on CRC cells remain to be fully elucidated. For this purpose we have addressed phenotypic and functional characterization of TASC in vitro and we have analyzed TASC-mediated effects on CRC development and progression in vivo.

TASC were characterized for phenotype and differentiation capacity. Human CRC cells were cultured in the presence or absence of TASC for five days. After co-culture tumor cells were sorted by flow cytometry and evaluated for the expression of EMT-related genes by Real Time PCR and for in vitro invasiveness by chemoinvasion assay. Furthermore, their tumorigenicity was assessed upon injection in NOD/SCID mice and developing tumors were analyzed.

Our results indicate that TASC resemble BM-MSC in morphology and phenotype. They comprise a multipotent subpopulation that is able to differentiate into adipogenic and osteogenic lineage. After co-culture with CRC cells they express membrane-bound TGF-β, through which they are capable to initiate EMT in tumor cells. Moreover CRC cells acquire a more invasive phenotype after co-culture with TASC. Upon subcutaneous injection in NOD/SCID mice, tumor cells co-cultured with TASC show a significantly faster growth kinetic and develop significantly larger tumor masses as compared to tumor cells alone.

Thus our data show that the stromal component of CRC increases the tumor cells malignancy triggering EMT induction.

Citation Format: Valentina Mele, Manuele Giuseppe Muraro, Raoul Droeser, Daniel Oertli, Markus Zuber, Raffaele Rosso, Ivan Martin, Michael Heberer, Giulio C. Spagnoli, Giandomenica Iezzi. Tumor-associated stromal cells increase malignancy of human colorectal cancers triggering the induction of Epithelial-to-mesenchymal transition. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2370. doi:10.1158/1538-7445.AM2015-2370

Abstract 328: Original microenvironment of different cancer types is maintained upon culture of primary tissues in perfused bioreactors

The development of novel three-dimensional (3D) culture systems allowing the survival/expansion of primary tumors in vitro may help to bridge the gap between conventional bi-dimensional (2D) cultures and animal models, poorly predictive of therapeutic responses.

We have investigated the suitability of a previously developed perfused bioreactor system for the in vitro culture of human primary tumor tissues.

Surgical specimens of colorectal cancer (CRC, n = 15), glioblastoma (n = 3), breast cancer (n = 3), sarcoma (n = 2), and melanoma (n = 1) were used. Tumor fragments, obtained upon mechanical mincing and enzymatic digestion, were cultured on collagen scaffolds, in medium supplemented with human serum, under alternate perfusion up to 20 days. Characterization of expanded tissues was performed by histo-morphological analysis, immunofluorescence and gene expression profiling.

CRC tissues were effectively expanded in perfused 3D cultures in 10 out of 15 cases, whereas no expansion was observed under static culture conditions. Gene profiles of expanded tumor tissues suggested a heterogeneous tissue composition, as indicated by the expression of EpCAM, CD90, CD8, CD16 and Foxp3 genes. Phenotypic analysis confirmed that expanded tissues included epithelial and stromal cells, as assessed by EpCAM and vimentin staining, respectively. Evidence of tumor cell proliferation was provided by Ki67 staining. Furthermore, infiltrating CD4+ and CD8+ lymphocytes were consistently identified within cultured tumor fragments.

The established protocol could easily be adapted to other tumor types, including breast-cancer, glioblastoma, sarcoma and melanoma, with highly effective tissue formation.

Taken together, our results indicate that culture of primary tumor fragments within perfused bioreactors can be successfully achieved over a short-time period in a reproducible manner, and results in the expansion of epithelial and interstitial cells. These ex-vivo generated tissues might mirror features of the original tumor more effectively than 2D or 3D static cultures, and of patient-derived xenografts, thus possibly representing useful tools for the evaluation of sensitivity to chemotherapies or new targeted treatments.

Citation Format: Christian Hirt, Manuele G. Muraro, Valentina Mele, Francesca Amicarella, Celeste Manfredonia, Savas D. Soysal, Simone Muenst, Luigi Mariani, Christoph Kettelhack, Michael Heberer, Giulio C. Spagnoli, Ivan Martin, Giandomenica Iezzi, Adam Papadimitropoulos. Original microenvironment of different cancer types is maintained upon culture of primary tissues in perfused bioreactors. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 328. doi:10.1158/1538-7445.AM2015-328

Abstract 4050: Association of long term NK cell culture and TIMP3 over-expression with NK cell reduced susceptibility to leukemia and epithelial cancer cell induced damage

Allogeneic leukemia and cancer epithelial (CE) cells have been recently shown to induce,in vitro, NK cell abnormalities (NKCA). The latter include NK cell depletion and apoptosis as well as natural cytotoxic receptor (NCR) CD16 down-regulation. The potential negative impact of leukemia and CE cell induced NKCAs on the in vivo anti-tumor activity of NK cells and the limited information about strategies to protect NK cells from NKCAs have prompted us to characterize NKCAs and to develop strategies to counteract them. NKCA induction by leukemia and CE cells is influenced neither by interleukin-2 (IL-2) treatment nor by HLA class I antigen expression, but is abrogated by a long term culture of peripheral blood mononuclear cells (PBMCs) at 37 ºC. Following a 10 day culture of PBMCs, NK cells become resistant to cancer cell induced NKCA but maintain their cytotoxic activity. Actinomycin D restores the susceptibility of long term NK (LTNK) cells to NKCAs suggesting that the generation of resistance to NKCAs requires RNA transcription. TAPI-0, a functional analogue of the tissue inhibitor of metalloproteinases (TIMP) 3, inhibits cancer cell induced NKCAs indicating a role for a restricted number of metalloproteinases (MMPs) in the generation of this phenomenon. This conclusion is supported by the reduced susceptibility to cancer cell induced NKCAs of LTNK cells in which TIMP3 gene and protein are over-expressed. Finally, subcutaneous infusion of IL-2 stimulated LTNK cells inhibited subcutaneous growth of the monoblastic leukemia cells, ML-2 in CB17scid mice while short term, IL-2 stimulated NK cells did not suggesting that LTNK cells have significant anti-leukemia capacity in vivo. This information may contribute to the rational design of targeted strategies to enhance the efficacy of NK cell-based-immunotherapy for the treatment of myeloid leukemias with haploidentical or allogeneic NK cells.

Citation Format: Giuseppe Sconocchia, Roberto Arriga, Sara Caratelli, Giulia Lanzilli, Andrea Coppola, Giulio C. Spagnoli, Adriano Venditti, Sergio Amadori, Davide Lauro, Maria I. Del Principe, Luca Maurillo, Francesco Buccisano, Barbara Capuani, Xinhui Wang, Soldano Ferrone. Association of long term NK cell culture and TIMP3 over-expression with NK cell reduced susceptibility to leukemia and epithelial cancer cell induced damage. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4050. doi:10.1158/1538-7445.AM2015-4050

Abstract 305: An innovative 3D porous scaffold-based perfusion bioreactor system for the in vitro maintenance and expansion of primary breast cancer tissue

Introduction: Development of cancer treatment protocols has traditionally been based on studies in experimental animal models or taking advantage of human established tumor cell lines for in vitro and in vivo assays. Here we present an innovative method to culture breast cancer tissues in porous 3D scaffolds by using a perfusion-based bioreactor system.

Experimental procedures: Freshly excised estrogen-receptor positive breast cancer specimens were fragmented and cultured in a 3D “sandwich-like format” between porous scaffolds under perfusion flow, with “on-line” monitoring of environmental condition. DMEM/F12, supplemented with 10% autologous human serum, was used as a culture medium in the presence or absence of estrogens. The ability of tumor cells to survive and expand into the scaffold in perfusion culture as well as their ability to recapitulate features of the original breast cancer specimens was histologically assessed.

Results: With this innovative method we were able to preserve viability and to promote the expansion of breast cancer cells from surgical specimens together with accompanying stromal and immune cells into the porous scaffold. Expanding cancer cells were viable after 21 days and recapitulating the initial histology with formation of glands. Administration of estrogen to the culture medium was associated with increased expansion of cancer cells into the scaffold starting at 14 days of culture.

Conclusions: Culture of breast cancer tissue in a 3D scaffold-based bioreactor preserves malignant, interstitial and immunocompetent cells present in surgically excised breast cancer samples, thus allowing direct testing of basic cancer research hypotheses in intact, complex human tumor microenvironments. Furthermore, it might allow a direct evaluation of the effects of various treatments on malignant and non-transformed cells. This engineered in vitro model could be extended beyond the context of our primary scientific interest, namely breast cancer, as a broader platform allowing animal-free testing of innovative approaches for the treatment of human malignancies, possibly in the direction of personalized medicine.

Citation Format: Manuele G. Muraro, Simone Muenst, Giulio C. Spagnoli, Daniel Oertli, Walter P. Weber, Savas D. Soysal. An innovative 3D porous scaffold-based perfusion bioreactor system for the in vitro maintenance and expansion of primary breast cancer tissue. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 305. doi:10.1158/1538-7445.AM2015-305

Bioreactor-engineered cancer tissue-like structures mimic phenotypes, gene expression profiles and drug resistance patterns observed "in vivo"

Anticancer compound screening on 2D cell cultures poorly predicts "in vivo" performance, while conventional 3D culture systems are usually characterized by limited cell proliferation, failing to produce tissue-like-structures (TLS) suitable for drug testing. We addressed engineering of TLS by culturing cancer cells in porous scaffolds under perfusion flow. Colorectal cancer (CRC) HT-29 cells were cultured in 2D, on collagen sponges in static conditions or in perfused bioreactors, or injected subcutaneously in immunodeficient mice. Perfused 3D (p3D) cultures resulted in significantly higher (p < 0.0001) cell proliferation than static 3D (s3D) cultures and yielded more homogeneous TLS, with morphology and phenotypes similar to xenografts. Transcriptome analysis revealed a high correlation between xenografts and p3D cultures, particularly for gene clusters regulating apoptotic processes and response to hypoxia. Treatment with 5-Fluorouracil (5-FU), a frequently used but often clinically ineffective chemotherapy drug, induced apoptosis, down-regulation of anti-apoptotic genes (BCL-2, TRAF1, and c-FLIP) and decreased cell numbers in 2D, but only "nucleolar stress" in p3D and xenografts. Conversely, BCL-2 inhibitor ABT-199 induced cytotoxic effects in p3D but not in 2D cultures. Our findings advocate the importance of perfusion flow in 3D cultures of tumor cells to efficiently mimic functional features observed "in vivo" and to test anticancer compounds.

"In vitro" 3D models of tumor-immune system interaction

Interaction between cancer cells and immune system critically affects development, progression and treatment of human malignancies. Experimental animal models and conventional "in vitro" studies have provided a wealth of information on this interaction, currently used to develop immune-mediated therapies. Studies utilizing three-dimensional culture technologies have emphasized that tumor architecture dramatically influences cancer cell-immune system interaction by steering cytokine production and regulating differentiation patterns of myeloid cells, and decreasing the sensitivity of tumor cells to lymphocyte effector functions. Hypoxia and increased production of lactic acid by tumor cells cultured in 3D architectures appear to be mechanistically involved. 3D culture systems could be further developed to (i) include additional cell partners potentially influencing cancer cell-immune system interaction, (ii) enable improved control of hypoxia, and (iii) allow the use of freshly derived clinical cancer specimens. Such advanced models will represent new tools for cancer immunobiology studies and for pre-clinical assessment of innovative treatments.

Abstract 1102: Neutrophils impact on growth and mobility of human colorectal cancer cells

Colorectal cancer (CRC) represents the third most common cancer worldwide, with higher prevalence in developed regions. In Switzerland, about 6000 patients are diagnosed with CRC each year with a mortality rate of approximately 1600 deaths in both sexes, largely exceeding European yearly rates. In clinical practice, administration of monoclonal antibodies (mAb) against Epithelial Growth Factor Receptor (EGFR), alone or in combination with chemotherapy, represents a potential treatment. MAbs have the capacity to induce antibody-dependent cell mediated cytotoxicity through CD16 crosslinking on NK cells. However, NK cells poorly infiltrate human CRC tissues and they are devoid of prognostic value. In contrast, CRC-infiltration by granulocytes has been shown to represent an independent prognostic factor. Since granulocytes are CD16 (FcgRIII)+, the capacity of anti-EGFR immunotherapies to modulate neutrophils functions might crucially influence their clinical outcome. Here we explored direct effects of granulocytes on CRC cell proliferation and mobility “in vitro”.

The scope of this study is to investigate directs effect of neutrophils (N) on CRC cell growth in the presence or absence of anti-EGFR mAb.

First we investigated the effect of N, per se, on CRC cell growth in vitro. We observed that N did not inhibit the proliferation of DLD-1 cells, as assessed by 3HTdR incorporation. However, DLD-1 cells conditioned by human N showed a reduced adhesion on impedance-based cell sensing surfaces. These contrasting results may suggest that in the presence of N, DLD-1 cells could acquire the capacity to proliferate in a contact-independent manner. As a consequence, N-conditioned CRC could become more mobile. Indeed, we observed that DLD-1 cells exhibited an increased migratory capacity after co-culture with N, whereas their capacity to invade matrigel-coated surfaces was not affected. We are currently assessing the migration of CRC conditioned by resting and activated N towards molecularly defined metabolites (i. e. Glucose, Butyrrate), as well as, the expression of genes and proteins involved in cell migration.

Whether EGFR antagonists can impact on tumor cell migration is currently unknown. We therefore plan to study whether anti-EGFR mAbs, which can effectively block the growth of DLD-1 and A431 cells in co-cultured with CD16+ lymphocytes, can also block N-induced CRC migration.

Our data document that N fail to inhibit CRC cell proliferation “in vitro” and increase their mobility. In vivo anti-tumor effects might be related to other components of the tumor microenvironment.

Citation Format: Valeria Governa, Luca Quagliata, Valentina Mele, Christian Hirt, Luigi Terracciano, Giulio C. Spagnoli, Elisabetta Padovan. Neutrophils impact on growth and mobility of human colorectal cancer cells. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1102. doi:10.1158/1538-7445.AM2014-1102

Abstract 4715: OX40 expression improves the prognostic value of CD8 positive lymphocyte density in colorectal carcinoma

Background: The prognostic role of the immunological microenvironment in colorectal cancer (CRC) is well known. Among immune cell types, CD8 positive T lymphocyte infiltration is an established prognostic marker clearly associated with a favorable clinical course of the disease. In contrast, there is limited information about the prognostic role of OX40 positive immune cell infiltration in CRC. However, increasing evidence suggests that OX40 positive immune cell infiltration, as a single biomarker, has a positive prognostic effect in CRC patients. To the best of our knowledge, the impact of the combination of OX40 positive immune cells and CD8 positive T lymphocytes is unknown.

Methods: A tissue microarray composed of 441 biopsies was evaluated for OX40 positive immune cells and CD8 positive T lymphocyte infiltration by immunohistochemistry. The intratumoral number of tumor infiltrating cells positive for OX40 and CD8 antigens was evaluated by 2 independent investigators achieving an optimal concordance rate of 90%. According to the frequency and staining intensity, we identified four subgroups of cell population: OX40low/CD8low, OX40high/CD8low, OX40low/CD8high and OX40high/CD8high. They were correlated with clinicopathological data, and a combined survival analysis was performed.

Results: The mean age of the patients cohort was 69.9 ±10.7 years. A total of 230 (52%) biopsies were from female and 211 (48%) from male CRC patients. Both, OX40 and CD8 positive cell infiltration had a significant, prognostic impact on the clinical outcome of the disease as individual markers (p&lt;0.0001 and p=0.007, respectively). Remarkably, the combination of OX40 and CD8 positive cell infiltration (OX40high/CD8high), significantly enhanced the overall survival of these patients (p&lt;0.0001). These results were maintained after a multivariate Cox regression analysis including T and N stages, grade, vascular invasion, tumor border configuration, microsatellite stability and CD8 and OX40 positive cell infiltration suggesting that this combination is an independent prognostic factor in CRC patients.

Conclusion: The combination OX40 and CD8 positive cell infiltration significantly enhances the overall survival compared to OX40 and CD8 positive cell infiltration alone. OX40high/CD8high positive cell infiltration is an independent, favorable, prognostic marker in CRC.

Citation Format: Benjamin Weixler, Raoul A. Droeser, Roberto Sorge, Tarik Delko, Christian A. Nebiker, Giandomenica Iezzi, Giulio C. Spagnoli, Christoph Kettelhack, Urs W. von Holzen, Daniel Oertli, Luigi Terracciano, Luigi Tornillo, Giuseppe Sconocchia. OX40 expression improves the prognostic value of CD8 positive lymphocyte density in colorectal carcinoma. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4715. doi:10.1158/1538-7445.AM2014-4715

Abstract 2029: Insight of 3D multicellular tumor spheroids for innovative culture models of potential relevance for the screening of anti-CRC compounds

OBJECTIVE - Multicellular tumor spheroid is a well-known method for 3D in-vitro culture that better represent in-vivo condition. We exploited this system to culture human established colorectal cell lines to investigate how the presence or absence of hypoxic and/or necrotic area can influence the gene expression profile and the responsiveness to drugs compared to 2D-culture and in-vivo xenografted cells.

METHODS - HT29 cell line was cultured as MCTS by hanging-drop method. At size-defined time-point spheroids were analyzed for the presence of hypoxic and necrotic areas. The expression of a panel of genes related to tumor progression, metastatic behavior, and drug resistance was evaluated by real time PCR on MCTS at different growth stages in comparison to conventional 2D cultures and xenografts generated upon injection of HT29 cells in immunodeficient mice.

RESULTS - Based on the absence or presence of hypoxic and/or necrotic core, we identified three different MCTS growth stages: stage 1 (MCTS diameter size &lt;200μm) defined by the absence of hypoxia/necrosis, stage 2 (300-350μm) characterized by the presence of hypoxic, but not apoptotic or necrotic areas, and stage 3 (&gt;500μm) identified by the presence of both hypoxic and necrotic areas. The expression of a panel of genes, including putative cancer stem cell markers CD133, CD44, CD24 was found to be upregulated in stage 1 MCTS, as compared to 2D cultures. Most interestingly a further upregulation of these genes was detected in stage 2 and especially in stage 3. Importantly, expression levels in stage 3 were the most similar to those detected in xenografts.

CONCLUSION - Our results showed that culture of CRC cell lines offer the opportunity to investigate in standardized condition different MCTS stages possibly proving an improved model of in-vivo tumor growth. The next generation sequencing and drug-responsiveness of tumor cells cultured in 2D and 3D at different spheroid maturation stages is currently being evaluated.

Citation Format: Silvio Däster, Nunzia Amatruda, Diego Calabrese, Paul Zajac, Giulio C. Spagnoli, Giandomenica Iezzi, Valentina Mele, Manuele Giuseppe Muraro. Insight of 3D multicellular tumor spheroids for innovative culture models of potential relevance for the screening of anti-CRC compounds. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2029. doi:10.1158/1538-7445.AM2014-2029

NK cells and T cells cooperate during the clinical course of colorectal cancer

Recent evidence suggests that natural killer (NK) cells are typically defective in infiltrating solid tumors, with the exception of gastrointestinal stromal tumors (GIST). Interestingly, however, infrequently infiltrating NK cells do not appear to have a direct effect on tumor progression. Here, prompted by the recent evidence that NK cell and T cell crosstalk may trigger, or enhance, tumor antigen-specific immune responses, we have tested the clinical significance of this reciprocal signaling. To this end, a tissue microarray constructed with 1410 colorectal carcinoma (CRC) patient specimens was stained with NK and T cell antigen-specific monoclonal antibodies, utilizing the immunoperoxidase staining technique. Cut-off scores for positive (>4 NK cells) and negative (≤4 NK cells) NK cell CRC patient samples were determined using receiver operating characteristic curve analysis. Using this approach, NK cells were detected in 423 (30%) of the 1410 CRC specimens evaluated. The number of NK cells was >4 in only 132 (9%) of CRC samples. Correlation of the immunohistochemical staining results together with analysis of the clinical course of the disease revealed that the infiltration of colorectal tumors with both NK cells and CD8+ T cells is associated with prolonged patient survival. In contrast, infiltration of tumors with NK cells in combination with CD3⁺ and CD4⁺ T lymphocytes had no detectable effect on the clinical course of the disease. These results suggest that NK cell and CD8⁺ T cell crosstalk in the tumor microenvironment may benefit patient outcome and further, that the enumeration of infiltrating NK and CD8⁺ T cells in CRC tumors may provide useful prognostic information.

GM-CSF Production by Tumor Cells Is Associated with Improved Survival in Colorectal Cancer

PURPOSE

Colorectal cancer infiltration by CD16(+) myeloid cells correlates with improved prognosis. We addressed mechanistic clues and gene and protein expression of cytokines potentially associated with macrophage polarization.

EXPERIMENTAL DESIGN

GM-CSF or M-CSF-stimulated peripheral blood CD14(+) cells from healthy donors were cocultured with colorectal cancer cells. Tumor cell proliferation was assessed by (3)H-thymidine incorporation. Expression of cytokine genes in colorectal cancer and autologous healthy mucosa was tested by quantitative, real-time PCR. A tumor microarray (TMA) including >1,200 colorectal cancer specimens was stained with GM-CSF- and M-CSF-specific antibodies. Clinicopathological features and overall survival were analyzed.

RESULTS

GM-CSF induced CD16 expression in 66% ± 8% of monocytes, as compared with 28% ± 1% in cells stimulated by M-CSF (P = 0.011). GM-CSF but not M-CSF-stimulated macrophages significantly (P < 0.02) inhibited colorectal cancer cell proliferation. GM-CSF gene was expressed to significantly (n = 45, P < 0.0001) higher extents in colorectal cancer than in healthy mucosa, whereas M-CSF gene expression was similar in healthy mucosa and colorectal cancer. Accordingly, IL1β and IL23 genes, typically expressed by M1 macrophages, were expressed to significantly (P < 0.001) higher extents in colorectal cancer than in healthy mucosa. TMA staining revealed that GM-CSF production by tumor cells is associated with lower T stage (P = 0.02), "pushing" growth pattern (P = 0.004) and significantly (P = 0.0002) longer survival in mismatch-repair proficient colorectal cancer. Favorable prognostic effect of GM-CSF production by colorectal cancer cells was confirmed by multivariate analysis and was independent from CD16(+) and CD8(+) cell colorectal cancer infiltration. M-CSF expression had no significant prognostic relevance.

CONCLUSIONS

GM-CSF production by tumor cells is an independent favorable prognostic factor in colorectal cancer.

Mesenchymal stromal cells induce epithelial-to-mesenchymal transition in human colorectal cancer cells through the expression of surface-bound TGF-β

Mesenchymal stem/stromal cells (MSC) are multipotent precursors endowed with the ability to home to primary and metastatic tumor sites, where they can integrate into the tumor-associated stroma. However, molecular mechanisms and outcome of their interaction with cancer cells have not been fully clarified. In this study, we investigated the effects mediated by bone marrow-derived MSC on human colorectal cancer (CRC) cells in vitro and in vivo. We found that MSC triggered epithelial-to-mesenchymal transition (EMT) in tumor cells in vitro, as indicated by upregulation of EMT-related genes, downregulation of E-cadherin and acquisition of mesenchymal morphology. These effects required cell-to-cell contact and were mediated by surface-bound TGF-β newly expressed on MSC upon coculture with tumor cells. In vivo tumor masses formed by MSC-conditioned CRC cells were larger and characterized by higher vessel density, decreased E-cadherin expression and increased expression of mesenchymal markers. Furthermore, MSC-conditioned tumor cells displayed increased invasiveness in vitro and enhanced capacity to invade peripheral tissues in vivo. Thus, by promoting EMT-related phenomena, MSC appear to favor the acquisition of an aggressive phenotype by CRC cells.

FGF2 induces RANKL gene expression as well as IL1β regulated MHC class II in human bone marrow-derived mesenchymal progenitor stromal cells

Objective

Human bone marrow mesenchymal stromal cells (hBM-MSC) are being applied in tissue regeneration and treatment of autoimmune diseases (AD). Their cellular and immunophenotype depend on isolation and culture conditions which may influence their therapeutic application and reflect their in vivo biological functions. We have further characterised the phenotype induced by fibroblast growth factor 2 (FGF2) on healthy donor hBM-MSC focusing on the osteoimmunological markers osteoprotegerin (OPG), receptor activator of nuclear factor kB (RANK), RANK ligand (RANKL) and HLA-DR and their regulation of expression by the inflammatory cytokines IL1β and IFNγ.

Methods

RANK, RANKL, OPG and HLA-DR expression in hBM-MSC expanded under specific culture conditions, were measured by RT-PCR and flow cytometry. MAPKs induction by FGF2, IL1β and IFNγ in hBM-MSC was analysed by immunoblotting and RT-PCR.

Results

In hBM-MSC, OPG expression is constitutive and FGF2 independent. RANKL expression depends on FGF2 and ERK1/2 activation. IL1β and IFNγ activate ERK1/2 but fail to induce RANKL. Only IL1β induces P38MAPK. The previously described HLA-DR induced by FGF2 through ERK1/2 on hBM-MSC, is suppressed by IL1β through inhibition of CIITA transcription. HLA-DR induced by IFNγ is not affected by IL1β in hBM-MSC, but is suppressed in articular chondrocytes and lung fibroblasts.

Conclusions

RANKL expression and IL1β regulated MHC-class II, both induced via activation of the ERK1/2 signalling pathway, are specific for progenitor hBM-MSC expanded in the presence of FGF2. HLA-DR regulated by IL1β and ERK1/2 is observed on hBM-MSC during early expansion without FGF2 suggesting previous in vivo acquisition. Stromal progenitor cells with this phenotype could have an osteoimmunological role during bone regeneration.

Colorectal carcinoma infiltration by myeloperoxidase-expressing neutrophil granulocytes is associated with favorable prognosis

The prognostic relevance of innate immune cells infiltrating colorectal carcinoma lesions is highly debated. By evaluating the expression of myeloperoxidase (MPO) as a marker of neutrophil granulocytes in a large cohort of colorectal carcinoma specimens, we have observed that robust tumor-infiltration by MPO⁺ cells correlates with improved patient survival independently of other histopathological parameters, including disease stage.

Characterization and clinical relevance of ALDHbright populations in prostate cancer

PURPOSE

High aldehyde dehydrogenase (ALDH) has been suggested to selectively mark cells with high tumorigenic potential in established prostate cancer cell lines. However, the existence of cells with high ALDH activity (ALDH(bright)) in primary prostate cancer specimens has not been shown so far. We investigated the presence, phenotype, and clinical significance of ALDH(bright) populations in clinical prostate cancer specimens.

EXPERIMENTAL DESIGN

We used ALDEFLUOR technology and fluorescence-activated cell-sorting (FACS) staining to identify and characterize ALDH(bright) populations in cells freshly isolated from clinical prostate cancer specimens. Expression of genes encoding ALDH-specific isoforms was evaluated by quantitative real-time PCR in normal prostate, benign prostatic hyperplasia (BPH), and prostate cancer tissues. ALDH1A1-specific expression and prognostic significance were assessed by staining two tissue microarrays that included more than 500 samples of BPH, prostatic intraepithelial neoplasia (PIN), and multistage prostate cancer.

RESULTS

ALDH(bright) cells were detectable in freshly excised prostate cancer specimens (n = 39) and were mainly included within the EpCAM((+)) and Trop2((+)) cell populations. Although several ALDH isoforms were expressed to high extents in prostate cancer, only ALDH1A1 gene expression significantly correlated with ALDH activity (P < 0.01) and was increased in cancers with high Gleason scores (P = 0.03). Most importantly, ALDH1A1 protein was expressed significantly more frequently and at higher levels in advanced-stage than in low-stage prostate cancer and BPH. Notably, ALDH1A1 positivity was associated with poor survival (P = 0.02) in hormone-naïve patients.

CONCLUSIONS

Our data indicate that ALDH contributes to the identification of subsets of prostate cancer cells of potentially high clinical relevance.