Abstract 1333: CD4 Th1 cytokines and HER-2/HER-3 blockade induces tumor apoptosis in breast cancer

Background: The therapeutic benefit of blocking HER2/HER3 signaling in breast cancer (BC) has been demonstrated by several studies. We have previously shown that the pleiotropic T-helper type 1 (Th1) cytokines IFN-γ and TNF-α induce senescence in BC cells and that all BC cell lines tested express IFN-γ and TNF-α receptors by western blot analysis. We have also demonstrated an inverse correlation between the HER2 expression level and the senescence induced by the treatment with both cytokines. Moreover, simultaneous HER-2/HER-3 blockade significantly enhanced cytokine-induced senescence. Here, we studied whether these Th1 cytokines induce apoptosis of HER-2 expressing BC cells and assessed the impact of IFN-γ and TNF-α with simultaneous HER-2 and HER-3 blockade on permanent tumor abrogation.

Results: To determine the Th1-mediated effects on HER2high (SK-BR-3, BT-474), HER2intermediate (MCF-7, T-47D), and HER2low (MDA-MB-231) human BC cell lines in vitro, we performed co-culture of increasing number of HER2 Class II peptide-specific CD4+ T-cells (generated by priming CD4+ T cells with HER2 peptide loaded type-1 polarized DCs) with BC cells using a transwell culture system. This resulted in a cell number-dependent apoptosis of SK-BR-3 and MCF-7, but not MDA-MB-231 cells compared with CD4+ T cells primed either with immature dendritic cells (DC) or mature DC plus irrelevant (Class II BRAF) peptide. In addition, SK-BR-3 cells incubated with supernatants from the CD4+ T cells-immature DC or mature DC co-culture demonstrated similar results. Compared with controls, HER2-specific Th1 cells generated a 25-fold increase in SK-BR-3 apoptosis by DAPI staining. Neutralizing antibodies against IFN-γ and TNF-α significantly reduced apoptosis induction. Also, IFN-γ and TNF-α treatment resulted in significant apoptosis of SK-BR-3 and MCF-7, but not MDA-MB-231 cells. However, MDA-MB-231 cells transfected with a wild type HER2 plasmid, were highly susceptible to cytokine-induced apoptosis. Treatment of HER-2-depleted cells (by RNAi) with IFN-γ and TNF-α resulted in an increased apoptotic phenotype. Although the combined treatment of IFN-γ and TNF-α in HER3-depleted cells did not enhanced the apoptosis, the double knock down with HER2 and HER3 RNAi strongly increased apoptosis induction as observed by western blot analysis of active caspase-3 and flow cytometric analysis of Anexin V-PI staining. Interestingly, the double depleted cells treated with IFN-γ alone evidenced slightly higher cleaved caspase-3 levels than TNF-α alone but the combined treatment with both cytokines had a strong synergistic effect.

Conclusions: Our results establish a role for IFN-γ and TNF-α in inducing tumor apoptosis in BC. An effective CD4 Th1 response, combined with HER-2 and HER-3 blockade can significantly drive tumor apoptosis that can be explored as treatment to effectively eliminate residual BC cells and prevent recurrence.

Citation Format: Cinthia Rosemblit, Jashodeep Datta, Erik Berk, Brian J. Czerniecki. CD4 Th1 cytokines and HER-2/HER-3 blockade induces tumor apoptosis in breast cancer. [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 1333. doi:10.1158/1538-7445.AM2015-1333

Abstract 2489: HER2 peptide-specific immunogenicity correlates with pathologic response following HER2-pulsed dendritic cell vaccination for early breast cancer

Introduction:

We have developed an autologous HER2-pulsed dendritic cell (DC) vaccine that induces robust T-cell responses in early breast cancer. We have also previously demonstrated anti-HER2 Th1 responses to select class II peptides are preferentially lost early in HER2pos breast tumorigenesis. We aimed to compare peptide-specific Th1 responses between pathologic complete (pCR) and incomplete responders (<pCR) following HER2-pulsed DC vaccination.

Methods:

Patients with HER2pos DCIS (n = 37) or stage I invasive breast cancer (IBC) (n = 10) received neoadjuvant HER2-pulsed DC vaccine prior to surgery. Specimens were examined for residual disease on pathology. CD4 Th1 responses to 6 HER2 Class II peptides (p42-56, p98-114, p328-345, p776-790, p927-941, p1166-1180) were measured using IFN-γ production by ELISPOT. Th1 response metrics were: (1) anti-HER2 responsivity, (2) response repertoire (i.e. no. of reactive peptides), and (3) cumulative response. Th1 responses post-vaccination were compared between pCR (n = 11) and <pCR (n = 36).

Results:

Forty-three of 47 (91.5%) vaccinated subjects mounted CD4 Th1 responses post-vaccination. Eleven of 47 (23.4%) achieved pCR; no significant difference in pCR rates were observed between IBC and DCIS patients (10% vs 27.0%; p = 0.41). pCR and <pCR patients did not differ by anti-HER2 responsivity (90.9% pCR vs 91.7% 0.05). We previously reported a significant loss of anti-HER2 Th1 responses to p42-56 and p927-941 very early in breast tumorigenesis (i.e. from healthy donors to DCIS ultimately to IBC). In this study, compared to <pCR, pCR patients demonstrated a significantly higher anti-HER2 responsivity (72.7% pCR vs 33.0% <pCR, p = 0.04) and response magnitude (354 vs 110; p = 0.04) to vaccination with p42-56; in addition, there was a trend toward higher response magnitude (318 pCR vs 168 <pCR, p = 0.06) to p927-941 vaccination. No differences were observed in the remaining four peptide responses between pCR and <pCR patients.

Conclusion:

HER2-pulsed DC vaccination induces pathologic responses in early breast cancer patients, supporting further clinical development. The key immunogenic HER2 class II peptides that appear to drive pCR following DC vaccination are incidentally lost very early in tumorigenesis, suggesting that immune restoration targeting these select peptides may enable control of early breast cancer.

Citation Format: Megan E. Fracol, Jashodeep Datta, Shuwen Xu, Lea Lowenfeld, Elizabeth Fitzpatrick, Carolyn Mies, Paul J.L. Zhang, Robert E. Roses, Carla Fisher, Brian J. Czerniecki. HER2 peptide-specific immunogenicity correlates with pathologic response following HER2-pulsed dendritic cell vaccination for early breast cancer. [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 2489. doi:10.1158/1538-7445.AM2015-2489

Identification of Patients with Intermediate Thickness Melanoma at Low Risk for Sentinel Lymph Node Positivity

INTRODUCTION

Sentinel lymph node (SLN) biopsy is recommended for all patients with intermediate-thickness melanomas. We sought to identify such patients at low risk of SLN positivity.

METHODS

All patients with intermediate-thickness melanomas (1.01-4 mm) undergoing SLN biopsy at a single institution from 1995-2011 were included in this retrospective cohort study. Univariate and multivariate logistic regression determined factors associated with a low risk of SLN positivity. Classification and regression tree (CART) analysis was used to stratify groups based on risk of positivity.

RESULTS

Of the 952 study patients, 157 (16.5 %) had a positive SLN. In the multivariate analysis, thickness <1.5 mm (odds ratio [OR] 0.29), age ≥60 (OR 0.69), present tumor-infiltrating lymphocytes (OR 0.60), absent lymphovascular invasion (OR 0.46), and absent satellitosis (OR 0.44) were significantly associated with a low risk of SLN positivity. CART analysis identified thickness of 1.5 mm as the primary cut point for risk of SLN metastasis. Patients with a thickness of <1.5 mm represented 36 % of the total cohort and had a SLN positivity rate of 6.6 % (95 % confidence interval 3.8-9.4 %). In patients with melanomas <1.5 mm in thickness, the presence of additional low risk factors identified 257 patients (75 % of patients with <1.5 mm melanomas) in which the rate of SLN positivity was <5 %.

CONCLUSIONS

Despite a SLN positivity rate of 16.5 % overall, substantial heterogeneity of risk exists among patients with intermediate-thickness melanoma. Most patients with melanoma between 1.01 and 1.5 mm have a risk of SLN positivity similar to that in patients with thin melanomas.

Rationale for a Multimodality Strategy to Enhance the Efficacy of Dendritic Cell-Based Cancer Immunotherapy

Dendritic cells (DC), master antigen-presenting cells that orchestrate interactions between the adaptive and innate immune arms, are increasingly utilized in cancer immunotherapy. Despite remarkable progress in our understanding of DC immunobiology, as well as several encouraging clinical applications – such as DC-based sipuleucel-T for metastatic castration-resistant prostate cancer – clinically effective DC-based immunotherapy as monotherapy for a majority of tumors remains a distant goal. The complex interplay between diverse molecular and immune processes that govern resistance to DC-based vaccination compels a multimodality approach, encompassing a growing arsenal of antitumor agents which target these distinct processes and synergistically enhance DC function. These include antibody-based targeted molecular therapies, immune checkpoint inhibitors, therapies that inhibit immunosuppressive cellular elements, conventional cytotoxic modalities, and immune potentiating adjuvants. It is likely that in the emerging era of “precision” cancer therapeutics, tangible clinical benefits will only be realized with a multifaceted – and personalized – approach combining DC-based vaccination with adjunctive strategies.

Macroscopic optical physiological parameters correlate with microscopic proliferation and vessel area breast cancer signatures

INTRODUCTION

Non-invasive diffuse optical tomography (DOT) and diffuse correlation spectroscopy (DCS) can detect and characterize breast cancer and predict tumor responses to neoadjuvant chemotherapy, even in patients with radiographically dense breasts. However, the relationship between measured optical parameters and pathological biomarker information needs to be further studied to connect information from optics to traditional clinical cancer biology. Thus we investigate how optically measured physiological parameters in malignant tumors such as oxy-, deoxy-hemoglobin concentration, tissue blood oxygenation, and metabolic rate of oxygen correlate with microscopic histopathological biomarkers from the same malignant tumors, e.g., Ki67 proliferation markers, CD34 stained vasculature markers and nuclear morphology.

METHODS

In this pilot study, we investigate correlations of macroscopic physiological parameters of malignant tumors measured by diffuse optical technologies with microscopic histopathological biomarkers of the same tumors, i.e., the Ki67 proliferation marker, the CD34 stained vascular properties marker, and nuclear morphology.

RESULTS

The tumor-to-normal relative ratio of Ki67-positive nuclei is positively correlated with DOT-measured relative tissue blood oxygen saturation (R = 0.89, p-value: 0.001), and lower tumor-to-normal deoxy-hemoglobin concentration is associated with higher expression level of Ki67 nuclei (p-value: 0.01). In a subset of the Ki67-negative group (defined by the 15 % threshold), an inverse correlation between Ki67 expression level and mammary metabolic rate of oxygen was observed (R = -0.95, p-value: 0.014). Further, CD34 stained mean-vessel-area in tumor is positively correlated with tumor-to-normal total-hemoglobin and oxy-hemoglobin concentration. Finally, we find that cell nuclei tend to have more elongated shapes in less oxygenated DOT-measured environments.

CONCLUSIONS

Collectively, the pilot data are consistent with the notion that increased blood is supplied to breast cancers, and it also suggests that less conversion of oxy- to deoxy-hemoglobin occurs in more proliferative cancers. Overall, the observations corroborate expectations that macroscopic measurements of breast cancer physiology using DOT and DCS can reveal microscopic pathological properties of breast cancer and hold potential to complement pathological biomarker information.

Anti-HER2 CD4(+) T-helper type 1 response is a novel immune correlate to pathologic response following neoadjuvant therapy in HER2-positive breast cancer

INTRODUCTION

A progressive loss of circulating anti-human epidermal growth factor receptor-2/neu (HER2) CD4(+) T-helper type 1 (Th1) immune responses is observed in HER2(pos)-invasive breast cancer (IBC) patients relative to healthy controls. Pathologic complete response (pCR) following neoadjuvant trastuzumab and chemotherapy (T + C) is associated with decreased recurrence and improved prognosis. We examined differences in anti-HER2 Th1 responses between pCR and non-pCR patients to identify modifiable immune correlates to pathologic response following neoadjuvant T + C.

METHODS

Anti-HER2 Th1 responses in 87 HER2(pos)-IBC patients were examined using peripheral blood mononuclear cells pulsed with 6 HER2-derived class II peptides via IFN-γ ELISPOT. Th1 response metrics were anti-HER2 responsivity, repertoire (number of reactive peptides), and cumulative response across 6 peptides (spot-forming cells [SFC]/10(6) cells). Anti-HER2 Th1 responses of non-pCR patients (n = 4) receiving adjuvant HER2-pulsed type 1-polarized dendritic cell (DC1) vaccination were analyzed pre- and post-immunization.

RESULTS

Depressed anti-HER2 Th1 responses observed in treatment-naïve HER2(pos)-IBC patients (n = 22) did not improve globally in T + C-treated HER2(pos)-IBC patients (n = 65). Compared with adjuvant T + C receipt, neoadjuvant T + C - utilized in 61.5 % - was associated with higher anti-HER2 Th1 repertoire (p = 0.048). While pCR (n = 16) and non-pCR (n = 24) patients did not differ substantially in demographic/clinical characteristics, pCR patients demonstrated dramatically higher anti-HER2 Th1 responsivity (94 % vs. 33 %, p = 0.0002), repertoire (3.3 vs. 0.3 peptides, p < 0.0001), and cumulative response (148.2 vs. 22.4 SFC/10(6), p < 0.0001) versus non-pCR patients. After controlling for potential confounders, anti-HER2 Th1 responsivity remained independently associated with pathologic response (odds ratio 8.82, p = 0.016). This IFN-γ(+) immune disparity was mediated by anti-HER2 CD4(+)T-bet(+)IFN-γ(+) (i.e., Th1) - not CD4(+)GATA-3(+)IFN-γ(+) (i.e., Th2) - phenotypes, and not attributable to non-pCR patients' immune incompetence, host-level T-cell anergy, or increased immunosuppressive populations. In recruited non-pCR patients, anti-HER2 Th1 repertoire (3.7 vs. 0.5, p = 0.014) and cumulative response (192.3 vs. 33.9 SFC/10(6), p = 0.014) improved significantly following HER2-pulsed DC1 vaccination.

CONCLUSIONS

Anti-HER2 CD4(+) Th1 response is a novel immune correlate to pathologic response following neoadjuvant T + C. In non-pCR patients, depressed Th1 responses are not immunologically "fixed" and can be restored with HER2-directed Th1 immune interventions. In such high-risk patients, combining HER2-targeted therapies with strategies to boost anti-HER2 Th1 immunity may improve outcomes and mitigate recurrence.

Abstract P6-05-03: CD4 Th1 cytokines and HER-2/HER-3 blockade induces tumor senescence in breast cancer

Background: HER-2 a molecular oncodriver in breast tumorigenesis is over expressed in 25% of human breast cancers, and its expression correlates with enhanced tumor aggressiveness. While targeted therapies have improved outcomes many patients become resistant or recur. We have recently established a progressive loss in anti-HER-2 CD4 Th1 responses during disease progression and is associated with outcomes. The pleiotropic Th1 cytokines IFN-γ and TNF-α have diverse effects on tumor epithelial cells. In this study we sought to determine whether these Th1 cytokines induce senescence of HER-2 expressing breast cancer cells and assess the impact of IFN-γ and TNF-α with simultaneous HER-2 and HER-3 blockade.

Results: All breast cancer cell lines tested express IFN-γ and TNF-α receptors measured by western blot analysis. The high and intermediate HER-2 expressing cells are sensitive to tumor senescence induction when treated with combinations of IFN-γ and TNF-α in a dose dependent manner. Low HER-2 expressing cells were less sensitive to senescence induction as measured by positive β-galactosidase activity and the expression of p15INK4b and p16INK4a by western blot. Addition of IFN-γ and TNF-α treatment to HER-2-depleted cells by RNAi resulted in an increase senescent phenotype and was increased further when the cells were double HER-2- and HER-3-depleted. To determine whether CD4 Th1 mediated effects on high HER-2 human breast cancer cell lines, we co-cultured increasing number of HER-2 antigen-primed CD4+ T cells with high HER-2 human breast cancer cells in a transwell cell culture system. This resulted in a dose-dependent senescence of breast cancer cells compared with CD4+ T cells primed either with immature dendritic cells (DC) or mature DC plus irrelevant (Class II BRAF) peptide. In addition, SK-BR-3 breast cancer cells incubated with the supernatant of the CD4+ T cells-immature DC or mature DC co-culture demonstrated similar results. CD4+ Th1-elaborated cytokines IFN-γ and TNF-α in the supernatants were confirmed using ELISA. Blocking antibodies against IFN-γ and TNF-α demonstrated reduced senescence induction.

Conclusions: Our results establish a role for IFN-γ and TNF-α in inducing tumor senescence in breast cancer. An effective CD4 Th1 responses combined with HER-2 and HER-3 blockade can significantly drive tumor senescence in breast cancer that can be explored as treatment to effectively eliminate residual breast cancer cells and prevent recurrence.

Citation Format: Cinthia Rosemblit, Brian J Czerniecki. CD4 Th1 cytokines and HER-2/HER-3 blockade induces tumor senescence in breast cancer [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P6-05-03.

A human ErbB2-specific T-cell receptor confers potent antitumor effector functions in genetically engineered primary cytotoxic lymphocytes

The ErbB2 protein is a member of the tyrosine kinase family of growth factor receptors that is overexpressed in cancers of the breast, ovary, stomach, kidney, colon, and lung, and therefore represents an attractive candidate antigen for targeted cancer immunotherapy. Cytotoxic T lymphocytes specific for various immunogenic ErbB2 peptides have been described, but they often exhibit both poor functional avidity and tumor reactivity. In order to generate potent CD8(+) T cells with specificity for the ErbB2(369-377) peptide, we performed one round of in vitro peptide stimulation of CD8(+) T cells isolated from an HLA-A2(+) patient who was previously vaccinated with autologous dendritic cells pulsed with HLA class I ErbB2 peptides. Using this approach, we enriched highly avid ErbB2-reactive T cells with strong ErbB2-specific, antitumor effector functions. We then stimulated these ErbB2-reactive T cells with ErbB2(+) HLA-A2(+) tumor cells in vitro and sorted tumor-activated ErbB2(369-377) peptide T cells, which allowed for the isolation of a novel T-cell receptor (TCR) with ErbB2(369-377) peptide specificity. Primary human CD8(+) T cells genetically modified to express this ErbB2-specific TCR specifically bound ErbB2(369-377) peptide containing HLA-A2 tetramers, and efficiently recognized target cells pulsed with low nanomolar concentrations of ErbB2(369-377) peptide as well as nonpulsed ErbB2(+) HLA-A2(+) tumor cell lines in vitro. In a novel xenograft model, ErbB2-redirected T cells also significantly delayed progression of ErbB2(+) HLA-A2(+) human tumor in vivo. Together, these results support the notion that redirection of normal T-cell specificity by TCR gene transfer can have potential applications in the adoptive immunotherapy of ErbB2-expressing malignancies.

Progressive loss of anti-HER2 CD4+ T-helper type 1 response in breast tumorigenesis and the potential for immune restoration

Genomic profiling has identified several molecular oncodrivers in breast tumorigenesis. A thorough understanding of endogenous immune responses to these oncodrivers may provide insights into immune interventions for breast cancer (BC). We investigated systemic anti-HER2/neu CD4⁺ T-helper type-1 (Th1) responses in HER2-driven breast tumorigenesis. A highly significant stepwise Th1 response loss extending from healthy donors (HD), through HER2^pos-DCIS, and ultimately to early stage HER2^pos-invasive BC patients was detected by IFNγ ELISPOT. The anti-HER2 Th1 deficit was not attributable to host-level T-cell anergy, loss of immune competence, or increase in immunosuppressive phenotypes (T_reg/MDSCs), but rather associated with a functional shift in IFNγ:IL-10-producing phenotypes. HER2^high, but not HER2^low, BC cells expressing IFNγ/TNF-α receptors were susceptible to Th1 cytokine-mediated apoptosis in vitro, which could be significantly rescued by neutralizing IFNγ and TNF-α, suggesting that abrogation of HER2-specific Th1 may reflect a mechanism of immune evasion in HER2-driven tumorigenesis. While largely unaffected by cytotoxic or HER2-targeted (trastuzumab) therapies, depressed Th1 responses in HER2^pos-BC patients were significantly restored following HER2-pulsed dendritic cell (DC) vaccinations, suggesting that this Th1 defect is not "fixed" and can be corrected by immunologic interventions. Importantly, preserved anti-HER2 Th1 responses were associated with pathologic complete response to neoadjuvant trastuzumab/chemotherapy, while depressed responses were observed in patients incurring locoregional/systemic recurrence following trastuzumab/chemotherapy. Monitoring anti-HER2 Th1 reactivity following HER2-directed therapies may identify vulnerable subgroups at risk of clinicopathologic failure. In such patients, combinations of existing HER2-targeted therapies with strategies to boost anti-HER2 CD4⁺ Th1 immunity may decrease the risk of recurrence and thus warrant further investigation.

CD4(+) T-Helper Type 1 Cytokines and Trastuzumab Facilitate CD8(+) T-cell Targeting of HER2/neu-Expressing Cancers

Vaccination strategies incorporating the immunodominant HLA-A2-restricted HER2/neu-derived peptide 369-377 (HER2369-377) are increasingly utilized in HER2/neu-expressing cancer patients. The failure of postvaccination HER2369-377-specific CD8(+) T cells to recognize HLA-A2(pos)HER2/neu-expressing cells in vitro, however, has been attributed to impaired MHC class I/HLA-A2 presentation observed in HER2/neu-overexpressing tumors. We reconcile this controversy by demonstrating that HER2369-377 is directly recognized by high functional-avidity HER2369-377-specific CD8(+) T cells-either genetically modified to express a novel HER2369-377 TCR or sensitized using HER2369-377-pulsed type 1-polarized dendritic cells (DC1)-on class I-abundant HER2(low), but not class I-deficient HER2(high), cancer cells. Importantly, a critical cooperation between CD4(+) T-helper type-1 (Th1) cytokines IFNγ/TNFα and HER2/neu-targeted antibody trastuzumab is necessary to restore class I expression in HER2(high) cancers, thereby facilitating recognition and lysis of these cells by HER2369-377-specific CD8(+) T cells. Concomitant induction of PD-L1 on HER2/neu-expressing cells by IFNγ/TNF and trastuzumab, however, has minimal impact on DC1-sensitized HER2369-377-CD8(+) T-cell-mediated cytotoxicity. Although activation of EGFR and HER3 signaling significantly abrogates IFNγ/TNFα and trastuzumab-induced class I restoration, EGFR/HER3 receptor blockade rescues class I expression and ensuing HER2369-377-CD8(+) cytotoxicity of HER2/neu-expressing cells. Thus, combinations of CD4(+) Th1 immune interventions and multivalent targeting of HER family members may be required for optimal anti-HER2/neu CD8(+) T-cell-directed immunotherapy.

Optimizing dendritic cell-based approaches for cancer immunotherapy

Dendritic cells (DC) are professional antigen-presenting cells uniquely suited for cancer immunotherapy. They induce primary immune responses, potentiate the effector functions of previously primed T-lymphocytes, and orchestrate communication between innate and adaptive immunity. The remarkable diversity of cytokine activation regimens, DC maturation states, and antigen-loading strategies employed in current DC-based vaccine design reflect an evolving, but incomplete, understanding of optimal DC immunobiology. In the clinical realm, existing DC-based cancer immunotherapy efforts have yielded encouraging but inconsistent results. Despite recent U.S. Federal and Drug Administration (FDA) approval of DC-based sipuleucel-T for metastatic castration-resistant prostate cancer, clinically effective DC immunotherapy as monotherapy for a majority of tumors remains a distant goal. Recent work has identified strategies that may allow for more potent "next-generation" DC vaccines. Additionally, multimodality approaches incorporating DC-based immunotherapy may improve clinical outcomes.

Radiation as immunomodulator: implications for dendritic cell-based immunotherapy

The last decade has witnessed significant progress in the field of cancer immunotherapy. This has, in part, been driven by a growing recognition that elements of the innate immune response can be harnessed to induce robust immunity against tumor-associated targets. Nonetheless, as clinically effective immunotherapy for the majority of cancers remains a distant goal, attention has shifted toward multimodality approaches to cancer therapy, sometimes combining novel immunotherapeutics and conventional therapeutics. The traditional view of radiation therapy as immunosuppressive has been challenged, prompting a re-evaluation of its potential as an adjunct to, or even a component of immunotherapy. Radiation therapy may enhance expression of tumor-associated antigens, induce targeting of tumor stroma, diminish regulatory T-cell activity and activate effectors of innate immunity such as dendritic cells through Toll-like receptor (TLR)-dependent mechanisms. Here, we review recent progress in the field of dendritic cell-based immunotherapy, evidence for radiation-induced antitumor immunity and TLR signaling and the results of efforts to rationally integrate radiation into dendritic cell-based immunotherapy strategies.

Optically measured microvascular blood flow contrast of malignant breast tumors

Microvascular blood flow contrast is an important hemodynamic and metabolic parameter with potential to enhance in vivo breast cancer detection and therapy monitoring. Here we report on non-invasive line-scan measurements of malignant breast tumors with a hand-held optical probe in the remission geometry. The probe employs diffuse correlation spectroscopy (DCS), a near-infrared optical method that quantifies deep tissue microvascular blood flow. Tumor-to-normal perfusion ratios are derived from thirty-two human subjects. Mean (95% confidence interval) tumor-to-normal ratio using surrounding normal tissue was 2.25 (1.92–2.63); tumor-to-normal ratio using normal tissues at the corresponding tumor location in the contralateral breast was 2.27 (1.94–2.66), and using normal tissue in the contralateral breast was 2.27 (1.90–2.70). Thus, the mean tumor-to-normal ratios were significantly different from unity irrespective of the normal tissue chosen, implying that tumors have significantly higher blood flow than normal tissues. Therefore, the study demonstrates existence of breast cancer contrast in blood flow measured by DCS. The new, optically accessible cancer contrast holds potential for cancer detection and therapy monitoring applications, and it is likely to be especially useful when combined with diffuse optical spectroscopy/tomography.

Dendritic cells matured in the presence of TLR ligands overcome the immunosuppressive functions of regulatory T cells

Toll like receptor (TLR)-stimulated dendritic cells (DCs) are able to overcome the inhibitory activity of regulatory T cells (Tregs) and induce the proliferation of effector T cells. TLR-activated DCs secrete a soluble factor and act directly on Tregs to convert them into interferon γ-secreting T_H1-like cells that express the transcription factor T-bet.

Dendritic Cell-Induced Th1 and Th17 Cell Differentiation for Cancer Therapy

The success of cellular immunotherapies against cancer requires the generation of activated CD4⁺ and CD8⁺ T-cells. The type of T-cell response generated (e.g., Th1 or Th2) will determine the efficacy of the therapy, and it is generally assumed that a type-1 response is needed for optimal cancer treatment. IL-17 producing T-cells (Th17/Tc17) play an important role in autoimmune diseases, but their function in cancer is more controversial. While some studies have shown a pro-cancerous role for IL-17, other studies have shown an anti-tumor function. The induction of polarized T-cell responses can be regulated by dendritic cells (DCs). DCs are key regulators of the immune system with the ability to affect both innate and adaptive immune responses. These properties have led many researchers to study the use of ex vivo manipulated DCs for the treatment of various diseases, such as cancer and autoimmune diseases. While Th1/Tc1 cells are traditionally used for their potent anti-tumor responses, mounting evidence suggests Th17/Tc17 cells should be utilized by themselves or for the induction of optimal Th1 responses. It is therefore important to understand the factors involved in the induction of both type-1 and type-17 T-cell responses by DCs.

Prognosis of patients with melanoma and microsatellitosis undergoing sentinel lymph node biopsy

INTRODUCTION

Melanoma microsatellitosis is classified as stage IIIB/C disease and is associated with a poor prognosis. Prognostic factors within this group, however, have not been well characterized.

METHODS

We performed a retrospective analysis of 1,621 patients undergoing sentinel lymph node (SLN) biopsy at our institution (1996-2011) to compare patients with (n = 98) and patients without (n = 1,523) microsatellites. Univariate and multivariate logistic and Cox regression analyses were used to identify factors associated with SLN positivity and melanoma-specific survival (MSS) in patients with microsatellites.

RESULTS

Patients with microsatellites were older and had lesions with higher Clark level and greater thickness that more frequently had mitoses, ulceration, and lymphovascular invasion (LVI) (all p < 0.0001). In microsatellite patients, the SLN positivity rate was 43 %. Lesional ulceration (odds ratio [OR] = 2.9, 95 % confidence interval [CI] 1.5-8.6), absent tumor infiltrating lymphocytes (OR = 2.8, 95 % CI 1.1-7.1), and LVI (OR = 3.3, 95 % CI 1.7-10) were significantly associated with SLN positivity by multivariate analysis. With a median follow-up of 4.5 years in survivors, ulceration (hazards ratio [HR] = 3.4, 95 % CI 1.5-7.8) and >1 metastatic LN (HR = 2.7, 95 % CI 1.1-6.6) were significantly associated with decreased MSS by multivariate analysis. In patients without these prognostic factors, the 5-year MSS was 90 % (n = 49) compared with 50 % (n = 23) among patients with ulceration only, 51 % (n = 12) in those with >1 metastatic LN only, or 25 % in those with both (n = 14, p < 0.01).

DISCUSSION

Microsatellitosis was frequently associated with multiple adverse pathologic features. In the absence of ulceration and >1 metastatic LN; however, the outcome for patients with microsatellites compared favorably to stage IIIB patients overall.

Inhibition of CD4+CD25+ regulatory T cell function and conversion into Th1-like effectors by a Toll-like receptor-activated dendritic cell vaccine

Despite the success of vaccines against some microbial pathogens, their utility in the prevention and treatment of cancer has thus far been limited. We have previously demonstrated that vaccination with dendritic cells activated with the TLR-4 ligand LPS and IFN-γ promotes an antigen-specific anti-tumor response that prevents tumor recurrence. To evaluate this mechanistically, we here studied the effects of this TLR-activated DC on regulatory T cell activity. Dendritic cells activated with LPS and IFN- γ negated the effects of regulatory T cells on responder cell proliferation. Restoration of responder cell proliferation was noted when TLR-activated dendritic cells were separated from both regulators and responders by a semi-permeable membrane. The effect is therefore mediated by a soluble factor but was independent of both IL-6 and IL-12. Furthermore, the soluble mediator appeared to act at least in part on the regulators themselves rather than responder cells exclusively. Because recent studies have demonstrated conversion of T regulatory cells into IL-17-producing effectors, we further questioned whether the TLR-activated dendritic cell would induce cytokine production and effector function in our system. We found that regulators produced a substantial amount of IFN- γ in the presence of TLR-activated dendritic cells but not immature dendritic cells. IFN-γ production was associated with upregulation of the Th1 transcriptional regulator T-bet, and a significant fraction of IFN-γ-producing regulators coexpressed T-bet and FoxP3. While the effects of the LPS-activated dendritic cell on responder cell proliferation were IL-12 independent, upregulation of T-bet was inhibited by a neutralizing anti-IL-12 antibody. Collectively, these and prior data suggest that varying innate immune signals may direct the phenotype of the immune response in part by inhibiting suppressor T cells and promoting differentiation of these regulators into particular subsets of effectors.

Clark level risk stratifies patients with mitogenic thin melanomas for sentinel lymph node biopsy

BACKGROUND

The role for sentinel lymph node biopsy (SLNB) in patients with thin melanoma (≤1 mm) remains controversial. We examined a large cohort of patients with thin melanoma to better define predictors of SLN positivity.

METHODS

From 1995 to 2011, 781 patients with thin primary melanoma and evaluable clinicopathologic data underwent SLNB at our institution. Predictors of SLN positivity were determined using univariate and multivariate regression analyses, and patients were risk-stratified using a classification and regression tree (CART) analysis.

RESULTS

In the study cohort (n = 781), 29 patients (3.7%) had nodal metastases. In the univariate analysis, mitotic rate [odds ratio (OR) = 8.11, p = 0.005], Clark level (OR 4.04, p = 0.003), and thickness (OR 3.33, p = 0.011) were significantly associated with SLN positivity. In the multivariate analysis, MR (OR 7.01) and level IV-V (OR 3.45) remained significant predictors of SLN positivity. CART analysis initially stratified lesions by mitotic rate; nonmitogenic lesions (n = 273) had a 0.7% SLN positivity rate versus 5.6% in mitogenic lesions (n = 425). Mitogenic lesions were further stratified by Clark level; patients with level II-III had a 2.9% SLN positivity rate (n = 205) versus 8.2% with level IV-V (n = 220). With median follow-up of 6.3 years, five SLN-negative patients developed nodal recurrence and four SLN-positive patients died of disease.

CONCLUSIONS

SLN positivity is low in patients with thin melanoma (3.7%) and exceedingly so in nonmitogenic lesions (0.7%). Appreciable rates of SLN positivity can be identified in patients with mitogenic lesions, particularly with concurrent level IV-V regardless of thickness. These factors may guide appropriate selection of patients with thin melanoma for SLNB.

Abstract B087: HER-2/neu expression regulates the immune response and tumor senescence in breast cancer

Background: Over-expression of the receptor tyrosine kinase ErbB2 (HER-2) has been widely implicated in malignant transformation, cell survival, motility and invasion in breast cancers. Intermediate expression of HER-2 has been identified in luminal breast cancer stem cells. HER-2 over-expression down regulates major histocompatibility complex class I molecules (MHCI) expression in breast cancer cells.

Results: We investigated the expression of HER-2 in various HER-2 expressing cell lines and measured HLA A-2 MHC class I expression. High Her-2 expressing cell lines SKBR3 and SKOVA3 and intermediate expressing cell lines MCF7 demonstrated extremely low HLA A-2 expression, while low Her-2 expressing MDAMB231 demonstrated low HER-2 expression and high HLA A2 expression. Anti-HER-2 CD8 T cells recognize the latter cells but not high or intermediate expressing HER-2 expressing cells. Treatment of intermediate expressing cell lines but not high HER-2 expressing cells with interferon-gamma; (IFN- gamma) and TNF-alpha; result in markedly increased HLA A2 expression and 3 fold increase in CD8 T cell killing of the MCF7 cells. Treatment of high expressing HER-2 cells with trastuzumab but not lapatinib decreased HER-2 expression and combined with IFN-gamma; and TNF-alpha; result in increased HLA- A2 expression and dramatic increase in CD8 T cell recognition. In contrast, high and intermediate HER-2 expressing cells are sensitive to lysis and tumor senescence induction when treated with combinations of IFN-gamma; and TNF-alpha; in a dose dependent manner. Low HER-2 expressing cells are less sensitive to senescence induction.

Conclusions: In conclusion, our results establish a potential role for HER-2 in regulating the immune response against breast cancer and suggest that CD8 T cells are more effective in eliminating low and intermediate HER-2 expressing cells while CD4 T cell derived IFN-gamma; and TNF-alpha; together with trastuzumab may be more effective in eliminating high expressing HER-2 breast cancer cells and inducing tumor senescence preventing recurrence.

Citation Format: Cinthia Rosemblit, Jessica Cintolo-Gonzalez, Shuwen Xu, Brian J. Czerniecki. HER-2/neu expression regulates the immune response and tumor senescence in breast cancer. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Breast Cancer Research: Genetics, Biology, and Clinical Applications; Oct 3-6, 2013; San Diego, CA. Philadelphia (PA): AACR; Mol Cancer Res 2013;11(10 Suppl):Abstract nr B087.

Racial disparities in the use of outpatient mastectomy

BACKGROUND

Racial disparities exist within many domains of cancer care. This study was designed to identify differences in the use of outpatient mastectomy (OM) based on patient race.

METHODS

We identified patients in the American College of Surgeons National Surgical Quality Improvement Program Participant Use File (during the years 2007-2010) who underwent a mastectomy. The association between mastectomy setting, patient race, patient age, American Society of Anesthesiology physical status classification, functional status, mastectomy type, and hospital teaching status was determined using the chi-square test. A multivariable logistic regression analysis was developed to assess the relative odds of undergoing OM by race, with adjustment for potential confounders.

RESULTS

We identified 47,318 patients enrolled in the American College of Surgeons National Surgical Quality Improvement Program Participant Use File who underwent a mastectomy during the study time frame. More than half (62.6%) of mastectomies were performed in the outpatient setting. All racial minorities had lower rates of OM, with 63.8% of white patients; 59.1% of black patients; 57.4% of Asian, Native Hawaiian, or Pacific Islander patients; and 43.9% of American Indian or Alaska Native patients undergoing OM (P < 0.001). After adjustment for multiple confounders, black patients, American Indian or Alaska Native patients, and those of unknown race were all less likely to undergo OM (odds ratio [OR], 0.86; 95% confidence interval [CI], 0.80-0.93; OR, 0.55; 95% CI, 0.41-0.72; and OR, 0.70; 95% CI, 0.64-0.76, respectively) compared with white patients.

CONCLUSIONS

Disparities exist in the use of OM among racial minorities. Further studies are needed to identify the role of cultural preferences, physician attitudes, and insurer encouragements that may influence these patterns of use.