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Phenotypic characterization of CSPG4-CAR.CIK

PDF file - 193K, Representative flow cytometry analysis of a CIK cell culture generated from PBMC from mMel patients.

Phenotypic characterization of CSPG4-CAR.CIK and CSPG4-CAR.T

NTD.CIK vs S5 - 3D-RECONSTRUCTION

Purpose: We investigate the unknown tumor-killing activity of cytokine-induced killer (CIK) cells against autologous metastatic melanoma and the elusive subset of putative cancer stem cells (mCSC).Experimental Design: We developed a preclinical autologous model using same patient-generated CIK cells and tumor targets to consider the unique biology of each patient/tumor pairing. In primary tumor cell cultures, we visualized and immunophenotypically defined a putative mCSC subset using a novel gene transfer strategy that exploited their exclusive ability to activate the promoter of stemness gene Oct4.Results: The CIK cells from 10 patients with metastatic melanoma were successfully expanded (median, 23-fold; range, 11–117). Primary tumor cell cultures established and characterized from the same patients were used as autologous targets. Patient-derived CIK cells efficiently killed autologous metastatic melanoma [up to 71% specific killing (n = 26)]. CIK cells were active in vivo against autologous melanoma, resulting in delayed tumor growth, increased necrotic areas, and lymphocyte infiltration at tumor sites. The metastatic melanoma cultures presented an average of 11.5% ± 2.5% putative mCSCs, which was assessed by Oct4 promoter activity and stemness marker expression (Oct4, ABCG2, ALDH, MITF). Expression was confirmed on mCSC target molecules recognized by CIK cells (MIC A/B; ULBPs). CIK tumor killing activity against mCSCs was intense (up to 71%, n = 4) and comparable with results reported against differentiated metastatic melanoma cells (P = 0.8).Conclusions: For the first time, the intense killing activity of CIK cells against autologous metastatic melanoma, including mCSCs, has been shown. These findings move clinical investigation of a new immunotherapy for metastatic melanoma, including mCSCs, closer. Clin Cancer Res; 19(16); 4347–58. ©2013 AACR.

PDF file - 147K, Representative flow cytometry analysis of melanoma primary cell cultures. assessment of CD117 (aka c-kit) and MCSP; c) assessment of MIC A/B and ULBP2; d) assessment of ULBP1 and ULBP3 expression; e) expression assessment of CD34 and VEGFR1 expression; f) assessment of intracellular Oct4 expression in fixed and permeabilized cells; g) assessment of ABCG2 expression; h) assessment of ALDH activity in cells stained with FITC ALDH substrate; i) assessment of MITF negativity in fixed and permeabilized cells stained with a primary specific antibody unconjugated and a PE conjugated secondary antibody; k) assessment of CD117 (also known as c-kit) and MCSP in mMel6, notably highly positive for CD117 expression.

Purpose:No effective therapy is available for unresectable soft-tissue sarcomas (STS). This unmet clinical need prompted us to test whether chondroitin sulfate proteoglycan 4 (CSPG4)-specific chimeric antigen receptor (CAR)-redirected cytokine-induced killer lymphocytes (CAR.CIK) are effective in eliminating tumor cells derived from multiple STS histotypes in vitro and in immunodeficient mice.Experimental Design:The experimental platform included patient-derived CAR.CIK and cell lines established from multiple STS histotypes. CAR.CIK were transduced with a retroviral vector encoding second-generation CSPG4-specific CAR (CSPG4-CAR) with 4-1BB costimulation. The functional activity of CSPG4-CAR.CIK was explored in vitro, in two- and three-dimensional STS cultures, and in three in vivo STS xenograft models.Results:CSPG4-CAR.CIK were efficiently generated from patients with STS. CSPG4 was highly expressed in multiple STS histotypes by in silico analysis and on all 16 STS cell lines tested by flow cytometry. CSPG4-CAR.CIK displayed superior in vitro cytolytic activity against multiple STS histotypes as compared with paired unmodified control CIK. CSPG4-CAR.CIK also showed strong antitumor activity against STS spheroids; this effect was associated with tumor recruitment, infiltration, and matrix penetration. CSPG4-CAR.CIK significantly delayed or reversed tumor growth in vivo in three STS xenograft models (leiomyosarcoma, undifferentiated pleomorphic sarcoma, and fibrosarcoma). Tumor growth inhibition persisted for up to 2 weeks following the last administration of CSPG4-CAR.CIK.Conclusions:This study has shown that CSPG4-CAR.CIK effectively targets multiple STS histotypes in vitro and in immunodeficient mice. These results provide a strong rationale to translate the novel strategy we have developed into a clinical setting.

CSPG4-CAR.CIK vs S5 - CYTOTOXICITY

Fig. S3. In NRASQ61 mutant cells MEKi alone leads to highest levels of PD1+ melanoma cells. Representative flow cytometry plots of a NRASQ61 mutant melanoma cell line (SKMEL2) treated with dabrafenib [1mcM], trametinib [5nM], the combination of dabrafenib + trametinib [1mcM+5nM], and fotemustine [50mcg/ml] for 96 hours. DAPI staining was used to identify viable cells. PD1, PDL1, PDL2 plots were performed considering only viable cells.

PDF file - 143K, Primary melanoma cell targets.

Supplementary Figure S2: Immunophenotype of patient-derived CIK cells and CIK cell in vitro activity

DNA extraction and Sanger Sequencing In vivo Limiting Dilution Assay Cell growth inhibition assay Analysis of LV.Oct4.eGFP integration in eGFP positive and negative cell fractions

NTD.CIK vs S5 - INFILTRATION

PDF file - 64K

PDF file - 122K, Representative cell sorting plots of LV-oct4.eGFP transduced cells.

CSPG4-CAR.CIK vs S5 - 3D-RECONSTRUCTION

CSPG4-CAR.CIK in vitro cytolytic activity against 12 distinct STS histotypes

PDF file - 117K, Expression level of ABCG2 (a), NKG2D ligands MIC A/B (b) and ULBP2 (c) in LV-oct4-eGFP transduced cells.

PDF file - 81K, Representative flow cytometry analysis of melanoma primary transduced cells.

CSPG4-CAR.CIK vs S5 - INFILTRATION

Supplementary Table 1: Patients Characteristics Supplementary Table 2: Comparative transduction of melanoma cell cultures

Supplementary Figure S5:Tumor infiltration by CIK cells

NTD.CIK vs S5 -CYTOTOXICITY

Purpose: The MHC-unrestricted activity of cytokine-induced killer (CIK) cells against chemo-surviving melanoma cancer stem cells (mCSC) was explored, as CSCs are considered responsible for chemoresistance and relapses.Experimental Design: Putative mCSCs were visualized by engineering patient-derived melanoma cells (MC) with a lentiviral vector encoding eGFP under expression control by stemness gene promoter oct4. Their stemness potential was confirmed in vivo by limiting dilution assays. We explored the sensitivity of eGFP+ mCSCs to chemotherapy (CHT), BRAF inhibitor (BRAFi) or CIK cells, as single agents or in sequence, in vitro. First, we treated MCs in vitro with fotemustine or dabrafenib (BRAF-mutated cases); then, surviving MCs, enriched in mCSCs, were challenged with autologous CIK cells. CIK cell activity against chemoresistant mCSCs was confirmed in vivo in two distinct immunodeficient murine models.Results: We visualized eGFP+ mCSCs (14% ± 2.1%) in 11 MCs. The tumorigenic precursor rate in vivo was higher within eGFP+ MCs (1/42) compared with the eGFP− counterpart (1/4,870). In vitro mCSCs were relatively resistant to CHT and BRAFi, but killed by CIK cells (n = 11, 8/11 autologous), with specific lysis ranging from 95% [effector:tumor ratio (E:T), 40:1] to 20% (E:T 1:3). In vivo infusion of autologous CIK cells into mice bearing xenografts from three distinct melanomas demonstrated significant tumor responses involving CHT-spared eGFP+ mCSCs (P = 0.001). Sequential CHT–immunotherapy treatment retained antitumor activity (n = 12, P = 0.001) reducing mCSC rates (P = 0.01).Conclusions: These findings are the first demonstration that immunotherapy with CIK cells is active against autologous mCSCs surviving CHT or BRAFi. An experimental platform for mCSC study and rationale for CIK cells in melanoma clinical study is provided. Clin Cancer Res; 23(9); 2277–88. ©2016 AACR.

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Supplemental Table 1. Phenotypic characterization of patient-derived CSPG4-CAR.CIK and unmodified NTD.CIK

CSPG4-CAR.CIK show antitumor activity in STS xenograft models

Th1 and Th2 cytokine production by CSPG4-CAR.CIK and CSPG4-CAR.T

Cytokine-induced killer lymphocytes (CIK) are a promising alternative to conventional donor lymphocyte infusion (DLI), following allogeneic haematopoietic cell transplantation (HCT), due to their intrinsic anti-tumour activity and reduced risk of graft-versus-host disease (GVHD). We explored the feasibility, anti-leukaemic activity and alloreactive risk of CIK generated from full-donor chimaeric (fc) patients and genetically redirected by a chimeric antigen receptor (CAR) (fcCAR.CIK) against the leukaemic target CD44v6. fcCAR.CIK were successfully ex-vivo expanded from leukaemic patients in complete remission after HCT confirming their intense preclinical anti-leukaemic activity without enhancing the alloreactivity across human leukocyte antigen (HLA) barriers. Our study provides translational bases to support clinical studies with fcCAR.CIK, a sort of biological bridge between the autologous and allogeneic sources, as alternative DLI following HCT.

Purpose of this study is to explore the preclinical efficacy of Chondroitin Sulfate Proteoglycan 4 (CSPG4)-specific CAR-engineered Cytokine-Induced Killer lymphocytes (CIK) to eradicate melanoma cells with defective HLA class I (HLA-I). The latter abnormality plays a major role in clinical resistance to Checkpoint Inhibitors (CI). CSPG4 was selected as the target because of its high expression on melanoma and its restricted distribution in normal tissues. Our approach is based on CAR.CIK redirected against CSPG4. CIK, ex vivo expanded T-NK lymphocytes endowed with intrinsic HLA-independent antitumor activity, were used as effectors. Experimental procedure. CAR.CIK were generated by retroviral transduction of patient derived PBMC with a vector encoding a 2nd generation CSPG4-CAR with 4-1BB co-stimulation. Surface HLA-I expression was evaluated by flow cytometry on melanoma cell lines (Mel), derived by surgical biopsies. These cells also served as targets for CSPG4 CAR.CIK. The activity of CSPG4 CAR.CIK was analyzed in vitro and in immunodeficient mice grafted with a patient-derived HLA-defective melanoma. Mice were treated intravenously with 3x106 CAR.CIK (5 cells infusions in total). Results. CAR.CIK were efficiently generated from 4 melanoma patients. Mean expression of CSPG4-CAR was 48±8%, the rate of ex vivo expansion (84 fold) and phenotypic characteristics (CD3+CD8+=71±13%, CD3+ CD56+=22.5±13%, NKG2D+= 68±32.3%) were comparable with unmodified controls. Membrane HLA-I molecules were detected in 23/24 Mel samples, with a variable membrane density per cell (median 21232, range 787-49871). Sample Mel17 did not express HLA-I because of a start lost mutation (p.Met1Ile) in β2microglobulin. CSPG4 was intensely expressed by all Mel (78±5%), with no correlation to HLA-I levels. CSPG4 CAR.CIK efficiently killed 10 Mel samples in vitro, including Mel17 (HLA-I negative) and 2 Mel with the lowest HLA-I density (Mel71, Mel72). Mean Mel-specific killing by CSPG4 CAR.CIK was significantly higher compared with unmodified CIK especially at low effector/target (E/T) ratios (85% vs 40% at E/T=1:1; 46% vs 9% at E/T=1:8, p Conclusions. We reported the activity of CSPG4 CAR.CIK against melanoma, including those with low or defective HLA-I expression. CIK may provide a valid platform for CAR-based strategies against melanoma and solid tumors in general. Our data provide the rationale to implement clinical studies exploring the proposed strategy in melanoma patients not responding or relapsing after immunotherapy with CI. Citation Format: Giulia Cattaneo, Lidia Giraudo, Loretta Gammaitoni, Ilenia Iaia, Fabrizio Carnevale-Schianca, Alberto Pisacane, Enrico Berrino, Caterina Marchiò, Luca Paruzzo, Andrea Michela Biolato, Chiara Donini, Marco Basiricò, Elisa Landoni, Soldano Ferrone, Valeria Leuci, Massimo Aglietta, Gianpietro Dotti, Dario Sangiolo. CSPG4-specific CAR.CIK lymphocyte-based immunotherapy to eliminate HLA class I-defective melanoma tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2812.

Purpose: No effective therapy is available for unresectable soft-tissue sarcomas (STS). This unmet clinical need prompted us to test whether chondroitin sulfate proteoglycan 4 (CSPG4)-specific chimeric antigen receptor (CAR)-redirected cytokine-induced killer lymphocytes (CAR.CIK) are effective in eliminating tumor cells derived from multiple STS histotypes in vitro and in immunodeficient mice. Experimental Design: The experimental platform included patient-derived CAR.CIK and cell lines established from multiple STS histotypes. CAR.CIK were transduced with a retroviral vector encoding second-generation CSPG4-specific CAR (CSPG4-CAR) with 4-1BB costimulation. The functional activity of CSPG4-CAR.CIK was explored in vitro, in two- and three-dimensional STS cultures, and in three in vivo STS xenograft models. Results: CSPG4-CAR.CIK were efficiently generated from patients with STS. CSPG4 was highly expressed in multiple STS histotypes by in silico analysis and on all 16 STS cell lines tested by flow cytometry. CSPG4-CAR.CIK displayed superior in vitro cytolytic activity against multiple STS histotypes as compared with paired unmodified control CIK. CSPG4-CAR.CIK also showed strong antitumor activity against STS spheroids; this effect was associated with tumor recruitment, infiltration, and matrix penetration. CSPG4-CAR.CIK significantly delayed or reversed tumor growth in vivo in three STS xenograft models (leiomyosarcoma, undifferentiated pleomorphic sarcoma, and fibrosarcoma). Tumor growth inhibition persisted for up to 2 weeks following the last administration of CSPG4-CAR.CIK. Conclusions: This study has shown that CSPG4-CAR.CIK effectively targets multiple STS histotypes in vitro and in immunodeficient mice. These results provide a strong rationale to translate the novel strategy we have developed into a clinical setting.

Purpose: BRAF and MEK inhibitors (BRAF/MEKi) favor melanoma-infiltrating lymphocytes, providing the rationale for current combinatorial trials with anti–PD-1 antibody. A portion of melanoma cells may express PD-1, and anti–PD-1 antibody could have a direct antitumor effect. Here, we explore whether BRAF/MEKi modulate rates of PD-1+ melanoma cells, supporting an additional—lymphocyte-independent—basis for their therapeutic combination with anti–PD-1 antibody. Experimental Design: With data mining and flow cytometry, we assessed PD-1, PD-L1/2 expression on melanoma cell lines (CCLE, N = 61; validation cell lines, N = 7) and melanoma tumors (TCGA, N = 214). We explored in vitro how BRAF/MEKi affect rates of PD-1+, PD-L1/2+ melanoma cells, and characterized the proliferative and putative stemness features of PD-1+ melanoma cells. We tested the functional lymphocyte-independent effect of anti–PD-1 antibody alone and in combination with BRAF/MEKi in vitro and in an in vivo immunodeficient murine model. Results: PD-1 is consistently expressed on a small subset of melanoma cells, but PD-1+ cells increase to relevant rates during BRAF/MEKi treatment [7.3% (5.6–14.2) vs. 1.5% (0.7–3.2), P = 0.0156; N = 7], together with PD-L2+ melanoma cells [8.5% (0.0–63.0) vs. 1.5% (0.2–43.3), P = 0.0312; N = 7]. PD-1+ cells proliferate less than PD-1− cells (avg. 65% less; t = 7 days) and are preferentially endowed with stemness features. In vivo, the direct anti-melanoma activity of PD-1 blockage as monotherapy was negligible, but its association with BRAF/MEKi significantly delayed the development of drug resistance and tumor relapse. Conclusions: BRAF/MEKi increase the rates of PD-1+ melanoma cells that may sustain tumor relapse, providing a lymphocyte-independent rationale to explore combinatory strategies with anti–PD-1 antibody. Clin Cancer Res; 24(14); 3377–85. ©2018 AACR.

Simple Summary Limited therapeutic results of immune checkpoint inhibitors in definite tumor settings, such as melanoma, call for alternative or complementary approaches. Among these, adoptive cell therapy (ACT) by means of HLA-independent tumor killer lymphocytes is a promising approach. We aimed at developing a pre-clinical 3D model to investigate and visualize the interaction between tumor and immune effectors in melanoma. To this aim, we employed Cytokine-Induced Killer cells (CIK) and NK-92 on patient-derived melanoma samples. By means of imaging-based methods, we measured the effector recruitment on the 3D targets, their infiltration, and cytotoxic activity. Our results and methodologies can be easily generalized to other effectors and other classes of tumors and help elucidate fundamental questions on the basic biology and kinetics of immune effector recruitment in a realistic 3D setting mimicking a solid tumor. Abstract Cancer adoptive cell therapy (ACT) with HLA-independent tumor killer lymphocytes is a promising approach, with intrinsic features potentially addressing crucial tumor-escape mechanisms of checkpoint inhibitors. Cytokine-induced Killer (CIK) and Natural Killer (NK) lymphocytes share similar tumor-killing mechanisms, with preclinical evidence of intense activity against multiple solid tumors and currently testing in clinical studies. To improve the effective clinical translation of such ACT approaches, several fundamental questions still need to be addressed within appropriate preclinical contexts, capable of overcoming limitations imposed by most traditional two-dimensional assays. Here, we developed a novel experimental approach to explore, dissect, and visualize the interactions of CIK and NK lymphocytes with melanoma tumors in vitro in 3D. Primary melanoma cells were assembled into small tumors that were dispersed in a 3D matrix and challenged with patient-derived CIK or the NK-92 cell line. By means of imaging-based methods, we reported, visualized, and quantitatively measured the recruitment of CIK and NK on the 3D targets, their infiltration, and cytotoxic activity. Our results support the effective tumor recruitment and tumor infiltration by CIK and NK. Such features appeared dependent on the specific geometric aspects of the environment but can be explained in terms of directional migration toward the tumor, without invoking major feedback components. Overall, our 3D platform allows us to monitor the processes of tumor recruitment, infiltration, and killing by means of live measurements, revealing important kinetic aspects of ACT with CIK and NK against melanoma.

Purpose: The MHC-unrestricted activity of cytokine-induced killer (CIK) cells against chemo-surviving melanoma cancer stem cells (mCSC) was explored, as CSCs are considered responsible for chemoresistance and relapses. Experimental Design: Putative mCSCs were visualized by engineering patient-derived melanoma cells (MC) with a lentiviral vector encoding eGFP under expression control by stemness gene promoter oct4. Their stemness potential was confirmed in vivo by limiting dilution assays. We explored the sensitivity of eGFP+ mCSCs to chemotherapy (CHT), BRAF inhibitor (BRAFi) or CIK cells, as single agents or in sequence, in vitro. First, we treated MCs in vitro with fotemustine or dabrafenib (BRAF-mutated cases); then, surviving MCs, enriched in mCSCs, were challenged with autologous CIK cells. CIK cell activity against chemoresistant mCSCs was confirmed in vivo in two distinct immunodeficient murine models. Results: We visualized eGFP+ mCSCs (14% ± 2.1%) in 11 MCs. The tumorigenic precursor rate in vivo was higher within eGFP+ MCs (1/42) compared with the eGFP− counterpart (1/4,870). In vitro mCSCs were relatively resistant to CHT and BRAFi, but killed by CIK cells (n = 11, 8/11 autologous), with specific lysis ranging from 95% [effector:tumor ratio (E:T), 40:1] to 20% (E:T 1:3). In vivo infusion of autologous CIK cells into mice bearing xenografts from three distinct melanomas demonstrated significant tumor responses involving CHT-spared eGFP+ mCSCs (P = 0.001). Sequential CHT–immunotherapy treatment retained antitumor activity (n = 12, P = 0.001) reducing mCSC rates (P = 0.01). Conclusions: These findings are the first demonstration that immunotherapy with CIK cells is active against autologous mCSCs surviving CHT or BRAFi. An experimental platform for mCSC study and rationale for CIK cells in melanoma clinical study is provided. Clin Cancer Res; 23(9); 2277–88. ©2016 AACR.

Metastatic bone and soft tissue sarcomas often relapse after chemotherapy (CHT) and molecular targeted therapy (mTT), maintaining a severe prognosis. A subset of sarcoma cancer stem cells (sCSC) is hypothesized to resist conventional drugs and sustain disease relapses. We investigated the immunotherapy activity of cytokine induced killer cells (CIK) against autologous sCSC that survived CHT and mTT. The experimental platform included two aggressive bone and soft tissue sarcoma models: osteosarcoma (OS) and undifferentiated-pleomorphic sarcoma (UPS). To visualize putative sCSC we engineered patient-derived sarcoma cultures (2 OS and 3 UPS) with a lentiviral sCSC-detector wherein the promoter of stem-gene Oct4 controls the expression of eGFP. We visualized a fraction of sCSC (mean 24.2 ± 5.2%) and confirmed their tumorigenicity in vivo. sCSC resulted relatively resistant to both CHT and mTT in vitro. Therapeutic doses of doxorubicin significantly enriched viable eGFP+sCSC in both OS (2.6 fold, n = 16) and UPS (2.3 fold, n = 29) compared to untreated controls. Treatment with sorafenib (for OS) and pazopanib (for UPS) also determined enrichment (1.3 fold) of viable eGFP+sCSC, even if less intense than what observed after CHT. Sarcoma cells surviving CHT and mTT were efficiently killed in vitro by autologous CIK even at minimal effector/target ratios (40:1 = 82%, 1:4 = 29%, n = 13). CIK immunotherapy did not spare sCSC that were killed as efficiently as whole sarcoma cell population. The relative chemo-resistance of sCSC and sensitivity to CIK immunotherapy was confirmed in vivo. Our findings support CIK as an innovative, clinically explorable, approach to eradicate chemo-resistant sCSC implicated in tumor relapse.

Cytokine-induced killer (CIK) cells are ex vivo expanded T lymphocytes endowed with potent MHC-independent antitumor activity. CIK cells are emerging as promising therapeutic approach in the field of cancer adoptive immunotherapy, with biologic features favoring their transferability into clinical applications. Aim of this review is to present the biologic characteristic of CIK cells, discussing the main preclinical findings and initial clinical applications in the field of solid tumors.

Conventional treatments reached an unsatisfactory therapeutic plateau in the treatment of advanced unresectable bone and soft tissue sarcomas that remain an unsolved medical need. Several evidences support the concept that adoptive immunotherapy may effectively integrate within the complex and multidisciplinary treatment of sarcomas.In this work we reviewed adoptive immunotherapy strategies that have been explored in sarcoma settings, with specific focus on issues related to their clinic transferability. We schematically divided approaches based on T lymphocytes specific for MHC-restricted tumor-associated antigens or relying on MHC-independent immune effectors such as natural killer (NK), cytokine-induced killer (CIK) or γδ T cells.Preclinical findings and initial clinical reports showed the potentialities and drawbacks of different adoptive immunotherapy strategies. The expansion of tumor infiltrating lymphocytes is difficult to be reproduced outside melanoma. Genetically redirected T cells appear to be a promising option and initial reports are encouraging against patients with sarcomas. Adoptive immunotherapy with MHC-unrestricted effectors such as NK, CIK or γδ T cells has recently shown great preclinical potential in sarcoma setting and biologic features that may favor clinical transferability. Combination of different immunotherapy approaches and integration with conventional treatments appear to be key issues for successful designing of next clinical trials.

Background Antibodies blocking the inhibitory checkpoint PD1, expressed by T lymphocytes, and kinase inhibitors of BRAF and MEK (MAPKi) are mainstays of current treatment for patients with metastatic melanoma. Mouse models point towards a synergistic antitumor activity of anti-PD1-antibodies and MAPKi, explaining the findings by an enhanced lymphocytic activity opposing tumor adaptive resistance. Recently PD1 was found expressed by a subpopulation of melanoma cells where it could mediate tumorigenic effects, but no data exist showing how MAPKi could modulate its expression. We hypothesized that MAPKi may upregulate PD1 expression and enhance the direct, immune-cell independent antitumor action of anti-PD1 antibodies. We first explore the exact prevalence and magnitude of PD1 expression in patients and cell lines. Then we test the effect of MAPKi on its expression and explore possible immune-independent synergisms with anti-PD1-antibodies. Methodology and results. Prevalence of PD1 expression by melanoma cells was explored in the Cancer Cell Line Encyclopedia (CCLE) and The Cancer Genome Atlas (TCGA) datasets. CCLE included 61 melanoma cell lines, which all expressed PD1 (Affymetrix mRNA 4.20 [3.81- 4.65]) with values comparable to PDL1 (4.63, range 3.73 -7.84) and PDL2 (3.73, range 3.97-8.50). The TCGA analysis included 114 melanomas, excluding those with evidence of immune infiltrate (n=256) or stromal cells (n=100) potentially interfering with PD1 assessment. PD1 mRNA was expressed by all samples (median FPKM values: 64.7, range 0.4-1461.3). Next we assessed by flow-cytometry the membrane expression of PD1 in 4 melanoma cell lines and 3 patient-derived melanoma cultures, harboring BRAF and NRAS mutations We confirmed that low rates of PD1 were expressed by all melanoma (median 1.2%, range 0.7- 4.3). The median rate of viable PD1+ melanoma cells significantly increased (12.9% range 5.9-20, p=0.0180, n =7) following treatment (96h) with MAPKi (dabrafenib and trametinib) but not with chemotherapy (fotemustine). Longer treatments (8 days) further increased the rate of PD1+ melanoma cells (31.8% range 15.0-50.3, n=3) and the effect was reversed by drug withdrawal. The MAPKi modulatory effect on PD1 expression was therapeutically exploited in vitro. The addition of PD1 blocking antibody enhanced the inhibitory activity of MAPKi on melanoma proliferation (mean inhibition rate: 66% vs 40%, n=2) in the absence of any immune cells. Conclusions We report a new expression pattern of PD1 receptor on melanoma and its potential therapeutic perspective. PD1 is directly expressed by a small but consistent rate of melanoma cells. Treatment with MAPKi significantly enhanced the rate of PD1+ melanoma cells and direct synergism with PD1 blockade was reported without the involvement of immune response. Our findings may be clinical relevant in settings of patients treated with MAPKi. Citation Format: Martina Sanlorenzo, Igor Vujic, Arianna Floris, Mauro Novelli, Chiara Donini, Loretta Gammaitoni, Lidia Giraudo, Marco Macagno, Pietro Quaglino, Maria Teresa Fierro, Silvia Giordano, Fabrizio Carnevale-Schianca, Massimo Aglietta, Dario Sangiolo. Melanoma PD1 expression is upregulated by MAPK inhibitors leading to an immune-independent synergism with anti-PD1 antibodies [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 5603. doi:10.1158/1538-7445.AM2017-5603

Allogeneic hematopoietic cell transplant (HCT) remains the only curative therapy for many hematologic malignancies but it is limited by high nonrelapse mortality (NRM), primarily from unpredictable control of graft-versus-host disease (GVHD). Recently, post-transplant cyclophosphamide demonstrated improved GVHD control in allogeneic bone marrow HCT. Here we explore cyclophosphamide in allogeneic peripheral blood stem cell transplantation (alloPBSCT). Patients with high-risk hematologic malignancies received alloPBSCT from HLA-matched unrelated/related donors. GVHD prophylaxis included combination post-HCT cyclophosphamide 50 mg/kg (days +3 and +4) and tacrolimus/mofetil mycophenolate (T/MMF) (day +5 forward). The primary objective was the cumulative incidence of acute and chronic GVHD. Between March 2011 and May 2015, 35 consecutive patients received the proposed regimen. MMF was stopped in all patients at day +28; the median discontinuation of tacrolimus was day +113. Acute and chronic GVHD cumulative incidences were 17% and 7%, respectively, with no grade IV GVHD events, only 2 patients requiring chronic GVHD immunosuppression control, and no deaths from GVHD. Two-year NRM, overall survival, event-free survival, and chronic GVHD event-free survival rates were 3%, 77%, 54%, and 49%, respectively. The graft-versus-tumor effect was maintained as 5 of 15 patients (33%) who received HCT with evidence of disease experienced further disease response. A post-transplant cyclophosphamide + T/MMF combination strategy effectively prevented acute and chronic GVHD after alloPBSCT from HLA-matched donors and achieved an unprecedented low NRM without losing efficacy in disease control or impaired development of the graft-versus-tumor effect. This trial is registered at clinicaltrials.gov as NCT02300571.

Unresectable metastatic bone sarcoma and soft-tissue sarcomas (STS) are incurable due to the inability to eradicate chemoresistant cancer stem–like cells (sCSC) that are likely responsible for relapses and drug resistance. In this study, we investigated the preclinical activity of patient-derived cytokine-induced killer (CIK) cells against autologous bone sarcoma and STS, including against putative sCSCs. Tumor killing was evaluated both in vitro and within an immunodeficient mouse model of autologous sarcoma. To identify putative sCSCs, autologous bone sarcoma and STS cells were engineered with a CSC detector vector encoding eGFP under the control of the human promoter for OCT4, a stem cell gene activated in putative sCSCs. Using CIK cells expanded from 21 patients, we found that CIK cells efficiently killed allogeneic and autologous sarcoma cells in vitro. Intravenous infusion of CIK cells delayed autologous tumor growth in immunodeficient mice. Further in vivo analyses established that CIK cells could infiltrate tumors and that tumor growth inhibition occurred without an enrichment of sCSCs relative to control-treated animals. These results provide preclinical proof-of-concept for an effective strategy to attack autologous sarcomas, including putative sCSCs, supporting the clinical development of CIK cells as a novel class of immunotherapy for use in settings of untreatable metastatic disease. Cancer Res; 74(1); 119–29. ©2013 AACR.

Purpose: The goals of this study are i) to analyze the expression of human leukocyte antigen class I (HLA-I) antigen processing machinery (APM) components in surgically removed melanoma tumors, ii) to assess their modulation by Interferons (IFNs) and iii) to determine their value as predictive biomarkers of the clinical response to immunotherapy with checkpoint inhibitors (CI). Methods: The expression levels of HLA class I APM components [HLA-I (ABC) chains, beta(2)microglobulin (β2m), Calnexin, Calreticulin, ERp57, Tapasin, TAP1-2, LMP2, LMP7, LMP10] were evaluated by staining with mAbs and flow cytometry in melanoma cells isolated from surgical biopsies from 16 patients with advanced melanoma. In addition the modulation of these molecules by IFN-γ or IFN-α2 (IFNs) was evaluated. Results: The frequency of cells expressing HLA-I/β2m was >90% in 15/16 Mel tumors. In 1 case extracellular HLA-I/β2m molecules were not detected. The expression levels of extracellular HLA class I APM molecules were quite heterogeneous. Based on Mean Fluorescence Intensity (MFI) of HLA-I/β2m, Mel segregated into 2 groups with high (MFI >200, n=8) and low (MFI Conclusions: We report a wide heterogeneous distribution of HLA-I/β2m expression levels and deficits of APM components in Melanoma, partially restorable by IFNs. Our data support the possibility that defects in HLA expression, not responsive to IFN restoration, may predict low responsiveness to CI. We provide rationale to incorporate the evaluation of HLA-I/β2m and APM in clinical immunotherapy studies with CI. Citation Format: Lidia Giraudo, Loretta Gammaitoni, Bortolot Valentina, Ilenia Iaia, Giulia Cattaneo, Paolo Becco, Susanna Gallo, Alessandro Zaccagna, Alberto Pisacane, Luca Crotto, Soldano Ferrone, Massimo Aglietta, Fabrizio Carnevale Schianca, Dario Sangiolo. Expression and modulation by IFN of HLA class I APM components in melanoma: Potential biomarkers of clinical response to checkpoint inhibitors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 569.

Purpose: We investigate the unknown tumor-killing activity of cytokine-induced killer (CIK) cells against autologous metastatic melanoma and the elusive subset of putative cancer stem cells (mCSC). Experimental Design: We developed a preclinical autologous model using same patient-generated CIK cells and tumor targets to consider the unique biology of each patient/tumor pairing. In primary tumor cell cultures, we visualized and immunophenotypically defined a putative mCSC subset using a novel gene transfer strategy that exploited their exclusive ability to activate the promoter of stemness gene Oct4. Results: The CIK cells from 10 patients with metastatic melanoma were successfully expanded (median, 23-fold; range, 11–117). Primary tumor cell cultures established and characterized from the same patients were used as autologous targets. Patient-derived CIK cells efficiently killed autologous metastatic melanoma [up to 71% specific killing (n = 26)]. CIK cells were active in vivo against autologous melanoma, resulting in delayed tumor growth, increased necrotic areas, and lymphocyte infiltration at tumor sites. The metastatic melanoma cultures presented an average of 11.5% ± 2.5% putative mCSCs, which was assessed by Oct4 promoter activity and stemness marker expression (Oct4, ABCG2, ALDH, MITF). Expression was confirmed on mCSC target molecules recognized by CIK cells (MIC A/B; ULBPs). CIK tumor killing activity against mCSCs was intense (up to 71%, n = 4) and comparable with results reported against differentiated metastatic melanoma cells (P = 0.8). Conclusions: For the first time, the intense killing activity of CIK cells against autologous metastatic melanoma, including mCSCs, has been shown. These findings move clinical investigation of a new immunotherapy for metastatic melanoma, including mCSCs, closer. Clin Cancer Res; 19(16); 4347–58. ©2013 AACR.

Background Angiogenesis inhibition is a promising approach for treating metastatic colorectal cancer (mCRC). Recent evidences support the seemingly counterintuitive ability of certain antiangiogenic drugs to promote normalization of residual tumor vessels with important clinical implications. Lenalidomide is an oral drug with immune-modulatory and anti-angiogenic activity against selected hematologic malignancies but as yet little is known regarding its effectiveness for solid tumors. The aim of this study was to determine whether lenalidomide can normalize colorectal cancer neo-vessels in vivo, thus reducing tumor hypoxia and improving the benefit of chemotherapy. Methods We set up a tumorgraft model with NOD/SCID mice implanted with a patient-derived colorectal cancer liver metastasis. The mice were treated with oral lenalidomide (50 mg/Kg/day for 28 days), intraperitoneal 5-fluorouracil (5FU) (20 mg/Kg twice weekly for 3 weeks), combination (combo) of lenalidomide and 5FU or irrelevant vehicle. We assessed tumor vessel density (CD146), pericyte coverage (NG2; alphaSMA), in vivo perfusion capability of residual vessels (lectin distribution essay), hypoxic areas (HP2-100 Hypoxyprobe) and antitumor activity in vivo and in vitro. Results Treatment with lenalidomide reduced tumor vessel density (p = 0.0001) and enhanced mature pericyte coverage of residual vessels (p = 0.002). Perfusion capability of tumor vessels was enhanced in mice treated with lenalidomide compared to controls (p = 0.004). Accordingly, lenalidomide reduced hypoxic tumor areas (p = 0.002) and enhanced the antitumor activity of 5FU in vivo. The combo treatment delayed tumor growth (p = 0.01) and significantly reduced the Ki67 index (p = 0.0002). Lenalidomide alone did not demonstrate antitumor activity compared to untreated controls in vivo or against 4 different mCRC cell lines in vitro. Conclusions We provide the first evidence of tumor vessel normalization and hypoxia reduction induced by lenalidomide in mCRC in vivo. This effect, seemingly counterintuitive for an antiangiogenic compound, translates into indirect antitumor activity thus enhancing the therapeutic index of chemotherapy. Our findings suggest that further research should be carried out on synergism between lenalidomide and conventional therapies for treating solid tumors that might benefit from tumor vasculature normalization.

Conventional chemotherapies seemed to have reached a therapeutic plateau in the treatment of solid tumors and many metastatic diseases are still incurable. Events of chemo-resistance and relapses appear to be sustained by a subset of putative cancer stem cells (CSCs). New anticancer strategies need to face this new challenge exploring their efficacy against CSCs. Immunotherapy has raised enthusiasms in cancer therapy and its potential against CSCs is an intriguing field of research.In this work we reviewed the immunotherapy approaches directed against CSCs in solid tumors. We schematically divided adaptive immunotherapy strategies, mainly based on dendritic cell-vaccination, and strategies exploiting MHC-unrestricted effectors like natural killer cells, γδ T lymphocytes and cytokine-induced killer cells. Findings, strength and limitations of these models are discussed and compared highlighting their potential clinical relevance.The important biologic role and clinical relevance of CSCs introduced a 'noble target' for immunotherapy and cancer treatments in general. Initial evidences suggest that CSCs may be susceptible to various types of immunotherapy attacks, overcoming their chemo-resistance. Investigation of important safety issues, based on shared features with 'normal' stem cells, along with intriguing synergisms with modulatory agents are open challenges for the next future and effective clinical translation.

Adoptive immunotherapy is considered a promising strategy for the treatment of metastatic tumors and current research efforts are directed to define the optimal approach and facilitate the transferability from preclinical to clinical settings. Among several approaches it is possible to schematically distinguish strategies based on either MHC-restricted or MHC-unrestricted immune effectors. The first are mainly based on the infusion of tumor-specific T lymphocytes capable of recognizing determined MHC-restricted tumor associated antigens (TAA) through their T cell receptor. MHC-unrestricted approaches do not target specific tumor associated antigens and are mainly mediated by effectors of the innate immune system, like natural killer (NK) cells or NKT cells, first barrier against pathogens and tumorigenesis processes, or by ex vivo activated lymphocytes like cytokine-induced killer (CIK) cells. MHC-unrestricted effectors are usually more abundant than TAA-specific precursors and easier to expand. Furthermore their activity is not restricted to precise HLAhaplotypes, not limited to a single tumor histotype and could overcome downregulation of MHC molecules operated by tumor cells as immune escape mechanism. In this review we will discuss the main cancer immunotherapy strategies based on MHC-unrestricted immune effectors. The topic will be approached from the angle of ex vivo expansion protocols in clinical prospective, as well as potential approaches to favorably modulate their functions.