Synthetic receptor signalling has the potential to endow adoptively transferred T cells with new functions that overcome major barriers in the treatment of solid tumours, including the need for ...conditioning chemotherapy
. Here we designed chimeric receptors that have an orthogonal IL-2 receptor extracellular domain (ECD) fused with the intracellular domain (ICD) of receptors for common γ-chain (γ
) cytokines IL-4, IL-7, IL-9 and IL-21 such that the orthogonal IL-2 cytokine elicits the corresponding γ
cytokine signal. Of these, T cells that signal through the chimeric orthogonal IL-2Rβ-ECD-IL-9R-ICD (o9R) are distinguished by the concomitant activation of STAT1, STAT3 and STAT5 and assume characteristics of stem cell memory and effector T cells. Compared to o2R T cells, o9R T cells have superior anti-tumour efficacy in two recalcitrant syngeneic mouse solid tumour models of melanoma and pancreatic cancer and are effective even in the absence of conditioning lymphodepletion. Therefore, by repurposing IL-9R signalling using a chimeric orthogonal cytokine receptor, T cells gain new functions, and this results in improved anti-tumour activity for hard-to-treat solid tumours.
The effects on cell signalling networks upon blockade of cytotoxic T lymphocyte-associated antigen-4 (CTLA4) using the monoclonal antibody tremelimumab were studied in peripheral blood mononuclear ...cell (PBMC) samples from patients with metastatic melanoma.
Findings Intracellular flow cytometry was used to detect phosphorylated (p) signaling molecules downstream of the T cell receptor (TCR) and cytokine receptors. PBMC from tremelimumab-treated patients were characterized by increase in pp38, pSTAT1 and pSTAT3, and decrease in pLck, pERK1/2 and pSTAT5 levels. These changes were noted in CD4 and CD8 T lymphocytes but also in CD14 monocytes. A divergent pattern of phosphorylation of Zap70, LAT, Akt and STAT6 was noted in patients with or without an objective tumor response.
The administration of the CTLA4-blocking antibody tremelimumab to patients with metastatic melanoma influences signaling networks downstream of the TCR and cytokine receptors both in T cells and monocytes. The strong modulation of signaling networks in monocytes suggests that this cell subset may be involved in clinical responses to CTLA4 blockade.
clinicaltrials.gov; Registration numbers NCT00090896 and NCT00471887.
Expression of viral proteins frequently includes non-canonical decoding events ('recoding') during translation. '2A' oligopeptides drive one such event, termed 'stop-carry on' recoding. Nascent 2A ...peptides interact with the ribosomal exit tunnel to dictate an unusual stop codon-independent termination of translation at the final Pro codon of 2A. Subsequently, translation 'reinitiates' on the same codon, two individual proteins being generated from one open reading frame. Many 2A peptides have been identified, and they have a conserved C-terminal motif. Little similarity is present in the N-terminal portions of these peptides, which might suggest that these amino acids are not important in the 2A reaction. However, mutagenesis indicates that identity of the amino acid at nearly all positions of a single 2A peptide is important for activity. Each 2A may then represent a specific solution for positioning the conserved C-terminus within the peptidyl-transferase centre to promote recoding. Nascent 2A peptide:ribosome interactions are suggested to alter ribosomal fine structure to discriminate against prolyl-tRNA(Pro) and promote termination in the absence of a stop codon. Such structural modifications may account for our observation that replacement of the final Pro codon of 2A with any stop codon both stalls ribosome processivity and inhibits nascent chain release.
BackgroundIntratumoral immunotherapies are being tested in different solid tumors. They trigger local and systemic responses.1 2 BO-112 is a double stranded RNA nanoplexed with polyethyleneimine ...(PEI), which mimics a viral infection and mobilizes the immune system.In preclinical models and in a first in human clinical trial BO-112 activated dendritic cells, induced CD-8 infiltration, apoptosis and enhancement of immunogenic cell death and achieved an objective response in 2 out of 10 patients with melanoma with primary resistance to antiPD-1.3 4 MethodsIn this phase 2 study, BO-112 plus pembrolizumab is evaluated in patients with advanced melanoma, who have developed progressive disease while on or within 12 weeks after anti-PD1/PD-L1 based therapy (either as first line or as adjuvant treatment). BO-112 is administered intratumorally once weekly in 1 to 8 tumor lesions, total dose 1 to 2 mg, for the first 7 weeks and thereafter every three weeks; pembrolizumab 200 mg is administered intravenously every three weeks. Overall response rate (ORR) is analyzed as primary endpoint by independent reviewer. Secondary objectives include disease control rate (DCR), duration of response and progression free survival (PFS); response assessment is done by RECIST 1.1 and iRECIST; in addition, CD-8 and PD-L1 IHC, NGS, itRECIST and radiomics signatures are prospectively assessed. Key eligibility criteria include cutaneous or mucosal melanoma with known BRAF status; at least one lesion RECIST 1.1 measurable and amenable for IT injection. Enrollment has been completed on 26th August.ResultsWith 26 evaluable patients with a first response assessment, seven have progressive disease (PD), five have partial response (PR) and fourteen patients show stable disease (SD). Preliminary ORR is 19.2% and DCR is 73.1% at week 8. Three patients with PR at week 8 have undergone a second assessment at week 16, with further decrease in sum of diameters (SOD) in both injected and non-injected lesions. Three out of five patients with SD and a second assessment maintain SD, showing a decrease in SOD in two cases (figure 1). In addition, two patients with only skin lesions have a pathological complete response. CD8 and PD-L1 have increased in 8 and 7 out of 13 patients with paired biopsies, being related with clinical benefit (figure 2).Abstract 961 Figure 1Swimmer plot, efficacy data for evaluable patients undergoing at least one response assessmentAbstract 961 Figure 2Immunohistochemistry data for CPS and CD8 data from paired biopsiesConclusionsDespite these data being preliminary, there is a trend for benefit in terms of ORR and also in long lasting stable diseases. BO-112 is able to increase PD-L1 expression in tumor cells and increase CD8-T cell infiltrates.AcknowledgementsMerck, Pivotal SLU, Quibim radiomics, Pangaea laboratories, all participating sites and patientsTrial RegistrationNCT04570332ReferencesAznar MA, Planelles L, Perez-Olivares M, et al. Immunotherapeutic effects of intratumoral nanoplexed poly I:C. J Immunother Cancer. 2019 May 2;7(1):116.5. Hamid O, Ismail R, Puzanov I. Intratumoral immunotherapy-update 2019. The Oncologist 2020;25:e423–438.Márquez-Rodas I, Longo F, Rodríguez-Ruiz M, et al. Intratumoral nanoplexed poly I:C BO-112 in combination with systemic anti-PD-1 for patients with anti-PD-1-refractory tumors. Sci Transl Med 2020 Oct 14;12(565):eabb0391.Kalbasi A, Tariveranmoshabad M, Hakimi K, Kremer S, et al. A. Uncoupling interferon signaling and antigen presentation to overcome immunotherapy resistance due to JAK1 loss in melanoma. Sci Transl Med 2020 Oct 14;12(565):eabb0152.Ethics ApprovalThe study obtained ethics approval by Spanish Health Agency (AEMPS), on 11th December 2020, and French Health Agency (ANSM) on 27th January 2021; study obtained approval from two Ethics Committee: Vall D’Hebron, Barcelona, Spain on 7th December 2020 (number 467), and Centre Léon Bérard, Lyon, France, CPP 20.11.10.38825 on 11th February 2021.For each study patient, written informed consent is obtained prior to any protocol-related activities. As part of this procedure, the principal investigator or one of his/her associates must explain orally and in writing the nature, duration, and purpose of the study, and the action of the study drug in such a manner that the patient is aware of the potential risks, inconveniences, or adverse effects that may occur. They should be informed that the patient may withdraw from the study at any time. They will receive all information that is required by the regulatory authorities and ICH guidelines. The ICF has been signed by the patient and a copy provided to them.ConsentN/A
PLX4032 (RG7204), an oncogenic BRAF kinase inhibitor undergoing clinical evaluation, has high response rates in early clinical trials in patients with advanced BRAF(V600E) mutant melanoma. Combining ...PLX4032 with immunotherapy may allow expanding the durability of responses. The effects of PLX4032 on immune cells were studied to explore the feasibility of future combinatorial approaches with immunotherapy for melanoma.
Peripheral blood mononuclear cells (PBMC) and BRAF(V600E) mutant melanoma cells were exposed to increasing concentrations of PLX4032 and the cell viability, proliferation, cell cycle, apoptosis, and phosphorylation of signaling proteins were analyzed. Effects of PLX4032 on antigen-specific T-cell function were analyzed by specific cytokine release and cytotoxicity activity.
The 50% inhibition concentration (IC(50)) of PLX4032 for resting human PBMC was between 50 and 150 μmol/L compared with an IC(50) below 1 μmol/L for sensitive BRAF(V600E) mutant melanoma cell lines. Activated lymphocytes were even more resistant with no growth inhibition up to concentrations of 250 μmol/L. PLX4032 had a marginal effect on cell-cycle arrest, apoptotic cell changes or alteration of phosphorylated signaling molecules in lymphocytes. Functional analysis of specific antigen recognition showed preserved T-cell function up to 10-μmol/L concentration of PLX4032, whereas the cytotoxic activity of PLX4032 was maintained up to high concentrations of 50 μmol/L.
The preserved viability and function of lymphocytes exposed to high concentrations of PLX4032 suggest that this agent could be a potential candidate for combining with immunotherapy strategies for the treatment of patients with BRAF(V600)(E) mutant melanoma.
Approximately 20% of melanomas contain a mutation in NRAS. However no direct inhibitor of NRAS is available. One of the main signaling pathways downstream of NRAS is the MAPK pathway. In this study ...we investigated the possibility of blocking oncogenic signaling of NRAS by inhibiting two signaling points in the MAPK pathway.
Fourteen NRAS mutated human melanoma cell lines were treated with a pan-RAF inhibitor (PRi, Amgen Compd A), a MEK inhibitor (MEKi, trametinib) or their combination and the effects on proliferation, cell cycle progression, apoptosis, transcription profile and signaling of the cells were investigated.
The majority of the cell lines showed a significant growth inhibition, with high levels of synergism of the PRi and MEKi combination. Sensitive cell lines showed induction of apoptosis by the combination treatment and there was a correlation between p-MEK levels and synergistic effect of the combination treatment. Proliferation of sensitive cell lines was blocked by the inhibition of the MAPK pathway, which also blocked expression of cyclin D1. However, in resistant cell lines, proliferation was blocked by combined inhibition of the MAPK pathway and cyclin D3, which is not regulated by the MAPK pathway. Resistant cell lines also showed higher levels of p-GSK3β and less perturbation of the apoptotic profile upon the treatment in comparison with the sensitive cell lines.
The combination of PRi + MEKi can be an effective regimen for blocking proliferation of NRAS mutant melanomas when there is higher activity of the MAPK pathway and dependence of proliferation and survival on this pathway.
Radioimmunotherapy combines irradiation of tumor lesions with immunotherapy to achieve local and abscopal control of cancer. Most immunotherapy agents are given systemically, but strategies for ...delivering immunotherapy locally are under clinical scrutiny to maximize efficacy and avoid toxicity. Local immunotherapy, by injecting various pathogen-associated molecular patterns, has shown efficacy both preclinically and clinically. BO-112 is a viral mimetic based on nanoplexed double-stranded RNA (poly I:C) which exerts immune-mediated antitumor effects in mice and humans on intratumoral delivery. BO-112 and focal irradiation were used to make the proof-of-concept for local immunotherapy plus radiation therapy combinations.
Murine transplantable tumor cell lines (TS/A, MC38 and B16-OVA) were used to show increased immunogenic features under irradiation, as well as in bilateral tumor models in which only one of the lesions was irradiated or/and injected with BO-112. Flow cytometry and multiplex tissue immunofluorescence were used to determine the effects on antitumor immunity. Depletions of immune cell populations and knockout mice for the IFNAR and BATF-3 genes were used to delineate the immune system requirements for efficacy.
In cultures of TS/A breast cancer cells, the combination of irradiation and BO-112 showed more prominent features of immunogenic tumor cell death in terms of calreticulin exposure. Injection of BO-112 into the tumor lesion receiving radiation achieved excellent control of the treated tumor and modest delays in contralateral tumor progression. Local effects were associated with more prominent infiltrates of antitumor cytotoxic tumor lymphocytes (CTLs). Importantly, local irradiation plus BO-112 in one of the tumor lesions that enhanced the therapeutic effects of radiotherapy on distant irradiated lesions that were not injected with BO-112. Hence, this beneficial effect of local irradiation plus BO-112 on a tumor lesion enhanced the therapeutic response to radiotherapy on distant non-injected lesions.
This study demonstrates that local BO-112 immunotherapy and focal irradiation may act in synergy to achieve local tumor control. Irradiation plus BO-112 in one of the tumor lesions enhanced the therapeutic effects on distant irradiated lesions that were not injected with BO-112, suggesting strategies to treat oligometastatic patients with lesions susceptible to radiotherapy and with at least one tumor accessible for repeated BO-112 intratumoral injections.
Adoptive cell therapy (ACT) consisting of genetically engineered T cells expressing tumor antigen-specific T-cell receptors displays robust initial antitumor activity, followed by loss of T-cell ...activity/persistence and frequent disease relapse. We characterized baseline and longitudinal T-cell phenotype variations resulting from different manufacturing and administration protocols in patients who received ACT. Patients with melanoma who enrolled in the F5-MART-1 clinical trial (NCT00910650) received infusions of MART-1 T-cell receptors transgenic T cells with MART-1 peptide-pulsed dendritic cell vaccination. Patients were divided into cohorts based on several manufacturing changes in the generation and administration of the transgenic T cells: decreasing ex vivo stimulation/expansion time, increased cell dose, and receiving fresh instead of cryopreserved cells. T-cell phenotypes were analyzed by flow cytometry at baseline and longitudinally in peripheral blood. Transgenic T cells with shorter ex vivo culture/expansion periods displayed significantly increased expression of markers associated with less differentiated naive/memory populations, as well as significantly decreased expression of the inhibitory receptor programmed death 1 (PD1). Patients receiving fresh infusions of transgenic cells demonstrated expansion of central memory T cells and delayed acquisition of PD1 expression compared with patients who received cryopreserved products. Freshly infused transgenic T cells showed persistence and expansion of naive and memory T-cell populations and delayed acquisition of PD1 expression, which correlated with this cohort's superior persistence of transgenic cells and response to dendritic cell vaccines. These results may be useful in designing future ACT protocols.
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