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Whole-exome sequencing was performed on four patients' tumors before exposure to pembrolizumab and after disease progression following a response to treatment. Acquired mutations involving antigen presentation and interferon response were noted. Durable responses in metastatic cancers have been achieved with a variety of immunotherapies such as interleukin-2, adoptive cell transfer of tumor-infiltrating lymphocytes, antibodies that block cytotoxic T-lymphocyte–associated antigen 4 (CTLA4), 1 – 5 and antibodies that block programmed death 1 (PD-1). 6 – 10 However, in a recent study, approximately 25% of patients with melanoma who had had an objective response to PD-1 blockade therapy had disease progression at a median follow-up of 21 months. 11 The mechanisms of immune-resistant cancer progression are mostly unknown. Previous studies involving humans examined the loss of beta-2-microglobulin as a mechanism of acquired resistance to several forms of cancer . . .

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 1 , 2 . 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 c ) cytokines IL-4, IL-7, IL-9 and IL-21 such that the orthogonal IL-2 cytokine elicits the corresponding γ c 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. Synthetic chimeric orthogonal IL-2 receptors that incorporate the intracellular domain of receptors for other γ-chain cytokines such as IL-9 can reroute orthogonal signalling and alter the phenotype of T cells to improve anti-tumour responses.

The immune checkpoint therapy is a relatively recent strategy that aims to tweak the immune system to effectively attack cancer cells. The understanding of the immune responses and their regulation at the intracellular level and the development of fully humanized monoclonal antibodies are the pillars of an approach that could elicit durable clinical responses and even remission in some patients with cancer. Most of the immune checkpoints that regulate the T-cell responses (activation and inhibition) operate through proteins present on the cytoplasmic membrane of the immune cells. Therefore, specific antibodies capable of blocking the inhibitory signals should lead to unrestrained immune responses that supersede the inhibitory mechanisms, which are naturally present in the tumor microenviroment. The best-known and most successful targets for immune checkpoint therapy are the cytotoxic T-lymphocyte antigen-4 and programmed cell death-1 coreceptors. Tremelimumab (CP-675,206) is a fully humanized monoclonal antibody specific for cytotoxic T-lymphocyte antigen-4, which has been successfully used to treat patients with metastatic melanoma and some other cancers. Although still a work in progress, the use of tremelimumab as an immune checkpoint therapeutic agent is a promising approach alone or in combination with other anticancer drugs. Here, we review the use of this antibody in a number of clinical trials against solid tumors.

Wound healing is a multi-step process to rapidly restore the barrier function. This process is often impaired in diabetic patients resulting in chronic wounds and amputation. We previously found that paradoxical activation of the mitogen-activated protein kinase (MAPK) pathway via topical administration of the BRAF inhibitor vemurafenib accelerates wound healing by activating keratinocyte proliferation and reepithelialization pathways in healthy mice. Herein, we investigated whether this wound healing acceleration also occurs in impaired diabetic wounds and found that topical vemurafenib not only improves wound healing in a murine diabetic wound model but unexpectedly promotes hair follicle regeneration. Hair follicles expressing Sox-9 and K15 surrounded by CD34+ stroma were found in wounds of diabetic and non-diabetic mice, and their formation can be prevented by blocking downstream MEK signaling. Thus, topically applied BRAF inhibitors may accelerate wound healing, and promote the restoration of improved skin architecture in both normal and impaired wounds.

BRAF inhibitors are highly effective therapies for the treatment of BRAF V600 -mutated melanoma, with the main toxicity being a variety of hyperproliferative skin conditions due to paradoxical activation of the mitogen-activated protein kinase (MAPK) pathway in BRAF wild-type cells. Most of these hyperproliferative skin changes improve when a MEK inhibitor is co-administered, as it blocks paradoxical MAPK activation. Here we show how the BRAF inhibitor vemurafenib accelerates skin wound healing by inducing the proliferation and migration of human keratinocytes through extracellular signal-regulated kinase (ERK) phosphorylation and cell cycle progression. Topical treatment with vemurafenib in two wound-healing mice models accelerates cutaneous wound healing through paradoxical MAPK activation; addition of a mitogen-activated protein kinase kinase (MEK) inhibitor reverses the benefit of vemurafenib-accelerated wound healing. The same dosing regimen of topical BRAF inhibitor does not increase the incidence of cutaneous squamous cell carcinomas in mice. Therefore, topical BRAF inhibitors may have clinical applications in accelerating the healing of skin wounds. BRAF inhibitors often show skin-hyperproliferative side effects in melanoma patients. Here, the authors demonstrate that BRAF inhibitors can be used to enhance skin wound healing through the MAPK- ERK pathway activation that positively regulates the proliferation of keratinocytes.

BackgroundRadioimmunotherapy 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.MethodsMurine 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.ResultsIn 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.ConclusionThis 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.

Keratoacanthomas (KAs) and cutaneous squamous cell carcinomas (cuSCCs) develop in 15–30% of patients with BRAFV600E metastatic melanoma treated with BRAF inhibitors (BRAFi). These lesions resemble mouse skin tumors induced by the two-stage DMBA/TPA skin carcinogenesis protocol; in this protocol BRAFi accelerates tumor induction. Since prior studies demonstrated cyclooxygenase 2 (COX-2) is necessary for DMBA/TPA tumor induction, we hypothesized that COX-2 inhibition might prevent BRAFi-accelerated skin tumors. Celecoxib, a COX-2 inhibitor, significantly delayed tumor acceleration by the BRAFi inhibitor PLX7420 and decreased tumor number by 90%. Tumor gene expression profiling demonstrated that celecoxib partially reversed the PLX4720-induced gene signature. In PDV cuSCC cells, vemurafenib (a clinically approved BRAFi) increased ERK phosphorylation and soft agar colony formation; both responses were greatly decreased by celecoxib. In clinical trials trametinib, a MEK inhibitor (MEKi) increases BRAFi therapy efficacy in BRAFV600E melanomas and reduces BRAFi-induced KA and cuSCC frequency. Trametinib also reduced vemurafenib-induced PDV soft agar colonies, but less efficiently than celecoxib. The trametinb/celecoxib combination was more effective than either inhibitor alone. In conclusion, celecoxib suppressed both BRAFi-accelerated skin tumors and soft-agar colonies, warranting its testing as a chemopreventive agent for non-melanoma skin lesions in patients treated with BRAFi alone or in combination with MEKi. •Celecoxib delays squamous cell carcinoma (SCC) tumor acceleration by PLX7420.•It also decreases SCC tumor number by 90%.•It partially reversed the PLX4720-induced gene signature.•Trametinb/celecoxib combination is more effective than either inhibitor alone.

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.

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