Checkpoint Blockade for the Treatment of Advanced Melanoma

Signatures of immune cell infiltration for predicting immune escape and immunotherapy in cervical cancer

The cervical cancer tumor microenvironment is a diverse and complex ecosystem. Tumor-immune cell infiltration (ICI) may influence immune escape and immunotherapeutic responses. However, the relationship between immune cell infiltrations, immune escape, and immunotherapy in cervical cancer has not been fully clarified. Here, Principal component analysis (PCA) and Tumor immune dysfunction and exclusion (TIDE) were applied to calculate individual ICI scores and probabilities of immune escape, respectively. Through the IMvigor210 and the Cancer Immunome Atlas (TCIA) datasets, we validated the different responses to immunotherapy in two subgroups of patients. Furthermore, therapeutic benefits of different patients were predicted by the pRRophetic package. We found that patients with high ICI scores were prone to immune escape due to the activated JAK-STAT signaling pathway, along with lower CD8+ T cells. High ICI scores patients could benefit more from anti-PD-L1 immunotherapy, and individuals with low scores may be better candidates for the anti-CTLA-4 treatment. Combinations of immunotherapies with targeted inhibitors may improve clinical efficacy and reduce the risk of tumor recurrence. The ICI model not only helps us enhance the cognition of immune escape, but also guides the application of immunotherapy in cervical cancer patients.

Construction of an immune-related ceRNA network in cervical cancer based on HPV E6 splicing

Background

Cervical cancer is one of the leading causes of cancer-related deaths worldwide. The unspliced human papillomavirus (HPV) E6 plays an important role in tumor progression and immune regulation. Improved immunotherapy implementation might benefit from a better knowledge of HPV E6 splicing-related immune gene expressions and immunocyte infiltration in cervical cancer. This study aimed to identify the potential therapeutic and prognostic roles of unspliced/spliced E6 ratio (E6 ratio) in cervical cancer.

Methods

Data from the TCGA were used to analyze the E6 condition and clinical information. Nomogram and K-M analysis were used to analyze assess the prognostic significance, IOBR was used to investigate immunological infiltrates. Functions and pathway enrichment analysis of DEGs were investigated through GO analysis and KEGG pathway analysis, respectively. A core module was taken from the competitive endogenous RNA (ceRNA) network and used to build a lncRNA-miRNA-mRNA network. QT-qPCR was used to detect the expression of genes. CCK-8, colony formation, wound healing and migration assays were used to detect cell functions.

Results

Our study found that HPV E6 ratio had significantly correlation with overall survival. In cervical cancer, a high E6 ratio was adversely linked with infiltrating levels of aDC, M1 macrophages, monocytes, NKT, and Tgd. High E6 ratio phenotypes were shown to be implicated in immune response regulation, cell adhesion, and Wnt signaling pathways, according to functional enrichment analysis. Subsequently, we constructed an immune-related ceRNA network based on E6 splicing in cervical cancer, including three lncRNA (LINC00943, LIFR-AS1, DANT2, and RASSF8-AS1), four miRNA (miR-205-5p, miR-181d-5p, miR-222-3p, and miR-221-3p), and seven mRNA (FGFR1, PRLR, CXCL2, ISG20, ISG15, SDC1, and NR2F2). Among them, CXCL2, SDC1, and miR-221-3p were associated with survival and immune cell infiltration.

Conclusions

These data imply that a high E6 ratio in cervical cancer contributes to the immune-related ceRNA network, resulting in a low amount of infiltrating effector immune cells and tumor growth. As a result, the E6 ratio might be employed as a biomarker in cervical cancer to determine prognosis and treatment success.

Advances in Pancreatic Ductal Adenocarcinoma Treatment

Pancreatic Ductal Adenocarcinoma (PDAC) is one of the deadliest malignancies among all cancers. Despite curative intent, surgery and the use of standard cytotoxic chemotherapy and radiation therapy, PDAC remains treatment-resistant. In recent years, more contemporary treatment modalities such as immunotherapy via checkpoint inhibition have shown some promise in many other malignancies, yet PDAC still eludes an effective curative treatment. In investigating these phenomena, research has suggested that the significant desmoplastic and adaptive tumor microenvironment (TME) of PDAC promote the proliferation of immunosuppressive cells and act as major obstacles to treatment efficacy. In this review, we explore challenges associated with the treatment of PDAC, including its unique immunosuppressive TME. This review examines the role of surgery in PDAC, recent advances in surgical approaches and surgical optimization. We further focus on advances in immunotherapeutic approaches, including checkpoint inhibition, CD40 agonists, and discuss promising immune-based future strategies, such as therapeutic neoantigen cancer vaccines as means of overcoming the resistance mechanisms which underly the dense stroma and immune milieu of PDAC. We also explore unique signaling, TME and stromal targeting via novel small molecule inhibitors, which target KRAS, FAK, CCR2/CCR5, CXCR4, PARP and cancer-associated fibroblasts. This review also explores the most promising strategy for advancement in treatment of pancreatic cancer by reviewing contemporary combinatorial approaches in efforts to overcome the treatment refractory nature of PDAC.

Treatment of Advanced Metastatic Melanoma

The introduction in clinical practice of new drug compounds both targeted therapies anti-BRAF and checkpoint inhibitors have largely improved our potential to manage advanced metastatic melanoma patients. This has led to a significant improvement in terms of response rates and particularly in the overall survival (OS). The long-term results of trials with follow-up data of patients treated with targeted or immunotherapies reported median OS rates around 24 months, with 5-year survival rates around 35-40%. As to the drugs currently available and reimbursed by the Italian National Health System, 3 combinations of anti-BRAF/anti-MEK inhibitors are available (dabrafenib/trametinib, vemurafenib/cobimetinib and the most recently introduced encorafenib/binimetinib). As for checkpoint inhibitors, first line immunotherapy is represented by anti-PD1 blockers (nivolumab and pembrolizumab), whilst the anti-CTLA-4 ipilimumab can be used as second line immunotherapy. The decision-making factors that define the best treatment approach in stage IV patients with metastatic melanoma include the mutation pattern, performance status, high/low tumor load, brain metastases, progression pattern (low/fast), and availability of clinical trials. This review will analyze the current therapeutic tools adopted for the treatment of metastatic melanoma patients. It will then focus on the latest results obtained by novel treatments (checkpoint inhibitors and targeted therapies) which can be used in the clinical daily practice.

Prognostic Value of ctDNA Mutation in Melanoma: A Meta-Analysis

PURPOSE

Melanoma is the most aggressive form of skin cancer. Circulating tumor DNA (ctDNA) is a diagnostic and prognostic marker of melanoma. However, whether ctDNA mutations can independently predict survival remains controversial. This meta-analysis assessed the prognostic value of the presence or change in ctDNA mutations in melanoma patients.

METHODS

We identified studies from the PubMed, EMBASE, Web of Science, and Cochrane databases. We estimated the combined hazard ratios (HRs) for overall survival (OS) and progression-free survival (PFS) using either fixed-effect or random-effect models based on heterogeneity.

RESULTS

Sixteen studies including 1,781 patients were included. Both baseline and posttreatment detectable ctDNA were associated with poor OS (baseline detectable vs. undetectable, pooled HR = 1.97, 95% CI = 1.64-2.36, P < 0.00001; baseline undetectable vs. detectable, pooled HR = 0.19, 95% CI = 0.11-0.36, P < 0.00001; posttreatment detectable vs. undetectable, pooled HR = 2.36, 95% CI = 1.30-4.28, P=0.005). For PFS, baseline detectable ctDNA may be associated with adverse PFS (baseline detectable vs. undetectable, pooled HR = 1.41, 95% CI = 0.84-2.37, P=0.19; baseline undetectable vs. detectable, pooled HR = 0.43, 95% CI = 0.19-0.95, P=0.04) and baseline high ctDNA and increased ctDNA were significantly associated with adverse PFS (baseline high vs. low/undetectable, pooled HR = 3.29, 95% CI = 1.73-6.25, P=0.0003; increase vs. decrease, pooled HR = 4.48, 95% CI = 2.45-8.17, P < 0.00001). The baseline BRAFV600 ctDNA mutation-positive group was significantly associated with adverse OS compared with the baseline ctDNA-negative group (pooled HR = 1.90, 95% CI = 1.58-2.29, P < 0.00001). There were no significant differences in PFS between the baseline BRAFV600 ctDNA mutation-detectable group and the undetectable group (pooled HR = 1.02, 95% CI = 0.72-1.44, P=0.92).

CONCLUSION

The presence or elevation of ctDNA mutation or BRAFV600 ctDNA mutation was significantly associated with worse prognosis in melanoma patients.

Cervical Cancer Immunotherapy: Facts and Hopes

It is a sad fact that despite being almost completely preventable through human papillomavirus (HPV) vaccination and screening, cervical cancer remains the fourth most common cancer to affect women worldwide. Persistent high-risk HPV (hrHPV) infection is the primary etiologic factor for cervical cancer. Upward of 70% of cases are driven by HPV types 16 and 18, with a dozen other hrHPVs associated with the remainder of cases. Current standard-of-care treatments include radiotherapy, chemotherapy, and/or surgical resection. However, they have significant side effects and limited efficacy against advanced disease. There are a few treatment options for recurrent or metastatic cases. Immunotherapy offers new hope, as demonstrated by the recent approval of programmed cell death protein 1-blocking antibody for recurrent or metastatic disease. This might be augmented by combination with antigen-specific immunotherapy approaches, such as vaccines or adoptive cell transfer, to enhance the host cellular immune response targeting HPV-positive cancer cells. As cervical cancer progresses, it can foster an immunosuppressive microenvironment and counteract host anticancer immunity. Thus, approaches to reverse suppressive immune environments and bolster effector T-cell functioning are likely to enhance the success of such cervical cancer immunotherapy. The success of nonspecific immunostimulants like imiquimod against genital warts also suggest the possibility of utilizing these immunotherapeutic strategies in cervical cancer prevention to treat precursor lesions (cervical intraepithelial neoplasia) and persistent hrHPV infections against which the licensed prophylactic HPV vaccines have no efficacy. Here, we review the progress and challenges in the development of immunotherapeutic approaches for the prevention and treatment of cervical cancer.

The Prognostic Impact of Circulating Tumour DNA in Melanoma Patients Treated with Systemic Therapies-Beyond BRAF Mutant Detection

In this study, we evaluated the predictive value of circulating tumour DNA (ctDNA) to inform therapeutic outcomes in metastatic melanoma patients receiving systemic therapies. We analysed 142 plasma samples from metastatic melanoma patients prior to commencement of systemic therapy: 70 were treated with BRAF/MEK inhibitors and 72 with immunotherapies. Patient-specific droplet digital polymerase chain reaction assays were designed for ctDNA detection. Plasma ctDNA was detected in 56% of patients prior to first-line anti-PD1 and/or anti-CTLA-4 treatment. The detection rate in the immunotherapy cohort was comparably lower than those with BRAF inhibitors (76%, p = 0.0149). Decreasing ctDNA levels within 12 weeks of treatment was strongly concordant with treatment response (Cohen's k = 0.798, p < 0.001) and predictive of longer progression free survival. Notably, a slower kinetic of ctDNA decline was observed in patients treated with immunotherapy compared to those on BRAF/MEK inhibitors. Whole exome sequencing of ctDNA was also conducted in 9 patients commencing anti-PD-1 therapy to derive tumour mutational burden (TMB) and neoepitope load measurements. The results showed a trend of high TMB and neoepitope load in responders compared to non-responders. Overall, our data suggest that changes in ctDNA can serve as an early indicator of outcomes in metastatic melanoma patients treated with systemic therapies and therefore may serve as a tool to guide treatment decisions.

Immunotherapy in cervix cancer

The treatment approach to cervix cancer has remained unchanged for several decades and new therapeutic strategies are now required to improve outcomes, as the prognosis is still poor. In the last years, a better understanding of HPV tumor-host immune system interactions and the development of new therapeutics targeting immune checkpoints generated interest in the use of immunotherapy in cervix cancer. Preliminary phase I-II trials demonstrated the efficacy, the duration of responses and the manageable safety of this approach. Currently, many phase II and III studies are ongoing in both locally advanced and metastatic cervical cancer, assessing immunotherapy as a single agent or in combination with chemotherapy and radiotherapy. We reviewed the published data and the therapeutic implications of the most promising novel immunotherapeutic agents under investigation in cervix cancer.

Selective Upregulation of CTLA-4 on CD8+ T Cells Restricted by HLA-B*35Px Renders them to an Exhausted Phenotype in HIV-1 infection

HLA-B*35Px is associated with HIV-1 disease rapid progression to AIDS. However, the mechanism(s) underlying this deleterious effect of this HLA allele on HIV-1 infection outcome has not fully understood. CD8⁺ T cells play a crucial role to control the viral replication but impaired CD8⁺ T cells represent a major hallmark of HIV-1 infection. Here, we examined the effector functions of CD8⁺ T cells restricted by HLA-B*35Px (HLA-B*35:03 and HLA-B*35:02), HLA-B*27/B57 and non-HLA-B*27/B57 (e.g. HLA-A*01, A*02, A*03, A*11, A*24, A*26, B*40, B*08, B*38, B*44). CD8⁺ T cells restricted by HLA-B*35Px exhibited an impaired phenotype compared with those restricted by HLA-B*27/B57 and even non-HLA-B*27/B57. CD8⁺ T cells restricted by non-HLA-B*27/B57 when encountered their cognate epitopes upregulated TIM-3 and thus became suppressed by regulatory T cells (Tregs) via TIM-3: Galectin-9 (Gal-9). Strikingly, CD8⁺ T cells restricted by HLA-B*35Px expressed fewer TIM-3 and therefore did not get suppressed by Tregs, which was similar to CD8⁺ T cells restricted by HLA-B*27/B57. Instead, CD8⁺ T cells restricted by HLA-B*35Px upon recognition of their cognate epitopes upregulated CTLA-4. The transcriptional and impaired phenotype (e.g. poor effector functions) of HIV-specific CD8⁺ T cells restricted by HLA-B*35 was related to persistent CTLA-4, elevated Eomes and blimp-1 but poor T-bet expression. As such, anti-CTLA-4 antibody, Ipilimumab, reversed the impaired proliferative capacity of antigen-specific CD8⁺ T cells restricted by HLA-B*35Px but not others. This study supports the concept that CD8⁺ T resistance to Tregs-mediated suppression is related to allele restriction rather than the epitope specificity. Our results aid to explain a novel mechanism for the inability of HIV-specific CD8⁺ T cells restricted by HLA-B*35Px to control viral replication.

A rare group of HIV-infected individuals with HLA-B*35Px rapidly progress to AIDS but those with HLA-B*27 and HLA-B*57 spare disease progression. Previous studies have suggested that viral mutation may prevent a robust immune response against the virus in these with HLA-B*35Px. However, the functionality of HIV-specific CD8⁺ T cells restricted by HLA-B*35Px remains unclear. In this study, we demonstrate that HIV-specific CD8⁺ T cells restricted by HLA-B*35Px (HLA-B*35:03 and HLA-B*35:02) exhibit an impaired phenotype (e.g. low proliferative capacity, poor cytotoxic molecules expression and, poor cytokine production ability). Interestingly, CD8⁺ T cells restricted by HLA-B*27/B*57 evade regulatory T cells (Tregs) suppression but not those restricted by non-HLA-B*27/B*57. CD8⁺ T cells restricted by non-HLA-B*27/B*57 when encountering their epitopes upregulate TIM-3 but not those restricted by HLA-B*27/B*57 and HLA-B*35Px. As a result, CD8⁺ T cells restricted by non-HLA-B*27/B*57 become suppressed by Tregs via TIM-3: Galectin-9 interactions. Strikingly, CD8⁺ T cells restricted by HLA-B*35Px upregulate CTLA-4 when encountering their epitopes, which render them to an exhausted phenotype. This differential response is linked to the up-regulation of Eomes, Blimp-1 but low T-bet expression in CD8⁺ T cells restricted by HLA-B*35Px. These results implicate that reinvigoration of these cells might be feasible using an anti-CTLA-4 antibody.

Tumor lysis syndrome in a patient with metastatic melanoma treated with nivolumab

A 79-year-old man with metastatic melanoma of the right maxillary sinus and multiple liver metastases received a single dose of nivolumab. Eight days later, he experienced impaired consciousness, accompanied by abnormal laboratory and electrocardiographic findings. He was therefore diagnosed with tumor lysis syndrome (TLS). Laboratory and electrocardiographic findings improved immediately after continuous hemodiafiltration; however, he died 22 days after receiving nivolumab. Autopsy revealed massive tumor necrosis in the liver. There are few case reports of TLS associated with immune checkpoint inhibitors, indicating that we should be prepared to manage especially in a patient with liver involvement of high tumor burden.

The glucocorticoids prednisone and dexamethasone differentially modulate T cell function in response to anti-PD-1 and anti-CTLA-4 immune checkpoint blockade

On-treatment steroids for countering immune checkpoint inhibitor-induced inflammatory responses (irAEs) are a hallmark of cancer immunotherapy. However, the suppressive nature of steroids has raised questions regarding their ability to compromise the function of the 'proliferative burst' of effector T cells induced by immune checkpoint antibodies. We investigated the effector functions and the co-inhibitory receptor profile of stimulated peripheral blood mononuclear cells (PBMCs) pre-treated with prednisone and dexamethasone alone or in the presence of anti-PD-1/CTLA-4 antibodies. Also, clinical analysis of a patient who exhibited irAEs following combination (anti-PD-1/CTLA-4) in the presence of glucocorticoids was done. We found that prednisone in contrast to dexamethasone did not compromise T cell cytokine production (IL-2, IFN-γ and TNF-α) and proliferation in the absence or presence of anti-PD-1/CTLA-4 antibodies, when a physiological concentration was used. Neither single prednisone treatment nor co-treatment with checkpoint inhibitors impacted the expression of co-inhibitory receptors PD-1, CTLA-4, TIM-3 and LAG-3. In contrast, dexamethasone treatment promoted downregulation of LAG-3 expression by T cells. In addition, co-treatment of PD-1 + Jurkat cells with prednisone and/or dexamethasone with anti-PD-1 before stimulation significantly reduced SHP-2 phosphorylation, indicative of increased T cell function. Our findings hereby demonstrate a differential steroid effect on T cell function, which should be taken into consideration for patients undergoing immunotherapy. Also, the clinical analysis of a patient who exhibited irAEs following combination (anti-PD-1/CTLA-4) therapy indicated complete metabolic response in the presence of glucocorticoids. Therefore, concomitant use of prednisone does not appear to interfere with the function of immune checkpoint blockade.

Novel Human Anti-PD-L1 mAbs Inhibit Immune-Independent Tumor Cell Growth and PD-L1 Associated Intracellular Signalling

The novel antibody-based immunotherapy in oncology exploits the activation of immune system mediated by immunomodulatory antibodies specific for immune checkpoints. Among them, the programmed death ligand-1 (PD-L1) is of particular interest as it is expressed not only on T-cells, but also on other immune cells and on a large variety of cancer cells, such as breast cancer cells, considering its high expression in both ErbB2-positive and Triple Negative Breast Cancers. We demonstrate here that PD-L1_1, a novel anti-PD-L1 T -cell stimulating antibody, inhibits PD-L1-tumor cell growth also by affecting the intracellular MAPK pathway and by activating caspase 3. Similar in vitro results were obtained for the first time here also with the clinically validated anti-PD-L1 mAb Atezolizumab and in vivo with another validated anti-mouse anti-PD-L1 mAb. Moreover, we found that two high affinity variants of PD-L1_1 inhibited tumor cell viability more efficiently than the parental PD-L1_1 by affecting the same MAPK pathways with a more potent effect. Altogether, these results shed light on the role of PD-L1 in cancer cells and suggest that PD-L1_1 and its high affinity variants could become powerful antitumor weapons to be used alone or in combination with other drugs such as the anti-ErbB2 cAb already successfully tested in in vitro combinatorial treatments.

Novel Human Bispecific Aptamer-Antibody Conjugates for Efficient Cancer Cell Killing

Monoclonal antibodies have been approved by the Food and Drug Administration for the treatment of various human cancers. More recently, oligonucleotide aptamers have risen increasing attention for cancer therapy thanks to their low size (efficient tumor penetration) and lack of immunogenicity, even though the short half-life and lack of effector functions still hinder their clinical applications. Here, we demonstrate, for the first time, that two novel bispecific conjugates, consisting of an anti-epidermal growth factor receptor (EGFR) aptamer linked either with an anti-epidermal growth factor receptor 2 (ErbB2) compact antibody or with an immunomodulatory (anti-PD-L1) antibody, were easily and rapidly obtained. These novel aptamer-antibody conjugates retain the targeting ability of both the parental moieties and acquire a more potent cancer cell killing activity by combining their inhibitory properties. Furthermore, the conjugation of the anti-EGFR aptamer with the immunomodulatory antibody allowed for the efficient redirection and activation of T cells against cancer cells, thus dramatically enhancing the cytotoxicity of the two conjugated partners. We think that these bispecific antibody-aptamer conjugates could have optimal biological features for therapeutic applications, such as increased specificity for tumor cells expressing both targets and improved pharmacokinetic and pharmacodynamic properties due to the combined advantages of the aptamer and antibody.

Small molecule immunomodulation: the tumor microenvironment and overcoming immune escape

Immunotherapy has led to a paradigm shift in the treatment of many advanced malignancies. Despite the success in treatment of tumors like non-small cell lung cancer (NSCLC) and melanoma, checkpoint inhibition-based immunotherapy has limitations. Many tumors, such as pancreatic cancer, are less responsive to checkpoint inhibitors, where patients tend to have a limited duration of benefit and where clinical responses are more robust in patients who are positive for predictive biomarkers. One of the critical factors that influence the efficacy of immunotherapy is the tumor microenvironment (TME), which contains a heterogeneous composition of immunosuppressive cells. Myeloid-derived suppressor cells (MDSCs) and tumor-associated macrophages (TAMs) alter the immune landscape of the TME and serve as facilitators of tumor proliferation, metastatic growth and immunotherapy resistance. Small molecule inhibitors that target these components of the TME have been developed. This special issue review focuses on two promising classes of immunomodulatory small molecule inhibitors: colony stimulating factor-1 receptor (CSF-1R) and focal adhesion kinase (FAK). Small molecule inhibitors of CSF-1R reprogram the TME and TAMs, and lead to enhanced T-cell-mediated tumor eradication. FAK small molecule inhibitors decrease the infiltration MDSCs, TAMs and regulatory T-cells. Additionally, FAK inhibitors are implicated as modulators of stromal density and cancer stem cells, leading to a TME more conducive to an anti-tumor immune response. Immunomodulatory small molecule inhibitors present a unique opportunity to attenuate immune escape of tumors and potentiate the effectiveness of immunotherapy and traditional cytotoxic therapy.

C5a receptors C5aR1 and C5aR2 mediate opposing pathologies in a mouse model of melanoma

The canonical complement component 5a (C5a) receptor (C5aR) 1 has well-described roles in tumorigenesis but the contribution of the second receptor, C5aR2, is unclear. The present study demonstrates that B16.F0 melanoma cells express mRNA for both C5aR1 and C5aR2 and signal through ERK and p38 MAPKs in response to C5a. Despite this, C5a had no impact on melanoma cell proliferation or migration in vitro. In vivo studies demonstrated that the growth of B16.F0 melanoma tumors was increased in C5aR2^-/- mice but reduced in C5aR1^-/- mice and wild-type mice treated with a C5aR1 antagonist. Analysis of tumor-infiltrating leukocyte populations showed no significant differences between wild-type and C5aR2^-/- mice. Conversely, percentages of myeloid-derived suppressor cells, macrophages, and regulatory T lymphocytes were lower in tumors from C5aR1^-/- mice, whereas total (CD3⁺) T lymphocytes and CD4⁺ subsets were higher. Analysis of cytokine and chemokine levels also showed plasma IFN-γ was higher and tumor C-C motif chemokine ligand 2 was lower in the absence of C5aR1. The results suggest that C5aR1 signaling supports melanoma growth by promoting infiltration of immunosuppressive leukocyte populations into the tumor microenvironment, whereas C5aR2 has a more restricted but beneficial role in limiting tumor growth. Overall, these data support the potential of C5aR1-inhibitory therapies for melanoma.-Nabizadeh, J. A., Manthey, H. D., Panagides, N., Steyn, F. J., Lee, J. D., Li, X. X., Akhir, F. N. M., Chen, W., Boyle, G. M., Taylor, S. M., Woodruff, T. M., Rolfe, B. E. C5a receptors C5aR1 and C5aR2 mediate opposing pathologies in a mouse model of melanoma.

Pre-clinical investigation of the synergy effect of interleukin-12 gene-electro-transfer during partially irreversible electropermeabilization against melanoma

BACKGROUND

Melanoma is a very aggressive skin tumor that can be cured when diagnosed and treated in its early stages. However, at the time of identification, the tumor is frequently in a metastatic stage. Intensive research is currently ongoing to improve the efficacy of the immune system in eliminating cancer cells. One approach is to boost the activation of cytotoxic T cells by IL-12 cytokine that plays a central role in the activation of the immune system. In parallel, physical methods such as electropermeabilization-based treatments are currently under investigation and show promising results.

METHODS

In this study, we set electrical parameters to induce a partial-irreversible electropermeabilization (pIRE) of melanoma to induce a sufficient cell death and potential release of tumor antigens able to activate immune cells. This protocol mimics the situation where irreversible electropermeabilization is not fully completed. Then, a peritumoral plasmid IL-12 electrotransfer was combined with pIRE treatment. Evaluation of the tumor growth and survival was performed in mouse strains having a different immunological background (C57Bl/6 (WT), nude and C57Bl6 (TLR9-/-)).

RESULTS

pIRE treatment induced apoptotic cell death and a temporary tumor growth delay in all mouse strains. In C57Bl/6 mice, we showed that peritumoral plasmid IL-12 electrotransfer combined with tumor pIRE treatment induced tumor regression correlating with a local secretion of IL-12 and IFN-γ. This combined treatment induced a growth delay of distant tumors and prevented the emergence of a second tumor in 50% of immunocompetent mice.

CONCLUSIONS

The combination of pIL-12 GET and pIRE not only enhanced survival but could bring a curative effect in wild type mice. This two-step treatment, named Immune-Gene Electro-Therapy (IGET), led to a systemic activation of the adaptive immune system and the development of an anti-tumor immune memory.

From immune checkpoints to vaccines: The past, present and future of cancer immunotherapy

Cancer is a worldwide medical problem with significant repercussions on individual patients and societies as a whole. In order to alter the outcomes of this deadly disease the treatment of cancer over the centuries has undergone a unique evolution. However, utilizing the best treatment modalities and achieving cures or long-term durable responses have been inconsistent and limited, that is until recently. Contemporary research has highlighted a fundamental gap in our understanding of how we approach treating cancer, by revealing the intricate relationship between the immune system and tumors. In this atmosphere, the growth of immunotherapy has not only forever changed our understanding of cancer biology, but the manner by which we treat patients. It's paradigm shifting success has led to the approval of over 10 different immunotherapeutic agents, including checkpoint inhibitors, vaccine-based therapies, oncolytic viruses and T cell directed therapies for nearly 20 different indications across countless tumor types. Despite the breakthroughs that have occurred in the field of immunotherapy, it has not been the panacea for all cancers. With a deeper understanding of the immune system we have been able to peer into tumor immune escape and therapy resistance. Simultaneously this understanding has paved the way for the investigation and development of novel immune system altering agents and combinatorial therapies. In this chapter we review the immune system and its intricate relationship with cancer, the evolution of immunotherapy, its current landscape, and future directions in the context of resistance mechanisms and the challenges faced by immunotherapy against cancer.

Targeting Lineage-specific MITF Pathway in Human Melanoma Cell Lines by A-485, the Selective Small-molecule Inhibitor of p300/CBP

Metastatic melanoma is responsible for approximately 80% of deaths from skin cancer. Microphthalmia-associated transcription factor (MITF) is a melanocyte-specific transcription factor that plays an important role in the differentiation, proliferation, and survival of melanocytes as well as in melanoma oncogenesis. MITF is amplified in approximately 15% of patients with metastatic melanoma. However, no small-molecule inhibitors of MITF currently exist. MITF was shown to associate with p300/CBP, members of the KAT3 family of histone acetyltransferase. p300 and CREB-binding protein (p300/CBP) regulate a wide range of cellular events such as senescence, apoptosis, cell cycle, DNA damage response, and cellular differentiation. p300/CBP act as transcriptional coactivators for multiple proteins in cancers, including oncogenic transcription factors such as MITF. In this study, we showed that our novel p300/CBP catalytic inhibitor, A-485, induces senescence in multiple melanoma cell lines, similar to silencing expression of EP300 (encodes p300) or MITF We did not observe apoptosis and increase invasiveness upon A-485 treatment. A-485 regulates the expression of MITF and its downstream signature genes in melanoma cell lines undergoing senescence. In addition, expression and copy number of MITF is significantly higher in melanoma cell lines that undergo A-485-induced senescence than resistant cell lines. Finally, we showed that A-485 inhibits histone-H3 acetylation but did not displace p300 at promoters of MITF and its putative downstream genes. Taken together, we provide evidence that p300/CBP inhibition suppressed the melanoma-driven transcription factor, MITF, and could be further exploited as a potential therapy for treating melanoma.

Massive parallel screening of phage libraries for the generation of repertoires of human immunomodulatory monoclonal antibodies

Immune checkpoints are emerging as novel targets for cancer therapy, and antibodies against them have shown remarkable clinical efficacy with potential for combination treatments to achieve high therapeutic index. This work aims at providing a novel approach for the generation of several novel human immunomodulatory antibodies capable of binding their targets in their native conformation and useful for therapeutic applications.

We performed a massive parallel screening of phage libraries by using for the first time activated human lymphocytes to generate large collections of single-chain variable fragments (scFvs) against 10 different immune checkpoints: LAG-3, PD-L1, PD-1, TIM3, BTLA, TIGIT, OX40, 4-1BB, CD27 and ICOS. By next-generation sequencing and bioinformatics analysis we ranked individual scFvs in each collection and identified those with the highest level of enrichment.

As a proof of concept of the quality/potency of the binders identified by this approach, human IgGs from three of these collections (i.e., PD-1, PD-L1 and LAG-3) were generated and shown to have comparable or better binding affinity and biological activity than the clinically validated anti-PD-1 mAb nivolumab.

The repertoires generated in this work represent a convenient source of agonistic or antagonistic antibodies against the ‘Checkpoint Immunome’ for preclinical screening and clinical implementation of optimized treatments.

Pseudotime Dynamics in Melanoma Single-Cell Transcriptomes Reveals Different Mechanisms of Tumor Progression

Single-cell transcriptomics has been used for analysis of heterogeneous populations of cells during developmental processes and for analysis of tumor cell heterogeneity. More recently, analysis of pseudotime (PT) dynamics of heterogeneous cell populations has been established as a powerful concept to study developmental processes. Here we perform PT analysis of 3 melanoma short-term cultures with different genetic backgrounds to study specific and concordant properties of PT dynamics of selected cellular programs with impact on melanoma progression. Overall, in our setting of melanoma cells PT dynamics towards higher tumor malignancy appears to be largely driven by cell cycle genes. Single cells of all three short-term cultures show a bipolar expression of microphthalmia-associated transcription factor (MITF) and AXL receptor tyrosine kinase (AXL) signatures. Furthermore, opposing gene expression changes are observed for genes regulated by epigenetic mechanisms suggesting epigenetic reprogramming during melanoma progression. The three melanoma short-term cultures show common themes of PT dynamics such as a stromal signature at initiation, bipolar expression of the MITF/AXL signature and opposing regulation of poised and activated promoters. Differences are observed at the late stage of PT dynamics with high, low or intermediate MITF and anticorrelated AXL signatures. These findings may help to identify targets for interference at different stages of tumor progression.

Nivolumab for Patients With Advanced Melanoma Treated Beyond Progression: Analysis of 2 Phase 3 Clinical Trials

Importance

Immune checkpoint inhibitors have demonstrated atypical response patterns, which may not be fully captured by conventional response criteria. There is a need to better understand the potential benefit of continued immune checkpoint inhibition beyond progression.

Objective

To evaluate the safety and potential benefit of nivolumab (anti-programmed cell death receptor 1) monotherapy beyond Response Evaluation Criteria in Solid Tumors (RECIST) v1.1-defined progression.

Design, Setting, and Participants

Pooled, retrospective analysis of data from phase 3 trials of nivolumab in treatment-naive patients with advanced melanoma (CheckMate 066 or CheckMate 067) conducted at academic and clinical cancer centers. Participants were patients treated beyond first disease progression, defined as those who received their last dose of nivolumab more than 6 weeks after progression (TBP group); and patients not treated beyond progression, who discontinued nivolumab therapy before or at progression (non-TBP group). Data analyses were conducted from November 6, 2015, to January 11, 2017.

Interventions

Nivolumab (3 mg/kg every 2 weeks) administered until progression or unacceptable toxic effects. Patients could be treated beyond progression if deriving apparent clinical benefit and tolerating study drug, at the investigator's discretion.

Main Outcomes and Measures

Tumor response and safety in TBP and non-TBP patients.

Results

Among 526 randomized patients (39% [n = 203] female; median age, 62 years [range, 18-90 years]), 306 (58%) experienced disease progression, including 85 (28%) TBP patients and 221 (72%) non-TBP patients. Twenty-four (28%) of the TBP patients had a target lesion reduction of greater than 30% after progression compared with baseline (TBP>30% group). At the time of this analysis, 65 (76%) TBP patients and 21 (87%) TBP>30% patients were still alive; 27 (32%) and 11 (46%), respectively, continued to receive treatment. Median (range) time from progression to last dose of treatment was 4.7 (1.4-25.8) months for TBP patients and 7.6 (2.4-19.4) months for TBP>30% patients. Median (range) time from progression to greater than 30% tumor reduction was 1.4 (0.2-7.0) months. Treatment-related select grade 3 to 4 adverse events were similar in the TBP and non-TBP groups (5 [6%] and 9 [4%], respectively).

Conclusions and Relevance

A substantial proportion of selected patients treated with frontline nivolumab who were clinically stable and judged to be eligible for treatment beyond RECIST v1.1-defined progression by the treating investigators derived apparent clinical benefit without compromising safety. Further analysis will help define the potential benefit of continued nivolumab treatment beyond progression.

Trial Registration

clinicaltrials.gov Identifiers: NCT01721772 (CheckMate 066) and NCT01844505 (CheckMate 067).

The impact of melanoma genetics on treatment response and resistance in clinical and experimental studies

Recent attempts to characterize the melanoma mutational landscape using high-throughput sequencing technologies have identified new genes and pathways involved in the molecular pathogenesis of melanoma. Apart from mutated BRAF, NRAS, and KIT, a series of new recurrently mutated candidate genes with impact on signaling pathways have been identified such as NF1, PTEN, IDH1, RAC1, ARID2, and TP53. Under targeted treatment using BRAF and MEK1/2 inhibitors either alone or in combination, a majority of patients experience recurrences, which are due to different genetic mechanisms such as gene amplifications of BRAF or NRAS, MEK1/2 and PI3K mutations. In principle, resistance mechanisms converge on two signaling pathways, MAPK and PI3K-AKT-mTOR pathways. Resistance may be due to small subsets of resistant cells within a heterogeneous tumor mass not identified by sequencing of the bulk tumor. Future sequencing studies addressing tumor heterogeneity, e.g., by using single-cell sequencing technology, will most likely improve this situation. Gene expression patterns of metastatic lesions were also shown to predict treatment response, e.g., a MITF-low/NF-κB-high melanoma phenotype is resistant against classical targeted therapies. Finally, more recent treatment approaches using checkpoint inhibitors directed against PD-1 and CTLA-4 are very effective in melanoma and other tumor entities. Here, the mutational and neoantigen load of melanoma lesions may help to predict treatment response. Taken together, the new sequencing, molecular, and bioinformatic technologies exploiting the melanoma genome for treatment decisions have significantly improved our understanding of melanoma pathogenesis, treatment response, and resistance for either targeted treatment or immune checkpoint blockade.

Circulating tumour DNA (ctDNA) as a liquid biopsy for melanoma

Circulating tumour DNA (ctDNA) has emerged as a promising blood-based biomarker for monitoring disease status of patients with advanced cancers. In melanoma, ctDNA has been shown to have clinical value as an alternative tumour source for the detection clinically targetable mutations for the assessment of response to therapy. This review provides a critical summary of the evidence that gives credence to the utility of ctDNA as a biomarker for monitoring of disease status in advanced melanoma and the steps required for its implementation into clinical settings.

Emerging growth factor receptor antagonists for the treatment of advanced melanoma

INTRODUCTION

Therapy for metastatic melanoma has undergone a rapid transformation over the past 5-10 years. Advances in immunotherapy with checkpoint inhibitors, including both anti-CTLA-4 and anti-PD-1/PD-L1, have led to durable responses in up to 50% of patients. As our understanding of the processes driving the transformation of melanocytes has improved, progress in targeted therapies has also continued. Areas covered: Angiogenesis and the tumor's dependence on an expanded vascular supply has been a target for novel therapies since the 1970's, as this tissue is derived from endothelial cells that are genetically stable in adults. A phase II trial studying combined therapy with bevacizumab (an inhibitor of angiogenesis) and ipilimumab found promising results. Other agents such as sorafenib have not been as successful, failing to extend progression free or overall survival in clinical trials. In this paper other targeted growth factor inhibitors will also be discussed. Expert opinion: Ultimately, melanoma may not be vulnerable solely to chemotherapy or targeted therapy, but may be efficaciously treated with immunotherapy due to its high mutational rate resulting in the expression of numerous neo-antigens. Therapies with combinations of agents including growth factor receptor and either other targeted therapies or immunotherapy may be a promising complimentary approach.

Melanoma long non-coding RNA signature predicts prognostic survival and directs clinical risk-specific treatments

BACKGROUND

Various studies have demonstrated that the Breslow thickness, tumor ulceration and mitotic index could serve as prognostic markers in patients with cutaneous melanoma. Recently, however, as these clinicopathological biomarkers lack efficient interpretation of endogenous mechanism of melanoma, the emphasis on the prognosis of melanoma has transformed to molecular tumor markers.

OBJECTIVE

This study was designed to identify survival-related long non-coding RNAs (lncRNAs), and based on the different expressions of these lncRNAs, clinical risk-specific diagnosis and adjuvant therapy could be employed on melanoma patients, especially patients in the early course of disease or patients with a Breslow thickness no more than 2mm.

METHODS

The clinical information and corresponding RNA expression data were obtained from The Cancer Genome Atlas dataset and Gene Expression Omnibus dataset (GSE65904). All samples were categorized into one training dataset and two validation datasets. Cox proportional hazard regression analysis was then used to identify survival-related lncRNAs and risk assessment signature was constructed in training dataset. Kaplan-Meier method was used to estimate the utility of this signature in predicting the duration of survival of patients both in the training dataset and two validation datasets. Meanwhile receiver operating characteristic analyses were used to evaluate the predictive effectiveness of this signature in two validation datasets.

RESULTS

It was found that the signature was effective while used for risk stratification, and Kaplan-Meier analyses indicated that the duration of survival of patients in high-risk groups were significantly shorter than that of low-risk groups. Moreover, areas under the receiver operating characteristic curve were 0.711 (95% confidence interval: 0.618-0.804) and 0.698 (95% confidence interval: 0.614-0.782) when this signature was used to predict the patients' duration of survival in two validation datasets respectively, indicating the superior specificity and sensitivity of this signature.

CONCLUSION

We identified a four-lncRNA prognostic signature with the ability of risk stratification for melanoma patients. Risk score acquired from this signature, combining with differential diagnosis and differential adjuvant therapy, could potentially improve the prognosis quality of life for patients, especially patients in the early course of disease or patients with a Breslow thickness no more than 2mm.

Optimising Cancer Immunotherapy: Challenges and Opportunities

Cancer immunotherapy has moved to the forefront in the treatment of patients with cancer, providing a unique opportunity to achieve dramatic and lasting anti-tumour responses in a variety of tumour types. When it comes to patient selection and development of novel immunotherapeutic agents and combinations, so far we have merely scratched the surface of this therapeutic approach. Leading experts in the field of cancer immunotherapy gathered in Amsterdam, Netherlands, on 21st May 2016 for a Scientific Exchange to discuss the current status of immunotherapy within the field of oncology and explore the future of this evolving therapeutic strategy. Current challenges and limitations regarding the use of immunotherapy were addressed for tumour types such as melanoma, lung cancer, bladder cancer, and renal cell carcinoma (RCC). Recent advances and future directions in the areas of immunotherapy biomarkers and mechanisms of resistance were also examined. Current evidence for combination strategies with immunotherapy was highlighted, including combinations with other immunotherapies or with radiotherapy. Below is a summary of the key points discussed during this scientific exchange.

The Spectrum of Serious Infections Among Patients Receiving Immune Checkpoint Blockade for the Treatment of Melanoma

The risk of infection among patients receiving immune checkpoint blockade is unknown. We retrospectively reviewed medical records of 740 patients with melanoma who received immune checkpoint blockers. Serious infection occurred in 54 patients (7.3%). The main risk factors were receipt of corticosteroids and/or infliximab.

Sneaky side effects and ineffectiveness of an immunotherapy with ipilimumab in a case of metastatic melanoma

Ipilimumab is an anti-CTLA-4 antibody that is approved for the treatment of metastatic malignant melanoma. Side-effects are mostly immune-mediated and in many cases the lack of specific symptoms leads to delayed diagnosis and treatment of adverse events. We present the case of a female patient who experienced an uncommon combination of adverse reactions while undergoing therapy with ipilimumab and where the absence of specificity of the symptoms led to late diagnosis and treatment of side effects. Autoimmune disease was neither associated with tumor response nor with prolonged survival.

Developing immunotherapeutic strategies to target brain tumors

INTRODUCTION

Recent years have seen rapid growth in cancer treatments that enhance the anti-tumor activities of the immune system. Collectively known as immunotherapy, modulation of the immune system has shown success treating some hematological malignancies, but has yet to be successfully applied to the treatment of patients with brain tumors.

AREAS COVERED

This review highlights mechanistic insights from murine studies and compiled recent clinical trial data, focusing on the most aggressive brain tumor, glioblastoma (GBM). The field has recently accumulated a critical mass of data, and we discuss past treatment failures in the context of newly developed approaches now entering clinical trials. This article provides an overview of the immunotherapeutic armamentarium currently in development for the treatment of patients with GBM, who are in dire need of safe and effective therapies. Expert commentary: Themes that emerge include the importance of mitigating the effects of an immunosuppressive tumor microenvironment and the potential for innate immune cell activation to enhance cytotoxic anti-tumor activity. Consideration of these studies as a collective may inform the design of new immunotherapies, as well as the immune monitoring protocols for patients participating in clinical trials.

Immunotherapy for human papillomavirus-associated disease and cervical cancer: review of clinical and translational research

Cervical cancer is the fourth most lethal women's cancer worldwide. Current treatments against cervical cancer include surgery, radiotherapy, chemotherapy, and anti-angiogenic agents. However, despite the various treatments utilized for the treatment of cervical cancer, its disease burden remains a global issue. Persistent infection of human papillomavirus (HPV) has been identified as an essential step of pathogenesis of cervical cancer and many other cancers, and nation-wide HPV screening as well as preventative HPV vaccination program have been introduced globally. However, even though the commercially available prophylactic HPV vaccines, Gardasil (Merck) and Cervarix (GlaxoSmithKline), are effective in blocking the entry of HPV into the epithelium of cervix through generation of HPV-specific neutralizing antibodies, they cannot eliminate the pre-existing HPV infection. For these reason, other immunotherapeutic options against HPV-associated diseases, including therapeutic vaccines, have been continuously explored. Therapeutic HPV vaccines enhance cell-mediated immunity targeting HPV E6 and E7 antigens by modulating primarily dendritic cells and cytotoxic T lymphocyte. Our review will cover various therapeutic vaccines in development for the treatment of HPV-associated lesions and cancers. Furthermore, we will discuss the potential of immune checkpoint inhibitors that have recently been adopted and tested for their treatment efficacy against HPV-induced cervical cancer.

Quantitative CD3 PET Imaging Predicts Tumor Growth Response to Anti-CTLA-4 Therapy

Immune checkpoint inhibitors have made rapid advances, resulting in multiple Food and Drug Administration-approved therapeutics that have markedly improved survival. However, these benefits are limited to a minority subpopulation that achieves a response. Predicting which patients are most likely to benefit would be valuable for individual therapy optimization. T-cell markers such as CD3-by examining active recruitment of the T cells responsible for cancer-cell death-represent a more direct approach to monitoring tumor immune response than pretreatment biopsy or genetic screening. This approach could be especially effective as numerous different therapeutic strategies emerge, decreasing the need for drug-specific biomarkers and instead focusing on T-cell infiltration, which has been previously correlated with treatment response.

METHODS

A CD3 PET imaging agent targeting T cells was synthesized to test the role of such imaging as a predictive marker. The ⁸⁹Zr-p-isothiocyanatobenzyl-deferoxamine-CD3 PET probe was assessed in a murine tumor xenograft model of anti-cytotoxic T-lymphocyte antigen-4 (CTLA-4) immunotherapy of colon cancer.

RESULTS

Imaging on day 14 revealed 2 distinct groups of mice stratified by PET signal intensity. Although there was no significant difference in tumor volume on the day of imaging, in the high-uptake group subsequent measurements revealed significantly smaller tumors than in either the low-uptake group or the untreated controls. In contrast, there was no significant difference in the size of tumors between the low-uptake and untreated control mice.

CONCLUSION

These findings indicate that high CD3 PET uptake in the anti-CTLA-4-treated mice correlated with subsequent reduced tumor volume and was a predictive biomarker of response.