Research Trends in Immune Checkpoint Blockade for Melanoma: Visualization and Bibliometric Analysis.

BACKGROUND: Melanoma is one of the most life-threatening skin cancers; immune checkpoint blockade is widely used in the treatment of melanoma because of its remarkable efficacy. OBJECTIVE: This study aimed to conduct a comprehensive bibliometric analysis of research conducted in recent decades on immune checkpoint blockade for melanoma, while exploring research trends and public interest in this topic. METHODS: We summarized the articles in the Web of Science Core Collection on immune checkpoint blockade for melanoma in each year from 1999 to 2020. The R package bibliometrix was used for data extraction and visualization of the distribution of publication year and the top 10 core authors. Keyword citation burst analysis and cocitation networks were calculated with CiteSpace. A Gunn online world map was used to evaluate distribution by country and region. Ranking was performed using the Standard Competition Ranking method. Coauthorship analysis and co-occurrence were analyzed and visualized with VOSviewer. RESULTS: After removing duplicates, a total of 9169 publications were included. The distribution of publications by year showed that the number of publications rose sharply from 2015 onwards and either reached a peak in 2020 or has yet to reach a peak. The geographical distribution indicated that there was a large gap between the number of publications in the United States and other countries. The coauthorship analysis showed that the 149 top institutions were grouped into 8 clusters, each covering approximately a single country, suggesting that international cooperation among institutions should be strengthened. The core author extraction revealed changes in the most prolific authors. The keyword analysis revealed clustering and top citation bursts. The cocitation analysis of references from 2010 to 2020 revealed the number of citations and the centrality of the top articles. CONCLUSIONS: This study revealed trends in research and public interest in immune checkpoint blockade for melanoma. Our findings suggest that the field is growing rapidly, has several core authors, and that the United States is taking the lead position. Moreover, cooperation between countries should be strengthened, and future research hot spots might focus on deeper exploration of drug mechanisms, prediction of treatment efficacy, prediction of adverse events, and new modes of administration, such as combination therapy, which may pave the way for further research.

Albendazole induces immunotherapy response by facilitating ubiquitin-mediated PD-L1 degradation.

BACKGROUND: Immune checkpoint inhibitors (ICIs) have been increasingly used in patients with various cancers and have shown efficient therapeutic outcomes. However, fewer than 40% of cases across multiple cancer types show a response to ICIs. Therefore, developing more efficient combinational approaches with ICIs and revealing the underlying mechanisms are important goals for achieving rapid clinical transformation and application. METHODS: The effects on antitumor immunity activity of albendazole (ABZ) and the synergistic effects of ABZ with CD73 blockade were investigated in the melanoma B16F10 and the Lewis lung cancer tumor-bearing immune-competent mice models. The mechanism of ABZ reducing PD-L1 protein level through suppressing UBQLN4 was identified and validated through immunoprecipitation-mass spectrometry and molecular methods. Bioinformatics and anti-PD-1 therapy melanoma patients samples analysis were used to assess the level of UBQLN4/PD-L1 in the therapeutic efficacy of anti-PD-1 therapy. RESULTS: ABZ induces CD8+ T cell activity and subsequent immunotherapy response associated with suppression of PD-L1 protein level. Mechanistically, we revealed that ABZ promotes ubiquitin-mediated degradation of PD-L1 via suppressing UBQLN4, which was bound to PD-L1 and stabilized PD-L1 protein. Preclinically, genetic deletion or target inhibition of CD73 showed synergistic effects with ABZ treatment in the immune-competent mice models. Significantly, UBQLN4 and PD-L1 levels were higher in the tumor region of responders versus non-responders and correlated with better progression-free survival and overall survival in anti-PD-1 therapy melanoma patients. CONCLUSIONS: Our findings revealed a previously unappreciated role of ABZ in antitumor immunity by inducing ubiquitin-mediated PD-L1 protein degradation, identified predictors for assessing the therapeutic efficacy of anti-PD-1 therapy, and provided novel therapeutic possibility by combination treatment of ABZ and CD73 blockade in cancers.

Ag nanoparticles enhance immune checkpoint blockade efficacy by promoting of immune surveillance in melanoma.

Immune checkpoint blockade (ICB) therapy, represented by programmed cell death protein 1 (PD-1) and its ligand (PD-L1) monoclonal antibodies (mAbs), has shown an obvious benefit for melanoma immunotherapy, but the overall response rate is still low. To find an effective combination therapy strategy, we successfully produced small size silver nanoparticles coated with sucrose (S-AgNPs) as potent adjuvants. The antitumor effects of S-AgNPs were tested in vitro and comparatively investigated in immunodeficient and immunocompetent mice with melanoma. Fluorescence-activated cell sorting and immunofluorescent staining analysis were conducted to identify the tumor microenvironments. The expression of PD-L1 in tumors was tested by multiple methods. The combination therapy and potential toxicity of S-AgNPs and PD-1 mAbs were assessed in melanoma-bearing mice. In our findings, S-AgNPs presented potent antitumor effects, good druggability and low systemic toxicity. Functionally, we found that S-AgNPs exhibited better antitumor effects in immunocompetent mice. Mechanistically, we showed that S-AgNPs suppress tumor cell proliferation by inducing cellular apoptosis and promote cytotoxic CD8+ T cell infiltration and activity. Preclinically, S-AgNPs showed excellent local antitumor activity and mild systemic immunotoxicity with PD-1 mAbs in the inhibition of melanoma proliferation, providing a novel clinical combination treatment strategy.

Profiling of immune features to predict immunotherapy efficacy.

Immune checkpoint blockade (ICB) therapies exhibit substantial clinical benefit in different cancers, but relatively low response rates in the majority of patients highlight the need to understand mutual relationships among immune features. Here, we reveal overall positive correlations among immune checkpoints and immune cell populations. Clinically, patients benefiting from ICB exhibited increases for both immune stimulatory and inhibitory features after initiation of therapy, suggesting that the activation of the immune microenvironment might serve as the biomarker to predict immune response. As proof-of-concept, we demonstrated that the immune activation score (IS Δ) based on dynamic alteration of interleukins in patient plasma as early as two cycles (4-6 weeks) after starting immunotherapy can accurately predict immunotherapy efficacy. Our results reveal a systematic landscape of associations among immune features and provide a noninvasive, cost-effective, and time-efficient approach based on dynamic profiling of pre- and on-treatment plasma to predict immunotherapy efficacy.

Pharmacological inhibition of USP7 suppresses growth and metastasis of melanoma cells in vitro and in vivo.

Melanoma is a highly aggressive type of skin cancer. The development of diverse resistance mechanisms and severe adverse effects significantly limit the efficiency of current therapeutic approaches. Identification of the new therapeutic targets involved in the pathogenesis will benefit the development of novel therapeutic strategies. The deubiquitinase ubiquitin-specific protease-7, a potential target for cancer treatment, is deregulated in types of cancer, but its role in melanoma is still unclear. We investigated the role and the inhibitor P22077 of ubiquitin-specific protease-7 in melanoma treatment. We found that ubiquitin-specific protease-7 was overexpressed and correlated with poor prognosis in melanoma. Further, pharmacological inhibition of ubiquitin-specific protease-7 by P22077 can effectively inhibit proliferation, and induce cell cycle arrest and apoptosis via ROS accumulation-induced DNA damage in melanoma cells. Inhibition of ubiquitin-specific protease-7 by P22077 also inhibits melanoma tumour growth in vivo. Moreover, inhibition of ubiquitin-specific protease-7 prevented migration and invasion of melanoma cells in vitro and in vivo by decreasing the Wnt/ß-catenin signalling pathway. Taken together, our study revealed that ubiquitin-specific protease-7 acted as an oncogene involved in melanoma cell proliferation and metastasis. Therefore, ubiquitin-specific protease-7 may serve as potential candidates for the treatment of melanoma.

The Beneficial Role of Sunitinib in Tumor Immune Surveillance by Regulating Tumor PD-L1.

Immune checkpoints blockades have shown promising clinical effects in various malignancies, but the overall response rate is low. Here, the immune features are comprehensively characterized in >10 000 cancer patients from The Cancer Genome Atlas and significantly positive correlations are observed between targets of Sunitinib and inhibitory immune checkpoints and suppressive immune cells. It is further confirmed that Sunitinib treatment increases the antitumor immunity in a phase III trial. Mechanistically, it is discovered that Sunitinib regulates the stability of tumor PD-L1 via p62, that p62 can bind to PD-L1 and specifically promote its translocation into autophagic lysosome for degradation. Preclinically, Sunitinib shows a synergistic antitumor effect with cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) monoclonal antibody (mAb) in melanoma and nonsmall cell lung cancer (NSCLC) immune competent mice by promoting the tumor-infiltrating lymphocytes activity. Clinically, a higher PD-L1 level but a lower p62 level in the tumor region of responders as compared to those of nonresponders among anti-PD-1-treated NSCLC patients is observed. Taken together, by utilizing rigorous computational analysis, functional characterization in vitro and in vivo, and neoadjuvent clinical trial, a novel molecular mechanism is revealed regarding the regulation of PD-L1 via p62, thus providing a novel therapeutic strategy by the combination treatment of CTLA-4 with Sunitinib.

Small-molecule MMP2/MMP9 inhibitor SB-3CT modulates tumor immune surveillance by regulating PD-L1.

BACKGROUND: Immune checkpoint blockade (ICB) therapy has demonstrated considerable clinical benefit in several malignancies, but has shown favorable response in only a small proportion of cancer patients. Recent studies have shown that matrix metalloproteinases (MMPs) are highly associated with the microenvironment of tumors and immune cells. However, it is unknown whether MMPs are involved in immunotherapy. METHODS: Here, we used integrative analysis to explore the expression landscape of the MMP family and its association with immune features across multiple cancer types. We used T cell cytotoxicity-mediated tumor killing assay to determine the co-cultured T cell activity of SB-3CT, an MMP2/9 inhibitor. We then used in vitro assays to examine the regulating roles of SB-3CT on PD-L1. We further characterized the efficacy of SB-3CT, in combination with anti-PD-1 and/or anti-CTLA4 treatment in mouse models with melanoma and lung cancer. RESULTS: Our computational analysis demonstrated a strong association between MMP2/9 and immune features. We demonstrated that inhibition of MMP2/9 by SB-3CT significantly reduced the tumor burden and improved survival time by promoting anti-tumor immunity. Mechanistically, we showed that SB-3CT treatment significantly diminished both mRNA and protein levels of PD-L1 in cancer cells. Pre-clinically, SB-3CT treatment enhanced the therapeutic efficacy of PD-1 or CTLA-4 blockade in the treatment of both primary and metastatic tumors. CONCLUSIONS: Our study unraveled novel molecular mechanisms regarding the regulation of tumor PD-L1 and provided a novel combination therapeutic strategy of SB-3CT and ICB therapy to enhance the efficacy of immunotherapy.

ADORA1 Inhibition Promotes Tumor Immune Evasion by Regulating the ATF3-PD-L1 Axis.

Here, we show that tumor ADORA1 deletion suppresses cell growth in human melanoma cell lines in vitro and tumor development in vivo in immune-deficient xenografts. However, this deletion induces the upregulation of PD-L1 levels, which inactivates cocultured T cells in vitro, compromises anti-tumor immunity in vivo, and reduces anti-tumor efficacy in an immune-competent mouse model. Functionally, PD-1 mAb treatment enhances the efficacy of ADORA1-deficient or ADORA1 antagonist-treated melanoma and NSCLC immune-competent mouse models. Mechanistically, we identify ATF3 as the factor transcriptionally upregulating PD-L1 expression. Tumor ATF3 deletion improves the effect of ADORA1 antagonist treatment of melanoma and NSCLC xenografts. We observe higher ADORA1, lower ATF3, and lower PD-L1 expression levels in tumor tissues from nonresponders among PD-1 mAb-treated NSCLC patients.

Role of purines in regulation of metabolic reprogramming.

Purines, among most influential molecules, are reported to have essential biological function by regulating various cell types. A large number of studies have led to the discovery of many biological functions of the purine nucleotides such as ATP, ADP, and adenosine, as signaling molecules that engage G protein-coupled or ligand-gated ion channel receptors. The role of purines in the regulation of cellular functions at the gene or protein level has been well documented. With the advances in multiomics, including those from metabolomic and bioinformatic analyses, metabolic reprogramming was identified as a key mechanism involved in the regulation of cellular function under physiological or pathological conditions. Recent studies suggest that purines or purine-derived products contribute to important regulatory functions in many fundamental biological and pathological processes related to metabolic reprogramming. Therefore, this review summarizes the role and potential mechanism of purines in the regulation of metabolic reprogramming. In particular, the molecular mechanisms of extracellular purine- and intracellular purine-mediated metabolic regulation in various cells during disease development are discussed. In summary, our review provides an extensive resource for studying the regulatory role of purines in metabolic reprogramming and sheds light on the utilization of the corresponding peptides or proteins for disease diagnosis and therapy.

Propranolol enhanced the anti-tumor effect of sunitinib by inhibiting proliferation and inducing G0/G1/S phase arrest in malignant melanoma.

Both sunitinib, a multi-target tyrosine kinase inhibitor (TKI) and propranolol, a non-selective ß-blocker, have proven therapeutic effects on malignant melanoma (MM). This study reports a synergistic effect of propranolol and sunitinib upon A375, P8 MM cell lines and mice xenografts. Cell viability assays detected a significant decrease of sunitinib IC50 in combination with propranolol, which was confirmed by a colony formation assay. Western blot showed that propranolol and sunitinib combination significantly down-regulated phospho-Rb, phospho-ERK, Cyclin D1, and Cyclin E, but had no effect on Bax, Bcl-2, or cleaved PARP expression. The average tumor size of propranolol and low-dose sunitinib (Sun L) combination treated mice was reduced and similar to high-dose sunitinib treated A375 xenografts. The Ki67 index was significantly reduced in propranolol and Sun L combination treated group compared with single Sun L treated group. This synergistic effect between propranolol and sunitinib to inhibit MM proliferation was through suppressing ERK/Cyclin D1/Rb/Cyclin E pathways and inducing G0/G1/S phase arrest, rather than by inducing tumor cell apoptosis.

Tandem repeats of TSER significantly influence the efficacy of 5-fluorouracil in the treatment of plantar warts.

AIM: To identify potential genetic risk markers associated with 5-fluorouracil (5-FU) treatment outcomes in plantar warts patients. METHODS: In this study, 126 plantar warts patients were treated with an intralesional mixture of 5-FU, lidocaine and epinephrine. Treatment outcomes were compared with DNA mutation analysis. RESULTS: More patients with TSER 3R/3R genotype failed 5-FU treatment than TSER 2R/3R+2R/2R (72.1 vs 43.8%; odds ratio: 3.32; 95% CI: 1.26-8.72; p = 0.013). In addition, the regression modeling identified patient age and TSER 3R allele as covariates of the risk of 5-FU treatment failure (p = 0.025). CONCLUSION:  TSER 3R/3R of TYMS gene was found to be the major risk of treatment failure. This genetic marker provides a potential treatment stratification target to modulate 5-FU treatment in plantar wart patients.