scholarly journals 947 Recombinant myxoma virus MC509-N1 demonstrates antitumor efficacy as monotherapy and in combination with immune checkpoint inhibitors

2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A996-A996
Author(s):  
Enkhtaivan Gansukh ◽  
Tommy Alain ◽  
Tae-Geuk Kim ◽  
Ye-Na Namgung ◽  
Ka-Yeon Son ◽  
...  

BackgroundThere are several obstacles to effective cancer immunotherapy including the heterogenic immune profile and the state of the tumor microenvironment. Oncolytic virotherapy provides an opportunity to overcome some of these limitations through high viral replication and the expression of therapeutic transgenes (TGs) within the tumor tissue. Myxoma virus (MYXV) belongs to the family of Poxviridae and represents a potent oncolytic virus and a safe platform as this virus is non-pathogenic in any hosts apart from lagomorphs. Importantly, MYXV has a high capacity of encoding for multiple TG payloads. Here we engineered MC509-N1, a novel double-encoding transgenes (TG1 and TG2) oncolytic MYXV designed for intravenous (IV) injection. The therapeutic TG1 acts to modify and remodel the immune state of the tumor microenvironment, and TG2 allows for prolonged self-evasion from the host immune defense.MethodsTransgenes expression upon infection was detected by ELISA and by flow cytometry. To determine anticancer efficacy, syngeneic B16F10 melanoma or MC38 colorectal cancer-bearing C57BL/6 mice were injected with MC509-N1 intratumorally or IV with or without immune checkpoint inhibitor (ICI). Tumor growth and survival was monitored after treatment and the immune profile within the tumor microenvironment was analyzed by flow cytometry. Mice cured of their tumors from the original treatment were rechallenged with primary tumor cells to examine anticancer immunity.ResultsCells upon infection with MC509-N1 were found to express both transgenes at high levels and stimulate downstream mechanisms. Importantly, the engineering of both transgenes did not affect MC509-N1 infectivity and productivity as compared to wild-type MYXV. Intratumoral injections of MC509-N1 effectively suppressed tumor growth and improved overall survival of both syngeneic cancer models. Furthermore, MC509-N1 therapy effectively modulated the immune profile within the tumor microenvironment, especially the ratio between tumor infiltrated CD8+ cytotoxic T cells and CD4+FoxP3+ T regulatory cells. In addition, IV injections of MC509-N1 showed improved inhibition of tumor growth compared to wild type MYXV. The combination therapy of MC509-N1 with the ICI anti-PD-L1 further promoted inhibition of tumor growth as demonstrated by higher rate of complete regression and improved survival rate. Furthermore, rechallenge experiments revealed that this combination regimen established specific anticancer immune memory and protected from cancer recurrence.ConclusionsOur results demonstrate that the novel engineered MC509-N1 exhibits potent anticancer efficacy, adequately modulates the immune state of the tumor microenvironment, and acts synergistically to eliminate cancer in combination with ICI.

2016 ◽  
Vol 113 (48) ◽  
pp. E7808-E7817 ◽  
Author(s):  
Lilach Gutter-Kapon ◽  
Dror Alishekevitz ◽  
Yuval Shaked ◽  
Jin-Ping Li ◽  
Ami Aronheim ◽  
...  

The emerging role of heparanase in tumor initiation, growth, metastasis, and chemoresistance is well recognized and is encouraging the development of heparanase inhibitors as anticancer drugs. Unlike the function of heparanase in cancer cells, very little attention has been given to heparanase contributed by cells composing the tumor microenvironment. Here we used a genetic approach and examined the behavior and function of macrophages isolated from wild-type (WT) and heparanase-knockout (Hpa-KO) mice. Hpa-KO macrophages express lower levels of cytokines (e.g., TNFα, IL1-β) and exhibit lower motility and phagocytic capacities. Intriguingly, inoculation of control monocytes together with Lewis lung carcinoma (LLC) cells into Hpa-KO mice resulted in nearly complete inhibition of tumor growth. In striking contrast, inoculating LLC cells together with monocytes isolated from Hpa-KO mice did not affect tumor growth, indicating that heparanase is critically required for activation and function of macrophages. Mechanistically, we describe a linear cascade by which heparanase activates Erk, p38, and JNK signaling in macrophages, leading to increased c-Fos levels and induction of cytokine expression in a manner that apparently does not require heparanase enzymatic activity. These results identify heparanase as a key mediator of macrophage activation and function in tumorigenesis and cross-talk with the tumor microenvironment.


Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 1394-1394 ◽  
Author(s):  
Meenal Shukla ◽  
Venkaiah Betapudi ◽  
Ravi Kumar Alluri ◽  
Sergei Merkulov ◽  
James Hale ◽  
...  

Abstract Introduction High molecular weight kininogen (HK) is a central component of the contact activation and kallikrein-kinin systems. We have previously reported that the cleaved, bradykinin-free form of HK (HKa) induces apoptosis of proliferating endothelial cells and inhibits angiogenesis, and that tumors grow larger and more quickly in kininogen deficient (mKng1-/-) mice. However, HK is known to interact with many different cell types, and the mechanism by which it inhibits tumor growth in vivo is uncertain. Here, we address this question by comparing protein expression and localization in wild type and mKng1-/- mice harboring experimental tumors. Methods A syngeneic tumor model in which 1 x 106 B16F10 melanoma cells cultured in log-growth phase were implanted subcutaneously in the flanks of wild-type and mKng1-/- mice was used in these studies. Tumor growth and animal condition were monitored daily. Parallel studies were performed in tumors from mKng1-/- mice treated immediately prior to tumor implantation with a lentiviral vector that was either empty (control) or contained cDNA for murine Kng1. Mice were sacrificed approximately 17 days after tumor cell implantation, at which time the size of tumors in mKng1-/- mice were ~ 1.5 cm, substantially greater than that in wild-type mice. Tumors were harvested at the time of sacrifice and processed for flow cytometry, immunohistochemistry, immunoblot and antibody array (Proteome Profiler, Angiogenesis Protein Array, RND Systems). Changes in protein levels seen on arrays were confirmed by immunoblotting. Results Tumors in mKng1-/- mice grew more rapidly and had a volume 2-3-fold greater than those in wild-type mice by day 17; these tumors also demonstrated increased vascular density. Antibody array and immunoblot analysis demonstrated increased expression of several tumor and stroma associated proteins including MMP3, MMP9, VEGF, PlGF2, CD44 and MCP1 in tumors from mKng1-/- mice; the same differences were observed between mKng1-/- mice treated with an empty lentivirus when compared to mKng1-/- mice in which kininogen expression was restored using lentivirus-HK. Cellular localization by immunohistochemistry and immunofluorescence staining further demonstrated expression of MMP3 and MMP9 primarily in the tumor compartment, while expression of VEGF was most prominent in the stroma. PLGF2 expression was highly localized to regions immediately surrounding tumor vasculature. Increased, diffuse expression of CD44, a stem cell marker, was evident in tumors from mKng1-/- mice, localized primarily to the tumor compartment; increased CD44 expression was confirmed by flow cytometry and cell sorting, and may suggest increased numbers of tumor stem cells in tumors from mKng1-/- mice, though expression of CD34+, FLK1+, and CD133+ was unaltered. Tumor associated macrophages were significantly reduced in tumors from mKng1-/- mice as demonstrated by F4/80 immunostaining. Conclusions While the anti-angiogenic activity of HKa likely contributes to the increased growth of tumors in mKng1-/- mice, these findings suggest that HK/HKa may also have profound effects on multiple cell types in the tumor microenvironment, including suppression of MMP, VEGF and PLGF2 expression. HKa may also inhibit the tumor stem cell compartment, though further characterization of the CD44 positive cell population in these tumors is needed. Additional studies are needed to better define the interactions of HK/HKa with these diverse cell types. Disclosures No relevant conflicts of interest to declare.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
A. Farias ◽  
A. Soto ◽  
F. Puttur ◽  
C. J. Goldin ◽  
S. Sosa ◽  
...  

AbstractBrucella lumazine synthase (BLS) is a homodecameric protein that activates dendritic cells via toll like receptor 4, inducing the secretion of pro-inflammatory cytokines and chemokines. We have previously shown that BLS has a therapeutic effect in B16 melanoma-bearing mice only when administered at early stages of tumor growth. In this work, we study the mechanisms underlying the therapeutic effect of BLS, by analyzing the tumor microenvironment. Administration of BLS at early stages of tumor growth induces high levels of serum IFN-γ, as well as an increment of hematopoietic immune cells within the tumor. Moreover, BLS-treatment increases the ratio of effector to regulatory cells. However, all treated mice eventually succumb to the tumors. Therefore, we combined BLS administration with anti-PD-1 treatment. Combined treatment increases the outcome of both monotherapies. In conclusion, we show that the absence of the therapeutic effect at late stages of tumor growth correlates with low levels of serum IFN-γ and lower infiltration of immune cells in the tumor, both of which are essential to delay tumor growth. Furthermore, the combined treatment of BLS and PD-1 blockade shows that BLS could be exploited as an essential immunomodulator in combination therapy with an immune checkpoint blockade to treat skin cancer.


2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Jia-Wei Luo ◽  
Yan-Hua Guo ◽  
Feng-Ying Wu ◽  
Xue-Fei Li ◽  
Xue-Cheng Sun ◽  
...  

Recent clinical trials of lung adenocarcinoma with immune checkpoint inhibitors revealed that lung adenocarcinoma patients with EGFR mutations have a poor response to immunotherapy. However, the mechanisms have not been addressed. We performed immunohistochemistry analyses of resected lung adenocarcinoma tissues with and without EGFR mutations to investigate and compare the characteristics of the tumor microenvironment (TME). We retrospectively enrolled a total of 323 lung adenocarcinoma patients (164 had EGFR mutations), and their corresponding tissue samples were analyzed by the EGFR mutation test and immunohistochemistry. We selected the markers of the immune checkpoint molecule (PD1, PD-L1, and LAG-3) and immune cell (CD3, CD4, CD8, and Foxp3) as markers of the tumor microenvironment. Our results revealed that patients had a distinct tumor microenvironment between EGFR-mutant and wild-type lung adenocarcinomas; the expression of CD3, CD4, PD-L1, and Foxp3 in EGFR-mutant tumors was significantly higher than that in wild-type tumors, while the expression of LAG3 and PD-1 showed a positive correlation with EGFR-wild-type tumors. In survival analysis, EGFR-wild-type patients had longer disease-free survival (DFS) than EGFR-mutant patients ( P = 0.0065 ). Our research demonstrates significant differences in tumor microenvironment composition between EGFR-mutant and wild-type patients. Our findings provide novel evidence that contributes to understanding the mechanism underlying the poor efficacy of immune checkpoint inhibitors.


2018 ◽  
Vol 36 (5_suppl) ◽  
pp. 178-178
Author(s):  
Hongjae Chon

178 Background: Cancer immunotherapy targeting immune checkpoints are now emerging as a promising therapeutic strategy in various tumors. However, the treatment of T cell non-inflamed tumor which lacks intratumoral T cell infiltrates are still major clinical hurdle. Therefore, drugs that target signaling pathways to increase T cell infiltration in non-inflamed tumor microenvironment (TME) should be investigated. In this study, we aimed to explore the therapeutic potential of STING agonist in murine model of non-small cell lung cancer to overcome immunotherapy resistance. Methods: C57BL/6 mice, which are 6 to 8 weeks of age, were used for the experiment. Mice were injected with Lewis lung carcinoma cells on the right flank. STING agonist (cGAMP) was injected intratumorally. CD8+ and CD31+ cells were detected using immunofluorescence (IF) staining. Gene expressions of tumor microenvironment were analyzed by NanoString RNA sequencing. Flow cytometry (FACS) was performed to detect CD8+, CD4+, Treg and myeloid cell population. Tumor growths were evaluated in combination with anti-PD1 and STING agonist treatment. Results: Local injection of STING agonist effectively delayed tumor growth of LLC. STING agonist increased intratumoral CD8+ T cells and vascular disruption. Expressions of inhibitory checkpoint molecules (PD-1, PD-L1), cytokines (IFN), CD8+ and CD4+ T cells were increased, which showed that anti-cancer immune responses were augmented. Combination treatment of anti-PD-1 antibody and STING agonist synergistically decreased tumor growth. Conclusions: In this study, STING agonist was shown to delay tumor growth and remodel tumor microenvironment in non-inflamed lung carcinoma model. Combination therapy of STING agonist and immune checkpoint inhibitors (ICI) targeting PD-1 synergistically suppressed the growth of lung cancer which is resistant to ICI monotherapy. Collectively, our findings demonstrated that localized STING therapy effectively sensitizes non-inflamed lung cancer to systemic ICI treatment and induces a maximal anti-cancer immune response.


Author(s):  
Crescenzo D’Alterio ◽  
Maria Buoncervello ◽  
Caterina Ieranò ◽  
Maria Napolitano ◽  
Luigi Portella ◽  
...  

Abstract Background Inefficient T-cell access to the tumor microenvironment (TME) is among the causes of tumor immune-resistance. Previous evidence demonstrated that targeting CXCR4 improves anti-PD-1/PD-L1 efficacy reshaping TME. To evaluate the role of newly developed CXCR4 antagonists (PCT/IB2011/000120/ EP2528936B1/US2013/0079292A1) in potentiating anti-PD-1 efficacy two syngeneic murine models, the MC38 colon cancer and the B16 melanoma-human CXCR4-transduced, were employed. Methods Mice were subcutaneously injected with MC38 (1 × 106) or B16-hCXCR4 (5 × 105). After two weeks, tumors bearing mice were intraperitoneally (ip) treated with murine anti-PD-1 [RMP1–14] (5 mg/kg, twice week for 2 weeks), Pep R (2 mg/kg, 5 days per week for 2 weeks), or both agents. The TME was evaluated through immunohistochemistry and flow-cytometry. In addition, the effects of the human-anti-PD-1 nivolumab and/or Peptide-R54 (Pep R54), were evaluated on human melanoma PES43 cells and xenografts treated. Results The combined treatment, Pep R plus anti-PD-1, reduced the MC38 Relative Tumor Volume (RTV) by 2.67 fold (p = 0.038) while nor anti-PD-1, neither Pep R significantly impacted on tumor growth. Significant higher number of Granzyme B (GZMB) positive cells was detected in MC38 tumors from mice treated with the combined treatment (p = 0.016) while anti-PD-1 determined a modest but significant increase of tumor-infiltrating GZMB positive cells (p = 0.035). Also, a lower number of FoxP3 positive cells was detected (p = 0.022). In the B16-hCXCR4 tumors, two weeks of combined treatment reduced tumor volume by 2.27 fold while nor anti-PD-1 neither Pep R significantly impacted on tumor growth. A significant higher number of GRZB positive cells was observed in B16-hCXCR4 tumors treated with combined treatment (p = 0,0015) as compared to anti-PD-1 (p = 0.028). The combined treatment reduced CXCR4, CXCL12 and PD-L1 expression in MC38 tumors. In addition, flow cytometry on fresh B16-hCXCR4 tumors showed significantly higher Tregs number following anti-PD-1 partially reversed by the combined treatment Pep R and anti-PD-1. Combined treatment determined an increase of CD8/Tregs and CD8/MDSC ratio. To dissect the effect of anti-PD-1 and CXCR4 targeting on PD-1 expressed by human cancer cells, PES43 human melanoma xenograft model was employed. In vitro human anti-PD-1 nivolumab or pembrolizumab (10 μM) reduced PES43 cells growth while nivolumab (10 μM) inhibited pERK1/2, P38 MAPK, pAKT and p4EBP. PES43 xenograft mice were treated with Pep R54, a newly developed Pep R derivative (AcHN-Arg-Ala-[DCys-Arg- Nal(2′)-His-Pen]- COOH), plus nivolumab. After 3 weeks of combined treatment a significant reduction in tumor growth was shown (p = 0.038). PES43 lung disseminated tumor cells (DTC) were detected in fresh lung tissues as melanoma positive MCSP-APC+ cells. Although not statistically significant, DTC-PES43 cells were reduced in mice lungs treated with combined treatment while nivolumab or Pep R54 did not affect DTC number. Conclusion Combined treatment with the new developed CXCR4 antagonist, Pep R, plus anti-PD-1, reduced tumor-growth in two syngeneic murine models, anti-PD-1 sensitive and resistant, potentiating Granzyme and reducing Foxp3 cells infiltration. In addition, the human specific CXCR4 antagonist, Pep R54, cooperated with nivolumab in inhibiting the growth of the PD-1 expressing human PES43 melanoma xenograft. This evidence sheds light on PD-1 targeting mechanisms and paves the way for CXCR4/PD-1 targeting combination therapy.


2020 ◽  
Vol 8 (Suppl 2) ◽  
pp. A35.2-A36
Author(s):  
N Prokopi ◽  
CH Tripp ◽  
B Tummers ◽  
JC Crawford ◽  
M Efremova ◽  
...  

BackgroundImmunotherapy of cancer by checkpoint blockade has significantly improved the survival of melanoma patients. However, in patients with tumors that are poorly infiltrated by effector T cells the clinical results are not encouraging. Therefore, combination approaches that enhance pre-existing anti-tumor immunity and reset the patients‘ immunological status are urgently needed. In this study we used the tg(Grm1)EPv melanoma mouse model that reflects a non-immunogenic tumor microenvironment. In this mouse model, spontaneous melanoma development is driven by the ectopic expression of the metabotropic glutamate receptor-1 in melanocytes, which confers to them a hyperproliferative and anti-apoptotic phenotype. The same alteration has been shown to be present in 40% of melanoma patient samples. The aim of our study was to investigate whether enhancing dendritic cell (DC) numbers and function in the tg(Grm1)EPv mouse model could restore responsiveness to checkpoint blockade.Material and MethodsWe used multicolor flow cytometry, gene expression analysis by RNA-seq and microarray to analyze tumors and tumor-draining lymph nodes (tdLN). With various immunological in vitro and in vivo assays we determined the functional role of DC in tumor immunity.ResultsA loss of skin DC has previously been reported for primary melanoma lesions and we here show that melanoma progression in the tg(Grm1)EPv mouse model coincides with a gradual decrease in the skin cDC2 subset and an upregulation of the inhibitory ligands PD-L1 and galectin-9. Monotherapy with anti-PD-L1 could not delay tumor growth, suggesting that this is a good model to study resistance to checkpoint blockade. We hypothesized that by boosting DC numbers and function we would restore responsiveness to checkpoint blockade. By administering a treatment consisting of systemic Flt3L and intratumoral polyI:C/anti-CD40, we were able to rescue the numbers and function of skin cDC2. Analysis of the treated tumors by flow cytometry showed that the DC boost regimen led to an increased tumor infiltration of activated CD4+ and CD8+T cells. An in vitro T cell proliferation assay revealed that dermal cDC2 that had migrated to the tdLN, played a crucial role in this process, since these were able to cross-present endogenous gp100 antigen more efficiently than migratory Langerhans cells and dermal cDC1. CD4+ and CD8+T cells recruited in the tumors of the DC boost treated mice, expressed PD-1 and TIM-3. Therefore, combination therapy with checkpoint blockade of these molecules resulted in increased cytotoxic activity within the tumor and eventually delay of tumor growth.ConclusionsOur results demonstrate that skin DC shape the tumor microenvironment upon immunotherapy and thus, therapies that aim to enhance responsiveness to checkpoint blockade may well benefit from a component that boosts the numbers and the function of skin DC.Disclosure InformationN. Prokopi: None. C.H. Tripp: None. B. Tummers: None. J.C. Crawford: None. M. Efremova: None. K. Hutter: None. L. Bellmann: None. G. Cappellano: None. L. Boon: None. D. Ortner: None. Z. Trajanoski: None. S. Chen: None. T. de Gruijl: None. D.R. Green: None. P. Stoitzner: None.


Biomolecules ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 285 ◽  
Author(s):  
Ehexige Ehexige ◽  
Mingming Bao ◽  
Purevbat Bazarjav ◽  
Xiang Yu ◽  
Hai Xiao ◽  
...  

Cutaneous melanoma is the most aggressive skin cancer with notorious drug resistance. Inhibition of immune checkpoint molecules is one of the most promising approaches for cancer therapy. Herein, we show that RNAi mediated silencing of STAT3 expression in the tumor tissue robustly inhibit tumor growth in B16F10 mouse model of melanoma. We designed a peptidomimetic-based lipid nanoparticles (LNPs) for the delivery of siRNA in mouse model of melanoma. When systemically administered, the novel formulation (denote DoCh) preferentially delivered siRNA to the tumor tissue. Remarkably, sequential intravenous injections of siRNA against STAT3 induced profound silencing of STAT3 expression in tumor tissue, which resulted in significant downregulation of PD-L1, leading to significant inhibition of tumor growth through inhibition of tumor immune checkpoint. Moreover, DoCh-mediated siRNA delivery did not show noticeable damage to the major organs. Collectively, our data demonstrated that DoCh LNP is a promising tumor-targeted siRNA delivery system.


2021 ◽  
Author(s):  
Qian Shen ◽  
Lei Xu ◽  
Rong Li ◽  
Guang Wu ◽  
Senlin Li ◽  
...  

A robust TME pH-responsive nanoplatform was herein developed. This nanoplatform could significantly improve intracellular delivery of cytotoxic saporin to achieve an effective inhibition of tumor growth of breast cancer.


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