Smac mimetics synergize with immune checkpoint inhibitors to promote tumour immunity against glioblastoma

Abstract Small-molecule inhibitor of apoptosis (IAP) antagonists, called Smac mimetic compounds (SMCs), sensitize tumours to TNF-α-induced killing while simultaneously blocking TNF-α growth-promoting activities. SMCs also regulate several immunomodulatory properties within immune cells. We report that SMCs synergize with innate immune stimulants and immune checkpoint inhibitor biologics to produce durable cures in mouse models of glioblastoma in which single agent therapy is ineffective. The complementation of activities between these classes of therapeutics is dependent on cytotoxic T-cell activity and is associated with a reduction in immunosuppressive T-cells. Notably, the synergistic effect is dependent on type I IFN and TNF-α signalling. Furthermore, our results implicate an important role for TNF-α-producing cytotoxic T-cells in mediating the anti-cancer effects of immune checkpoint inhibitors when combined with SMCs. Overall, this combinatorial approach could be highly effective in clinical application as it allows for cooperative and complimentary mechanisms in the immune cell-mediated death of cancer cells.

Download Full-text

IMMU-06. COMBINATORIAL IMMUNE CHECKPOINT INHIBITORS FOR TARGETED INTRATUMORAL DELIVERY IN GBM

Neuro-Oncology ◽

10.1093/neuonc/noab196.366 ◽

2021 ◽

Vol 23 (Supplement_6) ◽

pp. vi93-vi93

Author(s):

Stephanie Sanders ◽

Denise Herpai ◽

Waldemar Debinski

Keyword(s):

T Cells ◽

Tumor Cells ◽

Immune Checkpoint ◽

Immune Checkpoint Inhibitors ◽

Checkpoint Inhibitors ◽

Cell Activity ◽

Live Cells ◽

Normal Brain ◽

Cytotoxic Therapies ◽

Checkpoint Receptors

Abstract Glioblastoma (GBM) is an immunologically cold tumor. Using single cell sequencing of CD45+ cells we confirmed that T cells are present within GBM samples. These T cells are positive for exhaustion markers such as LAG3 and TIGIT, as well as CTLA4 and PD1 checkpoint receptors. Modulating T cell activity through use of immune checkpoint inhibitors (ICIs) has shown efficacy in the treatment of a variety of solid tumors, and the combination of anti-CTLA4 and anti-PD1 ICIs has shown increased efficacy over use of a single therapeutic. Additionally, targeting ICIs to the tumor cells may increase efficacy of this treatment. We therefore constructed a combinatorial ICI redirected to GBM via interleukin 13 receptor alpha 2 (IL13RA2), a receptor over-expressed on the majority of GBM cells but not normal brain. The first component of the construct, labeled with a histidine tag, targets CTLA4 while the second component, tagged with a StrepII tag, targets PD1. The tags added to the constructs will allow for purification of a combinatorial heterodimer simultaneously targeting PD1, CTLA4 and IL13RA2. We purified individual components via fast protein liquid chromatography (FPLC) using a proteinG column followed by a HisTrap or StrepTrap column. We obtained a recombinant, targeted multivalent ICI at > 95% purity. We found that these constructs are able to bind their target receptors via ELISA in which the Kd values ranged from picomolar to low nanomolar range. Additionally, our constructs bind their target on live cells by flow cytometry. We next designed a heterodimeric construct which can combinatorially target CTLA4 and PD1 while also directing the ICI therapy to GBM. These constructs in conjunction with other immune stimulants like cytotoxic therapies are intended to facilitate the interaction between T cells and GBM tumor cells directly in a tumor microenvironment.

Download Full-text

Mechanisms of T-Cell Exhaustion in Pancreatic Cancer

Cancers ◽

10.3390/cancers12082274 ◽

2020 ◽

Vol 12 (8) ◽

pp. 2274

Author(s):

Didem Saka ◽

Muazzez Gökalp ◽

Betül Piyade ◽

Nedim Can Cevik ◽

Elif Arik Sever ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Immune Checkpoint ◽

Immune Checkpoint Inhibitors ◽

Checkpoint Inhibitors ◽

Critical Role ◽

Single Agent ◽

T Cell Exhaustion ◽

Inhibitory Receptors ◽

Cell Exhaustion

T-cell exhaustion is a phenomenon that represents the dysfunctional state of T cells in chronic infections and cancer and is closely associated with poor prognosis in many cancers. The endogenous T-cell immunity and genetically edited cell therapies (CAR-T) failed to prevent tumor immune evasion. The effector T-cell activity is perturbed by an imbalance between inhibitory and stimulatory signals causing a reprogramming in metabolism and the high levels of multiple inhibitory receptors like programmed cell death protein-1 (PD-1), cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), T cell immunoglobulin and mucin domain-containing protein 3 (TIM-3), and Lymphocyte-activation gene 3 (Lag-3). Despite the efforts to neutralize inhibitory receptors by a single agent or combinatorial immune checkpoint inhibitors to boost effector function, PDAC remains unresponsive to these therapies, suggesting that multiple molecular mechanisms play a role in stimulating the exhaustion state of tumor-infiltrating T cells. Recent studies utilizing transcriptomics, mass cytometry, and epigenomics revealed a critical role of Thymocyte selection-associated high mobility group box protein (TOX) genes and TOX-associated pathways, driving T-cell exhaustion in chronic infection and cancer. Here, we will review recently defined molecular, genetic, and cellular factors that drive T-cell exhaustion in PDAC. We will also discuss the effects of available immune checkpoint inhibitors and the latest clinical trials targeting various molecular factors mediating T-cell exhaustion in PDAC.

Download Full-text

Immune checkpoint and checkpoint inhibitors in hepatocellular carcinoma

Thai Journal of Hepatology ◽

10.30856/th.jhep2018vol1iss1_07 ◽

2018 ◽

Vol 1 (1) ◽

pp. 28-32

Author(s):

Piyawat Komolmit

Keyword(s):

Hepatocellular Carcinoma ◽

T Cells ◽

Major Histocompatibility Complex ◽

T Cell Receptor ◽

Immune Checkpoint ◽

Immune Checkpoint Inhibitors ◽

Checkpoint Inhibitors ◽

Cell Receptor ◽

Immune Checkpoints ◽

Histocompatibility Complex

การรักษามะเร็งด้วยแนวความคิดของการกระตุ้นให้ภูมิต้านทานของร่างกายไปทำลายเซลล์มะเร็งนั้น ปัจจุบันได้รับการพิสูจน์ชัดว่าวิธีการนี้สามารถหยุดยั้งการแพร่กระจายของเซลล์มะเร็ง โดยไม่ก่อให้เกิดภาวะแทรกซ้อนทางปฏิกิริยาภูมิต้านทานต่ออวัยวะส่วนอื่นที่รุนแรง สามารถนำมาใช้ทางคลินิกได้ ยุคของการรักษามะเร็งกำลังเปลี่ยนจากยุคของยาเคมีบำบัดเข้าสู่การรักษาด้วยภูมิต้านทาน หรือ immunotherapy ยากลุ่ม Immune checkpoint inhibitors โดยเฉพาะ PD-1 กับ CTLA-4 inhibitors จะเข้ามามีบทบาทในการรักษามะเร็งตับในระยะเวลาอันใกล้ จำเป็นแพทย์จะต้องมีความรู้ความเข้าใจในพื้นฐานของ immune checkpoints และยาที่ไปยับยั้งโมเลกุลเหล่านี้ Figure 1 เมื่อ T cells รับรู้แอนทิเจนผ่านทาง TCR/MHC จะมีปฏิกิริยาระหว่าง co-receptors หรือ immune checkpoints กับ ligands บน APCs หรือ เซลล์มะเร็ง ทั้งแบบกระตุ้น (co-stimulation) หรือยับยั้ง (co-inhibition) TCR = T cell receptor, MHC = major histocompatibility complex

Download Full-text

Inhibition of the PI3K/mTOR Pathway in Breast Cancer to Enhance Response to Immune Checkpoint Inhibitors in Breast Cancer

International Journal of Molecular Sciences ◽

10.3390/ijms22105207 ◽

2021 ◽

Vol 22 (10) ◽

pp. 5207

Author(s):

Chi Yan ◽

Jinming Yang ◽

Nabil Saleh ◽

Sheau-Chiann Chen ◽

Gregory D. Ayers ◽

...

Keyword(s):

Breast Cancer ◽

T Cells ◽

Tumor Growth ◽

Cd8 T Cells ◽

Immune Checkpoint ◽

Immune Checkpoint Inhibitors ◽

Checkpoint Inhibitors ◽

Mtor Pathway ◽

Complete Regression ◽

Mtor Inhibition

Objectives: Inhibition of the PI3K/mTOR pathway suppresses breast cancer (BC) growth, enhances anti-tumor immune responses, and works synergistically with immune checkpoint inhibitors (ICI). The objective here was to identify a subclass of PI3K inhibitors that, when combined with paclitaxel, is effective in enhancing response to ICI. Methods: C57BL/6 mice were orthotopically implanted with syngeneic luminal/triple-negative-like PyMT cells exhibiting high endogenous PI3K activity. Tumor growth in response to treatment with anti-PD-1 + anti-CTLA-4 (ICI), paclitaxel (PTX), and either the PI3Kα-specific inhibitor alpelisib, the pan-PI3K inhibitor copanlisib, or the broad spectrum PI3K/mTOR inhibitor gedatolisib was evaluated in reference to monotherapy or combinations of these therapies. Effects of these therapeutics on intratumoral immune populations were determined by multicolor FACS. Results: Treatment with alpelisib + PTX inhibited PyMT tumor growth and increased tumor-infiltrating granulocytes but did not significantly affect the number of tumor-infiltrating CD8+ T cells and did not synergize with ICI. Copanlisib + PTX + ICI significantly inhibited PyMT growth and increased activation of intratumoral CD8+ T cells as compared to ICI alone, yet did not inhibit tumor growth more than ICI alone. In contrast, gedatolisib + ICI resulted in significantly greater inhibition of tumor growth compared to ICI alone and induced durable dendritic-cell, CD8+ T-cell, and NK-cell responses. Adding PTX to this regimen yielded complete regression in 60% of tumors. Conclusion: PI3K/mTOR inhibition plus PTX heightens response to ICI and may provide a viable therapeutic approach for treatment of metastatic BC.

Download Full-text

Abstract 1666: Tumor-specificity of tumor-infiltrating CD8+ t cells determines the potential of immune checkpoint inhibitors in breast cancer

10.1158/1538-7445.am2021-1666 ◽

2021 ◽

Author(s):

Jee Ye Kim ◽

Yong Joon Lee ◽

Seung hyuck Jeon ◽

Heejin Nam ◽

Jae Hyung Jung ◽

...

Keyword(s):

Breast Cancer ◽

T Cells ◽

Cd8 T Cells ◽

Immune Checkpoint ◽

Immune Checkpoint Inhibitors ◽

Checkpoint Inhibitors ◽

Tumor Specificity

Download Full-text

540 Baseline mTOR transcriptional signatures in CD8 T cells are associated with immune-related adverse events but not anti-tumor responses in patients receiving immune checkpoint inhibitors

Journal for ImmunoTherapy of Cancer ◽

10.1136/jitc-2021-sitc2021.540 ◽

2021 ◽

Vol 9 (Suppl 3) ◽

pp. A570-A570

Author(s):

Chen Zhao ◽

Matthew Mule ◽

Andrew Martins ◽

Iago Pinal Fernandez ◽

Renee Donahue ◽

...

Keyword(s):

T Cells ◽

Adverse Events ◽

Tumor Immunity ◽

Cd8 T Cells ◽

Immune Checkpoint ◽

Immune Checkpoint Inhibitors ◽

Checkpoint Inhibitors ◽

Effector Memory ◽

Link Type ◽

Anti Tumor Activity

BackgroundImmune checkpoint inhibitors (ICIs) have changed the cancer treatment landscape, but immune-related adverse events (irAEs) can affect a wide range of tissues in patients receiving ICIs. Severe irAEs can be life-threatening or fatal and prohibit patients from receiving further ICI treatment. While the clinical features of irAEs are well documented, the pathological mechanisms and predictive biomarkers are largely unknown. In addition, there is a critical need to preserve ICI-induced anti-tumor immunity while controlling for irAEs, which requires deciphering molecular and cellular signatures associated specifically with irAEs beyond those more generally linked to anti-tumor immunity.MethodsTo unbiasedly identify immune cells and states associated with irAEs, we applied CITE-seq to measure transcripts and surface proteins (83 protein markers) from PBMCs collected from patients with thymic epithelial tumors before and after treatment with an anti-PD-L1 antibody (avelumab, NCT01772004, NCT03076554).ResultsSamples from 9 patients were analyzed. No patient had a history of pre-existing paraneoplastic autoimmune disease. Anti-tumor activity was observed in all cases, and 5 patients had clinical and/or biochemical evidence of immune-related muscle inflammation (myositis with or without myocarditis). Multilevel models applied within highly resolved cell clusters revealed transcriptional states associated with ICI response and more uniquely with irAEs. A total of 190,000 cells were included in the analysis after quality control. Most notably, CD45RA+ effector memory CD8 T cells with an mTOR transcriptional signature were highly enriched at baseline and post treatment in patients with irAEs.ConclusionsOur findings suggest the potential therapeutic avenues by using mTOR inhibitors to dampen autoimmune responses while potentially sparing anti-tumor activity, to prevent treatment discontinuation and improve clinical outcomes for cancer patients treated with ICIs.AcknowledgementsThis research was supported in part by the Intramural Research Program of the NCI (the Center for Cancer Research), NIAID and NIAMS, and through a Cooperative Research and Development Agreement between the National Cancer Institute and EMD Serono.Trial RegistrationNCT01772004, NCT03076554Ethics ApprovalThis study is approved by NCI institutional review board.

Download Full-text

Combinatorial benefit without synergy in recent clinical trials of immune checkpoint inhibitors

10.1101/2020.01.31.20019604 ◽

2020 ◽

Cited By ~ 1

Author(s):

Adam C. Palmer ◽

Benjamin Izar ◽

Peter K. Sorger

Keyword(s):

Clinical Trials ◽

Immune Checkpoint ◽

Immune Checkpoint Inhibitors ◽

Checkpoint Inhibitors ◽

Single Agent ◽

Combination Therapies ◽

Anti Tumor Activity

ABSTRACTHundreds of clinical trials are testing whether combination therapies can increase the anti-tumor activity of Immune Checkpoint Inhibitors (ICIs). We find that the benefits of recently reported and approved combinations involving ICIs are fully accounted for by increasing the chance of a single-agent response (drug independence), with no requirement for additive or synergistic efficacy. Thus, the degree of success of combinations involving ICIs with other therapies is largely predictable.

Download Full-text

Review of Indications of FDA-Approved Immune Checkpoint Inhibitors per NCCN Guidelines with the Level of Evidence

Cancers ◽

10.3390/cancers12030738 ◽

2020 ◽

Vol 12 (3) ◽

pp. 738 ◽

Cited By ~ 73

Author(s):

Raju K. Vaddepally ◽

Prakash Kharel ◽

Ramesh Pandey ◽

Rohan Garje ◽

Abhinav B. Chandra

Keyword(s):

T Cells ◽

T Cell ◽

Immune Checkpoint ◽

Immune Checkpoint Inhibitors ◽

Molecular Mechanisms ◽

Checkpoint Inhibitors ◽

Hematopoietic Cells ◽

Fda Approval ◽

Programmed Death ◽

Cancerous Cells

Cancer is associated with higher morbidity and mortality and is the second leading cause of death in the US. Further, in some nations, cancer has overtaken heart disease as the leading cause of mortality. Identification of molecular mechanisms by which cancerous cells evade T cell-mediated cytotoxic damage has led to the modern era of immunotherapy in cancer treatment. Agents that release these immune brakes have shown activity to recover dysfunctional T cells and regress various cancer. Both cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) and Programmed Death-1 (PD-1) play their role as physiologic brakes on unrestrained cytotoxic T effector function. CTLA-4 (CD 152) is a B7/CD28 family; it mediates immunosuppression by indirectly diminishing signaling through the co-stimulatory receptor CD28. Ipilimumab is the first and only FDA-approved CTLA-4 inhibitor; PD-1 is an inhibitory transmembrane protein expressed on T cells, B cells, Natural Killer cells (NKs), and Myeloid-Derived Suppressor Cells (MDSCs). Programmed Death-Ligand 1 (PD-L1) is expressed on the surface of multiple tissue types, including many tumor cells and hematopoietic cells. PD-L2 is more restricted to hematopoietic cells. Blockade of the PD-1 /PDL-1 pathway can enhance anti-tumor T cell reactivity and promotes immune control over the cancerous cells. Since the FDA approval of ipilimumab (human IgG1 k anti-CTLA-4 monoclonal antibody) in 2011, six more immune checkpoint inhibitors (ICIs) have been approved for cancer therapy. PD-1 inhibitors nivolumab, pembrolizumab, cemiplimab and PD-L1 inhibitors atezolizumab, avelumab, and durvalumab are in the current list of the approved agents in addition to ipilimumab. In this review paper, we discuss the role of each immune checkpoint inhibitor (ICI), the landmark trials which led to their FDA approval, and the strength of the evidence per National Comprehensive Cancer Network (NCCN), which is broadly utilized by medical oncologists and hematologists in their daily practice.

Download Full-text

Efficacy of immune checkpoint inhibitors for in-transit melanoma

Journal for ImmunoTherapy of Cancer ◽

10.1136/jitc-2019-000440 ◽

2020 ◽

Vol 8 (1) ◽

pp. e000440 ◽

Cited By ~ 1

Author(s):

Emilia Nan Tie ◽

Julia Lai-Kwon ◽

Michael Alexander Rtshiladze ◽

Lumine Na ◽

James Bozzi ◽

...

Keyword(s):

Immune Checkpoint ◽

Immune Checkpoint Inhibitors ◽

Checkpoint Inhibitors ◽

Single Agent ◽

Progression Free Survival ◽

Distant Metastases ◽

Mek Inhibitor ◽

Disease Recurrence ◽

In Transit

BackgroundThe efficacy of immune checkpoint inhibitors (ICI) in metastatic melanoma is well established. However, there are limited data regarding their efficacy in in-transit melanoma (ITM). This study assessed the efficacy of ICI in patients with ITM.MethodsA retrospective review of patients with ITM commenced on an ICI between March 2013 and February 2018 at three tertiary centers in Australia. Patients were excluded if they had previous or synchronous distant metastases. Overall response rate (ORR), progression-free survival (PFS) and overall survival (OS) were based on a composite of radiological and clinical assessments.ResultsFifty-four patients were included: 27 (50%) female; median age 75 (range 26–94); 12 (22%) stage IIIB, 40 (74%) stage IIIC and 2 (4%) stage IIID; 10 (19%) BRAF mutant. Forty (74%) received single-agent anti-PD-1 (pembrolizumab or nivolumab), 8 (15%) single agent anti-CTLA-4 (ipilimumab), 5 (9%) combination anti-PD-1/anti-CTLA-4 (ipilimumab and nivolumab or pembrolizumab) and 1 (2%) combination anti-PD-L1 (atezolizumab) and MEK inhibitor (cobimetinib). The median follow-up was 15 months (2–46).ORR to ICI was 54%: 14 (26%) complete responses; 15 (28%) partial responses; 9 (17%) stable disease; 16 (30%) progressive disease. Thirteen (46%) responders had only one ITM lesion. ORR was 58% for single-agent anti-PD-1, 38% for single-agent anti-CTLA4 and 40% for anti-PD-1/anti-CTLA-4. The median PFS was 11.7 months (6.6-not reached). 1-year and 2-year PFS were 48% and 39%, respectively,. Fourteen progressed locoregionally and 11 progressed distantly. The median OS was not reached. 1-year and 2-year OS were 85% and 63%, respectively. No clinicopathological features were associated with ORR.Conclusions and relevanceICI produce objective responses in ITM and should be considered in patients with unresectable ITM or disease recurrence.

Download Full-text