All times are listed in CEST (Central European Summer Time)
4MO - Preclinical evaluation of novel CDK4/6 inhibitor GLR2007 in breast and lung cancer models
- Lei Yin (Beijing, China)
Abstract
Background
Cyclin-dependent kinases (CDKs) such as CDK4/6 are essential in regulating the cell cycle, which is disrupted in many cancers. Currently marketed CDK4/6 inhibitors abemaciclib, palbociclib, and ribociclib have shown preclinical efficacy in solid tumors including breast cancer and non-small cell lung cancer. GLR2007 is an investigational CDK4/6 inhibitor with potential to treat advanced solid tumors.
Methods
Results
GLR2007 inhibited proliferation at lower IC50 values compared to abemaciclib in 5 breast cancer cell lines (IC50 fold difference range = 0.08–0.92; median = 0.33) and in 20 lung cancer cell lines (IC50 fold difference range = 0.03–0.99; median = 0.39). In MCF-7 breast cancer orthotopic xenografts, compared to vehicle control, 50 mg/kg GLR2007 induced 49.6% tumor growth inhibition (TGI) (
Conclusions
In a number of tumor cell lines, GLR2007 inhibited proliferation at lower IC50 values compared to abemaciclib. GLR2007 demonstrated significant antitumor efficacy in xenograft models compared to vehicle controls. These preclinical studies demonstrate the potential of GLR2007 as a novel CDK4/6 inhibitor for the treatment of breast and lung cancer.
Editorial acknowledgement
The authors acknowledge Derah Saward-Arav, PhD, of Integrated Medhealth Communication (IMC), UK, for medical writing support.
Legal entity responsible for the study
Gan & Lee Pharmaceuticals.
Funding
Gan & Lee Pharmaceuticals.
Disclosure
L. Yin, Z. Yao, A. Yin: Financial Interests, Personal, Full or part-time Employment: Gan & Lee Pharmaceuticals. Y. Wang, Y. Huang, M. Mazuranic: Financial Interests, Personal, Full or part-time Employment: Gan & Lee Pharmaceuticals USA Corp.
5MO - CDK4/6 blockade is as effective as immune-checkpoint inhibition in tumor growth control of Mlh1-/- and Msh2loxP/loxP villin-Cre mice
- Inken Salewski (Rostock, Germany)
Abstract
Background
Mismatch-repair deficiency (dMMR) is a hallmark of Lynch syndrome-associated cancers, often resulting from inactivating mutations in
Methods
In this ongoing trial, Mlh1-/- or Msh2loxP/loxP Villin-Cre mice with gastrointestinal tumors were either treated with anti-PD-L1 monoclonal antibody (clone: 6E11, 2.5 mg/kg bw, i.p., q2wx3) or abemaciclib (75 mg/kg bw, p.o.,q1wx8). Control mice received the isotype (anti-IgG1 2.5 mg/kg bw, i.p., q2wx3) or were left untreated. Blood phenotyping was performed regularly. The tumor microenvironment was studied by immunofluorescence.
Results
Both therapies prolonged overall survival of mice significantly: Mlh1-/-: 9.1 wks (6E11) vs. 11.1 wks (abemaciclib) vs. 3.5 wks (control);
Conclusions
While ICI-based therapies are effective and FDA approved for dMMR cancer, abemaciclib constitutes a promising alternative therapy option. The strong immune stimulation upon abemaciclib treatment renders this compound ideal for ICI-refractory or intrinsically resistant tumors.
Legal entity responsible for the study
The authors.
Funding
German Research Foundation.
Disclosure
All authors have declared no conflicts of interest.
6MO - PCSK9 inhibitor evolocumab reduces cardiotoxicity and inflammation induced by doxorubicin-trastuzumab sequential treatment through MyD88/NF-kB/mTORC1 pathways
- Vincenzo Quagliariello (Napoli, Italy)
Abstract
Background
Inhibition of proprotein convertase subtilisin/kexin type 9 (PCSK9) has emerged as a novel therapy to treat hypercholesterolaemia and related cardiovascular diseases. Evolocumab, a PCSK9 inhibitor, reduced the risk of cardiovascular events in patients with atherosclerotic cardiovascular diseases when added to maximally tolerated statin therapy (± ezetimibe), and recent data from the ODYSSEY OUTCOMES trial indicate that alirocumab added to maximally tolerated statin therapy (± other lipid-lowering drugs) reduces the risk of cardiovascular events in patients with a recent acute coronary syndrome.
Methods
Human fetal cardiomyocytes (HFC cell line) were exposed to subclinical concentration of doxorubicin, trastuzumab, sequential treatment of both (all 100 nM), alone or in combination with evolocumab (50 nM) for 48h. After the incubation period, we performed the following tests: determination of cell viability, through analysis of mitochondrial dehydrogenase activity, study of lipid peroxidation (quantifying cellular Malondialdehyde and 4-hydroxynonenal), intracellular Ca2+ homeostasis. Moreover, pro-inflammatory studied were also performed (activation of NLRP3 inflammasome; expression of TLR4/MyD88; mTORC1 Fox01/3a; transcriptional activation of p65/NF-κB and secretion of cytokines involved in cardiotoxicity (Interleukins 1β, 8, 6).
Results
Evolocumab co-incubated with doxorubicin alone or in sequence with trastuzumab exerts cardioprotective effects, enhancing cell viability of 35-43% compared to untreated cells (p<0,05 for all); Evolocumab reduced significantly the cardiotoxicity through MyD88/NF-KB/cytokines axis and mTORC1 Fox01/3α mediated mechanisms.
Conclusions
We demonstrated, for the first time, that the PCSK9 inhibitor evolocumab exerts direct effects in cardiomyocytes during doxorubicin and trastuzumab exposure turning on a new light on its possible use in cancer patients.
Legal entity responsible for the study
The authors.
Funding
Ministero della Salute, Italy.
Disclosure
All authors have declared no conflicts of interest.
Discussion 4MO, 5MO and 6MO
- Ruth Plummer (Newcastle-upon-Tyne, Tyne and Wear, United Kingdom)
7MO - Effect of anti-CTLA-4 immunotherapy on lymphocyte subset and activation profiles and clonal composition on the B16F0 mouse melanoma model
- Diana V. Yuzhakova (Nizhny Novgorod, Russian Federation)
Abstract
Background
One of most promising strategies for cancer immunotherapy is immune checkpoint blockade. However, the remarkable responses to the therapy are currently limited to a minority of patients and indications, highlighting the importance of understanding of immune mechanisms. The purpose of this study was to investigate the effect of anti-CTLA-4 immunotherapy on lymphocyte subset and activation profiles and clonal composition on the B16F0 mouse melanoma model.
Methods
The experiments were carried out on C57BL/6 mice bearing B16F0 mouse melanoma. Mice were treated with 250 μg anti-CTLA4 (Bio X Cell, USA). T-lymphocytes were obtained from tumor or lymphatic nodules (LN), analyzed by flow cytometry using a FACSAria III cell sorter, sorted and evaluated by RNA- and TCR (T cell receptor)-seq.
Results
We identified that Th СD4 subset appeared to be primary target of CTLA-4 therapy. The effect consisted of increased ratio of Th/CD8 and skew of Th cells from IFNγ-secreting towards proliferating cells within the tumor. Analysis of major lymphocyte subsets from LN revealed an increased percentage of activated CD69+/CD25+ cells from Th, CD8+ and B cells and IFNγ+ secretion by Th. We found that the number of TCR clusters significantly increased in Th after therapy. This indicates proliferation of certain Th clones, yet with unknown specificities. To identify the antigen specificity of these clones we immunized mice with melanoma peptide neoantigens and harvested T-cells from LN. Then T-cells were cocultured with APCs loaded with different melanoma peptides. We identified up to 75% CD69+/CD25+ activated T-cells to the specific peptides. We detected clones of TCR, which were found with a high frequency in cells reactivated to specific peptides and were not found in the control. Now the data set is in progress. Future experiments will be directed to compare B16F0-specific TCRs with proliferative clones after anti-CTLA4 blockade.
Conclusions
We found that anti-CTLA-4 immunotherapy leads to activation and clonal expansion of lymphocytes with similar TCRs. For detailed analysis, we developed the approach to identify the TCR specificity to specific B16F0 peptides.
Legal entity responsible for the study
The authors.
Funding
Ministry of Science and Higher Education of the Russian Federation (grant # 14.W03.31.0005).
Disclosure
All authors have declared no conflicts of interest.
1801MO - Neutrophils are associated with resistance to anti-PD-1 monotherapy in mismatch repair-deficient tumors
- Laetitia Nebot (Villejuif, Cedex, France)
Abstract
Background
Clinical studies have highlighted the efficacy of anti-PD-1 (αPD-1) treatment in patients with hypermutated tumors deficient in DNA mismatch repair (MMRD). However, the responsiveness of MMRD tumors to αPD-1 treatment is variable, and the cause to explain this variability remains unclear.
Methods
Two mouse tumor cell lines inactivated for
Results
While αPD-1 treatment was effective in the CT26MSH2-/- model, no efficacy was observed in the 4T1MSH2-/- even in ultra-mutated 4T1MSH2-/- tumors (>280 mutations/Megabase). Unlike the CT26 model, 4T1 model is characterized by an accumulation of neutrophils. Neutrophils depletion with αPD-1 or the combination αPD-1+αCTLA-4 restored the response to immunotherapy in 4T1MSH2-/- model. Given that the combination treatment was accompanied by a decrease in neutrophils, it is likely that CTLA-4 blockade may hamper the accumulation of neutrophils. Consistent with this, we calculated the percentage of the NLR variation between baseline and two months after anti-PD-(L)1 initiation in 104 patients. Median overall survival was undefined for %NLRvariation <0% and 23.13 months for patients with %NLRvariation >0% (HRlogrank=0.40; 95%IC: 0.18-0.91).
Conclusions
Accumulation of neutrophils is associated with resistance to αPD-1 monotherapy in MMRD tumors. We propose that αPD-1+αCTLA-4 combination may represent an effective strategy in patients with abnormal neutrophil accumulation.
Legal entity responsible for the study
The authors.
Funding
CNRS, INSERM, La Ligue Nationale Contre le Cancer.
Disclosure
All authors have declared no conflicts of interest.
1802MO - Influence of preoperative chemoradiation on tumor-infiltrating lymphocytes in locally advanced rectal cancer: The STAR-01 cohort
- Letizia Gnetti (Parma, Italy)
Abstract
Background
Preoperative chemoradiotherapy (CRT) may increase antitumor immunity through enhancing T-cell activation and tumor infiltration. These effects could possibly sensitize tumours to immunotherapies, including checkpoint inhibitors. We explored whether preoperative CRT for locally advanced rectal cancer (LARC) induces immunologic changes and if the post-operative biological parameters are associated with tumour regression grade (TRG sec. Ryan –AJCC Eight ed.).
Methods
The multicenter randomized STAR-01 study compared a standard preoperative CRT regimen (50.4 Gy in 28 daily fractions with concomitant infused fluorouracil at the dose of 225 mg/m2/d) with the same regimen plus oxaliplatin given weekly at the dose of 60 mg/m2 in patients with LARC. Paired pre- and post-operative specimens were available for 81 patients and were analyzed by immunohistochemistry. The immunoistochemical analysis was performed with a panel of immune cells and associated factors as CD3, CD20, CD4/CD8, PD1. The pattern of tumor infiltrating lymphocytes (TILs) and related infiltrating lymphocytes (RILs) was also evaluated. Response to pre-operative chemoradiotherapy was assessed according to TRG.
Results
After therapy we observed a decreased CD4/CD8 ratio (p <0.001) and reduced expression level of CD20 (p<0.001). The expression level of CD3+ and PD-1+ cells after therapy did not change significantly. The relative increase of lymphocytes CD8+ inside CD4/CD8 ratio evaluated on post-operative samples was significantly associated with TRG 0 (p<0.001).
Conclusions
Our data suggest that CRT may induce an enrichment of CD8+ T lymphocytes and this translates in better response to CRT. The new frontier of best treatment could be the use of specific immune cells (T lymphocytes) to trigger the system's immune response against disease.
Legal entity responsible for the study
University Hospital of Parma.
Funding
SNUPI ONLUS.
Disclosure
All authors have declared no conflicts of interest.
Discussion 7MO, 1801MO and 1802MO
- Christian H. Ottensmeier (Liverpool, United Kingdom)