T cell Bim levels reflect responses to anti-PD-1 cancer therapy

New insights into the function and pathophysiology of the ectodomain sheddase A Disintegrin And Metalloproteinase 10 (ADAM10)

The 'A Disintegrin And Metalloproteinase 10' (ADAM10) has gained considerable attention due to its discovery as an 'α-secretase' involved in the nonamyloidogenic processing of the amyloid precursor protein, thereby possibly preventing the excessive generation of the amyloid beta peptide, which is associated with the pathogenesis of Alzheimer's disease. ADAM10 was found to exert many additional functions, cleaving about 100 different membrane proteins. ADAM10 is involved in many pathophysiological conditions, ranging from cancer and autoimmune disorders to neurodegeneration and inflammation. ADAM10 cleaves its substrates close to the plasma membrane, a process referred to as ectodomain shedding. This is a central step in the modulation of the functions of cell adhesion proteins and cell surface receptors. ADAM10 activity is controlled by transcriptional and post-translational events. The interaction of ADAM10 with tetraspanins and the way they functionally and structurally depend on each other is another topic of interest. In this review, we will summarize findings on how ADAM10 is regulated and what is known about the biology of the protease. We will focus on novel aspects of the molecular biology and pathophysiology of ADAM10 that were previously poorly covered, such as the role of ADAM10 on extracellular vesicles, its contribution to virus entry, and its involvement in cardiac disease, cancer, inflammation, and immune regulation. ADAM10 has emerged as a regulator controlling cell surface proteins during development and in adult life. Its involvement in disease states suggests that ADAM10 may be exploited as a therapeutic target to treat conditions associated with a dysfunctional proteolytic activity.

MCL1 inhibition targets Myeloid Derived Suppressors Cells, promotes antitumor immunity and enhances the efficacy of immune checkpoint blockade

Immune checkpoint inhibitors (ICIs) are now the first-line treatment for patients with advanced melanoma. Despite promising clinical results, many patients fail to respond to these therapies. BH3 mimetics, a novel class of small molecule inhibitors that bind and inhibit anti-apoptotic members of the BCL2 family proteins such as BCL2 or MCL1, have been very successful in treating hematologic malignancies. However, there are limited studies on the immunomodulatory role of the BH3 mimetics. Several factors contribute to ICI resistance including myeloid-derived suppressor cells (MDSCs) that exert immunosuppressive effects through direct and indirect inhibition of antitumor immunity. Thus, targeting MDSCs to enhance antitumor immunity has the potential to enhance the efficacy of ICIs. In this study, we show that the MCL1 inhibitor S64315 reduces melanoma tumor growth in an immune cell-dependent manner in mice. Specifically, S64315 enhances antitumor immunity by reducing MDSC frequency and by promoting the activity of CD8+T cells. Additionally, human MDSCs are 10 times more sensitive to S64315 than cutaneous melanoma lines. Further, we found that a higher expression of MCL1 is associated with poor survival for patients treated with anti-PD-1. Finally, combining S64315 and anti-PD-1 significantly slowed tumor growth compared to either agent alone. Together, this proof-of-concept study demonstrates the potential of combining an MCL1 inhibitor with anti-PD-1 in the treatment of melanoma. It justifies the further development of next generation MCL1 inhibitors to improve efficacy of ICIs in treating malignant melanoma.

Circulating antigen-primed cytotoxic T-cells in patients with renal tumors treated with surgery

INTRODUCTION

Systemic immunotherapy has changed the paradigm of treatment of advanced renal cell carcinoma, but nephrectomy continues to benefit selected patients. While we continue to identify mechanisms behind drug resistance, the effect of surgery on natural anti-tumor immunity is poorly understood. Specifically, peripheral blood mononuclear cell (PBMC) profile and tumor reactive cytotoxic T lymphocytes changes secondary to tumor resection have not been extensively characterized. Hence, we aimed to evaluate the effect of nephrectomy on PMBC profile and circulating antigen-primed CD8+ T-cells for patients undergoing solid renal mass resection.

METHODS

Patients with localized or metastatic solid renal masses who underwent nephrectomy from 2016 to 2018 were enrolled. Blood samples were collected at 3 timepoints for PBMCs analysis (pre-op, 1 day, and 3 months post-op). Flow cytometry was used to identify CD11ahigh CD8+ T lymphocytes that were then further characterized according to the expression of CX3CR1/GZMB, Ki67, Bim, and PD-1. Changes in circulating CD8+ T-cells from pre-op to 1 day and 3 months post-op were evaluated using Wilcoxon signed rank tests.

RESULTS

Antigen-primed CX3CR1+GZMB+ T-cells significantly increased by 3 months after surgery among patients with RCC (0.8 × 109 cells; P = 0.01). In contrast, there was a decrease in absolute numbers of Bim+ T-cells at 3 months (-1.9 × 109 cells; P = 0.02). There were no significant absolute changes in PD-1+ (-1.4 × 109; P = 0.7) and CD11ahigh CD8+ T lymphocytes (1.3 × 109; P = 0.9). Ki67+ T-cells decreased by 3 months (-0.8 × 109; P < 0.001).

CONCLUSIONS

Nephrectomy is associated with an increase in cytolytic antigen-primed CD8+ T-cells and specific PBMC profile changes. Further studies are warranted to ascertain the role surgery may have in the restoration of anti-tumor immunity.

Peripheral CD4 memory T cells predict the efficacy of immune checkpoint inhibitor therapy in patients with non-small cell lung cancer

Immune checkpoint inhibitors have significantly improved the prognosis in patients with non-small cell lung cancer, compared with cytotoxic agents. However, the prediction of treatment response is often difficult, even after assessing the tumor programmed death-ligand 1 expression. We conducted this observational study to analyze the association between the differentiation of peripheral CD4 + T cells and the efficacy of immune checkpoint inhibitor therapy. We enrolled patients who were diagnosed with non-small cell lung cancer and received immune checkpoint inhibitor therapy between 2020 and 2022. Blood samples were collected at the start of immune checkpoint inhibitor therapy, and the expressions of PD-1, CCR7, and CD45RA in peripheral CD4 + T cells were analyzed by flow cytometry. The association between the findings of flow cytometry and survival after the initiation of the immune checkpoint inhibitor therapy was evaluated. Forty patients with non-small cell lung cancer were enrolled. The Cox proportional hazards model showed that an increased proportion of CD45RA-CD4 + T cells was associated with a reduced risk of progression after adjustment for performance status, tumor programmed death-ligand 1 expression level, mutation status of the epidermal growth factor receptor gene, and combined therapy with cytotoxic agents. The present study showed that the proportion of peripheral CD45RA- CD4 + T cells was associated with progression-free survival after the initiation of immune checkpoint inhibitor therapy, independent of several clinical factors.

BCL2L11 Induction Mediates Sensitivity to Src and MEK1/2 Inhibition in Thyroid Cancer

Patients with advanced thyroid cancer, including advanced papillary thyroid cancer and anaplastic thyroid cancer (ATC), have low survival rates because of the lack of efficient therapies available that can combat their aggressiveness. A total of 90% of thyroid cancers have identifiable driver mutations, which often are components of the MAPK pathway, including BRAF, RAS, and RET-fusions. In addition, Src is a non-receptor tyrosine kinase that is overexpressed and activated in thyroid cancer, which we and others have shown is a clinically relevant target. We have previously demonstrated that combined inhibition of Src with dasatinib and the MAPK pathway with trametinib synergistically inhibits growth and induces apoptosis in BRAF- and RAS-mutant thyroid cancer cells. Herein, we identified the pro-apoptotic protein BCL2L11 (BIM) as being a key mediator of sensitivity in response to combined dasatinib and trametinib treatment. Specifically, cells that are sensitive to combined dasatinib and trametinib treatment have inhibition of FAK/Src, MEK/ERK, and AKT, resulting in the dramatic upregulation of BIM, while cells that are resistant lack inhibition of AKT and have a dampened induction of BIM. Inhibition of AKT directly sensitizes resistant cells to combined dasatinib and trametinib but will not be clinically feasible. Importantly, targeting BCL-XL with the BH3-mimeitc ABT-263 is sufficient to overcome lack of BIM induction and sensitize resistant cells to combined dasatinib and trametinib treatment. This study provides evidence that combined Src and MEK1/2 inhibition is a promising therapeutic option for patients with advanced thyroid cancer and identifies BIM induction as a potential biomarker of response.

Tumor-Derived Extracellular Vesicles Predict Clinical Outcomes in Oligometastatic Prostate Cancer and Suppress Antitumor Immunity

PURPOSE

SABR has demonstrated clinical benefit in oligometastatic prostate cancer. However, the risk of developing new distant metastatic lesions remains high, and only a minority of patients experience durable progression-free response. Therefore, there is a critical need to identify which patients will benefit from SABR alone versus combination SABR and systemic agents. Herein we provide, to our knowledge, the first proof-of-concept of circulating prostate cancer-specific extracellular vesicles (PCEVs) as a noninvasive predictor of outcomes in oligometastatic castration-resistant prostate cancer (omCRPC) treated with SABR.

METHODS AND MATERIALS

We analyzed the levels and kinetics of PCEVs in the peripheral blood of 79 patients with omCRPC at baseline and days 1, 7, and 14 after SABR using nanoscale flow cytometry and compared with baseline values from cohorts with localized and widely metastatic prostate cancer. The association of omCRPC PCEV levels with oncological outcomes was determined with Cox regression models.

RESULTS

Levels of PCEVs were highest in mCRPC followed by omCRPC and were lowest in localized prostate cancer. High PCEV levels at baseline predicted a shorter median time to distant recurrence (3.5 vs 6.6 months; P = .0087). After SABR, PCEV levels peaked on day 7, and median overall survival was significantly longer in patients with elevated PCEV levels (32.7 vs 27.6 months; P = .003). This suggests that pretreatment PCEV levels reflect tumor burden, whereas early changes in PCEV levels after treatment predict response to SABR. In contrast, radiomic features of ¹¹C-choline positron emission tomography and computed tomography before and after SABR were not predictive of clinical outcomes. Interestingly, PCEV levels and peripheral tumor-reactive CD8 T cells (T_TR; CD8⁺ CD11a^high) were correlated.

CONCLUSIONS

This original study demonstrates that circulating PCEVs can serve as prognostic and predictive markers to SABR to identify patients with "true" omCRPC. In addition, it provides novel insights into the global crosstalk, mediated by PCEVs, between tumors and immune cells that leads to systemic suppression of immunity against CRPC. This work lays the foundation for future studies to investigate the underpinnings of metastatic progression and provide new therapeutic targets (eg, PCEVs) to improve SABR efficacy and clinical outcomes in treatment-resistant CRPC.

Pathological complete response to neoadjuvant chemoimmunotherapy correlates with peripheral blood immune cell subsets and metastatic status of mediastinal lymph nodes (N2 lymph nodes) in non-small cell lung cancer

BACKGROUND

Neoadjuvant chemo-immunotherapy has got clinical benefits in parts of resectable non-small cell lung cancer (NSCLC) patients. The factors affecting the pathological response of NSCLC remain controversial.

METHODS

A retrospective study of 59 patients with resectable stage IIA-IIIB NSCLC who were treated with neoadjuvant chemo-immunotherapy was performed. The clinical characteristics were analyzed in the pathological complete response (pCR) group and the non-pCR group. The immune cell subsets in peripheral blood were detected by flow cytometry.

RESULTS

By analyzing the correlation between pathological response and clinical characteristics, we found that patients with N2 metastases were less effective in neoadjuvant chemo-immunotherapy (P = 0.001). Programmed death-ligand 1 (PD-L1) expression and treatment cycle were not related to pathological response (P > 0.05). Lower levels of total T cells, Th cells, and higher levels of NK cells in baseline were associated with pCR (P < 0.05). And during neoadjuvant chemo-immunotherapy, total T cells and activated T cells were significantly increased in patients with pCR (P < 0.05).

CONCLUSION

The peripheral blood immune cell subsets and lymph node status were closely related to pathological response in patients with neoadjuvant chemo-immunotherapy. No significant correlation was found between pathologic response and PD-L1 expression.

Clinical outcome following checkpoint therapy in renal cell carcinoma is associated with a burst of activated CD8 T cells in blood

PURPOSE

Checkpoint therapy is now the cornerstone of treatment for patients with renal cell carcinoma (RCC) with advanced disease, but biomarkers are lacking to predict which patients will benefit. This study proposes potential immunological biomarkers that could developed for predicting therapeutic response in patients with RCC.

METHODS

Using flow cytometry, RNA sequencing, and T-cell receptor (TCR) sequencing, we investigated changes in T cells in the peripheral blood of patients with advanced RCC after receiving immunotherapy. We used immunofluorescence (IF) imaging and flow cytometry to investigate how intratumoral T cells in patients' tumors (resected months/years prior to receiving checkpoint therapy) predicted patient outcomes after immunotherapy.

RESULTS

We found that a small proportion of CD4 and CD8 T cells in the blood activate following checkpoint therapy, expressing the proliferation marker Ki67 and activation markers HLA-DR and CD38. Patients who had the highest increase in these HLA-DR +CD38+CD8 T cells after treatment had the best antitumor immune response and experienced clinical benefit. Using RNA sequencing, we found that while these cells expanded in most patients, their phenotype did not drastically change during treatment. However, when we analyzed the TCR repertoire of these HLA-DR +CD38+CD8+T cells, we found that only patients who clinically benefitted had a burst of new clonotypes enter this pool of activated cells. Finally, we found that abundant T cells in the untreated tumors predicted clinical benefit to checkpoint therapy on disease progression.

CONCLUSIONS

Together, these data suggest that having a strong pre-existing immune response and immediate peripheral T-cell activation after checkpoint therapy is a predictor of clinical benefit in patients with RCC.

Understanding Suboptimal Response to Immune Checkpoint Inhibitors

Immune checkpoint inhibitors (ICIs), as a novel class of anticancer therapy, can be more efficacious and less toxic than chemotherapy, but their clinical success is confined to certain tumor types. Elucidating their targets, mechanisms and scope of action, and potential synergism with chemotherapy and/or targeted therapies are critical to widen their clinical indications. Treatment response to an ICI targeting programmed death-1 (anti-PD-1) is sought to be understood here by conducting a preplanned correlative analysis of a phase II clinical trial in patients with small bowel adenocarcinoma (SBA). The cytolytic capacity of circulating immune cells in cancer patients using a novel ex vivo cytotoxicity assay is evaluated, and the utility of circulating biomarkers is investigated to predict and monitor the treatment effect of anti-PD-1. Baseline expression of Bim and NKG7 and upregulation of CX3CR1 in circulating T cells are associated with the clinical benefit of anti-PD-1 in patients with SBA. Overall, these findings suggest that the frequency and cytolytic capacity of circulating, effector immune cells may differentiate clinical response to ICIs, providing a strong rationale to support immune monitoring using patient peripheral blood.

Silencing of A-kinase anchor protein 4 inhibits the metastasis and growth of non-small cell lung cancer

Non-small cell lung cancer (NSCLC) is one of the most malignant tumors. The treatment of advanced NSCLC can be challenging due to drug resistance. The discovery of novel cancer-testis antigens to develop new strategies for advanced metastatic NSCLC is required. AKAP4 is an oncogene discovered in some malignant tumors, and its molecular function of AKAP4 in NSCLC is unknown. This study aimed to explore the potential function of AKAP4 in the development and progression of NSCLC. AKAP-4 was found to be significantly upregulated in both clinical NSCLC tissues and NSCLC cell lines. Cell viability and migration were suppressed, apoptosis was induced, and tube formation was inhibited by the knockdown of AKAP-4, accompanied by the downregulation of VEGF, N-cadherin, EphA2, and MMP-2, and upregulation of c-AMP, PKA, and E-cadherin. In vivo xenograft experiments revealed that tumor growth was inhibited by the knockdown of AKAP4, accompanied by the activation of c-AMP/PKA signaling and inhibition of epithelial-mesenchymal transition progression. Our results show that AKAP4 might be an important target for treating NSCLC because of its function in promoting the migration and proliferation of NSCLC cells.

Phase II Evaluation of Stereotactic Ablative Radiotherapy (SABR) and Immunity in 11C-Choline-PET/CT-Identified Oligometastatic Castration-Resistant Prostate Cancer

PURPOSE

Outcomes for resistant metastatic castration-resistant prostate cancer (CRPC) are poor. Stereotactic ablative radiotherapy (SABR) induces antitumor immunity in clinical and preclinical studies, but immunologic biomarkers are lacking.

PATIENTS AND METHODS

Eighty-nine patients with oligometastatic CRPC were identified by ¹¹C-Choline-PET (Choline-PET) from August 2016 to December 2019 and treated with SABR. Prespecified coprimary endpoints were 2-year overall survival (OS) and PSA progression. Secondary endpoints included 2-year SABR-treated local failure and 6-month adverse events. Correlative studies included peripheral blood T-cell subpopulations before and after SABR.

RESULTS

128 lesions in 89 patients were included in this analysis. Median OS was 29.3 months, and 1- and 2-year OS were 96% and 80%, respectively. PSA PFS was 40% at 1 year and 21% at 2 years. Local PFS was 84.4% and 75.3% at 1 and 2 years, respectively, and no grade ≥3 AEs were observed. Baseline high levels of tumor-reactive T cells (T_TR; CD8⁺CD11a^high) predicted superior local, PSA, and distant PFS. Baseline high levels of effector memory T cells (T_EM; CCR7^-CD45RA^-) were associated with improved PSA PFS. An increase in T_TR at day 14 from baseline was associated with superior OS.

CONCLUSIONS

This is the first comprehensive effector T-cell immunophenotype analysis in a phase II trial before and after SABR in CRPC. Results are favorable and support the incorporation of immune-based markers in the design of future randomized trials in patients with oligometastatic CRPC treated with SABR.

Bim Expression in Peritumoral Lymphocytes is Associated with Survival in Patients with Metastatic Clear Cell Renal Cell Carcinoma

BACKGROUND: Bim (BCL-2-interacting mediator of cell death) is a downstream pro-apoptotic signaling molecule activated by the PD-1 pathway. OBJECTIVE: We sought to determine if Bim expression in peritumoral T-lymphocytes (PTLs) is associated with survival in patients with metastatic clear cell renal cell carcinoma (ccRCC). METHODS: Immunohistochemistry staining for Bim was performed on paraffin-embedded tumor tissue blocks from patients with metastatic ccRCC who underwent nephrectomy between 1990-2004. Associations of Bim expression with cancer-specific survival (CSS) and overall survival (OS) from date of metastasis were evaluated using multivariable Cox regression models, adjusting for age, sex, and metastases-score. RESULTS: 525 patients with metastatic ccRCC, of whom 169 (32%) had metastases at time of nephrectomy were studied. After multivariable adjustment, high Bim expression remained associated with worse CSS (HR = 1.31; 95% CI 1.07–1.59; p = 0.008) and OS (HR = 1.28; 95% CI 1.06–1.55; p = 0.01). The interaction between Bim and PD-L1 was not statistically significant for CSS (p = 0.68) or OS (p = 0.57), suggesting that the associations between Bim and survival outcomes were not significantly different based on tumor PD-L1 expression. CONCLUSION: High Bim expression in PTLs at nephrectomy is prognostic of worse CSS and OS in patients with metastatic ccRCC, irrespective of tumor PD-L1 expression. The role of earlier PD-1/PD-L1-directed therapy warrants evaluation in these patients.

Case Series of Pleomorphic Carcinoma of the Lung Treated With Immune Checkpoint Inhibitors

AIM

We report, herein, three cases of pleomorphic carcinoma of the lung treated with immune checkpoint inhibitors. Case 1: A 73-year-old man was diagnosed as having pleomorphic carcinoma of the lung and treated with pembrolizumab alone. However, he showed no response and died 4 months after the initiation of the treatment. Case 2: A 66-year-old man was diagnosed as having pleomorphic carcinoma of the lung. He was started on a combination regimen of pembrolizumab plus carboplatin plus nab-paclitaxel, and a remarkable response was observed. Case 3: A 49-year-old man was diagnosed as having pleomorphic carcinoma of the lung. He was started on pembrolizumab monotherapy as second-line treatment. Eleven months after the treatment initiation, computed tomography revealed the decrease of tumor diameter.

CONCLUSION

Immune checkpoint inhibitor therapy is expected to improve the prognosis of patients with pleomorphic carcinoma of the lung.

Anti-PD1 therapy induces lymphocyte-derived exosomal miRNA-4315 release inhibiting Bim-mediated apoptosis of tumor cells

Anti-PD1 immunotherapy, as a single agent or in combination with standard chemotherapies, has significantly improved the outcome of many patients with cancers. However, resistance to anti-PD1 antibodies often decreases the long-term therapeutic benefits. Despite this observation in clinical practice, the molecular mechanisms associated with resistance to anti-PD1 antibody therapy have not yet been elucidated. To identify the mechanisms of resistance associated with anti-PD1 antibody therapy, we developed cellular models including purified T cells and different cancer cell lines from glioblastoma, lung adenocarcinoma, breast cancer and ovarian carcinoma. A murine model of lung cancer was also used. Longitudinal blood samples of patients treated with anti-PD1 therapy were also used to perform a proof-of-concept study of our findings. We found that anti-PD1 exposure of T-cell promotes an enrichment of exosomal miRNA-4315. We also noted that exosomal miRNA-4315 induced a phenomenon of apopto-resistance to conventional chemotherapies in cancer cells receiving exosomal miRNA-4315. At molecular level, we discern that the apopto-resistance phenomenon was associated with the miRNA-4315-mediated downregulation of Bim, a proapoptotic protein. In cellular and mice models, we observed that the BH3 mimetic agent ABT263 circumvented this resistance. A longitudinal study using patient blood showed that miRNA-4315 and cytochrome c can be used to define the time period during which the addition of ABT263 therapy may effectively increase cancer cell death and bypass anti-PD1 resistance.This work provides a blood biomarker (exosomal miRNA-4315) for patient stratification developing a phenomenon of resistance to anti-PD1 antibody therapy and also identifies a therapeutic alternative (the use of a BH3 mimetic drug) to limit this resistance phenomenon.

Clinical significance of BIM deletion polymorphism in chemoradiotherapy for non-small cell lung cancer

The standard treatment for locally advanced non‐small cell lung cancer (NSCLC) is chemoradiotherapy (CRT) followed by anti‐programmed cell death‐ligand 1 (anti‐PD‐L1) treatment. BIM deletion polymorphism induces the suppression of apoptosis resulting from epidermal growth factor (EGFR)‐tyrosine kinase inhibitors in EGFR‐mutated NSCLC patients. We aimed to examine the effects of BIM polymorphism on CRT and anti‐PD‐L1/PD‐1 treatment in NSCLC patients. In this retrospective study of 1312 patients with unresectable NSCLC treated at Higashi‐Hiroshima Medical Center and Hiroshima University Hospital between April 1994 and October 2019, we enrolled those who underwent CRT or chemotherapy using carboplatin + paclitaxel or cisplatin + vinorelbine, or anti‐PD‐L1/PD‐1 treatment. Of 1312 patients, 88, 80, and 74 underwent CRT, chemotherapy, and anti‐PD‐L1/PD‐1 treatment, respectively, and 17.0%, 15.2% and 17.6% of these patients showed BIM polymorphism. Among patients receiving CRT, the progression‐free survival was significantly shorter in those with BIM deletion than in those without. In the multivariate analyses, BIM polymorphism was an independent factor of poor anti‐tumor effects. These results were not observed in the chemotherapy and anti‐PD‐L1/PD‐1 treatment groups. In in vitro experiments, BIM expression suppression using small interfering RNA in NSCLC cell lines showed a significantly suppressed anti‐tumor effect and apoptosis after irradiation but not chemotherapy. In conclusion, we showed that BIM polymorphism was a poor‐predictive factor for anti‐tumor effects in NSCLC patients who underwent CRT, specifically radiotherapy. In the implementation of CRT in patients with BIM polymorphism, we should consider subsequent treatment, keeping in mind that CRT may be insufficient.

Chemo-immunotherapy combination after PD-1 inhibitor failure improves clinical outcomes in metastatic melanoma patients

Management of PD-1 blockade resistance in metastatic melanoma (MM) remains challenging. Immunotherapy or chemotherapy alone provides limited benefit in this setting. Chemo-immunotherapy (CIT) has demonstrated favorable efficacy and safety profiles in lung cancer. Our pre-clinical study showed that in MM patients who have failed PD-1 blockade, the addition of chemotherapy increases CX3CR1+ therapy-responsive CD8+ T-cells with enhanced anti-tumor activity, resulting in improved clinical response. Here, we examined the clinical outcomes of CIT in MM patients after PD-1 blockade failure and the treatment-related changes in CX3CR1+ therapy-responsive CD8+ T-cells. We reviewed MM patients seen between January 2012 and June 2018 who failed anti-PD-1-based therapy and received subsequent CIT, immune checkpoint inhibitors (ICI) or chemotherapy alone. Overall survival (OS), objective response rate (ORR), event-free survival (EFS), and toxicities were assessed. Among 60 patients, 33 received CIT upon disease progression on PD-1 blockade. At a median follow-up of 3.9 years, the CIT group had a median OS of 3.5 years [95% confidence interval (CI) 1.7-NR] vs. 1.8 years (95% CI 0.9-2; P = 0.002) for those who received subsequent ICI (n = 9) or chemotherapy alone (n = 18), with ORR of 59% vs. 15% (P = 0.0003), respectively. The median EFS was 7.6 months (95% CI 6-10) following CIT vs. 3.4 months (95% CI 2.8-4.1; P = 0.0005) following ICI or chemotherapy alone. Therapy-responsive CX3CR1+CD8+ T-cells showed dynamic increase with successful CIT. CIT showed favorable clinical outcomes and acceptable safety profile in PD-1 blockade-resistant patients. CX3CR1+CD8+ therapy-responsive T-cells can be potentially used for monitoring disease response to CIT.

Biomarkers, measured during therapy, for response of melanoma patients to immune checkpoint inhibitors: a systematic review

Immune checkpoint inhibitors (ICIs), which target CTLA-4 or PD-(L)1 molecules, have shown impressive therapeutic results. Durable responses, however, are only observed in a segment of the patient population and must be offset against severe off-target immune toxicity and high costs. This calls for biomarkers that predict response during ICI treatment. Although many candidate biomarkers exist, as yet, there has been no systematic overview of biomarkers predictive during. Here, we provide a systematic review of the current literature of ICI treatment to establish an overview of candidate predictive biomarkers during ICI treatment in melanoma patients. We performed a systematic Medline search (2000-2018, 1 January) on biomarkers for survival or response to ICI treatment in melanoma patients. We retrieved 735 publications, of which 79 were finally included in this systematic review. Blood markers were largely studied for CTLA-4 ICI, whereas tumor tissue markers were analyzed for PD-(L)1 ICI. Blood cytology and soluble factors were more frequently correlated to overall survival (OS) than response, indicating their prognostic rather than predictive nature. An increase in tumor-infiltrating CD8 + T-cells and a decrease in regulatory T-cells were correlated to response, in addition to mutational load, neoantigen load, and immune-related gene expression. Immune-related adverse events were also associated frequently with a favorable response and OS. This review shows the great variety of potential biomarkers published to date, in an attempt to better understand response to ICI therapy; it also highlights the candidate markers for future research. The most promising biomarkers for response to ICI treatment are the occurrence of immune-related adverse events (especially vitiligo), lowering of lactate dehydrogenase, and increase in activated CD8 + and decrease in regulatory T-cells.

Clinical and Recent Patents Applications of PD-1/PD-L1 Targeting Immunotherapy in Cancer Treatment-Current Progress, Strategy, and Future Perspective

Targeting PD-L1 and PD-1 interactions is a relatively new therapeutic strategy used to treat cancer. Inhibitors of PD-1/PD-L1 include peptides, small molecule chemical compounds, and antibodies. Several approved antibodies targeting PD-1 or PD-L1 have been patented with good curative effect in various cancer types in clinical practices. While the current antibody therapy is facing development bottleneck, some companies have tried to develop PD-L1 companion tests to select patients with better diagnosis potential. Meanwhile, many companies have recently synthesized small molecule inhibitors of PD-1/PD-L1 interactions and focused on searching for novel biomarker to predict the efficacy of anti-PD-1/PD-L1 drugs. This review summarized clinical studies and patent applications related to PD-1/PD-L1 targeted therapy and also discussed progress in inhibitors of PD-1/PD-L1.

ADAM10 and ADAM17 cleave PD-L1 to mediate PD-(L)1 inhibitor resistance

ADAM10 and ADAM17 expression and soluble PD-L1 (sPD-L1) predict poor prognosis in many malignancies, including in patients treated with PD-(L)1 inhibitors. The mechanism of soluble PD-L1 production and its effects are unknown. Here we uncover a novel mechanism of ADAM10- and ADAM17-mediated resistance to PD-(L)1 inhibitors. ADAM10 and ADAM17 cleave PD-L1 from the surface of malignant cells and extracellular vesicles. This cleavage produces an active sPD-L1 fragment that induces apoptosis in CD8 + T cells and compromises the killing of tumor cells by CD8 + T cells. Reduced tumor site PD-L1 protein-to-mRNA ratios predict poor outcomes and are correlated with elevated ADAM10 and ADAM17 expression in multiple cancers. These results may explain the discordance between PD-L1 immunohistochemistry and PD-(L)1 inhibitor response. Thus, including ADAM10 and ADAM17 tissue staining may improve therapy selection. Furthermore, treatment with an ADAM10/ADAM17 inhibitor may abrogate PD-(L)1 inhibitor resistance and improve clinical responses to PD-(L)1 immunotherapy.

Hypereosinophilia in a patient with metastatic non-small-cell lung cancer treated with antiprogrammed cell death 1 (anti-PD-1) therapy

Immune checkpoint inhibitors have changed the treatment paradigm for patients with cancer. Though a majority of patients tolerate treatment, some develop hematologic toxicities, including eosinophilia. Eosinophilia has been associated with better responses in some patients with melanoma, but this has not been investigated in non-small-cell lung cancer. We present a case of a woman with metastatic lung adenocarcinoma who developed asymptomatic hypereosinophilia after initiation of nivolumab. Her eosinophil count temporarily decreased after transiently stopping the medication, but increased again after re-initiation. She had a favorable tumor response to therapy. This exemplifies the potential role of eosinophilia as a peripheral, readily available biomarker of favorable response to immunotherapy in patients with lung cancer. Awareness of this manifestation is important.

Association Between Response to Nivolumab Treatment and Peripheral Blood Lymphocyte Subsets in Patients With Non-small Cell Lung Cancer

Immune checkpoint blockade represents a major breakthrough in advanced non-small cell lung cancer (NSCLC) therapy. However, success is limited to a subset of patients and there is a critical need to identify robust biomarkers associated with clinical response. In this study, we assessed whether pre-existing immunological characteristics, as well as immune parameters measured during treatment, might provide such clinical guidance. We studied blood samples collected at baseline and during treatment in a cohort of advanced NSCLC patients (n = 74) treated with nivolumab. Several lymphocyte subsets and biomarkers were then correlated with overall survival (OS) as well as clinical response, assessed using RECIST criteria. We found that patients characterized by longer OS had higher levels of CD3⁺, CD4⁺, and CD8⁺ T cells but lower levels of NK cells at baseline. Moreover, that they displayed a statistically significant lower expression of PD-1 on both CD3⁺ and CD8⁺ T cells (p = 0.013 and p = 0.033, respectively). The pre-treatment level of exhausted T cells (CD8⁺PD1⁺Eomes⁺) was significantly lower in patients with controlled disease (CD), defined as partial response (PR), and stable disease (SD), compared to those with progressive disease (PD) (p = 0.046). In CD patients, the frequency of exhausted CD8⁺ T cells further decreased during treatment cycles (p = <0.0001, p = 0.0032, and p = 0.0239, respectively). In conclusion, our results suggest that the distribution of lymphocyte subsets and expression of PD-1 on T cells before treatment may help predict the outcome of anti-PD-1 treatment in NSCLC patients. In addition, assessing the initial levels of exhausted T cells as well as their decrease upon treatment may also predict response and clinical outcome.

Genetic and Epigenetic Biomarkers of Immune Checkpoint Blockade Response

Checkpoint inhibitor therapy constitutes a promising cancer treatment strategy that targets the immune checkpoints to re-activate silenced T cell cytotoxicity. In recent pivotal trials, immune checkpoint blockade (ICB) demonstrated durable responses and acceptable toxicity, resulting in the regulatory approval of 8 checkpoint inhibitors to date for 15 cancer indications. However, up to ~85% of patients present with innate or acquired resistance to ICB, limiting its clinical utility. Current response biomarker candidates, including DNA mutation and neoantigen load, immune profiles, as well as programmed death-ligand 1 (PD-L1) expression, are only weak predictors of ICB response. Thus, identification of novel, more predictive biomarkers that could identify patients who would benefit from ICB constitutes one of the most important areas of immunotherapy research. Aberrant DNA methylation (5mC) and hydroxymethylation (5hmC) were discovered in multiple cancers, and dynamic changes of the epigenomic landscape have been identified during T cell differentiation and activation. While their role in cancer immunosuppression remains to be elucidated, recent evidence suggests that 5mC and 5hmC may serve as prognostic and predictive biomarkers of ICB-sensitive cancers. In this review, we describe the role of epigenetic phenomena in tumor immunoediting and other immune evasion related processes, provide a comprehensive update of the current status of ICB-response biomarkers, and highlight promising epigenomic biomarker candidates.

Predicting response to pembrolizumab in metastatic melanoma by a new personalization algorithm

BACKGROUND

At present, immune checkpoint inhibitors, such as pembrolizumab, are widely used in the therapy of advanced non-resectable melanoma, as they induce more durable responses than other available treatments. However, the overall response rate does not exceed 50% and, considering the high costs and low life expectancy of nonresponding patients, there is a need to select potential responders before therapy. Our aim was to develop a new personalization algorithm which could be beneficial in the clinical setting for predicting time to disease progression under pembrolizumab treatment.

METHODS

We developed a simple mathematical model for the interactions of an advanced melanoma tumor with both the immune system and the immunotherapy drug, pembrolizumab. We implemented the model in an algorithm which, in conjunction with clinical pretreatment data, enables prediction of the personal patient response to the drug. To develop the algorithm, we retrospectively collected clinical data of 54 patients with advanced melanoma, who had been treated by pembrolizumab, and correlated personal pretreatment measurements to the mathematical model parameters. Using the algorithm together with the longitudinal tumor burden of each patient, we identified the personal mathematical models, and simulated them to predict the patient's time to progression. We validated the prediction capacity of the algorithm by the Leave-One-Out cross-validation methodology.

RESULTS

Among the analyzed clinical parameters, the baseline tumor load, the Breslow tumor thickness, and the status of nodular melanoma were significantly correlated with the activation rate of CD8+ T cells and the net tumor growth rate. Using the measurements of these correlates to personalize the mathematical model, we predicted the time to progression of individual patients (Cohen's κ = 0.489). Comparison of the predicted and the clinical time to progression in patients progressing during the follow-up period showed moderate accuracy (R2 = 0.505).

CONCLUSIONS

Our results show for the first time that a relatively simple mathematical mechanistic model, implemented in a personalization algorithm, can be personalized by clinical data, evaluated before immunotherapy onset. The algorithm, currently yielding moderately accurate predictions of individual patients' response to pembrolizumab, can be improved by training on a larger number of patients. Algorithm validation by an independent clinical dataset will enable its use as a tool for treatment personalization.

The Transcription Factor Bhlhe40 Programs Mitochondrial Regulation of Resident CD8+ T Cell Fitness and Functionality

Tissue-resident memory CD8⁺ T (Trm) cells share core residency gene programs with tumor-infiltrating lymphocytes (TILs). However, the transcriptional, metabolic, and epigenetic regulation of Trm cell and TIL development and function is largely undefined. Here, we found that the transcription factor Bhlhe40 was specifically required for Trm cell and TIL development and polyfunctionality. Local PD-1 signaling inhibited TIL Bhlhe40 expression, and Bhlhe40 was critical for TIL reinvigoration following anti-PD-L1 blockade. Mechanistically, Bhlhe40 sustained Trm cell and TIL mitochondrial fitness and a functional epigenetic state. Building on these findings, we identified an epigenetic and metabolic regimen that promoted Trm cell and TIL gene signatures associated with tissue residency and polyfunctionality. This regimen empowered the anti-tumor activity of CD8⁺ T cells and possessed therapeutic potential even at an advanced tumor stage in mouse models. Our results provide mechanistic insights into the local regulation of Trm cell and TIL function.

Immunotherapy in Non-Small Cell Lung Cancer: Facts and Hopes

Immune-checkpoint inhibitors (ICI), particularly inhibitors of the PD-1 axis, have altered the management of non-small cell lung cancer (NSCLC) over the last 10 years. First demonstrated to improve outcomes in second-line or later therapy of advanced disease, ICIs were shown to improve overall survival compared with chemotherapy in first-line therapy for patients whose tumors express PD-L1 on at least 50% of cells. More recently, combining ICIs with chemotherapy has been shown to improve survival in patients with both squamous and nonsquamous NSCLC, regardless of PD-L1 expression. However, PD-L1 and, more recently, tumor mutational burden have not proven to be straightforward indicative biomarkers. We describe the advances to date in utilizing these biomarkers, as well as novel markers of tumor inflammation, to ascertain which patients are most likely to benefit from ICIs. Ongoing translational work promises to improve the proportion of patients who benefit from these agents.

Biomarkers of hyperprogression and pseudoprogression with immune checkpoint inhibitor therapy

Hyperprogression and pseudoprogression are two atypical responses to immune checkpoint inhibitor therapy that affect therapeutic decisions and prognosis. Identification of predictive biomarkers for atypical responses either before or during treatment remains a huge unmet need in cancer immunotherapy. Many studies have looked at potential biomarkers, including clinical factors and laboratory findings (e.g., peripheral blood counts, circulating tumor DNA, cytokine levels). The results of these studies have been inconsistent, possibly due to small sample sizes, different tumor types and heterogeneity of the definition of these atypical responses.

Paradox-driven adventures in the development of cancer immunology and immunotherapy

After more than one hundred years of documented trials, immunotherapy has become a standard of care in the treatment of human cancer. Much of the knowledge that led to recent breakthroughs seems quite logical from today's point of view. However, what we now cite as facts were originally considered paradoxes, meaning something contrary to expectations or perceived opinion at the time. In order to make gains in the field of immunotherapy, one had to be willing to confront ideas and concepts that seemed to contradict one another, and reconcile how each could be true. This is what led to new knowledge and advances. Here, we highlight some of these paradoxes and the milestone discoveries that followed, each one critical for our understanding of immune checkpoint pathways. By outlining some of the steps that we took and the challenges that we overcame, we hope to inspire and encourage future generations of researchers to confront the paradoxes that still permeate the field.

In vitro assay for the development of small molecule inhibitors targeting PD-1/PD-L1

Cancer immunotherapy has recently emerged as one of the hot research field since clinical successes achieved by antibody drugs of immune checkpoints, among which PD-1 and its ligand PD-L1 are the well established molecules. PD-1/PD-L1 pathway induces immune tolerance and immune evasion, especially in tumor microenvironment, cancer cell is capable to escape the immune surveillance by up-regulating the expression level of PD-1 or PD-L1. Blockade of PD-1/PD-L1 can unleash the anti-tumor activity, and the strategy shows great successes in the treatment of various cancer types in the late stage. Beside antibody drugs, many other molecules such as peptides, high affinity PD(L)-1 mutants, chemical compounds, and DNA aptamers are designed for inhibitors of PD-1/PD-L1 pathway. Each modulators show their pros and cons based on their own physiochemical properties. Here we introduced the methods for identifying low molecular weight inhibitors of PD-1/PD-L1 and mainly discussed the cell-based blocking test.

Correlation between serum adenosine deaminase activity and efficacy of anti-programmed cell death-1 antibody

OBJECTIVE

Serum adenosine deaminase (ADA) activity is a marker of immune reaction to several diseases. We evaluated changes in serum ADA in patients with lung cancer undergoing chemotherapy or anti-programmed cell death-1 (PD-1) therapy to examine the correlation between serum ADA and the therapy efficacy.

MATERIALS AND METHODS

We assessed 50 patients with advanced lung cancer receiving chemotherapy or anti-PD-1 therapy. Serum ADA was measured before and on day 7 of the first treatment cycle and day 0 of subsequent cycles. Correlations between ADA change and efficacy of treatment were evaluated.

RESULTS

Of the 50 patients, 20 were treated with chemotherapy and 30 were treated with anti-PD-1 therapy. Serum ADA decreased significantly between baseline and day 7 of the first cycle in patients undergoing chemotherapy, regardless of response (partial response [PR] or stable disease [SD]: -23% [-38 to +32; p =  0.002]; progressive disease [PD]: -12% [-42 to +6; p =  0.500]). Conversely, in patients undergoing anti-PD-1 therapy, serum ADA increased significantly between baseline and 7 days after the first dose and before subsequent doses in patients who had PR or SD. (day 7 of first cycle: +6% [-10 to +34; p =  0.034], day 0 of second cycle: 8% [-5 to +37; p =  0.002], day 0 of third cycle: 9% [-3 to +55; p =  0.002]). However, serum ADA did not significant change in PD patients undergoing anti-PD-1 therapy. Furthermore, early increases in serum ADA were associated with longer progression-free survival in patients receiving anti-PD-1 therapy (p =  0.006).

CONCLUSION

Changes in serum ADA could be used to predict clinical benefit from anti-PD-1 therapy in patients with lung cancer. The association between changes in serum ADA and the efficacy of ant-PD-1 therapy thus remains inconclusive and requires further study.

Predictive biomarkers for PD-1 and PD-L1 immune checkpoint blockade therapy

The immune system is very important for monitoring and eradicating cancer cells. However, there may be multiple immunosuppressive mechanisms to prevent effective antitumor immunity in the tumor environment, such as the negative immunologic regulators known as checkpoints. Antibodies that block the checkpoints programmed cell death protein 1 (PD-1) pathway have made great success. Nevertheless, the response rates are likely to vary widely. Therefore, several researches are currently underway to determine which biomarkers are able to identify the group of patients who can obtain benefits from PD-1 and programmed cell death-ligand 1 (PD-L1) immune checkpoint blockade therapy. This review focuses on potential predictive biomarkers for PD-1/PD-L1 checkpoint blockade immunotherapy in order to provide advice and guidance for clinical treatment.

The PD-1/PD-L1 Pathway Affects the Expansion and Function of Cytotoxic CD8+ T Cells During an Acute Retroviral Infection

Cytotoxic CD8⁺ T lymphocytes (CTL) efficiently control acute virus infections but can become exhausted when a chronic infection develops. The checkpoint receptor PD-1 suppresses the functionality of virus-specific CD8⁺ T cells during chronic infection. However, the role of the PD-L1/PD-1 pathway during the acute phase of infections has not been well characterized. In the current study the effects of PD-1 or PD-L1 deficiency on the CD8⁺ T cell response against Friend retroviral (FV) infection of knockout mice was analyzed during acute infection. We observed an enhanced proliferation, functional maturation, and reduced apoptosis of effector CD8⁺ T cells in the absence of PD-1 or PD-L1. The knockout of PD-L1 had a stronger effect on the functionality of CD8⁺ T cells than that of PD-1. Augmented CTL responses were associated with an improved control of FV replication. The strong phenotype of FV-infected PD-L1 knockout mice was independent of the interaction with CD80 as an additional receptor for PD-L1. Furthermore, we performed a detailed analysis of the production of different granzymes in virus-specific CD8⁺ T cells and observed that especially the simultaneous production of multiple granzymes in individual T cells (multifunctionality) was under the control of the PD-1/PD-L1 pathway. The findings from this study allow for a better understanding of the development of antiviral cytotoxic immunity during acute viral infections.

Prostate cancer and inflammation: A new molecular imaging challenge in the era of personalized medicine

The relationship between cancer and inflammation is one of the most important fields for both clinical and translational research. Despite numerous studies reported interesting and solid data about the prognostic value of the presence of inflammatory infiltrate in cancers, the biological role of inflammation in prostate cancer development is not yet fully clarified. The characterization of molecular pathways that connect altered inflammatory response and prostate cancer progression can provide the scientific rationale for the identification of new prognostic and predictive biomarkers. Specifically, the detection of infiltrating immune cells or related-cytokines by histology and/or by molecular imaging techniques could profoundly change the management of prostate cancer patients. In this context, the anatomic pathology and imaging diagnostic teamwork can provide a valuable support for the validation of new targets for diagnosis and therapy of prostate cancer lesions associated to the inflammatory infiltrate. The aim of this review is to summarize the current literature about the role of molecular imaging technique and anatomic pathology in the study of the mutual interaction occurring between prostate cancer and inflammation. Specifically, we reported the more recent advances in molecular imaging and histological methods for the early detection of prostate lesions associated to the inflammatory infiltrate.

MLL3 enhances the transcription of PD-L1 and regulates anti-tumor immunity

Tumor cells utilize the overexpression of the programmed death-1 ligand 1(PD-L1) to escape T-cell controlled immune-surveillance. The clinical therapy that dilapidates PD1 or PD-L1-mediated cancer tolerance has pushed out the need to uncover the molecular regulation of PD-L1 overexpression in the tumor cell. In this study, we identify histone methyltransferase mixed-lineage leukemia protein 3 (MLL3) as a critical regulator of PD-L1 in prostate cancer cells. MLL3 and PD-L1 were highly expressed in the metastatic cancer tissues, compared to the primary cancer tissues. Furthermore, their expressions were highly correlated in the cancer tissues in the databases of TCGA and Xiangya Hospital. We found that MLL3 bound to the enhancer of PD-L1. Depletion of MLL3 decreased the binding level of H3K4me1 in the enhancer of PD-L1 and Pol II Ser-5p in the promoter of PD-L1. Importantly, MLL3 depletion impaired the mouse xenograft growth and decreased the response to PD-L1 antibody treatment in mice. The findings extend the understanding of the biology regulation of PD-L1 transcription and identify the histone writer MLL3 in an important immune checkpoint, and give prominence to a hidden therapeutic target to conquer immune evasion by tumor cells.

Prospective Immunophenotyping of CD8+ T Cells and Associated Clinical Outcomes of Patients With Oligometastatic Prostate Cancer Treated With Metastasis-Directed SBRT

PURPOSE

This study examined the effects of metastasis-directed stereotactic body radiation therapy (mdSBRT) on CD8⁺ T-cell subpopulations and correlated post-mdSBRT immunophenotypic responses with clinical outcomes in patients with oligometastatic prostate cancer (OPCa).

METHODS AND MATERIALS

Peripheral blood mononuclear cells were prospectively isolated from 37 patients with OPCa (≤3 metastases) who were treated with mdSBRT. Immunophenotyping identified circulating CD8⁺ T-cell subpopulations, including tumor-reactive (T_TR), effector memory, central memory (T_CM), effector, and naïve T cells from samples collected before and after mdSBRT. Univariate Cox proportional hazards regression was used to assess whether changes in these T-cell subpopulations were potential risk factors for death and/or progression. The Kaplan-Meier method was used for survival. Cumulative incidence for progression and new distant metastasis weas estimated, considering death as a competing risk.

RESULTS

Median follow-up was 39 months (interquartile range, 34-43). Overall survival at 3 years was 78.2%. Cumulative incidence for local progression and new distant metastasis at 3 years was 16.5% and 67.6%, respectively. Between baseline and day 14 after mdSBRT, an increase in the T_CM cell subpopulation was associated with the risk of death (hazard ratio, 1.22 [95% confidence interval, 1.02-1.47]; P = .033), and an increase in the T_TR cell subpopulation was protective against the risk of local progression (hazard ratio, 0.80 [95% confidence interval, 0.65-0.98]; P = .032).

CONCLUSIONS

An increase in the T_TR cell subpopulation was protective against the risk of disease progression, and an increase in the T_CM cell subpopulation was associated with the risk of death in patients with OPCa treated with mdSBRT. Disease control may be further improved by better understanding the CD8⁺ T-cell subpopulations and by enhancing their antitumor effect.

Inhibitors of the PD-1 Pathway in Tumor Therapy

The programmed death 1 (PD-1) pathway delivers inhibitory signals that function as a brake for immune responses. This pathway limits the initiation and duration of immune responses, thereby protecting tissues from immune-mediated damage and autoimmune diseases. However, the PD-1 pathway also inhibits immune responses to tumors. The critical role of PD-1 in preventing antitumor immunity is demonstrated by the transformative effects of PD-1 pathway blockade in a broad range of cancers with the hallmark of durability of response. Despite this success, most patients do not respond to PD-1 monotherapy, and some patients experience adverse events. In this review, we discuss the functions of the PD-1 pathway and its translation to cancer immunotherapy. We also consider current challenges and opportunities for PD-1 cancer immunotherapy, including mechanisms of response and resistance, identification of biomarkers of response to PD-1 therapy, characterization and treatment of PD-1 therapy-related adverse events, and development of safe and effective combination therapies.

Can IDO activity predict primary resistance to anti-PD-1 treatment in NSCLC?

Background

Immune checkpoint inhibitors have revolutionized the treatment paradigm of highly lethal malignancies like advanced non-small cell lung cancer (NSCLC), demonstrating long-term tumour control and extended patient survival. Unfortunately, only 25–30% of patients experience a durable benefit, while the vast majority demonstrate primary or acquired resistance. Recently, indoleamine 2,3-dioxygenase (IDO) activity has been proposed as a possible mechanism of resistance to anti-PD-1 treatment leading to an immunosuppressive microenvironment.

Methods

Pre-treatment serum concentrations of tryptophan (trp) and kynurenine (kyn) were measured by high-performance liquid chromatography tandem mass spectrometry in NSCLC patients treated with second-line nivolumab. The IDO activity was expressed with kyn/trp ratio. The associations between kyn/trp ratio and early progression, performance status (PS), age, sex, brain metastases, pleural effusion, progression free survival (PFS) and overall survival (OS) were analyzed using Spearman test and Mann–Whitney test.

Results

Twenty-six NSCLC patients were included in our study; 14 of them (54%) presented early progression (< 3 months) to nivolumab treatment. The median value of kyn/trp ratio was 0.06 µg/ml and the median value of quinolinic acid was 68.45 ng/ml. A significant correlation between early progression and higher kyn/trp ratio and quinolinic acid concentration was observed (p = 0.017 and p = 0.005, respectively). Patients presenting lower values of kyn/trp ratio and quinolinic acid levels showed longer PFS (median PFS not reached versus 3 months; HR: 0.3; p = 0.018) and OS (median OS not reached vs 3 months; HR: 0.18; p = 0.0005).

Conclusion

IDO activity, expressed as kyn/trp ratio, is associated with response to immunotherapy; in particular, higher kyn/trp ratio could predict resistance to anti-PD-1 treatment. These preliminary results suggest the possibility of using anti-PD-1 plus IDO inhibitor in those patients with high level of kyn/trp ratio.

Circulating T Cell Subpopulations Correlate With Immune Responses at the Tumor Site and Clinical Response to PD1 Inhibition in Non-Small Cell Lung Cancer

Agents targeting the PD1-PDL1 axis have transformed cancer therapy. Factors that influence clinical response to PD1-PDL1 inhibitors include tumor mutational burden, immune infiltration of the tumor, and local PDL1 expression. To identify peripheral correlates of the anti-tumor immune response in the absence of checkpoint blockade, we performed a retrospective study of circulating T cell subpopulations and matched tumor gene expression in melanoma and non-small cell lung cancer (NSCLC) patients. Notably, both melanoma and NSCLC patients whose tumors exhibited increased inflammatory gene transcripts presented high CD4⁺ and CD8⁺ central memory T cell (CM) to effector T cell (Eff) ratios in blood. Consequently, we evaluated CM/Eff T cell ratios in a second cohort of NSCLC. The data showed that high CM/Eff T cell ratios correlated with increased tumor PDL1 expression. Furthermore, of the 22 patients within this NSCLC cohort who received nivolumab, those with high CM/Eff T cell ratios, had longer progression-free survival (PFS) (median survival: 91 vs. 215 days). These findings show that by providing a window into the state of the immune system, peripheral T cell subpopulations inform about the state of the anti-tumor immune response and identify potential blood biomarkers of clinical response to checkpoint inhibitors in melanoma and NSCLC.

Changes in serum interleukin-8 (IL-8) levels reflect and predict response to anti-PD-1 treatment in melanoma and non-small-cell lung cancer patients

Background

Surrogate biomarkers of efficacy are needed for anti-PD1/PD-L1 therapy, given the existence of delayed responses and pseudo-progressions. We evaluated changes in serum IL-8 levels as a biomarker of response to anti-PD-1 blockade in melanoma and non-small-cell lung cancer (NSCLC) patients.

Patients and methods

Metastatic melanoma and NSCLC patients treated with nivolumab or pembrolizumab alone or nivolumab plus ipilimumab were studied. Serum was collected at baseline; at 2-4 weeks after the first dose; and at the time-points of response evaluation. Serum IL-8 levels were determined by sandwich ELISA. Changes in serum IL-8 levels were compared with the Wilcoxon test and their strength of association with response was assessed with the Mann-Whitney test. Accuracy of changes in IL-8 levels to predict response was estimated using receiver operation characteristics curves.

Results

Twenty-nine melanoma patients treated with nivolumab or pembrolizumab were studied. In responding patients, serum IL-8 levels significantly decreased between baseline and best response (P <0.001), and significantly increased upon progression (P =  0.004). In non-responders, IL-8 levels significantly increased between baseline and progression (P =  0.013). Early changes in serum IL-8 levels (2-4 weeks after treatment initiation) were strongly associated with response (P <0.001). These observations were validated in 19 NSCLC patients treated with nivolumab or pembrolizumab (P =  0.001), and in 15 melanoma patients treated with nivolumab plus ipilimumab (P <0.001). Early decreases in serum IL-8 levels were associated with longer overall survival in melanoma (P =  0.001) and NSCLC (P =  0.015) patients. Serum IL-8 levels also correctly reflected true response in three cancer patients presenting pseudoprogression.

Conclusions

Changes in serum IL-8 levels could be used to monitor and predict clinical benefit from immune checkpoint blockade in melanoma and NSCLC patients.

CX3CR1 identifies PD-1 therapy-responsive CD8+ T cells that withstand chemotherapy during cancer chemoimmunotherapy

Although immune checkpoint inhibitors have resulted in durable clinical benefits in a subset of patients with advanced cancer, some patients who did not respond to initial anti-PD-1 therapy have been found to benefit from the addition of salvage chemotherapy. However, the mechanism responsible for the successful chemoimmunotherapy is not completely understood. Here we show that a subset of circulating CD8+ T cells expressing the chemokine receptor CX3CR1 are able to withstand the toxicity of chemotherapy and are increased in patients with metastatic melanoma who responded to chemoimmunotherapy (paclitaxel and carboplatin plus PD-1 blockade). These CX3CR1+CD8+ T cells have effector memory phenotypes and the ability to efflux chemotherapy drugs via the ABCB1 transporter. In line with clinical observation, our preclinical models identified an optimal sequencing of chemoimmunotherapy that resulted in an increase of CX3CR1+CD8+ T cells. Taken together, we found a subset of PD-1 therapy-responsive CD8+ T cells that were capable of withstanding chemotherapy and executing tumor rejection with their unique abilities of drug efflux (ABCB1), cytolytic activity (granzyme B and perforin), and migration to and retention (CX3CR1 and CD11a) at tumor sites. Future strategies to monitor and increase the frequency of CX3CR1+CD8+ T cells may help to design effective chemoimmunotherapy to overcome cancer resistance to immune checkpoint blockade therapy.

Combining a GSI and BCL-2 inhibitor to overcome melanoma's resistance to current treatments

Major limitations of current melanoma treatments are for instances of relapse and the lack of therapeutic options for BRAF wild-type patients who do not respond to immunotherapy. Many studies therefore focus on killing resistant subpopulations, such as Melanoma Initiating Cells (MICs) to prevent relapse. Here we examined whether combining a GSI (γ-Secretase Inhibitor) with ABT-737 (a small molecule BCL-2/BCL-XL/BCL-W inhibitor) can kill both the non-MICs (bulk of melanoma) and MICs. To address the limitations of melanoma therapies, we included multiple tumor samples of patients relapsed from current treatments, with a diverse genetic background (with or without the common BRAF, NRAS or NF1 mutations) in these studies. Excitingly, the combination treatment reduced cell viability and induced apoptosis of the non-MICs; disrupted primary spheres, decreased the ALDH+ cells, and inhibited the self-renewability of the MICs in multiple melanoma cell lines and relapsed patient samples. Using a low-cell-number mouse xenograft model, we demonstrated that the combination significantly reduced the tumor initiating ability of MIC-enriched cultures from relapsed patient samples. Mechanistic studies also indicate that cell death is NOXA-dependent. In summary, this combination may be a promising strategy to address treatment relapse and for triple wild-type patients who do not respond to immunotherapy.

Modeling tumor immunity of mouse glioblastoma by exhausted CD8+ T cells

T cell exhaustion occurs during chronic infection and cancers. Programmed cell death protein-1 (PD-1) is a major inhibitory checkpoint receptor involved in T cell exhaustion. Blocking antibodies (Abs) against PD-1 or its ligand, PD-L1, have been shown to reverse T cell exhaustion during chronic infection and cancers, leading to improved control of persistent antigen. However, modeling tumor-specific T cell responses in mouse has been difficult due to the lack of reagents to detect and phenotype tumor-specific immune responses. We developed a novel mouse glioma model expressing a viral epitope derived from lymphocytic choriomeningitis virus (LCMV), which allowed monitoring of tumor-specific CD8 T-cell responses. These CD8 T cells express high levels of PD-1 and are unable to reject tumors, but this can be reversed by anti-PD-1 treatment. These results suggest the efficacy of PD-1 blockade as a treatment for glioblastoma, an aggressive tumor that results in a uniformly lethal outcome. Importantly, this new syngeneic tumor model may also provide further opportunities to characterize anti-tumor T cell exhaustion and develop novel cancer immunotherapies.

Perspective on immune oncology with liquid biopsy, peripheral blood mononuclear cells, and microbiome with non-invasive biomarkers in cancer patients

Antibodies against immune checkpoint inhibitors such as anti-programmed cell death protein 1 (PD-1) and anti-programmed death ligand 1 (PD-L1) play a key role in the treatment of advanced lung cancer. To examine the clinical benefits of these agents, preclinical and clinical studies have been conducted to identify definitive biomarkers associated with cancer status. Analysis of the blood and feces of tumor patients has attracted attention in recent studies attempting to identify non-invasive biomarkers such as cytokines, soluble PD-L1, peripheral blood mononuclear cells, and gut microbiota. These factors are believed to interact with each other to produce synergistic effects and contribute to the formation of the tumor immune microenvironment through the seven steps of the cancer immunity cycle. The immunogram was first introduced as a novel indicator to define the immunity status of cancer patients. In this review, we discuss the progress in the identification of predictive biomarkers as well as future prospects for anti-PD-1/PD-L1 therapy.

Posttranscriptional Control of PD-L1 Expression by 17β-Estradiol via PI3K/Akt Signaling Pathway in ERα-Positive Cancer Cell Lines

OBJECTIVE

Estrogen is a well-known oncogenic driver in endometrial (ECs) and breast cancers (BCs). Programmed cell death protein 1 (PD-1) and its ligands PD-1 Ligand 1 (PD-L1) and PD-L2 have been shown to mediate immune evasion of the tumor cells. The purpose of the present study was to assess the effects of estrogen on PD-L1 and PD-L2 expression in EC and BC cell lines.

METHODS

17β-Estradiol (E2)-induced expression of PD-L1 and PD-L2 and possible signaling pathway were investigated in EC and BC cells. Coculture of T cells and cancer cells with E2 stimulation was performed to assess the functions of T cells.

RESULTS

We found that E2 increased expression of PD-L1, but not PD-L2, protein via activation of phosphoinositide 3-kinase (PI3K)/Akt pathway in Ishikawa and Michigan Cancer Foundation-7 (MCF-7) cells. Phosphoinositide 3-kinase and Akt inhibitors could block E2's effects. 17β-Estradiol did not increase PD-L1 mRNA transcription, but stabilized PD-L1 mRNA. 17β-Estradiol's effects were only observed in estrogen receptor α (ERα)-positive Ishikawa and MCF-7 cells, but not in ERα-negative MDA-MB-231 cells. Coculture of Ishikawa or MCF-7 cells with T cells inhibited expression of interferon-γ and interleukin-2 and increased BCL-2-interacting mediator of cell death expression in the presence of E2.

CONCLUSIONS

This study provides the first evidence that estrogen upregulates PD-L1 protein expression in ERα-positive EC and BC cells to suppress immune functions of T cells in the tumor microenvironment, demonstrating a new mechanism of how estrogen drives cancer progression.

PD-1/PD-L1 Blockade: Have We Found the Key to Unleash the Antitumor Immune Response?

PD-1–PD-L1 interaction is known to drive T cell dysfunction, which can be blocked by anti-PD-1/PD-L1 antibodies. However, studies have also shown that the function of the PD-1–PD-L1 axis is affected by the complex immunologic regulation network, and some CD8⁺ T cells can enter an irreversible dysfunctional state that cannot be rescued by PD-1/PD-L1 blockade. In most advanced cancers, except Hodgkin lymphoma (which has high PD-L1/L2 expression) and melanoma (which has high tumor mutational burden), the objective response rate with anti-PD-1/PD-L1 monotherapy is only ~20%, and immune-related toxicities and hyperprogression can occur in a small subset of patients during PD-1/PD-L1 blockade therapy. The lack of efficacy in up to 80% of patients was not necessarily associated with negative PD-1 and PD-L1 expression, suggesting that the roles of PD-1/PD-L1 in immune suppression and the mechanisms of action of antibodies remain to be better defined. In addition, important immune regulatory mechanisms within or outside of the PD-1/PD-L1 network need to be discovered and targeted to increase the response rate and to reduce the toxicities of immune checkpoint blockade therapies. This paper reviews the major functional and clinical studies of PD-1/PD-L1, including those with discrepancies in the pathologic and biomarker role of PD-1 and PD-L1 and the effectiveness of PD-1/PD-L1 blockade. The goal is to improve understanding of the efficacy of PD-1/PD-L1 blockade immunotherapy, as well as enhance the development of therapeutic strategies to overcome the resistance mechanisms and unleash the antitumor immune response to combat cancer.