PD-L1 Levels Research Articles

Effect of ionizing radiation on JAK/STAT pathway and immune microenvironment in cervical cancer.

e17516 Background: STAT proteins play an important role in the development and progression of cervical cancer, and inhibition of the JAK/STAT pathway may be critical for enhancing tumor cell death. Delivering a certain dose of ionizing radiation (IR) directly to the lesion is one of the conventional treatments for cervical cancer. Whether IR will trigger changes in the JAK/STAT pathway and tumor immune microenvironment (TIME) is unknown and continues to be explored. Methods: We collected 30 patients received IR therapy with locally advanced cervical cancer (LACC) at the Affiliated Hospital of Qingdao University. Matched pre-IR and post-IR tumor tissue samples were collected from all patients, and the samples underwent RNA sequencing based on the nCounter platform (NanoString Technologies, Seattle, USA) and protein testing based on immunohistochemistry (IHC) staining. All tumor TIME cell infiltration scores were calculated as arithmetic mean of the constituent genes. P-values were calculated via the T Test. Results: RNA sequencing of tumor tissue from LACC patients before and after IR showed 35 differential genes. The results of GSEA pathway enrichment analysis of differential genes showed that compared with before IR, the IFN-α response pathway, IFN-γ response pathway and epithelial mesenchymal transition pathway were significantly up-regulated and enriched after IR. These three pathways collectively affect changes in the downstream JAK/STAT pathway. Moreover, compared with before IR, the cell infiltration abundance of overall macrophages (P=0.0087) and M2 macrophages (P=0.0043) increased significantly after IR. M1 macrophages also showed an increasing trend, but there was no statistically significant difference. In addition, further verification of changes in several proteins on the JAK/STAT pathway by IHC. The results showed that overall macrophages (P=0.0087) and M1 macrophages (P=0.026), PD-L1 (p=0.003), JAK1 (p=0.021) and STAT3 (p=0.018) were significantly increased after IR compared with before IR. M2 macrophages and STAT1 (p=0.734) also showed an increasing trend, but there was no statistically significant difference. It is worth noting that Kendall's tau-b correlation analysis was used to study the correlation of protein changes. The results found that the changes in PD-L1 expression before and after radiotherapy were related to STAT3 (Kendall's tau-b=0.487, P=0.02), JAK1 (Kendall's tau-b=0.513, P=0.015), there is a strong positive correlation. Conclusions: This study found that IR affects changes in cervical cancer TIME and these changes may promote the transition to an immunosuppressive phenotype. In addition, IR may affect changes in PD-L1 levels through the JAK1/STAT3 pathway. This needs to be further verified by designing large prospective clinical trials in the future.

Genomic characteristics of exceptional responders to treatment with PD-1 inhibitors in refractory/metastatic head and neck squamous cell carcinoma.

6062 Background: With the emergence of immune checkpoint inhibitors (ICIs), there are patients with advanced cancers experiencing exceptional treatment response with overall low treatment-associated toxicities. Despite success in refractory/metastatic head and neck squamous cell carcinoma (HNSCC), only a portion of patients experience benefit from the treatment with ICIs. Critical information on predictors of patient’s response to treatment is limited. At our institution we analyzed the genomic profiles of 36 patients with advanced HNSCC who demonstrated an exceptional response to treatment with PD-1 inhibitors. Methods: We reviewed patients with histologically confirmed HNSCC that had been treated with PD-1 inhibitors at Atrium Health Wake Forest Baptist Health. Treatment regimen included pembrolizumab 200mg every 3 weeks or nivolumab 240mg every 2 weeks. Response to therapy and duration of remission were monitored via CT scans and/or MRI scans at 3-month intervals, using RECIST 1.1 criteria. Exceptional responders were defined as achieving complete response (CR) or partial response (PR) for greater than six months, or stable disease (SD) for greater than one year. Progression free survival (PFS) and overall survival (OS) were measured from the date of PD-1 inhibitor initiation. PD-L1 level was measured via FoundationOne immunohistochemistry staining and reported as combined positive score (CPS). Additionally, next generation sequencing was performed on tumor (30/36 patients) and blood (33/36 patients) specimens via FoundationOne and Guardant360 testing platforms. Results: Out of 155 HNSCC patients treated with a PD-1 inhibitor, 36 patients demonstrated an exceptional response as defined above. 20 with CR, 9 with PR and 7 with SD. With an average follow up of 32 mo (95% CI, 26 mo-ongoing), the average OS was 33 mo (95% CI, 28 mo–ongoing) and the average PFS was 25 mo (95% CI, 20 mo-ongoing). These patients underwent an average of 27 treatments (range, 10-64 treatments to date). PD-L1 average score at 36 (95% CI, 22-49) and average TMB at 19 mut/mb (range, 0-90 mut/mb). Of 290 detected gene mutations, the most frequently mutated genes were TP53 (75%), PIK3CA (42%), CDKN2A (36%), EGFR (33%), TERT (25%), BRCA2 (22%), ERBB2 (22%), HNF1A (22%), MLL2 (22%), NOTCH1 (22%), and RAD21 (22%). Conclusions: There is limited data reporting the genomic profile of exceptional responders to PD-1 inhibitors in refractory/metastatic HNSCC. Higher TMB and single gene mutations such as TP53, PIK3CA, CDKN2A, EGFR, and TERT are frequently detected in exceptional responders and may provide future direction into the investigation of predictors of response to ICIs.

Are the results of clinical trials in patients with NSCLC reflected in real life? The Registurk-Lung study.

e20512 Background: Evaluation of real-world data together with data in clinical studies is very important in the evaluation of treatment algorithms. In real life, treatments are applied to the elderly, patients with poor performance and unusual groups with comorbidities. Determining these treatment results is important in the creation of treatment algorithms. Methods: In our country, within the scope of the Registurk-Lung observational study (NCT05254119), a total of 4250 patients without driver mutation, metastatic non-small cell lung cancer were recorded between December 2021 and December 2023 in 42 centers representing the whole country. The demographic, histopathological, molecular and clinical data of the patients were recorded. The relationship between progression-free survival (PFS) time and overall survival (OS) time with these characteristics was investigated. Results: 4250 patients were evaluated. The median age was 64 (26-90) years and 15.1% of the patients were female. The proportion of patients who never smoked was 10.4 %. Histopathologically, 36.4% of the patients were diagnosed with squamous cell carcinoma. PDL-1 level was higher than 50% in 24.0% of patients and < 1 in 40.4% of patients. Only 11.8 percent of patients received single agent immunotherapy or chemoimmunotherapy. Other patients had received only a combination of doublet chemotherapy. The PFS was 6.9 months (95% CI: 6.4-7.3) and OS 14.6 (95% CI: 12.3-16.8) months in the whole patient group. Compared to the group that received chemotherapy alone, PFS and overall survival were longer in the group that received chemoimmunotherapy. This difference between the two groups was found to be statistically significant (p:0,001 and 0,031 respectively). Conclusions: As shown in clinical studies, immunotherapy alone or chemoimmunotherapy according to PDL-1 expression status provides a significant survival contribution compared to chemotherapy alone.

Prediction of pCR with pretreatment MRI radiomics in triple negative breast cancer treated with neoadjuvant chemo-immunotherapy.

589 Background: Neoadjuvant chemo-immunotherapy (NACI) has become the new standard of care for stage II-III triple-negative breast cancers (TNBC). This approach is linked to high rates of pathological complete responses (pCR), yet factors influencing responses to this regimen remain poorly characterized. Our objective was to investigate whether pretreatment MRI perfusion-based radiomics could serve as a predictive tool for pCR to NACI in patients with TNBC. Methods: This prospective study enrolled women with early-stage TNBC undergoing NACI at two different centers from August 2021 to July 2023. Tumor segmentation and pharmacokinetic analyses of pretreatment multi-vendor dynamic-contrast-enhanced (DCE)-MRI were conducted using the standard perfusion Tofts model. Radiomics features were extracted from the Ktrans, Ve, and Slopemax maps. Unsupervised correlation analysis of reproducible features and least absolute shrinkage and selector operation were employed to construct a radiomics score. The performance of the radiomic score was evaluated using the area under the receiver operating characteristic curve (AUC). A multivariable logistic regression model was employed to establish a multimodal nomogram. Performance metrics included discrimination, calibration, and clinical usefulness, assessed on the external validation set. Results: The training set comprised 112 patients from center 1 (mean age, 52 years ± 11 [SD]), and the external validation set included 83 participants from center 2 (mean age, 49 years ± 11 [SD]). Overall, the pCR rate was 70% (137/195). In the validation set, the radiomic score achieved an AUC of 0.80 (95% CI: 0.70, 0.89) for predicting pCR. A nomogram incorporating the radiomics score, tumor grade, and Ki67 yielded an AUC of 0.86 (95% CI: 0.78, 0.94) and demonstrated superior predictive efficacy compared to the histological prediction model (AUC, 0.76 [95% CI: 0.66, 0.87]; P = .02) in the validation set. Calibration curves of the nomogram exhibited good concordance between predicted and observed pCR in both sets. The radiomic score correlated with tumor size, washout enhancement curve, androgen receptor (AR), and combined positive score (CPS) PD-L1 levels (all P < 0.05). Conclusions: PretreatmentMRI-based radiomics is a reliable predictor of pCR to NACI and might help customizing treatment choice for early-stage TNBC patients.

Association of combination tumor texture and vessel tortuosity with progression free survival across PD-L1 subgroups in durvalumab treated non-small cell lung cancer (NSCLC): Blinded validation results from CP1108.

8600 Background: Immunotherapy (IO) has shown a durable response with minimal toxicity in the treatment of metastatic NSCLC. However, only 30-50% of these patients (pts) actually respond. Despite initial optimism surrounding PD-L1 expression as a potential biomarker, IO provides benefit across PD-L1 low (<25%) and high (≥25%) status. This highlights a critical need for more effective biomarkers to guide treatment decisions. Here, we present blinded validation results of a CT-based biomarker of change in quantitative vessel tortuosity (1) (Δ-QVT) and texture radiomics (2) (Δ-Rad) between baseline (B) and 6 weeks post-treatment (TP1) for predicting response, overall survival (OS) and progression free survival (PFS) in CP1108 (NCT01693562). Methods: CT scans at B and TP1 were retrospectively analyzed from two studies (a) a multi-center training set (Str, N=110) of metastatic NSCLC pts treated with first line IO and (b) a blinded NSCLC cohort of N = 151 pts treated with Durvalumab in CP1108 study (Sv). In Sv, N=75 pts were PD-L1 high (Sv+) whereas N=65 pts were PD-L1 low (Sv-). An in-house MATLAB based algorithm was used to extract intra-tumoral, peri-tumoral texture and QVT features from up to two largest measurable tumors in each CT. A classifier (MCombo) was trained on Str to predict best overall response defined as per the RECIST v1.1 criteria using combination of Δ-QVT and Δ-Rad features. Area under the receiver operating characteristic (AUC) was used to evaluate MCombo against RECIST response whereas univariable and multivariable Cox regression models with log-rank test, hazard ratio (HR) with confidence interval (CI) and concordance index (C-index) were used to study the association of MCombo with OS and PFS in Sv, Sv+, and Sv-. Results: MCombo predicted objective response with an AUC of 0.78 in Sv and was statistically significantly associated with PFS (Table) in Sv, Sv+, and Sv-. MCombo was associated with OS in Sv, Sv+, but not in Sv-. Multivariable analysis with PD-L1 status, histological subtype, ECOG status, liver metastasis, line of therapy and sex showed independent association of MCombo across OS and PFS. Conclusions: Our results indicate that combination of radiomics and vessel tortuosity biomarker from CT is independently prognostic of response and PFS across PD-L1 levels. Prospective validation of this biomarker is needed. 1. Alilou et al. Sci Adv 2022. 2. Khorrami et al. Cancer Immunol Res 2020. [Table: see text]

Outcomes in STK11-, KEAP1-, and KRAS-mutant lung squamous cell carcinoma (LSCC) with use of immune checkpoint inhibitors (ICIs).

e20504 Background: Studies have suggested that STK11, KEAP1, and KRAS mutations impact response to ICIs in individuals with lung adenocarcinoma. The effect of these mutations in LSCC is unknown. Methods: We conducted a retrospective analysis from January 1, 2018 through December 31, 2023 evaluating individuals seen in the Indiana University Health System with STK11, KEAP1, or KRAS-mutant advanced LSCC treated with ICI-based therapy. Demographic information and baseline PD-L1 levels were collected. Response to therapy was assessed using standardized real-world criteria. Progression-free survival (PFS) was calculated using the Kaplan-Meier method and compared using a log-rank test. Results: Thirty-one of 316 evaluable patients with LSCC had a mutation in KEAP1, STK11, or KRAS. Twenty-one of those individuals had advanced disease treated with ICIs. Nine of 21 had tumors harboring KEAP1 and/or STK11, 10 had tumors harboring KRAS, and 2 had KRAS + STK11-mutant tumors. The median age was 67 years, 71% (15/21) were male, 86% (18/21) were White, 83% (15/18) had PD-L1 levels ≥1%, and 81% (17/21) were evaluable for response including 11 treated with ICIs + chemotherapy and 6 who received ICIs alone. The overall response rate (ORR) was 65% with 5 individuals having progressive disease (PD), 1 with stable disease (SD), and 11 exhibiting partial response (PR). Those receiving ICIs + chemotherapy had an ORR of 73% (3 PD, 8 PR). The ORR was 50% (2 PD, 1 SD, 3 PR) in the cohort treated with ICIs alone. Among those with KEAP1 and/or STK11 mutations, the ORR was 43% (4 PD, 3 PR). The ORR was 88% for the KRAS-mutant cohort (1 SD, 7 PR) and 50% in the KRAS + STK11 subgroup (1 PD, 1PR). The median PFS was 6.4 months for the entire population, 6.0 months for those treated with ICIs + chemotherapy, and 8.1 months for those receiving ICIs alone. Although the cohort size was limited, individuals with KRAS mutations appeared to have improved PFS compared to those with STK11, KEAP1, or KRAS + STK11 mutations treated with ICI-based therapy (Table 1). Conclusions: STK11, KEAP1, and KRAS mutations impact response to ICIs in individuals with LSCC. There was a trend toward improved ORR and PFS in those with KRAS-mutant LSCC treated with ICI-based therapy compared to those with STK11, KEAP1, or KRAS + STK11-mutations. [Table: see text]

Effect of simvastatin on PD-L1 via ILF3 to enhance CD8+ T cell-mediated ferroptosis in gastric cancer cells.

e16056 Background: Immunotherapy is vital in the comprehensive treatment of gastric cancer (GC). However, the prognosis of GC patients remains unfavorable, necessitating to exploration of novel therapeutic approaches and medications. Methods: PD-L1 expression was observed using small interfering RNA and plasmid to knock down and overexpress ILF3, respectively. The expression of ILF3, PD-L1, and ferroptosis marker molecules (SLC7A11 and GPX4) was detected upon simvastatin stimulation of gastric cancer cells co-cultured with activated CD8+ T cells. To assess the impact of ILF3 and simvastatin stimulation on the induction of ferroptosis in gastric cancer cells by CD8+ T cells, various assays including CCK8, MTT, ROS, Fe2+, MDA, GSH, and LPO were conducted. Cleavage under targets and Tagmentation (CUT&Tag) was employed to validate the mechanism of simvastatin by regulating ILF3 expression. Whole genome sequencing and KEGG analysis reveal that ILF3 regulates PD-L1 expression through the DEPTOR/mTOR signaling pathway. Results: Statin treatment decreased the serum levels of ILF3 and PD-L1. This study found that ILF3 was positively correlated with the expression of PD-L1, and the knockdown of ILF3 effectively inhibited the expression of PD-L1, thus enhancing the cytotoxicity of CD8+ T cells to gastric cancer cells. Meanwhile, simvastatin inhibited the expression of PD-L1 through ILF3, which enhanced the induction of ferroptosis in gastric cancer cells by CD8+ T cells. Further studies found that simvastatin inhibited ILF3 expression by decreasing the acetylation level at residue site H3K14 in ILF3, while ILF3 inhibited PD-L1 expression through the DEPTOR/mTOR pathway. Conclusions: Simvastatin further recruited CD8+ T cells to enhance anti-tumor immunity by inhibiting PD-L1 expression by ILF3 and induced GC cells to undergo ferroptosis to achieve synergistic immunotherapy. This study elucidated the new mechanism of statins to improve GC immunotherapeutic effect. It revealed a new theoretical basis for using statins in GC treatment to improve the prognosis of GC patients.

PD-L1 and alternative immune checkpoints (AICs) in non-small cell lung cancer (NSCLC): Insights into the tumor immune microenvironment (TIME) and immunotherapy (IO) outcomes.

8531 Background: PD-L1 and recently identified AICs (B7x, B7-H3, and HHLA2) may function as key immune evasion mechanisms in NSCLC and influence IO efficacy. This study explores the expression patterns of PD-L1 and AICs within the TIME and their impact on IO outcomes in NSCLC, including key molecular subtypes. Methods: NSCLC samples (n=27,629) were analyzed (Caris Life Sciences) with NextGen Sequencing on DNA (592 genes or whole exome)/RNA (whole transcriptome). Tumor cell PD-L1 expression (22c3) was assessed by IHC. Gene expression profiles were analyzed for IFN-γ score and QuantiSEQ was used to assess immune cell infiltration in the TIME. Real-world overall survival (rwOS: from time of biopsy to last contact), time on treatment [TOT: from the first pembrolizumab (pembro) treatment to the last], and OS on pembro (OSpem: from pembro start to last contact) were calculated. Mann-Whitney U, X2/Fisher-Exact, and log-rank tests were applied where appropriate. Results: PD-L1 IHC+ NSCLC and cases with high PD-L1 RNA expression had higher IFN-γ score and immune cell fractions (p<0.0001 for both) vs PD-L1 IHC- and low expression, respectively. Additionally, PD-L1 IHC+ NSCLC was associated with (a/w) higher median transcript levels (TPM) of PD-L1 and B7-H3, while PD-L1 IHC- NSCLC was a/w higher TPM of HHLA2 and B7x (p<0.0001 for all). AICs expression varied by molecular subtype, e.g., higher HHLA2/B7x RNA in EGFR mutant vs wild-type (WT) NSCLC. Moreover, PD-L1 IHC+ NSCLC and cases with high PD-L1 RNA and low B7H3 RNA were a/w longer rwOS, OSpem, and TOT; high HHLA2 RNA was a/w longer rwOS and OSpem with similar TOT; and low B7x RNA expression was a/w longer OSpem and TOT with similar rwOS (Table). Conclusions: Both PD-L1 IHC+ NSCLC and cases with high PD-L1 RNA expression are a/w a more inflammatory TIME, and superior survival and IO outcomes. Moreover, consistent with our prior HHLA2 IHC work (PMIDs: 27553831, 29374053), HHLA2 RNA expression was significantly higher in PD-L1 IHC- and EGFR mutant cases. These findings support the potential utility of transcriptomics along with protein expression for assessing novel predictive biomarkers for IO. Furthermore, the distinct expression profiles of AICs identified in our study may represent key subtypes mediating IO response in WT and EGFR mutant NSCLC. [Table: see text]

Association of tumor-infiltrating lymphocytes (TILs) and immune signatures with PAM50 intrinsic subtyping hormone receptor-positive (HR+)/HER2-negative (HER2-) early breast cancer (BC): A translational analysis of two multicentric neoadjuvant trials.

558 Background: HR+/HER2− BCs are generally described as immunologically cold, with low levels of TILs and PD-L1. Nevertheless, the addition of immunotherapy (ICI) to chemo has been reported to increase pCR rates in high-risk early HR+/HER2– BCs. Assessing the interaction between immune features and tumor biology may identify of a subset of patients (pts) with HR+/HER2− BC that would be the ideal candidates for the combination of chemo and ICI. Methods: Gene-expression data from two multicentric neoadjuvant phase II trials (GIADA, LETLOB) enrolling stage II-IIIA HR+HER2- BC pts was retrieved (Dieci, CCR 2022; Guarneri, JCO 2014). In the GIADA trial, 758 genes were assessed on baseline tumor samples by nCounter (N=43). In the LETLOB trial, gene-expression data (Affymetrix platform) from baseline core-biopsies was available for 66 pts. Intrinsic subtype was assigned using a research-based PAM50 predictor. TILs were evaluated following guidelines. Association of TILs and immune signatures with intrinsic subtyping was assessed by Kruskal-Wallis test. Results: PAM50 subtype distribution (N=109) was 44% Luminal B (LumB), 33% Luminal A (LumA), 18% Basal-like, 5% HER2-enriched (HER2-E). TILs were assessed on 101 samples: median 2 (range 0-100). Basal-like BCs showed higher TILs than other subtypes (p=0.008). No significant difference was observed between LumA and LumB BCs (Table). Basal-like tumors showed higher levels of previously published immune signatures associated with CD8 T-cells (p<0.001), Cytotoxic cells (p<0.001), IFN-gamma (p<0.001), and response to ICI in the GeparNuevo trial (p=0.003) (N=109). PD-1 (p=0.002), PD-L1 (p=0.001), and PD-L2 (p=0.001) genes were also more expressed in Basal-like BCs (evaluable in 43 samples). No significant difference was observed between LumA and LumB tumors. A significant weak to moderate positive correlation was observed between continuous TILs and immune signatures and basal-like PAM50 signature (p<0.001, Spearman coefficient=0.372 for TILs, from 0.354 to 0.648 for immune signatures). Conclusions: PAM50 intrinsic subtyping and TILs/immune signatures capture only partially overlapping information on the biology of HR+/HER2- BCs. Pts with HR+/HER2- BCs simultaneously showing features of biological aggressiveness and enhanced immunogenicity may represent the ideal candidates for the combination of ICI and chemo. [Table: see text]

A phase II, multicenter, open-label study of polyPEPI1018 in combination with atezolizumab in participants with relapsed or refractory microsatellite-stable metastatic colorectal (MSS mCRC) cancer (Oberto-301).

3594 Background: The efficacy of checkpoint inhibitor immunotherapy in MSI-H mCRC has not been replicated in MSS mCRC. Therefore, additional interventions are needed to convert immunologically “cold” MSS CRC to “hot” tumors resembling MSI-H tumors. PolyPEPI1018 is an off-the-shelf, multi-peptide vaccine containing 12 immunogenic epitopes derived from 7 shared tumor antigens which demonstrated early evidence of clinical activity in first-line MSS mCRC. Methods: Patients with MSS mCRC who have progressed on 2-3 lines of prior chemotherapy regimen received PolyPEPI1018 (1.2 mg, sc) and atezolizumab (1,200 mg, iv) Q3W until disease progression or unacceptable toxicity. The primary endpoint was safety. A Simon 2-stage design was applied. Data on objective response rate (ORR), disease control rate (DCR), progression-free survival (PFS), overall survival (OS) and correlation studies will be presented. Results: 18 patients (66 % female) were enrolled for stage 1 of the study. Median age was 54 years (range 38–79), 50% had liver metastases and 67% received at least 3 lines of prior therapies. PD-L1 expression was <1% for 85% of patients. The combination was well-tolerated; most common side effect related to treatment was Grade (Gr) 1-2 local skin reaction (n=22). Gr 2 events (n=2) at least possibly related to treatment were nausea, pyrexia and increased blood alkaline phosphatase. There were no Gr 3-5 events or study discontinuation due to treatment AE. The ORR was 0% and the DCR was 61%. The mPFS was 2.7 months (95%CI 1.4-4.0) and the mOS was not reached (95%CI 8.75 – NE months) at the data cut-off date. Ex-vivo FluoroSpot identified 13/16 subjects with robust, vaccine-specific CD8+ and/or CD4+ T cell responses detected against multiple vaccine antigens. For patients with available biopsy pairs (n=8), both the average PD-L1 expression (IC%, p=0.029) and the density of CD8+ tumor-infiltrating lymphocytes (TILs, p=0.019) were significantly increased, post-treatment. Patients with increased PFS (> 12 weeks) had both higher levels of post-treatment PD-L1 (p=0.007) and TILs (p=0.016) than patients with PFS ≤ 12 weeks. Conclusions: PolyPEPI1018 in combination with atezolizumab was well-tolerated with no Grade 3 AEs observed. Despite no objective tumor responses could be detected, correlative data suggest contribution of PolyPEPI1018-induced immune responses to the modulation of tumor microenvironment and to improved disease control. The study did not proceed to stage 2; it is on-going for the collection of survival data. Clinical trial information: NCT05243862 .

Pediatric primary extragonadal choriocarcinoma - A study on male patients at a single tertiary medical institution

BackgroundPrimary extragonadal choriocarcinoma (PEGCC) in male is rare. It is highly malignant, typically presents with distant metastasis at the time of diagnosis, and responds poorly to treatment. Because of its associated high levels of PD-L1, the PD-1/PD-L1 pathway is a likely therapeutic target. Herein, we report our experience of treating pediatric PEGCC in six boys at a tertiary hospital. MethodsWe analyzed the data of six boys with pathologically confirmed PEGCC between 2009 and 2021. Their clinicodemographic and histopathological characteristics as well as treatments and clinical outcomes were retrieved from their medical charts. ResultsThe patients' median age was 15 (range: 12–17) years. The most common primary tumor site was the mediastinum (67%, 4/6), with one case each in the retroperitoneum (16.7%) and brain (16.7%). Except for the patient with brain PEGCC, all presented with metastasis at the time of diagnosis. The following metastatic sites were observed: the lungs (100%, 5/5), brain (3/5, 60%), liver (3/5, 60%), kidneys (2/5, 40%), and spleen (1/5, 20%). Most patients had dry cough, dyspnea, and hemoptysis at initial presentation, likely due to lung metastasis. Serum human chorionic gonadotropin (HCG) levels were highly elevated in all patients. All patients received platinum-based cytotoxic chemotherapy. The patient with brain choriocarcinoma underwent surgical tumor resection; all others underwent only surgical biopsy. Strong positive PD-L1 immunohistochemical staining was noted for two patients. One patient received the PD-L1 inhibitor pembrolizumab and achieved a good response. Our cohort's 1-year survival rate was 33.3%, with a median survival of 4.34 months. Serum HCG levels remained normal in the two survivors during follow-up visits. ConclusionThe poor response to current platinum-based chemotherapy remains a major challenge in the management of pediatric PEGCC. Adding pembrolizumab to a conventional chemotherapy regimen may improve the outcomes in boys with PEGCC.

A phase 1, open-label, dose escalation study on the safety and tolerability of ANK-101 in advanced solid tumors.

TPS2689 Background: IL-12 is a cytokine that can stimulate both innate and adaptive tumor immunity. Clinical trials of intravenous IL-12 demonstrated anti-tumor activity limited by significant systemic toxicity, including patient deaths. ANK-101 is an anchored immunotherapy that links IL-12 to aluminum hydroxide through an alum-binding protein (ABP). The ANK-101 complex anchors IL-12 in the tumor microenvironment (TME), resulting in prolonged local retention and low levels of systemic absorption. Preclinical studies in murine tumor models showed that ANK-101 is retained at the injection site for up to 28 days, recruits and activates T and NK cells, promotes M1 myeloid cell differentiation, induces regression of both injected and un-injected tumors, and induces immunologic memory. Methods: This is a first-in-human, open-label dose escalation study of ANK-101 in advanced solid tumors with a planned sample size of 12-36 participants. The first three dose escalation cohorts include a single participant, and then study enrollment follows a standard 3+3 dose escalation design. If no dose limiting toxicity (DLT) is observed, the dose level will be escalated until ≥1/3 or ≥2/6 patients experience a DLT. An additional ten patients will be enrolled at the recommended dose for expansion (RDE). Participants will be treated with intratumoral ANK-101 every 3 weeks for 4 cycles. Imaging or clinical assessments will be performed at week 12. If there is no significant clinical deterioration or unacceptable toxicity at this visit, participants may receive four more cycles. Eligible patients must have an advanced solid malignancy refractory to standard treatment and be accessible for injection and biopsy, measurable disease by RECIST v1.1, and ECOG PS of 0-1. Key exclusion criteria include tumors close to vital structures, uncontrolled bleeding disorders, and active autoimmune disease. Primary objectives of the study are to determine the safety and tolerability of ANK-101 and identify the RDE. Secondary objectives include pharmacokinetics (PK) and immunogenicity (ADA) of ANK-101 and clinical activity as measured by ORR, DCR, DOR and PFS by RECIST v1.1. Exploratory objectives include assessment of QOL using FACT-G and profiling immune-based pharmacodynamic (PD) changes. PD assessments will include serum cytokines and circulating immune cells, and local levels of PD-L1, CD8+ T cells, and CD68+ macrophages, and changes in gene expression within the TME. This clinical trial is in progress. Clinical trial information: NCT06171750 .

Possibilities of long-term atezolizumab immunotherapy in patients with metastatic urothelial cancer.

e14628 Background: Results from various studies have indicated that atezolizumab can be an effective and well-tolerated treatment option for patients with advanced and metastatic urothelial cancer. However, the landscape of oncological practices in Uzbekistan reflects a scarcity of experience and data concerning the utilization of atezolizumab in the treatment of patients afflicted with urothelial cancer. This research endeavors to bridge this gap by contributing. Methods: In our retrospective study, a total of 44 patients were selected, with a mean age of 64.5±7.6 years, diagnosed with stage IV urothelial cancer and the presence of distant metastases in the lungs, bones, and liver. There were 28 (63.6%) males and 16 (36.4%) females. Group 1 included 18 (40.9%) patients with elevated PD-L1 levels SP142 – IC 2/3, receiving atezolizumab at 1200 mg intravenously (IV) on day 1 of each 21-day cycle + cisplatin at a dose of 70 mg/m2 body surface area (BSA), IV, on day 1 of each cycle, and gemcitabine at a dose of 1000 mg/m2 BSA, IV, on days 1 and 8 of each cycle. Group 2 included 26 (59.1%) patients receiving standard chemotherapy (cisplatin + gemcitabine) in the same regimens. Immunohistochemical analysis was performed using the Ventana Bench Mark Ultra automated stainer with Ventana PD-L1 SP142 monoclonal antibodies. Results: The research was conducted from September 2019 to May 2023, and the administered treatment was the first line for these patients. Treatment was administered until disease progression was registered or until the development of unacceptable toxicity. Grade I toxicity was not observed in both groups. Grade II toxicity in Group 1 was noted in 3 (16.7%), and in Group 2 - in 4 (15.4%). Grade III toxicity was identified in 9 patients (50.0%) in Group 1 and 14 patients (53.8%) in Group 2. Grade IV toxicity was encountered in 6 patients (33.3%) in Group 1 and 8 patients (30.8%) in Group 2. Hematological toxicity, regardless of atezolizumab use, predominated among the III and IV degrees of toxicity. The median overall survival in Group 1 was 14.8 months (95% CI: 12.8-16.2), while in Group 2, it was 11.9 months (95% CI: 9.3-13.5). Progression-free survival in Group 1 was 6.8 months (95% CI: 5.1-7.4), and in Group 2, it was 4.3 months (95% CI: 3.8-5.7). The objective response rate in Group 1 was 44.5%, and in Group 2, it was 38.5%. Conclusions: Atezolizumab, used in combination with standard platinum-based chemotherapy in the first line, improves treatment outcomes for metastatic urothelial cancer by increasing overall survival and progression-free survival without causing an increase in the toxicity of the administered therapy.

Dual-Recognition-Mediated Autocatalytic Amplification Assay for the Subpopulations of PD-L1 Positive Extracellular Vesicle.

The PD-L1 protein on extracellular vesicles (EVs) is a promising biomarker for tumor immunotherapy. However, PD-L1+ EVs have various cell origins, so further analysis of the subpopulations is essential to help understand better their relationship with tumor immunotherapy. Different from the previous work which focus on the level of total PD-L1+ EVs expression, we, herein, report a dual-recognition mediated autocatalytic amplification (DRMAA) assay to detect the PD-L1 derived from tumors (EpCAM+), immune T cells (CD3+), and total (Lipids) EVs, respectively. The DRMAA assay employed proximity hybridization to construct a complete trigger sequence and then catalyzed the cross-hybridization of three hairpin probes, producing a three-way DNA junction (3-WJ) structure carrying the newly exposed trigger sequence. The 3-WJ complex subsequently initiated an autocatalytic amplification reaction and higher sensitivity than the traditional catalytic hairpin assembly assay was obtained. It was found that the EpCAM+ and PD-L1+ EVs were more effective than others in distinguishing lung cancer patients from healthy people. Surprisingly, the CD3+ and PD-L1+ EVs in lung cancer patients were also upregulated, indicating that immune cell-derived PD-L1+ EVs are also non-negligible marker in a tumor microenvironment. Our results suggested that the DRMAA assay would improve the study of subpopulations of PD-L1+ EVs to provide new insights for cancer immunotherapies.

DRG2 is required for surface localization of PD-L1 and the efficacy of anti-PD-1 therapy.

More than half of tumor patients with high PD-L1 expression do not respond to anti-PD-1/PD-L1 therapy, and the underlying mechanisms are yet to be clarified. Here we show that developmentally regulated GTP-binding protein 2 (DRG2) is required for response of PD-L1-expressing tumors to anti-PD-1 therapy. DRG2 depletion enhanced IFN-γ signaling and increased the PD-L1 level in melanoma cells. However, it inhibited recycling of endosomal PD-L1 and reduced surface PD-L1 levels, which led to defects in interaction with PD-1. Anti-PD-1 did not expand effector-like T cells within DRG2-depleted tumors and failed to improve the survival of DRG2-depleted tumor-bearing mice. Cohort analysis revealed that patients bearing melanoma with low DRG2 protein levels were resistant to anti-PD-1 therapy. These findings identify DRG2 as a key regulator of recycling of endosomal PD-L1 and response to anti-PD-1 therapy and provide insights into how to increase the correlation between PD-L1 expression and response to anti-PD-1 therapy.

A digital microfluidic device integrated with electrochemical sensor and 3D matrix for detecting soluble PD-L1

PD1/PD-L1 checkpoint inhibitors are at the forefront of cancer immunotherapies. However, the overall response rate remains only 10–30%. Even among initial responders, drug resistance often occurs, which can lead to prolonged use of a futile therapy in the race with the fatal disease. It would be ideal to closely monitor key indicators of patients’ immune responsiveness, such as circulating PD-L1 levels. Traditional PD-L1 detection methods, such as ELISA, are limited in sensitivity and rely on core lab facilities, preventing their use for the regular monitoring. Electrochemical sensors exist as an attractive candidate for point-of-care tool, yet, streamlining multiple processes in a single platform remains a challenge. To overcome this challenge, this work integrated electrochemical sensor arrays into a digital microfluidic device to combine their distinct merits, so that soluble PD-L1 (sPD-L1) molecules can be rapidly detected in a programmed and automated manner. This new platform featured microscale electrochemical sensor arrays modified with electrically conductive 3D matrix, and can detect as low as 1 pg/mL sPD-L1 with high specificity. The sensors also have desired repeatability and can obtain reproducible results on different days. To demonstrate the functionality of the device to process more complex biofluids, we used the device to detect sPD-L1 molecules secreted by human breast cancer cell line in culture media directly and observed 2X increase in signal compared with control experiment. This novel platform holds promise for the close monitoring of sPD-L1 level in human physiological fluids to evaluate the efficacy of PD-1/PD-L1 immunotherapy.

Statins inhibit paclitaxel-induced PD-L1 expression and increase CD8+ T cytotoxicity for better prognosis in breast cancer.

In recent years, the widespread use of lipid-lowering drugs, especially statins, has attracted people's attention. Statin use may be potentially associated with a reduced risk of breast cancer. To explore the relationship between statin use and cancer risk. And further explore the potential role of statins in the adjuvant treatment of breast cancer. Data for the Mendelian randomization portion of the study were obtained from genome-wide association studies of common cancers in the UK Biobank and FinnGen studies and from the Global Lipid Genetics Consortium's low density lipoprotein (LDL). In addition, the impacts of statins and chemotherapy drugs on breast cancer were examined using both in vitro and in vivo models, with particular attention to the expression levels of the immune checkpoint protein PD-L1 and its potential to suppress tumor growth. Data from about 3.8 million cancer patients and ~1.3 million LDL-measuring individuals were analyzed. Genetically proxied HMGCR inhibition (statins) was associated with breast cancer risk reduction (P=0.0005). In vitro experiments showed that lovastatin significantly inhibited paclitaxel-induced PD-L1 expression and assisted paclitaxel in suppressing tumor cell growth. Furthermore, the combination therapy involving lovastatin and paclitaxel amplified CD8+ T-cell infiltration, bolstering their tumor-killing capacity and enhancing in vivo efficacy. The utilization of statins is correlated with improved prognoses for breast cancer patients and may play a role in facilitating the transition from cold to hot tumors. Combination therapy with lovastatin and paclitaxel enhances CD8+ T-cell activity and leads to better prognostic characteristics.

Effective delivery of anti-PD-L1 siRNA with human heavy chain ferritin (HFn) in acute myeloid leukemia cell lines.

Because of the high biocompatibility, self-assembly capability, and CD71-mediated endocytosis, using human heavy chain ferritin (HFn) as a nanocarrier would greatly increase therapeutic effectiveness and reduce possible adverse events. Anti-PD-L1 siRNA can downregulate the level of PD-L1 on tumor cells, resulting in the activation of effector T cells against leukemia. Therefore, this study aimed to produce the tumor-targeting siPD-L1/HFn nanocarrier. Briefly, the HFn coding sequence was cloned into a pET-28a, and the constructed expression plasmid was subsequently transformed into E. coli BL21. After induction of Isopropyl β-D-1-thiogalactopyranoside (IPTG), HFn was purified with Ni-affinity chromatography and dialyzed against PBS. The protein characteristics were analyzed using SDS-PAGE, Western Blot, and Dynamic light scattering (DLS). The final concentration was assessed using the Bicinchoninic acid (BCA) assay. The encapsulation was performed using the standard pH system. The treatment effects of siPD-L1/HFn were carried out on HL-60 and K-562 cancer cell lines. The RT-PCR was used to determine the mRNA expression of PD-L1. The biocompatibility and excretion of siPD-L1/HFn have also been evaluated. The expression and purity of HFn were well verified through SDS-PAGE, WB, and DLS. RT-PCR analyses also showed significant siRNA-mediated PD-L1 silencing in both HL-60 and K-562 cells. Our study suggested a promising approach for siRNA delivery. This efficient delivery system can pave the way for the co-delivery of siRNAs and multiple chemotherapies to address the emerging needs of cancer combination therapy.

Asiaticoside promoted ferroptosis and suppressed immune escape in gastric cancer cells by downregulating the Wnt/β-catenin pathway

BackgroundOur previous study has revealed that asiaticoside (AC) promotes endoplasmic reticulum stress and antagonizes proliferation and migration of gastric cancer (GC) via miR-635/HMGA1 axis. However, the effect and mechanism of AC on other progressions of GC, such as ferroptosis and immune escape, are still unknown. MethodsAGS and HGC27 cells were incubated with 1, 2 and 4 μM of AC for 24 h. Mice xenografted with AGS cells were intragastrically injected with AC. The effect and mechanism of AC on GC were determined by the measurement of the ferrous iron level, the ROS level and the glutathione peroxidase (GSH) content, flow cytometry, enzyme-linked immunosorbent assay (ELISA), immunohistochemistry and western blotting assays. ResultsAC increased the Fe2+ level and the ROS level, but decreased the expression of GPX4 and SLC7A11 and the GSH level. Besides, AC enhanced the percent of CD8+ T cells and the IFN-γ concentration, but reduced the PD-L1 expression and the IL-10 level. Mechanically, AC downregulated the relative levels of β-catenin, active-β-catenin, p-GSK3β/GSK3β, cyclin D1 and c-Myc in GC cells, which were rescued with the application of LiCl (an activator of Wnt/β-catenin pathway) in AGS cells. Moreover, activation of Wnt/β-catenin pathway by LiCl or the β-catenin overexpression inverted the effect of AC on ferroptosis and immune escape in GC cells. In vivo, AC treatment declined the tumor size and weight, the level of GPX4, SLC7A11, PD-L1 and IFN-γ, and the expression of Wnt/β-catenin pathway. ConclusionAC enhanced ferroptosis and repressed immune escape by downregulating the Wnt/β-catenin signaling in GC.

Abstract PO1-25-03: Programmed Death-Ligand 1 and Receptor Tyrosine Kinases in Breast Cancer

Abstract Programmed death-ligand 1 (PD-L1) is an immune checkpoint expressed in a wide range of malignancies leading to immune tolerance and cancer cell immune evasion. Receptor tyrosine kinases (RTKs) are key regulators of cancer cell proliferation, survival, and invasion. The Hepatocyte Growth Factor (HGF) receptor, MET, and the Epidermal Growth Factor Receptor (EGFR) are RTKs known for their tumorigenic potential in a variety of human malignancies. This study aimed to evaluate the effect of the small-molecule tyrosine kinase inhibitors (TKIs) on the expression of PD-L1 in breast cancer cells and the effect of their combination with inflammatory cytokines. The study also assessed the association of the expression of the tumoral PD-L1 mRNA with each of MET and EGFR mRNA expression and the tumor features and treatment outcomes in breast cancer patients using the METABRIC dataset publicly available from cBioPortal for Cancer Genomics. The TKIs crizotinib [a MET inhibitor] and gefitinib [an EGFR inhibitor] were used as a single treatment and in combination with the cytokines; tumor necrosis factor-α (TNF-α) or interferon-γ (INF-γ) in MCF7 and MDA-MB-231 breast cancer cells in vitro. The cells were also treated with the mitogens HGF and EGF. The viability of cells after the different treatments was determined using the MTT viability assay. The effects of the combination treatments were analyzed using combination index (CI) analysis. The expression level of PD-L1 in cancer cells was assessed using Western blotting. The combination treatment of crizotinib with TNF-α and INF-γ produced a synergistic growth inhibition of MCF7 and MDA-MB-231 cells with CI values of 0.31 and 0.55, respectively. Alternatively, combined crizotinib and TNF-α produced an antagonist effect on the viability of MCF7 cells (CI=2.49). The combination of gefitinib with TNF-α produced a synergistic growth inhibition in both MCF7 and MDA-MB-231 cells with CI values of 0.39 and 0.78, respectively. Alternatively, gefitinib resulted in an additive effect when combined with INF-γ (CI=0.99) and an antagonistic effect when combined with TNF-α (CI=2.68) in MCF7 and MDA-MB-231 cells, respectively. Treatment with HGF (50 and 100 ng/ml) increased the protein levels of PD-L1 while EGF (50 and 100 ng/ml) reduced its levels in MDA-MB-231 cells. Treatment with the TKIs crizotinib (0.1-4 µM) and gefitinib (1-40 µM) significantly reduced PD-L1 levels in MDA-MB-231 cells compared to vehicle-treated cells. The analysis of the METABRIC dataset revealed that the mRNA expression of PD-L1 was positively correlated with the mRNA expression of the EGFR gene (r= 0.081, p< 0.001) but not the MET gene. A double-high PD-L1/MET expression was significantly associated with younger age at diagnosis, high-grade carcinoma, greater tumor size, hormone receptor-negative status, HER2-positivity, and non-luminal disease compared to patients with a double-low PD-L1/MET expression. Similar findings were reported for patients with a double-high PD-L1/EGFR expression compared to patients with a double-low PD-L1/EGFR expression. Nevertheless, the mRNA expression of the PD-L1, MET, and EGFR genes as well as the co-expression of PD-L1/MET or PD-L1/EGFR genes did not affect the overall survival of breast cancer patients. Collectively, MET and EGFR TKIs could modulate the effects of inflammatory cytokines differently based on the type of cytokine and the molecular subtype of breast cancer cells. The expression of PD-L1 in breast cancer cells was upregulated by HGF while TKIs reduced its expression. The co-expression of the PD-L1 gene with MET and EGFR genes in breast cancer was associated with advanced disease presentation and worse prognosticators in patients. Together, TKIs that target MET or EGFR could be an appealing therapeutic target in breast cancer, particularly in younger patients with the non-luminal disease. Citation Format: Nehad Ayoub, Muhsen Al-Diabat, Moath Al-Shorman, Laith Al-Eitan. Programmed Death-Ligand 1 and Receptor Tyrosine Kinases in Breast Cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO1-25-03.