Programmed Death Receptor Ligand Research Articles

Enhancement of anti-PD-L1 antibody plus anlotinib efficacy due to downregulation of PD-L1 in the micro-conduit endothelium within the tumor: a randomized double-blind trial.

The possible enhancing effect of anlotinib on programmed death receptor ligand (PD-L1) antibody and the efficacy-predicting power of PD-L1 in micro-conduit endothelium, including lymphatic endothelial cells (LECs) and blood endothelial cells (BECs), were determined to identify patients who would benefit from this treatment. PD-L1 positivity in LECs, BECs, and tumor cells (TCs) was assessed using paraffin sections with multicolor immunofluorescence in an investigator's brochure clinical trial of TQB2450 (PD-L1 antibody) alone or in combination with anlotinib in patients with non-small cell lung cancer. Progression-free survival (PFS) with different levels of PD-L1 expression was compared between the two groups. Among 75 patients, the median PFS (mPFS) was longer in patients who received TQB2450 with anlotinib [10 and 12 mg (161 and 194 days, respectively)] than patients receiving TQB2450 alone (61 days) [hazard ratio (HR)10 mg = 0.390 (95% confidence interval {CI}, 0.201-0.756), P = 0.005; HR12 mg = 0.397 (0.208-0.756), P = 0.005]. The results were similar among 58 patients with high PD-L1 expression in LECs and TCs [159 and 209 vs. 82 days, HR10 mg = 0.445 (0.210-0.939), P = 0.034; HR12 mg = 0.369 (0.174-0.784), P = 0.009], and 53 patients with high PD-L1 expression in BECs and TCs [161 and 209 vs. 41 days, HR10 mg = 0.340 (0.156-0.742), P = 0.007; HR12 mg = 0.340 (0.159-0.727), P = 0.005]. No differences were detected in the mPFS between the TQB2450 and combination therapy groups in 13 low/no LEC-expressing and 18 low/no BEC-expressing PD-L1 cases. Mono-immunotherapy is not effective in patients with high PD-L1 expression in LECs and/or BECs. Anlotinib may increase efficacy by downregulating PD-L1 expression in LECs and/or BECs, which is presumed to be a feasible marker for screening the optimal immune patient population undergoing anti-angiogenic therapy.

Sharks give a handle to potent anti-tumor multiparatopic antibodies inducing membrane depletion of PD-L1

Despite the immense clinical success of the antibody therapeutics that neutralize programmed death receptor ligand 1 (PD-L1) and thus resurrect Tcell antitumor activity, the patient response rates remain low. In this issue of Cell Chemical Biology, Ludwig etal.1 reveal novel topologies of multiparatopic antibodies that mediate potent PD-L1 downregulation.

Evaluation of markers of immunity in different metastatic immune microenvironments suggests more suppression within breast to liver metastases in breast cancer.

Programmed death receptor ligand-1 (PD-L1) expression and tumor mutational burden (TMB) are approved screening biomarkers for immune checkpoint inhibition (ICI) in advanced triple negative breast cancer. We examined these biomarkers along with characterization of the tumor microenvironment (TME) between breast tumors (BrTs), axillary metastases (AxMs), liver metastases (LvMs), non-axillary lymph node metastases, and non-liver metastases to determine differences related to site of metastatic disease. 3076 unpaired biopsies from breast cancer patients were analyzed using whole transcriptome sequencing and NextGen DNA depicting TMB within tumor sites. The PD-L1 positivity was determined with VENTANA PD-L1 (SP142) assay. The immune cell fraction within the TME was calculated by QuantiSeq and MCP-counter. Compared to BrT, more LvM samples had a high TMB (≥ 10 mutations/Mb) and fewer LvM samples had PD-L1+ expression. Evaluation of the TME revealed that LvM sites harbored lower infiltration of adaptive immune cells, such as CD4+, CD8+, and regulatory T-cells compared with the BrT foci. We saw differences in innate immune cell infiltration in LvM compared to BrT, including neutrophils and NK cells. LvMs are less likely to express PD-L1+ tumor cells but more likely to harbor high TMB as compared to BrTs. Unlike AxMs, LvMs represent a more immunosuppressed TME and demonstrate lower gene expression associated with adaptive immunity compared to BrTs. These findings suggest biopsy site be considered when interpreting results that influence ICI use for treatment and further investigation of immune composition and biomarkers expression by metastatic site.

Preclinical development of novel PD-L1 tracers and first-in-human study of [68Ga]Ga-NOTA-RW102 in patients with lung cancers

BackgroundThe programmed cell death protein-1 (PD-1)/programmed death receptor ligand 1 (PD-L1) axis critically facilitates cancer cells’ immune evasion. Antibody therapeutics targeting the PD-1/PD-L1 axis have shown remarkable efficacy in various...

OMA1 competitively binds to HSPA9 to promote mitophagy and activate the cGAS–STING pathway to mediate GBM immune escape

BackgroundImmunotherapy with checkpoint inhibitors, especially those targeting programmed death receptor 1 (PD-1)/PD-1 ligand (PD-L1), is increasingly recognized as a highly promising therapeutic modality for malignancies. Nevertheless, the efficiency of immune...

Frequency of Programmed Death Receptor Ligand 1 Expression and Clinicopathological Factors Associated With Metastatic Triple-Negative Breast Cancer at a Tertiary Cancer Care Centre in South India.

Purpose Triple-negative breast cancer (TNBC) has a poor outcome compared to other subtypes. Immune checkpoint inhibitors (ICIs) have changed the treatment paradigm in metastatic diseases as well as in neoadjuvant setting. The response to these agents is affected by programmed death ligand 1 (PDL1) receptor expression which are reported objectively as a score. PDL1 is a prognostic marker also. Here, we present clinicopathological characteristics of metastatic TNBCs, report the proportion of PDL1 expression and its association with clinicopathological factors as well as survival. Methods This is a prospective study carried out at a tertiary cancer care centre in South India. Case records of all breast cancer patients treated in two years between August 2021 and July 2023 were reviewed, patients with metastatic TNBC were selected. Patient's characteristics, histological features, molecular profile, and treatment were analyzed. PDL1 testing was carried out on pretreatment tumor tissue sections with immunohistochemistry (IHC) (Dako 22C3). PDL1 staining was interpreted as negative or positive based on combined positive score (CPS), with an expression less than 10 considered negative. Results A total of 118 patients were analyzed. With a median age of 46 years (36-65 years), 52.5% (62/118) were premenopausal. Family history of Ca Breast was seen in 22% (26/118) patients. A majority of patients had left-sided tumor 55.9% (66/118). Visceral metastasis was more common 96.6% (82/118) than skeletal. Radical intent of treatment was adopted in 10% as patients had oligometastatic disease at presentation. As front-line treatment, anthracycline-based chemotherapy was administered to the majority 54.2% (64/118). The PDL1 expression with CPS more or equal to 10 was seen in 32.2% (38/118) patients. Survival was associated with menopausal status (p value=0.000) and family history (p value=0.028) but notwith PDL1 nor sidedness in our study. Estimated survival at 12 months in PDL1 negative case is 10 ± 0.29 months, while in PDL1 positive case it is slightly more at 10± 0.75 months, but difference was not found to be statistically significant (p value=0.15). Conclusion TNBCs are highly aggressive subtype with limited treatment options and poorer outcomes. Our study shows PDL1 expression in 31.66% of the cases similar to other literature from India. Survival is associated with menopausal status and family history. No association was found between survival and PDL1 as well sidedness in our study.

Primary squamous cell carcinoma of the parotid salivary gland: a clinical observation

Introduction. Malignant tumors of the salivary glands account for 3–5 % of all cases of head and neck cancer. Squamous cell carcinoma is the rarest histological variant of this pathology. It accounts for an average of 1.6 %. Among large salivary gland tumors, squamous cell carcinoma most often occurs in the parotid salivary gland.Aim. To present a clinical case of primary disseminated cancer of the parotid salivary gland with squamous cell structure.Clinical observation. A 70-year-old patient was under observation who was diagnosed with a primary squamous cell tumor of the parotid salivary gland with multiple metastases during a complex examination. He was sick for about 6 months when asymmetry of left half of the face appeared due to a painful neoplasm in the parotid salivary gland. Recently, the patient has noted increased tumor growth. Objective examination revealed peripheral paralysis of the facial nerve on the left. In the parotid-masticatory region on the left, with a transition to the zygomatic region, there is a dense painful immobile exophytic tumor with infiltration into soft tissues of the face and skin 6.5 × 5.0 cm in size with an ulcer in the center. Laterally, it reaches the tragus, and at the bottom-the angle of the lower jaw. In the submandibular region on the left, metastatic lymph nodes 2.5 × 2.0 cm in size are palpated. A biopsy was collected. Histological conclusion: non-keratinizing squamous cell carcinoma. Expression of the programmed death receptor ligand (PD-L1) in the tumor is negative. Mutations of genes Her2-neu and BRAF were not detected. According to medical imaging methods, multiple metastases were found in the lungs, liver, zygomatic bone and tumor growth in the maxillary sinus on the left. The diagnosis was established: cancer of the parotid salivary gland, stage IVC, cT4N1M1, with metastases to the liver, lungs and bones. Polychemotherapy was prescribed according to the scheme: 5-fluorouracil + cisplatin + cetuximab + bisphosphonates. After 3 cycles, a partial regression is obtained.Conclusion. The primary squamous cell carcinoma is prone to an aggressive course and has an unfavorable prognosis, especially in patients over 60 years of age with skin and facial nerve damage, as well as the presence of regional and distant metastases. Differential diagnosis is necessary to exclude the secondary nature of the tumor. The presented case is a rare example of primary squamous cell carcinoma of the parotid salivary gland with extensive metastatic lesion and regression of the pathological process after polychemotherapy in combination with targeted therapy.

Prognostic significance of tumor microenvironment assessed by machine learning algorithm in surgically resected non-small cell lung cancer.

A methodology to assess the immune microenvironment (IME) of non-small cell lung cancer (NSCLC) has not been established, and the prognostic impact of IME factors is not yet clear. This study aimed to assess the IME factors and evaluate their prognostic values. We assessed CD8+ tumor-infiltrating lymphocyte (TIL) density, forkhead box protein P3+ (Foxp3+ ) TIL density, and programmed death receptor ligand-1 (PD-L1) tumor proportion score (TPS) using a machine-learning algorithm in whole-slide imaging (WSI). We dichotomized patients according to TIL density or TPS and compared their clinical outcomes. Between September 2014 and September 2015, 165 patients with NSCLC were enrolled in the study. We assessed IME factors in the epithelium, stroma, and their combination. An improvement in disease-free survival (DFS) was observed in the high CD8+ TIL density group in the epithelium, stroma, and the combination of both. Moreover, the group with high PD-L1 TPS in the epithelium showed better DFS than that with low PD-L1 TPS. In the multivariate analysis, the CD8+ TIL density in the combination of epithelium and stroma and PD-L1 TPS in the epithelium were independent prognostic factors (hazard ratio [HR] = 0.43; 95% confidence interval [CI] = 0.26-0.72; p = .001, HR = 0.49; 95% CI = 0.30-0.81; p = .005, respectively). Our approach demonstrated that the IME factors are related to survival in patients with NSCLC. The quantitative assessment of IME factors enables to discriminate patients with high risk of recurrence, who can be the candidates for adjuvant therapy. Assessing the CD8+ TIL density in the combination of epithelium and stroma might be more useful than their individual assessment because it is a simple and time-saving analysis of TILs in WSI.

A Crosstalk Between Castration-Resistant Prostate Cancer Cells, M2 Macrophages, and NK Cells: Role of the ATM-PI3K/AKT-PD-L1 Pathway

ABSTRACT Castration-resistant prostate cancer (CRPC) in males is associated with a poor prognosis and a higher risk of treatment-related adverse effects, with high mortality among cancers globally. It is thus imperative to explore novel potential molecules with dual therapeutic and biomarker functions. Based on the recent research findings, the expression levels of ataxia telangiectasia mutant kinase (ATM) in prostate cancer (PC) tissues collected from CRPC patients were higher than hormone-dependent PC patients. Using CRPC cell lines (C4–2 and CWR22Rv1), the transwell chamber experiments revealed ATM promoted macrophage recruitment in CRPC cells in vitro via C-X-C motif chemokine ligand 12 (CXCL12). Further in vitro investigations demonstrated that polarized macrophages prevented NK cell recruitment and reduced the immunocidal activity of NK cells against CRPC cell lines. Moreover, ATM boosted programmed death receptor ligand 1 (PD-L1) expression while inhibiting NK group 2D (NKG2D) ligand expression in selected cell lines via PI3K/AKT signaling pathway. The in vivo investigations revealed ATM induced proliferation of CRPC and macrophage recruitment, while the NK cell recruitment was found to suppress ATM expression and CRPC proliferation. In conclusion, it could be demonstrated that inhibiting ATM increased the susceptibility of CRPC to NK cell inhibitors by dampening the CXCL12 and PI3K/AKT-PD-L1 pathways, thereby offering a novel and individualized treatment protocol for treating CRPC.

MicroRNA-326 negatively regulates CD155 expression in lung adenocarcinoma.

Treatment with immune checkpoint inhibitors induces a durable response in some patients with non-small-cell lung cancer, but eventually gives rise to drug resistance. Upregulation of CD155 expression is implicated as one mechanism of resistance to programmed death receptor-1 (PD-1)/PD-1 ligand (PD-L1) inhibitors, and it is therefore important to characterize the mechanisms underlying regulation of CD155 expression in tumor cells. The aim of this study was to identify microRNAs (miRNAs) that might regulate CD155 expression at the posttranscriptional level in lung cancer. Comprehensive miRNA screening with target prediction programs and a dual-luciferase reporter assay identified miR-346, miR-328-3p, miR-326, and miR-330-5p as miRNAs that bind to the 3'-UTR of CD155 mRNA. Forced expression of these miRNAs suppressed CD155 expression in lung cancer cell lines. Immunohistochemical staining of CD155 in tissue specimens from 57 patients with lung adenocarcinoma revealed the median tumor proportion score for CD155 to be 68%. The abundance of miR-326 in these specimens with a low level of CD155 expression was significantly greater than in specimens with a high level (p < 0.005). Our results thus suggest that miR-326 negatively regulates CD155 expression in lung adenocarcinoma and might therefore play a role in the development of resistance to PD-1/PD-L1 inhibitors.

Effects of Tolerant Nanoparticles Loaded with Various Regulatory Molecules on the Development of Experimental Autoimmune Encephalomyelitis

This research investigated the effects of tolerating nanoparticles (tNPs) loaded with multiple regulatory molecules on progression of experimental autoimmune encephalomyelitis (EAE). The polylactic acid-glycolic acid copolymer (PLGA), multiple regulatory molecular fragments (Fc) (programmed death receptor ligand 1-Fc (PD-L1-Fc), CD47-Fc), transforming growth factor (TGF-β1), and multiple oligodendrocyte glycoprotein (MOG) antigen peptides (p-MOG) were selected to prepare the tNPs (MRM-tNPs) loaded with various regulatory molecules. Then, the MRM-tNPs were applied in MOG35-55 polypeptide-induced EAE mouse model. According to the treatment methods, the mice were rolled into a group A (BS therapeutic agent), a group B (no-load-NPs), a group C (MOG-tNPs), and a group D (MRM-tNPs). The therapeutic effects were evaluated by the inflammatory infiltration degree (IID), demyelination loss degree (DLD), and apoptosis rate (AR) of CD4+ and CD8+ T cells. The Results showed that the encapsulation rate (ER) of TGF-β1 was 87.65%, and its cumulative release rate (RR) was 58.22%. There were obvious fluorescence signals on MRM-tNPs, MRM-tNPs without PD-L1, and MRM-tNPs without CD47. The neurological function (NF) score in the group D after MRM-tNPs treatment was less than 2 points (P &lt;0.05). The scores of IID and DLD in the brain and spinal cord (SC) of EAE mice in the group D were much lower to those in groups A, B, and C, and the ARs of CD4+ and CD8+ T cells were higher (P &lt;0.05). In conclusion, the tNPs loaded with various regulatory molecules can promote the apoptosis of antigen-specific T cells (AST) and reduce the infiltration and demyelination of inflammatory cells, thus alleviating the EAE.

The Combination of PD-L1 and CTLA-4 Suppression Significantly Decreased the Expression Levels of Cancer Stem Cell Factors in the Pancreatic Cancer Cell Line

Background: It is thought that a limited number of aberrant cancer stem cells (CSCs), which encourage carcinogenesis, tumor metastasis, and treatment resistance, are the cause of pancreatic cancer, a disease with a high mortality rate. Increasing evidence shows that CSCs use immunosuppressive properties to avoid immune system identification. In Pancreatic cancer, the therapeutic consequences of the relationship between the expression of immune checkpoints such as programmed death receptor ligand-1 (PD-L1) and cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) and the presence of CSCs are poorly known. As a result, in the present investigation, we examined how the expression levels of CSCs were affected by PD-L1 and CTLA-4 knockdown using specific siRNA. Methods: Independently and together, PD-L1 and CTLA-4 siRNA were transfected into MIA PaCa-2 cells. RNA extraction and cDNA synthesis were then performed. Finally, using qRT-PCR, the gene expression levels of CSCs markers, including Nanog, CD133, CD44, and Oct-4, in transfected groups were measured. Results: In the MIA PaCa-2 cell line, siRNA-mediated inhibition of PD-L1 and CTLA-4 decreased the expression of CSC factors. Moreover, combined suppression of these two stemness-related immune checkpoints significantly decreased Nanog, CD133, CD44, and Oct-4 expression compared to inhibition of PD-L1 and CTLA-4 separately. Conclusion: Considering that the combination of PD-L1 and CTLA-4 suppression using siRNA significantly decreased the expression levels of CSCs factors, this approach may be regarded as an effective therapy for this cancer.

Real-World Biomarker Test Utilization and Subsequent Treatment in Patients with Early-Stage Non-small Cell Lung Cancer in the United States, 2011-2021.

Biomarker testing is increasingly crucial for patients with early-stage non-small cell lung cancer (eNSCLC). We explored biomarker test utilization and subsequent treatment in eNSCLC patients in the real-world setting. Using COTA's oncology database, this retrospective observational study included adult patients ≥ 18years old diagnosed with eNSCLC (disease stage 0-IIIA) between January 1, 2011 and December 31, 2021. Date of first eNSCLC diagnosis was the study index date. We reported testing rates by index year for patients who received any biomarker test within 6months of eNSCLC diagnosis and by each molecular marker. We also evaluated treatments received among patients receiving the five most common biomarker tests. Among the 1031 eNSCLC patients included in the analysis, 764 (74.1%) received ≥ 1 biomarker test within 6months of eNSCLC diagnosis. Overall, epidermal growth factor receptor (EGFR; 64%), anaplastic lymphoma kinase (ALK; 60%), programmed death receptor ligand 1 (PD-L1; 48%), ROS proto-oncogene 1 (ROS1; 46%), B-Raf proto-oncogene (40%), mesenchymal epithelial transition factor receptor (35%), Kirsten rat sarcoma viral oncogene (29%), RET proto-oncogene (22%), human epidermal growth factor receptor 2 (21%), and phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha (20%) were the 10 most frequently tested biomarkers. The proportion of patients undergoing biomarker testing rose from 55.3% in 2011 to 88.1% in 2021. The most common testing methods were Sanger sequencing for EGFR (244, 37%), FISH (fluorescence in situ hybridization) for ALK (464, 75%) and ROS1 (357, 76%), immunohistochemical assay for PD-L1 (450, 90%), and next-generation sequencing testing for other biomarkers. Almost all the 763 patients who received the five most common biomarker tests had a test before the initiation of a systemic treatment. This study suggests a high biomarker testing rate among patients with eNSCLC in the US, with testing rates for various biomarkers increasing over the past decade, indicating a continuous trend towards the personalization of treatment decisions.

Nano-Liposome Co-Loaded with C-X-C Chemokine Ligand 12/CXCR4 Pathway Inhibitor Synergistically Increases the Immune Efficacy of Anti-PD-L1 and Increase Anti-Tumor Activity of Effector T Cells

Blockade of the immune checkpoint programmed cell death receptor-1 (PD-1) or programmed death receptor ligand-1 (PD-L1) enhances the antitumor activity of effector T cells. However, many patients lack response to PD-1/PD-L1 therapy. Enhancing the efficacy of immune checkpoint inhibitors by improving the immunosuppressive tumor microenvironment (TME) has emerged as a promising cancer treatment strategy. In this study, a new nano-liposome (PD-L1/siCXCL12-Lp) of C-X-C chemokine ligand 12 (CXCL12) siRNA and anti-PD-L1 peptide (PD-L1/siCXCL12-Lp) responsive to matrix metalloproteinases (MMPs) was constructed, combined with siCXCL12. The regulation of TME and the immunomodulatory effect of anti-PD-L1 peptide to synergistically enhance the antitumor immune response. The animal experiment protocol was reviewed and approved by the Biomedical Ethics Committee of Peking University. This study showed that PD-L1/siCXCL12-Lp directly downregulated CXCL12 expression in vitro (33.8%) and in vivo (15.5%), and effectively increased the CD8+/Treg ratio (20.0%), which favored anti-PD-L1 peptides better exert its immune function. Combination therapy significantly inhibited tumor growth (52.08%) with good safety, exploring new ideas for cancer immunotherapy.

Efficacy and influencing factors of immunotherapy combined with chemotherapy and bevacizumab in patients with non-small cell lung cancer after epidermal growth factor receptor tyrosine kinase inhibitors treatment failure

Objective: To investigate the efficacy and influencing factors of immunotherapy combined with chemotherapy and bevacizumab in patients with non-small cell lung cancer (NSCLC) who failed epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) treatment. Methods: A retrospective analysis was made on the clinical data of 60 NSCLC patients who were treated with immunotherapy combined with chemotherapy and bevacizumab after EGFR-TKIs treatment failure in the Affiliated Cancer Hospital of Shandong First Medical University from January 2019 to March 2022. Patients were followed up by telephone or outpatient review up to October 1, 2022, with a median follow-up of 8.2 months (95%CI: 7.1-9.3). All 60 patients were followed up. The response evaluation criteria in solid tumors were used to evaluate the short-term efficacy. The adverse reactions of patients were evaluated according to the common terminology criteria for adverse events. The survival curve was drawn by Kaplan-Meier method. Cox proportional hazard regression models were utilized to analyze the influencing factors of progression-free survival (PFS). Results: Among the 60 NSCLC patients, 22 were males. The age ranged from 41 to 75 years, with a median age of 61 years. Eleven patients had partial response, 19 patients had stable disease and 30 patients had progressive disease. The median PFS was 8.2 months (95%CI: 7.2-9.2). The median PFS of patients with low expression of programmed death receptor-ligand 1 (PD-L1) [Tumor cell Proportion Score (TPS)<1%], moderate expression of PD-L1 (1%≤TPS≤49%), and high expression of PD-L1 (TPS≥50%) were 6.4 (95%CI: 4.8-8.0), 8.3 (95%CI: 7.3-9.3) and 10.6 months (95%CI: 7.2-14.1), respectively, and there were statistically significant differences (χ2=13.58, P<0.001). Multivariate Cox proportional risk regression model analysis showed that age>65 years old (HR=4.017, 95%CI: 1.468-10.992, P=0.007) was a risk factor for PFS in NSCLC patients who received immunotherapy combined with chemotherapy and bevacizumab after EGFR-TKIs treatment failure. Moderate expression of PD-L1 (HR=0.360, 95%CI: 0.139-0.930, P=0.035) and high expression of PD-L1 (HR=0.155, 95%CI: 0.039-0.625, P=0.009) were protective factors for PFS. Most of the treatment-related adverse reactions in the whole group were grade 1-2, including bone marrow suppression (n=24), nausea (n=25), decreased appetite (n=24), fatigue (n=22), vomiting (n=18), abnormal liver function (n=17), blood creatinine increased (n=10), and so on. These were tolerated by the patients. Conclusions: NSCLC patients who failed EGFR-TKIs treatment can tolerate adverse reactions related to immunotherapy combined with chemotherapy and bevacizumab treatment. PFS is significantly prolonged in those aged≤65 years and those with moderate and high expression of PD-L1.

Down-regulation of DNA key protein-FEN1 inhibits OSCC growth by affecting immunosuppressive phenotypes via IFN-γ/JAK/STAT-1

Oral squamous cell carcinoma (OSCC) escape from the immune system is mediated through several immunosuppressive phenotypes that are critical to the initiation and progression of tumors. As a hallmark of cancer, DNA damage repair is closely related to changes in the immunophenotypes of tumor cells. Although flap endonuclease-1 (FEN1), a pivotal DNA-related enzyme is involved in DNA base excision repair to maintain the stability of the cell genome, the correlation between FEN1 and tumor immunity has been unexplored. In the current study, by analyzing the clinicopathological characteristics of FEN1, we demonstrated that FEN1 overexpressed and that an inhibitory immune microenvironment was established in OSCC. In addition, we found that downregulating FEN1 inhibited the growth of OSCC tumors. In vitro studies provided evidence that FEN1 knockdown inhibited the biological behaviors of OSCC and caused DNA damage. Performing multiplex immunohistochemistry (mIHC), we directly observed that the acquisition of critical immunosuppressive phenotypes was correlated with the expression of FEN1. More importantly, FEN1 directly or indirectly regulated two typical immunosuppressive phenotype-related proteins human leukocyte antigen (HLA-DR) and programmed death receptor ligand 1 (PD-L1), through the interferon-gamma (IFN-γ)/janus kinase (JAK)/signal transducer and activator transcription 1 (STAT1) pathway. Our study highlights a new perspective on FEN1 action for the first time, providing theoretical evidence that it may be a potential immunotherapy target for OSCC.

Peptide functionalized nanocarriers for targeted drug delivery in cancer therapy.

The intrinsic limitations of conventional cancer therapies have prompted the development of nanocarriers for more effective and safer cancer treatment. Amongst these, nanocarriers functionalized with tumor-targeting moieties have been utilized to enhance delivery of cancer therapeutics. However, recent reports have revealed that only a modest increase in tumor targeting is typically achieved with this approach. Poor tumor accumulation is largely due to formation of a serum protein corona on the surface of the nanocarriers in circulation, which hinders targeting and leads to nonspecific tissue distribution, immune recognition and rapid blood clearance. Here, we present three highly efficient tumor-targeting nanocarriers that overcome the aforementioned issues. These nanocarriers are functionalized with the acidity-triggered rational membrane (ATRAM) peptide that facilitates internalization specifically into cancer cells within the acidic tumor microenvironment. The first system is a hybrid nanocarrier that consists of a drug-loaded polylactic-co-glycolic acid (PLGA) core covalently ‘wrapped’ with a crosslinked bovine serum albumin (BSA) shell. Second are upconversion mesoporous silica nanospheres (UMSNs), with combined photodynamic therapy, photothermal therapy and imaging capabilities, that consist of a lanthanide-doped core ‘wrapped’ with lipid-polyethylene glycol (DSPE-PEG-maleimide). The final system consists of drug-loaded mesoporous silica nanoparticles (MSNs) coated with a lipid bilayer composed of DPPC/Chol/DSPE-PEG-mal. The lipid coat is then functionalized with programmed death receptor ligand-1 antibody (anti-PD-L1 antibody, atezolizumab) to disrupt the programmed death 1 (PD-1) interaction that inhibits the anticancer activity of tumor-infiltrating immune cells. In all three systems, the BSA or lipid coats serve to minimize interactions with serum proteins, which allows the nanocarriers to evade immune recognition and extends the in vivo circulation half-life. All three systems exhibit remarkable tumor-targeting efficiency leading to highly potent anticancer activity, while exhibiting negligible toxicity to healthy tissue. Thus, all three systems represent highly promising nanoplatforms for the targeted delivery of cancer therapeutics.

Expression of neuroendocrine markers predicts increased survival in triple-negative breast cancer patients.

The significance of neuroendocrine (NE) markers in triple-negative breast cancer (TNBC) patients has not been investigated. This study aims to clarify the incidence and prognostic significance of NE marker expression in TNBC, determine its association with other clinicopathological parameters, and further explore the pathological features and potential treatment options for TNBC patients expressing NE markers. Clinicopathological data were collected from 396 TNBC patients undergoing radical breast cancer surgery at Peking Union Medical College Hospital from January 2002 to December 2014, with a final follow-up in July 2019. Immunohistochemistry (IHC) staining was performed for NE markers including chromogranin A (CgA) and synaptophysin (Syn). For TNBC patients with positive NE marker expression, IHC staining was then performed for alpha-thalassemia/mental retardation X-linked (ATRX), O(6)-methylguanine-methyltransferase (MGMT), somatostatin receptor 2 (SSTR2), and programmed death receptor-ligand 1 (PD-L1). The chi-square or Fisher exact test was used to evaluate the correlations between NE marker expression and other parameters. Survival curves were plotted using the Kaplan-Meier (K-M) method to assess the prognostic significance of NE markers in TNBC. NE marker-positive staining was observed in 7.6% (30/396) of all TNBC cases. Only 0.5% (2/396) cases had ≥ 90% neoplastic cells expressing NE markers. Positive NE marker expression was associated with negative basal-like marker expression. K-M survival analysis showed that the NE marker-positive TNBC patients had higher disease-free survival (DFS) rates than the NE marker-negative patients at the same stage. Among the 30 NE marker-positive TNBC cases, 13.3% and 26.7% showed negative IHC staining for ATRX and MGMT, respectively, while 13.3% had a 3+ score for SSTR2 IHC staining. For PD-L1 IHC staining, 13.3% of the 30 TNBC cases were higher than 10 scores in Combined Positive Score (CPS), and 10.0% were higher than 10% in Tumor Cell Proportion Score (TPS). There was a small proportion of TNBC patients expressing NE markers. TNBC patients with positive NE marker expression had a better prognosis than the negative group at the same stage. TNBC cases with positive NE marker expression may potentially benefit from immunotherapy or somatostatin analogue treatment.

Mechanisms and Strategies to Overcome PD-1/PD-L1 Blockade Resistance in Triple-Negative Breast Cancer.

Triple-negative breast cancer (TNBC) is characterized by a high rate of systemic metastasis, insensitivity to conventional treatment and susceptibility to drug resistance, resulting in a poor patient prognosis. The immune checkpoint inhibitors (ICIs) represented by antibodies of programmed death receptor 1 (PD-1) and programmed death receptor ligand 1 (PD-L1) have provided new therapeutic options for TNBC. However, the efficacy of PD-1/PD-L1 blockade monotherapy is suboptimal immune response, which may be caused by reduced antigen presentation, immunosuppressive tumor microenvironment, interplay with other immune checkpoints and aberrant activation of oncological signaling in tumor cells. Therefore, to improve the sensitivity of TNBC to ICIs, suitable patients are selected based on reliable predictive markers and treated with a combination of ICIs with other therapies such as chemotherapy, radiotherapy, targeted therapy, oncologic virus and neoantigen-based therapies. This review discusses the current mechanisms underlying the resistance of TNBC to PD-1/PD-L1 inhibitors, the potential biomarkers for predicting the efficacy of anti-PD-1/PD-L1 immunotherapy and recent advances in the combination therapies to increase response rates, the depth of remission and the durability of the benefit of TNBC to ICIs.

Expression of nucleus accumbens-1 in colon cancer negatively modulates antitumor immunity.

Nucleus accumbens-1 (NAC-1) is highly expressed in a variety of tumors, including colon cancer, and is closely associated with tumor recurrence, metastasis, and invasion. To determine whether and how NAC-1 affects antitumor immunity in colon cancer. NAC-1-siRNA was transfected into RKO colon cancer cells to knock down NAC expression; tumor cells with or without knockdown of NAC-1 were treated with CD8+ T cells to test their cytocidal effect. The level of the immune checkpoint programmed death receptor-1 ligand (PD-L1) in colon cancer cells with or without knockdown of NAC-1 was analyzed using Quantitative real-time polymerase chain reaction and Western blotting. A double luciferase reporter assay was used to examine the effects of NAC-1 on the transcription of PD-L1. Mice bearing MC-38-OVA colon cancer cells expressing NAC-shRNA or control-shRNA were treated with OT-I mouse CD8+ T cells to determine the tumor response to immunotherapy. Immune cells in the tumor tissues were analyzed using flow cytometry. NAC-1, PD-L1 and CD8+ T cells in colon cancer specimens from patients were examined using immunohistochemistry staining. Knockdown of NAC-1 expression in colon cancer cells significantly enhanced the cytocidal effect of CD8+ T cells in cell culture experiments. The sensitizing effect of NAC-1 knockdown on the antitumor action of cytotoxic CD8+ T cells was recapitulated in a colon cancer xenograft animal model. Furthermore, knockdown of NAC-1 in colon cancer cells decreased the expression of PD-L1 at both the mRNA and protein levels, and this effect could be rescued by transfection of an RNAi-resistant NAC-1 expression plasmid. In a reporter gene assay, transient expression of NAC-1 in colon cancer cells increased the promoter activity of PD-L1, indicating that NAC-1 regulates PD-L1 expression at the transcriptional level. In addition, depletion of tumoral NAC-1 increased the number of CD8+ T cells but decreased the number of suppressive myeloid-derived suppressor cells and regulatory T cells. Tumor expression of NAC-1 is a negative determinant of immunotherapy.