Pivotal role of long non-coding ribonucleic acid-X-inactive specific transcript in regulating immune checkpoint programmed death ligand 1 through a shared pathway between miR-194-5p and miR-155-5p in hepatocellular carcinoma

BACKGROUND Anti-programmed death therapy has thrust immunotherapy into the spotlight.However,such therapy has a modest response in hepatocellular carcinoma(HCC).Epigenetic immunomodulation is a suggestive combinatorial therapy with immune checkpoint blockade.Non-coding ribonucleic acid(ncRNA)driven regulation is a major mechanism of epigenetic modulation.Given the wide range of ncRNAs that co-opt in programmed cell-death protein 1(PD-1)/programmed death ligand 1(PD-L1)regulation,and based on the literature,we hypothesized that miR-155-5p,miR-194-5p and long non-coding RNAs(lncRNAs)X-inactive specific transcript(XIST)and MALAT-1 are involved in a regulatory upstream pathway for PD-1/PD-L1.Recently,nutraceutical therapeutics in cancers have received increasing attention.Thus,it is interesting to study the impact of oleuropein on the respective study key players.AIM To explore potential upstream regulatory ncRNAs for the immune checkpoint PD-1/PD-L1.METHODS Bioinformatics tools including microrna.org and lnCeDB software were adopted to detect targeting of miR-155-5p,miR-194-5p and lncRNAs XIST and MALAT-1 to PD-L1 mRNA,respectively.In addition,Diana tool was used to predict targeting of both aforementioned miRNAs to lncRNAs XIST and MALAT-1.HCC and normal tissue samples were collected for scanning of PD-L1,XIST and MALAT-1 expression.To study the interaction among miR-155-5p,miR-194-5p,lncRNAs XIST and MALAT-1,as well as PD-L1 mRNA,a series of transfections of the Huh-7 cell line was carried out.RESULTS Bioinformatics software predicted that miR-155-5p and miR-194-5p can target PDL1,MALAT-1 and XIST.MALAT-1 and XIST were predicted to target PD-L1 mRNA.PD-L1 and XIST were significantly upregulated in 23 HCC biopsies compared to healthy controls;however,MALAT-1 was barely detected.MiR-194 induced expression elevated the expression of PD-L1,XIST and MALAT-1.However,overexpression of miR-155-5p induced the upregulation of PD-L1 and XIST,while it had a negative impact on MALAT-1 expression.Knockdown of XIST did have an impact on PD-L1 expression;however,following knockdown of the negative regulator of X-inactive specific transcript(TSIX),PD-L1 expression was elevated,and abolished MALAT-1 activity.Upon co-transfection of miR-194-5p with siMALAT-1,PD-L1 expression was elevated.Co-transfection of miR-194-5p with siXIST did not have an impact on PD-L1 expression.Upon co-transfection of miR-194 with siTSIX,PD-L1 expression was upregulated.Interestingly,the same PD-L1 expression pattern was observed following miR-155-5p cotransfections.Oleuropein treatment of Huh-7 cells reduced the expression profile of PD-L1,XIST,and miR-155-5p,upregulated the expression of miR-194-5p and had no significant impact on the MALAT-1 expression profile.CONCLUSION This study reported a novel finding revealing that opposing acting miRNAs in HCC,have the same impact on PD-1/PD-L1 immune checkpoint by sharing a common signaling pathway.

Pathological significance of abnormal recepteur d'origine nantais and programmed death ligand 1 expression in colorectal cancer

BACKGROUND Programmed death ligand 1(PD-L1) immunotherapy remains poorly efficacious in colorectal cancer(CRC). The recepteur d'origine nantais(RON) receptor tyrosine kinase plays an important role in regulating tumor immunity.AIM To identify the patterns of RON and PD-L1 expression and explore their clinical significance in CRC.METHODS Gene expression data from the Gene Expression Omnibus database(GEO;n = 290) and patients at the First Affiliated Hospital, Zhejiang University School of Medicine(FAHZUSM;n = 381) were analyzed to determine the prognostic value of RON and PD-L1 expression within the tumor microenvironment of CRC. HT29 cell line was treated with BMS-777607 to explore the relationship between RON activity and PD-L1 expression. Signaling pathways and protein expression perturbed by RON inhibition were evaluated by cellular immunofluorescence and Western blot.RESULTS In the GEO patient cohort, cut-off values for RON and PD-L1 expression were determined to be 7.70 and 4.3, respectively. Stratification of patients based on these cutoffs demonstrated that high expression of RON and PD-L1 was associated with a poor prognosis. In the FAHZUSM cohort, rates of high expression of RON in tumor cells, high PD-L1 expression in tumor cells and tumor infiltrating monocytes, and both high RON and high PD-L1 expression in the tumor microenvironment were 121(32%), 43(11%), 91(24%), and 51(13.4%), respectively. High expression of RON was significantly correlated with high expression of PD-L1 in the tumor cell compartment(P < 0.001). High expression of RON and that of PD-L1 were independent prognostic factors for poorer overall survival. Concurrent high expression of both RON and PD-L1 in the tumor microenvironment was significantly associated with a poor prognosis. In vitro, BMS-777607 inhibited the phosphorylation of RON, inhibited PD-L1 expression, and attenuated activation of the ERK1/2 and AKT signaling pathways in CRC cells.CONCLUSION RON, PD-L1, and their crosstalk are significant in predicting the prognostic value of CRC. Moreover, phosphorylation of RON upregulates PD-L1 expression, which provides a novel approach to immunotherapy in CRC.

Immunotherapy against programmed death-1/programmed death ligand 1 in hepatocellular carcinoma: Importance of molecular variations, cellular heterogeneity, and cancer stem cells

Hepatocellular carcinoma(HCC)is a heterogeneous malignancy related to diverse etiological factors.Different oncogenic mechanisms and genetic variations lead to multiple HCC molecular classifications.Recently,an immune-based strategy using immune checkpoint inhibitors(ICIs)was presented in HCC therapy,especially with ICIs against the programmed death-1(PD-1)and its ligand PD-L1.However,despite the success of anti-PD-1/PD-L1 in other cancers,a substantial proportion of HCC patients fail to respond.In this review,we gather current information on biomarkers of anti-PD-1/PD-L1 treatment and the contribution of HCC heterogeneity and hepatic cancer stem cells(CSCs).Genetic variations of PD-1 and PD-L1 are associated with chronic liver disease and progression to cancer.PD-L1 expression in tumoral tissues is differentially expressed in CSCs,particularly in those with a close association with the tumor microenvironment.This information will be beneficial for the selection of patients and the management of the ICIs against PD-1/PD-L1.

Comprehensive insights into the effects and regulatory mechanisms of immune cells expressing programmed death-1/programmed death ligand 1 in solid tumors

The programmed cell death-1(PD-1)/programmed cell death ligand 1(PD-L1)signaling pathway is an important mechanism in tumor immune escape,and expression of PD-L1 on tumor cells has been reported more frequently.However,accumulating evidence suggests that PD-1/PD-L1 is also widely expressed on immune cells,and that regulation is also critical for tumor immune responses.In this review,we emphasized that under solid tumor conditions,the immunoregulatory effects of immune cells expressing PD-1 or PD-L1,affected the prognoses of cancer patients.Therefore,a better understanding of the mechanisms that regulate PD-1 or PD-L1 expression on immune cells would provide clear insights into the increased efficacy of anti-PD antibodies and the development of novel tumor immunotherapy strategies.

Assessment of programmed death-ligand 1 expression in primary tumors and paired lymph node metastases of gastric adenocarcinoma

BACKGROUND Anti-programmed death-1/programmed death-ligand 1(PD-1/PD-L1)immuno-therapy has demonstrated promising results on gastric cancer(GC).However,PD-L1 can express differently between metastatic sites and primary tumors(PT).AIM To compare PD-L1 status in PT and matched lymph node metastases(LNM)of GC patients and to determine the correlation between the PD-L1 status and clinicopathological characteristics.METHODS We retrospectively reviewed 284 GC patients who underwent D2-gastrectomy.PD-L1 was evaluated by immunohistochemistry(clone SP142)using the com-bined positive score.All PD-L1+PT staged as pN+were also tested for PD-L1 expression in their LNM.PD-L1(-)GC with pN+served as the comparison group.RESULTS Among 284 GC patients included,45 had PD-L1+PT and 24 of them had pN+.For comparison,44 PD-L1(-)cases with pN+were included(sample loss of 4 cases).Of the PD-L1+PT,54.2%(13/24 cases)were also PD-L1+in the LNM.Regarding PD-L1(-)PT,9.1%(4/44)had PD-L1+in the LNM.The agreement between PT and LNM had a kappa value of 0.483.Larger tumor size and moderate/severe peritumoral inflammatory response were associated with PD-L1 positivity in both sites.There was no statistical difference in overall survival for PT and LNM according to the PD-L1 status(P=0.166 and P=0.837,respectively).CONCLUSION Intra-patient heterogeneity in PD-L1 expression was observed between the PT and matched LNM.This disagreement in PD-L1 status may emphasize the importance of considering different tumor sites for analyses to select patients for immunotherapy.

Efficacy of chemotherapy containing bevacizumab in patients with metastatic colorectal cancer according to programmed cell death ligand 1

BACKGROUND Bevacizumab,an anti-vascular endothelial growth factor(VEGF)monoclonal antibody,inhibits angiogenesis and reduces tumor growth.Serum VEGF-C,lactate dehydrogenase,and inflammatory markers have been reported as predictive markers related to bevacizumab treatment.Programmed cell death ligand 1(PD-L1)could act upon VEGF receptor 2 to induce cancer cell angiogenesis and metastasis.AIM To investigate the efficacy of bevacizumab-containing chemotherapy in patients with metastatic colorectal cancer(CRC)according to the expression of PD-L1.METHODS This analysis included CRC patients who received bevacizumab plus FOLFOX or FOLFIRI as first-line therapy between June 24,2014 and February 28,2022,at Samsung Medical Center(Seoul,South Korea).Analysis of patient data included evaluation of PD-L1 expression by the combined positive score(CPS).We analyzed the efficacy of bevacizumab according to PD-L1 expression status in patients with CRC.RESULTS A total of 124 patients was included in this analysis.Almost all patients were treated with bevacizumab plus FOLFIRI or FOLFOX as the first-line chemotherapy.While 77%of patients received FOLFOX,23%received FOLFIRI as backbone first-line chemotherapy.The numbers of patients with a PD-L1 CPS of 1 or more,5 or more,or 10 or more were 105(85%),64(52%),and 32(26%),respectively.The results showed no significant difference in progression-free survival(PFS)and overall survival(OS)with bevacizumab treatment between patients with PDL1 CPS less than 1 and those with PD-L1 CPS of 1 or more(PD-L1<1%vs PD-L1≥1%;PFS:P=0.93,OS:P=0.33),between patients with PD-L1 CPS less than 5 and of 5 or more(PD-L1<5%vs PD-L1≥5%;PFS:P=0.409,OS:P=0.746),and between patients with PD-L1 CPS less than 10 and of 10 or more(PD-L1<10%vs PD-L1≥10%;PFS:P=0.529,OS:P=0.568).CONCLUSION Chemotherapy containing bevacizumab can be considered as first-line therapy in metastatic CRC irrespective of PD-L1 expression.

Programmed death 1, ligand 1 and 2 correlated genes and their association with mutation, immune infiltration and clinical outcomes of hepatocellular carcinoma

BACKGROUND The exact regulation network of programmed death 1(PD-1), programmed death ligand 1(PD-L1), and programmed death ligand 2(PD-L2) signaling in immune escape is largely unknown. We aimed to describe the gene expression profiles related to PD-1 as well as its ligands PD-L1 and PD-L2, thus deciphering their possible biological processes in hepatocellular carcinoma(HCC).AIM To find the possible mechanism of function of PD-1, PD-L1, and PD-L2 in HCC.METHODS Based on the expression data of HCC from The Cancer Genome Atlas, the PD-1/PD-L1/PD-L2 related genes were screened by weighted correlation network analysis method and the biological processes of certain genes were enriched. Relation of PD1/PD-L1/PD-L2 with immune infiltration and checkpoints was investigated by co-expression analysis. The roles of PD-1/PD-L1/PD-L2 in determination of clinical outcome were also analyzed.RESULTS Mutations of calcium voltage-gated channel subunit alpha1 E, catenin beta 1, ryanodine receptor 2, tumor suppressor protein p53, and Titin altered PD-1/PDL1/PD-L2 expression profiles in HCC. PD-1, PD-L1, and PD-L2 related genes were mainly enriched in biological procedures of T cell activation, cell adhesion, and other important lymphocyte effects. In addition, PD-1/PD-L1/PD-L2 was related with immune infiltration of CD8 T cells, cytotoxic lymphocytes,fibroblasts, and myeloid dendritic cells. Immune checkpoints of CTLA4, CD27, CD80, CD86, and CD28 were significantly related to the PD-1/PD-L1/PD-L2 axis. Clinically, PD-1 and PD-L2 expression was correlated with recurrence(P = 0.005 for both), but there was no significant correlation between their expression and HCC patient survival.CONCLUSION Mutations of key genes influence PD-1, PD-L1, and PD-L2 expression. PD-1, PDL1, and PD-L2 related genes participate in T cell activation, cell adhesion, and other important lymphocyte effects. The finding that PD-1/PD-L1/PD-L2 is related to immune infiltration and other immune checkpoints would expand our understanding of promising anti-PD-1 immunotherapy.

The prognostic value of programmed cell death ligand 1expression in non-Hodgkin lymphoma:a meta-analysis

Objective: Although the prognostic value of programmed cell death-ligand 1(PD-L1) expression in non-Hodgkin lymphoma(NHL) has been evaluated in many studies, the results remain controversial. To investigate the prognostic role of PD-L1 expression and the association between PD-L1 expression and clinicopathological features of NHL, we performed a meta-analysis.Methods: The Pub Med, EMBASE, and Cochrane Library databases were searched up to November 30, 2017. The hazard ratio(HR), 95% confidence interval(CI), and odds ratios(OR) with 95% CIs were combined to evaluate the association of PD-L1 expression with overall survival(OS) and clinicopathological features. Review manager 5.3 and STATA 12.0 were used in this meta-analysis.Results: A total of 2,005 patients across nine studies were enrolled in our meta-analysis, and the pooled results showed that high PD-L1 expression was associated with a poor prognosis(HR=2.04, 95% CI: 1.18–3.54, P=0.01). In the subgroup analysis according to histology types, pooled results demonstrated that an increased PD-L1 expression was an unfavorable prognostic factor for diffuse large B-cell lymphoma(HR=1.92, 95% CI: 1.06–3.48, P=0.03) but not for natural killer/T-cell lymphoma(HR=2.41, 95%CI: 0.47–12.22, P=0.29). Pooled ORs indicated that PD-L1 expression was higher in NHL with international prognostic indices of≥3. However, PD-L1 expression had no correlation with gender, age, disease stage, lactate dehydrogenase level, B symptoms, and germinal center B-cell-like lymphoma.Conclusions: High PD-L1 expression was a poor prognostic biomarker in patients with NHL. Because of our limited sample size,high-quality studies with larger sample sizes are needed to validate our results.

Anti-programmed cell death ligand 1-based immunotherapy in recurrent hepatocellular carcinoma with inferior vena cava tumor thrombus and metastasis:Three case reports

BACKGROUND Recurrent hepatocellular carcinoma(HCC)with inferior vena cava tumor thrombus is a great challenge for oncologists and has a poor prognosis.To date,the safety and efficacy of programmed cell death ligand 1(PD-L1)inhibitors are still unknown.CASE SUMMARY A 59-year-old male was identified as having a tumor thrombus in the inferior vena cava 3 years after surgery.The patient underwent a second surgery and adjuvant chemotherapy.However,the level of alpha-fetoprotein was elevated after 2 mo,and lung metastases and mediastinal lymph node metastases were identified.The expression of PD-L1 in HCC and inferior vena cava tumor thrombus tissues was analyzed by immunohistochemistry.Then,the patient received atezolizumab immunotherapy.The level of alpha-fetoprotein dropped to normal,the mediastinal lymph node metastases decreased in size and the lung metastases disappeared after 3 mo of immunotherapy.The patient had no signs of recurrence at 21 mo of follow-up.A 60-year-old male underwent left hepatic tumor resection,inferior vena cava incision and thrombus removal,followed by regular chemotherapy.The patient developed lung and splenic metastases after surgery.Pembrolizumab was used for six courses,and the splenic metastasis shrank,after which splenectomy was performed.The patient continued to receive pembrolizumab for thirteen courses,and the lung metastases showed no progression.A 34-year-old male was diagnosed with liver cancer with inferior vena cava tumor thrombus.The patient underwent right hepatectomy and received tislelizumab for three courses.He is still receiving immunotherapy and in good condition.CONCLUSION Anti-PD-L1 therapy in HCC patients with inferior vena cava tumor thrombus and metastasis is associated with relatively good patient outcomes.

Research progress regarding programmed cell death 1/programmed cell death ligand 1 inhibitors combined with targeted therapy for treating hepatocellular carcinoma

In recent years,a number of targeted therapeutic agents have achieved success in phase III trials in patients with advanced hepatocellular carcinoma(HCC),including sorafenib,lenvatinib,and regorafenib.Immunotherapy is considered to be an effective treatment for advanced HCC.Immune checkpoint inhibitors targeting programmed cell death 1(PD-1)/programmed cell death ligand 1(PDL1)are important antitumor immunotherapy agents that represent breakthroughs in the treatment of advanced HCC.However,treating advanced HCC is still a great challenge,and the need for new treatments remains urgent.This review briefly summarizes the research progress in the use of PD-1/PD-L1 inhibitors combined with targeted therapy for treating HCC.

Risk of interstitial lung disease with the use of programmed cell death 1 (PD-1) inhibitor compared with programmed cell death ligand 1 (PD-L1) inhibitor in patients with breast cancer: A systematic review and meta-analysis

Background:Programmed cell death 1(PD-1)and programmed cell death ligand 1(PD-L1)inhibitors have become integral elements within the current landscape of breast cancer treatment modalities;however,they are associ-ated with interstitial lung disease(ILD),which is rare but potentially fatal.Notably,only a few studies have compared the difference in ILD incidence between PD-1 and PD-L1 inhibitors.Therefore,this study aimed to assess the discrepancies regarding ILD risk between the two immune checkpoint inhibitors.We also reported three cases of ILD after PD-1 inhibitor treatment.Methods:We comprehensively searched PubMed,EMBASE,and the Cochrane Library to identify clinical trials that investigated PD-1/PD-L1 inhibitor treatment for patients with breast cancer.Pooled overall estimates of incidence and risk ratio(RR)were calculated with a 95%confidence interval(CI),and a mirror group analysis was per-formed using eligible studies.Results:This meta-analysis included 29 studies with 4639 patients who received PD-1/PD-L1 inhibitor treatment.A higher ILD incidence was observed among 2508 patients treated with PD-1 inhibitors than among 2131 patients treated with PD-L1 inhibitors(0.05 vs.0.02).The mirror group analysis further revealed a higher ILD event risk in patients treated with PD-1 inhibitors than in those treated with PD-L1 inhibitors(RR=2.34,95%CI,1.13-4.82,P=0.02).Conclusion:Our findings suggest a greater risk of ILD with PD-1 inhibitors than with PD-L1 inhibitors.These findings are instrumental for clinicians in treatment deliberations,and the adoption of more structured diagnostic approaches and management protocols is necessary to mitigate the risk of ILD.

PD-1/PD-L1 Signaling Pathway and Tumor Immune Escape

PD-1 and its ligands PD-L1 and PD-L2 are widely expressed on the surface of a variety of cells and are a group of costimulatory molecules related to negative immune regulation. The activation of the PD-1/PD-L1 signaling pathway is beneficial for tumors to escape from immune surveillance, but the specific tumor immune escape mechanism is not yet clear. As far as the efficacy of anti-PD-1 and anti-PD-L1 antibodies is concerned, more in-depth research on tumor immune escape mechanisms is still needed. The article summarizes these findings to provide ideas for antitumor immunotherapy.

Interferon-gamma and tumor necrosis factor-alpha synergistically enhance the immunosuppressive capacity of human umbilical-cordderived mesenchymal stem cells by increasing PD-L1 expression

BACKGROUND The immunosuppressive capacity of mesenchymal stem cells(MSCs)is dependent on the“license”of several proinflammatory factors to express immunosuppressive factors such as programmed cell death 1 ligand 1(PD-L1),which determines the clinical therapeutic efficacy of MSCs for inflammatory or immune diseases.In MSCs,interferon-gamma(IFN-γ)is a key inducer of PD-L1 expression,which is synergistically enhanced by tumor necrosis factor-alpha(TNF-α);however,the underlying mechanism is unclear.AIM To reveal the mechanism of pretreated MSCs express high PD-L1 and explore the application of pretreated MSCs in ulcerative colitis.METHODS We assessed PD-L1 expression in human umbilical-cord-derived MSCs(hUC-MSCs)induced by IFN-γand TNF-α,alone or in combination.Additionally,we performed signal pathway inhibitor experiments as well as RNA interference experiments to elucidate the molecular mechanism by which IFN-γalone or in combination with TNF-αinduces PD-L1 expression.Moreover,we used luciferase reporter gene experiments to verify the binding sites of the transcription factors of each signal transduction pathway to the targeted gene promoters.Finally,we evaluated the immunosuppressive capacity of hUC-MSCs treated with IFN-γand TNF-αin both an in vitro mixed lymphocyte culture assay,and in vivo in mice with dextran sulfate sodium-induced acute colitis.RESULTS Our results suggest that IFN-γinduction alone upregulates PD-L1 expression in hUC-MSCs while TNF-αalone does not,and that the co-induction of IFN-γand TNF-αpromotes higher expression of PD-L1.IFN-γinduces hUCMSCs to express PD-L1,in which IFN-γactivates the JAK/STAT1 signaling pathway,up-regulates the expression of the interferon regulatory factor 1(IRF1)transcription factor,promotes the binding of IRF1 and the PD-L1 gene promoter,and finally promotes PD-L1 mRNA.Although TNF-αalone did not induce PD-L1 expression in hUCMSCs,the addition of TNF-αsignificantly enhanced IFN-γ-induced JAK/STAT1/IRF1 activation.TNF-αupregulated IFN-γreceptor expression through activation of the nuclear factor kappa-B signaling pathway,which significantly enhanced IFN-γsignaling.Finally,co-induced hUC-MSCs have a stronger inhibitory effect on lymphocyte proliferation,and significantly ameliorate weight loss,mucosal damage,inflammatory cell infiltration,and up-regulation of inflammatory factors in colitis mice.CONCLUSION Overall,our results suggest that IFN-γand TNF-αenhance both the immunosuppressive ability of hUC-MSCs and their efficacy in ulcerative colitis by synergistically inducing high expression of PD-L1.

Hepatic arterial infusion chemotherapy with anti-angiogenesis agents and immune checkpoint inhibitors for unresectable hepatocellular carcinoma and meta-analysis

BACKGROUND Hepatic arterial infusion chemotherapy(HAIC)has been proven to be an ideal choice for treating unresectable hepatocellular carcinoma(uHCC).HAIC-based treatment showed great potential for treating uHCC.However,large-scale studies on HAIC-based treatments and meta-analyses of first-line treatments for uHCC are lacking.AIM To investigate better first-line treatment options for uHCC and to assess the safety and efficacy of HAIC combined with angiogenesis inhibitors,programmed cell death of protein 1(PD-1)and its ligand(PD-L1)blockers(triple therapy)under real-world conditions.METHODS Several electronic databases were searched to identify eligible randomized controlled trials for this meta-analysis.Study-level pooled analyses of hazard ratios(HRs)and odds ratios(ORs)were performed.This was a retrospective single-center study involving 442 patients with uHCC who received triple therapy or angiogenesis inhibitors plus PD-1/PD-L1 blockades(AIPB)at Sun Yat-sen University Cancer Center from January 2018 to April 2023.Propensity score matching(PSM)was performed to balance the bias between the groups.The Kaplan-Meier method and cox regression were used to analyse the survival data,and the log-rank test was used to compare the suvival time between the groups.RESULTS A total of 13 randomized controlled trials were included.HAIC alone and in combination with sorafenib were found to be effective treatments(P values for ORs:HAIC,0.95;for HRs:HAIC+sorafenib,0.04).After PSM,176 HCC patients were included in the analysis.The triple therapy group(n=88)had a longer median overall survival than the AIPB group(n=88)(31.6 months vs 14.6 months,P<0.001)and a greater incidence of adverse events(94.3%vs 75.4%,P<0.001).CONCLUSION This meta-analysis suggests that HAIC-based treatments are likely to be the best choice for uHCC.Our findings confirm that triple therapy is more effective for uHCC patients than AIPB.

Immunotherapy for metastatic gastric cancer

This editorial discusses the article written by Chen et al that was published in the latest edition of the World Journal of Gastrointestinal Surgery.The current study found that programmed cell death 1 ligand 1(PD-L1)expression is considered as one of the pan-cancer biomarkers of immune checkpoint inhibitors(ICIs)treatment response.Four molecular subtypes are widely used to guide and evaluate the prognosis and diagnosis and treatment of gastric cancer(GC)patients.Clinical trials of ICI treatment including Nivolumab,Pembrolizumab,Avelumab have been conducted for metastatic GC(mGC).The effects of various single agent ICIs on mGC therapy varied.ICIs combined with chemotherapy can indeed bring survival benefits to patients with mGC.Combining ICIs with chemotherapy can give more patients the chance of surgery in the treatment of GC transformation.However,not all PD-L1 positive patients can benefit from it.It is urgent to find better biomarkers to predict the response of ICIs for more precise clinical treatment.

The clinicopathological and prognostic significance of PD-L1 expression in pancreatic cancer:A meta-analysis

Background: Immunotherapy has shown promise against solid tumors. However, the clinical significance of programmed cell death 1(PD-1) and programmed cell death ligand 1(PD-L1) in pancreatic ductal adenocarcinoma(PDAC) remains unclear. This meta-analysis aimed to analyze the prognostic effect of PD-L1 in PDAC.Data sources: Electronic search of the Pub Med, Cochrane Library and Web of Science was performed until December 2016. Through database searches, we identified articles describing the relationship between PD-L1 status and PDAC patient prognosis. Meta-analysis was performed to investigate the relationship between PD-1 and overall survival(OS).Results: Nine studies with 989 PDAC patients were included for PD-L1 expression analysis. And 5 studies with 688 PDAC patients were included in the prognostic analysis. The PD-L1 positive rate measured by immunohistochemistry(IHC) was higher than that measured by polymerase chain reaction(PCR)(P < 0.001). PDAC patients with high expression levels of PD-L1 had significantly reduced OS(HR = 2.34;95% CI: 1.78–3.08). Subgroup analysis showed that the prognostic effect of PD-L1 levels was similar between the IHC and PCR methods. The PD-L1 positive rate was associated with PDAC T stages; the PD-L1 positive rate in the T3–4 group was higher than that in the T1-2 group(OR = 0.37; P = 0.001).Conclusions: High PD-L1 expression levels predicted a poor prognosis in PDAC patients. Thus, PD-L1 status helps determine treatment in PDAC patients.

Expression of programmed death 1 and its ligands in the liver of autoimmune hepatitis C57BL/6 mice

Background Autoimmune hepatitis （AIH） is a chronic inflammatory liver disease with unknown etiology. Programmed death 1 （PD-1） and its ligands （PD-L1 and PD-L2）, BT-H1/PD-L1 and B7-DC/PD-L2, are new CD28-B7 family members that are involved in the regulation of immune responses. Previous observation suggests that PD-1 system plays an inhibitory role in regulating peripheral blood T cells, B cells and myeloid cells, thus their abnormality may be related to autoimmune diseases. This study aimed to explore the role of PD-1/PD-L1, L2 system in the pathogenesis of AIH. Methods The mice model of experimental autoimmune hepatitis （EAH） was established in C57BL/6 mice and the expression levels of PD-1 and PD-L1, L2 in the murine liver and the cytokines, including interferon （IFN）-γ, tumor necrosis factor （TNF）-α and interleukin （IL）-4 in the spleen were detected using reverse transcription-polymerase chain reaction （RT-PCR）, and the results were compared with those of normal controls. Results The expression levels of PD-1, PD-L1, PD-L2 mRNA were higher in EAH compared with normal controls （P 〈0.05）, the PD-L2/PD-1 ratio was relatively lower in EAH （EAH -0.08±0.35, normal controls 0.52±0.07, P=0.009）. In the EAH, the expression of the three cytokines were all upregulated compared with normal controls. PD-L1 had a positive correlation with the expression of IFN-γ （r =0.289, P 〈0.05）, while PD-L2 showed a positive correlation with both expressions of IL-4 （r=0.378, P 〈0.01） and IFN-γ （r =0.261, P 〈0.05）. While TNF-α showed no correlation with PD-L1 （r=0.044, P=0.736） or PD-L2 （r=0.127, P=0.335）. Conclusions The expression of PD-1/PD-L1, L2 is upregulated in EAH and regulated by IFN-γ and IL-4. PD-1 system may play an important role in the pathogenesis of AIH.

Inhibition of MYC suppresses programmed cell death ligand-1 expression and enhances immunotherapy in triple-negative breast cancer

Background:Cancer immunotherapy has emerged as a promising strategy against triple-negative breast cancer(TNBC).One of the immunosuppressive pathways involves programmed cell death-1(PD-1)and programmed cell death ligand-1(PD-L1),but many patients derived little benefit from PD-1/PD-L1 checkpoint blockades treatment.Prior research has shown that MYC,a master transcription amplifier highly expressed in TNBC cells,can regulate the tumor immune microenvironment and constrain the efficacy of immunotherapy.This study aims to investigate the regulatory relationship between MYC and PD-L1,and whether a cyclin-dependent kinase(CDK)inhibitor that inhibits MYC expression in combination with anti-PD-L1 antibodies can enhance the response to immunotherapy.Methods:Public databases and TNBC tissue microarrays were used to study the correlation between MYC and PD-L1.The expression of MYC and PD-L1 in TNBCs was examined by quantitative real-time polymerase chain reaction and Western blotting.A patient-derived tumor xenograft(PDTX)model was used to evaluate the influence of a CDK7 inhibitor THZ1 on PD-L1 expression.Cell proliferation and migration were detected by 5-ethynyl-2′-deoxyuridine(EdU)cell proliferation and cell migration assays.Tumor xenograft models were established for in vivo verification.Results:A high MYC expression level was associated with a poor prognosis and could alter the proportion of tumor-infiltrating immune cells(TIICs).The positive correlation between MYC and PD-L1 was confirmed by immunostaining samples from 165 TNBC patients.Suppression of MYC in TNBC caused a reduction in the levels of both PD-L1 messenger RNA and protein.In addition,antitumor immune response was enhanced in the TNBC cancer xenograft mouse model with suppression of MYC by CDK7 inhibitor THZ1.Conclusions:The combined therapy of CDK7 inhibitor THZ1 and anti-PD-L1 antibody appeared to have a synergistic effect,which might offer new insight for enhancing immunotherapy in TNBC.

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

BACKGROUND 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.AIM To determine whether and how NAC-1 affects antitumor immunity in colon cancer.METHODS 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 controlshRNA 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.RESULTS 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.CONCLUSION Tumor expression of NAC-1 is a negative determinant of immunotherapy.

Immune checkpoint inhibitor therapy-induced autoimmune polyendocrine syndrome typeⅡand Crohn's disease:A case report

BACKGROUND The development of immune checkpoint inhibitors(ICIs)has heralded a new era in cancer treatment,enabling the possibility of long-term survival in patients with metastatic disease.Unfortunately,ICIs are increasingly implicated in the development of autoimmune diseases.CASE SUMMARY We present a man with squamous cell carcinoma of the oropharynx on a combination of teriprizumab,docetaxel,and cisplatin therapy who developed autoimmune polyendocrine syndrome typeⅡ(APS-2)including thyroiditis and type 1 diabetes mellitus and Crohn’s disease(CD).He developed thirst,abdominal pain,and fatigue after two-week treatment with the protein 1 ligand inhibitor teriprizumab.Biochemistry confirmed APS-2 and thyrotoxicosis.He was commenced on an insulin infusion.However,his abdominal pain persisted.Follow-up surgery confirmed CD and his abdominal pain was relieved by mesalazine.He was continued on insulin and mesalazine therapy.CONCLUSION Immunotherapy can affect all kinds of organs.When clinical symptoms cannot be explained by a single disease,clinicians should consider the possibility of multisystem damage.