Higher mRNA Expression Research Articles

Targeting Myeloid Epithelial Tyrosine Kinase (MERTK) Receptor in Acute Myeloid Leukemia Using a Novel Antibody Drug Conjugate, Rgx-019-MMAE

Background: Myeloid epithelial reproductive tyrosine kinase receptor (MERTK) is a transmembrane protein receptor from the TAM (Tyro3, Axl, Mertk) family. It is known to be overexpressed in various solid and hematological cancers. Overexpression of MERTK is associated with reduced apoptosis, increased metastasis, and drug resistance in tumor cells, making it an attractive therapeutic target. RGX-019-MMAE, a novel humanized IgG1-MMAE antibody-drug conjugate (ADC) developed by Inspirna, selectively binds to MERTK on tumor cells, which results in internalization and degradation of the receptor, and induces cytotoxicity through the release of the payload, MMAE, which disrupts the mitosis process of actively dividing cells. Several monoclonal antibodies targeting MERTK have shown promising results against various solid cancers, however, the effect of targeting MERTK in AML progression via RGX-019-MMAE is not known. Here, we hypothesize MERTK is overexpressed in distinct subsets of AML and associated with leukemia progression, therefore, targeting MERTK via RGX-019-MMAE exerts an antileukemic effect. Methods: To determine the clinical/prognostic relevance of MERTK, we analyzed a gene expression dataset (OHSU) and segregated the patients into low and high MERTK mRNA expression groups based on their mean expression value. To identify the specific AML subset with the highest MERTK expression, MERTK protein expression was analyzed in 818 patients with AML by performing Reverse Phase Protein Arrays (RPPA). MERTK protein expression was also measured by flow cytometry in OCI-AML3, OCI-AML2, Kasumi-1, ThP-1, Molm-13, Molm-14, MV4-11, and U937 leukemic cell lines and in the peripheral blood or bone marrow of five AML patients. Further, we treated Kasumi-1 and OCI-AML3 AML cell lines with varying doses of RGX-019-MMAE or isotype control for 72 and 120 hours and measured its effect on AML cell viability using CellTiterGlo 2.0 assay. Likewise, we treated primary cells from 5 different AML patients and determined the anti-leukemic effect of RGX-019-MMAE in primary cells. Finally, we investigated the synergistic effect of RGX-019-MMAE with Venetoclax (BCL2 inhibitor) or 5-Azacytidine in vitro. Results: Analysis of AML OHSU dataset showed that patients with high MERTK mRNA expression had significantly worse overall survival than those having low MERTK mRNA expression (p=0.02). RPPA analysis revealed significantly higher MERTK protein expression in monocytic AML subtypes, such as M4 and M5, especially in those with PTPN11 mutation or t (9;11) translocation. Moreover, in the RPPA we noted that high expression of MERTK protein levels is significantly correlated with inferior survival. This finding suggests that MERTK could serve as a therapeutic target in AML, especially in patients with monocytic subtypes of leukemia. In addition, we observed varying degrees of MERTK protein expression in AML cell lines, with Kasumi-1 and OCI-AML3 expressing the highest amount of MERTK protein. Next, treatment of Kasumi-1 and OCI-AML3 cell lines with varying doses of anti-MERTK ADC, RGX-019-MMAE, resulted in significantly more killing of leukemic cells than the isotype control ADC in a dose-dependent manner (p<0.01), suggesting that RGX-019-MMAE inhibits AML cell proliferation. Further, we validated this finding in primary AML cells with high MERTK expression. As expected, we observed that treatment with RGX-019-MMAE induced significantly greater cell death (˜80% apoptosis) in leukemic cells than the isotype control ADC. In addition, Kasumi-1 and OCl-AML3 cells treated in combination with RGX-019-MMAE and either Venetoclax or 5-Azacytidine showed a synergistic effect with increased cytotoxicity in a dose-dependent manner. These findings suggest that RGX-019-MMAE targets MERTK-expressing leukemic cells, sensitizes cells to chemotherapies, and promotes overall cytotoxicity. Conclusion: RGX-019-MMAE significantly induced cell death in AML cell lines and primary AML patient samples. RGX-019-MMAE, combined with chemotherapeutic agents and targeted therapy, produces a synergistic anti-leukemic effect. Our data indicates that MERTK is a potential therapeutic target in AML patients with monocytic subtypes of leukemia.

Increased STX3 transcript and protein levels were associated with poor prognosis in two independent cohorts of esophageal squamous cell carcinoma patients.

Some conventional prognostic biomarkers for esophageal squamous cell carcinoma (ESCC) have the disadvantage that they have only been investigated at the level of either mRNA or protein levels or only in individual cohorts. Associations between Syntaxin 3 (STX3) expression and malignancy have been reported in several tumor types but not in ESCC. Here, we investigated the levels of both STX3 mRNA and protein, and its prognostic potential in two independent cohorts of patients with ESCC. STX3 mRNA levels were examined in surgical specimens by quantitative PCR in a cohort that included 176 ESCC patients. STX3 protein levels were investigated in surgically resected ESCC tissues by immunohistochemistry using tissue microarrays in a different cohort of 177 ESCC patients. Correlations were analyzed between the expression of STX3 mRNA and protein with clinicopathological factors and long-term prognosis. Quantitative PCR indicated a significant association between high level of STX3 mRNA expression and lymph node involvement, pathological stage, and poor overall survival. The multivariate analysis demonstrated that high STX3 mRNA expression was independently associated with poor overall survival outcomes. Immunohistochemistry revealed that STX3 protein expression in ESCC tissues and high STX3 protein expression were also significantly correlated with unfavorable overall survival. Overexpression of STX3 mRNA and protein may serve as potential prognostic biomarkers for ESCC patients.

REM-422, a Potent, Selective, Oral Small Molecule mRNA Degrader of the MYB Oncogene, Demonstrates Anti-Tumor Activity in Mouse Xenograft Models of AML

The c-MYB (MYB) oncogenic transcription factor is a key regulator of hematopoietic cell differentiation and proliferation. Recurrent genetic lesions or dysregulation of MYB have been identified in a variety of cancers, including adenoid cystic carcinoma (ACC), acute myeloid leukemia (AML), T-cell acute lymphoblastic leukemia (T-ALL), blastic plasmacytoid dendritic cell neoplasm (BPDCN), pediatric low-grade glioma (pLGG), and others. AML is characterized by multiple oncogenic abnormalities and high MYB mRNA expression. Evidence from in vitro and in vivo animal studies suggests that MYB may be a key downstream effector of these oncogenic abnormalities through the direct regulation of genes such as BCL2, MYC and FLT3. Functional genomics studies reveal MYB dependencies in human leukemia cell lines and mouse models of leukemia. Together, these data suggest that MYB is an attractive therapeutic target for AML and other hematological malignancies. Therapeutic agents that directly target MYB have yet to be developed, presumably due to the challenges of targeting this intrinsically disordered transcription factor, which lacks tractable ligand binding pockets. Here, we describe the mechanism of action and biological activity of REM-422, a potent, selective, oral small molecule messenger RNA (mRNA) degrader of MYB. REM-422 was identified through screening and medicinal chemistry efforts directed towards identifying small molecules that induce the inclusion of a normally unused ‘poison exon’ (PE), which contains a premature termination codon, into the MYB pre-mRNA transcript. Poison exon inclusion activates the nonsense-mediated decay pathway and promotes the degradation of MYB mRNA. We demonstrate in a cell-free assay that REM-422 acts by selectively facilitating the binding of the U1 snRNP spliceosome complex, which governs exon usage by recognizing 5‘ splice sites, to oligonucleotides containing the MYB PE 5‘ splice site sequence. REM-422 treatment of human leukemia cell lines promotes poison exon inclusion, leading to degradation of MYB mRNA and subsequent reduction in MYB protein levels (Figure 1A). In a panel of AML cell lines, REM-422 demonstrated preferential anti-proliferative activity in cell lines with high MYB expression, and in those shown to be MYB-dependent through functional genomics studies. To understand the pharmacokinetic (PK) and pharmacodynamic (PD) effects of MYB in vivo, Kasumi-1 AML cells were implanted subcutaneously in CB17 scid immunocompromised mice and REM-422 was dosed by oral gavage after the formation of established tumors. QD PO administration of REM-422 demonstrated dose-dependent effects in tumors on MYB mRNA levels, with induction of the MYB poison exon leading to reductions of MYB functional mRNA. In a 21-day study, REM-422 demonstrated significant anti-tumor activity, including tumor regressions at well tolerated dose levels (Figure 1 left). To further investigate the activity of REM-422, AML patient cells were injected into NOG immunocompromised mice and allowed to engraft. After successful engraftment, mice were dosed by oral gavage once daily with REM-422 at 10 mg/kg or vehicle for 24 days. Flow cytometry analysis of bone marrow and peripheral blood samples demonstrated that REM-422 led to the eradication of human leukemia cells from both compartments (Figure 1 right). Together, these data demonstrate that REM-422 treatment leads to degradation of MYB mRNA in preclinical models of AML and supports the therapeutic potential for REM-422 in AML patients.

The Role of G0S2 in Lipid Metabolism Regulation in Chronic Myeloid Leukemia

Introduction: Chronic myeloid leukemia (CML) can be effectively treated with tyrosine kinase inhibitors (TKIs) targeting BCR::ABL1, but resistance remains a clinical problem. TKIs do not target the quiescent CML leukemic stem cell (LSC), and many patients are treated for life at a high economic burden and sometimes with significant side effects. We recently published a tumor suppressor role for G0/G1 switch gene 2 (G0S2) in CML. Our data showed that loss of G0S2 expression in CML promoted disease progression and drug resistance by disrupting glycerophospholipid metabolism (Gonzalezet al. Clin Transl Med, 2022). Interestingly, G0S2 is an estrogen-response gene that demonstrated anti-estrogenic and pro-migratory effects in ER+ versus ER- breast cancer. Additionally, deletion of G0S2 prevented obesity and insulin resistance in mouse models. Since sex-based differences in lipid metabolism and obesity are well documented, we hypothesized that the tumor suppressor role of G0S2 in CML would differ based on sex. Methods: We used peripheral blood from wild-type and G0s2 knockout ( G0s2 -/-) mice (both male and female) who were fed with a normal versus a high-fat diet. Resulting lineage-negative (Lin-) cells were cultured in recombinant murine cytokines ± granulocyte-colony stimulating factor (mG-CSF, 25 ng/ml, 7-10 days) in in vitro differentiation assays. Flow cytometry analysis was performed to measure CD11b+ neutrophils. Additionally, we transduced Lin- cells from wild-type or G0s2 knockout mice with BCR::ABL1, and assessed their ability to form a leukemia-like disease process in male versus female recipient mice. We also performed G0S2 ectopic expression and knockdown experiments in the K562 CML cell line and assessed the resulting cells by liquid chromatography (LC)/mass spectrometry (MS)-based lipidomics and proteomics analyses. Immunoblots were performed to assess the resulting cells for changes in the autophagy markers, LC3A/B I-II. Results: For the experiments conducted with mouse peripheral blood, RT-qPCR data showed high G0S2 mRNA expression upon neutrophil differentiation in wild-type male mice (n=5), but not in the wild-type female mice (n=5). Flow cytometry measuring CD11b markers showed that a high-fat diet-induced neutrophil production in wild-type male mice, but not in wild-type female mice or G0s2 -/- mice, suggesting hormonal regulation involving G0S2 and female mice. Consistent with this observation, forced BCR::ABL1 expression in G0s2 -/- bone marrow reduced overall survival in female (n=4/group) but not male (n=5/group) mice compared with wild-type controls. In mass spectrometry-based lipidomics analyses, G0S2 knockdown resulted in a substantial decrease of di- and triglycerides. G0S2 knockdown also resulted in substantial changes in phosphatidylethanolamine and phosphatidylcholine expression, implicating G0S2 in the production of lipid bilayer components. Conversely, ectopic G0S2 expression promoted the accumulation of long- and very long-chain triglycerides and species of phosphatidylcholine and phosphatidylethanolamine in K562 cells. Proteomics analyses showed autophagy as one of the top pathways affected by altered G0S2 expression. When we measured LC3A/B I-II by immunoblot, we observed opposing effects comparing G0S2 ectopic expression versus knockdown. Conclusion: Altogether, these findings suggest sex-based differences in the role of G0S2 and lipid metabolism in CML stem and progenitor cell differentiation, survival, and autophagy, both in vitro and in vivo. Restoring G0S2 expression combined with BCR::ABL1 inhibition may be a novel clinical strategy to induce treatment-free remission in CML. However, further studies should assess whether this strategy will have similar effects in male versus female patients.

Pan-cancer analysis of PLAU indicates its potential prognostic value and correlation with neutrophil infiltration in BLCA

BackgroundPLAU is known as a selected serine protease converting plasminogen to plasmin. The role of PLAU in the development of pan-cancer, especially bladder urothelial carcinoma (BLCA) remains unclear. MethodA variety of online tools and cancer databases, including TCGA, GETx, HPA database, GSCALite, UALCAN, ESTIMATE, CIBERSORT, ssGSEA algorithms and SangerBox website, were applied to investigate the associations between PLAU expression and prognosis, genetic alterations, pathway activation, and tumor immunity in pan-cancer. Through cBioPortal and STITCH platforms, the oncogenic role of PLAU and related targeting medicines in BLCA were also explored. We verified the expression of PLAU in pan-cancer cells and its function in bladder cancer cell lines using wet-lab experiments. ResultsPLAU expression levels were significantly higher in most cancer tissues. PLAU had a certain accuracy in the diagnosis of various types of cancers (90 % AUC > 0.700). In BLCA, PLAU has abundant methylated sites and showed statistical differences in clinical features. PLAU was involved in tumor immune infiltration, and especially positively correlated with neutrophil infiltration. High-expressed PLAU indicated poorer prognosis in the BLCA patients receiving Atezolizumab. A high mRNA and protein expression levels of PLAU were observed in pan-cancer cell lines, especially BLCA cells. Knockdown of PLAU inhibited the invasive, proliferative, and aggressive phenotypes of bladder cancer cells. Immunohistochemical staining validated PLAU's higher expression in BLCA tissues than in adjacent non-cancerous tissues. And overexpression of PLAU was associated with more advanced TNM stage, and high infiltrating depth. ConclusionOur study revealed that PLAU can serve as a potential therapeutic target and prognostic marker for various malignancies, especially BLCA.

Differential expression of BCL11b and CDKN2A in CD30-positive peripheral T cell lymphoma: Retrospective study.

Peripheral T-cell lymphoma is a disease that includes multiple T-cell lymphoma subtypes. It is still unclear whether CD30 can be used as a new target molecule and classification standard for PTCL. Differences in the molecular characteristics of CD30-positive PTCL and CD30-negative PTCL have rarely been reported. This study aimed to analyze the expression of BCL11b and CDKN2A in CD30-positive PTCL and CD30-negative PTCL, in order to guide the pathological classification, prognosis, and clinical treatment of PTCL. Immunohistochemical staining and quantitative reverse-transcription PCR (qRT-PCR) were performed on formalin-fixed paraffin-embedded tissue. Verification of BCL11b and CDKN2A expression in ALCL, PTCL-NOS, AITL and NK/TCL. Based on immunohistochemical analysis, the expression level of BCL11b in the lymph node reactive hyperplasia control group was high at 85.0%, which was higher than 68.8% in CD30-positive PTCL and 44.1% in CD30-negative PTCL (P < .05, respectively). CDKN2A showed expression rates of 70.0% in the control group, 79.2% in CD30-positive PTCL and 79.4% in CD30-negative PTCL. qRT-PCR showed that the relative BCL11b mRNA expression levels in patients with PTCL were lower than those in the control group (0.694 vs 1.832, P = .045). Univariate analysis showed that international prognostic index score, CD30 expression, and BCL11b expression were closely related to prognosis (P < .05, respectively). Multivariate Cox regression analysis revealed that high expression of BCL11b mRNA was an independent factor affecting prognosis (respectively, P < .05). Spearman correlation analysis indicated that BCL11b expression had a significant positive correlation with CD30 expression (P = .005). These results indicate that BCL11b may be involved in CD30 differentiation and PTCL prognosis. The detection and targeting of BCL11b and CD30 may provide new strategies for the treatment and classification of PTCL.

TMUB1 expression is associated with the prognosis of colon cancer and immune cell infiltration.

TMUB1 is a transmembrane protein involved in biological signaling and plays an important role in the stability and transcription of P53. However, its role in tumor remains unknown. Using R language, the expression level of 33 cancer spectrum TMUB1 was analyzed by the public database TCGA, GEO and HPA, the differential expressed gene (DEG) screening and protein interaction (PPI) network was constructed, and the differential genes of TMUB1 in colon cancer were identified. The relevant signaling pathways were identified by gene functional annotation and enrichment analysis. The ssGSEA algorithm in GSVA were used for immune infiltration analysis. The Kaplan-Meier analysis, univariate and multivariate Cox regression analysis, nomogram and calibration map analysis were constructed to evaluate the correlation between TMUB1 expression and clinical prognosis. The expression levels of TMUB1 in intestinal cancer cell lines as well as in 10 intestinal cancer tissues were verified by qPCR experiments. Through the bioinformatics analysis of multiple databases and preliminary experimental studies, we found that the expression of TMUB1 was significantly increased in colon cancer tumors, and was correlated with the clinical N stage, pathological grade, lymphatic metastasis and BMI of colon cancer. TMUB1 may be involved in the regulation of the malignant progression of colon cancer. Meanwhile, patients with high expression of TMUB1 mRNA had worse OS and DSS, and TMUB1 expression was an independent prognostic factor for OS and DSS. It was further found that highly expressed TMUB1 tissues showed low levels of immune infiltration and stromal infiltration. We reported the expression level of TMUB1 in colon cancer and analyzed its potential prognostic value in colon cancer through the bioinformatics analysis and preliminary experimental studies. The high expression of TMUB1 is a negative prognostic factor for colon cancer patients. TMUB1 may be a potential target for colon cancer.

Continuous detrimental activity of intra-articular fibrous scar tissue in correlation with posttraumatic ankle osteoarthritis

Posttraumatic osteoarthritis is primarily characterized by articular cartilage destruction secondary to trauma or fracture events. Even while intra-articular scar tissue can be observed following ankle fractures, little is known about its nature and molecular events linking its biological activity and cartilage deterioration. Here, we investigated scar tissue's histological and molecular characteristics, and its relationship with localized articular cartilage alterations consistent with early osteoarthritic degeneration. Intra-articular scar tissues from sixty-two patients who underwent open reduction internal fixation for ankle fracture were obtained at hardware removal time (6–44 months after fracture). Histological analysis demonstrated that scar tissue has the nature of fibrosis with fibrous tissue hyperplasia, fibroblast proliferation, and chondrometaplasia. These fibrous scar tissues showed overexpressed pro-inflammatory cytokines and high mRNA expression levels of osteoarthritis-related markers (cytokines, chemokines, and enzymes) compared to the normal synovium. Furthermore, those transcriptional levels were significantly correlated with the grade of talar chondral degeneration. Our findings suggest that following an ankle fracture, the intra-articular fibrous scar tissue exhibits high catabolic and inflammatory activity, which has a long-lasting negative impact correlated to cartilage deterioration in the development of posttraumatic osteoarthritis.

Prognostic Potential of Galectin-9 mRNA Expression in Chronic Lymphocytic Leukemia.

Galectin-9 (Gal-9), very poorly characterized in chronic lymphocytic leukemia (CLL), was chosen in our study to examine its potential role as a CLL biomarker. The relation of Gal-9 expression in malignant B-cells and other routinely measured CLL markers, as well as its clinical relevance are poorly understood. Gal-9 mRNA expression was quantified with RT-qPCR in purified CD19+ B-cells of 100 CLL patients and analyzed in the context of existing clinical data. Our results revealed the upregulation of Gal-9 mRNA in CLL cells. High Gal-9 mRNA expression was closely associated with unfavorable prognostic markers. In addition, Gal-9 expression in leukemic cells was significantly elevated in CLL patients who did not respond to the first-line therapy compared to those who did respond. This suggests its potential predictive value. Importantly, Gal-9 was an independent predictor for the time to treatment parameters. Thus, we can suggest an adverse role of Gal-9 expression in CLL. Interestingly, it is possible that Gal-9 expression is induced in B-cells by EBV infection, so we determined the patients' EBV status. Our suggestion is that EBV coinfection could worsen prognosis in CLL, partly due to Gal-9 expression upregulation caused by EBV.

Chromosome-level genome assembly of the deep-sea snail Phymorhynchus buccinoides provides insights into the adaptation to the cold seep habitat

BackgroundThe deep-sea snail Phymorhynchus buccinoides belongs to the genus Phymorhynchus (Neogastropoda: Raphitomidae), and it is a dominant specie in the cold seep habitat. As the environment of the cold seep is characterized by darkness, hypoxia and high concentrations of toxic substances such as hydrogen sulfide (H2S), exploration of the diverse fauna living around cold seeps will help to uncover the adaptive mechanisms to this unique habitat. In the present study, a chromosome-level genome of P. buccinoides was constructed and a series of genomic and transcriptomic analyses were conducted to explore its molecular adaptation mechanisms to the cold seep environments.ResultsThe assembled genome size of the P. buccinoides was approximately 2.1 Gb, which is larger than most of the reported snail genomes, possibly due to the high proportion of repetitive elements. About 92.0% of the assembled base pairs of contigs were anchored to 34 pseudo‐chromosomes with a scaffold N50 size of 60.0 Mb. Compared with relative specie in the shallow water, the glutamate regulative and related genes were expanded in P. buccinoides, which contributes to the acclimation to hypoxia and coldness. Besides, the relatively high mRNA expression levels of the olfactory/chemosensory genes in osphradium indicate that P. buccinoides might have evolved a highly developed and sensitive olfactory organ for its orientation and predation. Moreover, the genome and transcriptome analyses demonstrate that P. buccinoides has evolved a sulfite-tolerance mechanism by performing H2S detoxification. Many genes involved in H2S detoxification were highly expressed in ctenidium and hepatopancreas, suggesting that these tissues might be critical for H2S detoxification and sulfite tolerance.ConclusionsIn summary, our report of this chromosome-level deep-sea snail genome provides a comprehensive genomic basis for the understanding of the adaptation strategy of P. buccinoides to the extreme environment at the deep-sea cold seeps.

MUC1-C Is a Common Driver of Acquired Osimertinib Resistance in NSCLC

IntroductionOsimertinib is an irreversible EGFR tyrosine kinase inhibitor approved for the first-line treatment of patients with metastatic NSCLC harboring EGFR exon 19 deletions or L858R mutations. Patients treated with osimertinib invariably develop acquired resistance by mechanisms involving additional EGFR mutations, MET amplification, and other pathways. There is no known involvement of the oncogenic MUC1-C protein in acquired osimertinib resistance. MethodsH1975/EGFR (L858R/T790M) and patient-derived NSCLC cells with acquired osimertinib resistance were investigated for MUC1-C dependence in studies of EGFR pathway activation, clonogenicity, and self-renewal capacity. ResultsWe reveal that MUC1-C is up-regulated in H1975 osimertinib drug-tolerant persister cells and is necessary for activation of the EGFR pathway. H1975 cells selected for stable osimertinib resistance (H1975-OR) and MGH700-2D cells isolated from a patient with acquired osimertinib resistance are found to be dependent on MUC1-C for induction of (1) phospho (p)-EGFR, p-ERK, and p-AKT, (2) EMT, and (3) the resistant phenotype. We report that MUC1-C is also required for p-EGFR, p-ERK, and p-AKT activation and self-renewal capacity in acquired osimertinib-resistant (1) MET-amplified MGH170-1D #2 cells and (2) MGH121 Res#2/EGFR (T790M/C797S) cells. Importantly, targeting MUC1-C in these diverse models reverses osimertinib resistance. In support of these results, high MUC1 mRNA and MUC1-C protein expression is associated with a poor prognosis for patients with EGFR-mutant NSCLCs. ConclusionsOur findings reveal that MUC1-C is a common effector of osimertinib resistance and is a potential target for the treatment of osimertinib-resistant NSCLCs.

Development of a New CAR-T-Cell Therapy Targeting an Immune Checkpoint for Effective Treatment of Solid and Liquid Tumors

Development of a new CAR-T-cell therapy against relapsed/refractory malignancies including solid tumors is an interest and a struggling issue. Immune-checkpoint blockade therapy is a successful modality for the treatment of solid tumors. We hypothesized that CAR-T-cell therapy targeting immune-checkpoint protein expressed by tumor cells results in involving T cells suppressed in tumor microenvironment as well as inducing direct cytotoxicity against tumor cells. Programmed cell death ligand 1 (PD-L1) is a major immune-checkpoint expressed by tumor cells. However, PD-L1 is also expressed by activated T cells, therefore it might not be straightforward as a target for CAR-T cells. Sialic-acid-binding immunoglobulin-like lectin 15 (SIGLEC15) is expressed by a panel of tumor cells including hematological malignancies, such as leukemia and lymphoma cells, and its expression in normal cells is limited to macrophages including myeloid-derived suppressor cells (MDSCs). Interestingly, it was reported that SIGLEC15 can suppress T-cell function in tumor microenvironment. Blocking therapy of SIGLEC15 using monoclonal antibody enhanced antitumor effects induced by T cells, thereby CAR-T-cell therapy for SIGLEC15 can be a new treatment modality targeting both an immune-checkpoint and tumor cells while evading cytokine release syndrome by targeting macrophages. Recently, we have developed a new strategy which is focusing on the optimization of a single chain fragment variable (scFv) important for the functions of CAR-T cells in vivo, therefore in this study, we have generated CAR-T cells expressing an optimized scFv for SIGLEC15 to achieve enhanced antitumor responses. First, SIGLEC15 mRNA expression was observed in a series of solid tumors using cDNA arrays. Particularly, ovarian cancer cells with moderate/poor characteristics had a trend of high expression of SIGLEC15 mRNA. Immunohistochemistry revealed that those ovarian cancer tissues were likely to express SIGLEC15 when compared to normal ovarian tissue. Next, variable regions of a monoclonal antibody specific for SIGLEC15 (SIGLEC15-VL, SIGLEC15-VH) were employed, and an scFv was integrated into a 2 nd generation CAR gene (CD28/CD3z). SIGLEC15 CAR-T cells recognized SK-OV-3, U87-MG cells from solid tumor cells, and Reh cells from liquid tumor cells, which was confirmed by ELISPOT assay, and were stained with in house soluble SIGLEC15 dimers. Then, using our technology, an scFv library which possessed variable regions of human immunoglobulin (hVK, hVL, or hVH) fused with SIGLEC15-VH or SIGLEC15-VL was generated, and re-integrated into the CAR gene. CAR-library T cells expressing an scFv library were stimulated with SIGLEC15 + antigen presenting cells, and SIGLEC15-specific population was isolated using soluble SIGLEC15 dimers after expansion. As the results, we have identified new clones of hVKs with SIGLEC15-VH. Among them, K145 CAR-T cells recognized and killed U87-MG and SK-OV-3 cell lines which express SIGLEC15, and were likely to proliferate well when compared to original CAR-T cells. Further analyses are needed, but these results suggest that SIGLEC15 might be an attractive target for new CAR-T-cell therapy, resulting in advancement of the treatment for solid and liquid tumors.

ABCB1 Regulates Immune Genes in Breast Cancer.

Resistance to standard chemotherapy is a critical problem for breast cancer patients. The ATP-binding cassette (ABC) superfamily transporters actively pump out drugs and play an important role in chemoresistance. ABCB1 (ABC subfamily B, member 1, also named as multidrug resistance protein 1, MDR1) and suppressive myeloid-derived suppressor cells (MDSCs) potentially involve in chemoresistance of breast cancer. The relationship between ABCB1 and immune genes in breast cancer has not been widely studied. Microarray and RNA sequencing data were obtained from The Cancer Genome Atlas Breast Invasive Carcinoma in Genomic Data Commons Data Portal and Gene Expression Omnibus database. A patient-derived xenograft (PDX) model of HER2+ breast cancer was established to investigate the association between ABCB1 and immune genes in breast cancer. Expression of ABCB1 increased in doxorubicin-selected MCF-7/ADR cells. High expression of ABCB1 mRNA is correlated with lymph-node metastasis and worse overall survival in patients with breast cancer. ABCB1 is positively correlated with IL6, CSF1, CSF3, and PTGS2. In the HER2+ stage IIA breast cancer PDX model, both doxorubicin and paclitaxel suppressed growth of P2 tumors. IL6, CSF1, CSF3, and PTGS2 expression were suppressed by paclitaxel but not doxorubicin. Intrasplenic MDSCs, including CD11b+Ly6G+ and CD11b+Ly6C+ cells, were more abundant than intratumor MDSCs in PDX-carrying nude mice. Clinically, the patient developed cancer recurrence after adjuvant chemotherapy with doxorubicin-based regimen and was well controlled after paclitaxel-trastuzumab combined therapy. ABCB1 was a poor predictor of HER2+ LN- breast cancer. Regulation of immune genes by ABCB1 contributed to cancer recurrence and treatment effect. The PDX model was suitable for investigation the expression of target genes and expansion of immune cells.

Acryl-3,5-bis(2,4-difluorobenzylidene)-4-piperidone targeting cellular JUN proto-oncogene, AP-1 transcription factor subunit inhibits head and neck squamous cell carcinoma progression.

Head and neck squamous cell carcinoma (HNSCC) is the seventh most common cancer worldwide with a survival rate below fifty percent. Addressing meager therapeutic options, a series of small molecule inhibitors were screened for antitumor efficacy. The most potent analog, acryl-3,5-bis(2,4-difluorobenzylidene)-4-piperidone (DiFiD; A-DiFiD), demonstrated strong cellular JUN proto-oncogene, activator protein 1 (AP-1) transcription factor subunit (JUN, c-Jun) antagonism. c-Jun, an oncogenic transcription factor, promotes cancer progression, invasion, and adhesion; high (JUN) mRNA expression correlates with poorer HNSCC survival. Four new small molecules were generated for cytotoxicity screening in HNSCC cell lines. A-DiFiD-treated HNSCC cells were assessed for cytotoxicity, colony formation, invasion, migration, and adhesion. Dot blot array was used to identify targets. Phospho-c-Jun (p-c-Jun) expression was analyzed using immunoblotting. The Cancer Genome Atlas (TCGA) head and neck cancer datasets were utilized to determine overall patient survival. The Clinical Proteomic Tumor Analysis Consortium (CPTAC) datasets interfaced with University of Alabama at Birmingham Cancer Data Analysis Portal (UALCAN) were analyzed to determine protein levels of c-Jun in HNSCC patients and correlate levels with patient. Of the small molecules tested, A-DiFiD was the most potent in HNSCC lines, while demonstrating low half-maximal drug inhibitory concentration (IC50) in non-malignant Het-1A cells. Additionally, A-DiFiD abrogated cell invasion, migration, and colony formation. Phospho-kinase in vitro array demonstrated A-DiFiD reduced p-c-Jun. Likewise, a time dependent reduction in p-c-Jun was observed starting at 3 min post A-DiFiD treatment. TCGA Firehose Legacy vs. recurrent and metastatic head and neck cancer reveal a nearly 3% DNA amplification in recurrent/metastatic tumor compared to below 1% in primary tumors that had no lymph node metastasis. CPTAC analysis show higher tumor c-Jun levels compared to normal. Patients with high JUN expression had significantly reduced 3-year survival. A-DiFiD targets c-Jun, a clinical HNSCC driver, with potent anti-tumor effects.

Expression of Matrix Metalloproteinases in the Circulating Immune Cells in Children with Helicobacter pylori Infection-Correlation with Clinical Factors.

H. pylori gastritis is strongly associated with the upregulation of the expression of several matrix metalloproteinases (MMPs) in the gastric mucosa. However, the role of MMP-2 and MMP-9, and their inhibitors (tissue inhibitors of metalloproteinases -TIMPs) produced by immune cells in infected children have not been clearly defined. Moreover, the effects of H. pylori eradication therapy on MMPs and TIMPs production has not been evaluated. A total of 84 children were studied: 24-with newly diagnosed H. pylori gastritis, 25-after H. pylori eradication therapy (17 of them after successful therapy), 24-with H. pylori-negative gastritis, and 11-controls. Plasma levels of MMP-2, MMP-9, TIMP-1, and TIMP-2 by ELISA; MMPs and TIMPs expression in lymphocytes; neutrophils and monocytes in peripheral blood by multiparameter flow cytometry; and mucosal mRNA expression levels of MMPs and TIMP-1 in gastric biopsies by RT-PCR were evaluated. Children with H. pylori-related gastritis showed the following: (1) increased MMP-2 and TIMP-2 plasma levels, (2) increased intracellular expression of MMP-2 in the circulating lymphocytes and neutrophils, (3) low frequencies of circulating TIMP-1+ and TIMP-2+ leukocytes, and (4) high expression of mRNA for MMP-9 along with low expression of mRNA for MMP-2 in the gastric mucosa. Unsuccessful H. pylori eradication was associated with the following: (1) high plasma levels of MMP-9 and TIMP-1, (2) increased pool of TIMP-1+ lymphocytes as well as high expression of MMP-9 in circulating lymphocytes, and (3) high expression of mRNA for MMP-9 in the gastric mucosa. Our data suggest that MMPs are important contributors to stomach remodelling in children with H. pylori-related gastritis. Unsuccessful H. pylori eradication is associated with increased MMP-9 in plasma, circulating lymphocytes, and gastric mucosa.

DLL3 Is a Prognostic and Potentially Predictive Biomarker for Immunotherapy Linked to PD/PD-L Axis and NOTCH1 in Pancreatic Cancer.

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive neoplasm with very poor patient survival outcomes despite available treatments. There is an urgent need for new potential treatment options and novel biomarkers for these patients. Delta-like canonical Notch ligand 3 (DLL3) interacts with the Notch receptor and causes inhibition of Notch signaling, which confers a survival advantage to PDAC cells. Thus, DLL3 expression could affect cell survival, and its inhibition could increase a patient's survival. To test this hypothesis, a survival analysis was conducted using the progression-free and overall survival from two independent datasets of PDAC patients, with one using mRNA z-score levels and the other using the Hscore protein expression level; both were carried out using a log-rank test and plotted using Kaplan-Meier curves. DLL3 at the mRNA expression level showed an association between high mRNA expression and both a longer progression-free survival (PFS) and overall survival (OS) of patients. Then, we designed a retrospective study with resected PDAC samples. Our primary objective with this dataset was to assess the relationship between PFS and OS and DLL3 protein expression. The secondary assessment was to provide a rationale for the use of anti-DLL3-based treatments in combination with immunotherapy that is supported by the link between DLL3 and other factors that are involved in immune checkpoints. The survival analyses revealed a protective effect of high DLL3 protein expression levels in both PFS and OS. Interestingly, high DLL3 protein expression levels were significantly correlated with PD-L1/2 and negatively correlated with NOTCH1. Therefore, DLL3 could be considered a biomarker for better prognosis in resectable PDAC patients as well as a therapeutic biomarker for immunotherapy response. These facts set a rationale for testing anti-DLL3-based treatments either alone or combined with immunotherapy or other NOTCH1 inhibitors.

Immunological function and prognostic value of lymphoid-specific helicase in liver hepatocellular carcinoma.

Lymphoid-specific helicase (HELLS), a SNF2-like chromatin-remodeling enzyme, plays a key role in tumor progression via its DNA methylation function. However, the effects of HELLS on immune infiltration and prognosis in liver hepatocellular carcinoma (LIHC) remain uncertain. The Tumor Immune Estimation Resource (TIMER) database was employed to explore the pan-cancer mRNA expression of HELLS and its correlation with immunity. GEPIA2 was used to verify the correlation between HELLS expression and survival. The role of HELLS in cancer was explored via gene set enrichment analysis (Gene Ontology and Kyoto Encyclopedia of Genes and Genomes) and the construction of gene-gene and protein-protein interaction networks (PPI). Additionally, correlations between DNA methylation, HELLS expression, and immune-related genes were explored in LIHC. HELLS expression in LIHC clinical samples was determined using qRT-PCR and western blotting. The effects of downregulated HELLS expression in hepatocellular carcinoma cells was explored via transfection experiments in vitro. High HELLS mRNA expression was identified in several cancers and was significantly associated with poorer prognosis in LIHC. Furthermore, HELLS expression was positively correlated with tumor-infiltrating lymphocytes and immune checkpoint genes in LIHC. Bioinformatics analysis suggested that DNA methylation of HELLS may be associated with the immune response. Results from the TCGA-LIHC dataset, clinical samples, and functional analysis indicated that HELLS contributed to tumor progression in LIHC. The study findings demonstrate that HELLS is an important factor in promoting LIHC malignancy and might serve as a potential biomarker for LIHC.

Two Distinct Characteristics of Immune Microenvironment in Human Hepatocellular Carcinoma with Wnt/β-Catenin Mutations

Introduction: Immunotherapy is becoming a promising approach for unresectable-hepatocellular carcinoma (HCC); the anti-tumor response is affected by the tumor microenvironment (TME). Although Wnt/β-catenin mutations are reported to cause non-inflamed phenotype, their role on TME remains controversial. We aimed to clarify the heterogeneity of immunophenotype in HCC with Wnt/β-catenin mutations. Methods: This study includes 152 resected HCCs; mutations in the catenin beta-1, adenomatous polyposis coli, or AXIN1, or AXIN2 genes were defined as Wnt/β-catenin mutations. With hierarchical cluster analyses, TME was classified into inflamed or non-inflamed classes based on the gene expressions associated with T-cell activation. Expression profiles of molecules related to cell differentiation and biliary-stem cell markers were compared between the TME classes to investigate whether differences in tumor traits were associated with TME. Results: Forty of 152 (26.3%) HCCs carried the Wnt/β-catenin mutations. Of these, 33 were classified as non-inflamed (33/40, 82.5%) and 7 as inflamed (7/40, 17.5%). Non-inflamed class was characterized by low number of CD3+, CD4+, and CD8+ cells on immunostaining, and high mRNA expressions of AXIN2 and GLUL, which are involved in the canonical Wnt/β-catenin signaling and hepatocyte differentiation, respectively. Non-inflamed tumors showed higher enhancement on the hepatobiliary-phase of gadolinium-ethoxybenzyl-diethylenetriamine (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI) compared to inflamed tumors. HCCs classified as inflamed class are revealed to have high numbers of CD3+, CD4+, and CD8+ tumor infiltrating lymphocytes on immunostaining. This class is associated with increased expression of anti-epithelial cell adhesion molecule and FOXM1 accompanied by upregulation of genes related to interferon-gamma signaling, dendritic cell migration, regulatory T cells, and myeloid-derived suppressor cell activation and recognized as low enhancement nodule on Gd-EOB-DTPA-enhanced MRI. Conclusion: Heterogeneity of tumor traits and TME was observed in HCC with Wnt/β-catenin mutation. The potential was indicated that tumor traits and TME are determined not only by the activation of the HNF4A but also by FOXM1, both of which are downstream transcription factor of the Wnt/β-catenin signaling pathway.

Hypoxia-inducible factor 2α protein and mRNA expression correlate with histomorphological features in clear cell renal cell carcinoma

Hypoxia-inducible factor 2α (HIF2α) has been identified as a potential biomarker and novel target for systemic therapy in clear cell renal cell carcinoma (ccRCC). The present study aims to evaluate the association of HIF2α protein and HIF2A mRNA expression with clinicopathological factors and histomorphological features related to vasculature and inflammation of ccRCC using a localized ccRCC cohort (n = 428) and The Cancer Genome Atlas (TCGA)-KIRC cohort (n = 433). HIF2α protein expression was immunohistochemically assessed using tissue microarrays and HIF2A mRNA expression was assessed using the TCGA RNA-sequencing data. Positive HIF2α protein and high HIF2A mRNA expression were observed in 145 (33.9 %) and 142 (32.8 %) patients, respectively. Positive nuclear HIF2α protein expression was significantly associated with the clear histological phenotype and architectural patterns related to rich vascular networks (p < 0.001), and no tumor-associated immune cells status (p < 0.05) in addition to favorable prognostic factors such as lower TNM stage, lower WHO/ISUP grade, or the absence of necrosis (p < 0.001). The HIF2A mRNA expression profile by the TCGA cohort showed similar trends as the HIF2α protein profile. In addition, positive HIF2α protein and high HIF2A mRNA expression were associated with higher recurrence-free survival and overall survival, respectively (both p < 0.001). In conclusion, we comprehensively demonstrated the association of HIF2α profiles with clinicopathological factors and histomorphological features related to vasculature and inflammation at both protein and mRNA levels. Histomorphological features expressing HIF2α may provide information on HIF2α targeted therapeutic response as well as prognosis in ccRCC patients.

2309P High DDR1 mRNA and protein expression across human tumor types correlate with epithelial composition of the tumor microenvironment

2309P High DDR1 mRNA and protein expression across human tumor types correlate with epithelial composition of the tumor microenvironment