Cancer testis antigen burden (CTAB): a novel biomarker of tumor-associated antigens in lung cancer.

BACKGROUND: Cancer-testis antigens (CTAs) are tumor antigens that are normally expressed in the testes but are aberrantly expressed in several cancers. CTA overexpression drives the metastasis and progression of lung cancer, and is associated with poor prognosis. To improve lung cancer diagnosis, prognostic prediction, and drug discovery, robust CTA identification and quantitation is needed. In this study, we examined and quantified the co-expression of CTAs in lung cancer to derive cancer testis antigen burden (CTAB), a novel biomarker of immunotherapy response. METHODS: Formalin fixed paraffin embedded (FFPE) tumor samples in discovery cohort (n = 5250) and immunotherapy and combination therapy treated non-small cell lung cancer (NSCLC) retrospective (n = 250) cohorts were tested by comprehensive genomic and immune profiling (CGIP), including tumor mutational burden (TMB) and the mRNA expression of 17 CTAs. PD-L1 expression was evaluated by IHC. CTA expression was summed to derive the CTAB score. The median CTAB score for the discovery cohort of 170 was applied to the retrospective cohort as cutoff for CTAB "high" and "low". Biomarker and gene expression correlation was measured by Spearman correlation. Kaplan-Meier survival analyses were used to detect overall survival (OS) differences, and objective response rate (ORR) based on RECIST criteria was compared using Fisher's exact test. RESULTS: The CTAs were highly co-expressed (p < 0.05) in the discovery cohort. There was no correlation between CTAB and PD-L1 expression (R = 0.011, p = 0.45) but some correlation with TMB (R = 0.11, p = 9.2 × 10-14). Kaplan-Meier survival analysis of the immunotherapy-treated NSCLC cohort revealed better OS for the pembrolizumab monotherapy treated patients with high CTAB (p = 0.027). The combination group demonstrated improved OS compared to pembrolizumab monotherapy group (p = 0.04). The pembrolizumab monotherapy patients with high CTAB had a greater ORR than the combination therapy group (p = 0.02). CONCLUSIONS: CTA co-expression can be reliably measured using CGIP in solid tumors. As a biomarker, CTAB appears to be independent from PD-L1 expression, suggesting that CTAB represents aspects of tumor immunogenicity not measured by current standard of care testing. Improved OS and ORR for high CTAB NSCLC patients treated with pembrolizumab monotherapy suggests a unique underlying aspect of immune response to these tumor antigens that needs further investigation.

Genomic Profiling Reveals Differences in Primary Central Nervous System Lymphoma and Large B-Cell Lymphoma, With Subtyping Suggesting Sensitivity to BTK Inhibition.

BACKGROUND: B-cell primary central nervous system (CNS) lymphoma (PCL) is diffuse large B-cell lymphoma (DLBCL) confined to the CNS. Less than 50% of patients with PCL achieve complete remission with current therapies. We describe the findings from comprehensive genomic profiling (CGP) of a cohort of 69 patients with PCL, 36 cases of secondary CNS lymphoma (SCL), and 969 cases of DLBCL to highlight their differences and characterize the PCL cohort. In addition, we highlight the differences in frequency of germinal center B-cell like (GCB) and non-GCB subtypes and molecular subtypes, particularly MCD and EZH subtypes, between PCL and DLBCL. MATERIALS AND METHODS: Sixty-nine cases of B-cell PCL, 36 cases of secondary CNS lymphoma (SCL), and 969 cases of DLBCL were evaluated by CGP of 405 genes via DNAseq and 265 genes via RNAseq for fusions (FoundationOne Heme). Tumor mutational burden (TMB) was calculated from 1.23 Mb of sequenced DNA. RESULTS: Genomic alterations with significant differences between PCL and DLBCL included MYD88, ETV6, PIM1, PRDM1, CXCR4, TP53, and CREBBP, while only MYD88 was significantly different between SCL and DLBCL. PCL cases were significantly enriched for the MCD molecular subtypes, which have an excellent response to BTKi. We report a patient with a durable complete response to BTKi consistent with their genomic profile. EBV status, CD274 amplification, and TMB status suggest that 38% of PCL patients may benefit from ICPI; however further study is warranted. CONCLUSION: CGP of PCLs reveals biomarkers, genomic alterations, and molecular classifications predictive of BTKi efficacy and potential ICPI efficacy. Given the limitations of standard of care for PCL, CGP is critical to identify potential therapeutic approaches for patients in this rare form of lymphoma.

Genomic profiling of BCOR-rearranged uterine sarcomas reveals novel gene fusion partners, frequent CDK4 amplification and CDKN2A loss.

OBJECTIVE: Genomic alterations of BCOR via ZC3H7B-BCOR fusion or BCOR internal tandem duplication (ITD) define a subset of endometrial stromal sarcoma (ESS). The goals of this study were to: 1) determine the molecular landscape of BCOR-rearranged ESS, 2) to identify novel BCOR fusion gene partners in ESS and their associated clinicopathological characteristics, and 3) to potentially unravel targetable genomic alterations in BCOR-mutated ESS. METHODS: A retrospective database search of a CLIA-certified molecular laboratory was performed for uterine sarcomas that contained BCOR rearrangements or BCOR ITD. The cases were previously assayed by comprehensive genomic profiling via both DNA- and RNA-based targeted next generation sequencing during the course of clinical care. Clinicopathological and genomic data was centrally re-reviewed. RESULTS: We identify largest cohort of BCOR-rearranged ESS to date (n = 40), which included 31 cases with canonical ZC3H7B-BCOR fusion as well as 8 cases with novel BCOR gene rearrangement partners, such as BCOR-L3MBTL2, EP300-BCOR, BCOR-NUTM2G, BCOR-RALGPS1, BCOR-MAP7D2, RGAG1-BCOR, ING3-BCOR, BCOR-NUGGC, KMT2D-BCOR, CREBBP-BCOR and 1 case with BCOR internal rearrangement. Re-review of cases with novel rearrangements demonstrated sarcomas with spindle, epithelioid or small round cell components and frequent myxoid stromal change. Comprehensive genomic profiling revealed high frequency of CDK4 and MDM2 amplification in 38% and 45% of BCOR-rearranged cases, respectively, and homozygous deletion of CDKN2A, which encodes an inhibitor of CDK4 in 28% of cases. Notably, CDK4 and MDM2 amplification was absent in all cases from 15 different ESS cases harboring BCOR ITD. CONCLUSIONS: Alterations of CDK4 pathway members, for which targeted therapy is clinically available (i.e. palbociclib), via CDK4 amplification or CDKN2A loss, contributes to the pathogenesis of BCOR-rearranged uterine sarcomas, which may have therapeutic implications.

Genomic Landscape of Adult and Pediatric BCR-ABL1-Like B-Lymphoblastic Leukemia Using Parallel DNA and RNA Sequencing.

BCR-ABL1-like B-Acute Lymphoblastic Leukemia (B-ALL) is a subset of B-ALL with a poor prognosis that is found in all age groups. Definitive identification of these patients is difficult in routine clinical practice as gene expression profiling, the gold standard test, is not widely available. Comprehensive genomic profiling performed on 450 patients with extensive fusion profiling revealed a wide range of genomic alterations which were consistent with a classification of BCR-ABL1-like B-ALL in 29% of cases. This manuscript highlights a clinically available alternative method for identifying a large subset of patients with BCR-ABL1-like B-ALL.

SMARCA4 inactivation defines a subset of undifferentiated uterine sarcomas with rhabdoid and small cell features and germline mutation association.

A rare subset of aggressive SMARCA4-deficient uterine sarcomas has been recently proposed, with only a limited number of cases having been previously described. Here, we identify 16 additional cases of SMARCA4-deficient uterine sarcoma from the database of a large, CLIA-certified and CAP-accredited, reference molecular laboratory, and we expand on their clinicopathological and genomic features. Median patient's age was 49 years (range 32-70). Most tumors were aggressive with distant metastasis. SMARCA4-deficient uterine sarcoma demonstrated predominantly rhabdoid or large epithelioid cells with abundant cytoplasm, but also had varying degrees of small cell and spindle cell morphology. Tumors were microsatellite stable and exhibited no other or only few co-occurring genomic alterations by comprehensive genomic profiling. We discovered one patient, who developed SMARCA4-deficient uterine sarcoma at the age of 55, had a germline SMARCA4 mutation, whose daughter had previously died of small cell carcinoma of the ovary, hypercalcemic type, at the age of 32. Our data support the notion that SMARCA4 inactivation is the driver oncogenic event of a morphologically and molecularly distinct form of uterine sarcoma. Identification of SMARCA4-deficient uterine sarcomas may be clinically important due to their aggressive behavior, germline association, and emerging targeted therapies.

The Impact of Prior Single-Gene Testing on Comprehensive Genomic Profiling Results for Patients with Non-Small Cell Lung Cancer.

INTRODUCTION: Tissue-based broad molecular profiling of guideline-recommended biomarkers is advised for the therapeutic management of patients with non-small cell lung cancer (NSCLC). However, practice variation can affect whether all indicated biomarkers are tested. We aimed to evaluate the impact of common single-gene testing (SGT) on subsequent comprehensive genomic profiling (CGP) test outcomes and results in NSCLC. METHODS: Oncologists who ordered SGT for guideline-recommended biomarkers in NSCLC patients were prospectively contacted (May-December 2022) and offered CGP (DNA and RNA sequencing), either following receipt of negative SGT findings, or instead of SGT for each patient. We describe SGT patterns and compare CGP completion rates, turnaround time, and recommended biomarker detection for NSCLC patients with and without prior negative SGT results. RESULTS: Oncologists in > 80 community practices ordered CGP for 561 NSCLC patients; 135 patients (27%) first had negative results from 30 different SGT combinations; 84% included ALK, EGFR and PD-L1, while only 3% of orders included all available SGTs for guideline-recommended genes. Among patients with negative SGT results, CGP was attempted using the same tissue specimen 90% of the time. There were also significantly more CGP order cancellations due to tissue insufficiency (17% vs. 7%), DNA sequencing failures (13% vs. 8%), and turnaround time > 14 days (62% vs. 29%) than among patients who only had CGP. Forty-six percent of patients with negative prior SGT had positive CGP results for recommended biomarkers, including targetable genomic variants in genes beyond ALK and EGFR, such as ERBB2, KRAS (non-G12C), MET (exon 14 skipping), NTRK2/3, and RET . CONCLUSION: For patients with NSCLC, initial use of SGT increases subsequent CGP test cancellations, turnaround time, and the likelihood of incomplete molecular profiling for guideline-recommended biomarkers due to tissue insufficiency.

Patients with non-small cell lung cancer (NSCLC) should have their tumor tissue tested for all recommended biomarkers that can help identify their best treatment options. Traditional tests look at gene biomarkers one by one (single-gene testing), and doctors can order some or all these tests individually or in a group. However, some recommended biomarkers cannot be tested by traditional single-gene tests at all. Newer technology (next-generation sequencing) covers all current recommended treatment biomarkers in one test (comprehensive genomic profiling), but this testing is more expensive and can take more time. Our study shows that NSCLC patients do not get all recommended treatment biomarkers tested when a single-gene testing approach is taken. Single-gene testing also used up some patients' tumor tissue entirely, such that further testing by comprehensive genomic profiling could not be done at all (17% vs. 7% for patients with no prior single-gene tests), resulted in more sequencing failures (13% vs. 8%), and had turnaround time for results greater than 14 days for more patients (62% vs. 29%). When comprehensive genomic profiling was completed, 46% of patients with negative results from prior single-gene testing had positive results for recommended treatment biomarkers that were not included in the initial single-gene tests. To ensure that NSCLC patients receive testing for all recommended biomarkers, comprehensive genomic profiling must be performed first.

Real-world comprehensive genomic and immune profiling reveals distinct age- and sex-based genomic and immune landscapes in tumors of patients with non-small cell lung cancer.

Introduction: Younger patients with non-small cell lung cancer (NSCLC) (<50 years) represent a significant patient population with distinct clinicopathological features and enriched targetable genomic alterations compared to older patients. However, previous studies of younger NSCLC suffer from inconsistent findings, few studies have incorporated sex into their analyses, and studies targeting age-related differences in the tumor immune microenvironment are lacking. Methods: We performed a retrospective analysis of 8,230 patients with NSCLC, comparing genomic alterations and immunogenic markers of younger and older patients while also considering differences between male and female patients. We defined older patients as those ≥65 years and used a 5-year sliding threshold from <45 to <65 years to define various groups of younger patients. Additionally, in an independent cohort of patients with NSCLC, we use our observations to inform testing of the combinatorial effect of age and sex on survival of patients given immunotherapy with or without chemotherapy. Results: We observed distinct genomic and immune microenvironment profiles for tumors of younger patients compared to tumors of older patients. Younger patient tumors were enriched in clinically relevant genomic alterations and had gene expression patterns indicative of reduced immune system activation, which was most evident when analyzing male patients. Further, we found younger male patients treated with immunotherapy alone had significantly worse survival compared to male patients ≥65 years, while the addition of chemotherapy reduced this disparity. Contrarily, we found younger female patients had significantly better survival compared to female patients ≥65 years when treated with immunotherapy plus chemotherapy, while treatment with immunotherapy alone resulted in similar outcomes. Discussion: These results show the value of comprehensive genomic and immune profiling (CGIP) for informing clinical treatment of younger patients with NSCLC and provides support for broader coverage of CGIP for younger patients with advanced NSCLC.

Immunologic Factors Associated with Differential Response to Neoadjuvant Chemoimmunotherapy in Triple-Negative Breast Cancer.

Background: KEYNOTE-522 resulted in FDA approval of the immune checkpoint inhibitor pembrolizumab in combination with neoadjuvant chemotherapy for patients with early-stage, high-risk, triple-negative breast cancer (TNBC). Unfortunately, pembrolizumab is associated with several immune-related adverse events (irAEs). We aimed to identify potential tumor microenvironment (TME) biomarkers which could predict patients who may attain pathological complete response (pCR) with chemotherapy alone and be spared the use of anti-PD-1 immunotherapy. Methods: Comprehensive immune profiling, including RNA-seq gene expression assessment of 395 immune genes, was performed on matched FFPE tumor samples from 22 stage I-III TNBC patients (14 patients treated with neoadjuvant chemotherapy alone (NAC) and 8 treated with neoadjuvant chemotherapy combined with pembrolizumab (NAC+I)). Results: Differential gene expression analysis revealed that in the NAC group, IL12B and IL13 were both significantly associated with pCR. In the NAC+I group, LCK and TP63 were significantly associated with pCR. Patients in both treatment groups exhibiting pCR tended to have greater tumor inflammation than non-pCR patients. In the NAC+I group, patients with pCR tended to have greater cell proliferation and higher PD-L1 expression, while in the NAC group, patients with pCR tended to have lower cancer testis antigen expression. Additionally, the NAC+I group trended toward a lower relative dose intensity averaged across all chemotherapy drugs, suggesting that more dose reductions or treatment delays occurred in the NAC+I group than the NAC group. Conclusions: A comprehensive understanding of immunologic factors could potentially predict pCR to chemotherapy alone, enabling the avoidance of the unnecessary treatment of these patients with checkpoint inhibitors.

Genomic landscape of non-small-cell lung cancer with methylthioadenosine phosphorylase (MTAP) deficiency.

INTRODUCTION: New treatment strategies for advanced non-small-cell lung carcinoma (NSCLC) include synthetic lethality targets focused on protein arginine methyl transferases such as PRMT5 that exploit the impact of genomic loss of methylthioadenosine phosphorylase (MTAP). METHODS: Twenty nine thousand three hundred seventy nine advanced NSCLC cases underwent hybrid-capture based comprehensive genomic profiling between June 1, 2018 and May 31, 2020. PD-L1 expression was determined by immunohistochemistry (Dako 22C3 PharmDx assay). RESULTS: 13.4% (3928/29,379) NSCLC cases exhibited MTAP loss distributed in adenocarcinoma (59%), squamous cell carcinoma (22%), NSCLC not otherwise specified (16%), and 1% each for large-cell neuroendocrine, sarcomatoid, and adenosquamous carcinoma. Statistically significant differences in mitogenic driver alterations included more KRAS G12C mutations in MTAP-intact versus MTAP-lost (12% vs. 10%, p = 0.0003) and fewer EGFR short variant mutations in MTAP-intact versus MTAP-lost NSCLC (10% vs. 13%, p < 0.0001). Statistically significant differences in currently untargetable genomic alterations included higher frequencies of TP53 (70% vs. 63%, p < 0.0001) and RB1 inactivation (10% vs. 2%, p < 0.0001) in MTAP-intact compared to MTAP-lost NSCLC. SMARCA4 inactivation (7% vs. 10%, p < 0.0001) was less frequent in MTAP-intact versus MTAP-lost NSCLC. Alterations in ERBB2, MET, ALK, ROS1, and NTRK1 did not significantly differ between the two groups. Predictors of immunotherapy efficacy were higher in MTAP-intact versus MTAP-lost NSCLC including tumor mutational burden (9.4 vs. 8.6 mut/Mb, p = 0.001) and low (30% vs. 28%, p = 0.01) and high PD-L1 (32% vs. 30%, p = 0.01) expression. Alterations in biomarkers potentially predictive of immune checkpoint inhibitor resistance (STK11, KEAP1, and MDM2) were similar in the two groups. CONCLUSIONS: MTAP loss occurs in 13% of NSCLC, supporting the development of targeted therapies to exploit PRMT5 hyper-dependence. MTAP loss is accompanied by small differences in targeted and immunotherapy options which may impact future combination strategies.

Mechanisms of immune modulation in the tumor microenvironment and implications for targeted therapy.

The efficacy of cancer therapies is limited to a great extent by immunosuppressive mechanisms within the tumor microenvironment (TME). Numerous immune escape mechanisms have been identified. These include not only processes associated with tumor, immune or stromal cells, but also humoral, metabolic, genetic and epigenetic factors within the TME. The identification of immune escape mechanisms has enabled the development of small molecules, nanomedicines, immune checkpoint inhibitors, adoptive cell and epigenetic therapies that can reprogram the TME and shift the host immune response towards promoting an antitumor effect. These approaches have translated into series of breakthroughs in cancer therapies, some of which have already been implemented in clinical practice. In the present article the authors provide an overview of some of the most important mechanisms of immunosuppression within the TME and the implications for targeted therapies against different cancers.

Clinical characterization of the mutational landscape of 24,639 real-world samples from patients with myeloid malignancies.

Myeloid neoplasms represent a broad spectrum of hematological disorders for which somatic mutation status in key driver genes is important for diagnosis, prognosis and treatment. Here we summarize the findings of a targeted, next generation sequencing laboratory developed test in 24,639 clinical myeloid samples. Data were analyzed comprehensively and as part of individual cohorts specific to acute myeloid leukemia (AML), myelodysplastic syndrome (MDS), and myeloproliferative neoplasms (MPN). Overall, 48,015 variants were detected, and variants were found in all 50 genes in the panel. The mean number of mutations per patient was 1.95. Mutation number increased with age (Spearman's rank correlation coefficient, ρ = 0.29, P < 0.0001) and was higher in patients with AML than MDS or MPN (Student's t-test, P < 0.0001). TET2 was the most common mutation detected (19.1% of samples; 4,695/24,639) including 7.7% (1,908/24,639) with multi-hit TET2 mutations. Mutation frequency was correlated between patients with cytopenias and MDS (Spearman's, ρ = 0.97, P < 2.2×10-16) with the MDS diagnostic gene SF3B1 being the only notable outlier. This large retrospective study shows the utility of NGS testing to inform clinical decisions during routine clinical care and highlights the mutational landscape of a broad population of myeloid patients.

Predictive Biomarkers for Immune Checkpoint Inhibitors in Metastatic Breast Cancer.

We examined a large dataset of female metastatic breast cancers (MBCs) profiled with comprehensive genomic profiling (CGP) to identify the prevalence and distribution of immunotherapy responsiveness-associated biomarkers. DNA was extracted from 3831 consecutive MBCs: 1237 (ERpos /HER2neg ), 1953 ERneg /HER2amp , and 641 triple-negative breast cancer (TNBC). CGP was performed using the FoundationOne® or FoundationOne® CDx NGS assay. Tumor mutational burden (TMB) and microsatellite instability (MSI) were determined in a subset of cases. PD-L1 expression in immunocytes in a subset of cases was determined by immunohistochemistry using the companion diagnostic VENTANA PD-L1 SP142 Assay. The median age of the cohort was 54 years (range 20-89). Genomic alterations (GAs)/tumor were similar (range: 5.9-7.3). Markers of potential immune checkpoint inhibitor (ICPI) benefit included: CD274 (PD-L1) amplification (1%-3%), BRAF GA (1%-4%), TMB of ≥10 mutations/Mb (8%-12%), MSI-high (0.1%-0.4%), PBRM1 GA (1%), and positive PD-L1 staining of immunocytes ranging from 13% in ERpos /HER2neg and 33% in ERneg /HER2amp to 47% in the TNBC group. Potential markers of ICPI resistance included inactivating STK11 GA (1%-2%) and MDM2 amplification (3%-6%). MTOR pathway targets were common with lowest frequency in TNBC. ERBB2 short variant mutations were most frequent ERpos /HER2neg and absent in TNBC. BRCA1/2 GA were least frequent in ERneg /HER2amp . The demonstrations of clinical benefit of immunotherapy in MBC support the need for development and utilization of biomarkers to guide the use of ICPIs for these patients. In addition to guiding therapy selection, CGP shows potential to identify GA linked to response and resistance to ICPI in MBC.

Clinically Advanced Pheochromocytomas and Paragangliomas: A Comprehensive Genomic Profiling Study.

Patients with clinically advanced paragangliomas (CA-Para) and pheochromocytomas (CA-Pheo) have limited surgical or systemic treatments. We used comprehensive genomic profiling (CGP) to compare genomic alterations (GA) in CA-Para and CA-Pheo to identify potential therapeutic targets. Eighty-three CA-Para and 45 CA-Pheo underwent hybrid-capture-based CGP using a targeted panel of 324 genes. Tumor mutational burden (TMB) and microsatellite instability (MSI) were determined. The GA/tumor frequencies were low for both tumor types (1.9 GA/tumor for CA-Para, 2.3 GA/tumor for CA-Pheo). The most frequent potentially targetable GA in CA-Para were in FGFR1 (7%, primarily amplifications), NF1, PTEN, NF2, and CDK4 (all 2%) and for CA-Pheo in RET (9%, primarily fusions), NF1 (11%) and FGFR1 (7%). Germline mutations in known cancer predisposition genes were predicted in 13 (30%) of CA-Pheo and 38 (45%) of CA-Para cases, predominantly involving SDHA/B genes. Both CA-Para and CA-Para had low median TMB, low PD-L1 expression levels and none had MSI high status. While similar GA frequency is seen in both CA-Para and CA-Para, germline GA were seen more frequently in CA-Para. Low PD-L1 expression levels and no MSI high status argue against strong potential for novel immune checkpoint inhibitors. However, several important potential therapeutic targets in both CA-Para and CA-Para are identified using CGP.

Genomic Analysis of Circulating Tumor DNA in 3,334 Patients with Advanced Prostate Cancer Identifies Targetable BRCA Alterations and AR Resistance Mechanisms.

PURPOSE: Comprehensive genomic profiling (CGP) is of increasing value for patients with metastatic castration-resistant prostate cancer (mCRPC). mCRPC tends to metastasize to bone, making tissue biopsies challenging to obtain. We hypothesized CGP of cell-free circulating tumor DNA (ctDNA) could offer a minimally invasive alternative to detect targetable genomic alterations (GA) that inform clinical care. EXPERIMENTAL DESIGN: Using plasma from 3,334 patients with mCRPC (including 1,674 screening samples from TRITON2/3), we evaluated the landscape of GAs detected in ctDNA and assessed concordance with tissue-based CGP. RESULTS: A total of 3,129 patients (94%) had detectable ctDNA with a median ctDNA fraction of 7.5%; BRCA1/2 was mutated in 295 (8.8%). In concordance analysis, 72 of 837 patients had BRCA1/2 mutations detected in tissue, 67 (93%) of which were also identified using ctDNA, including 100% of predicted germline variants. ctDNA harbored some BRCA1/2 alterations not identified by tissue testing, and ctDNA was enriched in therapy resistance alterations, as well as possible clonal hematopoiesis mutations (e.g., in ATM and CHEK2). Potential androgen receptor resistance alterations were detected in 940 of 2,213 patients (42%), including amplifications, polyclonal and compound mutations, rearrangements, and novel deletions in exon 8. CONCLUSIONS: Genomic analysis of ctDNA from patients with mCRPC recapitulates the genomic landscape detected in tissue biopsies, with a high level of agreement in detection of BRCA1/2 mutations, but more acquired resistance alterations detected in ctDNA. CGP of ctDNA is a compelling clinical complement to tissue CGP, with reflex to tissue CGP if negative for actionable variants.See related commentary by Hawkey and Armstrong, p. 2961.

Glycogen Synthase Kinase 3 (GSK-3) influences epithelial barrier function by regulating occludin, claudin-1 and E-cadherin expression.

The Apical Junctional Complex (AJC) encompassing the tight junction (TJ) and adherens junction (AJ) plays a pivotal role in regulating epithelial barrier function and epithelial cell proliferative processes through signaling events that remain poorly characterized. A potential regulator of AJC protein expression is Glycogen Synthase Kinase-3 (GSK-3). GSK-3 is a constitutively active kinase that is repressed during epithelial-mesenchymal transition (EMT). In the present study, we report that GSK-3 activity regulates the structure and function of the AJC in polarized model intestinal (SK-CO15) and kidney (Madin-Darby Canine Kidney (MDCK)) epithelial cells. Reduction of GSK-3 activity, either by small molecule inhibitors or siRNA targeting GSK-3 alpha and beta mRNA, resulted in increased permeability to both ions and bulk solutes. Immunofluorescence labeling and immunoblot analyses revealed that the barrier defects correlated with decreased protein expression of AJC transmembrane proteins Occludin, Claudin-1 and E-cadherin without influencing other TJ proteins, Zonula Occludens-1 (ZO-1) and Junctional Adhesion Molecule A (JAM-A). The decrease in Occludin and E-cadherin protein expression correlated with downregulation of the corresponding mRNA levels for these respective proteins following GSK-3 inhibition. These observations implicate an important role of GSK-3 in the regulation of the structure and function of the AJC that is mediated by differential modulation of mRNA transcription of key AJC proteins, Occludin, Claudin-1 and E-cadherin.

Annexin A1 regulates intestinal mucosal injury, inflammation, and repair.

During mucosal inflammation, a complex array of proinflammatory and protective mechanisms regulates inflammation and severity of injury. Secretion of anti-inflammatory mediators is a mechanism that is critical in controlling inflammatory responses and promoting epithelial restitution and barrier recovery. AnxA1 is a potent anti-inflammatory protein that has been implicated to play a critical immune regulatory role in models of inflammation. Although AnxA1 has been shown to be secreted in intestinal mucosal tissues during inflammation, its potential role in modulating the injury/inflammatory response is not understood. In this study, we demonstrate that AnxA1-deficient animals exhibit increased susceptibility to dextran sulfate sodium (DSS)-induced colitis with greater clinical morbidity and histopathologic mucosal injury. Furthermore, impaired recovery following withdrawal of DSS administration was observed in AnxA1 (-/-) animals compared with wild-type (WT) control mice that was independent of inflammatory cell infiltration. Since AnxA1 exerts its anti-inflammatory properties through stimulation of ALX/FPRL-1, we explored the role of this receptor-ligand interaction in regulating DSS-induced colitis. Interestingly, treatment with an ALX/FPRL-1 agonist, 15-epi-lipoxin A4 reversed the enhanced sensitivity of AnxA1 (-/-) mice to DSS colitis. In contrast, 15-epi-lipoxin A4 did not significantly improve the severity of disease in WT animals. Additionally, differential expression of ALX/FPLR-1 in control and DSS-treated WT and AnxA1-deficient animals suggested a potential role for AnxA1 in regulating ALX/FPRL-1 expression under pathophysiological conditions. Together, these results support a role of endogenous AnxA1 in the protective and reparative properties of the intestinal mucosal epithelium.

Evidence for cross-reactivity of JAM-C antibodies: implications for cellular localization studies.

BACKGROUND INFORMATION: JAM-C (junctional adhesion molecule C) has been implicated in the regulation of leukocyte migration, cell polarity, spermatogenesis, angiogenesis and nerve conduction. JAM-C has been also reported to concentrate at TJs (tight junctions) and desmosomes, although detailed localization studies remain incomplete. RESULTS: Monoclonal (LUCA14, MAB1189, Gi11, and PACA4) and polyclonal (40-9000) antibodies were employed to evaluate JAM-C expression/localization in various epithelial cell lines. However, RT-PCR (reverse transcription-PCR) assays revealed no JAM-C mRNA in SK-CO15, HeLa and HPAF-II cells, whereas abundant mRNA was detected in platelets, Caco-2 and ARPE cells. Interestingly, immunofluorescence localization in all cells revealed strong intercellular junctional staining with all of the above antibodies, except PACA4. Given the positive staining results in cells lacking JAM-C mRNA, immunoblot analyses were performed. Western blots revealed a prominent protein band at 52 kDa in all cells tested with all antibodies except PACA4. However, the correct size of JAM-C (37 kDa) was only detected in cells containing JAM-C mRNA. Immunofluorescence staining of JAM-C mRNA-expressing Caco-2 cells using mAb PACA4 revealed co-localization with occludin and ZO-1 (zonula occludens 1) at TJs. Analyses by MS identified the cross-reactive 52 kDa protein band as K8 (keratin 8). Furthermore, siRNA (small interfering RNA)-mediated downregulation of K8 in JAM-C mRNA-negative cells resulted in diminished junctional staining along with a reduction in the intensity of the 52 kDa protein band. Using an antibody specific for K8 phosphorylated at Ser73, the 52 kDa protein was identified as this phosphorylated form of K8. CONCLUSIONS: The results from the present study demonstrate that a majority of available anti-human JAM-C antibodies cross-react with phosphorylated K8 and suggest that cellular localization studies using these reagents should be interpreted with caution. Of the JAM-C antibodies tested, only mAb PACA4 is monospecific for human JAM-C. Analyses using PACA4 reveal that JAM-C expression is variable in different epithelial cell lines with co-localization at TJs.

Identifying Opportunities and Challenges for Patients With Sarcoma as a Result of Comprehensive Genomic Profiling of Sarcoma Specimens.

PURPOSE: Comprehensive genomic profiling (CGP) of sarcomas is rapidly being integrated into routine clinical care to help refine diagnosis and prognosis and determine treatment. However, little is known about barriers to successful CGP or its clinical utility in sarcoma. We set out to determine whether CGP alters physician treatment decision-making, and whether sarcoma subtypes influence the frequency of successful technical performance of CGP. METHODS: A single-institution study evaluated profiling outcomes of 392 samples from patients with sarcoma, using a commercially available CGP panel. Of this group, 34 patients were evaluated prospectively (Decision Impact Trial) to evaluate the utility of CGP in physician decision-making. All cases were retrospectively analyzed to identify causes of CGP failure. RESULTS: CGP successfully interrogated 75.3% (n = 295 of 392) of patients with sarcoma. Bone sarcomas had lower passing rates at 65.3% (n = 32 of 49) compared with soft tissue sarcomas at 76.7% (n = 263 of 343; P = .0008). Biopsy location also correlated with profiling efficiency. Bone biopsy specimens had a 52.8% (n = 19 of 36) passing rate versus lung (61.1%; n = 33 of 54) and abdomen (80.1%; n = 109 of 136) specimens. CGP altered physician treatment selection in 25% of evaluable patients (n = 7 of 28) and was associated with improved progression-free survival. CONCLUSION: To our knowledge, this is the largest technical evaluation of the performance of CGP in sarcoma. CGP was effectively performed in the vast majority of sarcoma samples and altered physician treatment selection. Tumor location and tissue subtype were key determinants of profiling success and associated with preanalytic variables that affect DNA and RNA quality. These results support standardized biopsy collection protocols to improve profiling outcomes.