Recurrent germline variant in ATM associated with familial myeloproliferative neoplasms

Genetic predisposition (familial risk) in the myeloproliferative neoplasms (MPNs) is more common than the risk observed in most other cancers, including breast, prostate, and colon. Up to 10% of MPNs are considered to be familial. Recent genome-wide association studies have identified genomic loci associated with an MPN diagnosis. However, the identification of variants with functional contributions to the development of MPN remains limited. In this study, we have included 630 MPN patients and whole genome sequencing was performed in 64 individuals with familial MPN to uncover recurrent germline predisposition variants. Both targeted and unbiased filtering of single nucleotide variants (SNVs) was performed, with a comparison to 218 individuals with MPN unselected for familial status. This approach identified an ATM L2307F SNV occurring in nearly 8% of individuals with familial MPN. Structural protein modeling of this variant suggested stabilization of inactive ATM dimer, and alteration of the endogenous ATM locus in a human myeloid cell line resulted in decreased phosphorylation of the downstream tumor suppressor CHEK2. These results implicate ATM, and the DNA-damage response pathway, in predisposition to MPN.

Transcriptomic Profiling and Pathway Analysis of Mesenchymal Stem Cells Following Low Dose-Rate Radiation Exposure

Low dose-rate radiation exposure can occur in medical imaging, as background from environmental or industrial radiation, and is a hazard of space travel. In contrast with high dose-rate radiation exposure that can induce acute life-threatening syndromes, chronic low-dose radiation is associated with Chronic Radiation Syndrome (CRS), which can alter environmental sensitivity. Secondary effects of chronic low dose-rate radiation exposure include circulatory, digestive, cardiovascular, and neurological diseases, as well as cancer. Here, we investigated 1-2 Gy, 0.66 cGy/h, ⁶⁰Co radiation effects on primary human mesenchymal stem cells (hMSC). There was no significant induction of apoptosis or DNA damage, and cells continued to proliferate. Gene ontology (GO) analysis of transcriptome changes revealed alterations in pathways related to cellular metabolism (cholesterol, fatty acid, and glucose metabolism), extracellular matrix modification and cell adhesion/migration, and regulation of vasoconstriction and inflammation. Interestingly, there was increased hypoxia signaling and increased activation of pathways regulated by iron deficiency, but Nrf2 and related genes were reduced. The data were validated in hMSC and human lung microvascular endothelial cells using targeted qPCR and Western blotting. Notably absent in the GO analysis were alteration pathways for DNA damage response, cell cycle inhibition, senescence, and pro-inflammatory response that we previously observed for high dose-rate radiation exposure. Our findings suggest that cellular gene transcription response to low dose-rate ionizing radiation is fundamentally different compared to high-dose-rate exposure. We hypothesize that cellular response to hypoxia and iron deficiency are driving processes, upstream of the other pathway regulation.

Abstract 2074: Germline mutation landscape of all DNA repair genes in African American prostate cancer patients

Introduction: DNA damage repair genes (DDRGs) play a critical role in genomic stability and their dysfunction contributes to mutagenesis in several cancer types. In prostate cancer (CaP) emerging data provide potential roles of DDR pathways in aggressive disease. However, the association with disease progression and therapeutic stratification based on inherited mutations of DDRGs remains to be defined in African American (AA) CaP patients. Our objective was to genomically profile all known annotated DDRGs in AA and Caucasian American (CA) CaP patient to determine whether DDRG germline variation status can refine patient stratification for targeted therapeutic options.

Methods: Germline mutations in all DDRGs (N=276) was evaluated by whole genome sequence (WGS) analysis of archived blood DNA samples from 600 CaP patients (300 AA and 300 CA) who underwent primary treatment at Walter Reed National Military Medical Center. The WGS mean coverage exceeded 37x. Principal Component Analysis (PCA) was used infer axes of genetic variation within AA men and examine individual and population clustering to predict ancestry of each sample using the Peddy program. Variant frequencies in CPDR CaP patients were compared to variant frequencies available from the Exome Aggregation Consortium (ExAC) control cases with no CaP by Fisher's Exact Test, using false discovery rate adjusted p-values.

Results: Interrogation of the complete known DDRG set of 276 genes revealed several known and novel mutations in this cohort. The Pathogenic/likely pathogenic (P/LP) variant carrier rate was higher than reported before (23.5%) in both AA and CA patients. However, the analysis revealed that more than 2/3 of the identified 47 DDRGs with P/LP mutation were different between AA and CA patients. Unlike in CA patients, several RAD family genes (RAD51, RAD54L, RAD54B), PMS2, and BRCA1 were among the most frequently mutated DDRGs in AA patients, but not in CA patients. The most frequent (over 1% carrier frequency) and potentially targetable type of mutations were independently validated by ddPCR. These genes are part of targetable DDRG pathways (homologous recombination and mismatch repair), suggesting that targeted therapy could potentially benefit AA patients. AA men harbor more potentially targetable DDRG germline mutations (over 10%) than CA men which may contribute to addressing CaP disparity. Germline mutations in any of the DDRG genes was associated with shorter time to BCR (Kaplan-Meier analysis, log rank p value 0.044) in AA patients, but not in CA patients.

Conclusion: Our findings highlight distinct racial differences in DDRGs and addresses the clinical utility by targeted therapy across AA and CA men. The percentage of patients with DDRG germline variation is of suitable threshold (23%) to consider early genetic testing for them in both AA and CA patients.

Citation Format: Indu Kohaar, Xijun Zhang, Shyh-Han Tan, Darryl Nousome, Kevin Babcock, Lakshmi Ravindranath, Gauthaman Sukumar, Elisa Mcgrath-Martinez, John Rosenberger, Camille Alba, Amina Ali, Denise Young, Yongmei Chen, Jennifer Cullen, Inger Rosner, Isabella Sesterhenn, Albert Dobi, Gregory Chesnut, Clesson Turner, Clifton Dalgard, Matthew Wilkerson, Shiv Srivastava, Gyorgy Petrovics. Germline mutation landscape of all DNA repair genes in African American prostate cancer patients [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2074.

Personalized Single-Cell Proteogenomics to Distinguish Acute Myeloid Leukemia from Non-Malignant Clonal Hematopoiesis

Genetic mutations associated with acute myeloid leukemia (AML) also occur in age-related clonal hematopoiesis, often in the same individual. This makes confident assignment of detected variants to malignancy challenging. The issue is particularly crucial for AML post-treatment measurable residual disease monitoring, where results can be discordant between genetic sequencing and flow cytometry. We show here, that it is possible to distinguish AML from clonal hematopoiesis and to resolve the immunophenotypic identity of clonal architecture. To achieve this, we first design patient-specific DNA probes based on patient's whole-genome sequencing, and then use them for patient-personalized single-cell DNA sequencing with simultaneous single-cell antibody-oligonucleotide sequencing. Examples illustrate AML arising from DNMT3A and TET2 mutated clones as well as independently. The ability to personalize single-cell proteogenomic assessment for individual patients based on leukemia-specific genomic features has implications for ongoing AML precision medicine efforts.

Distinguishing Smoking-Related Lung Disease Phenotypes Via Imaging and Molecular Features

BACKGROUND

Chronic tobacco smoke exposure results in a broad range of lung pathologies including emphysema, airway disease and parenchymal fibrosis as well as a multitude of extra-pulmonary comorbidities. Prior work using CT imaging has identified several clinically relevant subgroups of smoking related lung disease, but these investigations have generally lacked organ specific molecular correlates.

RESEARCH QUESTION

Can CT imaging be used to identify clinical phenotypes of smoking related lung disease that have specific bronchial epithelial gene expression patterns to better understand disease pathogenesis?

STUDY DESIGN AND METHODS

Using K-means clustering, we clustered participants from the COPDGene study (n = 5,273) based on CT imaging characteristics and then evaluated their clinical phenotypes. These clusters were replicated in the Detection of Early Lung Cancer Among Military Personnel (DECAMP) cohort (n = 360), and were further characterized using bronchial epithelial gene expression.

RESULTS

Three clusters (preserved, interstitial predominant and emphysema predominant) were identified. Compared to the preserved cluster, the interstitial and emphysema clusters had worse lung function, exercise capacity and quality of life. In longitudinal follow-up, individuals from the emphysema group had greater declines in exercise capacity and lung function, more emphysema, more exacerbations, and higher mortality. Similarly, genes involved in inflammatory pathways (tumor necrosis factor-α, interferon-β) are more highly expressed in bronchial epithelial cells from individuals in the emphysema cluster, while genes associated with T-cell related biology are decreased in these samples. Samples from individuals in the interstitial cluster generally had intermediate levels of expression of these genes.

INTERPRETATION

Using quantitative CT imaging, we identified three groups of individuals in older ever-smokers that replicate in two cohorts. Airway gene expression differences between the three groups suggests increased levels of inflammation in the most severe clinical phenotype, possibly mediated by the tumor necrosis factor-α and interferon-β pathways.

CLINICAL TRIAL REGISTRATION

COPDGene (NCT00608764), DECAMP-1 (NCT01785342), DECAMP-2 (NCT02504697).

Assessment of Statin Interactions With the Human NTCP Transporter Using a Novel Fluorescence Assay

Sodium taurocholate cotransporting polypeptide (NTCP), which is highly expressed in the sinusoidal membrane of hepatocytes, maintains bile acid homeostasis and participates in the hepatic disposition of a variety of endogenous substances as well as xenobiotics. Manifested by the involvement of organic anion-transporting polypeptides 1B1 and 1B3 (OATP1B1 and OATP1B3) in the hepatic uptake of statin drugs, sinusoidal membrane transporters play an important role in the pharmacokinetics and pharmacodynamics of these agents. It has been speculated that NTCP may function as an alternative pathway for statin hepatic uptake, complementary to OATP1B1 and OATP1B3. In the current study, we produced stable NTCP-expressing human embryonic kidney 293 (HEK293) cells and developed a fluorescence-based assay using flow cytometry for measuring NTCP transport with chenodeoxycholyl-(Nε-7-nitrobenz-2-oxa-1,3-diazole)-lysine (CDCA-NBD) as the substrate. NTCP-mediated CDCA-NBD transport was time-dependent and exhibited typical Michaelis-Menten kinetics, with a K _m of 6.12 µM. Compounds known to interact with NTCP, including chenodeoxycholic acid and taurocholic acid, displayed concentration-dependent inhibition of NTCP-mediated CDCA-NBD transport. We report here a systematic evaluation of the interaction between statins and the NTCP transporter. Utilizing this system, several statins were either found to inhibit NTCP-dependent transport or act as substrates. We find a good correlation between the reported lipophilicity of statins and their ability to inhibit NTCP. The objective was to develop a higher-throughput system to evaluate potential inhibitors such as the statins. The in vitro assays using CDCA-NBD as fluorescent substrate are convenient, rapid, and have utility in screening drug candidates for potential drug-NTCP interactions.

Abstract B075: Defining germline mutations of DNA damage repair genes in African American prostate cancer patients

Background: DNA damage repair genes (DDRGs) play a critical role in protecting genome integrity and have been implicated in several cancer types. In the context of prostate cancer (CaP) emerging data provide potential role of this pathway in aggressive disease. It has also been recently demonstrated that PARP inhibitors can extend overall survival in metastatic patients with DDRG mutations. However, the association and therapeutic stratification based on inherited mutations of DDRGs remains to be defined in African American (AA) CaP patients.

Our objective was to assess the frequency and association with disease aggressiveness of all known DDRGs in blood derived genomic DNAs of AA and Caucasian American (CA) CaP patients archived at the DOD Center for Prostate Disease Research and assess how this information can refine patient stratification for specific targeted therapeutic options.

Method: Germline mutations in all DDRGs was evaluated by whole genome sequence (WGS) analysis of archived blood DNA samples from 600 CaP patients (300 AA and 300 CA) who underwent primary treatment at Walter Reed National Military Medical Center (WRNMMC) over the past 20 years. These patients had equal access Department of Defense healthcare system with up to 20 years of follow-up time.

Following quality control steps to assess DNA quantity by Qubit assay and DNA quality by Bioanalyzer assay, DNA samples were used to generate PCR-free libraries for WGS using the NovaSeq (Illumina) platform. Out of the 600 libraries we generated, 14 dropped out, achieving a success rate of 97.6%. The successful libraries had an excellent quality based on DNA library metrics (yield and fragment length). Whole genome sequencing depth of the samples exceeded 37x on average and about 4 million SNPs were identified in the samples.

Patient genotypes were projected onto principal components from reference populations. Sample ancestries were predicted by using the “Peddy” program, which uses a machine learning model trained on individuals of diverse ancestries from the 1000 Genomes Project reference panel. Due to mismatched ancestry, 33 samples were excluded from further analyses. An additional 17 samples were excluded due to higher than minimal noise level based on analyses using “ContEst” tool from Broad GATK package and Illumina noise percent values.

Results: Interrogation of an inclusive DDRG set of 180 genes predicted to have non-silent effects on the protein sequence (e.g. missense, nonsense, frameshift) for germline mutations in this cohort revealed several known and novel mutations. The analysis has not been finalized yet. Mutation data will be assessed for association with the extensive available clinical and pathological data, including disease progression (metastasis), family history and African ancestry. Novel mutations, anticipated especially in the understudied AA context, will be analyzed for functional impact.

Citation Format: Kevin Babcock, Xijun Zhang, Matthew Wilkerson, Clifton L. Dalgard, Shyh-Han Tan, Lakshmi Ravindranath, Yongmei Chen, Jennifer Cullen, Shiv Srivastava, Inger L. Rosner, Gyorgy Petrovics. Defining germline mutations of DNA damage repair genes in African American prostate cancer patients [abstract]. In: Proceedings of the Twelfth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2019 Sep 20-23; San Francisco, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl_2):Abstract nr B075.

Region- and time-dependent gene regulation in the amygdala and anterior cingulate cortex of a PTSD-like mouse model

Posttraumatic stress disorder is developed by exposure to a threatening and/or a horrifying event and characterized by the presence of anxiety, hyperarousal, avoidance, and sleep abnormality for a prolonged period of time. To elucidate the potential molecular mechanisms, we constructed a mouse model by electric foot shock followed by situational reminders and performed transcriptome analysis in brain tissues. The stressed mice acquired anxiety-like behavior after 2 weeks and exaggerated startle response after 4 weeks. Avoidance latency and freezing behavior were sustained up to 5 weeks post stress and abnormal static behavior was observed during the sleep period. RNA sequencing was performed in two of the emotional regulatory regions, anterior cingulate cortex and amygdala, at 2 and 5 weeks post stress. More than 1000 differentially expressed genes were identified at 2 weeks in both regions. The number of the regulated genes remained constant in amygdala at 5 weeks post stress, whereas those in anterior cingulate cortex were plummeted. Although synaptic remodeling and endocrine system were the most enriched signaling pathways in both anterior cingulate cortex and amygdala, the individual gene expression profile was regulated in a region- and time-dependent manner. In addition, several genes associated with PTSD involved in Hypothalamic-Pituitary-Adrenal axis were differentially regulated. These findings suggested that global gene expression profile was dynamically regulated in accordance with the disease development stage, and therefore targeting the distinct signaling molecules in different region and development stage might be critical for effective treatment to PTSD.

Abstract 3248: Genomic characterization of premalignant lung squamous cell carcinoma lesions

Background: Lung squamous cell carcinoma (SqCC) arises in the epithelial layer of the bronchial airway and is often preceded by the development of premalignant lesions. However, not all premalignant lesions progress to lung SqCC and many will regress spontaneously. Understanding the somatic alterations and molecular subtypes associated with progression will allow us to identify biomarkers for early detection and develop therapeutic strategies for disease prevention and interception. Methods: Biopsies were obtained from high-risk smokers undergoing lung cancer screening by auto-fluorescence bronchoscopy and CT at the Roswell Park Cancer Institute. For each subject, multiple sites were sampled repeatedly over time. One biopsy from each region was sent for pathological review while another biopsy was taken for molecular studies. Whole-exome sequencing (WES) was performed at Uniform Services University to 120x coverage and RNA-seq was performed at Boston University School of Medicine. Results: The median number of somatic mutations across all premalignant lesions that underwent DNA-seq (150 biopsies from 20 subjects) was 0.45 per megabase and displayed a modest association with histological grade (p=0.05). The most frequently mutated known lung cancer genes included NOTCH1 (14%), TP53 (6%), FAT1 (3%), PIK3CA (2%), KRAS (<1%), and CDKN2A (<1%). One patient had a moderate dysplastic lesion without any detectable arm-level copy number changes or known cancer mutations. Six months later, this lesion had progressed to severe dysplasia and obtained many genomic alterations commonly observed in squamous cell carcinoma including 3q gain, 3p loss, and mutations in TP53, NOTCH1, and CDKN2A. Using RNA-seq, we identified 4 distinct molecular subtypes using 197 biopsies from 29 subjects. One subtype was enriched for samples with dysplasia histology, high basal cell content, and the “Classical” SqCC tumor gene expression subtype (p<0.001). These associations replicated in an independent set of 111 biopsies from 20 subjects. Genes associated with IFN-gamma signaling and T cell mediated immunity were down-regulated among lesions that persisted or progressed vs. those that regressed within the high-grade subtype. Staining of adjacent biopsies revealed that decreased expression of these immune pathways was associated with decreased numbers of CD4+ and CD8+ T cells within the lesions and surrounding tissue. Conclusions: The somatic alterations observed in known cancer genes may be among the earliest events in lung SqCC development and may be useful as biomarkers for early detection. Molecular classification of these lesions into molecular subtypes may lead to biomarkers of disease progression that could be used to identify at-risk patients for aggressive surveillance or for prevention trials.

Citation Format: Joshua D. Campbell, Xijun Zhang, Catalina Perdomo, Sarah Mazzilli, Yaron Geshalter, Samjot S. Dhillon, Gang Liu, Sherry Zhang, Hanqiao Liu, Jessica Vick, Christopher Moy, Stefano Monti, Evan Johnson, Matthew Meyerson, Matthew Wilkerson, Clifton Dalgard, Suso Platero, Chris Stevenson, Marc Lenburg, Mary Reid, Jennifer Beane, Avrum Spira. Genomic characterization of premalignant lung squamous cell carcinoma lesions [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 3248.

Abstract 5352: Racial/ethnic differences in prostate cancer genomic alterations

Background: Distinct biology of prostate cancer (CaP) among men of different races and ethnicities have been recently highlighted. Along these lines higher frequencies of the most common CaP gene alterations, ERG proto-oncogene activation and deletion of the PTEN tumor suppressor, have been reported among Caucasian Americans (CA) when compared to other racial/ethnic groups. We have reported the cumulative analyses of CaPs from 435 patients (whole genome sequencing (WGS), FISH evaluations and SNP arrays) that highlighted the recurrent deletion and disease progression association of the Limbic System-Associated Membrane Protein (LSAMP) in CaP genomes of African American (AA) men. Further examination of these data indicated the AA CaP genome associated recurrent deletion of the Chromodomain Helicase DNA Binding Protein 1(CHD1) gene.

Methods: Combined evaluation of frequencies and prognostic associations of ERG oncoprotein by immunohistochemistry and deletions of LSAMP, CHD1 and PTEN genes by FISH were performed using a multi-core TMA (42 AA and 59 CA patients) with longitudinal follow up data (median 16 years). CaP and matched blood genomic DNA samples (N=60) from AA patients were analyzed by WGS. ERG frequencies were further evaluated in index tumors of Chinese CaPs (N=100) and were compared to ERG frequencies in index tumors of AA (N=336) and CA (N=594) patients.

Results: Frequent deletions of CHD1 (29% AA vs. 10% CA p=0.017) and LSAMP (26% AA vs. 7% CA, p=0.006) were found in AA CaPs by FISH assay. Both of these deletions were associated with rapid disease progression. Evaluation of CaPs by WGS further highlighted the recurrent deletion of CHD1 among AA men. Comparative evaluation of ERG (AA, N=336; CA, N=594, and Asian N=100) underscored highest ERG frequencies among CA patients (49.3%) followed by AA (23.2%) and Chinese (22%) men.

Conclusions: In light of distinct biology of CaPs in ethnically/racially diverse CaP patient populations there is a need for developing broadly applicable diagnostic, prognostic marker panels and therapeutic approaches. Recurrent CHD1 deletion in CaPs of AA patients may provide new therapeutic opportunities in light of recent reports suggesting that CaP patients harboring CHD1 deletion may benefit from PARP inhibitor or platinum agents therapies. Funding: This study was supported by CPDR, USUHS, HU0001-10-2-0002 to I.L.R., the NCI/EDRN IAA ACN12011-001-0 to S.S. and by the NCI R01CA162383 to S.S.

Citation Format: Albert Dobi, Gyorgy Petrovics, Shyh-Han Tan, Hua Li, Denise Young, Cara Schafer, Jesse Fox, Kevin Babcock, Heng-Cheng Hu, Gauthaman Sukumar, Yingjie Song, Lakshmi Ravindranath, Yongmei Chen, Joseph Cheng, Reinhard Ebner, Qingyu Xiao, Yidi Sun, Yixue Li, Yuan Ji, Jun Hou, Wendy Wang, Guo-Ping Zhao, Jacob Kagan, Sudhir Srivastava, Joel T. Moncur, Clifton L. Dalgard, Matthew Wilkerson, Inger L. Rosner, Jennifer Cullen, Matthew Freedman, Zoltan Szallasi, Isabell A. Sesterhenn, Shiv Srivastava. Racial/ethnic differences in prostate cancer genomic alterations [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5352.

Abstract 3259: The genomic landscape of premalignant lung squamous cell carcinoma lesions

Background: Lung squamous cell carcinoma (SqCC) arises in the epithelial layer of the bronchial airway and is often preceded by the development of premalignant lesions. However, not all premalignant lesions progress to lung SqCC and many regress without therapeutic intervention. Understanding the somatic alterations that contribute to progression of premalignant lesions in the airway will allow us to identify biomarkers for early detection and develop therapeutic strategies for early intervention.

Methods: Airway biopsies were obtained from high-risk smokers undergoing lung cancer screening by auto-fluorescence bronchoscopy and chest CT at the Roswell Park Cancer Institute. For each subject (n=30), multiple premalignant lesions were sampled repeatedly over time (n=144 samples). One biopsy from each region was sent for pathological review while another biopsy was taken for molecular studies. DNA was also isolated from the blood or cytologically normal bronchial brushings to serve as a matched normal control. Exome capture was performed using the Illumina TruSeq Rapid Exome kit and sequenced to a mean depth of coverage of 120x at Uniform Services University and Walter Reed National Military Medical Center.

Results: The median number of somatic mutations across all premalignant lesions was 0.73 per megabase (range: 0.10 - 9.8 per Mb) and displayed a modest association with histological grade (p=0.07). The most frequently mutated lung cancer genes included KMT2C (12%), NOTCH1 (11%), FAT1 (6%), TP53 (5%), and CDKN2A (<1%). Known oncogenic hotspot mutations were observed in PIK3CA (1%) and KRAS (<1%). The majority of lesions did not have overlapping sets of mutations with other samples from the same patient, indicating that most of these lesions arose from clonally distinct populations. The two lesions with the relatively high mutation rates (>7/Mb) were taken from adjacent sites over two time points in the same individual with a prior history of lung squamous cell carcinoma. These lesions had a significantly overlapping set of mutations including FAT1 indicating a common evolutionary ancestor.

Conclusions: The somatic alterations observed in known cancer genes such as TP53, KMT2C, NOTCH1, and FAT1 may be among the earliest driver events in lung SqCC development and may be useful as biomarkers for early detection as well as targets for lung cancer interception.

Citation Format: Joshua Campbell, Xijun Zhang, Samjot S. Dhillon, Catalina Perdomo, Sarah Mazzilli, Yaron Geshalter, Gang Liu, Sherry Zhang, Hanqiao Lin, Jessica Vick, Christopher Moy, Stefano Monti, Evan Johnson, Matthew Meyerson, Steven Dubinett, Suso Platero, Matthew Wilkerson, Clifton Dalgard, Marc Lenburg, Mary Reid, Jennifer Beane, Avrum Spira. The genomic landscape of premalignant lung squamous cell carcinoma lesions [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3259. doi:10.1158/1538-7445.AM2017-3259

Rituximab: Uses in Dermatology

Rituximab is an anti-CD20 monoclonal antibody with considerable potential in dermatology due to an increase in off-label indications. Chronic graft-versus-host disease and pemphigus vulgaris are two of the most promising indications for off-label use of rituximab. It is a generally safe alternative that should be considered when traditional therapy with corticosteroids or immunosuppressants has failed or caused significant intolerance. Currently, rituximab is only FDA-approved for treatment of follicular and diffuse large B-cell non-Hodgkin's lymphoma, rheumatoid arthritis, chronic lymphocytic leukemia, granulomatosis with polyangiitis (formerly Wegener's granulomatosis) and microscopic polyangiitis. Herein, off-label uses of rituximab and its efficacy in the treatment of cutaneous diseases are reviewed.

Proteogenomics connects somatic mutations to signalling in breast cancer

Somatic mutations have been extensively characterized in breast cancer, but the effects of these genetic alterations on the proteomic landscape remain poorly understood. We describe quantitative mass spectrometry-based proteomic and phosphoproteomic analyses of 105 genomically annotated breast cancers of which 77 provided high-quality data. Integrated analyses allowed insights into the somatic cancer genome including the consequences of chromosomal loss, such as the 5q deletion characteristic of basal-like breast cancer. The 5q trans effects were interrogated against the Library of Integrated Network-based Cellular Signatures, thereby connecting CETN3 and SKP1 loss to elevated expression of EGFR, and SKP1 loss also to increased SRC. Global proteomic data confirmed a stromal-enriched group in addition to basal and luminal clusters and pathway analysis of the phosphoproteome identified a G Protein-coupled receptor cluster that was not readily identified at the mRNA level. Besides ERBB2, other amplicon-associated, highly phosphorylated kinases were identified, including CDK12, PAK1, PTK2, RIPK2 and TLK2. We demonstrate that proteogenomic analysis of breast cancer elucidates functional consequences of somatic mutations, narrows candidate nominations for driver genes within large deletions and amplified regions, and identifies therapeutic targets.

Abstract IA29: Proteogenomic and phosphoproteomic analysis of breast cancer

The genetic landscape of human breast cancer has been well defined in The Cancer Genome Atlas (TCGA) project. Mass spectrometry (MS)-based global proteome and phosphoproteome analyses provide a complementary, orthogonal approach to genomic studies to further improve the molecular taxonomy and biological understanding of breast cancer. We analyzed human breast cancer samples that had previously undergone comprehensive genomic and reversed phase protein array (RPPA) characterization by TCGA. Tumor samples were analyzed by global shotgun proteomics and phosphoproteomics at an unprecedented coverage of >11,000 quantified proteins and >27,000 phosphorylation sites for each tumor. We verified the translation of hundreds of genomically characterized single nucleotide and splice junction variants at the protein level. The correlation of mRNA to protein abundance was significant for 6,135 out of 9,302 protein/mRNA pairs, but differed amongst protein classes. Genes that did not correlate on the protein/mRNA level included components of basic cellular machineries such as the ribosome, RNA polymerase and spliceosome, as well as those involved in processes regulated by proteolysis. Hierarchical clustering yielded three major clusters in both the proteome and the phosphoproteome data: basal-enriched, luminal-enriched and stroma-enriched groups, the last also enriched for what have been previously designated “reactive-type” tumors by RPPA. Our deep proteome analysis promoted new insights including the consequences of chromosomal loss, such as the 5q deletion characteristic of basal-like breast cancer. The 5q trans effects were interrogated using the Library of Integrated Network-based Cellular Signatures. Theses analyses connected the 5q genes CETN3 and SKP1 to elevated expression of EGFR, and SKP1 also to SRC. Differential phosphopeptide analyses, integrated with activity maps derived from knock-in mutated cell lines, identified multiple novel downstream effects of PIK3CA and TP53 mutation. Besides ERBB2, other amplicon-associated, highly phosphorylated kinases were identified, including CDK12, PAK1, PTK2, RIPK2 and TLK2. These and other examples demonstrate that proteogenomic analysis of breast cancer elucidates functional consequences of somatic mutations, narrows candidate nominations for driver genes within large deletions and amplified regions, and identifies potential therapeutic targets.

Citation Format: Philipp Mertins, DR Mani, Kelly Ruggles, Michael Gillette, Karl Clauser, Pei Wang, Xianlong Wang, Jana Qiao, Song Cao, Francesca Petralia, Filip Mundt, Zhidong Tu, Jonathan Lei, Michael Gatza, Matthew Wilkerson, Charles Perou, Venkata Yellapantula, Kuan-lin Huang, Chenwei Lin, Michael McLellan, Ping Yan, Sherri Davies, Reid Townsend, Steven Skates, Jing Wang, Bing Zhang, Christopher Kinsinger, Mehdi Mesri, Henry Rodriguez, Li Ding, Amanda Paulovich, David Fenyo, Matthew Ellis, Steven Carr, NCI CPTAC. Proteogenomic and phosphoproteomic analysis of breast cancer. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Breast Cancer Research; Oct 17-20, 2015; Bellevue, WA. Philadelphia (PA): AACR; Mol Cancer Res 2016;14(2_Suppl):Abstract nr IA29.

IGF-1 Receptor Insufficiency Leads to Age-Dependent Attenuation of Osteoblast Differentiation

In the current study, we determined the effects of IGF-1 receptor haploinsufficiency on osteoblast differentiation and bone formation throughout the lifespan. Bone mineral density was significantly decreased in femurs of male and female Igf1r(+/-) mice compared with wild-type mice. mRNA expression of osteoblast differentiation markers was significantly decreased in femurs and calvariae from Igf1r(+/-) mice compared with cells from wild-type mice. Bone morphogenetic protein-7-induced ectopic bone in Igf1r(+/-) mice was significantly smaller with fewer osteoblasts but more lipid droplets and had reduced expression of osteoblast differentiation markers compared with wild-type mice. In bone marrow cells from middle-aged and old wild-type and Igf1r(+/-) male mice, palmitate inhibited osteoblast markers expression. In cells from young wild-type male mice, palmitate did not inhibit marker expression, but in cells from young male Igf1r(+/-) mice, palmitate inhibited bone sialoprotein and osterix but not osteocalcin or type I collagen (TIC). In female wild-type mice, palmitate inhibited osteoblast markers expression in cells from young, middle-aged, and old mice except TIC in cells from middle-aged mice. Palmitate inhibited bone sialoprotein expression in cells from middle-aged and old female Igf1r(+/-) mice and osteocalcin, osterix, and TIC expression in young and middle-aged female Igf1r(+/-) mice but stimulated expression in cells from old female Igf1r(+/-) mice. We conclude that IGF-1 receptor haploinsufficiency results in a prolipid accrual phenotype in bone in association with inhibition of growth factor-induced osteoblast differentiation, a situation which may phenocopy age-related decreases in bone formation.

Characterisation of immune responses in healthy foals when a multivalent vaccine protocol was initiated at age 90 or 180 days

REASONS FOR PERFORMING STUDY

Protection from infectious disease requires antigen-specific immunity. In foals, most vaccine protocols are delayed until 6 months to avoid maternal antibody interference. Susceptibility to disease may exist prior to administration of vaccination at age 4-6 months.

OBJECTIVES

The aim of this investigation was to characterise immune activation among healthy foals in response to a multivalent vaccine protocol and compare immune responses when foals were vaccinated at age either 90 or 180 days.

STUDY DESIGN

Randomised block design.

METHODS

Twelve healthy foals with colostral transfer were blocked for age and randomly assigned to vaccination at age 90 days (treatment) or at age 180 days (control). Vaccination protocols included a 3-dose series and booster vaccine administered at age 11 months.

RESULTS

Immune response following vaccination at age 90 or 180 days was comparable for several measures of cellular immunity. Antigen specific CD4+ and CD8+ expression of interleukin-4, interferon-γ and granzyme B to eastern equine encephalomyelitis, western equine encephalomyelitis, West Nile virus, tetanus toxoid, equine influenza and equine herpesvirus-1/4 antigens were evident for both groups 30 days after initial vaccine and at age 344 days. Both groups showed a significant increase in antigen-specific immunoglobulin G expression following booster vaccine at age 11 months, thereby indicating memory immune responses.

CONCLUSIONS

The data presented in this report demonstrate that young foals are capable of immune activation following a 3-dose series with a multivalent vaccine, despite presence of maternal antibodies. Although immune activation does not automatically confer protection, several of the immune indicators measured showed comparable expression in foals vaccinated at 3 months relative to control foals vaccinated at age 6 months. In high-risk situations where immunity may be required earlier than following a conventional vaccine series, our data provide evidence that foals respond to immunisation initiated at 3 months in a comparable manner to foals initiated at an older age.

Reproducible molecular characterization of non-small cell lung cancer from paraffin

7576

Background: Recommendations exist to aid the clinically relevant non-small cell lung cancer (NSCLC) classification of squamous (SQ) versus adenocarcinoma (AD), including immunohistochemistry (IHC) for TTF1 and p63. We hypothesize that PCR of RNA gene panels may improve the diagnostic accuracy over IHC. Methods: A multi-institutional cohort of NSCLC patients was abstracted for use of IHC in clinical practice. RNA was isolated from routine paraffin sections and a 54-gene Histology by gene Expression Predictor (HEP) was implemented to distinguish SQ, AD, and other NSCLC variants. IHC for TTF1 and p63 was obtained on a subset of patients in a standardized manner. To compare the reproducibility of PCR diagnostics to morphologic diagnosis, a subset of samples was processed as matched pairs from the same tumor, in blinded manner. Results: 493 clinical samples were analyzed from 419 patients. Pathologists obtained any IHC in 22% of the cases, with TTF1 or p63 in <10% of cases. In the subset of cases where standardized TTF1 and p63 was obtained, the stains were un-evaluable or incompletely obtained in 30% for reasons including technical failure, limited sample, and ambiguous staining (i.e positive for both p63 and TTF1); on this same subset, the HEP technical failure rate was 7%. In cases where staining was successful, both IHC and the HEP agreed with the clinical diagnosis at high rates (93 and 91% respectively). In IHC un-evaluable cases, slides were reviewed by up to 7 additional pathologists. In general such cases failed to produce a consensus diagnosis, suggesting that IHC failure indicates a difficult to diagnose case (kappa statistic <0.5). As another concordance assessment method, we evaluated a second diagnostic property, reproducibility, by taking paired samples from the same case for blinded review. Strikingly, morphologic review in a blinded manner by pathologist generated low agreement with overall agreement of 65% compared to the HEP agreement of 92%. Conclusions: PCR based diagnostics such as the HEP may improve NSCLC diagnostic performance

Abstract 5083: Analysis of head and neck cancer reveals recurrent copy number aberrations and molecular subtypes exhibiting distinct expression patterns of known oncogenes in the chr3q amplicon

Background: Head and neck squamous cell carcinoma (HNSCC) is a heterogeneous disease whose underlying etiology is unknown. Chung et al. (Cancer Cell 2004; 5: 489 - 500) detected HNSCC gene expression (GE) subtypes, but to our knowledge these subtypes have not been discovered in other HNSCC datasets. Moreover, we are not aware of any HNSCC studies that have examined recurrent DNA copy number (CN) aberrations in the context of GE subtypes. Numerous studies have shown that HNSCC exhibits recurrent copy number gains in chr3q26-28, a region that contains the known oncogenes SOX2, PIK3CA, and TP63. Bass et al. (Nature Genetics 2009; 41(11): 1238 - 1242) suggest that SOX2 plays a fundamental role in the development of esophageal SCC. However, it does not appear that the expression patterns of SOX2, PIK3CA, and TP63 have been investigated in HNSCC. Techniques: After receiving informed consent, we obtained tumor samples from an incident surgical series of HNSCC patients at the University of North Carolina Hospital. CN and GE assays were performed using Affymetrix Genome-Wide SNP6.0 and Agilent 44K Gene Expression platforms, respectively. GE subtypes were discovered using ConsensusClusterPlus, and their statistical significance was assessed with SigClust. DiNAMIC was used to detect recurrent CN aberrations. Results: Tumor samples from 169 patients were obtained, making this the largest genomic HNSCC series ever reported to our knowledge. After passing quality control on both platforms, GE data was available for 138 patients, while CN data was available for 110 patients; GE and CN data was available for 82 patients. Four GE subtypes were found, and all pairwise comparisons of these subtypes were statistically significant after adjusting for multiple testing. Nearest centroid methods show that our GE subtypes correspond to those of Chung et al.; three of our four GE subtypes show strong similarities to those found in lung squamous cell carcinoma. Overall, recurrent CN gains were discovered in chr3q27, chr11q13, and chr8q23; recurrent CN losses were found in chr3p21, chr9p21, and chr8p23. All of these regions harbor known oncogenes. Distinct patterns of recurrent gains and losses were noted when CN data from each GE subtype was examined, and different patterns of gain and loss were found when we examined CN data from each tumor site. Although the expression subtypes exhibit similar CN values in the chr3q26-28 amplicon, the expression patterns of SOX2, PIK3CA, and TP63 differ considerably. Conclusion: Integrated genomic analysis reveals HNSCC GE subtypes, some of which are present in lung cancer. The existence of distinct patterns of CN gain and loss in the GE subtypes suggests the presence of multiple biological pathways that play fundamental roles in the development of HNSCC.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5083. doi:1538-7445.AM2012-5083

Abstract 3939: Integrated genomic analysis of head and neck tumors reveals focal high-level copy number gains in chr11q13 are associated with increased expression of known regional oncogenes

Background: Head and neck squamous cell carcinoma (HNSCC) is a complex and heterogeneous disease for which the underlying genomic aberrations are unknown. Previous studies have suggested that chr11q13 is a region of interest in HNSCC. Independent studies suggest that genes from this region may be important – for example, CTTN, CCND1, MYEOV, and ANO1 – but to our knowledge no studies have focused on the integration of copy number data and potential targets, or investigated the prevalence of copy number aberrations (CNAs) and clinical covariates. Human papillomavirus-associated HNSCC (HPV-HNSCC) is of particular interest, and it is known that HPV-HNSCC is most commonly found in the oropharynx. However, to our knowledge no studies have examined the association between CNAs of chr11q13 and patient outcome for patients with oropharynx tumors.

Techniques: After receiving informed consent, we obtained tumor samples from an incident surgical series of HNSCC patients at the University of North Carolina Hospital. Copy number (CN) and gene expression (GE) assays were performed using Affymetrix Genome-Wide SNP6.0 and Agilent 44K Gene Expression platfoms, respectively. CN values were subsequently analyzed for amplifications in region of chr11q13 using an amplification threshold equivalent to at least a 50% increase in copy number.

Results: Samples from 162 patients were obtained, making this the largest genomic HNSCC series ever reported to our knowledge. After passing quality control on both platforms, CN, GE, and clinical data was available for 86 patients in the integrated analysis. Data from the remaining 76 samples was also reviewed, and for these samples either CN, GE, or clinical information is available. We estimate that amplifications of chr11q13 are found in approximately 30% of all HNSCC patients. The consensus region covers seven genes, and four of these genes – CTTN, CCND1, MYEOV, and ANO1 – have expression values that are statistically significantly correlated with copy number, supporting existing literature both for the region and these genes. If attention is restricted to patients with oropharynx tumors, we find that patients with chr11q13 amplifications have an increased risk of recurrence or death when compared to patients without chr11q13 amplifications. These amplifications are highly overlapping with smoking status in oropharynx patients, suggesting a potential mechanism for the worse outcome seen in HPV positive smokers relative to nonsmokers (N Eng J Med 2007;356:1944-1956).

Conclusion: Integrated genomic analysis unmasks frequent copy number gains in chr11q13. Copy number values in chr11q13 are associated with expression of known regional oncogenes. We suggest a potential explanation for the worse clinical outcomes seen in HPV positive smokers.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3939. doi:10.1158/1538-7445.AM2011-3939

Structural basis of light chain amyloidogenicity: comparison of the thermodynamic properties, fibrillogenic potential and tertiary structural features of four Vλ6 proteins

Primary (AL) amyloidosis results from the pathologic deposition of monoclonal light chains as amyloid fibrils. Studies of recombinant-derived variable region (VL) fragments of these proteins have shown an inverse relationship between thermodynamic stability and fibrillogenic potential. Further, ionic interactions within the VL domain were predicted to influence the kinetics of light chain fibrillogenicity, as evidenced from our analyses of a relatively stable Vlambda6 protein (Jto) with a long range electrostatic interaction between Asp and Arg side chains at position 29 and 68, respectively, and an unstable, highly fibrillogenic Vlambda6 protein (Wil) that had neutral amino acids at these locations. To test this hypothesis, we have generated two Jto-related mutants designed to disrupt the interaction between Asp 29 and Arg 68 (JtoD29A and JtoR68S). Although the thermodynamic stabilities of unfolding for these two molecules were identical, they exhibited very different kinetics of fibril formation: the rate of JtoD29A fibrillogenesis was slow and comparable to the parent molecule, whereas that of JtoR68S was significantly faster. High-resolution X-ray diffraction analyses of crystals prepared from the two mutants having the same space group and unit cell dimensions revealed no significant main-chain conformational changes. However, several notable side-chain alterations were observed in JtoR68S, as compared with JtoD29A, that resulted in the solvent exposure of a greater hydrophobic surface and modifications in the electrostatic potential surface. We posit that these differences contributed to the enhanced fibrillogenic potential of the Arg 68 mutant, since both Jto mutants lacked the intrachain ionic interaction and were equivalently unstable. The information gleaned from our studies has provided insight into structural parameters that in addition to overall thermodynamic stability, contribute to the fibril forming propensity of immunoglobulin light chains.

The effect of different bovine viral diarrhea virus genotypes and biotypes on the metabolic activity and activation status of bovine peripheral blood mononuclear cells

The effects of cytopathic (cp) and non-cytopathic (ncp) bovine viral diarrhea virus (BVDV) on the cellular metabolic activity and activation status of bovine peripheral blood mononuclear cells (PBMC) were investigated. Cellular DNA and protein synthesis was determined by [3H]thymidine and [3H]valine incorporation, respectively, in phytohemagglutinin (PHA)-stimulated PBMC. All cp strains and most ncp BVDV strains significantly inhibited DNA synthesis in PHA-stimulated PBMC; however, only cp BVDV strains inhibited protein synthesis. A plaque assay and immunofluorescence test confirmed productive BVDV infection of PBMC. In addition, viral RNA synthesis was demonstrated in BVDV-infected PBMC by RT-PCR. The interleukin-2 receptor (IL-2R) was used as a marker for the activation status of BVDV-infected PBMC. The expression of IL-2R was preserved in virus-infected cells, even though DNA and protein synthesis was suppressed. These findings suggest a novel mechanism of virus-induced immune suppression in which BVDV inhibits basic metabolic activities of bovine PBMC. The activation signals, however, are maintained.

A characterization of first-generation flowable composites

A plethora of new low-viscosity composite resin materials, or flowable composites, have been marketed during the last two years, but little has been published about them. The authors describe research in which they compared the properties--filler, depth or cure, flow, wear, compressive strength, diametral tensile strength, indented biaxial flexure strength and toughness--of flowable and hybrid composites. Mechanical property tests (ISO 4049, ISO/DIS 6872) of eight flowable composites and two hybrid composites were conducted. The flowable composite with the least flow was similar to traditional composites. Mechanical properties were generally about 60 to 90 percent of those of conventional composites. The authors conclude that flowable materials should be used with caution in high-stress applications for restorative dentistry.

Comparison of five agglutination tests for identification of Staphylococcus aureus

Various commercially produced agglutination kits are widely used for the identification of Staphylococcus aureus. These kits detect the presence of protein A and/or clumping factor on S. aureus. The literature has shown that methicillin-resistant S. aureus (MRSA) isolates which are deficient in both clumping factor and protein A may be misidentified. Two products, Slidex and Staphaurex Plus, utilize specific anti-S. aureus antibodies, potentially giving them greater sensitivity compared to products without these antibodies. We report a prospective study designed to compare the performance characteristics of Fastaph, Slidex, Staphaurex, Staphaurex Plus, Staphyloslide, and the tube coagulase test for the identification of staphylococcal isolates. All discrepant isolates were tested with the Gen-Probe AccuProbe S. aureus test and were identified to the species level with conventional reference biochemicals. A total of 1,193 isolates were tested, including 33 MRSA and 423 methicillin-sensitive S. aureus isolates. The sensitivities and specificities of the tests, respectively, were as follows: Fastaph, 99.1 and 98.9%; Slidex, 99.6 and 96.4%; Staphaurex, 98.9 and 99.9%; Staphaurex Plus, 99.6 and 93.9%; Staphyloslide, 99.1 and 98.9%; and tube coagulase, 99.3 and 100%. Sensitivity was excellent for all of the products tested. The specificities of Fastaph, Staphaurex, and Staphyloslide were excellent, while Staphaurex Plus and Slidex demonstrated less optimal results.

Four-week safety and efficacy study of dorzolamide, a novel, active topical carbonic anhydrase inhibitor

OBJECTIVE

To investigate the activity and local and systemic safety of the topical carbonic anhydrase inhibitor, dorzolamide hydrochloride.

DESIGN

Four-week, double-masked, randomized, placebo-controlled, parallel, three-center study.

SETTING

Referral centers.

PATIENTS

Forty-eight patients with bilateral open angle glaucoma or ocular hypertension and intraocular pressure (IOP) greater than 22 mm Hg entered the study. Two of 28 patients receiving dorzolamide and two of 20 patients receiving placebo were withdrawn due to adverse experiences.

INTERVENTION

Dorzolamide (2%) or placebo to each eye three times daily for 4 weeks.

MAIN OUTCOME MEASURES

Diurnal IOP curves; ophthalmologic evaluations including corneal ultrasound pachymetry and endothelial cell count; and systemic evaluations including vital signs, blood chemistries, complete blood cell counts, urinalysis, electrocardiogram, and drug and carbonic anhydrase activity levels in red blood cells.

RESULTS

Mean IOP at morning trough (8 AM) decreased from 27.1 mm Hg at baseline to 23.5 mm Hg on day 29 with dorzolamide (-13.3%) compared with a decrease from 27.1 mm Hg to 26.4 mm Hg with placebo (-2.3%). Peak activity occurred 2 hours after administration, with IOP decreasing from 26.8 mm Hg at baseline to 21.8 mm Hg on day 29 with dorzolamide (-18.4%) vs 26.1 mm Hg to 25.5 (-2.4%) with placebo. Mean corneal thickness was slightly increased for the dorzolamide-treated group compared with the placebo-treated group (0.009 mm vs 0.001 mm, respectively, P < .05) and changes in endothelial cell counts were similar (-24 cells/mm2 vs -27 cells/mm2, respectively, P > .25). Mean carbonic anhydrase isoenzyme II activity in red blood cells decreased to 21% of baseline in dorzolamide-treated patients. There were no clinically significant differences in ocular or laboratory parameters between the dorzolamide and placebo groups.

CONCLUSIONS

Dorzolamide demonstrated significant IOP lowering activity over 4 weeks. It was well tolerated and there were no clinically significant changes in ocular or systemic safety parameters.

Suppression of human corneal epithelial proliferation with breast carcinoma immunotoxin

We examined the effects of the immunotoxin 260F9 Mab-recombinant ricin A (developed against human breast carcinoma) on proliferating and confluent human corneal epithelium (HCE) cells in vitro. HCE cells derived from explants of discarded human donor corneoscleral rims were established as proliferating and confluent cell cultures, and were exposed continuously for 7 days to immunotoxin. Final cell counts at day 7, and thymidine uptake measured at days 1 and 7 postexposure, showed > 95% suppression of proliferating cells at an immunotoxin concentration of 10 ng/ml, with confluent HCE cells relatively unaffected. This immunotoxin may prove useful in treatment of proliferative ocular epithelial diseases such as epithelial downgrowth or squamous cell carcinoma of the ocular surface.

Inhibition of human corneal epithelium with immunotoxin 454A12-rRA

We examined the effects of the immunotoxin 454A12-rRa on proliferating and confluent human corneal epithelium (HCE) in vitro. Proliferating HCE was sensitive to 454A12-rRA in a dose-dependent fashion. At immunotoxin concentrations of 1,000 ng/ml for 7 days we observed an 86% reduction in cell counts. Confluent HCE was not sensitive to 454A12-rRA at equivalent concentrations of immunotoxin. These data confirm previous observations regarding selective sensitivity of proliferating ocular tissue to immunotoxin, but suggest that HCE is less sensitive to 454A12-rRA than other ocular cell types.

Inhibition of human subconjunctival fibroblast proliferation by immunotoxin

The ability to target proliferating cells is important for agents used to modulate wound healing by decreasing the growth of fibroblasts. Proliferating cells are known to express increased numbers of transferrin receptors and have increased receptor turnover. 454A12 Mab-rRA, an immunotoxin containing anti-human transferrin receptor monoclonal antibody conjugated to recombinant ricin A chain, was shown to inhibit the proliferation of human subconjunctival fibroblasts in vitro. A dose-related reduction of cell counts was observed in proliferating cells. More than 90% inhibition was achieved with an immunotoxin concentration of 10 ng/ml per 20,000 cells plated. In contrast, confluent fibroblasts were markedly less sensitive to the immunotoxin at equivalent concentrations. Comparative experiments demonstrated that 5-fluorouracil has less specificity for proliferating cells, with significant death of confluent fibroblasts at high drug concentrations.

Transscleral Nd:YAG laser cyclophotocoagulation with a contact lens

Transscleral Nd:YAG laser cyclophotocoagulation was performed on 100 consecutive patients. A contact lens designed specifically for this operation was used, and the results were compared to those of a previously reported series of 100 patients in which the same procedure was performed without the lens. The lens provided intraoperative advantages of eyelid separation, compression and blanching of the conjunctiva at the treatment site, and precise measurements for placement of the laser applications. Early postoperative advantages were reduced conjunctival burns and less hyperemia. However, the long-term results were comparable between the two series, with the exception of a higher incidence of phthisis when the lens was used. The thinning and blanching of the conjunctiva may increase the percentage of laser energy reaching the ciliary processes, which suggests a need for reduced energy levels when using the lens.