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1.
Br J Haematol ; 204(2): 638-643, 2024 02.
Article in English | MEDLINE | ID: mdl-37571963

ABSTRACT

Immune thrombotic thrombocytopenic purpura (iTTP) is a rare and life-threatening haematological condition. Initial treatment involves plasma exchange (PLEX), corticosteroids, caplacizumab and rituximab. In relapsed and refractory cases despite initial treatments, further immune-modulating therapy includes the proteasome inhibitor, bortezomib. Evidence for bortezomib in this setting is limited to case reports and case series. We report our experience and perform a systematic review of the literature. We identified 21 publications with 28 unique patients in addition to our cohort of eight patients treated with bortezomib. The median age of patients was 44 years (IQR: 27-53) and 69% female. They were usually in an initial, refractory presentation of iTTP where they had received PLEX, corticosteroids, rituximab and another line of therapy. After bortezomib administration, 72% of patients had a complete response, with 85% maintaining a durable response without relapse at the last follow-up.


Subject(s)
Purpura, Thrombocytopenic, Idiopathic , Purpura, Thrombotic Thrombocytopenic , Humans , Female , Adult , Middle Aged , Male , Bortezomib , Rituximab , Retrospective Studies , Purpura, Thrombocytopenic, Idiopathic/therapy , Adrenal Cortex Hormones , Plasma Exchange , ADAMTS13 Protein
3.
J Pediatr ; 251: 187-189, 2022 12.
Article in English | MEDLINE | ID: mdl-35944718

ABSTRACT

In this retrospective single-institution cohort study of 113 hospitalized pediatric patients with respiratory coronavirus disease 2019, those admitted to the intensive care unit or requiring mechanical ventilation had significantly higher immature platelet fractions than those who did not require intensive care unit-level care or ventilation. Immature platelet fraction may be an accessible biomarker for disease severity in pediatric respiratory coronavirus disease 2019.


Subject(s)
COVID-19 , Humans , Child , COVID-19/diagnosis , SARS-CoV-2 , Retrospective Studies , Cohort Studies , Severity of Illness Index , Respiration, Artificial , Intensive Care Units , Biomarkers
5.
Curr Protoc ; 1(12): e316, 2021 Dec.
Article in English | MEDLINE | ID: mdl-34919348

ABSTRACT

Human artificial chromosomes (HACs) are gene delivery vectors that have been used for decades for gene functional studies. HACs have several advantages over viral-based gene transfer systems, including stable episomal maintenance in a single copy in the cell and the ability to carry up to megabase-sized genomic DNA segments. We have previously developed the alphoidtetO -HAC, which has a single gene acceptor loxP site that allows insertion of an individual gene of interest using Chinese hamster ovary (CHO) hybrid cells. The HAC, along with a DNA segment of interest, can then be transferred from donor CHO cells to various recipient cells of interest via microcell-mediated chromosome transfer (MMCT). Here, we detail a protocol for loading multiple genomic DNA segments or genes into the alphoidtetO -HAC vector using an iterative integration system (IIS) that utilizes recombinases Cre, ΦC31, and ΦBT. This IIS-alphoidtetO -HAC can be used for either serially assembling genomic loci or fragments of a large gene, or for inserting multiple genes into the same artificial chromosome. The insertions are executed iteratively, whereby each round results in the insertion of a new DNA segment of interest. This is accompanied by changes of expression of marker fluorescent proteins, which simplifies screening of correct clones, and changes of selection and counterselection markers, which constitutes an error-proofing mechanism that removes mis-incorporated DNA segments. In addition, the IIS-alphoidtetO -HAC carrying the genes can be eliminated from the cells, offering the possibility to compare the phenotypes of human cells with and without functional copies of the genes of interest. The resulting HAC molecules may be used to investigate biomedically relevant pathways or the regulation of multiple genes, and to potentially engineer synthetic chromosomes with a specific set of genes of interest. The IIS-alphoidtetO -HAC system is expected to be beneficial in creating multiple-gene humanized models with the purpose of understanding complex multi-gene genetic disorders. Published 2021. This article is a U.S. Government work and is in the public domain in the USA. Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Integration of the first DNA segment of interest into the IIS-alphoidteto -HAC Basic Protocol 2: Integration of a second DNA segment of interest into the IIS-alphoidteto -HAC Basic Protocol 3: Integration of a third DNA segment of interest into the IIS-alphoidteto -HAC Support Protocol: Fluorescence in situ hybridization analysis for the circular IIS-alphoidtetO -HAC.


Subject(s)
Chromosomes, Artificial, Human , Animals , CHO Cells , Chromosomes, Artificial, Human/genetics , Cricetinae , Cricetulus , DNA/genetics , Genomics , Humans , In Situ Hybridization, Fluorescence
7.
Cureus ; 13(1): e12655, 2021 Jan 12.
Article in English | MEDLINE | ID: mdl-33585140

ABSTRACT

An 18-year-old female presented with left eye periorbital swelling, erythema, and pain for three days. Computed tomographic images showed swelling of the medial rectus muscle, and she was diagnosed with orbital cellulitis and initiated on empiric antibiotics. Over the next 48 hours, she did not clinically improve, resulting in an MRI and further workup of infectious, oncologic, endocrinologic, and rheumatologic etiologies was unrevealing and ruled-out malignancy, sarcoidosis, Wegner's, and thyroid eye disease. Given the negative workup, the presentation was determined to be consistent with idiopathic orbital inflammation (orbital myositis variant) via a diagnosis of exclusion. Therefore, the patient was empirically treated with intravenous steroids that produced pronounced improvement within 24 hours. The patient was discharged in improved condition with a prednisone taper and rheumatology follow-up. Idiopathic orbital inflammation is a rare diagnosis of exclusion in pediatrics that merits prompt consideration and work-up if treatment for orbital cellulitis does not progress as expected.

8.
Oral Oncol ; 114: 105137, 2021 03.
Article in English | MEDLINE | ID: mdl-33422859

ABSTRACT

BACKGROUND: The AJCC 8th edition issued a dedicated staging system for head and neck soft tissue sarcomas (HN-STS) with 2 and 4 cm tumor cut-off points, as well as a T4 classification based on invasion of adjacent structures. Stage groupings were not provided due to a paucity of data. METHODS: We identified HN-STS patients undergoing primary surgery without neoadjuvant therapy patients in the Surveillance, Epidemiology, and End Results (SEER) database. We used multivariable analysis to examine adverse prognosticators. Then, using, recursive partitioning analysis (RPA), we established a stage grouping system that was externally validated in the National Cancer Database (NCDB). RESULTS: Multivariable analysis in the SEER cohort (N = 546) demonstrated worsened survival with tumors invading adjacent structures (P < 0.001) and increasing de-differentiation (P < 0.001). There was no prognostic difference based on size for T1-3 tumors; however, when assessed as a continuous variable, a 5 cm tumor size cut-off point was predictive of outcome. RPA generated a stage grouping system with the following five-year overall survival: RPA Stage I (pT1-3N0-1G1-2M0) 71.2%, RPA Stage II (pT4abN0-1G1-2M0/pT1-3N0-1G3-4M0) 53.4%, and RPA Stage III (pT4abN0-1G3-4M0) 17.5%. This was successfully externally validated in the NCDB cohort (P < 0.001). CONCLUSIONS: We confirm the importance of structural invasion and grade and demonstrate that the currently used size cut-off points are not prognostic. We propose a novel stage grouping system. A 5 cm tumor size cut-off point for tumor stage should be further evaluated.


Subject(s)
Head and Neck Neoplasms/diagnosis , Sarcoma/diagnosis , Adult , Aged , Female , Head and Neck Neoplasms/pathology , Humans , Male , Middle Aged , Neoplasm Staging , Prognosis , Sarcoma/pathology
9.
Cancer ; 125(17): 2975-2983, 2019 09 01.
Article in English | MEDLINE | ID: mdl-31090934

ABSTRACT

BACKGROUND: The eighth edition of the AJCC Cancer Staging Manual (AJCC 8) incorporates depth of invasion (DOI) into the pathologic tumor (pT) classification and pathologic extranodal extension (pENE) into the pathologic nodal (pN) classification for oral cavity squamous cell carcinoma (OCSCC). This study evaluated the incidence and prognostic importance of stage migration as a result of these changes in the AJCC 8 staging system. METHODS: From the National Cancer Database, cohorts were identified from patients with OCSCC undergoing definitive surgery between 2004 and 2013 for pT (n = 7184), pN (n = 13,627), and pathologic stage (pStage) analysis (n = 5580). RESULTS: DOI and pENE were prognostic in all groups except for pN3 according to the seventh edition of the AJCC Cancer Staging Manual (AJCC 7). Upstaging was seen in 12.4% of patients for the pT classification, in 13.3% for the pN classification, and in 24.8% for the overall pStage grouping. Notably, upstaging led to similar or improved 5-year overall survival (OS) for every AJCC 8 pT/N classification except pStage IVB. Patients with AJCC 7 pT1 tumors that were upstaged to AJCC 8 pT3 tumors had improved OS in comparison with the remainder of the pT3 group (71.7% vs 43.7%; P < .0001). A multivariable analysis of upstaged pT3N0 patients demonstrated a reduced risk of death with the receipt of postoperative radiotherapy (PORT; hazard ratio, 0.56; 95% confidence interval, 0.33-0.95; P = .03). CONCLUSIONS: Upstaging is common in AJCC 8, and patients with upstaged tumors demonstrate improved survival; these factors should be kept in mind when one is interpreting data with the new staging system. PORT may reduce deaths among newly upstaged pT3N0 patients, and further study is needed in this area.


Subject(s)
Carcinoma, Squamous Cell/mortality , Carcinoma, Squamous Cell/pathology , Mouth Neoplasms/mortality , Mouth Neoplasms/pathology , Aged , Cell Movement , Female , Humans , Male , Middle Aged , Multivariate Analysis , Neoplasm Staging , Prognosis , Proportional Hazards Models , Survival Analysis
10.
Cancer ; 125(12): 2018-2026, 2019 06 15.
Article in English | MEDLINE | ID: mdl-30748002

ABSTRACT

BACKGROUND: Treatment at high-volume surgical facilities (HVSFs) provides a survival benefit for patients with head and neck squamous cell carcinomas (HNSCCs); however, it is unknown what role postoperative radiation therapy (PORT) plays in achieving the improved outcomes. METHODS: From the National Cancer Database, 6844 patients with locally advanced invasive HNSCCs of the oral cavity, oropharynx, larynx, and hypopharynx who underwent definitive surgery with PORT between 2004 and 2013 were identified. HVSFs were those in the top percentile for annual case volume during this period. RESULTS: The median follow-up was 54 months. Compared with a lower volume surgical facility (LVSF), an HVSF improved 5-year overall survival (OS; 57.7% at HVSFs vs 52.5% at LVSFs; P = .0003). Overall, 31.6% of the patients changed their radiation therapy (RT) facility after surgery, with this being more common at HVSFs (39.1% vs 28.9% at LVSFs; P < .001). Among those patients undergoing surgery at an HVSF, remaining at the same facility for RT improved 5-year OS (63.1% vs 49.3% with a facility change; P < .0001). A propensity score-matched cohort of patients treated at HVSFs confirmed the improved 5-year OS when patients remained at the treating HVSF for RT (59.2% vs 50.7% with a facility change; P = .005). In a multivariate analysis, treatment at an HVSF and remaining there for RT resulted in a reduced hazard of death (hazard ratio, 0.81; 95% confidence interval, 0.69-0.94; P = .006). CONCLUSIONS: The survival benefit associated with HVSFs persists only when patients remain at the facility for RT, and this suggests that facility specialization and/or high-volume PORT may assist in driving the OS improvement.


Subject(s)
Head and Neck Neoplasms/mortality , Radiotherapy, Adjuvant/mortality , Squamous Cell Carcinoma of Head and Neck/mortality , Databases, Factual , Female , Follow-Up Studies , Head and Neck Neoplasms/pathology , Head and Neck Neoplasms/radiotherapy , Humans , Male , Middle Aged , Neoplasm Invasiveness , Postoperative Care , Prognosis , Squamous Cell Carcinoma of Head and Neck/pathology , Squamous Cell Carcinoma of Head and Neck/radiotherapy , Survival Rate
11.
Oral Oncol ; 85: 35-39, 2018 10.
Article in English | MEDLINE | ID: mdl-30220317

ABSTRACT

BACKGROUND: The 8th edition American Joint Committee on Cancer staging system for resected HPV-positive oropharynx carcinoma (HPV+ OPC) highlights high node number as a critical determinant of survival. We sought to characterize outcomes and patterns of failure in patients with high pathologically involved node number oropharynx cancer. METHODS: We retrospectively identified 116 HPV+ OPC patients sequentially treated with neck dissection and either resection or intraoperative brachytherapy of the primary tumor between 2010 and 2016. External beam radiation was given based on the pathologic findings. Cox proportional hazards regression was used for multivariate analysis. RESULTS: With a median follow-up of 27 months, the 3-year overall survival and progression free survival (PFS) were 89% and 81%, respectively. On multivariate analysis, ≥5 involved lymph nodes was significantly associated with worse PFS (hazard ratio 4.3, 95% confidence interval (CI) 1.5-12.0, P = 0.001). Rates of 3-year locoregional recurrence (LRR) in patients with ≤4 vs ≥5 were 6% and 22% (log-rank P = 0.12). Rates of 3-year distant metastases (DM) were 12% and 53% between ≤4 and ≥5 (log-rank P < 0.001). CONCLUSION: Our findings confirm that patients with 5 or more involved lymph nodes appear to have substantially worsened rates of disease recurrence. While these patients appear to be at high risk of both LRR and DM, the predominant mechanism of failure is distant, and the rate of DM in this group was over 50%. Dedicated clinical trials in this patient population are warranted with a focus on mitigating the high DM rate.


Subject(s)
Carcinoma, Squamous Cell/secondary , Lymphatic Metastasis , Oropharyngeal Neoplasms/pathology , Papillomavirus Infections/pathology , Adult , Aged , Aged, 80 and over , Brachytherapy , Carcinoma, Squamous Cell/radiotherapy , Carcinoma, Squamous Cell/surgery , Combined Modality Therapy , Female , Follow-Up Studies , Humans , Male , Middle Aged , Neck Dissection , Neoplasm Metastasis , Neoplasm Recurrence, Local/epidemiology , Neoplasm Recurrence, Local/pathology , Oropharyngeal Neoplasms/radiotherapy , Oropharyngeal Neoplasms/surgery , Papillomavirus Infections/radiotherapy , Papillomavirus Infections/surgery , Progression-Free Survival , Proportional Hazards Models , Radiotherapy, Adjuvant , Retrospective Studies , Salvage Therapy
12.
Pract Radiat Oncol ; 8(6): 397-403, 2018.
Article in English | MEDLINE | ID: mdl-29730282

ABSTRACT

PURPOSE: Initial deescalation studies for human papilloma virus (HPV)-positive driven oropharyngeal squamous cell carcinomas (HPV+ OPSCC) altered radiation therapy dose or the systemic agent used. Newer trials examine the disease control achieved with a reduced elective nodal field. We examined patterns of nodal involvement in patients with HPV+ OPSCC with a focus on implications for radiation field design for treatment deescalation. METHODS AND MATERIALS: Records of patients with HPV+ OPSCC with preoperative imaging (computed tomography or fludeoxyglucose positron emission tomography/computed tomography) who underwent neck dissection without neoadjuvant therapy from 2010 to 2017 were retrospectively reviewed. The number and location of clinically positive lymph nodes on preoperative imaging were compared with those documented on pathology. These data were then used to establish the probability of missing nodal disease in 3 modified radiation field designs. RESULTS: One hundred patients were included. The median time between imaging and surgery was 22 days. The most common clinical N stage was cN2a (35%), whereas the most common pathologic N stage was pN2b (45%). The median number of radiographically and pathologically involved nodes was 1 (range, 0-6) and 2 (range, 0-11), respectively. Forty-three percent of patients had more pathologically involved nodes than predicted on imaging, whereas 21% had pathologic involvement at an additional nodal level not predicted on imaging. Of the 21 patients with additional pathologically involved nodal levels, 14 had involvement of a directly adjacent station, 4 were patients with a cN0 hemineck with pathologically positive level II disease, and 3 had pathologic involvement of level 2 echelons removed from that predicted on imaging. CONCLUSION: Our study suggests that radiation fields encompassing only clinically involved nodes or levels has an unacceptably high likelihood of missing subclinical disease. Alternatively, treating the first uninvolved echelon nodes in addition would cover pathologic sites of disease in 97% of patients. This approach merits further study in prospective trials.


Subject(s)
Carcinoma, Squamous Cell/secondary , Image Processing, Computer-Assisted/methods , Oropharyngeal Neoplasms/pathology , Papillomavirus Infections/pathology , Positron Emission Tomography Computed Tomography/methods , Radiotherapy Planning, Computer-Assisted/methods , Adult , Aged , Aged, 80 and over , Carcinoma, Squamous Cell/diagnostic imaging , Carcinoma, Squamous Cell/virology , Female , Follow-Up Studies , Humans , Lymphatic Metastasis , Male , Middle Aged , Neoplasm Staging , Oropharyngeal Neoplasms/diagnostic imaging , Oropharyngeal Neoplasms/virology , Papillomaviridae , Papillomavirus Infections/diagnostic imaging , Papillomavirus Infections/virology , Prognosis , Radiotherapy Dosage , Radiotherapy, Intensity-Modulated/methods , Retrospective Studies
13.
Oncotarget ; 9(20): 15275-15291, 2018 Mar 16.
Article in English | MEDLINE | ID: mdl-29632643

ABSTRACT

Tandem segmental duplications (SDs) greater than 10 kb are widespread in complex genomes. They provide material for gene divergence and evolutionary adaptation, while formation of specific de novo SDs is a hallmark of cancer and some human diseases. Most SDs map to distinct genomic regions termed 'duplication blocks'. SDs organization within these blocks is often poorly characterized as they are mosaics of ancestral duplicons juxtaposed with younger duplicons arising from more recent duplication events. Structural and functional analysis of SDs is further hampered as long repetitive DNA structures are underrepresented in existing BAC and YAC libraries. We applied Transformation-Associated Recombination (TAR) cloning, a versatile technique for large DNA manipulation, to selectively isolate the coronary artery disease (CAD) interval sequence within the 9p21.3 chromosome locus from a patient with coronary artery disease and normal individuals. Four tandem head-to-tail duplicons, each ∼50 kb long, were recovered in the patient but not in normal individuals. Sequence analysis revealed that the repeats varied by 10-15 SNPs between each other and by 82 SNPs between the human genome sequence (version hg19). SNPs polymorphism within the junctions between repeats allowed two junction types to be distinguished, Type 1 and Type 2, which were found at a 2:1 ratio. The junction sequences contained an Alu element, a sequence previously shown to play a role in duplication. Knowledge of structural variation in the CAD interval from more patients could help link this locus to cardiovascular diseases susceptibility, and maybe relevant to other cases of regional amplification, including cancer.

14.
ACS Synth Biol ; 7(1): 63-74, 2018 01 19.
Article in English | MEDLINE | ID: mdl-28799737

ABSTRACT

The production of cells capable of carrying multiple transgenes to Mb-size genomic loci has multiple applications in biomedicine and biotechnology. In order to achieve this goal, three key steps are required: (i) cloning of large genomic segments; (ii) insertion of multiple DNA blocks at a precise location and (iii) the capability to eliminate the assembled region from cells. In this study, we designed the iterative integration system (IIS) that utilizes recombinases Cre, ΦC31 and ΦBT1, and combined it with a human artificial chromosome (HAC) possessing a regulated kinetochore (alphoidtetO-HAC). We have demonstrated that the IIS-alphoidtetO-HAC system is a valuable genetic tool by reassembling a functional gene from multiple segments on the HAC. IIS-alphoidtetO-HAC has several notable advantages over other artificial chromosome-based systems. This includes the potential to assemble an unlimited number of genomic DNA segments; a DNA assembly process that leaves only a small insertion (<60 bp) scar between adjacent DNA, allowing genes reassembled from segments to be spliced correctly; a marker exchange system that also changes cell color, and counter-selection markers at each DNA insertion step, simplifying selection of correct clones; and presence of an error proofing mechanism to remove cells with misincorporated DNA segments, which improves the integrity of assembly. In addition, the IIS-alphoidtetO-HAC carrying a locus of interest is removable, offering the unique possibility to revert the cell line to its pretransformed state and compare the phenotypes of human cells with and without a functional copy of a gene(s). Thus, IIS-alphoidtetO-HAC allows investigation of complex biomedical pathways, gene(s) regulation, and has the potential to engineer synthetic chromosomes with a predetermined set of genes.


Subject(s)
Chromosomes, Artificial, Human/genetics , DNA/metabolism , Integrases/genetics , Kinetochores/metabolism , Animals , CHO Cells , Cricetinae , Cricetulus , DNA/genetics , Humans , In Situ Hybridization, Fluorescence , Integrases/metabolism , Plasmids/genetics , Plasmids/metabolism , Recombination, Genetic , Von Hippel-Lindau Tumor Suppressor Protein/genetics
15.
Pract Radiat Oncol ; 7(5): e317-e321, 2017.
Article in English | MEDLINE | ID: mdl-28356201

ABSTRACT

PURPOSE: Xerostomia remains a common side effect of head and neck irradiation. Conflicting data exist regarding the likelihood of level IB involvement for patients with oropharyngeal squamous cell cancer (OPSCC), and data are limited on this risk in patients with human papillomavirus-positive disease. This study examined surgically treated OPSCC to determine the risk of pathologic level IB nodal involvement and to identify a cohort of patients in whom ipsilateral level IB radiation therapy may be safely omitted. METHODS AND MATERIALS: A total of 102 submandibular nodal dissections were identified (92 ipsilateral and 10 contralateral) in 92 patients from 2010 to 2016 in those undergoing primary surgical treatment and dissection of ipsilateral level IB lymph nodes. Radiographically positive cases were excluded. Retrospective chart review was used for data collection, and the rate of pathologic level IB involvement was determined. RESULTS: The ipsilateral level IB nodal station had negative imaging and pathologically positive nodes at rates of 4.3% in OPSCC and 5.3% in human papillomavirus-positive OPSCC. Positive node burden in the ipsilateral neck at stations other than IB appeared to correlate with the risk of pathologic positive IB (pIB+) nodes: 50% of pathologically IB-negative patients had 2 or more positive nodes versus 75% of pIB+ patients who had 4 or more positive nodes. CONCLUSIONS: Our data indicate a low risk of pathologic level IB involvement in early-stage OPSCC. High positive node burden in stations near level IB may be associated with a higher chance of pathologic level IB involvement.


Subject(s)
Carcinoma, Squamous Cell/therapy , Head and Neck Neoplasms/therapy , Lymph Nodes/pathology , Organ Sparing Treatments/methods , Oropharyngeal Neoplasms/therapy , Submandibular Gland/radiation effects , Xerostomia/prevention & control , Carcinoma, Squamous Cell/pathology , Carcinoma, Squamous Cell/virology , Female , Head and Neck Neoplasms/pathology , Head and Neck Neoplasms/virology , Humans , Lymph Node Excision , Lymph Nodes/surgery , Lymphatic Metastasis , Male , Middle Aged , Neoplasm Staging , Oropharyngeal Neoplasms/pathology , Oropharyngeal Neoplasms/virology , Papillomaviridae/isolation & purification , Parotid Gland/radiation effects , Radiotherapy, Adjuvant/adverse effects , Radiotherapy, Adjuvant/methods , Retrospective Studies , Squamous Cell Carcinoma of Head and Neck , Xerostomia/etiology
16.
Oncotarget ; 7(12): 14841-56, 2016 Mar 22.
Article in English | MEDLINE | ID: mdl-26943579

ABSTRACT

Accumulating data indicates that chromosome instability (CIN) common to cancer cells can be used as a target for cancer therapy. At present the rate of chromosome mis-segregation is quantified by laborious techniques such as coupling clonal cell analysis with karyotyping or fluorescence in situ hybridization (FISH). Recently, a novel assay was developed based on the loss of a non-essential human artificial chromosome (HAC) carrying a constitutively expressed EGFP transgene ("loss of signal" assay). Using this system, anticancer drugs can be easily ranked on by their effect on HAC loss. However, it is problematic to covert this "loss of signal" assay into a high-throughput screen to identify drugs and mutations that increase CIN levels. To address this point, we re-designed the HAC-based assay. In this new system, the HAC carries a constitutively expressed shRNA against the EGFP transgene integrated into human genome. Thus, cells that inherit the HAC display no green fluorescence, while cells lacking the HAC do. We verified the accuracy of this "gain of signal" assay by measuring the level of CIN induced by known antimitotic drugs and added to the list of previously ranked CIN inducing compounds, two newly characterized inhibitors of the centromere-associated protein CENP-E, PF-2771 and GSK923295 that exhibit the highest effect on chromosome instability measured to date. The "gain of signal" assay was also sensitive enough to detect increase of CIN after siRNA depletion of known genes controlling mitotic progression through distinct mechanisms. Hence this assay can be utilized in future experiments to uncover novel human CIN genes, which will provide novel insight into the pathogenesis of cancer. Also described is the possible conversion of this new assay into a high-throughput screen using a fluorescence microplate reader to characterize chemical libraries and identify new conditions that modulate CIN level.


Subject(s)
Biological Assay/methods , Chromosomal Instability , Chromosomes, Artificial, Human/genetics , Fibrosarcoma/diagnosis , Fibrosarcoma/genetics , Green Fluorescent Proteins/metabolism , Apoptosis , Cell Proliferation , Green Fluorescent Proteins/genetics , Humans , In Situ Hybridization, Fluorescence , Tumor Cells, Cultured
17.
Cancer Res ; 76(4): 902-11, 2016 Feb 15.
Article in English | MEDLINE | ID: mdl-26837770

ABSTRACT

Whole chromosomal instability (CIN), manifested as unequal chromosome distribution during cell division, is a distinguishing feature of most cancer types. CIN is generally considered to drive tumorigenesis, but a threshold level exists whereby further increases in CIN frequency in fact hinder tumor growth. While this attribute is appealing for therapeutic exploitation, drugs that increase CIN beyond this therapeutic threshold are currently limited. In our previous work, we developed a quantitative assay for measuring CIN based on the use of a nonessential human artificial chromosome (HAC) carrying a constitutively expressed EGFP transgene. Here, we used this assay to rank 62 different anticancer drugs with respect to their effects on chromosome transmission fidelity. Drugs with various mechanisms of action, such as antimicrotubule activity, histone deacetylase inhibition, mitotic checkpoint inhibition, and targeting of DNA replication and damage responses, were included in the analysis. Ranking of the drugs based on their ability to induce HAC loss revealed that paclitaxel, gemcitabine, dactylolide, LMP400, talazoparib, olaparib, peloruside A, GW843682, VX-680, and cisplatin were the top 10 drugs demonstrating HAC loss at a high frequency. Therefore, identification of currently used compounds that greatly increase chromosome mis-segregation rates should expedite the development of new therapeutic strategies to target and leverage the CIN phenotype in cancer cells.


Subject(s)
Cell Transformation, Neoplastic/genetics , Chromosomal Instability/genetics , Cell Line, Tumor , Genes, Tumor Suppressor , Humans , Transgenes
18.
Nucleic Acids Res ; 43(9): e57, 2015 May 19.
Article in English | MEDLINE | ID: mdl-25712097

ABSTRACT

Human artificial chromosome (HAC)-based vectors represent an alternative technology for gene delivery and expression with a potential to overcome the problems caused by virus-based vectors. The recently developed alphoid(tetO)-HAC has an advantage over other HAC vectors because it can be easily eliminated from cells by inactivation of the HAC kinetochore via binding of chromatin modifiers, tTA or tTS, to its centromeric tetO sequences. This provides a unique control for phenotypes induced by genes loaded into the HAC. The alphoid(tetO)-HAC elimination is highly efficient when a high level of chromatin modifiers as tetR fusion proteins is achieved following transfection of cells by a retrovirus vector. However, such vectors are potentially mutagenic and might want to be avoided under some circumstances. Here, we describe a novel system that allows verification of phenotypic changes attributed to expression of genes from the HAC without a transfection step. We demonstrated that a single copy of tTA(VP64) carrying four tandem repeats of the VP16 domain constitutively expressed from the HAC is capable to generate chromatin changes in the HAC kinetochore that are not compatible with its function. To adopt the alphoid(tetO)-HAC for routine gene function studies, we constructed a new TAR-BRV- tTA(VP64) cloning vector that allows a selective isolation of a gene of interest from genomic DNA in yeast followed by its direct transfer to bacterial cells and subsequent loading into the loxP site of the alphoid(tetO)-HAC in hamster CHO cells from where the HAC may be MMCT-transferred to the recipient human cells.


Subject(s)
Chromosomes, Artificial, Human , Genetic Vectors , Animals , CHO Cells , Cell Line, Tumor , Chromatin/metabolism , Cricetinae , Cricetulus , Gene Expression , Humans , Kinetochores/metabolism , Phenotype , Trans-Activators/genetics
19.
Nucleic Acids Res ; 43(8): e55, 2015 Apr 30.
Article in English | MEDLINE | ID: mdl-25690893

ABSTRACT

Transformation-associated recombination (TAR) protocol allowing the selective isolation of full-length genes complete with their distal enhancer regions and entire genomic loci with sizes up to 250 kb from complex genomes in yeast S. cerevisiae has been developed more than a decade ago. However, its wide spread usage has been impeded by a low efficiency (0.5-2%) of chromosomal region capture during yeast transformants which in turn requires a time-consuming screen of hundreds of colonies. Here, we demonstrate that pre-treatment of genomic DNA with CRISPR-Cas9 nucleases to generate double-strand breaks near the targeted genomic region results in a dramatic increase in the fraction of gene-positive colonies (up to 32%). As only a dozen or less yeast transformants need to be screened to obtain a clone with the desired chromosomal region, extensive experience with yeast is no longer required. A TAR-CRISPR protocol may help to create a bank of human genes, each represented by a genomic copy containing its native regulatory elements, that would lead to a significant advance in functional, structural and comparative genomics, in diagnostics, gene replacement, generation of animal models for human diseases and has a potential for gene therapy.


Subject(s)
CRISPR-Cas Systems , Cloning, Molecular/methods , Endodeoxyribonucleases/metabolism , Genes , Saccharomyces cerevisiae/genetics , Cell Cycle Proteins/genetics , Chromosomes, Fungal , Genetic Loci , Genome, Fungal , Humans , Nuclear Proteins/genetics , RNA/metabolism , Recombination, Genetic
20.
Methods Mol Biol ; 1227: 3-26, 2015.
Article in English | MEDLINE | ID: mdl-25239739

ABSTRACT

Transformation-associated recombination (TAR) cloning allows selective isolation of full-length genes and genomic loci as large circular Yeast Artificial Chromosomes (YACs) in yeast. The method has a broad application for structural and functional genomics, long-range haplotyping, characterization of chromosomal rearrangements, and evolutionary studies. In this paper, we describe a basic protocol for gene isolation by TAR as well as a method to convert TAR isolates into Bacterial Artificial Chromosomes (BACs) using a retrofitting vector. The retrofitting vector contains a 3' HPRT-loxP cassette to allow subsequent gene loading into a unique loxP site of the HAC-based (Human Artificial Chromosome) gene delivery vector. The benefit of combining the TAR gene cloning technology with the HAC gene delivery system for gene expression studies is discussed.


Subject(s)
Cloning, Molecular/methods , DNA, Fungal/genetics , Gene Expression Regulation, Fungal , Saccharomyces cerevisiae/genetics , Spheroplasts/genetics , Animals , CHO Cells , Chromosomes, Artificial, Bacterial/chemistry , Chromosomes, Artificial, Bacterial/metabolism , Chromosomes, Artificial, Human/chemistry , Chromosomes, Artificial, Human/metabolism , Chromosomes, Artificial, Yeast/chemistry , Chromosomes, Artificial, Yeast/metabolism , Cricetulus , DNA, Fungal/metabolism , Escherichia coli/genetics , Escherichia coli/metabolism , Genetic Vectors/chemistry , Genetic Vectors/metabolism , Humans , Recombination, Genetic , Saccharomyces cerevisiae/metabolism , Spheroplasts/metabolism , Transformation, Genetic
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