Paula Klurfan

Publications (2)17.46 Total impact

• Article: A Cancer Stem Cell Model for Studying Brain Metastases From Primary Lung Cancer.

  Sara M Nolte, Chitra Venugopal, Nicole McFarlane, Olena Morozova, Robin M Hallett, Erin O'Farrell, Branavan Manoranjan, Naresh K Murty, Paula Klurfan, Edward Kachur, John P Provias, Forough Farrokhyar, John A Hassell, Marco Marra, Sheila K Singh
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  ABSTRACT: Background Brain metastases are most common in adults with lung cancer, predicting uniformly poor patient outcome, with a median survival of only months. Despite their frequency and severity, very little is known about tumorigenesis in brain metastases.Methods We applied previously developed primary solid tumor-initiating cell models to the study of brain metastases from the lung to evaluate the presence of a cancer stem cell population. Patient-derived brain metastases (n = 20) and the NCI-H1915 cell line were cultured as stem-enriching tumorspheres. We used in vitro limiting-dilution and sphere-forming assays, as well as intracranial human-mouse xenograft models. To determine genes overexpressed in brain metastasis tumorspheres, we performed comparative transcriptome analysis. All statistical analyses were two-sided.ResultsPatient-derived brain metastasis tumorspheres had a mean sphere-forming capacity of 33 spheres/2000 cells (SD = 33.40) and median stem-cell frequency of 1/60 (range = 0-1/141), comparable to that of primary brain tumorspheres (P = .53 and P = .20, respectively). Brain metastases also expressed CD15 and CD133, markers suggestive of a stemlike population. Through intracranial xenotransplantation, brain metastasis tumorspheres were found to recapitulate the original patient tumor heterogeneity. We also identified several genes overexpressed in brain metastasis tumorspheres as statistically significant predictors of poor survival in primary lung cancer.Conclusions For the first time, we demonstrate the presence of a stemlike population in brain metastases from the lung. We also show that NCI-H1915 tumorspheres could be useful in studying self-renewal and tumor initiation in brain metastases. Our candidate genes may be essential to metastatic stem cell populations, where pathway interference may be able to transform a uniformly fatal disease into a more localized and treatable one.
  CancerSpectrum Knowledge Environment 02/2013; · 14.07 Impact Factor
• Article: Bmi1 marks intermediate precursors during differentiation of human brain tumor initiating cells.

  Chitra Venugopal, Na Li, Xin Wang, Branavan Manoranjan, Cynthia Hawkins, Thorsteinn Gunnarsson, Robert Hollenberg, Paula Klurfan, Naresh Murty, Jacek Kwiecien, Forough Farrokhyar, John P Provias, Christopher Wynder, Sheila K Singh
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  ABSTRACT: The master regulatory gene Bmi1 modulates key stem cell properties in neural precursor cells (NPCs), and has been implicated in brain tumorigenesis. We previously identified a population of CD133+ brain tumor cells possessing stem cell properties, known as brain tumor initiating cells (BTICs). Here, we characterize the expression and role of Bmi1 in primary minimally cultured human glioblastoma (GBM) patient isolates in CD133+ and CD133- sorted populations. We find that Bmi1 expression is increased in CD133- cells, and Bmi1 protein and transcript expression are highest during intermediate stages of differentiation as CD133+ BTICs lose their CD133 expression. Furthermore, in vitro stem cell assays and Bmi1 knockdown show that Bmi1 contributes to self-renewal in CD133+ populations, but regulates proliferation and cell fate determination in CD133- populations. Finally, we test if our in vitro stem cell assays and Bmi1 expression in BTIC patient isolates are predictive of clinical outcome for GBM patients. Bmi1 expression profiles show a marked elevation in the proneural GBM subtype, and stem cell frequency as assessed by tumor sphere assays correlates with patient outcome.
  Stem cell research 03/2012; 8(2):141-53. · 3.39 Impact Factor