Publications by authors named "Samuel Sprowls"

8 Publications

  • Page 1 of 1

Irradiator Commissioning and Dosimetry for Assessment of LQ α and β Parameters, Radiation Dosing Schema, and in vivo Dose Deposition.

J Vis Exp 2021 03 11(169). Epub 2021 Mar 11.

Department of Basic Pharmaceutical Sciences, School of Pharmacy, West Virginia University;

Radiation dosimetry is critical in the accurate delivery and reproducibility of radiation schemes in preclinical models for high translational relevance. Prior to performing any in vitro or in vivo experiments, the specific dose output for the irradiator and individual experimental designs must be assessed. Using an ionization chamber, electrometer, and solid water setup, the dose output of wide fields at isocenter can be determined. Using a similar setup with radiochromic films in the place of the ionization chamber, dose rates for smaller fields at different depths can also be determined. In vitro clonogenic survival assays of cancer cells in response to radiation treatment are inexpensive experiments that provide a measure of inherent radio-sensitivity of cell lines by fitting these data with the traditional linear-quadratic model. Model parameters estimated from these assays, combined with the principles of biologic effective doses, allows one to develop varying fractionation schedules for radiation treatment that provide equivalent effective doses in tumor-bearing animal experiments. This is an important factor to consider and correct for in comparing in vivo radiation therapy schedules to eliminate potential confounding of results due to variance in the delivered effective doses. Taken together, this article provides a general method for dose output verification preclinical animal and cabinet irradiators, in vitro assessment of radio-sensitivity, and verification of radiation delivery in small living organisms.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3791/61692DOI Listing
March 2021

Y Chromosome LncRNA Are Involved in Radiation Response of Male Non-Small Cell Lung Cancer Cells.

Cancer Res 2020 10 2;80(19):4046-4057. Epub 2020 Jul 2.

Department of Microbiology, Immunology & Cell Biology, West Virginia University Cancer Institute, School of Medicine, West Virginia University, Morgantown, West Virginia.

Numerous studies have implicated changes in the Y chromosome in male cancers, yet few have investigated the biological importance of Y chromosome noncoding RNA. Here we identify a group of Y chromosome-expressed long noncoding RNA (lncRNA) that are involved in male non-small cell lung cancer (NSCLC) radiation sensitivity. Radiosensitive male NSCLC cell lines demonstrated a dose-dependent induction of following irradiation, which was not observed in radioresistant male NSCLC cell lines. Cytogenetics revealed the loss of chromosome Y (LOY) in the radioresistant male NSCLC cell lines. Gain- and loss-of-function experiments indicated that transcripts affect cell viability and apoptosis. Computational prediction of RNA binding proteins (RBP) motifs and UV-cross-linking and immunoprecipitation (CLIP) assays identified IGF2BP3, an RBP involved in mRNA stability, as a binding partner for RNA. The presence of reduced the half-life of known IGF2BP3 binding mRNA, such as the antiapoptotic mRNA, as well as the oncogenic mRNA. Assessment of Y chromosome in NSCLC tissue microarrays and expression of in NSCLC RNA-seq and microarray data revealed a negative correlation between the loss of the Y chromosome or and overall survival. Thus, expression and LOY could represent an important marker of radiotherapy in NSCLC. SIGNIFICANCE: This study describes previously unknown Y chromosome-expressed lncRNA regulators of radiation response in male NSCLC and show a correlation between loss of chromosome Y and radioresistance. GRAPHICAL ABSTRACT: http://cancerres.aacrjournals.org/content/canres/80/19/4046/F1.large.jpg.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1158/0008-5472.CAN-19-4032DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7541653PMC
October 2020

Hypomethylating Agent Azacitidine Is Effective in Treating Brain Metastasis Triple-Negative Breast Cancer Through Regulation of DNA Methylation of Keratin 18 Gene.

Transl Oncol 2020 Jun 11;13(6):100775. Epub 2020 May 11.

Department of Biomedical Sciences, West Virginia School of Osteopathic Medicine, 400 Lee Street North, Lewisburg, WV. Electronic address:

Breast cancer patients presenting with symptomatic brain metastases have poor prognosis, and current chemotherapeutic agents are largely ineffective. In this study, we evaluated the hypomethylating agent azacitidine (AZA) for its potential as a novel therapeutic in preclinical models of brain metastasis of breast cancer. We used the parental triple-negative breast cancer MDA-MB-231 (231) cells and their brain colonizing counterpart (231Br) to ascertain phenotypic differences in response to AZA. We observed that 231Br cells have higher metastatic potential compared to 231 cells. With regard to therapeutic value, the AZA IC value in 231Br cells is significantly lower than that in parental cells (P < .01). AZA treatment increased apoptosis and inhibited the Wnt signaling transduction pathway, angiogenesis, and cell metastatic capacity to a significantly higher extent in the 231Br line. AZA treatment in mice with experimental brain metastases significantly reduced tumor burden (P = .0112) and increased survival (P = .0026) compared to vehicle. Lastly, we observed a decreased expression of keratin 18 (an epithelial maker) in 231Br cells due to hypermethylation, elucidating a potential mechanism of action of AZA in treating brain metastases from breast cancer.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.tranon.2020.100775DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7225776PMC
June 2020

Drug resistance occurred in a newly characterized preclinical model of lung cancer brain metastasis.

BMC Cancer 2020 Apr 7;20(1):292. Epub 2020 Apr 7.

Department of Basic Pharmaceutical Sciences, School of Pharmacy, West Virginia University, 108 Biomedical Drive, Morgantown, WV, 26506, USA.

Background: Cancer metastasis and drug resistance have traditionally been studied separately, though these two lethal pathological phenomena almost always occur concurrently. Brain metastasis occurs in a large proportion of lung cancer patients (~ 30%). Once diagnosed, patients have a poor prognosis surviving typically less than 1 year due to lack of treatment efficacy.

Methods: Human metastatic lung cancer cells (PC-9-Br) were injected into the left cardiac ventricle of female athymic nude mice. Brain lesions were allowed to grow for 21 days, animals were then randomized into treatment groups and treated until presentation of neurological symptoms or when moribund. Prior to tissue collection mice were injected with Oregon Green and C-Aminoisobutyric acid followed by an indocyanine green vascular washout. Tracer accumulation was determined by quantitative fluorescent microscopy and quantitative autoradiography. Survival was tracked and tumor burden was monitored via bioluminescent imaging. Extent of mutation differences and acquired resistance was measured in-vitro through half-maximal inhibitory assays and qRT-PCR analysis.

Results: A PC-9 brain seeking line (PC-9-Br) was established. Mice inoculated with PC-9-Br resulted in a decreased survival time compared with mice inoculated with parental PC-9. Non-targeted chemotherapy with cisplatin and etoposide (51.5 days) significantly prolonged survival of PC-9-Br brain metastases in mice compared to vehicle control (42 days) or cisplatin and pemetrexed (45 days). Further in-vivo imaging showed greater tumor vasculature in mice treated with cisplatin and etoposide compared to non-tumor regions, which was not observed in mice treated with vehicle or cisplatin and pemetrexed. More importantly, PC-9-Br showed significant resistance to gefitinib by in-vitro MTT assays (IC50 > 2.5 μM at 48 h and 0.1 μM at 72 h) compared with parental PC-9 (IC50: 0.75 μM at 48 h and 0.027 μM at 72 h). Further studies on the molecular mechanisms of gefitinib resistance revealed that EGFR and phospho-EGFR were significantly decreased in PC-9-Br compared with PC-9. Expression of E-cadherin and vimentin did not show EMT in PC-9-Br compared with parental PC-9, and PC-9-Br had neither a T790M mutation nor amplifications of MET and HER2 compared with parental PC-9.

Conclusion: Our study demonstrated that brain metastases of lung cancer cells may independently prompt drug resistance without drug treatment.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s12885-020-06808-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7137432PMC
April 2020

MiR-34a Interacts with Cytochrome c and Shapes Stroke Outcomes.

Sci Rep 2020 02 24;10(1):3233. Epub 2020 Feb 24.

Neuroscience, Center for Basic and Translational Stroke Research; West Virginia University, Morgantown, West Virginia, 26506, USA.

Blood-brain barrier (BBB) dysfunction occurs in cerebrovascular diseases and neurodegenerative disorders such as stroke. Opening of the BBB during a stroke has a negative impact on acute outcomes. We have recently demonstrated that miR-34a regulates the BBB by targeting cytochrome c (CYC) in vitro. To investigate the role of miR-34a in a stroke, we purified primary cerebrovascular endothelial cells (pCECs) from mouse brains following 1 h transient middle cerebral artery occlusion (tMCAO) and measured real-time PCR to detect miR-34a levels. We demonstrate that the miR-34a levels are elevated in pCECs from tMCAO mice at the time point of BBB opening following 1 h tMCAO and reperfusion. Interestingly, knockout of miR-34a significantly reduces BBB permeability, alleviates disruption of tight junctions, and improves stroke outcomes compared to wild-type (WT) controls. CYC is decreased in the ischemic hemispheres and pCECs from WT but not in miR-34a mice following stroke reperfusion. We further confirmed CYC is a target of miR-34a by a dural luciferase reporter gene assay in vitro. Our study provides the first description of miR-34a affecting stroke outcomes and may lead to discovery of new mechanisms and treatments for cerebrovascular and neurodegenerative diseases such as stroke.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41598-020-59997-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7040038PMC
February 2020

Improving CNS Delivery to Brain Metastases by Blood-Tumor Barrier Disruption.

Trends Cancer 2019 08 20;5(8):495-505. Epub 2019 Jul 20.

Department of Pharmaceutical Sciences, School of Pharmacy, West Virginia University HSC, Morgantown, West Virginia 26506, USA. Electronic address:

Brain metastases encompass nearly 80% of all intracranial tumors. A late stage diagnosis confers a poor prognosis, with patients typically surviving less than 2 years. Poor survival can be equated to limited effective treatment modalities. One reason for the failure rates is the presence of the blood-brain barrier (BBB) and blood-tumor barrier (BTB) that limit the access of potentially effective chemotherapeutics to metastatic lesions. Strategies to overcome these barriers include new small molecule entities capable of crossing into the brain parenchyma, novel formulations of existing chemotherapies, and disruptive techniques. Here, we review BBB physiology and BTB pathophysiology. Additionally, we review the limitations of routinely practiced therapies and three current methods being explored for BBB/BTB disruption for improved delivery of chemotherapy to brain tumors.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.trecan.2019.06.003DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6703178PMC
August 2019

Development of a Cx46 Targeting Strategy for Cancer Stem Cells.

Cell Rep 2019 04;27(4):1062-1072.e5

Department of Cellular and Molecular Medicine, Lerner Research Institute, Cleveland Clinic, Cleveland, OH 44195, USA; Department of Molecular Medicine, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH 44195, USA; Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, OH 44106, USA. Electronic address:

Gap-junction-mediated cell-cell communication enables tumor cells to synchronize complex processes. We previously found that glioblastoma cancer stem cells (CSCs) express higher levels of the gap junction protein Cx46 compared to non-stem tumor cells (non-CSCs) and that this was necessary and sufficient for CSC maintenance. To understand the mechanism underlying this requirement, we use point mutants to disrupt specific functions of Cx46 and find that Cx46-mediated gap-junction coupling is critical for CSCs. To develop a Cx46 targeting strategy, we screen a clinically relevant small molecule library and identify clofazimine as an inhibitor of Cx46-specific cell-cell communication. Clofazimine attenuates proliferation, self-renewal, and tumor growth and synergizes with temozolomide to induce apoptosis. Although clofazimine does not cross the blood-brain barrier, the combination of clofazimine derivatives optimized for brain penetrance with standard-of-care therapies may target glioblastoma CSCs. Furthermore, these results demonstrate the importance of targeting cell-cell communication as an anti-cancer therapy.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.celrep.2019.03.079DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6497083PMC
April 2019

Investigational chemotherapy and novel pharmacokinetic mechanisms for the treatment of breast cancer brain metastases.

Pharmacol Res 2018 06 28;132:47-68. Epub 2018 Mar 28.

West Virginia University, Health Sciences Center, School of Pharmacy, Department of Basic Pharmaceutical Sciences, Morgantown, WV 26506, USA. Electronic address:

In women, breast cancer is the most common cancer diagnosis and second most common cause of cancer death. More than half of breast cancer patients will develop metastases to the bone, liver, lung, or brain. Breast cancer brain metastases (BCBM) confers a poor prognosis, as current therapeutic options of surgery, radiation, and chemotherapy rarely significantly extend life and are considered palliative. Within the realm of chemotherapy, the last decade has seen an explosion of novel chemotherapeutics involving targeting agents and unique dosage forms. We provide a historical overview of BCBM chemotherapy, review the mechanisms of new agents such as poly-ADP ribose polymerase inhibitors, cyclin-dependent kinase 4/6 inhibitors, phosphatidyl inositol 3-kinaseinhibitors, estrogen pathway antagonists for hormone-receptor positive BCBM; tyrosine kinase inhibitors, antibodies, and conjugates for HER2 BCBM; repurposed cytotoxic chemotherapy for triple negative BCBM; and the utilization of these new agents and formulations in ongoing clinical trials. The mechanisms of novel dosage formulations such as nanoparticles, liposomes, pegylation, the concepts of enhanced permeation and retention, and drugs utilizing these concepts involved in clinical trials are also discussed. These new treatments provide a promising outlook in the treatment of BCBM.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.phrs.2018.03.021DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5997530PMC
June 2018