Cesar Andres Garcia Jr.

All Publications

• Reduced Cas9 transgene silencing by incorporation of intron sequences. Nature communications Arana, S., Du, P. P., Vaughan-Jackson, A., Enright, N., Spees, K., Valbuena, R., Garcia, C. A., Nguyen, T., Venida, A., Seczynska, M., Bintu, L., Lehner, P. J., Prolo, L. M., Bassik, M. C. 2025; 16 (1): 10656

  Abstract

  Silencing remains a significant challenge for exogenous gene expression, limiting both the penetrance and expressivity of transgenes. In particular, silencing of Cas9 expression is a major technical limitation for many gene editing and CRISPR screening applications. Here, we demonstrate that including introns in Cas9 expression cassettes significantly reduces silencing across multiple cell lines. Notably, the incorporation of an intron into a CRISPRa construct results in reduced silencing, increased expression levels, and markedly enhanced activation of target genes. We investigate diverse intron sequences and discover that T-rich introns over 2 kb confer the greatest protection against silencing. In addition, we find that introns can work synergistically with chromatin opening elements to further mitigate silencing, suggesting regulatory mechanisms are acting at both the DNA and RNA level to silence exogenous genes. Our work highlights the potential of introns to optimize genetic constructs for enhanced expression and improved cellular engineering requiring constitutive expression of large transgenes.

  View details for DOI 10.1038/s41467-025-65669-0

  View details for PubMedID 41309578

  View details for PubMedCentralID PMC12660324

• Disrupting BMAL1 enhances Temozolomide efficacy and abolishes circadian timing effects in pediatric high-grade gliomas Nettnin, E., Garcia, C., Sayed, F., Guinle, M., Gibson, E., Prolo, L. OXFORD UNIV PRESS INC. 2025: v340

  View details for DOI 10.1093/neuonc/noaf201.1340

  View details for Web of Science ID 001612035200038

• Macropinocytosis as a novel target for pediatric high grade glioma therapy Nguyen, T., Spees, K., Garcia, C., Arana, S., Du, P., Levin-Konigsberg, R., Vaughan-Jackson, A., Nettnin, E., Bassik, M., Prolo, L. OXFORD UNIV PRESS INC. 2025: v179-v180

  View details for DOI 10.1093/neuonc/noaf201.0709

  View details for Web of Science ID 001613298600026

• Circadian rhythms in pediatric high-grade gliomas may contribute to treatment efficacy. Scientific reports Nettnin, E. A., Garcia, C. A., Sayed, F. F., Schonfeld, E., Nguyen, T., Guinle, M. I., Petritsch, C. K., Gibson, E. M., Prolo, L. M. 2025; 15 (1): 32010

  Abstract

  Pediatric high-grade gliomas (pHGG) are highly invasive with poor survival outcomes. Timing of Temozolomide administration has been shown to affect survival of adult patients with glioblastoma. We investigated whether pHGGs express circadian genes rhythmically and whether underlying rhythms affect Temozolomide sensitivity. Circadian gene expression in pediatric gliomas was analyzed using PedcBioPortal. Immunoblotting was used to assess protein levels in patient-derived pHGG lines and in high- and low- grade (pLGG) glioma specimens. Rhythmic gene expression in pHGG lines was measured via qPCR, and Temozolomide efficacy was tested during peak versus trough Bmal1 expression. Patient data revealed significantly different mRNA expression in multiple circadian genes between pHGGs and pLGGs, including higher Bmal1 expression in pHGG specimens and lower Rev-Erbα expression. Significantly higher BMAL1 and CLOCK protein levels and lower REV-ERBα were present in pHGG versus pLGG tissue specimens. Our three pHGG lines displayed rhythmic Bmal1 and Rev-Erbα expression post-synchronization. We found significantly decreased proliferation when Temozolomide was applied during trough versus peak Bmal1 expression. The positive arm of the circadian clock appears upregulated in pHGGs compared to pLGGs. Pediatric HGGs rhythmically express circadian genes and exhibit differential Temozolomide sensitivity based on timing of administration.

  View details for DOI 10.1038/s41598-025-17461-9

  View details for PubMedID 40887493

  View details for PubMedCentralID 6395056

• Prediction of seizure risk after repetitive mild traumatic brain injury in childhood. Journal of neurosurgery. Pediatrics Jin, M. C., Ravi, K., Wu, A., Garcia, C. A., Rodrigues, A. J., Savchuk, S., Ruiz Colón, G. D., Kakusa, B. W., Parker, J. J., Grant, G. A., Prolo, L. M. 2025: 1-10

  Abstract

  Despite the known negative physiological impact of repeated mild head trauma events, their multiplicative impact on long-term seizure risk remains unclear. The objective of this study was to evaluate how multiple mild traumatic brain injuries (mTBIs) impact long-term seizure risk by testing 3 distinct machine learning approaches. Baseline and injury-specific characteristics were incorporated to enhance prognostication of individual seizure risk.Children with at least 1 mTBI event without prior evidence of seizure or antiepileptic drug treatment, from 2003 to 2021, were identified from a nationally sourced administrative claims database. The primary outcome of interest was a seizure event after mTBI, defined by qualifying principal diagnosis codes. Time-varying multivariable Cox regression was used to assess the impact of repeated mTBI.A total of 156,118 children (mean age 11.7 ± 4.7 years) were included, with a median follow-up duration of 22.6 months (IQR 9.2-45.4 months). Among patients who experienced seizure after mTBI, the median time to seizure was 306 days. Seizures among those with radiographic findings and/or loss of consciousness occurred earlier (median time to seizure 112.5 days [imaging findings only, IQR 5-526.25 days], 80 days [loss of consciousness only, IQR 7-652 days], 22 days [both, IQR 5-192 days]). Both mTBI without and with short-term loss of consciousness resulted in increasing seizure risk with repeated trauma (HR 1.196, 95% CI 1.082-1.322; HR 2.025, 95% CI 1.828-2.244; respectively). The random survival forest approach achieved fixed-time areas under the receiver operating characteristic curve of 0.780 and 0.777 at 30 and 90 days after mTBI, and children predicted at high risk by the final model experienced a significantly higher burden of early seizure after mTBI (46.7% within the first 30 days vs 17.7% and 19.9% of children at low and medium risk). A simplified model using the top 12 contributing features achieved 95% of the full model's performance in the validation set.A novel machine learning model was developed and validated for personalized prediction of long-term seizure risk following multiple mTBIs. Model performance remained robust with a limited feature set, suggesting the feasibility of real-time incorporation into clinical workflows for individualized prognostication following each repeat mTBI event. In children predicted to be at high risk, early intervention should be considered.

  View details for DOI 10.3171/2025.1.PEDS2436

  View details for PubMedID 40279715

• THE ROLE OF MAP4K4 IN TUMOR CELL INVASION OBSERVED IN A 3D IN VITRO MODEL OF PEDIATRIC GLIOBLASTOMA Garcia, C., Nettnin, E., Arana, S., Nguyen, T., Guinle, M., Wilson, C., Petritsch, C. K., Bassik, M. C., Prolo, L. M. OXFORD UNIV PRESS INC. 2024

  View details for DOI 10.1093/neuonc/noae165.0226

  View details for Web of Science ID 001362572400036

• PEDIATRIC GLIOMAS EXPRESS CIRCADIAN GENES AND DEMONSTRATE CIRCADIAN REGULATION OF TEMOZOLOMIDE SENSITIVITY Nettnin, E. A., Garcia, C. A., Schonfeld, E., Mehl, L. C., Guinle, M., Petritsch, C. K., Gibson, E. M., Prolo, L. M. OXFORD UNIV PRESS INC. 2024

  View details for DOI 10.1093/neuonc/noae165.0157

  View details for Web of Science ID 001362582300007

• BIOPROCESSING OF VIABLE SURGICAL PEDIATRIC BRAIN TUMOR SPECIMENS FOR GENOME-GUIDED PERSONALIZED DRUG TESTING Nasajpour, E., Tran, C., Garcia, C., Xing, L., Lyle, G., Guinle, M., Bagley, B., Mahaney, K., Vogel, H., Learned, K., Vaske, O., Grant, G., Prolo, L., Maher, C., Petritsch, C. OXFORD UNIV PRESS INC. 2024

  View details for DOI 10.1093/neuonc/noae165.0214

  View details for Web of Science ID 001362581000012

• CDC42BPA::BRAF represents a novel fusion in desmoplastic infantile ganglioglioma/desmoplastic infantile astrocytoma. Neuro-oncology advances Barros Guinle, M. I., Nirschl, J. J., Xing, Y. L., Nettnin, E. A., Arana, S., Feng, Z. P., Nasajpour, E., Pronina, A., Garcia, C. A., Grant, G. A., Vogel, H., Yeom, K. W., Prolo, L. M., Petritsch, C. K. 2024; 6 (1): vdae050

  View details for DOI 10.1093/noajnl/vdae050

  View details for PubMedID 38741773

  View details for PubMedCentralID PMC11089409

• Review: therapeutic approaches for circadian modulation of the glioma microenvironment. Frontiers in oncology Nettnin, E. A., Nguyen, T., Arana, S., Barros Guinle, M. I., Garcia, C. A., Gibson, E. M., Prolo, L. M. 2023; 13: 1295030

  Abstract

  High-grade gliomas are malignant brain tumors that are characteristically hard to treat because of their nature; they grow quickly and invasively through the brain tissue and develop chemoradiation resistance in adults. There is also a distinct lack of targeted treatment options in the pediatric population for this tumor type to date. Several approaches to overcome therapeutic resistance have been explored, including targeted therapy to growth pathways (ie. EGFR and VEGF inhibitors), epigenetic modulators, and immunotherapies such as Chimeric Antigen Receptor T-cell and vaccine therapies. One new promising approach relies on the timing of chemotherapy administration based on intrinsic circadian rhythms. Recent work in glioblastoma has demonstrated temporal variations in chemosensitivity and, thus, improved survival based on treatment time of day. This may be due to intrinsic rhythms of the glioma cells, permeability of the blood brain barrier to chemotherapy agents, the tumor immune microenvironment, or another unknown mechanism. We review the literature to discuss chronotherapeutic approaches to high-grade glioma treatment, circadian regulation of the immune system and tumor microenvironment in gliomas. We further discuss how these two areas may be combined to temporally regulate and/or improve the effectiveness of immunotherapies.

  View details for DOI 10.3389/fonc.2023.1295030

  View details for PubMedID 38173841

  View details for PubMedCentralID PMC10762863

• Review: therapeutic approaches for circadian modulation of the glioma microenvironment Fronteirs in Oncology Nettnin, E. A., Nguyen, T., Arana, S., Barros Guinle, M., Garcia, C. A., Gibson, E. M., Prolo, L. M. 2023: 1295030

  Abstract

  High-grade gliomas are malignant brain tumors that are characteristically hard to treat because of their nature; they grow quickly and invasively through the brain tissue and develop chemoradiation resistance in adults. There is also a distinct lack of targeted treatment options in the pediatric population for this tumor type to date. Several approaches to overcome therapeutic resistance have been explored, including targeted therapy to growth pathways (ie. EGFR and VEGF inhibitors), epigenetic modulators, and immunotherapies such as Chimeric Antigen Receptor T-cell and vaccine therapies. One new promising approach relies on the timing of chemotherapy administration based on intrinsic circadian rhythms. Recent work in glioblastoma has demonstrated temporal variations in chemosensitivity and, thus, improved survival based on treatment time of day. This may be due to intrinsic rhythms of the glioma cells, permeability of the blood brain barrier to chemotherapy agents, the tumor immune microenvironment, or another unknown mechanism. We review the literature to discuss chronotherapeutic approaches to high-grade glioma treatment, circadian regulation of the immune system and tumor microenvironment in gliomas. We further discuss how these two areas may be combined to temporally regulate and/or improve the effectiveness of immunotherapies.

  View details for DOI 10.3389/fonc.2023.1295030

  View details for PubMedCentralID PMC10762863

• Behavior of glioblastoma brain tumor stem cells following a suborbital rocket flight: reaching the "edge" of outer space. NPJ microgravity Garcia, C. A., Suárez-Meade, P., Brooks, M., Bhargav, A. G., Freeman, M. L., Harvey, L. M., Quinn, J., Quiñones-Hinojosa, A. 2023; 9 (1): 92

  Abstract

  The emerging arena of space exploration has created opportunities to study cancer cell biology in the environments of microgravity and hypergravity. Studying cellular behavior in altered gravity conditions has allowed researchers to make observations of cell function that would otherwise remain unnoticed. The patient-derived QNS108 brain tumor initiating cell line (BTIC), isolated from glioblastoma (GBM) tissue, was launched on a suborbital, parabolic rocket flight conducted by EXOS Aerospace Systems & Technologies. All biologicals and appropriate ground controls were secured post-launch and transported back to our research facility. Cells from the rocket-flight and ground-based controls were isolated from the culture containers and expanded on adherent flasks for two weeks. In vitro migration, proliferation, and stemness assays were performed. Following cell expansion, male nude mice were intracranially injected with either ground-control (GC) or rocket-flight (RF) exposed cells to assess tumorigenic capacity (n = 5 per group). Patient-derived QNS108 BTICs exposed to RF displayed more aggressive tumor growth than the GC cells in vitro and in vivo. RF cells showed significantly higher migration (p < 0.0000) and stemness profiles (p < 0.01) when compared to GC cells. Further, RF cells, when implanted in vivo in the brain of rodents had larger tumor-associated cystic growth areas (p = 0.00029) and decreased survival (p = 0.0172) as compared to those animals that had GC cells implanted.

  View details for DOI 10.1038/s41526-023-00341-9

  View details for PubMedID 38110398

  View details for PubMedCentralID PMC10728190

• CDC42BPA::BRAF REPRESENTS A NOVEL FUSION IN DESMOPLASTIC INFANTILE GLIOMA Guinle, M., Nettnin, E. A., Nasajpour, E., Nirschl, J., Garcia, C. A., Vogel, H., Yeom, K., Prolo, L., Petritsch, C. OXFORD UNIV PRESS INC. 2023

  View details for Web of Science ID 001115245400685

• BIOPROCESSING OF SURGICAL PEDIATRIC BRAIN TUMOR SPECIMENS FOR GENOME-GUIDED PERSONALIZED DRUG TESTING Nasajpour, E., Tran, C., Garcia, C., Lyle, G., Guinle, M., Bagley, B. A., Lancero, H., Gibson, E. E., Schouten, T., Mahaney, K., Vogel, H., Learned, K., Vaske, O., Grant, G. A., Prolo, L. M., Petritsch, C. K. OXFORD UNIV PRESS INC. 2023

  View details for DOI 10.1093/neuonc/noad073.039

  View details for Web of Science ID 001023504300040

• THERAPY-INDUCED CHANGES BY BRAF AND MEK INHIBITORS IN BRAF V600E-MUTATED GLIOMA MODELS PROVIDE POTENTIAL NOVEL THERAPEUTIC OPPORTUNITIES Park, J., Lancero, H., Nasajpour, E., Garcia, C., Prolo, L., Grant, G., Petritsch, C. OXFORD UNIV PRESS INC. 2022: 34

  View details for Web of Science ID 000888571000135

• BIOPROCESSING OF SURGICAL PEDIATRIC BRAIN TUMOR SPECIMENS FOR GENOME-GUIDED PERSONALIZED DRUG TESTING Nasajpour, E., Lyle, G., Lancero, H., Garcia, C., Learned, K., Gibson, E., Tran, C., Schouten, T., Vogel, H., Mahaney, K., Prolo, L., Vaske, O., Grant, G., Petritsch, C. OXFORD UNIV PRESS INC. 2022: 232

  View details for Web of Science ID 000888571001208

• 5-Aminolevulinic Acid Imaging of Malignant Glioma. Surgical oncology clinics of North America Li, G., Rodrigues, A., Kim, L., Garcia, C., Jain, S., Zhang, M., Hayden-Gephart, M. 2022; 31 (4): 581-593

  Abstract

  High-grade glioma is the most common malignant primary brain tumor in adults. Glioma infiltration renders it difficult to treat and likely to recur. Increasing the extent of resection has been associated with improving progression-free survival and overall survival by several months. The introduction of 5-aminolevulinic acid (5-ALA) fluorescence-guided surgery has allowed surgeons to better differentiate between neoplastic tissue and normal tissue, thus achieving greater extent of resection. The development of new intraoperative imaging modalities in combination with 5-ALA may provide additional benefits for glioma patients.

  View details for DOI 10.1016/j.soc.2022.06.002

  View details for PubMedID 36243495

• Development of an Integrated Risk Scale for Prediction of Shunt Placement After Neonatal Intraventricular Hemorrhage Jin, M. C., Parker, J. J., Rodrigues, A., Colon, G. R., Garcia, C. A., Mahaney, K. B., Grant, G. A., Prolo, L. M. OXFORD UNIV PRESS INC. 2022: 37-38

  View details for Web of Science ID 000783218700040

• Development of an integrated risk scale for prediction of shunt placement after neonatal intraventricular hemorrhage. Journal of neurosurgery. Pediatrics Jin, M. C., Parker, J. J., Rodrigues, A. J., Ruiz Colón, G. D., Garcia, C. A., Mahaney, K. B., Grant, G. A., Prolo, L. M. 2022: 1-10

  Abstract

  Neonatal intraventricular hemorrhage (IVH) is a major cause of mortality and morbidity, particularly following premature birth. Even after the acute phase, posthemorrhagic hydrocephalus is a long-term complication, frequently requiring permanent ventriculoperitoneal shunt (VPS) placement. Currently, there are no risk classification methods integrating the constellation of clinical data to predict short- and long-term prognosis in neonatal IVH. To address this need, the authors developed a two-part machine learning approach for predicting short- and long-term outcomes after diagnosis of neonatal IVH. Integrating both maternal and neonatal characteristics, they developed a binary classifier to predict short-term mortality risk and a clinical scale to predict the long-term risk of VPS placement.Neonates with IVH were identified from the Optum Clinformatics Data Mart administrative claims database. Matched maternal and childbirth characteristics were obtained for all patients. The primary endpoints of interest were short-term (30 day) mortality and long-term VPS placement. Classification of short-term mortality risk was evaluated using 5 different machine learning approaches and the best-performing method was validated using a withheld validation subset. Prediction of long-term shunt risk was performed using a multivariable Cox regression model with stepwise variable selection, which was subsequently converted to an easily applied integer risk scale.A total of 5926 neonates with IVH were identified. Most patients were born before 32 weeks' gestation (67.2%) and with low birth weight (81.2%). Empirical 30-day mortality risk was 10.9% across all IVH grades and highest among grade IV IVH (34.3%). Among the neonates who survived > 30 days, actuarial 12-month postdiagnosis risk of shunt placement was 5.4% across all IVH grades and 31.3% for grade IV IVH. The optimal short-term risk classifier was a random forest model achieving an area under the receiver operating characteristic curve of 0.882 with important predictors ranging from gestational age to diverse comorbid medical conditions. Selected features for long-term shunt risk stratification were IVH grade, respiratory distress syndrome, disseminated intravascular coagulation, and maternal preeclampsia or eclampsia. An integer risk scale, termed the Shunt Prediction After IVH in Neonates (SPAIN) scale, was developed from these 4 features, which, evaluated on withheld cases, demonstrated improved risk stratification compared with IVH grade alone (Harrell's concordance index 0.869 vs 0.852).In a large cohort of neonates with IVH, the authors developed a two-pronged, integrated, risk classification approach to anticipate short-term mortality and long-term shunt risk. The application of such approaches may improve the prognostication of outcomes and identification of higher-risk individuals who warrant careful surveillance and early intervention.

  View details for DOI 10.3171/2021.11.PEDS21390

  View details for PubMedID 35090135

• Functional Characterization of Brain Tumor-Initiating Cells and Establishment of GBM Preclinical Models that Incorporate Heterogeneity, Therapy, and Sex Differences MOLECULAR CANCER THERAPEUTICS Garcia, C. A., Bhargav, A. G., Brooks, M., Suarez-Meade, P., Mondal, S. K., Zarco, N., ReFaey, K., Jentoft, M., Middlebrooks, E. H., Snuderl, M., Carrano, A., Guerrero-Cazares, H., Schiapparelli, P., Sarabia-Estrada, R., Quinones-Hinojosa, A. 2021; 20 (12): 2585-2597

  Abstract

  Glioblastoma (GBM) is the most common primary brain cancer in adults where tumor cell heterogeneity and sex differences influence clinical outcomes. Here, we functionally characterize three male and three female patient-derived GBM cell lines, identify protumorigenic BTICs, and create novel male and female preclinical models of GBM. Cell lines were evaluated on the following features: proliferation, stemness, migration, tumorigenesis, clinical characteristics, and sensitivity to radiation, TMZ, rhTNFSF10 (rhTRAIL), and rhBMP4 All cell lines were classified as GBM according to epigenetic subtyping, were heterogenous and functionally distinct from one another, and re-capitulated features of the original patient tumor. In establishing male and female preclinical models, it was found that two male-derived GBM cell lines (QNS108 and QNS120) and one female-derived GBM cell line (QNS315) grew at a faster rate in female mice brains. One male-derived GBM cell line (QNS108) decreased survival in female mice in comparison with male mice. However, no survival differences were observed for mice injected with a female-derived cell line (QNS315). In summary, a panel of six GBM patient-derived cell lines were functionally characterized, and it was shown that BTIC lines can be used to construct sex-specific models with differential phenotypes for additional studies.

  View details for DOI 10.1158/1535-7163.MCT-20-0547

  View details for Web of Science ID 000728208600001

  View details for PubMedID 34465594

  View details for PubMedCentralID PMC8687628

• An Analysis of Public Interest in Elective Neurosurgical Procedures during the COVID-19 Pandemic through Online Search Engine Trends. World neurosurgery Feng, A. Y., Garcia, C. A., Jin, M. C., Ho, A. L., Li, G. n., Grant, G. n., Ratliff, J. n., Skirboll, S. L. 2021

  Abstract

  In the wake of the COVID-19 pandemic, the Centers for Medicare & Medicaid Services (CMS) has recommended the temporary cessation of all elective surgeries. The effects on patients' interest of elective neurosurgical procedures are currently unexplored.Using Google Trends (GT), search terms of seven different neurosurgical procedure categories (Trauma, Spine, Tumor, Movement Disorder, Epilepsy, Endovascular, and Miscellaneous) were assessed in terms of relative search volume (RSV) between January 2015 and September 2020. Analyses of search terms were performed for over the short-term (Feb 18th, 2020-Apr 18th, 2020), intermediate-term (Jan 1st, 2020-May 31st, 2020) and long-term (Jan 2015-Sept 2020). State-level interest during phase I re-opening (Apr 28th, 2020-May 31st, 2020) was also evaluated.In the short-term, RSV of four categories (epilepsy, movement disorder, spine, and tumor) were significantly lower in the post-CMS announcement period. In the intermediate-term, RSV of five categories (miscellaneous, epilepsy, movement disorder, spine, and tumor) were significantly lower in the post-CMS announcement period. In the long-term, RSV of nearly all categories (endovascular, epilepsy, miscellaneous, movement disorder, spine, and tumor) were significantly lower in the post-CMS announcement period. Only the movement disorder procedure category had significantly higher RSV in states that reopened early.With the recommendation for cessation of elective surgeries, patient interest in overall elective neurosurgical procedures have dropped significantly. With gradual reopening, there has been a resurgence in some procedure types. GT has proven to be a useful tracker of patient interest and may be utilized by neurosurgical departments to facilitate outreach strategies.

  View details for DOI 10.1016/j.wneu.2020.12.143

  View details for PubMedID 33412316

• Nanomedicine Revisited: Next Generation Therapies for Brain Cancer ADVANCED THERAPEUTICS Bhargav, A. G., Mondal, S. K., Garcia, C. A., Green, J. J., Quinones-Hinojosa, A. 2020; 3 (10)

  View details for DOI 10.1002/adtp.202000118

  View details for Web of Science ID 000557247700001

• Poly(ethylene glycol)-Poly(beta-amino ester)-Based Nanoparticles for Suicide Gene Therapy Enhance Brain Penetration and Extend Survival in a Preclinical Human Glioblastoma Orthotopic Xenograft Model ACS BIOMATERIALS SCIENCE & ENGINEERING Kim, J., Mondal, S. K., Tzeng, S. Y., Rui, Y., Al-kharboosh, R., Kozielski, K. K., Bhargav, A. G., Garcia, C. A., Quinones-Hinojosa, A., Green, J. J. 2020; 6 (5): 2943-2955

  Abstract

  Glioblastoma (GBM) is the most devastating brain cancer, and cures remain elusive with currently available neurosurgical, pharmacological, and radiation approaches. While retrovirus- and adenovirus-mediated suicide gene therapy using DNA encoding herpes simplex virus-thymidine kinase (HSV-tk) and prodrug ganciclovir has been suggested as a promising strategy, a nonviral approach for treatment in an orthotopic human primary brain tumor model has not previously been demonstrated. Delivery challenges include nanoparticle penetration through brain tumors, efficient cancer cell uptake, endosomal escape to the cytosol, and biodegradability. To meet these challenges, we synthesized poly(ethylene glycol)-modified poly(beta-amino ester) (PEG-PBAE) polymers to improve extracellular delivery and coencapsulated plasmid DNA with end-modified poly(beta-amino ester) (ePBAE) polymers to improve intracellular delivery as well. We created and evaluated a library of PEG-PBAE/ePBAE nanoparticles (NPs) for effective gene therapy against two independent primary human stem-like brain tumor initiating cells, a putative target to prevent GBM recurrence. The optimally engineered PEG-PBAE/ePBAE NP formulation demonstrated 54 and 82% transfection efficacies in GBM1A and BTIC375 cells respectively, in comparison to 37 and 66% for optimized PBAE NPs without PEG. The leading PEG-PBAE NP formulation also maintained sub-250 nm particle size up to 5 h, while PBAE NPs without PEG showed aggregation over time to micrometer-sized complexes. The comparative advantage demonstrated in vitro successfully translated into improved in vivo diffusion, with a higher amount of PEG-PBAE NPs penetrating to a distance of 2 mm from the injection site. A significant increase in median survival from 53.5 to 67 days by PEG-PBAE/pHSV-tk NP and systemic ganciclovir treatment compared to a control group in orthotopic murine model of human glioblastoma demonstrates the potential of PEG-PBAE-based NPs as an effective gene therapy platform for the treatment of human brain tumors.

  View details for DOI 10.1021/acsbiomaterials.0c00116

  View details for Web of Science ID 000535188500041

  View details for PubMedID 33463272

  View details for PubMedCentralID PMC8035708

• pH-Responsive fluorescent graphene quantum dots for fluorescence-guided cancer surgery and diagnosis NANOSCALE Fan, Z., Zhou, S., Garcia, C., Fan, L., Zhou, J. 2017; 9 (15): 4928-4933

  Abstract

  Cancer remains a major cause of morbidity and mortality around the world. Improved cancer treatment requires enhancement of cancer diagnosis and detection. To achieve this goal, here we report a novel imaging probe, pH-responsive fluorescent graphene quantum dots (pRF-GQDs). pRF-GQDs were prepared by electrolysis of graphite rods in sodium p-toluenesulfonate acetonitrile solution. The resulting pRF-GQDs, which have minimal toxicity, display a sharp fluorescence transition between green and blue at pH 6.8, a pH matching the acidic extracellular microenvironment in solid tumors. We found that this unique fluorescence switch property allows tumors to be distinguished from normal tissues. In addition to fluorescence, pRF-GQDs also exhibit upconversion photoluminescence (UCPL). We demonstrate that the combination of UCPL and fluorescence switch enables detection of solid tumors of different origin at an early developmental stage. Therefore, pRF-GQDs have great potential to be used as a universal probe for fluorescence-guided cancer surgery and cancer diagnosis.

  View details for DOI 10.1039/c7nr00888k

  View details for Web of Science ID 000399429800009

  View details for PubMedID 28368056

  View details for PubMedCentralID PMC5501082

• A lupus anti-DNA autoantibody mediates autocatalytic, targeted delivery of nanoparticles to tumors ONCOTARGET Chen, Z., Patel, J. M., Noble, P. W., Garcia, C., Hong, Z., Hansen, J. E., Zhou, J. 2016; 7 (37): 59965-59975

  Abstract

  Strategies to target nanoparticles to tumors that rely on surface modification with ligands that bind molecules overexpressed on cancer cells or the tumor neovasculature suffer from a major limitation: with delivery of toxic agents the amount of molecules available for targeting decreases with time; consequently, the efficiency of nanoparticle delivery is reduced. To overcome this limitation, here we propose an autocatalytic tumor-targeting mechanism based on targeting extracellular DNA (exDNA). exDNA is enriched in the tumor microenviroment and increases with treatment with cytotoxic agents, such as doxorubicin (DOX), due to release of DNA by dying tumor cells. We tested this approach using poly(lactic-co-glycolic acid) (PLGA) nanoparticles surface-conjugated with fragments of 3E10 (3E10EN), a lupus anti-DNA autoantibody. We demonstrated that 3E10EN-conjugated nanoparticles bound to DNA and preferentially localized to tumors in vivo. The efficiency of tumor localization of 3E10EN-conjugated, DOX-loaded nanoparticles increased with time and subsequent treatments, demonstrating an autocatalytic effect. 3E10EN-conjugated DOX-loaded nanoparticles exhibited a significant anti-tumor effect that was superior to all controls. This work demonstrates the promise of autocatalytic drug delivery mechanisms and establishes proof of concept for a new anti-DNA autoantibody-based approach for enhancing delivery of nanoparticles to tumors.

  View details for DOI 10.18632/oncotarget.11015

  View details for Web of Science ID 000387153900094

  View details for PubMedID 27494868

  View details for PubMedCentralID PMC5312362