363 A Dual PI3K/mTOR Inhibitor DS-7423 is Effective in in Vitro and in Vivo Models of Glioblastoma Cell Lines and Glioma Stem Cells

Abstract Poly (ADP-ribose) polymerase (PARP) inhibition could enhance the efficacy of temozolomide and prolong survival in patients with glioblastoma. The aim of this study was to evaluate the combination of the PARP inhibitor olaparib with temozolomide in the treatment of glioblastoma by evaluating in vitro and in vivo antitumor effects in an experimental glioblastoma model. The authors investigated antitumor effects of olaparib on temozolomide-induced cytotoxicity on O6-methylguanine methyltransferase (MGMT) promotor methylated (U87MG, U251MG) and MGMT promotor unmethylated (T98G) glioblastoma cell lines using in vitro cell viability and apoptosis assay. We found that the combination of olaparib with temozolomide enhanced temozolomide-induced cytotoxicity in all glioblastoma cell lines regardless of the status of MGMT promotor methylation. For in vivo studies, nude mice bearing orthotopically xenografted glioblastoma cell lines (U87MG) were randomized to four experimental groups: (i) untreated, (ii) temozolomide alone, (iii) olaprib alone and, (iv) olaparib+temozolomide. Mice were treated daily for 4 weeks and monitored for tumor growth, and survival. However, the addition of olaparib had no impact on the efficacy of temozolomide. The combination of PARP inhibitor olaparib with temozolomide could be an effective therapeutic approach for treatment of glioblastoma regardless of MGMT promotor methylation status, although the efficacy still should be evaluated by in vivo and clinical studies.

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STEM-26. SMALL MOLECULE DRUG CBL0137 INHIBITS THE FACT COMPLEX AND SENSITIZES GLIOBLASTOMA CANCER STEM CELLS TO RADIOTHERAPY

Neuro-Oncology ◽

10.1093/neuonc/noaa215.843 ◽

2020 ◽

Vol 22 (Supplement_2) ◽

pp. ii201-ii202

Author(s):

Miranda Tallman ◽

Abigail Zalenski ◽

Amanda Deighen ◽

Morgan Schrock ◽

Sherry Mortach ◽

...

Keyword(s):

Stem Cells ◽

Cancer Stem Cells ◽

High Rate ◽

Orthotopic Model ◽

In Vivo Models ◽

Specific Cytotoxicity ◽

Treatment Paradigm ◽

Cancer Agent

Abstract Glioblastoma (GBM) is a malignant brain tumor with nearly universal recurrence. GBM cancer stem cells (CSCs), a subpopulation of radio- and chemo-resistant cancer cells capable of self-renewal, contribute to the high rate of recurrence. The anti-cancer agent, CBL0137, inhibits the FACT (facilitates chromatin transcription) complex leading to cancer cell specific cytotoxicity. Here, we show that CBL0137 sensitized GBM CSCs to radiotherapy using both in vitro and in vivo models. Treatment of CBL0137 combined with radiotherapy led to increased DNA damage in GBM patient specimens and failure to resolve the damage led to decreased cell viability. Using clonogenic assays, we confirmed that CBL0137 radiosensitized the CSCs. To validate that combination therapy impacted CSCs, we used an in vivo subcutaneous model and showed a decrease in the frequency of cancer stem cells present in tumors as well as decreased tumor volume. Using an orthotopic model of GBM, we confirmed that treatment with CBL0137 followed by radiotherapy led to significantly increased survival compared to either treatment alone. Radiotherapy remains a critical component of patient care for GBM, even though there exists a resistant subpopulation. Radio-sensitizing agents, including CBL0137, pose an exciting treatment paradigm to increase the efficacy of irradiation, especially by inclusively targeting CSCs.

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Prrx1 promotes stemness and angiogenesis via activating TGF-β/smad pathway and upregulating proangiogenic factors in glioma

Cell Death and Disease ◽

10.1038/s41419-021-03882-7 ◽

2021 ◽

Vol 12 (6) ◽

Author(s):

Zetao Chen ◽

Yihong Chen ◽

Yan Li ◽

Weidong Lian ◽

Kehong Zheng ◽

...

Keyword(s):

Stem Cells ◽

Therapeutic Strategy ◽

Critical Role ◽

Glioma Stem Cells ◽

Promoter Regions ◽

Aberrant Expression ◽

Smad Pathway ◽

Tgf Β1

AbstractGlioma is one of the most lethal cancers with highly vascularized networks and growing evidences have identified glioma stem cells (GSCs) to account for excessive angiogenesis in glioma. Aberrant expression of paired-related homeobox1 (Prrx1) has been functionally associated with cancer stem cells including GSCs. In this study, Prrx1 was found to be markedly upregulated in glioma specimens and elevated Prrx1 expression was inversely correlated with prognosis of glioma patients. Prrx1 potentiated stemness acquisition in non-stem tumor cells (NSTCs) and stemness maintenance in GSCs, accompanied with increased expression of stemness markers such as SOX2. Prrx1 also promoted glioma angiogenesis by upregulating proangiogenic factors such as VEGF. Consistently, silencing Prrx1 markedly inhibited glioma proliferation, stemness, and angiogenesis in vivo. Using a combination of subcellular proteomics and in vitro analyses, we revealed that Prrx1 directly bound to the promoter regions of TGF-β1 gene, upregulated TGF-β1 expression, and ultimately activated the TGF-β/smad pathway. Silencing TGF-β1 mitigated the malignant behaviors induced by Prrx1. Activation of this pathway cooperates with Prrx1 to upregulate the expression of stemness-related genes and proangiogenic factors. In summary, our findings revealed that Prrx1/TGF-β/smad signal axis exerted a critical role in glioma stemness and angiogeneis. Disrupting the function of this signal axis might represent a new therapeutic strategy in glioma patients.

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Experimental Models for Studying HPV-Positive and HPV-Negative Penile Cancer: New Tools for An Old Disease

Cancers ◽

10.3390/cancers13030460 ◽

2021 ◽

Vol 13 (3) ◽

pp. 460

Author(s):

Beatriz Medeiros-Fonseca ◽

Antonio Cubilla ◽

Haissa Brito ◽

Tânia Martins ◽

Rui Medeiros ◽

...

Keyword(s):

Mouse Models ◽

Cell Lines ◽

Penile Cancer ◽

Hpv Infection ◽

Experimental Models ◽

In Vivo Models ◽

Recent Developments ◽

Key Aspects

Penile cancer is an uncommon malignancy that occurs most frequently in developing countries. Two pathways for penile carcinogenesis are currently recognized: one driven by human papillomavirus (HPV) infection and another HPV-independent route, associated with chronic inflammation. Progress on the clinical management of this disease has been slow, partly due to the lack of preclinical models for translational research. However, exciting recent developments are changing this landscape, with new in vitro and in vivo models becoming available. These include mouse models for HPV+ and HPV− penile cancer and multiple cell lines representing HPV− lesions. The present review addresses these new advances, summarizing available models, comparing their characteristics and potential uses and discussing areas that require further improvement. Recent breakthroughs achieved using these models are also discussed, particularly those developments pertaining to HPV-driven cancer. Two key aspects that still require improvement are the establishment of cell lines that can represent HPV+ penile carcinomas and the development of mouse models to study metastatic disease. Overall, the growing array of in vitro and in vivo models for penile cancer provides new and useful tools for researchers in the field and is expected to accelerate pre-clinical research on this disease.

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P-EP013. Superior migration propensity of dental pulp stem cells in in vitro and in vivo models of excitotoxic neurodegeneration

Clinical Neurophysiology ◽

10.1016/j.clinph.2021.02.176 ◽

2021 ◽

Vol 132 (8) ◽

pp. e82-e83

Author(s):

Sivapriya Senthilkumar ◽

Chaitra Venugopal ◽

K. Shobha ◽

Bindu M. Kutty ◽

Anandh Dhanushkodi

Keyword(s):

Stem Cells ◽

Dental Pulp ◽

Dental Pulp Stem Cells ◽

In Vivo Models ◽

Migration Propensity

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TAMI-73. GLIOBLASTOMA CELL POPULATIONS WITH DISTINCT ONCOGENIC PROGRAMS RELEASE PODOPLANIN AS PROCOAGULANT EXTRACELLULAR VESICLES

Neuro-Oncology ◽

10.1093/neuonc/noab196.855 ◽

2021 ◽

Vol 23 (Supplement_6) ◽

pp. vi213-vi213

Author(s):

Nadim Tawil ◽

Rayhaan Bassawon ◽

Brian Meehan ◽

Laura Montermini ◽

Ali Nehme ◽

...

Keyword(s):

Cancer Cells ◽

Cell Lines ◽

Extracellular Vesicles ◽

Glioblastoma Cell ◽

Activation Markers ◽

Increased Risk ◽

Gradient Fractionation ◽

D Dimer

Abstract BACKGROUND Vascular anomalies, including thrombosis, are a hallmark of glioblastoma (GBM) and an aftermath of dysregulated cancer cell genome and epigenome. Up-regulation of podoplanin (PDPN) by cancer cells has recently been linked to an increased risk of venous thromboembolism in glioblastoma patients. Thus, regulation of this platelet activating protein by transforming events and release from cancer cells is of considerable interest. AIMS I. Investigate the pattern of PDPN expression and characterize PDPN-expressing cellular populations in GBM. II. Evaluate the contribution of oncogenic drivers to PDPN expression in GBM models. III. Investigate the potential involvement of extracellular vesicles (EVs) as a mechanism for systemic dissemination of PDPN and tissue factor (TF). IV. Examine the role of PDPN in intratumoral and systemic thrombosis. METHODS Bioinformatics (single-cell and bulk transcriptome data mining), GBM cell lines and stem cell lines, xenograft models in mice, ELISA assays for PDPN and TF, platelet (PF4) and clotting activation markers (D-dimer), EV electron microscopy, density gradient fractionation, and nano-flow cytometry. RESULTS PDPN is expressed by distinct glioblastoma cell subpopulations (mesenchymal) and downregulated by oncogenic mutations of EGFR and IDH1 genes, via changes in chromatin modifications (EZH2) and DNA methylation, respectively. GBM cells exteriorize PDPN and/or TF as cargo of exosome-like EVs shed both in vitro and in vivo. Injection of glioma PDPN-EVs activates platelets. Increase of platelet activation (PF4) or coagulation markers (D-dimer) occurs in mice harboring the corresponding glioma xenografts expressing PDPN or TF, respectively. Co-expression of PDPN and TF by GBM cells cooperatively increases tumor microthrombosis. CONCLUSION Distinct cellular subsets drive multiple facets of GBM-associated thrombosis and may represent targets for diagnosis and intervention. We suggest that the preponderance of PDPN expression as a risk factor in glioblastoma and the involvement of platelets may merit investigating anti-platelets for potential inclusion in thrombosis management in GBM.

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