scholarly journals Cryptic developmental events determine medulloblastoma radiosensitivity and cellular heterogeneity without altering transcriptomic profile.

2020 ◽  
Author(s):  
Daniel Shiloh Malawsky ◽  
Seth Weir ◽  
Jennifer Ocasio ◽  
Ben Babcock ◽  
Taylor Dismuke ◽  
...  
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Genetically Engineered ◽  
Response To Therapy ◽  
Cellular Heterogeneity ◽  
Cerebellar Granule Neuron ◽  
Transcriptomic Profile ◽  
Precise Understanding ◽  
Genetically Engineered Mice ◽  
Long Term Survivors

Abstract Patients with medulloblastoma are typically treated with a narrow range of therapies, but may experience widely divergent outcomes; 80-90% become long-term survivors while 20% develop incurable recurrence. Transcriptomic profiling has identified four subgroups with different recurrence risks, but outcomes remain variable for individual patients within each subgroup. To gain new insight into why patients with similar-appearing tumors have variable outcomes, we examined how the timing of tumor initiation effects medulloblastomas triggered by a single, common driver mutation. We genetically-engineered mice to express an oncogenic Smo allele starting early in development in the broad lineage of neural stem cells, or later, in the more committed lineage of cerebellar granule neuron progenitors. Both groups developed medulloblastomas and no other tumors. We compared medulloblastoma progression, response to therapy, gene expression profile and cellular heterogeneity, determined by single cell transcriptomic analysis (scRNA-seq). The average transcriptomic profiles of the tumors were similar. However, stem cell-triggered medulloblastomas progressed faster, contained more OLIG2-expressing tumor stem cells, and consistently showed radioresistance. In contrast, progenitor-triggered MBs progressed slower, lost stem cell character over time and were radiosensitive. Progenitor-triggered medulloblastomas also contained more diverse stromal populations, including tumor-associated macrophages, indicating that the timing of oncogenesis affected the subsequent interactions between the tumor and microenvironment. Our findings show that developmental events in tumorigenesis may be impossible to infer from transcriptomic profile, but while remaining cryptic can nevertheless influence tumor composition and the outcome of therapy. Precise understanding of medulloblastoma pathogenesis and prognosis requires supplementing transcriptomic data with biomarkers of cellular heterogeneity.

scholarly journals Cryptic developmental events determine medulloblastoma radiosensitivity and cellular heterogeneity without altering transcriptomic profile

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Daniel Shiloh Malawsky ◽  
Seth J. Weir ◽  
Jennifer Karin Ocasio ◽  
Benjamin Babcock ◽  
Taylor Dismuke ◽  
...  
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Tumor Microenvironment ◽  
Transgenic Mice ◽  
Genetically Engineered ◽  
Neural Progenitors ◽  
Cellular Heterogeneity ◽  
Neuronal Stem Cells ◽  
Precise Understanding ◽  
Genetically Engineered Mice

AbstractIt is unclear why medulloblastoma patients receiving similar treatments experience different outcomes. Transcriptomic profiling identified subgroups with different prognoses, but in each subgroup, individuals remain at risk of incurable recurrence. To investigate why similar-appearing tumors produce variable outcomes, we analyzed medulloblastomas triggered in transgenic mice by a common driver mutation expressed at different points in brain development. We genetically engineered mice to express oncogenic SmoM2, starting in multipotent glio-neuronal stem cells, or committed neural progenitors. Both groups developed medulloblastomas with similar transcriptomic profiles. We compared medulloblastoma progression, radiosensitivity, and cellular heterogeneity, determined by single-cell transcriptomic analysis (scRNA-seq). Stem cell-triggered medulloblastomas progressed faster, contained more OLIG2-expressing stem-like cells, and consistently showed radioresistance. In contrast, progenitor-triggered MBs progressed slower, down-regulated stem-like cells and were curable with radiation. Progenitor-triggered medulloblastomas also contained more diverse stromal populations, with more Ccr2+ macrophages and fewer Igf1+ microglia, indicating that developmental events affected the subsequent tumor microenvironment. Reduced mTORC1 activity in M-Smo tumors suggests that differential Igf1 contributed to differences in phenotype. Developmental events in tumorigenesis that were obscure in transcriptomic profiles thus remained cryptic determinants of tumor composition and outcome. Precise understanding of medulloblastoma pathogenesis and prognosis requires supplementing transcriptomic/methylomic studies with analyses that resolve cellular heterogeneity.

scholarly journals DYRK1A Negatively Regulates CDK5-SOX2 Pathway and Self-Renewal of Glioblastoma Stem Cells

2021 ◽  
Vol 22 (8) ◽  
pp. 4011
Author(s):  
Brianna Chen ◽  
Dylan McCuaig-Walton ◽  
Sean Tan ◽  
Andrew P. Montgomery ◽  
Bryan W. Day ◽  
...  
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Cell Differentiation ◽  
Critical Role ◽  
Stem Cell Differentiation ◽  
Neural Progenitor Cell ◽  
Cellular Heterogeneity ◽  
Differentiation Potential ◽  
Glioblastoma Stem Cells ◽  
Glioblastoma Stem Cell

Glioblastoma display vast cellular heterogeneity, with glioblastoma stem cells (GSCs) at the apex. The critical role of GSCs in tumour growth and resistance to therapy highlights the need to delineate mechanisms that control stemness and differentiation potential of GSC. Dual-specificity tyrosine phosphorylation-regulated kinase 1A (DYRK1A) regulates neural progenitor cell differentiation, but its role in cancer stem cell differentiation is largely unknown. Herein, we demonstrate that DYRK1A kinase is crucial for the differentiation commitment of glioblastoma stem cells. DYRK1A inhibition insulates the self-renewing population of GSCs from potent differentiation-inducing signals. Mechanistically, we show that DYRK1A promotes differentiation and limits stemness acquisition via deactivation of CDK5, an unconventional kinase recently described as an oncogene. DYRK1A-dependent inactivation of CDK5 results in decreased expression of the stemness gene SOX2 and promotes the commitment of GSC to differentiate. Our investigations of the novel DYRK1A-CDK5-SOX2 pathway provide further insights into the mechanisms underlying glioblastoma stem cell maintenance.

205 SELECTIVE ANTITUMOR THERAPEUTIC EFFECT OF 5-FLUOROCYTOSINE AND INTERFERON-BETA AGAINST BREAST AND ENDOMETRIAL CANCER CELLS BY ENGINEERED STEM CELLS EXPRESSING CYTOSINE DEAMINASE AND HUMAN INTERFERON-BETA

2012 ◽  
Vol 24 (1) ◽  
pp. 215
Author(s):  
B.-R. Yi ◽  
K.-A. Hwang ◽  
K.-C. Choi
Keyword(s):  
Stem Cells ◽  
Endometrial Cancer ◽  
Stem Cell ◽  
Cell Viability ◽  
Cancer Cells ◽  
Therapeutic Efficacy ◽  
Interferon Beta ◽  
Cytosine Deaminase ◽  
Genetically Engineered ◽  
Human Interferon

When genetically engineered with chemo- or immunotherapeutic genes, stem cells can exhibit a potent therapeutic efficacy combined with their strong tumour tropism. The stem cells were genetically engineered to express a bacterial cytosine deaminase (CD) gene and/or a human interferon-β (IFN-b) gene; thus, 2 stem cell lines, HB1.F3.CD and HB1.F3.CD.IFN-b, were generated, respectively. The CD gene, one of suicide gene, can convert the nontoxic prodrug 5-fluorocytosine (5-FC) to an active form, 5-fluorouracil (5-FU), which has a powerful cytotoxic effect on cancer cells. In addition, human IFN-b is a typical cytokine having an antitumour effect. Using reverse transcription-PCR (RT-PCR), we confirmed CD and/or IFN-b gene expression in HB1.F3 (maternal stem cells) and HB1.F3.CD and HB1.F3.CD.IFN-b cells and the expression of chemoattractant ligands and receptors including stem cell factor (SCF), CXCR4, c-kit, vascular endothelial growth factor (VEGF) and VEGF receptor 2 (VEGFR2) in breast (MCF-7) and endometrial cancer (Ishikawa) cells. To determine the migratory capability of engineered stem cells, we performed a modified trans-well assay. In addition, to identify their therapeutic efficacy, we co-cultured HB1.F3.CD or HB1.F3.CD.IFN-b with breast and endometrial cancer cells and cell viability was measured by MTT assay. The engineered stem cells expressed CD and IFN-b genes and several chemoattractant molecules, SCF, CXCR4, VEGF/VEGFR2 and c-kit, were strongly expressed in breast and endometrial cancer cells. These stem cells were effectively migrated to breast and endometrial cancer cells due to chemoattractant molecules secreted by breast and endometrial cancer cells. In therapeutic efficacy, the viability of breast and endometrial cancer cells treated with 5-FC was reduced in the presence of the HB1.F3.CD and HB1.F3.CD.IFN-b cells. Cell viability was more reduced when co-cultured with HB1.F3.CD.IFN-b compared with HB1.F3.CD cells. In conclusion, the results from the present study suggest that genetically modified stem cells expressing CD and IFN-b can be used as a gene-based therapy for treating breast and endometrial cancer via their tumour tropism. This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MEST) (No. 2011-0005723).

Elimination of CD20-Expressing Cells in Multiple Myeloma by Iodine I-131 Tositumomab (Bexxar®) Correlates with Response to Therapy

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 5176-5176 ◽  
Author(s):  
Andrzej J. Jakubowiak ◽  
Malathi Hari ◽  
Tara Kendall ◽  
Yasser Khaled ◽  
Shin Mineishi ◽  
...  
Keyword(s):  
Stem Cells ◽  
Multiple Myeloma ◽  
Stem Cell ◽  
Partial Response ◽  
Clinical Outcomes ◽  
Plasma Cells ◽  
Response To Therapy ◽  
Myeloma Cells ◽  
Consolidation Treatment ◽  
Anti Cd20

Abstract It has been proposed that treatment failures in multiple myeloma (MM) are related to the chemoresistance of a subset of malignant myeloma cells with clonogenic potential to the anti-myeloma drugs (Matsui et al., Cancer Research2008, 68:190). Studies suggest that these putative myeloma stem cells (MSC) are CD138neg and express CD20, which is usually absent in more differentiated malignant plasma cells (Matsui et al., Blood2004, 15:2332). These findings provided a rationale for a treatment strategy to eliminate chemoresistant clonogenic MSC using anti-CD20 antibodies. To evaluate the clinical effects of anti-CD20 treatment, we developed a phase II trial with Bexxar as a consolidation treatment for MM. We hypothesized that Bexxar would be more efficacious than unlabeled antibody in the eradication of highly radiosensitive myeloma cells by both direct and cross-fire effects. Preclinical studies showed that tositumomab, the antibody used in Bexxar, inhibited colony formation of clonogenic myeloma cells. To be eligible for Bexxar treatment, patients must have completed at least 4 cycles of therapy (1st to 3rd line) and have measurable disease in a plateau of at least partial response (PR). To date, 10 of 30 patients have been enrolled, of which 5 were treated with Bexxar after completion of initial therapy prior to proceeding to autologous stem cell transplant (ASCT). Patients proceeding to ASCT required hematopoietic stem cells collection prior to Bexxar and 3 months after Bexxar. Eight patients are evaluable for response and toxicities. At 3 months post Bexxar, 1 patient achieved a partial response (PR), 4 patients had stable disease (SD), and 1 patient progressed (PD). At 1 year post Bexxar, 1 patient with initial PR achieved CR and remains in CR, 1 patient is in unconfirmed CR, 2 are in partial response (PR), and 3 remain in SD. After a median 20 months of followup (range 4–24), all patient are alive, 4 in continued response, 3 with SD. Hematological toxicities were mild to moderate (1 patient grade 3 and 4 patients grade 2 thrombocytopenia, 4 patients grade 2 neutropenia). Non-hematological toxicity was limited to HAMA (6 patients). Out of patients who received Bexxar prior to transplant, 3 collected stem cells post-Bexxar without problems, one requires re-collection. Three patients who proceeded to ASCT to date using the post-Bexxar stem cell collection, engrafted at 11–12 days, and had no unexpected toxicities with ASCT. We also analyzed CD20+ cells in bone marrow aspirates (BM) and stem cell collections (SCC) using samples collected from 4 patients before and after Bexxar. Bexxar treatment eliminated a median 80% of CD20+ cells (range 23–97). For a given patient, elimination of CD20+ cells from SCC correlated with elimination of CD20+ cells from BM. The most complete elimination of CD20+ cells from BM was observed in 2 patients who at 1 year achieved CR (94% and 97%), compared to patients who achieved PR (23% and 68%). We conclude that anti-CD20 consolidation treatment of myeloma patients with Bexxar used as targeted therapy against clonogenic myeloma cells is feasible and well tolerated. Clinical outcomes to date are encouraging considering that clonogenic MSC represent <5% of malignant plasma cells and delayed responses observed in this study could be expected. While early, clinical outcomes appear to correlate with the efficacy of the CD20+ cell elimination by Bexxar treatment in myeloma.

scholarly journals Adhesion Molecules Involved in Stem Cell Niche Retention During Normal Haematopoiesis and in Acute Myeloid Leukaemia

2021 ◽  
Vol 12 ◽  
Author(s):  
Julien M. P. Grenier ◽  
Céline Testut ◽  
Cyril Fauriat ◽  
Stéphane J. C. Mancini ◽  
Michel Aurrand-Lions
Keyword(s):  
Stem Cells ◽  
Drug Resistance ◽  
Stem Cell ◽  
Acute Myeloid Leukaemia ◽  
Myeloid Leukaemia ◽  
Adhesion Molecules ◽  
Molecular Mechanisms ◽  
Genetically Engineered ◽  
Cell Niche ◽  
Acute Myeloid

In the bone marrow (BM) of adult mammals, haematopoietic stem cells (HSCs) are retained in micro-anatomical structures by adhesion molecules that regulate HSC quiescence, proliferation and commitment. During decades, researchers have used engraftment to study the function of adhesion molecules in HSC’s homeostasis regulation. Since the 90’s, progress in genetically engineered mouse models has allowed a better understanding of adhesion molecules involved in HSCs regulation by BM niches and raised questions about the role of adhesion mechanisms in conferring drug resistance to cancer cells nested in the BM. This has been especially studied in acute myeloid leukaemia (AML) which was the first disease in which the concept of cancer stem cell (CSC) or leukemic stem cells (LSCs) was demonstrated. In AML, it has been proposed that LSCs propagate the disease and are able to replenish the leukemic bulk after complete remission suggesting that LSC may be endowed with drug resistance properties. However, whether such properties are due to extrinsic or intrinsic molecular mechanisms, fully or partially supported by molecular crosstalk between LSCs and surrounding BM micro-environment is still matter of debate. In this review, we focus on adhesion molecules that have been involved in HSCs or LSCs anchoring to BM niches and discuss if inhibition of such mechanism may represent new therapeutic avenues to eradicate LSCs.

scholarly journals Cell Cycle-Driven Heterogeneity: On the Road to Demystifying the Transitions between “Poised” and “Restricted” Pluripotent Cell States

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Amar M. Singh
Keyword(s):  
Cell Cycle ◽  
Stem Cells ◽  
Stem Cell ◽  
Pluripotent Stem Cells ◽  
Cell Types ◽  
Cellular Heterogeneity ◽  
The Road ◽  
Developmental Factors ◽  
On The Road ◽  
G1 Cells

Cellular heterogeneity is now considered an inherent property of most stem cell types, including pluripotent stem cells, somatic stem cells, and cancer stem cells, and this heterogeneity can exist at the epigenetic, transcriptional, and posttranscriptional levels. Several studies have indicated that the stochastic activation of signaling networks may promote heterogeneity and further that this heterogeneity may be reduced by their inhibition. But why different cells in the same culture respond in a nonuniform manner to the identical exogenous signals has remained unclear. Recent studies now demonstrate that the cell cycle position directly influences lineage specification and specifically that pluripotent stem cells initiate their differentiation from the G1 phase. These studies suggest that cells in G1 are uniquely “poised” to undergo cell specification. G1 cells are therefore more prone to respond to differentiation cues, which may explain the heterogeneity of developmental factors, such as Gata6, and pluripotency factors, such as Nanog, in stem cell cultures. Overall, this raises the possibility that G1 serves as a “Differentiation Induction Point.” In this review, we will reexamine the literature describing heterogeneity of pluripotent stem cells, while highlighting the role of the cell cycle as a major determinant.

scholarly journals Hedgehog Pathway Inhibition Hampers Sphere and Holoclone Formation in Rhabdomyosarcoma

2017 ◽  
Vol 2017 ◽  
pp. 1-14 ◽  
Author(s):  
Ana Almazán-Moga ◽  
Patricia Zarzosa ◽  
Isaac Vidal ◽  
Carla Molist ◽  
Irina Giralt ◽  
...  
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Soft Tissue ◽  
Soft Tissue Sarcoma ◽  
Common Type ◽  
Hedgehog Pathway ◽  
Cellular Heterogeneity ◽  
Self Renewal ◽  
Pathway Inhibition

Rhabdomyosarcoma (RMS) is the most common type of soft tissue sarcoma in children and can be divided into two main subtypes: embryonal (eRMS) and alveolar (aRMS). Among the cellular heterogeneity of tumors, the existence of a small fraction of cells called cancer stem cells (CSC), thought to be responsible for the onset and propagation of cancer, has been demonstrated in some neoplasia. Although the existence of CSC has been reported for eRMS, their existence in aRMS, the most malignant subtype, has not been demonstrated to date. Given the lack of suitable markers to identify this subpopulation in aRMS, we used cancer stem cell-enriched supracellular structures (spheres and holoclones) to study this subpopulation. This strategy allowed us to demonstrate the capacity of both aRMS and eRMS cells to form these structures and retain self-renewal capacity. Furthermore, cells contained in spheres and holoclones showed significant Hedgehog pathway induction, the inhibition of which (pharmacologic or genetic) impairs the formation of both holoclones and spheres. Our findings point to a crucial role of this pathway in the maintenance of these structures and suggest that Hedgehog pathway targeting in CSC may have great potential in preventing local relapses and metastases.

scholarly journals Glioblastoma Stem Cells as a New Therapeutic Target for Glioblastoma

2015 ◽  
Vol 9 ◽  
pp. CMO.S30271 ◽  
Author(s):  
Rasime Kalkan
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Signaling Pathways ◽  
Therapeutic Target ◽  
Fatal Outcome ◽  
Cellular Heterogeneity ◽  
Cell Phenotype ◽  
Glioblastoma Stem Cells ◽  
Glioblastoma Stem Cell

Primary and secondary glioblastomas (GBMs) are two distinct diseases. The genetic and epigenetic background of these tumors is highly variable. The treatment procedure for these tumors is often unsuccessful because of the cellular heterogeneity and intrinsic ability of the tumor cells to invade healthy tissues. The fatal outcome of these tumors promotes researchers to find out new markers associated with the prognosis and treatment planning. In this communication, the role of glioblastoma stem cells in tumor progression and the malignant behavior of GBMs are summarized with attention to the signaling pathways and molecular regulators that are involved in maintaining the glioblastoma stem cell phenotype. A better understanding of these stem cell-like cells is necessary for designing new effective treatments and developing novel molecular strategies to target glioblastoma stem cells. We discuss hypoxia as a new therapeutic target for GBM. We focus on the inhibition of signaling pathways, which are associated with the hypoxia-mediated maintenance of glioblastoma stem cells, and the knockdown of hypoxia-inducible factors, which could be identified as attractive molecular target approaches for GBM therapeutics.

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