搜索结果: 'methocult media formulations for mouse hematopoietic cells serum containing'

Induced pluripotent stem cells (IPS) are an artificially derived type of pluripotent stem cell,showing many of the same characteristics as natural pluripotent stem cells. IPS are a hopeful therapeutic model; however there is a critical need to determine their response to environmental toxins. Effects of arsenic on cells have been studied extensively; however,its effect on IPS is yet to be elucidated. Arsenic trioxide (ATO) has been shown to inhibit cell proliferation,induce apoptosis and genotoxicity in many cells. Based on ATOs action in other cells,we hypothesize that it will induce alterations in morphology,inhibit cell viability and induce a genotoxic effect on IPS. Cells were treated for 24 hours with ATO (0-9 µg/mL). Cell morphology,viability and DNA damage were documented. Results indicated sufficient changes in morphology of cell colonies mainly in cell ability to maintain grouping and ability to remain adherent. Cell viability decreased in a dose dependent manner. There were significant increases in tail length and moment as well as destruction of intact DNA as concentration increased. Exposure to ATO resulted in a reproducible dose dependent sequence of events marked by changes in morphology,decrease of cell viability,and induction of genotoxicity in IPS. View Publication

The study introduces a new immunotherapy for treating melanoma and other cancers by developing a PROTAC that degrades NR4A1,an intracellular nuclear factor that plays a crucial role in immune suppression. An effective cancer therapy requires killing cancer cells and targeting the tumor microenvironment (TME). Searching for molecules critical for multiple cell types in the TME,we identified NR4A1 as one such molecule that can maintain the immune suppressive TME. Here,we establish NR4A1 as a valid target for cancer immunotherapy and describe a first-of-its-kind proteolysis-targeting chimera (PROTAC,named NR-V04) against NR4A1. NR-V04 degrades NR4A1 within hours in vitro and exhibits long-lasting NR4A1 degradation in tumors with an excellent safety profile. NR-V04 inhibits and frequently eradicates established tumors. At the mechanistic level,NR-V04 induces the tumor-infiltrating (TI) B cells and effector memory CD8+ T (Tem) cells and reduces monocytic myeloid-derived suppressor cells (m-MDSC),all of which are known to be clinically relevant immune cell populations in human melanomas. Overall,NR-V04–mediated NR4A1 degradation holds promise for enhancing anticancer immune responses and offers a new avenue for treating various types of cancers such as melanoma. Graphical Abstract View Publication

Autophagy that is induced by starvation or cellular stress can enable cancer cell survival by sustaining energy homeostasis and eliminating damaged organelles and proteins. In response to stress,cancer cells have been reported to accumulate the protein p62/SQSTM1 (p62),but its role in the regulation of autophagy is controversial. Here,we report that the plant phytoalexin resveratrol (RSV) triggers autophagy in imatinib-sensitive and imatinib-resistant chronic myelogenous leukemia (CML) cells via JNK-dependent accumulation of p62. JNK inhibition or p62 knockdown prevented RSV-mediated autophagy and antileukemic effects. RSV also stimulated AMPK,thereby inhibiting the mTOR pathway. AMPK knockdown or mTOR overexpression impaired RSV-induced autophagy but not JNK activation. Lastly,p62 expression and autophagy in CD34+ progenitors from patients with CML was induced by RSV,and disrupting autophagy protected CD34+ CML cells from RSV-mediated cell death. We concluded that RSV triggered autophagic cell death in CML cells via both JNK-mediated p62 overexpression and AMPK activation. Our findings show that the JNK and AMPK pathways can cooperate to eliminate CML cells via autophagy. View Publication

Defects in apoptosis contribute to poor outcome in pediatric acute lymphoblastic leukemia (ALL),calling for novel strategies that counter apoptosis resistance. Here,we demonstrate for the first time that small molecule inhibitors of the antiapoptotic protein XIAP cooperate with TRAIL to induce apoptosis in childhood acute leukemia cells. XIAP inhibitors at subtoxic concentrations,but not a structurally related control compound,synergize with TRAIL to trigger apoptosis and to inhibit clonogenic survival of acute leukemia cells,whereas they do not affect viability of normal peripheral blood lymphocytes,suggesting some tumor selectivity. Analysis of signaling pathways reveals that XIAP inhibitors enhance TRAIL-induced activation of caspases,loss of mitochondrial membrane potential,and cytochrome c release in a caspase-dependent manner,indicating that they promote a caspase-dependent feedback mitochondrial amplification loop. Of note,XIAP inhibitors even overcome Bcl-2-mediated resistance to TRAIL by enhancing Bcl-2 cleavage and Bak conformational change. Importantly,XIAP inhibitors kill leukemic blasts from children with ALL ex vivo and cooperate with TRAIL to induce apoptosis. In vivo,they significantly reduce leukemic burden in a mouse model of pediatric ALL engrafted in non-obese diabetic/severe combined immunodeficient (NOD/SCID) mice. Thus,XIAP inhibitors present a promising novel approach for apoptosis-based therapy of childhood ALL. View Publication

SPARC is an extracellular matrix protein that exerts pleiotropic effects on extracellular matrix organization,growth factor availability,cell adhesion,differentiation,and immunity in cancer. Chronic myelogenous leukemia (CML) cells resistant to the BCR-ABL inhibitor imatinib (IM-R cells) were found to overexpress SPARC mRNA. In this study,we show that imatinib triggers SPARC accumulation in a variety of tyrosine kinase inhibitor (TKI)-resistant CML cell lines. SPARC silencing in IM-R cells restored imatinib sensitivity,whereas enforced SPARC expression in imatinib-sensitive cells promoted viability as well as protection against imatinib-mediated apoptosis. Notably,we found that the protective effect of SPARC required intracellular retention inside cells. Accordingly,SPARC was not secreted into the culture medium of IM-R cells. Increased SPARC expression was intimately linked to persistent activation of the Fyn/ERK kinase signaling axis. Pharmacologic inhibition of this pathway or siRNA-mediated knockdown of Fyn kinase resensitized IM-R cells to imatinib. In support of our findings,increased levels of SPARC mRNA were documented in blood cells from CML patients after 1 year of imatinib therapy compared with initial diagnosis. Taken together,our results highlight an important role for the Fyn/ERK signaling pathway in imatinib-resistant cells that is driven by accumulation of intracellular SPARC. View Publication