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Stromal CYR61 Confers Resistance to Mitoxantrone via Spleen Tyrosine Kinase Activation in Human Acute Myeloid Leukaemia.

ABSTRACT: Approximately 50% of children with acute myeloid leukaemia (AML) relapse, despite aggressive chemotherapy. The bone marrow stromal environment protects leukaemia cells from chemotherapy (i.e., stroma-induced chemoresistance), eventually leading to recurrence. Our goal is to delineate the mechanisms underlying stroma-mediated chemoresistance in AML. We used two human bone marrow stromal cell lines, HS-5 and HS-27A, which are equally effective in protecting AML cells from chemotherapy-induced apoptosis in AML-stromal co-cultures. We found that CYR61 was highly expressed by stromal cells, and was upregulated in AML cells by both stromal cell lines. CYR61 is a secreted matricellular protein and is associated with cell-intrinsic chemoresistance in other malignancies. Here, we show that blocking stromal CYR61 activity, by neutralization or RNAi, increased mitoxantrone-induced apoptosis in AML cells in AML-stromal co-cultures, providing functional evidence for its role in stroma-mediated chemoresistance. Further, we found that spleen tyrosine kinase (SYK) mediates CYR61 signalling. Exposure to stroma increased SYK expression and activation in AML cells, and this increase required CYR61. SYK inhibition reduced stroma-dependent mitoxantrone resistance in the presence of CYR61, but not in its absence. Therefore, SYK is downstream of CYR61 and contributes to CYR61-mediated mitoxantrone resistance. The CYR61-SYK pathway represents a potential target for reducing stroma-induced chemoresistance.

SUBMITTER: Long X

PROVIDER: S-EPMC5490799 | biostudies-literature | 2015 Sep

REPOSITORIES: biostudies-literature

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Stromal CYR61 Confers Resistance to Mitoxantrone via Spleen Tyrosine Kinase Activation in Human Acute Myeloid Leukaemia.

Long Xin X Yu Yang Y Perlaky Laszlo L Man Tsz-Kwong TK Redell Michele S MS

British journal of haematology 20150514 5

Approximately 50% of children with acute myeloid leukaemia (AML) relapse, despite aggressive chemotherapy. The bone marrow stromal environment protects leukaemia cells from chemotherapy (i.e., stroma-induced chemoresistance), eventually leading to recurrence. Our goal is to delineate the mechanisms underlying stroma-mediated chemoresistance in AML. We used two human bone marrow stromal cell lines, HS-5 and HS-27A, which are equally effective in protecting AML cells from chemotherapy-induced apop ...[more]

PMID: 25974135

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Project description:IntroductionIn the earliest cases of COVID-19, a higher percentage of severe and fatal cases was observed in patients with cancer, including those with haematological malignancies. However, patients with chronic myeloid leukaemia (CML) had better prognoses, suggesting that tyrosine kinase inhibitors (TKIs) may have a therapeutic effect against SARS-CoV-2. This study describes the clinical and epidemiological characteristics of patients with CML receiving the TKIs tested for SARS-CoV-2 in Tegucigalpa, Honduras.MethodologyAn Analytical cross-sectional study was conducted. The sample included patients with Philadelphia chromosome-positive (Ph+) CML, who had been tested at least once for COVID-19 at the Emma Romero de Callejas Cancer Centre (CCERC). Sociodemographic and clinical variables were both analysed. Epi Info 7.2.4.0 and Stata/MP 16.0 were used to collect and analyse data. The COVID-19 positivity percentage and the association between severity and the TKI used were determined using Fisher's exact test and odds ratio (OR). Data were gathered from clinical records with approval of CCERC institutional management.ResultsOne hundred and forty-nine patients with Ph+ CML were included; 20.1% were COVID-19-positive; 56% were male; mean age was 46 years; 81% were receiving imatinib, with a mean treatment duration of 6 years; 55% achieved a BCR -ABL molecular response ≤ 0.1% (IS). Twenty-one percent had comorbidities. COVID-19 was asymptomatic in 38.7% of patients, mild in 35.5% and severe in 9.7%. One patient died, a fatality rate of 3.2%. No statistical association was found between disease severity and treatment with imatinib versus second-line TKI (OR: 0.833, p: 0.8493, 95% CI: 0.098-10.998).ConclusionDespite high COVID-19 positivity in CML when compared with the literature, this study found a lower fatality rate. The type of TKI used or molecular response at the time of infection was not associated with case severity. Determining the effectiveness of imatinib or other TKIs as a COVID-19 treatment requires randomised clinical trials.

Dataset Information

Stromal CYR61 Confers Resistance to Mitoxantrone via Spleen Tyrosine Kinase Activation in Human Acute Myeloid Leukaemia.

Publications

Stromal CYR61 Confers Resistance to Mitoxantrone via Spleen Tyrosine Kinase Activation in Human Acute Myeloid Leukaemia.

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