Overexpression of the CXCR4 receptor is a hallmark of chronic lymphocytic leukemia (CLL) and is important for CLL cell survival, migration, and interaction with their protective microenvironment. In acute myelogenous leukemia (AML), PIM1 was shown to regulate the surface expression of the CXCR4 receptor. Here, we show that PIM (proviral integration site for Moloney murine leukemia virus) kinases 1-3 are overexpressed and that the CXCR4 receptor is hyperphosphorylated on Ser339 in CLL compared with normal lymphocytes. Furthermore, CXCR4 phosphorylation correlates with PIM1 protein expression and PIM1 transcript levels in CLL. PIM kinase inhibition with three different PIM kinase inhibitors induced apoptosis in CLL cells independent of the presence of protective stromal cells. In addition, PIM inhibition caused dephosphorylation of the CXCR4 receptor on Ser339, resulting in enhanced ligand-dependent CXCR4 internalization and reduced re-externalization after withdrawal of CXCL12. Furthermore, PIM inhibition in CLL cells blocked CXCR4 functions, such as migration toward CXCL12-or CXCL12-induced extracellular signal-regulated kinase (ERK) phosphorylation. In concordance, pretreatment of CLL cells with PIM kinase inhibitors strongly reduced homing of CLL cells toward the bone marrow and the spleen of Rag2
Inhibition of central nervous system sodium pump with ouabain produces a plausible animal model of mania. This model may be useful for preclinical screening of potential mood stabilizers.
BackgroundIntermittent preventive treatment in pregnancy (IPTp) with sulfadoxine–pyrimethamine (SP) is widely implemented in sub-Saharan Africa for the prevention of malaria in pregnancy and adverse birth outcomes. However, in areas of intense SP resistance, the efficacy of IPTp may be compromised.MethodsA cross-sectional study among 915 delivering women (728 analysable live singleton deliveries) was conducted in Fort Portal, western Uganda, to assess associations of reported IPTp use, Plasmodium falciparum infection, maternal anaemia, low birth weight, and preterm delivery, and to estimate the degree of SP resistance as reflected by pfdhfr/pfdhps mutations.ResultsPlasmodium falciparum infection was detected by PCR in 8.9 % and by microscopy of placental blood samples in 4.0 %. Infection was significantly associated with stillbirth, early neonatal death, anaemia, low birth weight, and pre-term delivery. Eighty percent of the women had taken at least one dose of IPTp, and more than half had taken two doses. As compared to women without chemoprophylaxis against malaria, IPTp had no significant influence on the presence of P. falciparum infection (13.8 vs. 9.6 %, P = 0.31). Nor was it associated with reductions in anaemia, low birth weight or preterm delivery. P. falciparum with intense SP resistance (pfdhfr/pfdhps quintuple or sextuple mutations) were observed in 93 % (pfdhps 581G, 36 %), and the additional high resistance allele pfhdr 164L in 36 %.ConclusionsIn Fort Portal, Uganda, reported use of IPTp with SP does not provide an observable benefit. The molecular markers of P. falciparum indicate high grade SP resistance reaching the threshold set by WHO for the discontinuation of IPTp with SP. Alternative approaches for the prevention of malaria in pregnancy are urgently needed.
Since 2012, lifelong antiretroviral therapy for all HIV-positive pregnant women ("Option B+") is recommended by WHO for the prevention of mother-to-child transmission of HIV (PMTCT). Many sub-Saharan African countries have since introduced this regimen, but to date, longer-term outcome evaluations are scarce. We conducted an observational study in Fort Portal Municipality, Uganda, to describe uptake and adherence of Option B+ during pregnancy. HIV-positive women approaching antenatal care (ANC) services in two hospitals were enrolled and followed-up at monthly routine ANC visits until delivery. At each visit, next to sociodemographic and clinical data, we assessed drug adherence through pill counts. In total, 124 HIV-positive pregnant women were enrolled in our study; from these, 80.8% had not been aware of their positive serostatus before. Forty-five PMTCT clients (36.3%) never returned to ANC after their first visit. Protective factors (p < 0.05) for immediate loss to care included previous HIV status knowledge, status disclosure before or at first ANC visit, and tertiary education. Among those clients starting Option B+, the median adherence during pregnancy was 95.7% pill intake. Rather low adherence (<80%) was observed in 21.1% of clients, while more than half achieved an adherence level of ≥95%, with 40.8% of all clients being 100% adherent. The cohort's median adherence remained stable throughout the course of pregnancy. Healthcare providers should place high emphasis on individual PMTCT counseling at first ANC encounter, and pay special attention to those women previously unaware of their HIV status. However, after initial uptake, high adherence seems to be feasible for Option B+.
Cell adhesion-mediated drug resistance (CAM-DR) by the bone marrow (BM) is fundamental to multiple myeloma (MM) propagation and survival. Targeting BM protection to increase the efficacy of current anti-myeloma treatment has not been extensively pursued. To extend the understanding of CAM-DR, we hypothesized that the cytotoxic effects of novel anti-myeloma agents may be abrogated by the presence of BM stroma cells (BMSCs) and restored by addition of the CXCL12 antagonist NOX-A12 or the CXCR4 inhibitor plerixafor. Following this hypothesis, we evaluated different anti-myeloma agents alone, with BMSCs and when combined with plerixafor or NOX-A12. We verified CXCR4, CD49d (also termed ITGA4) and CD44 as essential mediators of BM adhesion on MM cells. Additionally, we show that CXCR7, the second receptor of stromal-derived-factor-1 (CXCL12), is highly expressed in active MM. Co-culture proved that co-treatment with plerixafor or NOX-A12, the latter inhibiting CXCR4 and CXCR7, functionally interfered with MM chemotaxis to the BM. This led to the resensitization of MM cells to the anti-myeloma agents vorinostat and pomalidomide and both proteasome inhibitors bortezomib and carfilzomib. Within a multicentre phase I/II study, NOX-A12 was tested in combination with bortezomib-dexamethasone, underlining the feasibility of NOX-A12 as an active add-on agent to antagonize myeloma CAM-DR.
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