ALBERT

Description: This report compares in detail, the role of curcumin treatment in a panel of Burkitt’s lymphoma (BL) cell lines that are either expressing full length Bax with a group of cell lines that are either completely deficient or have decreased expression of Bax. Multiple apoptotic stimuli induce conformational changes in Bax, a pro-apoptotic protein from the Bcl-2 family and its deficiency is a frequent cause of chemo-resistance in a variety of malignancies including Burkitt’s lymphoma. We extent our previous studies on Burkitt’s lymphoma to determine the role of curcumin treatment on BLs. Curcumin (diferuloymethane) is a naturally occurring yellow pigment isolated from the rhizomes of the plant curcuma longa. The medicinal value of curcumin has been well recognized with its anti-oxidant, anti-inflammatory and anti-tumor activities. Curcumin is also known to induce apoptosis in a variety of cancer cells including multiple myeloma and primary effusion lymphomas. To understand the role of Bax in curcumin-induced apoptosis, we used two groups of Burkitt’s lymphoma cell lines, one that expressed the Bax protein (AS283A, KK124 and Pa682PB) and the other group either did not or had decreased expression of Bax (BML895 CA46, and LW878). Cell viability decreased in a dose-dependent manner in AS283A, PA682PB and KK124 with curcumin treatment ranging between 0–40mM whereas only minimal changes in viability was observed in BML895, CA46 and LW878 after treatment. Curcumin induced a dose-dependent apoptosis in the Bax expressing group of cell lines while the cell lines that were either completely deficient or had decreased expression of Bax did not respond to curcumin treatment and remained refractory. In AS283A, KK124, and PA682PB, curcumin induced apoptosis through truncation of BID, loss of mitochondrial potential as determined by JC1 staining with subsequent activation of caspase3 followed by cleavage of PARP. However, in the curcumin resistant cell lines, there was no change in the mitochondrial potential after curcumin treatment and therefore apoptosis did not occur. In addition, zVAD-fmk, a universal inhibitor of caspases prevented caspase3 cleavage as well as cell death in the sensitive cell lines after curcumin treatment suggesting that curcumin-induced apoptosis is caspase dependent. Our findings suggest that Bax integrity is necessary for curcumin to induce apoptosis in Burkitt’s lymphoma cells. These results provide the molecular basis and preliminary data for new treatment strategies that may incorporate curcumin in regimens for Burkitt’s lymphoma treatment.

Description: The last four decades have seen significant increase in the incidence of non-Hodgkin’s lymphoma (NHL) as a possible result of increasing environmental carcinogens exposure. Based on the increasing evidence for the association between carcinogens exposure related cancer risk and xenobiotic gene polymorphisms. We have undertaken a case control study on xenobiotic gene polymorphisms in Saudi individuals with a diagnosis of diffuse large B-cell lymphoma (DLBCL). Polymorphisms in five genes (CYP1A1, GSTT1, GSTP1, GSTM1 and NQO1) were characterized in 187 individuals with DLBCL and 513 normal controls using polymerase chain reaction (PCR) based method. We chose the Saudi population as our study population because of its high consanguinity and its relative genetic homogeneity. The CYP1A1*2C, GSTT1 null and GSTP1 TT genotype were all found to be significant predictors of DLBCL risk (odds ratio 6.62, 11.94 and 3.42 respectively). None of the other alleles tested for proved to be significant indicators of DLBCL risk. These results suggest that the risk of DLBCL may indeed be associated with xenobiotics - metabolism and thus with environmental exposures. Table 1 Distribution of polymorphisms in healthy population and lymphoma patients. Polymorphism Genotype Control group Lymphoma patients p OR CYP1A1 −/− 384(76.5%) 104(78.8%) *2A −/2A 105(20.9%) 24(18.18%) 0.543 0.844 2A/2A 13(2.6%) 3(2.27%) 1.000 0.852 2A allele 13% 11.36% 0.659 0.839 CYP1A1 −/− 443(88.2%) 121(91.66%) *2B −/2B 50(10%) 10(7.58%) 0.505 0.732 2B/2B 9(1.8%) 1(0.76%) 0.697 0.407 2B allele 6.8% 4.55% 0.424 0.646 CYP1A1 −/− 497(99%) 125(94.7%) *2C −/2C 5(1%) 4(3.03%) 0.090 3.181 2C/2C 0 3(2.27%) 0.008 ND 2C allele 0.5% 3.8% 0.011 6.627 NQO1 C609T CC 295 (58.5%) 94 (62.7%) CT 177 (35.1%) 37 (24.7%) 0.051 0.656 TT 32 (6.4%) 19 (8.7%) 0.059 1.863 CT+TT 209 (41.5%) 56 (37.3%) 0.395 0.841 GSTP1 2293 CC 389 (76.3%) 113 (77.9%) CT 113 (22.2%) 24 (16.6%) 0.240 0.731 TT 8 (1.5%) 8 (5.5%) 0.017 3.422 CT+TT 121 (23.7%) 32 (22%) 0.739 0.910 GSTP1 A1578G AA 170 (33.5%) 56 (35%) AG 271 (53.5%) 96 (60%) 0.772 1.075 GG 66 (13%) 8 (5%) 0.013 0.368 AG+GG 337 (66.5%) 104 (65%) 0.774 0.937 GSTT1 P 385 (75%) 36 (20.1%) D 128 (25%) 143 (79.9%)

Description: Although the mechanisms by which all-trans-retinoic acid (RA) regulates gene transcription are well understood, very little is known on the signaling events regulating RA-dependent initiation of mRNA translation. We examined whether the mammalian target of rapamycin (mTOR)/p70 S6 kinase pathway is activated by RA. RA treatment of sensitive cell lines resulted in phosphorylation/activation of mTOR and downstream induction of p70 S6 kinase activity. Such phosphorylation/activation of p70 S6 kinase was inducible in primary acute promyelocytic leukemia (APL) blasts and RA-sensitive NB-4 cells, but was defective in an NB-4 variant cell line (NB-4.007/6) that is resistant to the biologic effects of RA. The RA-dependent activation of p70 S6 kinase was also phosphatidylinositol 3′ kinase (PI3′K)-dependent, and resulted in downstream phosphorylation of the S6 ribosomal protein on Ser235/236 and Ser240/244, events important for initiation of translation for mRNAs with oligopyrimidine tracts in their 5′ untranslated region. RA treatment of leukemia cells also resulted in an mTOR-mediated phosphorylation of the 4E-BP1 repressor of mRNA translation, to induce its deactivation and dissociation from the eukaryotic initiation factor-4E (eIF-4E) complex. Altogether, these findings provide evidence for the existence of a novel RA-activated cellular pathway that regulates cap-dependent translation, and strongly suggest that this cascade plays a role in the induction of retinoid responses in APL cells. (Blood. 2005;105:1669-1677)

Description: Interferon-alpha (IFNα) mediates its biological effects through activation of the JAK-STAT signaling pathway and it has been shown to be one of most effective therapeutic agents for a number of hematological malignancies, including cutaneous T-cell lymphoma (CTCL). Nevertheless, its efficacy is limited by the development of clinical resistance but the reasons for resistance in CTCL are unknown. Here, we report the development of an IFNα-resistant CTCL cell line (HUT78R), characterized by its ability to proliferate in high concentration of recombinant IFNα, which can be used as a model system to study IFN resistance. The levels of IFN receptor expression and binding affinity were found to be comparable between the parental sensitive (HUT78S) and resistant (HUT78R) cells. However, IFNα stimulation failed to induce interferon-stimulated gene factor 3 (ISGF3) complex formation in HUT78R cells. In addition, the expression of the IFN-inducible 2-5 OAS gene was significantly reduced in HUT78R cells, suggesting the presence of a defect in the Jak-STAT signaling pathway. Our results showed that the IFNα-activated form of a latent transcriptional factor STAT1 was not found in HUT78R cells, whereas activated STAT2 and STAT3 were clearly detectable. By Western blotting and reverse transcriptase-polymerase chain reaction (RT-PCR) analyses, we found that HUT78R cells do not express any STAT1 protein or mRNA, suggesting the possibility of a null mutation in the STAT1 gene. Resistance to the growth inhibitory effect of IFNα in CTCL cells may result from lack of STAT1 expression.

Description: All-trans retinoic acid (ATRA) has previously been shown to inhibit the growth of OPM-2 human myeloma cells. The growth inhibition was postulated to result from a transcriptional downregulation of interleukin-6 receptor  (IL-6R) with IL-6Rβ (gp130) unaffected. To formally test this hypothesis, an expression vector designed for constitutive IL-6R expression was constructed and used for transfection of OPM-2 cells. Six stable transfectants were cloned. The expression of IL-6R was shown by immunofluorescence with anti–IL-6R antibody and 125I-IL-6 binding. In five of six transfectant clones, cellular IL-6R was 1.5- to 6-fold higher than the parental cells, with the ligand binding affinity unchanged. While ATRA reduced IL-6R expression in the parental OPM-2 cells, it enhanced its expression in these five transfectants. The clonogenic growth of these transfectants, however, remained strongly inhibited by ATRA. Further analysis, comparing the parental OPM-2 cells and a representative transfectant, clone C5, showed that IL-6 caused rapid tyrosine phosphorylation of gp130 in both OPM-2 and C5 clones. Pretreatment with ATRA greatly reduced IL-6–induced gp130 phosphorylation in OPM-2 cells, reflecting a reduction in cellular IL-6R. In contrast, IL-6–induced gp130 phosphorylation was not reduced by ATRA pretreatment in C5 cells, indicating that the expressed IL-6R was functional. Similar to OPM-2 cells, C5 cells were sensitive to growth inhibition by dexamethasone, which was entirely reversed by exogenous IL-6, suggesting that the IL-6 postreceptor signal transduction remained intact. ATRA was further shown to upregulate p21WAF1 expression and cause dephosphorylation of the retinoblastoma protein (pRB) in both OPM-2 and C5 cells. Exogenous IL-6 also failed to reverse these effects of ATRA. Thus, the growth inhibitory activity of ATRA is not mediated through cellular IL-6R downregulation and is likely to result from a direct upregulation of p21WAF1 and consequent dephosphorylation of pRB.

Description: Phosphatidylinositol 3′-kinase (PI3K) is a key player in cell-growth signaling in a number of lymphoid malignancies, but its role in diffuse large B-cell lymphoma (DLBCL) has not been fully elucidated. Therefore, we investigated the role of the PI3K/AKT pathway in a panel of 5 DLBCL cell lines and 100 clinical samples. Inhibition of PI3K by a specific inhibitor, LY294002, induced apoptosis in SUDHL4, SUDHL5, and SUDHL10 (LY-sensitive) cells, whereas SUDHL8 and OCI-LY19 (LY-resistant) cells were refractory to LY294002-induced apoptosis. AKT was phosphorylated in 5 of 5 DLBCL cell lines and inhibition of PI3K caused dephosphorylation/inactivation of constitutively active AKT, FOXO transcription factor, and GSK3 in LY-sensitive cell lines. In addition, there was a decrease in the expression level of inhibitory apoptotic protein, XIAP, in the DLBCL cell lines sensitive to LY294002 after treatment. However, no effect was observed in XIAP protein levels in the resistant DLBCL cell lines following LY294002 treatment. Finally, using immunohistochemistry, p-AKT was detected in 52% of DLBCL tumors tested. Furthermore, in univariate analysis, high p-AKT expression was associated with short survival. In multivariate analysis, this correlation was no longer significant. Altogether, these results suggest that the PI3K/AKT pathway may be a potential target for therapeutic intervention in DLBCL.

Description: Post-traumatic stress disorder (PTSD) is a highly disabling condition, increasingly recognized as both a disorder of mental health and social burden, but also as an anxiety disorder characterized by fear, stress, and negative alterations in mood. PTSD is associated with structural, metabolic, and molecular changes in several brain regions and the neural circuitry. Brain areas implicated in the traumatic stress response include the amygdala, hippocampus, and prefrontal cortex, which play an essential role in memory function. Abnormalities in these brain areas are hypothesized to underlie symptoms of PTSD and other stress-related psychiatric disorders. Conventional methods of studying PTSD have proven to be insufficient for diagnosis, measurement of treatment efficacy, and monitoring disease progression, and currently, there is no diagnostic biomarker available for PTSD. A deep understanding of cutting-edge neuroimaging genetic approaches is necessary for the development of novel therapeutics and biomarkers to better diagnose and treat the disorder. A current goal is to understand the gene pathways that are associated with PTSD, and how those genes act on the fear/stress circuitry to mediate risk vs. resilience for PTSD. This review article explains the rationale and practical utility of neuroimaging genetics in PTSD and how the resulting information can aid the diagnosis and clinical management of patients with PTSD.

Description: Multiple myeloma (MM) is a hematologic disorder of B lymphocytes characterized by the accumulation of malignant plasma cells (PCs) in the bone marrow. The altered plasma cells overproduce abnormal monoclonal immunoglobulins and also stimulate osteoclasts. The host’s immune system and microenvironment are of paramount importance in the growth of PCs and, thus, in the pathogenesis of the disease. The interaction of MM cells with the bone marrow (BM) microenvironment through soluble factors and cell adhesion molecules causes pathogenesis of the disease through activation of multiple signaling pathways, including NF-κβ, PI3K/AKT and JAK/STAT. These activated pathways play a critical role in the inhibition of apoptosis, sustained proliferation, survival and migration of MM cells. Besides, these pathways also participate in developing resistance against the chemotherapeutic drugs in MM. The imbalance between inflammatory and anti-inflammatory cytokines in MM leads to an increased level of pro-inflammatory cytokines, which in turn play a significant role in dysregulation of signaling pathways and proliferation of MM cells; however, the association appears to be inadequate and needs more research. In this review, we are highlighting the recent findings on the roles of various cytokines and growth factors in the pathogenesis of MM and the potential therapeutic utility of aberrantly activated signaling pathways to manage the MM disease.

Description: Chimeric Antigen Receptor (CAR)-T cell therapy is an exciting development in the field of cancer immunology, wherein immune T-cells from patients are collected, engineered to create ‘CAR’-T cells, and infused back into the same patient. Currently, two CAR-T-cell-based therapies, Tisagenlecleucel and Axicabtagene ciloleucel, are approved by FDA for the treatment of hematological malignancies, acute lymphoblastic leukemia and large B-cell lymphomas. Their approval has been a culmination of several phase I and II clinical studies, which are the subject of discussion in this review article. Over the years, CAR-T cells have evolved to be significantly more persistent in patients’ blood, resulting in a much-improved clinical response and disease remission. This is particularly significant given that the target patient populations of these therapies are those with relapsed and refractory disease who have often progressed on multiple therapies. Despite the promising clinical results, there are still several challenges that need to be addressed. Of particular note are the associated toxicities exemplified by cytokine release syndrome (CRS) and the neurotoxicity. CRS has been addressed by an FDA-approved therapy of its own—tocilizumab. This article focuses on the progress related to CAR-T therapy: the pertinent clinical studies and their major findings, their associated adverse effects, and future perspective.