• IMMUNE NETWORK
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• 제22권1호
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• pp.10.1-10.17
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• 2022

Systemic autoimmune diseases arise from loss of self-tolerance and immune homeostasis between effector and regulator functions. There are many therapeutic modalities for autoimmune diseases ranging from conventional disease-modifying anti-rheumatic drugs and immunosuppressants exerting nonspecific immune suppression to targeted agents including biologic agents and small molecule inhibitors aiming at specific cytokines and intracellular signal pathways. However, such current therapeutic strategies can rarely induce recovery of immune tolerance in autoimmune disease patients. To overcome limitations of conventional treatment modalities, novel approaches using specific cell populations with immune-regulatory properties have been attempted to attenuate autoimmunity. Recently progressed biotechnologies enable sufficient in vitro expansion and proper manipulation of such 'tolerogenic' cell populations to be considered for clinical application. We introduce 3 representative cell types with immunosuppressive features, including mesenchymal stromal cells, Tregs, and myeloid-derived suppressor cells. Their cellular definitions, characteristics, mechanisms of immune regulation, and recent data about preclinical and clinical studies in systemic autoimmune diseases are reviewed here. Challenges and limitations of each cell therapy are also addressed.

• Tuberculosis and Respiratory Diseases
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• 제87권1호
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• pp.22-30
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• 2024

Tumor immune evasion is a complex process that involves various mechanisms, such as antigen recognition restriction, immune system suppression, and T cell exhaustion. The tumor microenvironment contains various immune cells involved in immune evasion. Recent studies have demonstrated that granulocyte colony-stimulating factor (G-CSF) and granulocyte-macrophage colony-stimulating factor (GM-CSF) induce immune evasion in lung cancer by modulating neutrophils and myeloid-derived suppressor cells. Here we describe the origin and function of G-CSF and GM-CSF, particularly their role in immune evasion in lung cancer. In addition, their effects on programmed death-ligand 1 expression and clinical implications are discussed.

• Molecular & Cellular Toxicology
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• 제2권3호
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• pp.159-165
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• 2006

To determine the anticancer effect of D-amygdalin (D-mandelinitrole-${\beta}$-D-gentiobioside) in human chronic myeloid leukemia cells K562, we profiled the gene expression between amygdalin treatment and control groups. Through 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay, the cytotoxicity of D-amygdalin was $57.79{\pm}1.83%$ at the concentration of 5 mg/mL for 24 h. We performed cDNA microarray analysis and compared the gene expression profiles between D-amygdalin (5 mg/mL, 24 h) treatment and control groups. Among the genes changed by D-amygdalin, we paid attention to cell cycle-related genes, and particularly cell cycle regulator genes; because arrest of cell cycle processing was ideal tactic in remedy for cancer. In our data, expressions of cyclin-dependent kinase inhibitor 1B (p27, Kip1) (CDKN1B), ataxia telangiectasia mutated (includes complementation groups A, C, and D) (ATM), cyclin-dependent kinase inhibitor 1C (p57, Kip2) (CDKN1C), and CHK1 checkpoint homolog (CHEK1, formally known as CHK1) were increased, while expressions of cyclin-dependent kinase 2 (CDK2), cell division cycle 25A (CDC25A), and cyclin E1 (CCNE1) were decreased. The pattern of these gene expressions were confirmed through RT-PCR. Our results showed that D-amygdalin might control cell cycle regulator genes and arrest S phase of cell cycle in K562 cells as the useful anticancer drug.

• Biomolecules & Therapeutics
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• 제32권5호
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• pp.582-600
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• 2024

Tyrosine kinase inhibitors (TKIs) have revolutionized the treatment landscape for chronic myeloid leukemia (CML). However, TKI resistance poses a significant challenge, leading to treatment failure and disease progression. Resistance mechanisms include both BCR::ABL1-dependent and BCR::ABL1-independent pathways. The mechanisms underlying BCR::ABL1 independence remain incompletely understood, with CML cells potentially activating alternative signaling pathways, including the AKT/mTOR and JAK2/STAT5 pathways, to compensate for the loss of BCR::ABL1 kinase activity. This study explored tumoral VISTA (encoded by VSIR) as a contributing factor to TKI resistance in CML patients and identified elevated tumoral VISTA levels as a marker of resistance and poor survival. Through in vitro and in vivo analyses, we demonstrated that VSIR knockdown and the application of NSC-622608, a novel VISTA inhibitor, significantly impeded CML cell proliferation and induced apoptosis by attenuating the AKT/mTOR and JAK2/STAT5 pathways, which are crucial for CML cell survival independent of BCR::ABL1 kinase activity. Moreover, VSIR overexpression promoted TKI resistance in CML cells. Importantly, the synergistic effect of NSC-622608 with TKIs offers a potent therapeutic avenue against both imatinib-sensitive and imatinib-resistant CML cells, including those harboring the challenging T315I mutation. Our findings highlight the role of tumoral VISTA in mediating TKI resistance in CML, suggesting that inhibition of VISTA, particularly in combination with TKIs, is an innovative approach to enhancing treatment outcomes in CML patients, irrespective of BCR::ABL1 mutation status. This study not only identified a new pathway contributing to TKI resistance but also revealed the possibility of targeting tumoral VISTA as a means of overcoming this significant clinical challenge.

• Molecules and Cells
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• 제37권1호
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• pp.66-73
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• 2014

Myeloid-derived suppressor cells (MDSCs) play an important role in impairing the function of T cells. We characterized MDSCs in two chronic hepatitis C (CHC) cohorts: a cross-sectional group that included 61 treatment-naive patients with CHC, 14 rapid virologic response (RVR) cases and 22 early virologic response (EVR) cases; and a longitudinal group of 13 cases of RVR and 10 cases of EVR after pegylated-interferon-${\alpha}$/ribavirin treatment for genotype 1b HCV infection. Liver samples from 32 CHC patients and six healthy controls were subjected to immunohistochemical analysis. MDSCs frequency in treatment-naive CHC was significantly higher than in RVR, EVR, or healthy subjects and was positively correlated with HCV RNA. Patients infected with HCV genotype 2a had a significantly higher frequency of MDSCs than those infected with genotype 1b. Decreased T cell receptor (TCR) ${\zeta}$ expression on $CD8^+$ T cells was significantly associated with an increased frequency of MDSCs in treatment-naive CHC patients and was restored by L-arginine treatment in vitro. Increased numbers of liver arginase-$1^+$ cells were closely associated with the histological activity index in CHC. The TCR ${\zeta}$ chain was significantly downregulated on hepatic $CD8^+$ T cells in CHC. During antiviral follow up, MDSCs frequency in peripheral blood mononuclear cells was directly correlated with the HCV RNA load in the plasma and inversely correlated with TCR ${\zeta}$ chain expression in $CD8^+$ T cells in both RVR and EVR cases. Notably, the RVR group had a higher frequency of MDSCs at baseline than the EVR group. Collectively, this study provides evidence that MDSCs might be associated with HCV persistence and downregulation of CD8 ${\zeta}$ chain expression.

• BMB Reports
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• 제48권12호
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• pp.691-695
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• 2015

We report that phytosphingosine, a sphingolipid found in many organisms and implicated in cellular signaling, promotes megakaryocytic differentiation of myeloid leukemia cells. Specifically, phytosphingosine induced several hallmark changes associated with megakaryopoiesis from K562 and HEL cells including cell cycle arrest, cell size increase and polyploidization. We also confirmed that cell type specific markers of megakaryocytes, CD41a and CD42b are induced by phytosphingosine. Phospholipids with highly similar structures were unable to induce similar changes, indicating that the activity of phytosphingosine is highly specific. Although phytosphingosine is known to activate p38 mitogen-activated protein kinase (MAPK)-mediated apoptosis, the signaling mechanisms involved in megakaryopoiesis appear to be distinct. In sum, we present another model for dissecting molecular details of megakaryocytic differentiation which in large part remains obscure.

• Oncology Letters
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• 제42권5호
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• pp.2149-2158
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• 2019

Primary refractory acute myeloid leukemia (AML) and early recurrence of leukemic cells are among the most difficult hurdles to overcome in the treatment of AML. Moreover, uncertainties surrounding the molecular mechanism underlying refractory AML pose a challenge when it comes to developing novel therapeutic drugs. However, accumulating evidence suggests a contribution of phosphatase and tensin homolog (PTEN)/protein kinase B (AKT) signaling to the development of refractory AML. To assess PTEN/AKT signaling in AML, two types of AML cell lines were evaluated, namely control HL60 cells and KG1α cells, a refractory AML cell line that is resistant to idarubicin and cytarabine (AraC) treatment. Changes in the expression level of glycolysis- and mitochondrial oxidative phosphorylation-related genes and proteins were evaluated by reverse transcription-quantitative polymerase chain reaction and western blot analyses, respectively. The mitochondrial oxygen consumption and extracellular acidification rates were measured using an XF24 analyzer. CCK8 assay and Annexin V/PI staining were used to analyze cell viability and cellular apoptosis, respectively. The PTEN protein was found to be depleted, whereas AKT phosphorylation levels were elevated in KG1α cells compared with HL60 cells. These changes were associated with increased expression of glucose transporter 1 and hexokinase 2, and increased lactate production. AKT inhibition decreased the proliferation of KG1α cells and decreased extracellular acidification without affecting HL60 cells. Notably, AKT inhibition increased the susceptibility of KG1α cells to chemotherapy with idarubicin and AraC. Taken together, the findings of the present study indicate that activation of AKT by PTEN deficiency sustains the refractory AML status through enhancement of glycolysis and mitochondrial respiration, effects that may be rescued by inhibiting AKT activity.

• 대한의생명과학회지
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• 제19권2호
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• pp.118-123
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• 2013

Tumor necrosis factor-alpha (TNF-${\alpha}$) is a proinflammatory cytokine that mediates the inflammatory response and immune functions, and modulates the proliferation, differentiation and cell death of cancer cells. The differential functions of TNF-${\alpha}$ in various human cells due to the formation of different stimulating pathway upon the binding of TNF-${\alpha}$ to its receptors. In the present study, we examined the different effects of TNF-${\alpha}$ on the survival and apoptosis between normal granulocytes and human myeloid leukemia HL-60 cells. Although TNF-${\alpha}$ did not affect on the constitutive apoptosis of granulocytes, TNF-${\alpha}$ strongly induced the apoptosis of HL-60 cells in a dose- and a time-dependent manner. TNF-${\alpha}$-induced apoptosis was occurred via the activation of caspase 8, caspase 9 and caspase 3/7 and the induction of ROS production in HL-60 cells. Also, BAY-11-7085, a NF-${\kappa}B$ inhibitor, blocked the TNF-${\alpha}$-induced apoptosis in HL-60 cells. NF-${\kappa}B$ may be involved in TNF-${\alpha}$-induced apoptotic signaling pathway in HL-60 cells. These results suggest that TNF-${\alpha}$ activates apoptotic pathways and its process depends on cell type and many cellular factors. A better understanding of the differential effect of TNF-${\alpha}$ on cell apoptosis and survival may provide important information that can be used to elucidate the specific inhibitory effect of TNF-${\alpha}$ on the cancer dis.

• Tuberculosis and Respiratory Diseases
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• 제62권4호
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• pp.290-298
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• 2007

연구배경: 흉수는 다양한 원인에 의하여 생성되며 임상적으로 여출액과 삼출액으로 구분하게 되며 삼출액일 경우에는 그 원인 질환들을 감별해야 하나 적용할 만한 표지자가 많지 않다. Soluble Triggering Receptor Expressed on Myeloid cells(sTREM-1)는 면역글로블린의 일종으로 세균이나 진균 감염에서 증가된다고 보고되어 있으며 활성화된 탐식세포에서 떨어져 나와 체액에서도 수용성 상태로 발견될 수 있다. 저자들은 흉수에서 sTREM-1의 측정이 흉수의 감별 진단에 유용한지와 감염성 질환에 의한 흉수에 대한 표지자로서 유용한지에 대한 가능성을 알아보고자 하였다. 대상 및 방법: 2004년 3월부터 2005년 12월까지 흉수를 주소로 내원한 환자들에서 흉수의 세포 수 및 백혈구 분획, 생화학적 검사(pH, protein, LDH, glucose), 세포진 검사, ADA, 미생물학적 검사 결과 이외에 sTREM-1을 측정하였다. 대상환자는 48명으로 남:여 각각 27:21명이었고, 평균 연령은 59세였다. 최종 진단은 암성 흉수는 13명, 결핵성 흉수는 14명, 부폐렴성 흉수는 17명, 여출성 흉수는 4명이었다. 결과: 흉수의 sTREM-1은 부폐렴성 흉수에서 $344.0{\pm}488.7pg/mL$로 결핵성 흉수($81.7{\pm}56.6pg/mL$)와 악성 흉수($39.3{\pm}19.6pg/mL$)보다 높게 측정되었다. 부폐렴성 흉수에 대한 sTREM-1의 ROC 곡선 결과 55.4 pg/mL에서 민감도와 특이도가 각각 70.6%와 74.1%로 측정되었다. 또한 흉수 sTREM-1은 흉수의 호중구수, 흉수 LDH, 흉수/혈청 LDH, 흉수 ADA와 유의한 상관관계를 보였다. 결론: 흉수의 sTREM-1은 부폐렴성 흉수에서 다른 원인의 흉수에서보다 유의하게 상승되어 부폐렴성 흉수의 표지자로서 유용하였으며 기존의 진단 표지자에 더하여 흉수의 감별진단에 유용할 것으로 생각된다.

• Biomolecules & Therapeutics
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• 제30권6호
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• pp.553-561
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• 2022

Chronic myeloid leukemia (CML) is a slowly progressing hematopoietic cell disorder. Sphingosine kinase 1 (SPHK1) plays established roles in tumor initiation, progression, and chemotherapy resistance in a wide range of cancers, including leukemia. However, small-molecule inhibitors targeting SPHK1 in CML still need to be developed. This study revealed the role of SPHK1 in CML and investigated the potential anti-leukemic activity of hirsuteine (HST), an indole alkaloid obtained from the oriental plant Uncaria rhynchophylla, in CML cells. These results suggest that SPHK1 is highly expressed in CML cells and that overexpression of SPHK1 represents poor clinical outcomes in CML patients. HST exposure led to G2/M phase arrest, cellular apoptosis, and downregulation of Cyclin B1 and CDC2 and cleavage of Caspase 3 and PARP in CML cells. HST shifted sphingolipid rheostat from sphingosine 1-phosphate (S1P) towards the ceramide coupled with a marked inhibition of SPHK1. Mechanistically, HST significantly blocked SPHK1/S1P/S1PR1 and BCR-ABL/PI3K/Akt pathways. In addition, HST can be docked with residues of SPHK1 and shifts the SPHK1 melting curve, indicating the potential protein-ligand interactions between SPHK1 and HST in both CML cells. SPHK1 overexpression impaired apoptosis and proliferation of CML cells induced by HST alone. These results suggest that HST, which may serve as a novel and specific SPHK1 inhibitor, exerts anti-leukemic activity by inhibiting the SPHK1/S1P/S1PR1 and BCR-ABL/PI3K/Akt pathways in CML cells, thus conferring HST as a promising anti-leukemic drug for CML therapy in the future.