• BMB Reports
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• 제54권8호
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• pp.431-436
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• 2021

In recent years, restoring anti-tumor immunity has garnered a growing interest in cancer treatment. As potential therapeutics, immune checkpoint inhibitors have demonstrated benefits in many clinical studies. Although various methods have been applied to suppress immune checkpoints to boost anti-tumor immunity, including the use of immune checkpoint inhibitors, there are still unmet clinical needs to improve the response rate of cancer treatment. Here, we show that acetate can suppress the expression of poliovirus receptor (PVR/CD155), a ligand for immune checkpoint, in colon cancer cells. We demonstrated that acetate treatment could enhance effector responses of CD8⁺ T cells by decreasing the expression of PVR/CD155 in cancer cells. We also found that acetate could reduce the expression of PVR/CD155 by deactivating the PI3K/AKT pathway. These results demonstrate that acetate-mediated expression of PVR/CD155 in cancer cells might potentiate the anti-tumor immunity in the microenvironment of cancer. Our findings indicate that maintaining particular acetate concentrations could be a complementary strategy in current cancer treatment.

• Biomolecules & Therapeutics
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• 제26권1호
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• pp.4-9
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• 2018

Cancer metabolism as a field of research was founded almost 100 years ago by Otto Warburg, who described the propensity for cancers to convert glucose to lactate despite the presence of oxygen, which in yeast diminishes glycolytic metabolism known as the Pasteur effect. In the past 20 years, the resurgence of interest in cancer metabolism provided significant insights into processes involved in maintenance metabolism of non-proliferating cells and proliferative metabolism, which is regulated by proto-oncogenes and tumor suppressors in normal proliferating cells. In cancer cells, depending on the driving oncogenic event, metabolism is re-wired for nutrient import, redox homeostasis, protein quality control, and biosynthesis to support cell growth and division. In general, resting cells rely on oxidative metabolism, while proliferating cells rewire metabolism toward glycolysis, which favors many biosynthetic pathways for proliferation. Oncogenes such as MYC, BRAF, KRAS, and PI3K have been documented to rewire metabolism in favor of proliferation. These cell intrinsic mechanisms, however, are insufficient to drive tumorigenesis because immune surveillance continuously seeks to destroy neo-antigenic tumor cells. In this regard, evasion of cancer cells from immunity involves checkpoints that blunt cytotoxic T cells, which are also attenuated by the metabolic tumor microenvironment, which is rich in immuno-modulating metabolites such as lactate, 2-hydroxyglutarate, kynurenine, and the proton (low pH). As such, a full understanding of tumor metabolism requires an appreciation of the convergence of cancer cell intrinsic metabolism and that of the tumor microenvironment including stromal and immune cells.

• Animal cells and systems
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• 제16권3호
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• pp.215-223
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• 2012

Recently it has been reported that immunization with heat-killed tumor cells (HK vaccine) induces anti-tumor immune responses in mice. To investigate how HKvaccine elicits anti-tumor specific adaptive immunity, we examined the effect of HK vaccination on innate immune cells such as dendritic cells (DCs), which are essential for the generation of adaptive immunity. Upon stimulation with HK vaccine, DCs matured to promote not only the upregulation of co-stimulatory molecules but also secretion of cytokine IL12. Furthermore, HK vaccine-treated DCs migrated more efficiently to draining lymph nodes compared with untreated ones. Taken together, HK vaccine can be useful as an adjuvant to activate DCs for anti-tumor immune responses.

• Molecules and Cells
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• 제46권3호
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• pp.142-152
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• 2023

Nuclear factor erythroid 2-related factor 2 (Nrf2) mediates the cellular antioxidant response, allowing adaptation and survival under conditions of oxidative, electrophilic and inflammatory stress, and has a role in metabolism, inflammation and immunity. Activation of Nrf2 provides broad and long-lasting cytoprotection, and is often hijacked by cancer cells, allowing their survival under unfavorable conditions. Moreover, Nrf2 activation in established human tumors is associated with resistance to chemo-, radio-, and immunotherapies. In addition to cancer cells, Nrf2 activation can also occur in tumor-associated macrophages (TAMs) and facilitate an anti-inflammatory, immunosuppressive tumor immune microenvironment (TIME). Several cancer cell-derived metabolites, such as itaconate, L-kynurenine, lactic acid and hyaluronic acid, play an important role in modulating the TIME and tumor-TAMs crosstalk, and have been shown to activate Nrf2. The effects of Nrf2 in TIME are context-depended, and involve multiple mechanisms, including suppression of proinflammatory cytokines, increased expression of programmed cell death ligand 1 (PD-L1), macrophage colony-stimulating factor (M-CSF) and kynureninase, accelerated catabolism of cytotoxic labile heme, and facilitating the metabolic adaptation of TAMs. This understanding presents both challenges and opportunities for strategic targeting of Nrf2 in cancer.

• 대한약학회:학술대회논문집
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• 대한약학회 2002년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2
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• pp.310.2-310.2
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• 2002

Macrophage activated by LPS/IFN-${\gamma}$ playa important role in imflammation. innate immunity and tumor immunity. The recent report has indicated that LPS treated bone marrow macrophages were induced apoptosis. but IFN-${\gamma}$ protects from apoptosis induced by several stimuli in complete medium condition (Jordi et al.. Immunity. Vo1.11. 103-113. 1999). (omitted)

• 대한임상검사과학회지
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• 제54권1호
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• pp.38-48
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• 2022

Carcinoembryonic antigen (CEA)는 다양한 종양에서 발현되는 자가 항원으로 면역치료에서 강력한 표지 인자이며 면역치료를 위한 표적 종양항원으로 널리 알려져 있다. 그러나 수지상세포 단독 치료는 동물모델에서 종양의 발생을 억제하는 데 효과가 있지만 이미 확립된 종양을 제거하는 데는 한계가 있다. 본 연구에서는 항종양 면역 효과를 증가시키기 위하여 화학치료제인 cyclophosphamide (CYP)와 종양 특이 면역치료법인 수지상세포 백신의 병합치료 효과를 CEA를 발현하는 마우스 종양 모델에서 검증하였다. 종양세포 주입 후 2일 소종양군과 10일 대종양군에서 CYP의 항종양 효과를 비교한 결과, 소종양군에서는 100 mg/kg에서 뚜렷한 종양 성장의 억제 효과가 관찰되었지만 대종양군에서는 약한 억제 효과가 관찰되어 본 연구에서는 대종양군을 병합치료의 적합한 모델로 설정하였다. CYP 와 수지상세포 백신의 병합치료(화학면역치료) 시 종양항원 특이 면역반응이 증가되었을 뿐만 아니라 상승적인 항종양 효과가 나타났다. 또한 CYP 치료에서 나타나는 체중 감소 및 조절 T세포와 골수유래 억제세포의 증가에 의한 면역억제는 화학면역치료에 의해 개선되었다. 항원 특이 면역치료를 병합한 화학면역치료가 화학치료의 부작용을 감소시키고 항종양 효과를 증가시킬 수 있는 치료 전략이 될 수 있을 것이다.

• Archives of Pharmacal Research
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• 제9권3호
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• pp.183-187
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• 1986

Some of organophosphate pesticides which are the most heavily used in Korea, were examined for their effects on the murine immune system. Immunotoxicological assay parameters adaopted in this study were Arthus reaction for humoral immunity, delayed type hypersensitivity reaction for cell mediate immunity, carbon clearance for macrophage function and susceptiility to tumor challenge. Subchronic exposure of rodents to the pesticides resulted in the marked suppression of immune functions and enhancement of susceptibility to tumor challenge. Among the pesticides tested (fenitrothion, fenthion, diazinon and EPN), fenitrothion was the most suppressive in Arthus and delayed type hypersensitivity reaction.

• 미생물과산업
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• 제20권3호
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• pp.14-21
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• 1994

Low molecular weight molecules and high molecular weight substances were found to have anti-tumor and immuno-modulating activity. Previously polysaccharides have been received much attention because of adhesives, food additives or animal foods (Whistler et al., 1976). In effort of developing new anti-tumor substances with low toxicity, numerous polysaccharides from yeast, algae, bacteria, higher plants and especially fungi have been investigated for anti-tumor and immuno-modulating activities. Thus the high molecular weight molecule was reported to have anti-tumor activity through host mediated immunity. In this brief article, attention will be paid to polysaccharides which is especially fungal origin.

• Journal of Microbiology and Biotechnology
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• 제16권12호
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• pp.1919-1927
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• 2006

Tumor cells genetically engineered to secrete cytokines are effective in tumor therapy, but various unexpected side effects are observed, which may result from the bulk activation of various bystander cells. In this study, we tested tumor vaccines expressing various membrane-bound forms of IL-2 (mbIL-2) on MethA fibrosarcoma cells to focus antitumor immune responses to CTL. Chimeric forms of IL-2 with whole CD4, deletion forms of CD4, and TNF were expressed on the tumor cell surface, respectively. Tumor clones expressing mbIL-2 or secretory form of IL-2 were able to support the cell growth of CTLL-2, an IL-2-dependent T cell line, and the proliferation of spleen cells from 2C TCR transgenic mice that are responsive to the $p2Ca/L^d$ MHC class I complex. Expression of mbIL-2 on tumor cells reduced the tumorigenicity of tumor cells, and the mice that once rejected the live IL-2/TNF tumor clone acquired systemic immunity against wild-type MethA cells. The IL-2/TNF clone was inferior to other clones in tumor formation, and superior in the stimulation of the CD8+ T cell population in vitro. These results suggest that the IL-2/TNF clone is the best tumor vaccine, and may stimulate CD8+ T cells by direct priming. Expression of IL-2/TNF on tumor cells may serve as an effective gene therapy method to ameliorate the side effects encountered in the recombinant cytokine therapy and the conventional cytokine gene therapy using the secretory form of IL-2.

• 생명과학회지
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• 제16권6호
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• pp.904-910
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• 2006

수지상세포는 종양면역에서 필수적인 강력한 CTL 반응을 개시할 수 있는 유일한 세포이다 . 특히 외인성 종양항원에 대한 CTL 반응 유도는 활성화된 수지상세포의 IL-12 분비를 통한 CD4+ helper T세포의 cross-priming을 필요로 한다. 그러나 최근에 활성화된 수지상세포는 $Th_1$ 면역반응을 유도하지만 활성화 시간이 경과함에 따라 오히려 $Th_2$반응을 유도 할 수 있다. 따라서 본 연구에서는 OVA를 종양항원 모델로 설정하여 종양특이적인 CTL 반응을 형성하기 위한 최적의 수지상세포 활성화 조건을 조사하였다. 마우스 골수세포에 서 수지상세포로의 분화는 항원제시 기능을 위한 표면분자의 발현 측면에서 볼 때 배양 6일-7일 정도가 적합하였다. 수지상세포의 IL-12 생성능은 배양 6일 이상, OVA 항원 탑재 8시간 이상의 경우에 연이은 LPS 성숙자극으로 오히려 감소하는 경향을 보였다. 즉 배양 6일의 수지상세포에 OVA 항원 탑재를 8시간 수행한 경우(8-h DC)가 in vitro에서의 IL-12생성능, ex vivo에서의 세포내 $IFN-{\gamma}$를 발현하는 CD8+ T세포의 증가 및 OVA 특이적인 세포독성효과 등에서 가장 좋은 결과를 보였다. 또한 in vivo에서 종양 치료 및 예방효과에서도 8-h DC로 면역한 경우에 가장 우수한 종양형성 억제 효과와 생존기간 연장효과를 보였다. 현재 대부분의 수지상 세포를 이용한 항종양 백신에서 항원 탑재반응을 24시간 동안 수행하고 있으나, 본 실험의 결과로 볼 때, 8시간의 in vitro 항원 탑재가 보다 효과적인 종양특이적 CTL 반응과 항종양 면역반응을 유도함을 알 수 있다. 결론적으로 본 연구를 통하여 8시간 이상의 항원접촉은 수지상세포의 기능적 활성능력을 오히려 고갈시킬 수 있음을 제시한다.