• Asian Pacific Journal of Cancer Prevention
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• v.14 no.2
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• pp.631-637
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• 2013

Luteolin is a naturally occurring flavonoid present in many plants with diverse applications in pharmacology. Despite several studies elucidating its significant anti-cancer activity against various cancer cells, the mechanism of action in skin cancer is not well addressed. Hence, we investigated the effects of luteolin in HaCaT (human immortalized keratinocytes) and A375 (human melanoma) cells. The radical scavenging abilities of luteolin were determined spectrophotometrically, prior to a cytotoxic study (XTT assay). Inhibitory effects were assessed by colony formation assay. Further, the capability of luteolin to induce cell cycle arrest and apoptosis were demonstrated by flow cytometry and cellular DNA fragmentation ELISA, respectively. The results revealed that luteolin possesses considerable cytotoxicity against both HaCaT and A375 cells with $IC_{50}$ values of 37.1 ${\mu}M$ and 115.1 ${\mu}M$, respectively. Luteolin also inhibited colony formation and induced apoptosis in a dose and time-dependent manner by disturbing cellular integrity as evident from morphological evaluation by Wright-Giemsa staining. Accumulation of cells in G2/M (0.83-8.14%) phase for HaCaT cells and G0/G1 (60.4-72.6%) phase for A375 cells after 24 h treatment indicated cell cycle arresting potential of this flavonoid. These data suggest that luteolin inhibits cell proliferation and promotes cell cycle arrest and apoptosis in skin cancer cells with possible involvement of programmed cell death, providing a substantial basis for it to be developed into a potent chemopreventive template for skin cancer.

• BMB Reports
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• v.57 no.6
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• pp.287-292
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• 2024

Hepatocellular Carcinoma (HCC), the predominant primary hepatic malignancy, is the prime contributor to mortality. Despite the availability of multiple surgical interventions, patient outcomes remain suboptimal. Immunotherapies have emerged as effective strategies for HCC treatment with multiple clinical advantages. However, their curative efficacy is not always satisfactory, limited by the dysfunctional T cell status. Thus, there is a pressing need to discover novel potential biomarkers indicative of T cell exhaustion (Tex) for personalized immunotherapies. One promising target is Cyclin-dependent kinase inhibitor 2 (CDKN2) gene, a key cell cycle regulator with aberrant expression in HCC. However, its specific involvement remains unclear. Herein, we assessed the potential of CDKN2 expression as a promising biomarker for HCC progression, particularly for exhausted T cells. Our transcriptome analysis of CDKN2 in HCC revealed its significant role involving in HCC development. Remarkably, single-cell transcriptomic analysis revealed a notable correlation between CDKN2 expression, particularly CDKN2A, and Tex markers, which was further validated by a human cohort study using human HCC tissue microarray, highlighting CDKN2 expression as a potential biomarker for Tex within the intricate landscape of HCC progression. These findings provide novel perspectives that hold promise for addressing the unmet therapeutic need within HCC treatment.

• Animal cells and systems
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• v.8 no.2
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• pp.125-133
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• 2004

We have extended our previous work that cross-linking CD4 molecules using specific MAb induced antigen nonspecific, MHC unrestricted killing of virally infected target cells by CD$4^+$We have extended our previous work that cross-linking CD$4^+$ molecules using specific MAb induced antigen nonspecific, MHC unrestricted killing of virally infected target cells by CD$4^+$ T cells. The killing activity of antibody activated CD$4^+$T cells was completely blocked by herbimycin A, a protein tyrosine kinase (PTK) inhibitor, but not by bisindolylamaleimide, a protein kinase C (PKC) inhibitor. Herbimycin A treated human or bovine peripheral blood CD$4^+$T cells lacked PTK activity and failed to kill virally infected target cells even after cross-linking of CD4 molecules. The CD$4^+$cross-linking failed to induce effector cell proliferation or the transcription of TNF${\beta}$ Upregulation of TNF${\beta}$ was induced by incubating the antibody activated effector cells with BHV-1 infected D17 target cells for 10 h. Anti-TNF${\beta}$ antibody partially abolished (13-44%) the direct effector cell-mediated antiviral cytotoxicity. However, this antibody neutralized 70 to 100% of antiviral activity of effector and target cell culture supernatants against BHV-1 infected D17 cells. The inhibition level of the antiviral activity by the antibody was dependent on the effector and target cell ratio. These results support the hypothesis that increased p$56^ICK enzyme activity in effector cells transduces a signal critical for effector cell recognition of viral glycoproteins expressed on the target cells. Following target cell recognition, lytic cytokines known to participate in target cell killing were produced. A better understanding of the killing activity displayed by CD$4^+$T lymphocytes following surface receptor cross-linking will provide insight into the mechanisms of cytotoxic activity directed toward virally-infected cells.T cells. The killing activity of antibody activated CD$4^+$T cells was completely blocked by herbimycin A, a protein tyrosine kinase (PTK) inhibitor, but not by bisindolylamaleimide, a protein kinase C (PKC) inhibitor. Herbimycin A treated human or bovine peripheral blood CD4T cells lacked PTK activity and failed to kill virally infected target cells even after cross-linking of CD4molecules. The CD4 cross-linking failed to induce effector cell proliferation or the transcription of TNF$\beta$. Upregulation of TNF$\beta$ was induced by incubating the antibody activated effector cells with BHV-1 infected D17 target cells for 10 h. Anti-TNF$\beta$ antibody partially abolished (13-44%) the direct effector cell-mediated antiviral cytotoxicity. However, this antibody neutralized 70 to 100% of antiviral activity of effector and target cell culture supernatants against BHV-1 infected D17 cells. The inhibition level of the antiviral activity by the antibody was dependent on the effector and target cell ratio. These results support the hypothesis that increased $56^ICK enzyme activity in effector cells transduces a signal critical for effector cell recognition of viral glycoproteins expressed on the target cells. Following target cell recognition, lytic cytokines known to participate in target cell killing were produced. A better understanding of the killing activity displayed by CD$4^+$T lymphocytes following surface receptor cross-linking will provide insight into the mechanisms of cytotoxic activity directed toward virally-infected cells.

• Restorative Dentistry and Endodontics
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• v.35 no.6
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• pp.473-478
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• 2010

Objectives: This study was performed to investigate the biocompatibility of newly introduced Bioaggregate on human pulp and PDL cells. Materials and Methods: Cells were collected from human pulp and PDL tissue of extracted premolars. Cell culture plate was coated either with Bioaggregate or white MTA, then the same number of cells were poured to cell culture dishes. Cell attachment and growth was examined under a phase microscope after 1,3 and 7 days of seeding. Cell viability was measured and the data was analyzed using Student t-test and one way ANOVA. Results: Both types of cells used in this study were well attached and grew healthy on Bioaggregate and MTA coated culture dishes. No cell inhibition zone was observed in Bioaggregate group. There was no statistical difference of viable cells between bioaggreagte and MTA groups. Conclusions: Bioaggregate appeared to be biocompatible compared with white MTA on human pulp and PDL cells.

• IMMUNE NETWORK
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• v.15 no.4
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• pp.199-205
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• 2015

T-bet is a critical transcription factor that regulates differentiation of Th1 cells from $CD4^+$ precursor cells. Since T-bet directly binds to the promoter of the IFN-${\gamma}$ gene and activates its transcription, T-bet deficiency impairs IFN-${\gamma}$ production in Th1 cells. Interestingly, T-bet-deficient Th cells also display substantially augmented the production of IL-2, a T cell growth factor. Exogenous expression of T-bet in T-bet deficient Th cells rescued the IFN-${\gamma}$ production and suppressed IL-2 expression. IFN-${\gamma}$ and IL-2 reciprocally regulate Th cell proliferation following TCR stimulation. Therefore, we examined the effect of T-bet on Th cell proliferation and found that T-bet deficiency significantly enhanced Th cell proliferation under non-skewing, Th1-skewing, and Th2-skewing conditions. By using IFN-${\gamma}$-null mice to eliminate the anti-proliferative effect of IFN-${\gamma}$, T-bet deficiency still enhanced Th cell proliferation under both Th1- and Th2-skewing conditions. Since the anti-proliferative activity of T-bet may be influenced by IL-2 suppression in Th cells, we examined whether T-bet modulates IL-2-independent cell proliferation in a non-T cell population. We demonstrated that T-bet expression induced by ecdysone treatment in human embryonic kidney (HEK) cells increased IFN-${\gamma}$ promoter activity in a dose dependent manner, and sustained T-bet expression considerably decreased cell proliferation in HEK cells. Although the molecular mechanisms underlying anti-proliferative activity of T-bet remain to be elucidated, T-bet may directly suppress cell proliferation in an IFN-${\gamma}$- or an IL-2-independent manner.

• Journal of Physiology & Pathology in Korean Medicine
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• v.16 no.4
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• pp.693-700
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• 2002

SCRT (Sochungyong-tang) has been used for immune disease in human. The purpose of this study was effect of Helper T cell, major regulator of immune system. Spleen cell from 8 week BALB/c mice were cultured in SCRT containing medium without activation for 48 h. The MTS assay and flow cytometry revealed that SCRT treated Iympocyte were non-effect in percentage of CD4+ T cell. Subsequently CD4+ T cell were isolated and cultured in SCRT containing medium. SCRT were non-effective on CD4+ T cell without any involvement of APC. In order to evaluate the direct effect of SCRT on Helper T cell, CD4+ T cell isolated after 48 h of culture in SCRT containing medium and activated with and without anti-CD3/anti-CD28 activation for 48 h. A lower level of CD69 was observed in SCRT treated cells in flow cytometry analysis. Subsequently Using RT-PCR analysis the expression of mRNA for IL-2, INF-γ are upregulated and, IL-4 is downregulated in CD4 T cell. The result suggests that SCRT makes Th1 significantly increased and Th2 relatively inhibited. The results suggest that SCRT potentiate Th1 cell and decrease Th2 development at the same time, which is believed to be bemeficial for IgE-mediated responses.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.15
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• pp.6581-6589
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• 2015

Background: Previously, stingless bee (Trigona spp.) products from East Kalimantan, Indonesia, were successfully screened for in vitro antiproliferative activity against human cancer derived cell lines. It was established that propolis from T. incisa presented the highest in vitro cytotoxicity against the SW620 colon cancer cell line (6% cell survival in $20{\mu}g/mL$). Materials and Methods: Propolis from T. incisa was extracted with methanol and further partitioned with n-hexane, ethyl acetate and methanol. The in vitro cytotoxicity of the extracts was assessed by the MTT assay against human colon (SW620), liver (Hep-G2), gastric (KATO-III), lung (Chago) and breast (BT474) cancer derived cell lines. The active fractions were further enriched by silica gel quick column, absorption and size exclusion chromatography. The purity of each fraction was checked by thin layer chromatography. Cytotoxicity in BT-474 cells induced by cardanol compared to doxorubicin were evaluated by MTT assay, induction of cell cycle arrest and cell death by flow cytometric analysis of propidium iodide and annexin-V stained cells. Results: A cardol isomer was found to be the major compound in one active fraction (F45) of T. incisa propolis, with a cytotoxicity against the SW620 ($IC_{50}$ of $4.51{\pm}0.76{\mu}g/mL$), KATO-III (IC50 of $6.06{\pm}0.39{\mu}g/mL$), Hep-G2 ($IC_{50}$ of $0.71{\pm}0.22{\mu}g/mL$), Chago I ($IC_{50}$ of $0.81{\pm}0.18{\mu}g/mL$) and BT474 (IC50 of $4.28{\pm}0.14{\mu}g/mL$) cell lines. Early apoptosis (programmed cell death) of SW620 cells was induced by the cardol containing F45 fraction at the $IC_{50}$ and $IC_{80}$ concentrations, respectively, within 2-6 h of incubation. In addition, the F45 fraction induced cell cycle arrest at the G1 subphase. Conclusions: Indonesian stingless bee (T. incisa) propolis had moderately potent in vitro anticancer activity on human cancer derived cell lines. Cardol or 5-pentadecyl resorcinol was identified as a major active compound and induced apoptosis in SW620 cells in an early period (${\leq}6h$) and cell cycle arrest at the G1 subphase. Thus, cardol is a potential candidate for cancer chemotherapy.

• Molecules and Cells
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• v.38 no.10
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• pp.918-924
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• 2015

During T cell activation, mitochondrial content increases to meet the high energy demand of rapid cell proliferation. With this increase, the level of reactive oxygen species (ROS) also increases and causes the rapid apoptotic death of activated cells, thereby facilitating T cell homeostasis. Nicotinamide (NAM) has previously been shown to enhance mitochondria quality and extend the replicative life span of human fibroblasts. In this study, we examined the effect of NAM on $CD8^+$ T cell activation. NAM treatment attenuated the increase of mitochondrial content and ROS in T cells activated by CD3/CD28 antibodies. This was accompanied by an accelerated and higher-level clonal expansion resulting from attenuated apoptotic death but not increased division of the activated cells. Attenuation of ROS-triggered pro-apoptotic events and upregulation of Bcl-2 expression appeared to be involved. Although cells activated in the presence of NAM exhibited compromised cytokine gene expression, our results suggest a means to augment the size of T cell expansion during activation without consuming their limited replicative potential.

• Journal of Periodontal and Implant Science
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• v.33 no.2
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• pp.179-191
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• 2003

Since periodontal infections are suggested as risk factors for the development of cardiovascular diseases, the present study was performed to evaluate the T cell immune responses specific to Pophylomonas gingivalis(P. gingivalis) heat shock protein(hsp) 60 and T-cell and B-cell epitope specificities for P. gingivalis hsp60 in atherosclerosis. Anti-P, gingivalis IgG antibody titers were elevated in all patients. We could establish P. gingivalis hsp-specific T cell lines from the atheroma lesions, a mixture of $CD4^+$ and $CD8^+$ cells producing the cytokines characteristic of both Th1 and Th2 subsets. of 108 overlapping synthetic peptides spanning whole P. gingivalis hsp60 molecule, ten peptides with common epitopes specificities for both T-cell and B-cell were identified. it was concluded that P. gingivalis hsp60 might K involved in the immunoregulatory process of atherosclerotic diseases with epitope specificities.

• Journal of Life Science
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• v.15 no.2 s.69
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• pp.253-260
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• 2005

Mitotic centromere-associated kinesin (MCAK), which is a member of the Kin I (internal motor domain) subfamily of kinesin-related proteins, is known to play a role in mitotic segregation of chromosome during M phase of the cell cycle. In the present study, we have produced a rat polyclonal antibody using human MCAK (HsMCAK) expressed in E. coli as the antigen. The antibody specifically recognized the HsMCAK protein (81 kDa), and could detect its nuclear localization in human Jurkat T cells and 293T cells by Western blot analysis. The specific stage of the cell cycle was obtained through blocking by either hydroxyl urea or nocodazole and subsequent releasing from each blocking for 2, 4, and 7 h. While the protein level of HsMCAK reached a maximum level in the S phase with slight decline in the $G_{2}-M$ phase, the electrophoretic mobility shift from $p81^{MCAK}\;to\;p84^{MCAK}$ began to be induced in the late S phase and reached a maximum level in the $G_{2}/M $ phase, and then it disappeared as the cells enter into the $G_{1}$ phase. Immunocytochemical analysis revealed that HsMCAK protein localized to centrosome and nucleus at the interphase, whereas it appeared to localize to the spindle pole, centromere of the condensed mitotic DNA, spindle fiber, or midbody, depending on the specific stage of the M phase. These results demonstrate that a rat polyclonal antibody raised against recombinant HsMCAK expressed in E. coli specifically detects human MCAK, and indicate that the electrophoretic mobility shift from $p81^{MCAK}\;to\;p84^{MCAK}$, which may be associated with its differential intracellular localization during the cell cycle, fluctuates with a maximum level of the shift at the $G_{2}-M$ phase.