scholarly journals Cell cycle arrest explained the observed bulk 3D genomic alterations in response to long term heat shock for mammalian cells

2021 ◽  
Author(s):  
Bingxiang Xu ◽  
Xiaomeng Gao ◽  
Xiaoli Li ◽  
Yan Jia ◽  
Feifei Li ◽  
...  

AbstractHeat shock is a common environmental stress, while the response of the nucleus to it remains controversial in mammalian cells. Acute reaction and chronic adaptation to environmental stress may have distinct internal rewiring in the gene regulation networks. However, this difference remains largely unexplored. Here, we report that chromatin conformation and chromatin accessibility respond differently in short- and long-term heat shock in human K562 cells. Interestingly, we found that chromatin conformation in K562 cells was largely stable in response to short heat shock, while showed clear and characteristic changes after long-term heat treatment with little alteration in chromatin accessibility during the whole process. We further showed in silico and experimental evidence strongly suggesting that changes in chromatin conformation may largely stem from an accumulation of cells in the M stage of cell cycle in response to heat shock. Our results represent a paradigm shift away from the controversial view of chromatin response to heat shock and emphasize the necessity of cell cycle analysis while when interpreting bulk Hi-C data.

Oncotarget ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 300-301
Author(s):  
Hao Yang ◽  
Hui Hui ◽  
Qian Wang ◽  
Hui Li ◽  
Kai Zhao ◽  
...  

Author(s):  
Wipob Suttana ◽  
Chatubhong Singharachai ◽  
Rawiwan Charoensup ◽  
Narawadee Rujanapun ◽  
Chutima Suya

Chemotherapy can cause multidrug resistance in cancer cells and is cytotoxic to normal cells. Discovering natural bioactive compounds that are not cytotoxic to normal cells but inhibit proliferation and induce apoptosis in drug- sensitive and drug-resistant cancer cells could overcome these drawbacks of chemotherapy. This study investigated the antiproliferative effects of crude extracts of Benchalokawichian (BLW) remedy and its herbal components against drug-sensitive and drug-resistant cancer cells, cytotoxicity of the extracts toward normal cells, and their ability to induce apoptosis and cell cycle arrest in drug-sensitive and drug-resistant cancer cells. The extracts exhibited antiproliferative activity against doxorubicin-sensitive and doxorubicin-resistant erythromyelogenous leukemic cells (K562 and K562/adr). Tiliacora triandra root, BLW, and Harrisonia perforata root extracts displayed an IC50 of 77.00 ± 1.30, 79.33 ± 1.33, and 87.67 ± 0.67 µg/mL, respectively, against K562 cells. In contrast, Clerodendrum petasites, T. triandra, and H. perforata root extracts displayed the lowest IC50 against K562/adr cells (68.89 ± 0.75, 78.33 ± 0.69, and 86.78 ± 1.92 µg/mL, respectively). The resistance factor of the extracts was lower than that of doxorubicin, indicating that the extracts could overcome the multidrug resistance of cancer cells. Importantly, the extracts were negligibly cytotoxic to peripheral mononuclear cells, indicating minimal adverse effects in normal cells. In addition, these extracts induced apoptosis of K562 and K562/adr cells and caused cell cycle arrest at the G0/G1 phase in K562 cells. Keywords: Antiproliferative, Apoptosis, Benchalokawichian, Cell cycle, Multidrug resistance


2020 ◽  
Vol 21 (14) ◽  
pp. 5077
Author(s):  
Bin Zhang ◽  
Ting Zhang ◽  
Tian-Yi Zhang ◽  
Ning Wang ◽  
Shan He ◽  
...  

Chronic myeloid leukemia (CML) is a malignant tumor caused by the abnormal proliferation of hematopoietic stem cells. Among a new series of acridone derivatives previously synthesized, it was found that the methoxybenzyl 5-nitroacridone derivative 8q has nanomolar cytotoxicity in vitro against human chronic myelogenous leukemia K562 cells. In order to further explore the possible anti-leukemia mechanism of action of 8q on K562 cells, a metabolomics and molecular biology study was introduced. It was thus found that most of the metabolic pathways of the G1 phase of K562 cells were affected after 8q treatment. In addition, a concentration-dependent accumulation of cells in the G1 phase was observed by cell cycle analysis. Western blot analysis showed that 8q significantly down-regulated the phosphorylation level of retinoblastoma-associated protein (Rb) in a concentration-dependent manner, upon 48 h treatment. In addition, 8q induced K562 cells apoptosis, through both mitochondria-mediated and exogenous apoptotic pathways. Taken together, these results indicate that 8q effectively triggers G1 cell cycle arrest and induces cell apoptosis in K562 cells, by inhibiting the CDK4/6-mediated phosphorylation of Rb. Furthermore, the possible binding interactions between 8q and CDK4/6 protein were clarified by homology modeling and molecular docking. In order to verify the inhibitory activity of 8q against other chronic myeloid leukemia cells, KCL-22 cells and K562 adriamycin-resistant cells (K562/ADR) were selected for the MTT assay. It is worth noting that 8q showed significant anti-proliferative activity against these cell lines after 48 h/72 h treatment. Therefore, this study provides new mechanistic information and guidance for the development of new acridones for application in the treatment of CML.


1994 ◽  
Vol 300 (1) ◽  
pp. 201-209 ◽  
Author(s):  
G Elia ◽  
M G Santoro

Synthesis of heat-shock proteins (HSPs) is universally induced in eukaryotic and prokaryotic cells by exposure to elevated temperatures or to other types of environmental stress. In mammalian cells, HSPs belonging to the 70 kDa family (HSP70) have a regulatory role in several cellular processes, and have been shown to be involved in the control of cell proliferation and differentiation. Although many types of HSP70 inducers have been identified, only a few compounds, all belonging to the flavonoid group, have been shown to inhibit HSP70 induction. Because inhibitors of HSP70 synthesis could be an important tool with which to study the function of this protein, we have investigated the effect of quercetin, a flavonoid with antiproliferative activity which is widely distributed in nature, on HSP70 synthesis in human K562 erythroleukaemia cells after treatment with severe or mild heat shock and with other inducers. Quercetin was found to affect HSP70 synthesis at more than one level, depending on the conditions used. Indeed, after severe heat shock (45 degrees C for 20 min) treatment with quercetin, at non-toxic concentrations, was found to inhibit HSP70 synthesis for a period of 3-4 h. This block appeared to be exerted at the post-transcriptional level and to be cell-mediated, as the addition of quercetin during translation of HSP70 mRNA in vitro had no effect. After prolonged (90 min) exposure at 43 degrees C, however, quercetin was found to inhibit also HSP70 mRNA transcription. Pretreatment of K562 cells with quercetin had no effect on HSP70 expression, and quercetin needed to be present during induction to be effective. Under all conditions tested, the quercetin-induced block of HSP70 synthesis was found to be transient and, after an initial delay, synthesis of HSP70 reached the control rate and continued at the same level for several hours after the time at which HSP70 synthesis had been turned off in control cells. Finally, inhibition of HSP70 synthesis by quercetin appeared to be dependent on the temperature used and on the type of stressor.


Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 4290-4290
Author(s):  
Ina Fabian ◽  
Debby Haite ◽  
Avital Levitov ◽  
Drora Halperin ◽  
Itamar Shalit

Abstract We previously reported that the fluoroquinolone moxifloxacin (MXF) inhibits NF-kB, mitogen-activated protein kinase activation and the synthesis of proinflammatory cytokines in activated human monocytic cells (AAC48:1974,2004). Since MXF acts on topoisomerase II (Topo II) in mammalian cells, we investigated its effect in combination with another Topo II inhibitor, VP-16, on cell proliferation (by the MTT method), cell cycle, caspase-3 activity and proinflammatory cytokine release in THP-1 and Jurkat cells. THP-1 cells were incubated for 24 h with 0.5–3 μg/ml VP-16 in the presence or absence of 5–20 μg/ml MXF. VP-16 induced a dose dependent decrease in cell proliferation. An additional 2.5-and 1.6-fold decrease in cell proliferation was observed upon incubation of the cells with 0.5 or 1 μg/ml VP-16 and 20 μg/ml MXF, respectively (up to 69% inhibition). To further elucidate the mechanism of the antiproliferative activity of MXF, its effect on cell cycle progression was investigated. In control cultures 1%, 45%,18% and 36% of cells were in G0, G1, S and G2/M phases at 24 h, respectively. In contrast, in cultures treated with 1 μg/ml VP-16 and VP-16+ 20 μg/ml MXF, the number of cells in G1 decreased to 5.4 and 6.5%, respectively, while the number of cells in S phase increased to 25.5 and 42%, respectively and the number of cells in G2/M cells increased to 60 and 44%, respectively. These data provide evidence for S-G2/M cell cycle arrest induced by VP-16 and that addition of MXF shifted the S-G2/M arrest more towards the S phase. Since the antiproliferative effects of MXF could also be attributed to apoptotic cell death in addition to cell cycle arrest, we investigated the effect of the drugs on apoptosis. Using the fluorogenic assay for caspse-3 activity, we show that incubation of THP-1 cells for 6 h with 1.5 μg/ml VP-16 resulted in 630±120 unit/50μg protein of caspase-3 activity while the combination of 1.5 μg/ml VP-16 and 20 μg/ml MXF enhanced caspase-3 activity up to 1700±340 units/50μg protein (vs.233±107 in control cells), indicating that MXF synergises with VP-16 in activation of caspase-3. In Jurkat cells, the addition of 0.5 or 1 μg/ml VP-16, did not affect cell proliferation while in the presence of 20 μg/ml MXF and 1 μg/ml VP-16 there was a 62% decrease in cell proliferation (p<0.05). Exposure of Jurkat cells to 3 μg/ml VP-16 alone resulted in 504±114 units/50μg protein of caspase-3 activity and the addition of 20μg/ml MXF enhanced caspase-3 activity up to 1676± 259 units/50μg protein (vs 226±113 units/50μg protein in control cells). We further examined pro-inflammatory cytokine secretion upon stimulation of THP-1 cells with VP-16, MXF or their combination. VP-16 alone at 3 μg/ml increased IL-8 and TNF-α secretion from THP-1 cells by 2.5 and 1.8-fold respectively. Addition of MXF (5–20 μg/ml) inhibited the two cytokines secretion by 72–77% and 58–72%, respectively. The above combined data indicate that MXF, at clinically attainable concentrations, demonstrates pronounced synergistic effect with VP-16 as an anti-proliferative agent mainly by enhancing caspase-3 activity and apoptosis. At the same time MXF inhibits the pro-inflammatory effects conferred by VP-16 in the tumor cells studied. The clinical significance of the above anti-proliferative and anti-inflammatory effects of MXF in combination with VP-16 should be further investigated in animal models.


Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 3991-3991
Author(s):  
Jie Jin ◽  
Jia-Kun Shen ◽  
Hua-ping Du ◽  
Min Yang ◽  
Yun-Gui Wang

Abstract Casticin, a component from Vitex rotundifolia wich was widely used as an anti-inflammatory agent in Chinese traditional medicine, was reported to have anti-tumor activities in lung cancer and breast cancer. There are yet no reports on roles against acute myelocytic leukemia (AML). This study aims to elucidate the anti-leukemic activity of casticin on AML cells. We investigated the efficient efficacy and the mechanisms by which casticin triggers cell death in AML cells by analyzing cell cycle perturbations, apoptosis-related marker expression. Cell viability was measured by MTT method; apoptosis and cell cycle arrest were determined by flow cytometry and AV-PI assay. Western blot was performed to measure the apoptosis-related marker. Concentration-dependant cell deaths were observed in AML cell lines including K562, U937 and THP-1, with IC50 values of 24h (hours) being 47.4μM, 67.8μM and 61.7μM, respectively. Time-dependant cell deaths were also observed. At the concentration of 20μM casticin, 45.7%, 76.1% and 80.9% of K562 cells were inhibited at 24h, 48h and 72h, respectively; 24.7%, 30% and 61% of U937 cells were inhibited at 24h, 48h and 72h, respectively; while for THP-1, 29%, 41.8% and 53.9% were inhibited at 24h, 48h and 72h, respectively. Apoptosis was found using AV-PI staining by flow cytometry analysis. We observed an obvious G2/M phase increase prolongation in casticin treated K562 cells. BThe distribitions of G2/M phase were 2.9%, 33.6%, 75.3%, 54.9%, 29.7% and 27.0% in K562 cells after treated by 20μM casticin for 0h, 6h, 12h, 24h, 36h and 48h, respectively. Furthermore, apoptosis-related proteins, PARP and caspase 3, were cleaved in casticin treated K562 cells. Taken together, these results demonstrated that casticin can induce leukemic cell death through apoptosis, suggesting that casticin could be a promising therapeutic agent against acute myeloid leukemia.


Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 1333-1333
Author(s):  
Seiichi Okabe ◽  
Tetsuzo Tauchi ◽  
Seiichiro Katagiri ◽  
Yuko Tanaka ◽  
Kazuma Ohyashiki

Abstract Abstract 1333 Chronic myeloid leukemia (CML) is characterized by cytogenetic aberration (Philadelphia chromosome: Ph) and chimeric tyrosine kinase BCR-ABL. ABL tyrosine kinase inhibitor, imatinib has demonstrated the potency against CML patients. However, resistance to imatinib can develop in CML patients due to BCR-ABL point mutations. One of T315I mutation is resistant to currently available ABL tyrosine kinase inhibitors. Therefore, new approach against T315I mutant may improve the outcome of Ph-positive leukemia patients. Aurora kinases are serine/threonine kinases and upregulated in many malignancies including leukemia, and play an important role in cell cycle control and tumor proliferations. Because Aurora kinases are overexpressed in leukemia cells, Aurora kinases may present attractive targets for leukemia treatment. One of Aurora kinase inhibitor, MLN8237 (alisertib) is an oral and selective Aurora kinase A inhibitor and is currently being investigated in a pivotal phase 3 clinical trial against hematological malignancies. We suggested that alisertib mediated inhibition Aurora kinase activity and in combination with ponatinib, also known as AP24534 may abrogate the proliferation and survival of Ph-positive cells including T315I mutation. In this study, we investigated the combination therapy with a ponatinib and an alisertib by using the BCR-ABL positive cell line, K562, murine Ba/F3 cell line which was transfected with T315I mutant, ponatinib resistant Ba/F3 cells and T315I primary sample. Protein expression of Aurora A and B were increased in Ph-positive leukemia cells. 72 hours treatment of alisertib exhibits cell growth inhibition and induced apoptosis against K562 cells in a dose dependent manner. Alisertib also induced cell cycle arrest. The treatment of ponatinib exhibits cell growth inhibition partially against K562 cells in the presence of feeder cell (HS-5) conditioned media. We found that the treatment of alisertib abrogated the protective effects of HS-5 conditioned media in K562 cells. We investigated the alisertib activity against T315I positive cells. Alisertib potently induced cell growth inhibition of Ba/F3 cells ectopically expressing T315I mutation and induced cell cycle arrest. We investigated the efficacy between ponatinib and alisertib by using these cell lines. Combined treatment of Ba/F3 T315I cells with ponatinib and alisertib caused significantly more cytotoxicity than each drug alone. Ponatinib and alisertib were also effective against T315I primary samples. We examined the intracellular signaling of alisertib. Phosphorylation of Aurora A was inhibited in a time dependent manner. We also found the phosphorylation of histone H3 was also reduced in a dose dependent manner suggested that high concentration of alisertib also inhibits Aurora B activity. We next investigated by using ponatinib resistant Ba/F3 cells. In the ponatinib resistant cell lines, IC50 of ponatinib was up to 200 nM. BCR-ABL triple point mutations (T315I, E255K and Y253H) were detected by direct sequence analysis. The treatment of alisertib exhibits cell growth inhibition against Ba/F3 ponatinib resistant cells in the dose dependent manner. Alisertib induced cell cycle arrest in ponatinib resistant cells. Combined treatment of Ba/F3 ponatinib resistant cells with ponatinib and alisertib caused significantly more cytotoxicity. To assess the activity of alisertib and ponatinib, we performed to test on CML tumor formation in mice. We injected nude mice subcutaneously with 1×107 Ba/F3 T315I cells. A dose of 30 mg/kg/day p.o of ponatinib and 30 mg/kg/day p.o of alisertib inhibited tumor growth and reduced tumor volume compared with control mice. The treatments were well tolerated with no animal health concerns observed indicating the feasibility of alisertib combination strategies in the clinic. Data from this study suggested that administration of the ponatinib and Aurora inhibitor, alisertib may be a powerful strategy against BCR-ABL mutant cells including T315I. Disclosures: No relevant conflicts of interest to declare.


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