scholarly journals MYC as a driver of stochastic chromatin networks: implications for the fitness of cancer cells

2020 ◽  
Vol 48 (19) ◽  
pp. 10867-10876
Author(s):  
Noriyuki Sumida ◽  
Emmanouil G Sifakis ◽  
Narsis A Kiani ◽  
Anna Lewandowska Ronnegren ◽  
Barbara A Scholz ◽  
...  

Abstract The relationship between stochastic transcriptional bursts and dynamic 3D chromatin states is not well understood. Using an innovated, ultra-sensitive technique, we address here enigmatic features underlying the communications between MYC and its enhancers in relation to the transcriptional process. MYC thus interacts with its flanking enhancers in a mutually exclusive manner documenting that enhancer hubs impinging on MYC detected in large cell populations likely do not exist in single cells. Dynamic encounters with pathologically activated enhancers responsive to a range of environmental cues, involved <10% of active MYC alleles at any given time in colon cancer cells. Being the most central node of the chromatin network, MYC itself likely drives its communications with flanking enhancers, rather than vice versa. We submit that these features underlie an acquired ability of MYC to become dynamically activated in response to a diverse range of environmental cues encountered by the cell during the neoplastic process.

2009 ◽  
Vol 99 (6) ◽  
pp. 361-367 ◽  
Author(s):  
Yoichi Matsuo ◽  
Hirozumi Sawai ◽  
Jiachi Ma ◽  
Donghui Xu ◽  
Nobuo Ochi ◽  
...  

2016 ◽  
Vol 2 (1) ◽  
Author(s):  
Birgitta Holmlund ◽  
Annica Holmqvist

Particularly interesting new cysteine-histidine rich protein (PINCH) is related to poor outcome in colorectal cancers. Here, the relationship between PINCH-1 and cell survival in colon cancer cells was analyzed and the signaling pathways regulated by PINCH-1 by using PINCH-1 siRNA. KM12C cells were treated with PINCH-1 siRNA or control siRNA. Cell number was analyzed by crystal violet staining and caspase-3 activity was assessed using a fluorescent substrate. PINCH-1 extra- and intracellular pathways in KM12C cells were investigated, using phospho-kinase/phospho-receptor tyrosine kinase (RTK) antibody arrays. The expression of c-Myc was evaluated by Quantitative real-time PCR (qPCR) and Western blot analysis. Cell number was significantly decreased (P=0.003) and the caspase-3 activity increased (P=0.019) in PINCH-1 depleted KM12C cultures compared to siRNA cultures. In PINCH-1 silenced KM12C cells, the levels of EGFR and ERK1/2 were significantly decreased (P=0.008, P=0.003, respectively) compared to their controls, as were the c-Myc mRNA and protein expressions (P=0.0073, P=0.0002, respectively). Down-regulation of PINCH-1 reduced the cell survival and lowers the levels of EGFR, ERK1/2 and c-Myc in colon cancer cells. PINCH-1 is essential for cell survival, and may be a future target for anticancer therapy. 


2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Bi-Qing Cai ◽  
Wan-Meng Chen ◽  
Jia Zhao ◽  
Wei Hou ◽  
Jian-Cai Tang

Increasing evidence indicates that nuclear factor, erythroid 2-like 3 (Nrf3) is connected with tumorigenesis. However, the relationship between Nrf3 and tumor drug resistance remains elusive. In this study, we investigated the effect and mechanism of action by which Nrf3 regulated the sensitivity of colon cancer cells to 5-fluorouracil (5-FU). We found Nrf3 was significantly increased in colon cancer tissues. Furthermore, we observed that Nrf3 knockdown and overexpression can significantly affect the sensitivity of colon cancer cells to 5-FU in vitro and in vivo. Moreover, Nrf3 promoted the expression of RELA, P-RELA, and BCL-2. Inhibition of NF-κB partly reversed the effects of Nrf3 overexpression, resulting in the resistance of colon cancer cells to 5-FU. Overall, the study revealed that Nrf3 was connected to the sensitivity of colon cancer cells to 5-FU, and its possible mechanism was related to the NF-κB signaling pathway, which provided a new target for overcoming the resistance of colon cancer cells to 5-FU.


2020 ◽  
Vol 21 (5) ◽  
pp. 1826
Author(s):  
Joanna Depciuch ◽  
Bartosz Klębowski ◽  
Małgorzata Stec ◽  
Rafał Szatanek ◽  
Kazimierz Węglarczyk ◽  
...  

Colon cancer constitutes 33% of all cancer cases in humans and the majority of patients with metastatic colon cancer still have poor prognosis. An important role in cancer development is the communication between cancer and normal cells. This may occur, among others, through extracellular vesicles (including microvesicles) (MVs), which are being released by both types of cells. MVs may regulate a diverse range of biological processes and are considered as useful cancer biomarkers. Herein, we show that similarity in the general chemical composition between colon cancer cells and their corresponding tumor-derived microvesicles (TMVs) does exist. These results have been confirmed by spectroscopic methods for four colon cancer cell lines: HCT116, LoVo, SW480, and SW620 differing in their aggressiveness/metastatic potential. Our results show that Raman and Fourier Transform InfraRed (FTIR) analysis of the cell lines and their corresponding TMVs did not differ significantly in the characterization of their chemical composition. However, hierarchical cluster analysis of the data obtained by both of the methods revealed that only Raman spectroscopy provides results that are in line with the molecular classification of colon cancer, thus having potential clinical relevance.


Molecules ◽  
2020 ◽  
Vol 25 (7) ◽  
pp. 1654 ◽  
Author(s):  
Olga Wesołowska ◽  
Krystyna Michalak ◽  
Maria Błaszczyk ◽  
Joseph Molnár ◽  
Kamila Środa-Pomianek

Multidrug resistance (MDR) that occurs in cancer cells constitutes one of the major reasons for chemotherapy failure. The main molecular mechanism of MDR is overexpression of protein transporters from the ATP-binding cassette (ABC) superfamily, such as ABCB1 (multidrug resistance protein 1 (MDR1), P-glycoprotein). At the expense of ATP hydrolysis, ABCB1 pumps a diverse range of substrates (including anticancer drugs) out of the cell, thereby reducing their intracellular concentration. In the present study, the ability of two patented disiloxanes (SILA-409 and SILA-421) to reverse drug resistance in human colon adenocarcinoma cell lines LoVo and LoVo/Dx was investigated. It was demonstrated that both compounds in concentrations of 0.5–1 µM strongly increased the sensitivity of LoVo/Dx cells to doxorubicin. By means of an accumulation test in which rhodamine 123 was used as an ABCB1 substrate analogue, both organosilicon compounds were also shown to inhibit ABCB1 transport activity. The intracellular accumulation of doxorubicin was also increased, and more drug entered the cellular nuclei of resistant cells in the presence of the studied compounds. In conclusion, both SILA-409 and SILA-421 were demonstrated to be effective MDR reversal agents in resistant human colon cancer cells.


2001 ◽  
Vol 120 (5) ◽  
pp. A493-A493
Author(s):  
J HARDWICK ◽  
G VANDENBRINK ◽  
S VANDEVENTER ◽  
M PEPPELENBOSCH

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