Proto-Oncogene Proteins c-jun

Publication Title: 
The Journal of Biological Chemistry

Two genes (MAT1A and MAT2A) encode for methionine adenosyltransferase (MAT), an essential cellular enzyme responsible for S-adenosylmethionine biosynthesis. MAT1A is expressed mostly in the liver, whereas MAT2A is widely distributed. We showed a switch from MAT1A to MAT2A expression in human hepatocellular carcinoma (HCC), which facilitates cancer cell growth. Using DNase I footprinting analysis, we previously identified a region in the MAT2A promoter protected from DNase I digestion in HCC.

Author(s): 
Yang, Heping
Sadda, Mamatha R.
Yu, Victor
Zeng, Ying
Lee, Taunia D.
Ou, Xiaopeng
Chen, Lixin
Lu, Shelly C.
Publication Title: 
Carcinogenesis

It is well documented that arachidonic acid (AA) and its metabolites are intimately linked to cancer biology. However, the downstream mechanism(s) that link AA levels to cancer cell proliferation remain to be elucidated. Initial experiments in the current study showed that exogenous AA and inhibitors of AA metabolism that lead to the accumulation of unesterified AA are cytotoxic to the colon cancer cell line, HCT-116. Additionally, exogenous AA and triacsin C, an inhibitor of AA acylation, induced apoptosis and related caspase-3 activity in a transcriptionally dependent manner.

Author(s): 
Monjazeb, Arta M.
High, Kevin P.
Connoy, Abbie
Hart, Lori S.
Koumenis, Constantinos
Chilton, Floyd H.
Publication Title: 
Biochemical and Biophysical Research Communications

c-JUN is a major component of heterodimer transcription factor AP-1 (Activator Protein-1) that activates gene transcription in cell proliferation, inflammation and stress responses. SIRT1 (Sirtuin 1) is a histone deacetylase that controls gene transcription through modification of chromatin structure. However, it is not clear if SIRT1 regulates c-JUN activity in the control of gene transcription. Here, we show that SIRT1 associated with c-JUN in co-immunoprecipitation of whole cell lysate, and inhibited the transcriptional activity of c-JUN in the mammalian two hybridization system.

Author(s): 
Gao, Zhanguo
Ye, Jianping
Publication Title: 
Experimental Dermatology

Solar ultraviolet (UV) radiation, particularly its UVB (290-320 nm) component, is the primary cause of many adverse biological effects including photoageing and skin cancer. UVB radiation causes DNA damage, protein oxidation and induces matrix metalloproteinases (MMPs). Photochemoprevention via the use of botanical antioxidants in affording protection to human skin against UVB damage is receiving increasing attention. Pomegranate, from the tree Punica granatum, contains anthocyanins and hydrolysable tannins and possesses strong antioxidant and anti-tumor-promoting properties.

Author(s): 
Afaq, Farrukh
Zaid, Mohammad Abu
Khan, Naghma
Dreher, Mark
Mukhtar, Hasan
Publication Title: 
The Journal of Biological Chemistry

Macrophages are essential components of innate immunity, and apoptosis of these cells impairs mucosal defense to microbes. Helicobacter pylori is a gastric pathogen that infects half of the world population and causes peptic ulcer disease and gastric cancer. The host inflammatory response fails to eradicate the organism. We have reported that H. pylori induces apoptosis of macrophages by generation of polyamines from ornithine decarboxylase (ODC), which is dependent on c-Myc as a transcriptional enhancer.

Author(s): 
Asim, Mohammad
Chaturvedi, Rupesh
Hoge, Svea
Lewis, Nuruddeen D.
Singh, Kshipra
Barry, Daniel P.
Algood, Holly S.
de Sablet, Thibaut
Gobert, Alain P.
Wilson, Keith T.
Publication Title: 
Oncogene

Estrogen receptor-α (ERα, ESR1) is a pivotal transcriptional regulator of breast cancer physiology and is targeted by endocrine therapies. Loss of ERα activity or expression is an indication of endocrine resistance and is associated with increased risk of tumor recurrence and worse prognosis. In this study, we sought to investigate whether elements of the tumor microenvironment, namely macrophages, would impact on ERα and we found that macrophage-derived factors caused loss of ERα expression in breast cancer cells.

Author(s): 
Stossi, F.
Madak-Erdoğan, Z.
Katzenellenbogen, B. S.
Publication Title: 
Experimental Cell Research

Methionine adenosyltransferase (MAT) is an essential enzyme that is responsible for the biosynthesis of S-adenosylmethionine (SAMe), the principal methyl donor and precursor of polyamines. MAT1A is expressed in normal liver and MAT2A is expressed in all extrahepatic tissues. MAT2A expression is increased in human colon cancer and in colon cancer cells treated with mitogens, whereas silencing MAT2A resulted in apoptosis. The aim of the current work was to examine the mechanism responsible for MAT2A-dependent growth and apoptosis.

Author(s): 
Tomasi, Maria Lauda
Ryoo, Minjung
Skay, Anna
Tomasi, Ivan
Giordano, Pasquale
Mato, José M.
Lu, Shelly C.
Publication Title: 
PloS One

Acupuncture (AP) has been used worldwide to relieve pain. However, the mechanism of action of AP is poorly understood. Here, we found that AP relieved neuropathic pain (NP) by inhibiting Jun-N-terminal kinase (JNK) activation in astrocytes after spinal cord injury (SCI). After contusion injury which induces the below-level (L4-L5) NP, Shuigou (GV26) and Yanglingquan (GB34) acupoints were applied. At 31 d after injury, both mechanical allodynia and thermal hyperalgesia were significantly alleviated by AP applied at GV26 and GB34.

Author(s): 
Lee, Jee Y.
Choi, Doo C.
Oh, Tae H.
Yune, Tae Y.
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