It has been widely reported that CHO cells undergo apoptosis in culture, despite supplementation of nutrients through fed-batch strategies. Improvement of cell viability in culture can effectively improve recombinant protein yield through extension of the culture's production lifespan, especially at high cell densities. Heat shock proteins (HSPs) have been reported to demonstrate anti-apoptotic effects against a wide range of physical and chemical stimuli through their ability to bind and act as antagonists to critical apoptotic molecules.
Artesunate is a semisynthetic derivative from artemisinin, a natural product from the Chinese herb Artemisia annua L. It exerts antimalarial activity, and, additionally, artemisinin and its derivatives are active against cancer cells. The active moiety is an endoperoxide bridge. Its cleavage leads to the formation of reactive oxygen species and carbon-centered radicals. These highly reactive molecules target several proteins in Plasmodia, which is thought to result in killing of the microorganism. DNA damage induced by artemisinins has not yet been described.
Biochemical and Biophysical Research Communications
Limonene is a major aromatic compound in essential oils extracted from citrus rind. The application of limonene, especially in aromatherapy, has expanded significantly, but its potential effects on cellular metabolism have been elusive. We found that limonene directly binds to the adenosine A(2A) receptor, which may induce sedative effects. Results from an in vitro radioligand binding assay showed that limonene exhibits selective affinity to A(2A) receptors.
The Chinese Hamster ovary (CHO) cell line is widely used for measuring drug cytotoxicity and resistance. Therefore, the effects of two major Ayurvedic drugs (W. somnifera root and E. officinalis fruits) on the short and long-term growth of these cells were investigated. A standard 96-well plate assay was used to measure short-term growth. For assessment of long-term growth, the colony formation assay (CFA) was used, which measures clonogenic potential. This assay is the best measure of the cytotoxicity of anticancer drugs and the radio-sensitivity of tumor cells.
Black cohosh is a commonly used botanical dietary supplement for the treatment of climacteric complaints. Because the opiate system in the brain is intimately associated with mood, temperature, and sex hormonal levels, the activity of black cohosh extracts at the human mu opiate receptor (hMOR) expressed in Chinese hamster ovary cells was investigated. The 100% methanol, 75% ethanol, and 40% 2-propanol extracts of black cohosh effectively displaced the specific binding of [3H]DAMGO to hMOR.
The Journal of Pharmacology and Experimental Therapeutics
Ephedra species of plants have both beneficial and adverse effects primarily associated with the presence of ephedrine alkaloids. Few reports have appeared that examine the direct actions of ephedrine alkaloids on human subtypes of adrenergic receptors (ARs). In the present study, ephedrine alkaloids were evaluated for their binding affinities on human alpha(1A)-, alpha(1B)-, alpha(1D)-, alpha(2A)-, alpha(2B)-, and alpha(2C)-AR subtypes expressed in HEK and Chinese hamster ovary cells.
Biochemical and Biophysical Research Communications
The epithelial Na(+) channel (ENaC) is an essential channel responsible for Na(+) reabsorption. Coexpression of Rab11a and Rab3a small G proteins with ENaC results in a significant increase in channel activity. In contrast, coexpression of Rab5, Rab27a, and Arf-1 had no effect or slightly decreased ENaC activity. Inhibition of MEK with PD98059, Rho-kinase with Y27632 or PI3-kinase with LY294002 had no effect on ENaC activity in Rab11a-transfected CHO cells. Fluorescence imaging methods demonstrate that Rab11a colocalized with ENaC.
The Journal of Steroid Biochemistry and Molecular Biology
Estrogen exposure and metabolism may play an important role in the development of estrogen-sensitive cancers in postmenopausal women. In this study we investigated whether past oral contraceptive (OC) administration or current dietary isoflavonoids (IF) affected expression and/or activity of steroid hormone-metabolizing cytochrome P450 (CYP) enzymes using complementary primate and cell culture models.
Cimicifuga racemosa (L.) Nutt. (syn. Actaea racemosa L., black cohosh) is used to relieve menopausal hot flashes, although clinical studies have provided conflicting data, and the active constituent(s) and mechanism(s) of action remain unknown. Because serotonergic receptors and transporters are involved with thermoregulation, black cohosh and its phytoconstituents were evaluated for serotonergic activity using 5-HT7 receptor binding, cAMP induction, and serotonin selective re-uptake inhibitor (SSRI) assays.
INTRODUCTION: Earlier studies reported serotonergic activity for cimicifugic acids (CA) isolated from Cimicifuga racemosa. The discovery of strongly basic alkaloids, cimipronidines, from the active extract partition and evaluation of previously employed work-up procedures has led to the hypothesis of strong acid/base association in the extract. OBJECTIVE: Re-isolation of the CAs was desired to permit further detailed studies. Based on the acid/base association hypothesis, a new separation scheme of the active partition was required, which separates acids from associated bases.