Autosomal dominant hypocalcemia (ADH) type 1 and 2 are disorders of calcium homeostasis caused by gain of function variants. The calcium-sensing receptor (CaSR) is a class C GPCR that responds to elevated extracellular calcium (Ca²⁺ _o) by inhibiting parathyroid hormone (PTH) secretion and promoting renal excretion of Ca²⁺ and other salts to restore physiologically normal Ca²⁺ _o concentrations. CaSR negative allosteric modulators (NAMs) transiently raise PTH levels in individuals with ADH1, restoring Ca²⁺ _o concentration to a physiological normal range. Herein we disclose the discovery of a chemoreactive NAM (ATF936-NCS, 4) for the CaSR that (i) is wash-resistant indicative of irreversible receptor binding and (ii) stimulates prolonged PTH release in vivo. This 'first-in-class' chemical probe will provide invaluable insight towards the development of longer acting NAMs for the treatment of ADH.

OBJECTIVETo investigate the effects of 50% ethyl alcohol (EtOH) extracts from Danzhi Xiaoyao Pill (, DXP) on the proliferation of MCF-7 human breast cancer cells and potential mechanisms.

METHODSATP-Lite assay was performed to test the proliferation of the MCF-7 breast cancer cell line; and antioxidant activity was measured by the oxygen radical absorbance capacity (ORAC). The effects of DXP on nitric oxide (NO) production were tested by lipopolysaccharide (LPS)-stimulated RAW 264.7 murine macrophages using the Griess reaction.

RESULTSThe 50% EtOH DXP extracts displayed a cytotoxic response on MCF-7 cells at 0.10, 0.25 and 0.50 mg/mL dose-dependently with the proliferation inhibited by more than 85%. The ORAC value of the DXP was 820 micro moL Trolox equivalent/g, about 40% of the vitamin C value. DXP extracts had significant inhibitory effect on NO production at the concentration from 0.0625 mg/mL to 0.5 mg/mL (P<0.05, P<0.01).

CONCLUSIONThe extracts of DXP could significantly inhibit the proliferation of MCF-7 cells, with the effect possibly related to its antioxidant activity and the inhibition of NO production.

Antioxidants ; pharmacology ; Breast Neoplasms ; pathology ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Drugs, Chinese Herbal ; pharmacology ; Female ; Humans ; Lipopolysaccharides ; pharmacology ; Nitric Oxide ; biosynthesis