Amplified Ca²⁺ dynamics and accelerated cell proliferation in breast cancer tissue during purinergic stimulation

Abstract

Intracellular Ca2+ dynamics shape malignant behaviors of cancer cells. Whereas previous studies focused on cultured cancer cells, we here used breast organoids and colonic crypts freshly isolated from human and murine surgical biopsies. We performed fluorescence microscopy to evaluate intracellular Ca2+ concentrations in breast and colon cancer tissue with preferential focus on intracellular Ca2+ release in response to purinergic and cholinergic stimuli. Inhibition of the sarco‐/endoplasmic reticulum Ca2+ ATPase with cyclopiazonic acid elicited larger Ca2+ responses in breast cancer tissue, but not in colon cancer tissue, relative to respective normal tissue. The resting intracellular Ca2+ concentration was elevated, and ATP, UTP and acetylcholine induced strongly augmented intracellular Ca2+ responses in breast cancer tissue compared with normal breast tissue. In contrast, resting intracellular Ca2+ levels and acetylcholine‐induced increases in intracellular Ca2+ concentrations were unaffected and ATP‐ and UTP‐induced Ca2+ responses were smaller in colon cancer tissue compared with normal colon tissue. In accordance with the amplified Ca2+ responses, ATP and UTP substantially increased proliferative activity—evaluated by bromodeoxyuridine incorporation—in breast cancer tissue, whereas the effect was minimal in normal breast tissue. ATP caused cell death—identified with ethidium homodimer‐1 staining—in breast cancer tissue only at concentrations above the expected pathophysiological range. We conclude that intracellular Ca2+ responses are amplified in breast cancer tissue, but not in colon cancer tissue, and that nucleotide signaling stimulates breast cancer cell proliferation within the extracellular concentration range typical for solid cancer tissue.

Bta-miR-6531 Regulates Calcium Influx in Bovine Leydig Cells and Is Associated with Sperm Motility

“…During spermatogenesis, ATP2A2 protein expression begins at the primary spermatocyte stage and maintains high signaling levels in the round and elongated spermatids [ 23 ]. Typically, ATP2A2 / SERCA2 regulate intracellular calcium into endoplasmic reticulum in cells [ 24 ]. The level of ATP2A2 / SERCA2 of sperm may related the calcium flex.…”

Antibodies toward Na+,HCO3–-cotransporter NBCn1/SLC4A7 block net acid extrusion and cause pH-dependent growth inhibition and apoptosis in breast cancer

“…MCF7 cells, NIH 3T3 cells with stable overexpression of human NBCn1, and primary organoids freshly isolated from human breast cancer tissue were loaded with 3 µM BCECF-AM (#B-1170, Invitrogen, Thermo Fisher Scientific) for 20–30 min at 37 °C. The preparations were mounted in a custom-built chamber [ 45 ]—continuously heated to 37 °C and aerated with 5% CO 2 /balance air or nominally CO 2 -free air—on the stage of an Olympus IX70 or Nikon Diaphot 200 microscope. BCECF-loaded cells and primary organoids were excited alternatingly at 490 nm and 440 nm and emission light collected at 510 nm with charge-coupled device-based fluorescence imaging systems controlled through EasyRatioPro (Photon Technology International, NJ, USA) or VisiView (Visitron Systems, Germany) software.…”

Carbonic anhydrases reduce the acidity of the tumor microenvironment, promote immune infiltration, decelerate tumor growth, and improve survival in ErbB2/HER2-enriched breast cancer

“…We obtained viable human tissue biopsies from 23 patients undergoing breast-conserving lumpectomy at the Department of Surgery, Randers Regional Hospital or the Department of Breast and Plastic Surgery, Aarhus University Hospital, Denmark [ 9 , 25 , 26 ]. Additional file 1 : Table S1 summarizes the clinical and pathological patient characteristics.…”

“…We acquired murine breast tissue from a mouse model with breast epithelial overexpression of ErbB2 [ 8 , 26 , 27 ]. These mice develop primary breast tumors at an average age of approximately 6 months [ 8 ].…”