Blockage of SLC31A1‐dependent copper absorption increases pancreatic cancer cell autophagy to resist cell death

Abstract

Objectives: Clinical observations have demonstrated that copper levels elevate in several cancer types, and copper deprivation is shown to inhibit tumour angiogenesis and growth in both animal models and preclinical trials. However, the content of copper in pancreatic duct adenocarcinoma (PDAC) and whether it is a potential therapy target is still unknown. Materials and Methods:The levels of copper in PDAC specimens were detected by ICP-MS assays. Copper depletion in Panc-1 or MiaPaCa-2 cells was conducted via copper transporter 1 (SLC31A1) interference and copper chelator tetrathiomolybdate (TM) treatment. The effects of copper deprivation on cancer cells were evaluated by cell proliferation, migration, invasion, colony formation and cell apoptosis.The mechanism of copper deprivation-caused cancer cell quiescence was resolved through mitochondrial dysfunction tests and autophagy studies. The tumour-suppression experiments under the condition of copper block and/or autophagy inhibition were performed both in vitro and in xenografted mice.Results: SLC31A1-dependent copper levels are correlated with the malignant degree of pancreatic cancer. Blocking copper absorption could inhibit pancreatic cancer progression but did not increase cell death. We found that copper deprivation increased mitochondrial ROS level and decreased ATP level, which rendered cancer cells in a dormant state. Strikingly, copper deprivation caused an increase in autophagy to resist death of pancreatic cancer cells. Simultaneous treatment with TM and autophagy inhibitor CQ increased cell death of cancer cells in vitro and retarded cancer growth in vivo. Conclusions:These findings reveal that copper deprivation-caused cell dormancy and the increase in autophagy is a reason for the poor clinical outcome obtained from copper depletion therapies for cancers. Therefore, the combination of autophagy inhibition and copper depletion is potentially a novel strategy for the treatment of pancreatic cancer and other copper-dependent malignant tumours.

The Comparison of Selected Types of Municipal Sewage Sludge Filtrates Toxicity in Different Biological Models: From Bacterial Strains to Mammalian Cells. Preliminary Study

“…It should be also mentioned that copper level could be elevated in several types of cancer, which may mean that selected metals are essential for cancer cells growth and development. This results from the fact that, according to Yu et al, copper deprivation inhibits tumor angiogenesis and growth [40]. We observed a connection between an elevated copper level in SS1 and the stimulation of cancer cell viability.…”

miR‐128‐3p contributes to mitochondrial dysfunction and induces apoptosis in glioma cells via targeting pyruvate dehydrogenase kinase 1

“…Cell viability was examined using the cell counting Kit‐8 (CCK‐8) (Beyotime, Shanghai, China) assay according to that previously described . U87 and U373 cells were placed in a 96‐well plate at a density of 5,000–800 cells/well.…”

“…Cell viability was examined using the cell counting Kit-8 (CCK-8) (Beyotime, Shanghai, China) assay according to that previously described. 33 U87 and U373 cells were placed in a 96-well plate at a density of 5,000-800 cells/well. Cells were adhered for 24 hr at 37 C and then transfected with si-PDK1, si-PDK2, si-PDK3, si-PDK4, or miR-128-3p mimic, respectively.…”

“…Intracellular ROS levels were measured using 2,7-dichlorodihydrofluorescein diacetate (DCFH-DA; S0033, Beyotime) according to that previously described. 33 Cultured U87 cells were washed once and incubated with 10 μM DCFH-DA, 30 min in the dark. Relative DCFH fluorescence of cells was analyzed using the BD flow cytometer (BD C6 Biosciences).…”

Current Biomedical Use of Copper Chelation Therapy

“…Accordingly, copper chelation using TM has been shown to inhibit the Unc-51-like autophagy activating kinase 1 and 2 (Ulk1/2) in lung adenocarcinoma cells [155]. Recently, the combination of copper chelation with TM and autophagy inhibition by chloroquine has been evaluated to promote pancreatic cancer cells death [156].…”