Functional role of the Ca²⁺-activated Cl⁻ channel DOG1/TMEM16A in gastrointestinal stromal tumor cells.
DOG1, a Ca(2+)-activated Cl(-) channel (CaCC), was identified in 2004 to be robustly expressed in gastrointestinal stromal tumors (GIST). It was rapidly included as a tumor marker in routine diagnostics, but the functional role remained unknown. CaCCs are important regulators of normal physiological functions, but also implicated in tumorigenesis, cancer progression, metastasis, cell migration, apoptosis, proliferation and viability in several malignancies. We therefore investigated whether DOG1 plays a role in the three latter in GIST by utilizing in vitro cell model systems. Confocal microscopy identified different subcellular localizations of DOG1 in imatinib-sensitive and imatinib-resistant cells. Electrophysiological studies confirmed that DOG1-specific pharmacological agents possess potent activating and inhibiting properties. Proliferation assays showed small effects up to 72 h, and flow cytometric analysis of adherent cells with 7-AAD/Annexin V detected no pharmacological effects on viable GIST cells. However, inhibition of DOG1 conveyed pro-apoptotic effects among early apoptotic imatinib-resistant cells. In conclusion, DOG1 generates Cl(-) currents in GIST that can be regulated pharmacologically, with small effects on cell viability and proliferation in vitro. Inhibition of DOG1 might act pro-apoptotic on some early apoptotic GIST cell populations. Further studies are warranted to fully illuminate the function of DOG1 and its potential as therapeutic target.
Endocrine and Sarcoma Surgery Unit, Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden; Department of Breast and Endocrine Surgery, Karolinska University Hospital, Stockholm, Sweden. Electronic address: erik.berglund@ki.se.
Erik
E
Berglund
Department of Oncology-Pathology, Karolinska Institutet, Cancer Center Karolinska, Stockholm, Sweden.
Pinar
P
Akcakaya
Section for Transplantation Surgery, Department of Surgical Sciences, Uppsala University Hospital, Uppsala, Sweden.
David
D
Berglund
Endocrine and Sarcoma Surgery Unit, Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden; Department of Breast and Endocrine Surgery, Karolinska University Hospital, Stockholm, Sweden.
Fredrik
F
Karlsson
Department of Clinical Neuroscience, Karolinska Institutet, Stockholm, Sweden.
Vladana
V
Vukojević
Department of Oncology-Pathology, Karolinska Institutet, Cancer Center Karolinska, Stockholm, Sweden.
Linkiat
L
Lee
Endocrine and Sarcoma Surgery Unit, Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden.
Darko
D
Bogdanović
Department of Oncology-Pathology, Karolinska Institutet, Cancer Center Karolinska, Stockholm, Sweden.
Weng-Onn
WO
Lui
Department of Oncology-Pathology, Karolinska Institutet, Cancer Center Karolinska, Stockholm, Sweden.
Catharina
C
Larsson
Endocrine and Sarcoma Surgery Unit, Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden; Department of Breast and Endocrine Surgery, Karolinska University Hospital, Stockholm, Sweden.
Jan
J
Zedenius
Endocrine and Sarcoma Surgery Unit, Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden.
Robin
R
Fröbom
Endocrine and Sarcoma Surgery Unit, Department of Molecular Medicine and Surgery, Karolinska Institutet, Stockholm, Sweden; Department of Breast and Endocrine Surgery, Karolinska University Hospital, Stockholm, Sweden.
Robert
R
Bränström
D000075369:Anoctamin-1; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D065101:Chloride Channel Agonists; D018118:Chloride Channels / Q000037:antagonists & inhibitors / Q000378:metabolism*; D055724:Electrophysiological Phenomena; D005770:Gastrointestinal Neoplasms / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology; D046152:Gastrointestinal Stromal Tumors / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D009363:Neoplasm Proteins / Q000819:agonists / Q000037:antagonists & inhibitors / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D019009:Proto-Oncogene Proteins c-kit / Q000378:metabolism; D011743:Pyrimidines / Q000494:pharmacology; D013844:Thiazoles / Q000494:pharmacology
C476213:ANO1 protein, human; D000075369:Anoctamin-1; D065101:Chloride Channel Agonists; D018118:Chloride Channels; D009363:Neoplasm Proteins; D011743:Pyrimidines; C578466:T16AInh-A01; D013844:Thiazoles; D019009:Proto-Oncogene Proteins c-kit
DOG1; GIST; Gastrointestinal stromal tumor; Proliferation; TMEM16A; Viability