PKCδ Inhibition Impairs Mammary Cancer Proliferative Capacity But Selects Cancer Stem Cells, Involving Autophagy.
Protein kinase C (PKC) is a family of serine/threonine kinases that regulate diverse cellular functions including cell death, proliferation, and survival. Recent studies have reported that PKCδ, are involved in apoptosis or autophagy induction. In the present study we focused on how PKCδ regulates proliferation and cancer stem cell (CSC) properties of the hormone-independent mammary cancer cell line LM38-LP, using pharmacological and genetic approaches. We found that pharmacological inhibition of PKCδ, by Rottlerin treatment, impairs in vitro LM38-LP proliferation through cell cycle arrest, inducing the formation of cytoplasmic-vacuoles. Using immunofluorescence we confirmed that Rottlerin treatment induced the apparition of LC3 dots in cell cytoplasm, and increased autophagy flux. On the other side, the same treatment increased CSC growth rate and self-renewal. Furthermore, Rottlerin pre-treatment induced in CSC the development of a "grape-like" morphology when they are growing in 3D cultures (Matrigel), usually associated with a malignant phenotype, as well as an increase in the number of experimental lung metastasis when these cells were inoculated in vivo. The PKCδ knockdown, by RNA interference, induced autophagy and increased CSC number, indicating that these effects are indeed exerted through a PKCδ dependent pathway. Finally, the increase in the number of mammospheres could be reversed by a 3MA treatment, suggesting that autophagy mechanism is necessary for the increased of CSC self-renewal induced by PKCδ inhibition. Here we demonstrated that PKCδ activity exerts a dual role through the autophagy mechanism, decreasing proliferative capacity of mammary tumor cells but also regulating tumor stem cell self-renewal.
Research Area, Institute of Oncology "Angel H. Roffo", University of Buenos Aires, Buenos Aires, Argentina.
Damián E
DE
Berardi
Research Area, Institute of Oncology "Angel H. Roffo", University of Buenos Aires, Buenos Aires, Argentina.
Carolina
C
Flumian
Research Area, Institute of Oncology "Angel H. Roffo", University of Buenos Aires, Buenos Aires, Argentina.
Cristina E
CE
Rodriguez
Research Area, Institute of Oncology "Angel H. Roffo", University of Buenos Aires, Buenos Aires, Argentina.
María I Díaz
MI
Bessone
Research Area, Institute of Oncology "Angel H. Roffo", University of Buenos Aires, Buenos Aires, Argentina.
Stefano M
SM
Cirigliano
Research Area, Institute of Oncology "Angel H. Roffo", University of Buenos Aires, Buenos Aires, Argentina.
Elisa D Bal de Kier
ED
Joffé
Research Area, Institute of Oncology "Angel H. Roffo", University of Buenos Aires, Buenos Aires, Argentina.
Gabriel L
GL
Fiszman
Research Area, Institute of Oncology "Angel H. Roffo", University of Buenos Aires, Buenos Aires, Argentina.
Alejandro J
AJ
Urtreger
Research Area, Institute of Oncology "Angel H. Roffo", University of Buenos Aires, Buenos Aires, Argentina.
Laura B
LB
Todaro
D000098:Acetophenones / Q000494:pharmacology; D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology; D001343:Autophagy; D001578:Benzopyrans / Q000494:pharmacology; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D000066673:Cell Self Renewal; D004354:Drug Screening Assays, Antitumor; D005260:Female; D008175:Lung Neoplasms / Q000201:enzymology* / Q000556:secondary; D008325:Mammary Neoplasms, Experimental / Q000201:enzymology* / Q000473:pathology; D051379:Mice; D008807:Mice, Inbred BALB C; D000071317:Nanog Homeobox Protein / Q000235:genetics / Q000378:metabolism; D009368:Neoplasm Transplantation; D014411:Neoplastic Stem Cells / Q000502:physiology*; D051745:Protein Kinase C-delta / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D047428:Protein Kinase Inhibitors / Q000494:pharmacology
D000098:Acetophenones; D000970:Antineoplastic Agents; D001578:Benzopyrans; D000071317:Nanog Homeobox Protein; C475540:Nanog protein, mouse; D047428:Protein Kinase Inhibitors; C085746:rottlerin; C497259:Prkcd protein, mouse; D051745:Protein Kinase C-delta
AUTOPHAGY; CANCER STEM CELLS; MAMMARY CANCER; PROTEIN KINASE Cδ