GZ17-6.02 and palbociclib interact to kill ER+ breast cancer cells

Abstract

GZ17-6.02 is presently undergoing clinical evaluation in solid tumors and lymphoma. The present studies were performed to define its biology in estrogen receptor positive breast cancer cells and to determine whether it interacted with palbociclib to enhance tumor cell killing. GZ17-6.02 interacted in an additive fashion with palbociclib to kill ER+ breast cancer cells. GZ17-6.02 and palbociclib cooperated to inactivate mTOR and AKT and to activate ULK1 and PERK. The drugs interacted to increase the expression of FAS-L and BAX, and to decrease the levels of MCL1, the estrogen receptor, and HDACs 1-3. Palbociclib activated ERBB3, an effect blocked by GZ17-6.02. GZ17-6.02 and palbociclib interacted to increase the expression of multiple toxic BH3 domain proteins and to reduce MCL1 and BCL-XL expression. Knock down of FAS-L reduced the lethality of [GZ17-6.02 + palbociclib]. GZ17-6.02 and palbociclib interacted to enhance autophagosome formation and autophagic flux. Knock down of Beclin1, ATG5, BAG3, eIF2α, toxic BH3 domain proteins or CD95 significantly reduced drug combination lethality. GZ17-6.02 and palbociclib increased the expression of Beclin1 and ATG5, effects blocked by knock down of eIF2α. The drugs also increased the phosphorylation of the AMPK and ATG13, effects blocked by knock down of ATM. Knock down of ATM or the AMPK, or expression of activated mTOR significantly reduced the abilities of GZ17-6.02 and palbociclib to enhance autophagosome formation and autophagic flux.

GZ17-6.02 and axitinib interact to kill renal carcinoma cells

“…The UOK121LN cell isolate was kindly supplied by Dr. Marston Linehan (Nation Cancer Institute, Bethesda, MD) Axitinib was purchased from Selleckchem (Houston, TX). All Materials were obtained as described in the references [ 1 – 6 ]. Trypsin-EDTA, DMEM, RPMI, penicillin-streptomycin were purchased from GIBCOBRL (GIBCOBRL Life Technologies, Grand Island, NY).…”

“…Trypsin-EDTA, DMEM, RPMI, penicillin-streptomycin were purchased from GIBCOBRL (GIBCOBRL Life Technologies, Grand Island, NY). Other reagents and performance of experimental procedures were as described [ 1 – 6 ]. Antibodies were purchased from Cell Signaling Technology (Danvers, MA); Abgent (San Diego, CA); Novus Biologicals (Centennial, CO); Abcam (Cambridge, UK); and Santa Cruz Biotechnology (Dallas, TX).…”

“…Specific multiple independent siRNAs to knock down the expression of CD95, FADD, Beclin1, ATG5 AMPKα 1 , ATM, BIM, BAX, BAK, BID and eIF2α, and scramble control, were purchased from Qiagen (Hilden, Germany) and Thermo Fisher (Waltham, MA). Control studies were presented showing on-target specificity of our siRNAs, primary antibodies, and our phospho-specific antibodies to detect both total protein levels and phosphorylated levels of proteins [ 1 – 6 ] ( Figure 10 ).…”

“…GZ17-6.02 has three components: curcumin, harmine and isovanillin and is presently undergoing phase I safety evaluation in cancer patients with solid tumors and lymphoma (NCT03775525) [ 1 – 6 ]. Over the past two years we have published data demonstrating that GZ17-6.02 kills a wide range of tumor cell types, including ER+ breast, colorectal, pancreatic, hepatic, biliary, NSCLC, cutaneous melanoma, sarcoma and actinic keratoses [ 1 – 6 ].…”

“…Our prior molecular findings with GZ17-6.02 demonstrated that it caused DNA damage and activated an ATM-AMPK-ULK1-ATG13 pathway, concomitant with inactivation of mTORC1 and mTORC2, resulting in enhanced autophagosome formation followed by autophagic flux. Knock down of autophagy regulatory proteins such as Beclin1 or ATG5, or knock down of ATM, AMPKα or ULK1 suppressed autophagosome formation and tumor cell killing by GZ17-6.02 [ 1 – 6 ]. GZ17-6.02 activated PKR-like endoplasmic reticulum kinase (PERK) and increased the phosphorylation (inactivation) of eIF2α.…”