Arginine starvation and docetaxel induce c-Myc–driven HENT1 surface expression to overcome gemcitabine resistance in ASS1-negative tumors
BC Prudner, R Rathore, AM Robinson, A Godec… - Clinical Cancer …, 2019 - AACR
Clinical Cancer Research, 2019•AACR
Purpose: The response to acute and long-term arginine starvation results in a conditional
adaptive metabolic reprogramming that can be harnessed for therapeutic opportunities in
ASS1-negative tumors. Here, we investigate the underlying biology of priming ASS1−
tumors with arginine deiminase (ADI-PEG20) before treatment with gemcitabine (GEM) and
docetaxel (DTX) in sarcoma, pancreatic cancer, and melanoma cell lines. Experimental
Design: ASS1− tumor cell lines were treated to create LTAT (long-term ADI treated) cell lines …
adaptive metabolic reprogramming that can be harnessed for therapeutic opportunities in
ASS1-negative tumors. Here, we investigate the underlying biology of priming ASS1−
tumors with arginine deiminase (ADI-PEG20) before treatment with gemcitabine (GEM) and
docetaxel (DTX) in sarcoma, pancreatic cancer, and melanoma cell lines. Experimental
Design: ASS1− tumor cell lines were treated to create LTAT (long-term ADI treated) cell lines …
Purpose
The response to acute and long-term arginine starvation results in a conditional adaptive metabolic reprogramming that can be harnessed for therapeutic opportunities in ASS1-negative tumors. Here, we investigate the underlying biology of priming ASS1− tumors with arginine deiminase (ADI-PEG20) before treatment with gemcitabine (GEM) and docetaxel (DTX) in sarcoma, pancreatic cancer, and melanoma cell lines.
Experimental Design
ASS1− tumor cell lines were treated to create LTAT (long-term ADI treated) cell lines (ASS1+) and used for drug combination studies. Protein expression of ASS1, dCK, RRM2, E2F1, c-MYC, and hENT1 was measured. c-MYC activity was determined, live-cell immunofluorescent studies for hENT1, uptake assays of FITC-cytosine probe, and rescue studies with a c-MYC inhibitor were all determined in the presence or absence of the ADI-PEG20:GEM:DTX.
Results
In examining modulations within the pyrimidine pathway, we identified that the addition of DTX to cells treated with ADI-PEG20 resulted in translocation of stabilized c-Myc to the nucleus. This resulted in an increase of hENT1 cell-surface expression and rendered the cells susceptible to GEM. In vivo studies demonstrate that the combination of ADI-PEG20:GEM:DTX was optimal for tumor growth inhibition, providing the preclinical mechanism and justification for the ongoing clinical trial of ADI-PEG20, GEM, and DTX in sarcoma.
Conclusions
The priming of tumors with ADI-PEG20 and DTX results in the stabilization of c-MYC potentiating the effect of GEM treatment via an increase in hENT1 expression. This finding is applicable to ASS1-deficient cancers that are currently treated with GEM.
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