Dataset Information

Poly(adenosine diphosphate ribose) polymerase inhibitors induce autophagy-mediated drug resistance in ovarian cancer cells, xenografts, and patient-derived xenograft models.

ABSTRACT:

Background

Poly(adenosine diphosphate ribose) polymerase (PARP) inhibitors exhibit promising activity against ovarian cancers, but their efficacy can be limited by acquired drug resistance. This study explores the role of autophagy in regulating the sensitivity of ovarian cancer cells to PARP inhibitors.

Methods

Induction of autophagy was detected by punctate LC3 fluorescence staining, LC3I to LC3II conversion on Western blot analysis, and electron microscopy. Enhanced growth inhibition and apoptosis were observed when PARP inhibitors were used with hydroxychloroquine, chloroquine (CQ), or LYS05 to block the hydrolysis of proteins and lipids in autophagosomes or with small interfering RNA against ATG5 or ATG7 to prevent the formation of autophagosomes. The preclinical efficacy of the combination of CQ and olaparib was evaluated with a patient-derived xenograft (PDX) and the OVCAR8 human ovarian cancer cell line.

Results

Four PARP inhibitors (olaparib, niraparib, rucaparib, and talazoparib) induced autophagy in a panel of ovarian cancer cells. Inhibition of autophagy with CQ enhanced the sensitivity of ovarian cancer cells to PARP inhibitors. In vivo, olaparib and CQ produced additive growth inhibition in OVCAR8 xenografts and a PDX. Olaparib inhibited PARP activity, and this led to increased reactive oxygen species (ROS) and an accumulation of ?-H2AX. Inhibition of autophagy also increased ROS and ?-H2AX and enhanced the effect of olaparib on both entities. Treatment with olaparib increased phosphorylation of ATM and PTEN while decreasing the phosphorylation of AKT and mTOR and inducing autophagy.

Conclusions

PARP inhibitor-induced autophagy provides an adaptive mechanism of resistance to PARP inhibitors in cancer cells with wild-type BRCA, and a combination of PARP inhibitors with CQ or other autophagy inhibitors could improve outcomes for patients with ovarian cancer.

SUBMITTER: Santiago-O'Farrill JM

PROVIDER: S-EPMC6992526 | biostudies-literature | 2020 Feb

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Poly(adenosine diphosphate ribose) polymerase inhibitors induce autophagy-mediated drug resistance in ovarian cancer cells, xenografts, and patient-derived xenograft models.

Santiago-O'Farrill Janice M JM Weroha S John SJ Hou Xiaonan X Oberg Ann L AL Heinzen Ethan P EP Maurer Matthew J MJ Pang Lan L Rask Philip P Amaravadi Ravi K RK Becker Sarah E SE Romero Ignacio I Rubio Ma Jesús MJ Matias-Guiu Xavier X Santacana Maria M Llombart-Cussac Antonio A Poveda Andrés A Lu Zhen Z Bast Robert C RC

Cancer 20191112 4

<h4>Background</h4>Poly(adenosine diphosphate ribose) polymerase (PARP) inhibitors exhibit promising activity against ovarian cancers, but their efficacy can be limited by acquired drug resistance. This study explores the role of autophagy in regulating the sensitivity of ovarian cancer cells to PARP inhibitors.<h4>Methods</h4>Induction of autophagy was detected by punctate LC3 fluorescence staining, LC3I to LC3II conversion on Western blot analysis, and electron microscopy. Enhanced growth inhi ...[more]

PMID: 31714594

Similar Datasets

Project description:BackgroundMore patients with ovarian cancer are being treated with poly(adenosine diphosphate-ribose) polymerase inhibitors because regulatory agencies have granted these drugs new approvals for a variety of treatment indications. However, poly(adenosine diphosphate-ribose) polymerase inhibitors are expensive. When administered as a maintenance therapy, these drugs may be administered for months or years. How much of this cost patients experience as out-of-pocket spending is unknown.ObjectiveThis study aimed to estimate the out-of-pocket spending that patients experience during poly(adenosine diphosphate-ribose) polymerase inhibitor treatment and to characterize which healthcare services account for that spending.Study designA retrospective cohort study was performed with a sample of patients with ovarian cancer treated between 2014 and 2017 with olaparib, niraparib, or rucaparib. Patients were identified using MarketScan, a health insurance claims database. All insurance claims during poly(adenosine diphosphate-ribose) polymerase inhibitor treatment were collected. The primary outcome variable was the patients' out-of-pocket spending (copayment, coinsurance, and deductibles) during poly(adenosine diphosphate-ribose) polymerase inhibitor treatment for the medication itself. Other outcomes of interest included out-of-pocket spending for other healthcare services, the types and frequency of other healthcare services used, health plan spending, the estimated proportion of patients' household income used each month for healthcare, and patients' out-of-pocket spending immediately before poly(adenosine diphosphate-ribose) polymerase inhibitor treatment.ResultsWe identified 503 patients with ovarian cancer with a median age of 55 years (interquartile range, 50-62 years); 83% of those had out-of-pocket spendings during poly(adenosine diphosphate-ribose) polymerase inhibitor treatment. The median treatment duration was 124 days (interquartile range, 66-240 days). The mean out-of-pocket spending for poly(adenosine diphosphate-ribose) polymerase inhibitors was $305 (standard deviation, $2275) per month. On average, this accounted for 44.8% (standard deviation, 34.8%) of the patients' overall monthly out-of-pocket spending. The mean out-of-pocket spending for other healthcare services was $165 (standard deviation, $769) per month. Health plans spent, on average, $12,661 (standard deviation, $15,668) per month for poly(adenosine diphosphate-ribose) polymerase inhibitors and $7108 (standard deviation, $15,254) per month for all other healthcare services. The cost sharing for office visits, laboratory tests, and imaging studies represented the majority of non-poly(adenosine diphosphate-ribose) polymerase inhibitor treatment out-of-pocket spending. The average amount patients paid for all healthcare services per month during poly(adenosine diphosphate-ribose) polymerase inhibitor treatment was $470 (standard deviation, $2407), which was estimated to be 8.7% of the patients' monthly household income. The mean out-of-pocket spending in the 12 months before poly(adenosine diphosphate-ribose) polymerase inhibitor treatment was $3110 (standard deviation, $6987).ConclusionPatients can face high out-of-pocket costs for poly(adenosine diphosphate-ribose) polymerase inhibitors, although the sum of cost sharing for other healthcare services used during poly(adenosine diphosphate-ribose) polymerase inhibitor treatment is often higher. The spending on healthcare costs consumes a large proportion of these patients' household income. Patients with ovarian cancer experience high out-of-pocket costs for healthcare, both before and during poly(adenosine diphosphate-ribose) polymerase inhibitor treatment.

Project description:The poly-(adenosine diphosphate-ribose) polymerase (PARP) family of proteins participates in numerous functions, most notably the DNA damage response. Cancer vulnerability to DNA damage has led to development of several PARP inhibitors (PARPi). This class of drugs has demonstrated therapeutic efficacy in ovarian, breast, and prostate cancers, but with variable response. Consequently, clinics need to select patients likely to benefit from these targeted therapies. In vivo imaging of 18F-fluorthanatrace uptake has been shown to correspond to PARP-1 expression in tissue. This study characterized the pharmacokinetics of 18F-fluorthanatrace and tested kinetic and static models to guide metric selection in future studies assessing 18F-fluorthanatrace as a biomarker of response to PARPi therapy. Methods: Fourteen prospectively enrolled ovarian cancer patients were injected with 18F-fluorthanatrace and imaged dynamically for 60 min after injection followed by up to 2 whole-body scans, with venous blood activity and metabolite measurements. SUVmax and SUVpeak were extracted from dynamic images and whole-body scans. Kinetic parameter estimates and SUVs were assessed for correlations with tissue PARP-1 immunofluorescence (n = 7). Simulations of population kinetic parameters enabled estimation of measurement bias and precision in parameter estimates. Results: 18F-fluorthanatrace blood clearance was variable, but labeled metabolite profiles were similar across patients, supporting use of a population parent fraction curve. The total distribution volume from a reversible 2-tissue-compartment model and Logan reference tissue distribution volume ratio (DVR) from the first hour of PET acquisition correlated with tumor PARP-1 expression by immunofluorescence (r = 0.76 and 0.83, respectively; P < 0.05). DVR bias and precision estimates were 6.4% and 29.1%, respectively. SUVmax and SUVpeak acquired from images with midpoints of 57.5, 110 ± 3, and 199 ± 4 min highly correlated with PARP-1 expression (mean ± SD, r ≥ 0.79; P < 0.05). Conclusion: Tumor SUVmax and SUVpeak at 55-60 min after injection and later and DVR from at least 60 min appear to be robust noninvasive measures of PARP-1 binding. 18F-fluorthanatrace uptake in ovarian cancer was best described by models of reversible binding. However, pharmacokinetic patterns of tracer uptake were somewhat variable, especially at later time points.

Dataset Information

Poly(adenosine diphosphate ribose) polymerase inhibitors induce autophagy-mediated drug resistance in ovarian cancer cells, xenografts, and patient-derived xenograft models.

Background

Methods

Results

Conclusions

Publications

Poly(adenosine diphosphate ribose) polymerase inhibitors induce autophagy-mediated drug resistance in ovarian cancer cells, xenografts, and patient-derived xenograft models.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets