Autophagy Inhibition Using Hydrochloroquine in Breast Cancer Patients:a Pilot Study
In response to various stresses, cells can launch a process of "self-eating", termed
autophagy. Thereby, components of the cell are catabolically digested via specific lysosomes
called autophagosomes, to provide the cell with energy and other necessary factors to serve
as a temporary survival mechanism (Chen et al. 2010).
Two major stressors that can be evaded by autophagy are important for cancer progression and
1. cells can respond with autophagy to cytotoxic treatment such as chemo- or endocrine
therapy, thereby leading to treatment insensitivity (Kondo et al. 2005; Chen et al.
2. cells can survive severe hypoxia using autophagy (Rouschop et al. 2010), and hypoxic
cells themselves are refractory to chemo-, endocrine and radiotherapy.
Thus, tumor cells evade treatment induced cell death by launching a temporary last survival
mechanism. Inhibition of this pathway could lead to sensitization for a variety of cancer
treatment regimen, or to specific cell killing of tumor associated hypoxic cells that would
otherwise be refractory to radiotherapy. Chloroquine (CQ),
N'-(7-chloroquinoline-4-yl)-N,N-diethyl-pentane-1,4-diamine, was discovered in 1934, and has
widely been used as an effective and safe anti-malarial and anti-rheumatoid agent since
1947. Later, CQ has been rediscovered as a sensitizer of cytotoxic cancer therapies such as
ionizing radiation and chemotherapeutics, although the precise mechanism behind this has
remained largely unknown (Solomon and Lee 2009). Most recently, it was discovered that CQ
inhibits the process of autophagy by impairment of autophagic vesicle clearance, as CQ
accumulates in lysosomal vesicles. This has now lead to several investigators proposing that
CQ or one of its analogs can be used to inhibit the autophagic pathway as an additive to
other cytotoxic treatments. Hydrochloroquine (HCQ, Plaquenil) is a CQ derivative with fewer
side effects than CQ, which has long been used as anti-malarial and antirheumatoid agent. It
can be safely used at high doses for extended periods of time. Both CQ and HCQ are under
investigation in clinical trials for glioblastoma, small and non-small cell lung cancer,
breast cancer, prostate cancer, melanoma, renal cell carcinoma, and pancreatic cancer (for
reviews see Solomon and Lee 2009 and Chen et al. 2010).
However, the effect of HCQ on tumor tissue, autophagy and/or oxygenation has of yet not been
studied in human patients in vivo.
In this pilot study we intend to investigate the effect of HCQ on breast cancer tissues. To
this end, breast cancer patients that have given informed consent for participation in the
AFTER study (AMO 2010/312), but are not included as their tissue biopsy is found to be
ER/PgR negative, will be asked to take 800 mg once, and then 400 mg/day HCQ for 2 to 3 weeks
until surgery. We will compare tissue characteristics before and after treatment using HCQ,
looking at effects on markers for both hypoxia and autophagy using immunohistochemistry. We
expect that after treatment with HCQ tumor cells in hypoxic areas will no longer be able to
survive, thus decreasing the number of viable hypoxic cells and increasing the amount of
necrosis. This pilot study will serve as a proof of principle for future studies into the
effect of autophagy inhibition on treatment sensitivity in breast cancer
Endpoint Classification: Efficacy Study, Intervention Model: Single Group Assignment, Masking: Open Label, Primary Purpose: Treatment
differences in endogenous hypoxia markers (CA9, PAI-1, VEGF [Rademakers et al. 2008]) and autophagy (LC3b [Rouschop et al. 2010]) before and after treatment with HCQ. These parameters will be quantified by immunohistochemistry on formalin fixed paraffin embedded tissue from both pretreatment biopsy, and posttreatment surgically obtained material.
before and after short-term pre-surgical treatment with HCQ
P. Span, Md
University Medical Centre Nijmegen
Netherlands: The Central Committee on Research Involving Human Subjects (CCMO)