Journal of Cancer Research and Clinical Oncology
ORIGINAL ARTICLE – CANCER RESEARCH
Eﬀects of sequentially applied single and combined temozolomide,
hydroxychloroquine and AT101 treatment in a long-term stimulation
glioblastoma in vitro model
· Christina Schmitt
· Florian Ceynowa
· Rainer Adelung
· Ralph Lucius
· Michael Synowitz
· Janka Held‑Feindt
Received: 11 April 2018 / Accepted: 27 May 2018
© Springer-Verlag GmbH Germany, part of Springer Nature 2018
Purpose Glioblastoma multiforme (GBM) is a poorly curable disease due to its heterogeneity that enables single cells to
survive treatment regimen and initiate tumor regrowth. Although some progress in therapy has been achieved in the last years,
the eﬃcient treatment of GBMs is still a clinical challenge. Besides the standard therapeutic drug temozolomide (TMZ),
quinoline-based antimalarial drugs such as hydroxychloroquine (HCQ) and BH3 mimetics such as AT101 were considered
as possible drugs for GBM therapy.
Methods We investigated the eﬀects of sequentially applied single and combined TMZ, HCQ and AT101 treatments in a
long-term stimulation GBM in vitro model. We performed all investigations in parallel in human astrocytes and two diﬀeren-
tially TMZ-responsive human GBM cell lines and adjusted used drug concentrations to known liquor/plasma concentrations
in patients. We determined amounts of dead cells and still remaining growth rates and depicted our results in a heatmap-like
summary to visualize which sequential long-term treatment schedule seemed to be most promising.
Results We showed that sequential stimulations yielded higher cytotoxicity and better tumor growth control in comparison
to single TMZ treatment. This was especially the case for the sequences TMZ/HCQ and TMZ + AT101/AT101 which was as
eﬀective as the non-sequential combination TMZ + AT101. Importantly, those aﬀected both less and more TMZ-responsive
glioma cell lines, whilst being less harmful for astrocytes in comparison to single TMZ treatment.
Conclusions Sequential treatment with mechanistically diﬀerent acting drugs might be an option to reduce side eﬀects in
long-term treatment, for example in local administration approaches.
Keywords R-(−)-gossypol · Alternative drugs · Sequential treatment · Quinoline-based drugs · BH3 mimetics ·
CHOP CCAAT-enhancer-binding protein homolo-
CI Combination index
DMEM Dulbecco’s modiﬁed Eagle’s medium
DMSO Dimethyl sulfoxide
ER Endoplasmatic reticulum
FBS Fetal bovine serum
Vivian Adamski and Christina Schmitt share ﬁrst authorship.
Kirsten Hattermann and Janka Held-Feindt share senior
Electronic supplementary material The online version of this
article (https ://doi.org/10.1007/s0043 2-018-2680-y) contains
supplementary material, which is available to authorized users.
* Janka Held-Feindt
Department of Neurosurgery, University Medical
Center Schleswig-Holstein UKSH, Campus Kiel,
Arnold-Heller-Str.3, Building 41, 24105 Kiel, Germany
Department of Anatomy, University of Kiel, 24118 Kiel,
Institute for Materials Science, University of Kiel,
24143 Kiel, Germany