Integrative analysis of therapy resistance and transcriptomic profiling data in glioblastoma cells identifies sensitization vulnerabilities for combined modality radiochemotherapy

Abstract

Background Inherent resistance to radio/chemotherapy is one of the major reasons for early recurrence, treatment failure, and dismal prognosis of glioblastoma. Thus, the identification of resistance driving regulators as prognostic and/or predictive markers as well as potential vulnerabilities for combined modality treatment approaches is of pivotal importance. Methods We performed an integrative analysis of treatment resistance and DNA damage response regulator expression in a panel of human glioblastoma cell lines. mRNA expression levels of 38 DNA damage response regulators were analyzed by qRT-PCR. Inherent resistance to radiotherapy (single-shot and fractionated mode) and/or temozolomide treatment was assessed by clonogenic survival assays. Resistance scores were extracted by dimensionality reduction and subjected to correlation analyses with the mRNA expression data. Top-hit candidates with positive correlation coefficients were validated by pharmacological inhibition in clonogenic survival assays and DNA repair analyses via residual γH2AX/53BP1-foci staining. Results Inherent resistance to single-shot and similarly also to fractionated radiotherapy showed strong positive correlations with mRNA expression levels of known vulnerabilities of GBM, including PARP1, NBN, and BLM, as well as ATR and LIG4—two so far underestimated targets. Inhibition of ATR by AZD-6738 resulted in robust and dose-dependent radiosensitization of glioblastoma cells, whereas LIG4 inhibition by L189 had no noticeable impact. Resistance against temozolomide showed strong positive correlation with mRNA expression levels of MGMT as to be expected. Interestingly, it also correlated with mRNA expression levels of ATM, suggesting a potential role of ATM in the context of temozolomide resistance in glioblastoma cells. ATM inhibition exhibited slight sensitization effects towards temozolomide treatment in MGMT low expressing glioblastoma cells, thus encouraging further characterization. Conclusions Here, we describe a systematic approach integrating clonogenic survival data with mRNA expression data of DNA damage response regulators in human glioblastoma cell lines to identify markers of inherent therapy resistance and potential vulnerabilities for targeted sensitization. Our results provide proof-of-concept for the feasibility of this approach, including its limitations. We consider this strategy to be adaptable to other cancer entities as well as other molecular data qualities, and its upscaling potential in terms of model systems and observational data levels deserves further investigation.

Chemical Activation and Mechanical Sensitization of Piezo1 Enhance TRAIL-Mediated Apoptosis in Glioblastoma Cells

“…Previous studies have shown that LN18 cells are more resistant to TMZ than U87 cells . TMZ is a chemotherapy commonly prescribed with radiotherapy as the first line of defense against GBM since it is one of a few cancer drugs that can penetrate the blood–brain barrier .…”

“…Previous studies have shown that LN18 cells are more resistant to TMZ than U87 cells. 36 TMZ is a chemotherapy commonly prescribed with radiotherapy as the first line of defense against GBM since it is one of a few cancer drugs that can penetrate the blood–brain barrier. 37 TMZ has toxic side effects and is not a transcription-independent method of targeting cancer cells, so GBM cells can become resistant to the therapy, resulting in tumor reoccurrence.…”

Polyoxometalate Nanoparticles as a Potential Glioblastoma Therapeutic via Lipid-Mediated Cell Death

“…These data suggest that the mechanism of cell death is not primarily due to lipid peroxidation. This finding is of particular importance because U251 cells are considerably more resistant to ionizing radiation than other glioblastoma cell lines, and POM-based nanoparticle platforms may provide a novel therapeutic outlet to overcome resistance [ 26 ]. Thus, both Mo- and W-POMs may have therapeutic potential in glioblastoma cells by serving as a reserve of redox-active metals to induce cell death.…”

Proton pump inhibitors display anti‐tumour potential in glioma

“…Chemoradiotherapy resistance is an important element to early recurrence, treatment failure and dismal prognosis of glioblastoma 277 . With growing amounts of evidence that chemoradiotherapy may induce the more normal cells to glioma leading to recurrence and progression 278,279 .…”

“…Chemoradiotherapy resistance is an important element to early recurrence, treatment failure and dismal prognosis of glioblastoma. 277 With growing amounts of evidence that chemoradiotherapy may induce the more normal cells to glioma leading to recurrence and progression. 278 , 279 Even if the concentration of drugs entering plasma and cerebrospinal fluid is enough to inhibit the progression of the tumour, the drug resistance and progression of glioma also happen from time to time.…”