A Sequential Targeting Strategy Interrupts AKT-Driven Subclone-Mediated Progression in Glioblastoma

Abstract

Purpose: Therapy resistance and fatal disease progression in glioblastoma are thought to result from the dynamics of intra-tumor heterogeneity. This study aimed at identifying and molecularly target tumor cells that can survive, adapt, and subclonally expand under primary therapy. Experimental Design: To identify candidate markers and to experimentally access dynamics of subclonal progression in glioblastoma, we established a discovery cohort of paired vital cell samples obtained before and after primary therapy. We further used two independent validation cohorts of paired clinical tissues to test our findings. Follow-up preclinical treatment strategies were evaluated in patient-derived xenografts. Results: We describe, in clinical samples, an archetype of rare ALDH1A1+ tumor cells that enrich and acquire AKT-mediated drug resistance in response to standard-of-care temozolomide. Importantly, we observe that drug resistance of ALDH1A1+ cells is not intrinsic, but rather an adaptive mechanism emerging exclusively after temozolomide treatment. In patient cells and xenograft models of disease, we recapitulate the enrichment of ALDH1A1+ cells under the influence of temozolomide. We demonstrate that their subclonal progression is AKT-driven and can be interfered with by well-timed sequential rather than simultaneous antitumor combination strategy. Conclusion: Drug-resistant ALDH1A1+/pAKT+ subclones accumulate in patient tissues upon adaptation to temozolomide therapy. These subclones may therefore represent a dynamic target in glioblastoma. Our study proposes the combination of temozolomide and AKT inhibitors in a sequential treatment schedule as a rationale for future clinical investigation.

KDM5B predicts temozolomide-resistant subclones in glioblastoma

“…As an entry route to the investigation of TMZ-resistant cell states, we screened the described KDM family genes for their potential involvement in the TMZ-driven expansion of ALDH1A1+ cellular hierarchies ( Figure 1 A). We used an established cohort 5 of short-term in vitro expanded, vital patient cells representing pairs of treatment-naive and respective TMZ-experienced relapse samples derived from n = 8 IDH -wt glioblastoma individuals ( Table S1 ). Quantitative assessment via qPCR did not reveal a correlation of ALDH1A1 expression levels between the pairs of treatment-naive vs. relapse samples ( Figures 1 B and S1 A).…”

“… 1 , 2 , 3 , 4 We have recently described a rare ALDH1A1+, stem-like cell population in treatment-naive glioblastoma that acquires pAKT and subclonally expands under the influence of TMZ in models of disease and during clinical progression. 5 We were curious to follow up on the observation, aiming to decipher the early mechanisms that promote this cellular behavior. It is considered that adaptive plasticity of glioblastoma cells may be the result of a cooperation and interplay of genetic events and epigenetic adaptions that jointly lead to drug resistance.…”

Gene signatures associated with prognosis and chemotherapy resistance in glioblastoma treated with temozolomide

“…To determine whether the genes correlated with OS could also discriminate between TMZ-resistant and control GBM cell lines or tumors, gene expression data in the GSE151680, GSE193957, and GSE145128 datasets were analyzed. GSE151680 had RNA-seq data for three TMZ-resistant and three control samples for each of two GBM cell lines (U87 and U251); GSE193957 had microarray data for three TMZ-resistant and three control samples from the U87 cell line ( Choo et al, 2023 ); GSE145128 had microarray data for treatment-naïve tumor and the matched tumor that recurred after TMZ treatment in seven GBM patients ( Kebir et al, 2023 ).…”

Investigation of sponge medium for efficient concurrent tumor treating fields and radiotherapy for glioblastomas

“…[6][7][8] With persistent efforts made in the past few years, several viable strategies, including tumor resection, radiotherapy, chemotherapy with temozolomide (TMZ), and immunotherapy, have been developed. [9][10][11] Despite some success, therapy efficacy is still challenging, and the associated adverse effects seriously impact the quality of patients' life. 12,13 Fortunately, TTFields provide a noninvasive method to cure GBMs through affixing transducer arrays on the scalp, which deliver a local low-intensity alternating current electric field (100-400 kHz) locoregionally around the anatomic region of the tumor and selectively disrupt cell division.…”

“…6–8 With persistent efforts made in the past few years, several viable strategies, including tumor resection, radiotherapy, chemotherapy with temozolomide (TMZ), and immunotherapy, have been developed. 9–11 Despite some success, therapy efficacy is still challenging, and the associated adverse effects seriously impact the quality of patients' life. 12,13…”