Modeling Therapy-Driven Evolution of Glioblastoma with Patient-Derived Xenografts

Adult-type diffusely infiltrating gliomas, of which glioblastoma is the most common and aggressive, almost always recur after treatment and are fatal. Improved understanding of therapy-driven tumor evolution and acquired therapy resistance in gliomas is essential for improving patient outcomes, yet the majority of the models currently used in preclinical research are of therapy-naïve tumors. Here, we describe the development of therapy-resistant IDH-wildtype glioblastoma patient-derived xenografts (PDX) through orthotopic engraftment of therapy naïve PDX in athymic nude mice, and repeated in vivo exposure to the therapeutic modalities most often used in treating glioblastoma patients: radiotherapy and temozolomide chemotherapy. Post-temozolomide PDX became enriched for C>T transition mutations, acquired inactivating mutations in DNA mismatch repair genes (especially MSH6), and developed hypermutation. Such post-temozolomide PDX were resistant to additional temozolomide (median survival decrease from 80 days in parental PDX to 42 days in a temozolomide-resistant derivative). However, temozolomide-resistant PDX were sensitive to lomustine (also known as CCNU), a nitrosourea which induces tumor cell apoptosis by a different mechanism than temozolomide. These PDX models mimic changes observed in recurrent GBM in patients, including critical features of therapy-driven tumor evolution. These models can therefore serve as valuable tools for improving our understanding and treatment of recurrent glioma

Supplementary Figure S3 from Paclitaxel and Carboplatin in Combination with Low-intensity Pulsed Ultrasound for Glioblastoma

Supplementary Figure 3. Paclitaxel and carboplatin exhibit synergy in vitro. (A) Dose-response matrices illustrating the Loewe synergy score calculated for 11 glioma cell lines at clinically relevant PTX and CBDCA concentrations. (B) Bar charts showing the viability of cell lines treated with PTX, CBDCA, or a combination of both drugs at concentration that showed the highest synergy.</p

Supplementary Table S2 from Paclitaxel and Carboplatin in Combination with Low-intensity Pulsed Ultrasound for Glioblastoma

Supplementary table 2: Table illustrating the representativeness of our study participants.</p

Supplementary Table S1 from Paclitaxel and Carboplatin in Combination with Low-intensity Pulsed Ultrasound for Glioblastoma

Supplementary table 1. Genotype of glioma cell lines used.</p

Supplementary Figure S2 from Paclitaxel and Carboplatin in Combination with Low-intensity Pulsed Ultrasound for Glioblastoma

Supplementary Figure 2. Human glioma cell lines exhibit variable responses to paclitaxel and carboplatin.  (A) Dose-response curves showing the response to PTX (blue) and CBDCA (red) in human cell lines. (B) Bar chart showing the maximal efficacy (Emax) of PTX and CBDCA against human glioma cell lines. </p

Supplementary Methods S1 from Paclitaxel and Carboplatin in Combination with Low-intensity Pulsed Ultrasound for Glioblastoma

Supplementary Material and Methods</p

Supplementary Figure S1 from Paclitaxel and Carboplatin in Combination with Low-intensity Pulsed Ultrasound for Glioblastoma

Supplementary Figure 1. Paclitaxel delivered with low-intensity pulsed ultrasound and microbubbles leads to variable local tumor control.  Coronal T1 with contrast MRI images of patients from our phase I clinical trial (NCT04528680) who received the highest dose of Abraxane (260 mg/m2). We illustrate in green the area covered by the sonication, and observe a variable local tumor control within this region. The five patients presented in the upper (blue) panel exhibited tumor control, while the remaining patients (in red) had tumor growth while on therapy.</p

Prognostic and Predictive Biomarkers in Patients with Metastatic Colorectal Cancer Receiving Regorafenib

Regorafenib is a tyrosine kinase inhibitor approved by the FDA for the treatment of patients with chemotherapy refractory metastatic colorectal cancer (mCRC). Regorafenib inhibits signaling through multiple receptors associated with angiogenesis, metastasis, and tumor immunity. Here, we report biomarker results from LCCC1029, a randomized, placebo-controlled, phase II trial of chemotherapy +/- regorafenib in patients with second-line mCRC. Apanel of 20 soluble protein biomarkers (termed the Angiome) was assessed in the plasma of 149 patients from the LCCC1029 trial both at baseline and along the treatment continuum. Baseline protein levels were analyzed for prognostic and predictive value for progression-free survival (PFS) and overall survival (OS). Changes in protein levels during treatment were analyzed for potential pharmacodynamic effects. Six markers (HGF, IL6, PlGF, VEGF-R1, OPN, and IL6R) were found to be prognostic for PFS. Nine markers (IL6, TIMP-1, PlGF, VCAM-1, ICAM-1, OPN, TSP-2, HGF, and VEGF-R1) were prognostic for OS. Higher baseline levels of OPN (Pintx = 0.0167), VCAM-1 (Pintx = 0.0216), and PDGF-AA (Pintx = 0.0435) appeared to predict for PFS benefit from regorafenib compared with placebo. VCAM-1 was also potentially predictive of OS benefit from regorafenib compared with placebo (Pintx = 0.0124). On-treatment changes of six markers reflected potential on-target effect of regorafenib. Consistent results were observed in an Italian cohort where 105 patients with late-stage mCRC received regorafenib monotherapy. The key findings of this study suggest that VCAM-1 may be a predictive biomarker for regorafenib benefit, while multiple protein markers may be prognostic of outcome in patients with mCRC

Supplementary Figure S4 from Paclitaxel and Carboplatin in Combination with Low-intensity Pulsed Ultrasound for Glioblastoma

Supplementary Figure 4.  Paclitaxel and carboplatin combination lead to cell cycle arrest in the S and G2/M phases. Results of flow cytometric analysis of synchronized GBM6 and MES83 cells that received PTX, CBDCA, or a combination of both drugs for 24 or 48 hours. On the right, we show the proportion of cells arrested at each of the SubG1, G0/G1, S, and G2/M phases.</p