Chemo-Predictive Assay for Targeting Cancer Stem-Like Cells in Patients Affected by Brain Tumors

Abstract

Administration of ineffective anticancer therapy is associated with unnecessary toxicity and development of resistant clones. Cancer stem-like cells (CSLCs) resist chemotherapy, thereby causing relapse of the disease. Thus, development of a test that identifies the most effective chemotherapy management offers great promise for individualized anticancer treatments. We have developed an ex vivo chemotherapy sensitivity assay (ChemoID), which measures the sensitivity of CSLCs as well as the bulk of tumor cells to a variety of chemotherapy agents. Two patients, a 21-year old male (patient 1) and a 5-month female (patient 2), affected by anaplastic WHO grade-III ependymoma were screened using the ChemoID assay. Patient 1 was found sensitive to the combination of irinotecan and bevacizumab, which resulted in a prolonged disease progression free period of 18 months. Following recurrence, the combination of various chemotherapy drugs was tested again with the ChemoID assay. We found that benzyl isothiocyanate (BITC) greatly increased the chemosensitivity of the ependymoma cells to the combination of irinotecan and bevacizumab. After patient 1 was treated for two months with irinotecan, bevacizumab and supplements of cruciferous vegetable extracts containing BITC, we observed over 50% tumoral regression in comparison with pre-ChemoID scan as evidenced by MRI. Patient 2 was found resistant to all treatments tested and following 6 cycles of vincristine, carboplatin, cyclophosphamide, etoposide, and cisplatin in various combinations, the tumor of this patient rapidly progressed and proton beam therapy was recommended. As expected animal studies conducted with patient derived xenografts treated with ChemoID screened drugs recapitulated the clinical observation. This assay demonstrates that patients with the same histological stage and grade of cancer may vary considerably in their clinical response, suggesting that ChemoID testing which measures the sensitivity of CSLCs as well as the bulk of tumor cells to a variety of chemotherapy agents could lead to more effective and personalized anticancer treatments in the future.

Efficacy of ChemoID® guided drug selection for palliative chemotherapy in advanced recurrent high-grade ovarian adenocarcinoma: Case study

“…Our recent clinical studies showed that patient derived CSCs from primary cancer cell cultures can be used in a drug response assay. 9,[30][31][32][33][34][35][36] We have optimized the enrichment of CSCs from tumor biopsies and have developed the ChemoID ® chemotherapy response assay, which measures the sensitivity of CSCs and bulk of tumor cells to chemotherapy to determine the most effective combination of anticancer drugs for solid tumors. 9,[30][31][32][33][34][35][36] …”

“…9,[30][31][32][33][34]36 In brief, primary cultures were initiated by spinning down the malignant cells present in the ascites aspirate and by culturing the cells to sub confluence in RPMI-1640 medium supplemented with 5% irradiated, heat inactivated, defined fetal bovine serum (Thermofisher/Hyclone), and 50 U of penicillin and 5 µg of streptomycin/mL of medium (Thermofisher/Mediatech). Proliferation of CSCs was obtained using a culture methodology previously described 9,31 in which culture media, oxygenation, rotational speed of the culture vessel, temperature and CO2 were kept consistently constant for seven days. Cells were then removed and counted using trypan blue exclusion to determine cellular viability and cell number.…”

“…The WST8 assay was performed 48-hours following chemotherapy treatment to assess cell viability as previously described. 9 The inhibition of bulk of tumor cells and CSCs survival was measured for each concentration (average counts in five replicates ± SE) of a given treatment. The survival of tumor cells at each concentration was calculated as compared to control-2 and overall percent of bulk and CSC tumor cells killed were calculated for each treatment as the primary measures of potential therapy efficacy.…”

“…7,8 The ability to choose the most effective chemotherapy may help improving patients' quality of life by avoiding the physical, emotional, and financial burden of ineffective therapy. 9 Anticancer drugs for different reasons have a high rate of failure and cell culture chemotherapy testing has been used during the recent past to identify which drugs are more likely to be effective especially against those of gynecological origin. 10,11 Many attempts have been made over the years to develop an in-vitro anti-cancer test that can provide clinically relevant treatment information.…”

Analysis of chemo-predictive assay for targeting cancer stem cells in 41 glioblastoma patients.

“…However, until now, this approach has been hampered by the chemotherapy testing only being performed on bulk of tumor cells derived from cancer biopsies [8][9][10][11][12][13][14][15][16][17]. GBMs contain a heterogeneous population of cells, among which is a population of self-renewing cancer stem cells (CSCs) that contribute to tumorigenesis, treatment resistance, and tumor recurrence [3,6].…”