Introduction: Limited stage small cell lung cancer (LS-SCLC) is treated with standard of care pla... more Introduction: Limited stage small cell lung cancer (LS-SCLC) is treated with standard of care platinum/etoposide (EP) and thoracic radiation therapy (TRT) with curative intent, however the majority of patients are not cured and median overall survival is approximately 30 months. Addition of atezolizumab to chemotherapy in extensive stage SCLC has improved progression free and overall survival in a non-curative setting leading to hope that addition of an immune checkpoint inhibitor to standard chemoradiotherapy could benefit LS-SCLC patients. LU005 is a randomized phase II/III trial of standard concurrent chemoradiation with or without atezolizumab for patients with LS-SCLC. Methods: Patients are randomly assigned in a 1:1 ratio to standard EP chemotherapy with concurrent TRT (45 Gy BID or 66 Gy QD) with or without atezolizumab beginning concurrently with TRT, and continued every 3 weeks for up to 12 months. Eligible patients have LS-SCLC, PS 0-2, adequate organ function, no concerning comorbidities (including no active autoimmune disease) and are eligible for TRT. Patients are randomized prior to their second cycle of EP and thoracic radiation begins with the second overall cycle of chemotherapy (first cycle of study therapy) in both treatment arms. Prophylactic cranial radiation (PCI) is recommended for patients who respond to treatment. The phase II/III primary endpoints are progression free (PFS) and overall survival (OS) respectively. Secondary endpoints include objective response rates, local and distant disease control, and quality of life/patient reported outcomes assessment. Translational science component includes blood and tissue based immune related assays. Results: This study activated in May 2019. 120 of 506 planned patients have been accrued as of 8/20/2020
Highlights d The MMB-FOXM1 complex components are required for CHK1i sensitivity d CHK1i prematur... more Highlights d The MMB-FOXM1 complex components are required for CHK1i sensitivity d CHK1i prematurely activates the G2/M transcriptional program by MMB-FOXM1 d Mitotic pH3 induced by CHK1i during S phase requires the MMB-FOXM1 complex d Premature mitosis is required for replication catastrophe after CHK1 inhibition
8513 Background: A minority of the approximately 40,000 US patients diagnosed annually with stage... more 8513 Background: A minority of the approximately 40,000 US patients diagnosed annually with stage III NSCLC can be cured by concurrent CRT. Standard adjuvant immune checkpoint inhibitors (ICI) improve outcome for those patients who complete CRT with good performance status (PS) and without disease progression, but most patients diagnosed with unresectable stage III NSCLC will not meet the criteria for adjuvant ICI. AFT-16 investigated safety and efficacy of neoadjuvant and adjuvant atezolizumab as a strategy that may allow more patients to benefit from ICI. Methods: Eligible patients received 4 cycles (cy) of atezolizumab 1200 mg IV q 21 days followed by CRT with 60 Gy + weekly carboplatin and paclitaxel (CP), CP consolidation and adjuvant atezolizumab to complete 1 year of therapy (17 cy). The primary endpoint of disease control rate at 12 weeks (wks) has been reported. Secondary endpoints reported here include overall response rate, safety, and progression-free and overall surviva...
TPS8585Background: Over 40,000 patients in the US/year are diagnosed with stage III NSCLC, but on... more TPS8585Background: Over 40,000 patients in the US/year are diagnosed with stage III NSCLC, but only ~25% will be cured by standard chemoradiation (CRT). Combining checkpoint inhibition through PD-L...
Data availability All data presented in this manuscript are available from the corresponding auth... more Data availability All data presented in this manuscript are available from the corresponding author upon reasonable request. Bulk tumour cell RNA sequencing has been deposited at the Gene Expression Omnibus (GEO) under accession number https://www.ncbi.nlm.nih.gov/geo/ query/acc.cgi?acc=GSE110708. Single-cell RNA sequencing of tumour cells were also deposited at the GEO under accession numberhttps://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE110746.
International Journal of Radiation Oncology*Biology*Physics, 2018
lung tumor was the 2-h SUVmax minus the 1-h SUVmax. The retention index (RI) was calculated by di... more lung tumor was the 2-h SUVmax minus the 1-h SUVmax. The retention index (RI) was calculated by dividing the increase in the 2-h SUVmax by the 1-h SUVmax. Immunohistochemical studies of glucose transporter 1 (GLUT-1) and hexokinase 2 (HK-2) on the paraffin-embedded pre-treatment tumor samples were performed. Correlations of metabolic markers with parameters extracted from dual-phase FDG-PET and patient survivals were analyzed. Results: Expressions of GLUT-1 and HK-2 were positively correlated in lung tumors (P< 0.001). The SUVinc > 1 and RI > 15% had the best discriminative yield for disease-free survival (DFS). High-level expressions of both GLUT-1 and HK-2 were significantly correlated with SUVinc > 1 (all P< 0.01). However, neither GLUT-1 nor HK-2 expressions were significantly correlated with higher RI (PZ 0.26 and 0.40, respectively). Both GLUT-1 and HK-2 were prognostic factors and associated with poor survival in NSCLC patients. Patients with co-overexpression of GLUT-1 and HK-2 had the worst DFS (P Z 0.002). Conclusion: High-level expressions of both GLUT-1 and HK-2 are significantly correlated with the increment of SUV but not RI on dualphase FGD PET. GLUT-1 and HK-2 are prognostic markers in NSCLC.
International Journal of Radiation Oncology*Biology*Physics, 2016
Previous phase II data showed a benefit to dose escalated therapy for locally-advanced non-small ... more Previous phase II data showed a benefit to dose escalated therapy for locally-advanced non-small cell lung cancer (NSCLC). Given our previous practice with dose escalated therapy, we sought to determine factors associated with morbidity and outcomes. Materials/Methods: We retrospectively reviewed 170 patients between 2001 and 2013 with stage IIIA and B NSCLC treated with definitive intent. Median dose given was 72 Gy (54-84). Intensity-modulated radiation therapy (IMRT) was used in 27.1%. All patients received a 4D-CT simulation scan and were gated if tumor movement was larger than 5mm. Overall survival (OS), locoregional control (LRC), and freedom from distant metastasis (FFDM) were calculated using log rank and Cox regression analysis. We also evaluated dosimetric parameters associated with survival and morbidity. Results: Median follow-up the entire cohort was 22 months and 36.6 months for patients still living. The median survival was 27.4 months yielding a 2-and 4-year OS of 56.0 and 30.7%, respectively. On univariate analysis, clinical stage IIIB (PZ0.037), larger PTV (P<0.001), higher heart V 30 (PZ0.048), and higher esophageal mean dose (PZ0.024), V 5 (PZ0.015) and V 60 (PZ0.011) were associated with worse survival. However, on multivariable analysis, only PTV above 450cc (52.2 vs. 25.3 months, P<0.001) and esophageal V 60 >20% (43.8 vs. 21.3 months, PZ0.01) was associated with lower survival. The 2-and 4-year LRC was 54.4% and 43.9%, respectively. The 2-and 4-year FFDM was 54.4% and 40.7%, respectively. No OS (PZ0.586), LRC (PZ0.440), or FFDM (PZ0.230) benefit was associated with doses above 66Gy. Acute grade 2 or higher lung toxicity and esophagitis took place in 9.5% and 59.7% of our cohort, respectively. Late grade 3+ toxicities included esophagitis (2year estimate 6.5%) and pneumonitis (2-year estimate 2.1%). Acute grade 2 or higher lung toxicity was lower in the lung V 5 65 group (7.4% vs. 23.8%, PZ0.03) and acute grade 2 or higher esophagitis was lower in the V 60 20% group (62% vs 81.3%, PZ0.018). IMRT use was higher in IIIB than IIIA (56.5 %vs 39.5%, PZ0.048) and was associated with a higher lung V 5 and V 10. Conclusion: Our outcomes with advanced staged NSCLC are consistent with the results published in the modern era. No benefit to higher doses is consistent with RTOG 0617. Maintaining low esophageal V 60 was associated with a lower morbidity and mortality and low lung V 5 was associated with lower lung toxicity.
International Journal of Radiation Oncology*Biology*Physics, 2014
squamous cell carcinoma (SCC, 24%) or suspicious on imaging but not histologically confirmed (37%... more squamous cell carcinoma (SCC, 24%) or suspicious on imaging but not histologically confirmed (37%). Pts were typically treated to 50 Gy in 4 (peripheral) or 5 (central) fractions. At 2 years, LC was 97%. LC did not differ by tumor location, fractionation or pt characteristics (all p>0.05) but trended lower for SCC (p Z 0.06). LC was better for T1aT1b than T2a (p Z 0.05). Nodal and distant failure, cancer-specific survival (CSS) and OS did not differ by T stage (all p>0.05). Overall, 21% had locoregional failure. Operable pts refusing surgery had similar LC (100% vs 96%, p Z 0.28), nodal (7% vs 14%, p Z 0.33) and distant (7% vs 4%, p Z 0.45) failure, and CSS (96% vs 96%, p Z 0.86), although they trended to better 2-year (85% vs 69%, p Z 0.09) and median (not reached vs 34 months, p Z 0.12) OS than inoperable pts. Outcomes were similar with or without pathologic confirmation (LC p Z 0.64, OS p Z 0.43). Grade 2 rib fracture occurred in 1%, chest wall syndrome 6% and pneumonitis 3%. Lung mean dose (p Z 0.06) and V20 (p Z 0.08) trended toward pneumonitis association. No grade >2 acute or late toxicity was observed. Conclusions: This study showed SBRT is well tolerated and can achieve high LC. LC was less for tumors >3 cm but did not differ by tumor location or fractionation, likely since all regimens were BED >100. Nodal and distant failures were limited, likely due to pre-SBRT universal PET/CT staging and often pathologic nodal staging. Although LC and CSS were similar for operable and inoperable pts, inoperable pts had somewhat lower OS, likely due to greater comorbidities. Mature prospective data from RTOG 0618 and JCOG 0403 are needed to better assess SBRT in operable pts. Author Disclosure: C.B. Simone: None. M. Heskel: None. E.P. Xanthopoulos: None. M.N. Corradetti: None. S. Singhal: None. J.S. Friedberg: None. T.T. Pechet: None. J.C. Kucharczuk: None. J.P. Christodouleas: None.W. Levin: None. K.A. Cengel: None. R. Rengan: None. S.M. Hahn: None.
INTRODUCTION: Recent evidence suggests that glioblastoma is driven by a subset of tumor initiatin... more INTRODUCTION: Recent evidence suggests that glioblastoma is driven by a subset of tumor initiating (TI) cells characterized by their capacity to form tumors in xenograft models and self-renew in vitro. These TI cells share many properties of neural stem/progenitor cells, including the expression of certain cell surface markers. With serial passage, many cells lose their capacity to TI. The transition between TI-proficient and-deficient states remains poorly understood. METHODS AND RESULTS: There are two theoretic models for the maintenance of TI states. In the "elite" model, TI activity is restricted to a predetermined subpopulation of cells. The alternative "stochastic" model suggests that any tumor cell has a finite chance of acquiring TI capacity through random fluctuations in cell physiology. To address this issue, we examined the TI capacity of distinct subclones isolated from a distinct glioblastoma line as well as the TI capacity of single cells derived from each distinct clone. We found that only a subset of subclones from a single glioblastoma line displayed capacity for TI, suggestive of the elite model. However, single cells derived from any single subclone exhibited a wide range of TI capacity, suggesting a stochastic component to this process. Transcriptome profiling of the subclones of differing TI revealed a gene signature associated with TI capacity. Analysis of this signature showed enrichment for genes regulated by c-Myc. Indeed, clones with increased TI capacity tend to harbor increased c-Myc expression. Additionally, over-expression of c-myc increased the TI capacity of glioblastoma cells in xenograft models and led to the formation of intracranial tumor in an Ink4a/ARF null transgenic murine model. CONCLUSION: Our results are most consistent with a threshold model in which TI states in glioblastomas are driven by expression levels of critical factors such as c-Myc.
OBJECTIVE: Despite the standard regimen of maximal resection followed by concurrent ionizing radi... more OBJECTIVE: Despite the standard regimen of maximal resection followed by concurrent ionizing radiation (IR) and temozolomide (TMZ), long-term survivors of patients afflicted with glioblastoma (GBM) remain rare. We sought to identify molecular determinants of resistance to these agents using a combined functional genomic and bioinformatic approach. METHODS: Parallel RNAi screens were performed to identify gene silencings that modulate IR and TMZ resistance. A viability-based screen was performed in multiple glioma lines with the Hannon-Elledge library of 74,705 short hairpin RNAs targeting nearly all human genes. A focused screen was also performed to identify modulators of the Fanconi Anemia (FA)/BRCA pathway, a pathway we previously identified as a determinant of IR and TMZ resistance. The most promising candidates were confirmed by independent RNAi and pharmacologic inhibition in vitro and in vivo xenografts. Correlations between relative expression levels of the candidate genes a...
Highlights d Genome-wide CRISPR screen identifies determinants of ATM inhibitor sensitivity d Los... more Highlights d Genome-wide CRISPR screen identifies determinants of ATM inhibitor sensitivity d Loss of Fanconi anemia (FA) pathway and ATM is synthetic lethal d ATM is required in FA-deficient cells to promote DNA end resection and HR repair d Loss of FA pathway and ATM results in accumulation of toxic levels of NHEJ
Introduction: Limited stage small cell lung cancer (LS-SCLC) is treated with standard of care pla... more Introduction: Limited stage small cell lung cancer (LS-SCLC) is treated with standard of care platinum/etoposide (EP) and thoracic radiation therapy (TRT) with curative intent, however the majority of patients are not cured and median overall survival is approximately 30 months. Addition of atezolizumab to chemotherapy in extensive stage SCLC has improved progression free and overall survival in a non-curative setting leading to hope that addition of an immune checkpoint inhibitor to standard chemoradiotherapy could benefit LS-SCLC patients. LU005 is a randomized phase II/III trial of standard concurrent chemoradiation with or without atezolizumab for patients with LS-SCLC. Methods: Patients are randomly assigned in a 1:1 ratio to standard EP chemotherapy with concurrent TRT (45 Gy BID or 66 Gy QD) with or without atezolizumab beginning concurrently with TRT, and continued every 3 weeks for up to 12 months. Eligible patients have LS-SCLC, PS 0-2, adequate organ function, no concerning comorbidities (including no active autoimmune disease) and are eligible for TRT. Patients are randomized prior to their second cycle of EP and thoracic radiation begins with the second overall cycle of chemotherapy (first cycle of study therapy) in both treatment arms. Prophylactic cranial radiation (PCI) is recommended for patients who respond to treatment. The phase II/III primary endpoints are progression free (PFS) and overall survival (OS) respectively. Secondary endpoints include objective response rates, local and distant disease control, and quality of life/patient reported outcomes assessment. Translational science component includes blood and tissue based immune related assays. Results: This study activated in May 2019. 120 of 506 planned patients have been accrued as of 8/20/2020
Highlights d The MMB-FOXM1 complex components are required for CHK1i sensitivity d CHK1i prematur... more Highlights d The MMB-FOXM1 complex components are required for CHK1i sensitivity d CHK1i prematurely activates the G2/M transcriptional program by MMB-FOXM1 d Mitotic pH3 induced by CHK1i during S phase requires the MMB-FOXM1 complex d Premature mitosis is required for replication catastrophe after CHK1 inhibition
8513 Background: A minority of the approximately 40,000 US patients diagnosed annually with stage... more 8513 Background: A minority of the approximately 40,000 US patients diagnosed annually with stage III NSCLC can be cured by concurrent CRT. Standard adjuvant immune checkpoint inhibitors (ICI) improve outcome for those patients who complete CRT with good performance status (PS) and without disease progression, but most patients diagnosed with unresectable stage III NSCLC will not meet the criteria for adjuvant ICI. AFT-16 investigated safety and efficacy of neoadjuvant and adjuvant atezolizumab as a strategy that may allow more patients to benefit from ICI. Methods: Eligible patients received 4 cycles (cy) of atezolizumab 1200 mg IV q 21 days followed by CRT with 60 Gy + weekly carboplatin and paclitaxel (CP), CP consolidation and adjuvant atezolizumab to complete 1 year of therapy (17 cy). The primary endpoint of disease control rate at 12 weeks (wks) has been reported. Secondary endpoints reported here include overall response rate, safety, and progression-free and overall surviva...
TPS8585Background: Over 40,000 patients in the US/year are diagnosed with stage III NSCLC, but on... more TPS8585Background: Over 40,000 patients in the US/year are diagnosed with stage III NSCLC, but only ~25% will be cured by standard chemoradiation (CRT). Combining checkpoint inhibition through PD-L...
Data availability All data presented in this manuscript are available from the corresponding auth... more Data availability All data presented in this manuscript are available from the corresponding author upon reasonable request. Bulk tumour cell RNA sequencing has been deposited at the Gene Expression Omnibus (GEO) under accession number https://www.ncbi.nlm.nih.gov/geo/ query/acc.cgi?acc=GSE110708. Single-cell RNA sequencing of tumour cells were also deposited at the GEO under accession numberhttps://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE110746.
International Journal of Radiation Oncology*Biology*Physics, 2018
lung tumor was the 2-h SUVmax minus the 1-h SUVmax. The retention index (RI) was calculated by di... more lung tumor was the 2-h SUVmax minus the 1-h SUVmax. The retention index (RI) was calculated by dividing the increase in the 2-h SUVmax by the 1-h SUVmax. Immunohistochemical studies of glucose transporter 1 (GLUT-1) and hexokinase 2 (HK-2) on the paraffin-embedded pre-treatment tumor samples were performed. Correlations of metabolic markers with parameters extracted from dual-phase FDG-PET and patient survivals were analyzed. Results: Expressions of GLUT-1 and HK-2 were positively correlated in lung tumors (P< 0.001). The SUVinc > 1 and RI > 15% had the best discriminative yield for disease-free survival (DFS). High-level expressions of both GLUT-1 and HK-2 were significantly correlated with SUVinc > 1 (all P< 0.01). However, neither GLUT-1 nor HK-2 expressions were significantly correlated with higher RI (PZ 0.26 and 0.40, respectively). Both GLUT-1 and HK-2 were prognostic factors and associated with poor survival in NSCLC patients. Patients with co-overexpression of GLUT-1 and HK-2 had the worst DFS (P Z 0.002). Conclusion: High-level expressions of both GLUT-1 and HK-2 are significantly correlated with the increment of SUV but not RI on dualphase FGD PET. GLUT-1 and HK-2 are prognostic markers in NSCLC.
International Journal of Radiation Oncology*Biology*Physics, 2016
Previous phase II data showed a benefit to dose escalated therapy for locally-advanced non-small ... more Previous phase II data showed a benefit to dose escalated therapy for locally-advanced non-small cell lung cancer (NSCLC). Given our previous practice with dose escalated therapy, we sought to determine factors associated with morbidity and outcomes. Materials/Methods: We retrospectively reviewed 170 patients between 2001 and 2013 with stage IIIA and B NSCLC treated with definitive intent. Median dose given was 72 Gy (54-84). Intensity-modulated radiation therapy (IMRT) was used in 27.1%. All patients received a 4D-CT simulation scan and were gated if tumor movement was larger than 5mm. Overall survival (OS), locoregional control (LRC), and freedom from distant metastasis (FFDM) were calculated using log rank and Cox regression analysis. We also evaluated dosimetric parameters associated with survival and morbidity. Results: Median follow-up the entire cohort was 22 months and 36.6 months for patients still living. The median survival was 27.4 months yielding a 2-and 4-year OS of 56.0 and 30.7%, respectively. On univariate analysis, clinical stage IIIB (PZ0.037), larger PTV (P<0.001), higher heart V 30 (PZ0.048), and higher esophageal mean dose (PZ0.024), V 5 (PZ0.015) and V 60 (PZ0.011) were associated with worse survival. However, on multivariable analysis, only PTV above 450cc (52.2 vs. 25.3 months, P<0.001) and esophageal V 60 >20% (43.8 vs. 21.3 months, PZ0.01) was associated with lower survival. The 2-and 4-year LRC was 54.4% and 43.9%, respectively. The 2-and 4-year FFDM was 54.4% and 40.7%, respectively. No OS (PZ0.586), LRC (PZ0.440), or FFDM (PZ0.230) benefit was associated with doses above 66Gy. Acute grade 2 or higher lung toxicity and esophagitis took place in 9.5% and 59.7% of our cohort, respectively. Late grade 3+ toxicities included esophagitis (2year estimate 6.5%) and pneumonitis (2-year estimate 2.1%). Acute grade 2 or higher lung toxicity was lower in the lung V 5 65 group (7.4% vs. 23.8%, PZ0.03) and acute grade 2 or higher esophagitis was lower in the V 60 20% group (62% vs 81.3%, PZ0.018). IMRT use was higher in IIIB than IIIA (56.5 %vs 39.5%, PZ0.048) and was associated with a higher lung V 5 and V 10. Conclusion: Our outcomes with advanced staged NSCLC are consistent with the results published in the modern era. No benefit to higher doses is consistent with RTOG 0617. Maintaining low esophageal V 60 was associated with a lower morbidity and mortality and low lung V 5 was associated with lower lung toxicity.
International Journal of Radiation Oncology*Biology*Physics, 2014
squamous cell carcinoma (SCC, 24%) or suspicious on imaging but not histologically confirmed (37%... more squamous cell carcinoma (SCC, 24%) or suspicious on imaging but not histologically confirmed (37%). Pts were typically treated to 50 Gy in 4 (peripheral) or 5 (central) fractions. At 2 years, LC was 97%. LC did not differ by tumor location, fractionation or pt characteristics (all p>0.05) but trended lower for SCC (p Z 0.06). LC was better for T1aT1b than T2a (p Z 0.05). Nodal and distant failure, cancer-specific survival (CSS) and OS did not differ by T stage (all p>0.05). Overall, 21% had locoregional failure. Operable pts refusing surgery had similar LC (100% vs 96%, p Z 0.28), nodal (7% vs 14%, p Z 0.33) and distant (7% vs 4%, p Z 0.45) failure, and CSS (96% vs 96%, p Z 0.86), although they trended to better 2-year (85% vs 69%, p Z 0.09) and median (not reached vs 34 months, p Z 0.12) OS than inoperable pts. Outcomes were similar with or without pathologic confirmation (LC p Z 0.64, OS p Z 0.43). Grade 2 rib fracture occurred in 1%, chest wall syndrome 6% and pneumonitis 3%. Lung mean dose (p Z 0.06) and V20 (p Z 0.08) trended toward pneumonitis association. No grade >2 acute or late toxicity was observed. Conclusions: This study showed SBRT is well tolerated and can achieve high LC. LC was less for tumors >3 cm but did not differ by tumor location or fractionation, likely since all regimens were BED >100. Nodal and distant failures were limited, likely due to pre-SBRT universal PET/CT staging and often pathologic nodal staging. Although LC and CSS were similar for operable and inoperable pts, inoperable pts had somewhat lower OS, likely due to greater comorbidities. Mature prospective data from RTOG 0618 and JCOG 0403 are needed to better assess SBRT in operable pts. Author Disclosure: C.B. Simone: None. M. Heskel: None. E.P. Xanthopoulos: None. M.N. Corradetti: None. S. Singhal: None. J.S. Friedberg: None. T.T. Pechet: None. J.C. Kucharczuk: None. J.P. Christodouleas: None.W. Levin: None. K.A. Cengel: None. R. Rengan: None. S.M. Hahn: None.
INTRODUCTION: Recent evidence suggests that glioblastoma is driven by a subset of tumor initiatin... more INTRODUCTION: Recent evidence suggests that glioblastoma is driven by a subset of tumor initiating (TI) cells characterized by their capacity to form tumors in xenograft models and self-renew in vitro. These TI cells share many properties of neural stem/progenitor cells, including the expression of certain cell surface markers. With serial passage, many cells lose their capacity to TI. The transition between TI-proficient and-deficient states remains poorly understood. METHODS AND RESULTS: There are two theoretic models for the maintenance of TI states. In the "elite" model, TI activity is restricted to a predetermined subpopulation of cells. The alternative "stochastic" model suggests that any tumor cell has a finite chance of acquiring TI capacity through random fluctuations in cell physiology. To address this issue, we examined the TI capacity of distinct subclones isolated from a distinct glioblastoma line as well as the TI capacity of single cells derived from each distinct clone. We found that only a subset of subclones from a single glioblastoma line displayed capacity for TI, suggestive of the elite model. However, single cells derived from any single subclone exhibited a wide range of TI capacity, suggesting a stochastic component to this process. Transcriptome profiling of the subclones of differing TI revealed a gene signature associated with TI capacity. Analysis of this signature showed enrichment for genes regulated by c-Myc. Indeed, clones with increased TI capacity tend to harbor increased c-Myc expression. Additionally, over-expression of c-myc increased the TI capacity of glioblastoma cells in xenograft models and led to the formation of intracranial tumor in an Ink4a/ARF null transgenic murine model. CONCLUSION: Our results are most consistent with a threshold model in which TI states in glioblastomas are driven by expression levels of critical factors such as c-Myc.
OBJECTIVE: Despite the standard regimen of maximal resection followed by concurrent ionizing radi... more OBJECTIVE: Despite the standard regimen of maximal resection followed by concurrent ionizing radiation (IR) and temozolomide (TMZ), long-term survivors of patients afflicted with glioblastoma (GBM) remain rare. We sought to identify molecular determinants of resistance to these agents using a combined functional genomic and bioinformatic approach. METHODS: Parallel RNAi screens were performed to identify gene silencings that modulate IR and TMZ resistance. A viability-based screen was performed in multiple glioma lines with the Hannon-Elledge library of 74,705 short hairpin RNAs targeting nearly all human genes. A focused screen was also performed to identify modulators of the Fanconi Anemia (FA)/BRCA pathway, a pathway we previously identified as a determinant of IR and TMZ resistance. The most promising candidates were confirmed by independent RNAi and pharmacologic inhibition in vitro and in vivo xenografts. Correlations between relative expression levels of the candidate genes a...
Highlights d Genome-wide CRISPR screen identifies determinants of ATM inhibitor sensitivity d Los... more Highlights d Genome-wide CRISPR screen identifies determinants of ATM inhibitor sensitivity d Loss of Fanconi anemia (FA) pathway and ATM is synthetic lethal d ATM is required in FA-deficient cells to promote DNA end resection and HR repair d Loss of FA pathway and ATM results in accumulation of toxic levels of NHEJ
Uploads
Papers by David Kozono