Elevated glycolysis is a common metabolic trait of cancer, but what drives such metabolic reprogramming remains incompletely clear. We report here a novel transcriptional repressor-mediated negative ...regulation of glycolysis. ZBTB7A, a member of the POK (POZ/BTB and Krüppel) transcription repressor family, directly binds to the promoter and represses the transcription of critical glycolytic genes, including GLUT3, PFKP, and PKM. Analysis of The Cancer Genome Atlas (TCGA) data sets reveals that the ZBTB7A locus is frequently deleted in many human tumors. Significantly, reduced ZBTB7A expression correlates with up-regulation of the glycolytic genes and poor survival in colon cancer patients. Remarkably, while ZBTB7A-deficient tumors progress exceedingly fast, they exhibit an unusually heightened sensitivity to glycolysis inhibition. Our study uncovers a novel tumor suppressor role of ZBTB7A in directly suppressing glycolysis.
Metastatic colorectal cancer frequently occurs in elderly patients. Bevacizumab in combination with front line chemotherapy (CT) is a standard treatment but some concern raised about tolerance of ...bevacizumab for these patients. The purpose of PRODIGE 20 was to evaluate tolerance and efficacy of bevacizumab according to specific end points in this population.
Patients aged 75 years and over were randomly assigned to bevacizumab + CT (BEV) versus CT. LV5FU2, FOLFOX and FOLFIRI regimen were prescribed according to investigator’s choice. The composite co-primary end point, assessed 4 months after randomization, was based on efficacy (tumor control and absence of decrease of the Spitzer QoL index) and safety (absence of severe cardiovascular toxicities and unexpected hospitalization). For each arm, the treatment will be consider as inefficient if 20% or less of the patients met the efficacy criteria and not safe if 40% or less met the safety criteria.
About 102 patients were randomized (51 BEV and 51 CT), median age was 80 years (range 75–91). Primary end point was met for efficacy in 50% and 58% and for safety in 61% and 71% of patients in BEV and CT, respectively. Median progression-free survival was 9.7 months in BEV and 7.8 months in CT. Median overall survival was 21.7 months in BEV and 19.8 months in CT. The 36-month overall survival rate was 27% in BEV and 10.1% in CT. Severe toxicities grade 3/4 were mainly non-hematologic toxicities (80.4% in BEV, 63.3% in CT).
Bevacizumab combined with CT was safe and efficient. Both arms met the primary safety and efficacy criteria.
The p300 and CBP histone acetyltransferases are recruited to DNA double-strand break (DSB) sites where they induce histone acetylation, thereby influencing the chromatin structure and DNA repair ...process. Whether p300/CBP at DSB sites also acetylate non-histone proteins, and how their acetylation affects DSB repair, remain unknown. Here we show that p300/CBP acetylate RAD52, a human homologous recombination (HR) DNA repair protein, at DSB sites. Using in vitro acetylated RAD52, we identified 13 potential acetylation sites in RAD52 by a mass spectrometry analysis. An immunofluorescence microscopy analysis revealed that RAD52 acetylation at DSBs sites is counteracted by SIRT2- and SIRT3-mediated deacetylation, and that non-acetylated RAD52 initially accumulates at DSB sites, but dissociates prematurely from them. In the absence of RAD52 acetylation, RAD51, which plays a central role in HR, also dissociates prematurely from DSB sites, and hence HR is impaired. Furthermore, inhibition of ataxia telangiectasia mutated (ATM) protein by siRNA or inhibitor treatment demonstrated that the acetylation of RAD52 at DSB sites is dependent on the ATM protein kinase activity, through the formation of RAD52, p300/CBP, SIRT2, and SIRT3 foci at DSB sites. Our findings clarify the importance of RAD52 acetylation in HR and its underlying mechanism.
The excessive metastatic propensity of melanoma makes it the most deadly form of skin cancer, yet the underlying mechanism of metastasis remains elusive. Here, mining of cancer genome datasets ...discovered a frequent loss of chromosome 19p13.3 and associated downregulation of the zinc finger transcription factor ZBTB7A in metastatic melanoma. Functional assessment of ZBTB7A-regulated genes identified MCAM, which encodes an adhesion protein key to melanoma metastasis. Using an integrated approach, it is demonstrated that ZBTB7A directly binds to the promoter and transcriptionally represses the expression of MCAM, establishing ZBTB7A as a bona fide transcriptional repressor of MCAM. Consistently, downregulation of ZBTB7A results in marked upregulation of MCAM and enhanced melanoma cell invasion and metastasis. An inverse correlation of ZBTB7A and MCAM expression in association with melanoma metastasis is further validated with data from analysis of human melanoma specimens.
Together, these results uncover a previously unrecognized role of ZBTB7A in negative regulation of melanoma metastasis and have important clinical implications.
Potentially lethal damage (PLD) repair has been defined as that property conferring the ability of cells to recover from DNA damage depending on the postirradiation environment. Using a novel cyclin ...dependent kinase 1 inhibitor RO-3306 to arrest cells in the G2 phase of the cell cycle, examined PLD repair in G2 in cultured Chinese hamster ovary (CHO) cells. Several CHO-derived DNA repair mutant cell lines were used in this study to elucidate the mechanism of DNA double-strand break repair and to examine PLD repair during the G2 phase of the cell cycle. While arrested in G2 phase, wild-type CHO cells displayed significant PLD repair and improved cell survival compared with cells released immediately from G2 after irradiation. Both the radiation-induced chromosomal aberrations and the delayed entry into mitosis were also reduced by G2-holding PLD recovery. The PLD repair observed in G2 was observed in nonhomologous end-joining (NHEJ) mutant cell lines but absent in homologous recombination mutant cell lines. From the survival curves, G2-NHEJ mutant cell lines were found to be very sensitive to gamma-ray exposure when compared to G2/homologous recombination mutant cell lines. Our findings suggest that after exposure to ionizing radiation during G2, NHEJ is responsible for the majority of non-PLD repair, and conversely, that the homologous recombination is responsible for PLD repair in G2.
Older patients have frailty characteristics that impair the transposition of treatment results found in younger patients. Predictive factors are needed to help with treatment choices for older ...patients. The PRODIGE 20 study is a randomized phase II study that evaluated chemotherapy associated with bevacizumab (BEV) or not (CT) in patients aged 75 years or older.
Patients underwent a geriatric assessment at randomization and at each evaluation. The predictive value of geriatric and oncologic factors was determined for the primary composite end-point assessing safety and efficacy of treatment (BEV or CT) simultaneously and also progression-free survival (PFS) and overall survival (OS).
102 patients were randomized (51 BEV and 51 CT; median age 80 years range 75–91). On multivariate analysis, baseline normal independent activity of daily living (IADL) score and no previous cardiovascular disease predicted the primary end-point. High (versus low) baseline Köhne score predicted short PFS and baseline Spitzer quality of life (QoL) score <8, albumin level ≤35 g/L, CA19.9 >2 LN levels above normal and high baseline Köhne score predicted short OS. Survival without deteriorated QoL and autonomy was similar with BEV and CT. On subgroup analyses, the benefit of bevacizumab seemed to be maintained in patients with baseline impaired IADL or nutritional status.
Normal IADL score was associated with a good efficacy and safety of both BEV and CT. Köhne criteria may be relevant prognostic factors in older patients. Adding bevacizumab to chemotherapy does not impair patient autonomy or QoL.
•A normal independent activity of daily living is predictive of efficacy of front line chemotherapy.•Köhne criteria for the first time is validated as a predictor for overall survival in older patients.•Adding bevacizumab to chemotherapy does not impair older patient's autonomy or quality of life.
DNA repair is essential in maintaining genome integrity and defects in different steps of the process have been linked to cancer and aging. It is a long lasting question how DNA repair is spatially ...and temporarily organized in the highly compartmentalized nucleus and whether the diverse nuclear compartments regulate differently the efficiency of repair. Increasing evidence suggest the involvement of nuclear pore complexes in repair of double-strand breaks (DSBs) in yeast. Here, we show that the human nucleoporin 153 (NUP153) has a role in repair of DSBs and in the activation of DNA damage checkpoints. We explore the mechanism of action of NUP153 and we propose its potential as a novel therapeutic target in cancers.
Purpose
Whether an anticoagulant prophylaxis is needed for patients with cancer with a central venous catheter is a highly controversial subject. We designed a study to compare different prophylactic ...strategies over 3 months of treatment.
Methods
We performed a phase III prospective, open-label randomized trial. After the insertion of a central venous access device, consecutive patients with planned chemotherapy for cancer were randomized to no anticoagulant prophylaxis, low molecular weight heparin low molecular weight heparin (LMWH); with isocoagulation doses, or warfarin 1 mg/day. Treatments were given over the first 3 months. Doppler ultrasound and venographies were performed on days 1 and 90, respectively, or sooner in case of clinical presumption of thrombosis.
Results
A total of 420 patients were randomized, and 407 were evaluable. Forty-two catheter-related deep vein thrombosis (DVT) occurred (10.3 %), 20 in those with no anticoagulation, 8 in those receiving warfarin, and 14 in those receiving LMWH. Nine additional non-related catheter deep vein thrombosis (CDVT) occurred. Anticoagulation significantly reduced the incidence of catheter-related DVT (
p
= 0.035) and catheter non-related DVT (
p
= 0.007), with no difference between warfarin and LMWH. Safety was good (3.4 % of attributable events) but compliance with randomized prophylaxis was lower than expected.
Conclusions
Prophylaxis showed a benefit regarding catheter-related and non-catheter-related DVT with no increase in serious side effects.
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