Opposite roles of Rad5 in DNA damage tolerance: playing in both error-free and mutagenic lesion bypass

DNA Damage Tolerance (DDT) funcPons to bypass replicaPon-blocking lesions and is divided into two disPnct pathways: error-prone Translesion Synthesis (TLS) and error-free Damage Avoidance (DA). Rad5 is an important player in these processes. Indeed, Saccharomyces cerevisiae Rad5 is a large mulPfuncPonal protein that contains three well defined domains: a RING domain that promotes PCNA polyubiquiPnaPon and a ssDNA-dependent ATPase/helicase domain, that are both conserved in Rad5 human ortholog HLTF. Yeast Rad5 also contains a Rev1-binding domain. In this study we used domain-specific mutants to address the contribuPon of each of the Rad5 funcPons to lesion tolerance. Using an assay based on the inserPon of a single lesion into a defined locus in the genome of a living yeast cell, we demonstrate that Rad5 plays opposite roles in lesion tolerance: i) Rad5 favors error-free lesion bypass by acPvaPng template switching through polyubiquiPnaPon of PCNA; ii) Rad5 is also required for TLS by recruiPng the TLS polymerase Rev1. We also show that the helicase acPvity does not play any role in lesion tolerance/

Evaluation of 3D-CEUS in the Recurrence of Liver Cancer after Radiofrequency Ablation

Background. Radiofrequency ablation (RFA) has the similar curative effects to surgery, but RFA will lead to higher postoperative local recurrence rate. 3D-CEUS is a minimally invasive examination method, which is used to analyze the sensitivity to postoperative recurrence in this study. Methods. The clinical data of 60 patients with liver cancer admitted to our hospital (February 2018-February 2020) were retrospectively analyzed. All patients were treated with RFA and were followed up with 3D-CEUS, MRI, and enhanced CT examination after surgery. The ROC curve was used to analyze the differences of different examination methods in judging postoperative recurrence. Results. For the 60 patients, 52 patients (86.7%) had a single lesion and 8 patients (13.3%) had multiple lesions, with a total of 72 lesions. After RFA, 56 lesions (77.8%) were completely inactivated and 16 lesions (22.2%) remained. Totally inactivated lesions were detected as follows: 51 (91.1%) by 3D-CEUS, 42 (75.0%) by MRI, and 50 (89.3%) by enhanced CT. During a 2-year follow-up, a total of 26 recurrent lesions were detected, 24 (92.3%) by 3D-CEUS, 12 (46.2%) by MRI, and 25 (96.2%) by enhanced CT, indicating that the sensitivity of 3D-CEUS and enhanced CT was obviously higher than that of MRI ( P < 0.001 ), without conspicuous difference between sensitivity of 3D-CEUS and enhanced CT ( P > 0.05 ). Conclusion. As a new imaging examination method based on artificial intelligence, 3D-CEUS has a high sensitivity in patients with liver cancer who underwent RFA, which can effectively judge the recurrence after surgery and should be widely used in practice.

The Influence of 5′,8-Cyclo-2′-deoxypurines on the Mitochondrial Repair of Clustered DNA Damage in Xrs5 Cells: The Preliminary Study

The 5′,8-cyclo-2′-deoxypurines (cdPus) affect the DNA structure. When these bulky structures are a part of clustered DNA lesions (CDL), they affect the repair of the other lesions within the cluster. Mitochondria are crucial for cell survival and have their own genome, hence, are highly interesting in the context of CDL repair. However, no studies are exploring this topic. Here, the initial stages of mitochondrial base excision repair (mtBER) were considered—the strand incision and elongation. The repair of a single lesion (apurinic site (AP site)) accompanying the cdPu within the double-stranded CDL has been investigated for the first time. The type of cdPu, its diastereomeric form, and the interlesion distance were taken into consideration. For these studies, the established experimental model of short oligonucleotides (containing AP sites located ≤7 base pairs to the cdPu in both directions) and mitochondrial extracts of the xrs5 cells were used. The obtained results have shown that the presence of cdPus influenced the processing of an AP site within the CDL. Levels of strand incision and elongation were higher for oligos containing RcdA and ScdG than for those with ScdA and RcdG. Investigated stages of mtBER were more efficient for DNA containing AP sites located on 5′-end side of cdPu than on its 3′-end side. In conclusion, the presence of cdPus in mtDNA structure may affect mtBER (processing the second mutagenic lesion within the CDL). As impaired repair processes may lead to serious biological consequences, further studies concerning the mitochondrial repair of CDL are highly demanded.

Spatial relationships of intra-lesion heterogeneity in Mycobacterium tuberculosis microenvironment, replication status, and drug efficacy

A hallmark of Mycobacterium tuberculosis (Mtb) infection with critical impact on disease development and outcome is the marked heterogeneity that exists, spanning differences in lesion types to changes in microenvironment as the infection progresses1-7. A mechanistic understanding of how this heterogeneity affects Mtb growth and treatment efficacy necessitates single bacterium-level studies in the context of intact host tissue architecture; however, such an evaluation has been technically challenging. Here, we exploit fluorescent reporter Mtb strains and the C3HeB/FeJ murine model in an integrated imaging approach to study microenvironment heterogeneity within a single lesion in situ, and analyze how these differences relate to non-uniformity in Mtb replication state, activity, and drug efficacy. We show that the pH and chloride environments differ spatially in a caseous necrotic lesion, with increased acidity and chloride levels in the lesion cuff versus the necrotic core. Conversely, a higher percentage of Mtb in the necrotic core versus the lesion cuff were in an actively replicating state, and correspondingly active in transcription and translation. Finally, examination of three first-line anti-tubercular drugs showed that efficacy of isoniazid was strikingly poor against bacteria in the lesion cuff. Our study reveals spatial relationships of intra-lesion heterogeneity, sheds light on important considerations in the development of anti-tubercular treatment strategies, and establishes a foundational framework for Mtb infection heterogeneity analysis at the single cell level in situ.

Radiomic Phenotypes of High and Low Lesion SUV Components for the Prediction of Refractory Disease in Hodgkin's Lymphoma Patients Treated with ABVD Based Therapy

Background: Hodgkin's lymphoma (HL) is a curable malignancy. However, some patients are refractory to frontline therapy. Early prediction of response to frontline therapy could identify patients who may benefit from more intensive therapy. 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) has an established role in the management of HL. Radiomic features provide a way of quantifying imaging phenotypes and have shown promising results as predictors of outcomes in different lymphomas. Furthermore, great interest has been focused on the heterogeneity of standardized uptake value (SUV) within a single lesion. Since high SUV component (HSc) and low-SUV component (LSc) regions within a single lesion may be associated with different phenotypical characteristics, the radiomic analysis for each regional SUV component may provide a more complete description of lesions. Therefore, we proposed and evaluated new descriptors to quantify the image phenotypes based on HSc and LSc of lesions in HL. Methods: A total of 61 patients with HL of all stages who were seen at MD Anderson Cancer Center between 2016 and 2020 and had analyzable pre-treatment PET/CT were selected. All patients received standard of care ABVD or AVD regimens with or without radiation (Table 1A). Pre-treatment PET/CT scans were analyzed, and HL lesions were semi-automatically segmented using MIM 7 (Cleveland, OH) based on a SUV max threshold of 2.5. Manual edits were made and reviewed by a nuclear medicine physician and a lymphoma specialist. A total of 110 radiomic features were extracted from the segmented lesions in CT and PET using the open-source package of 'PyRadiomics' (Table 1B). Detailed description and algorithms of the extracted radiomics features are available at https://pyradiomics.readthedocs.io/en/latest/features.html. Additionally, each lesion was partitioned into HSc and LSc based on a cutoff value of 3 times the liver SUV mean (Figure A). The ratio of features between SUV components (HSc, LSc) and the lesion area was calculated. Furthermore, the feature difference between HSc and LSc was obtained. The maximum, minimum, average, and standard deviation of the radiomic features within multiple lesions were computed to reveal the distribution of features. A sequential forward feature selection was applied to select the significant features for building a logistic regression model, to predict refractory disease according to Lugano criteria. Two logistic regression models were constructed for early and advanced stage patients. Quantitative measures, namely metabolic tumor volume (MTV), total lesion glycolysis (TLG), and SUV max were measured for comparison. The leave-one-out-cross-validation (LOOCV) was applied to yield the receiver-operator-characteristics curve; the area under the curve (AUC) was then computed to evaluate the performance of the proposed model compared to quantitative measurements using DeLong's test. Results: The average of small dependence high gray level emphasis (GLDM) from PET, the difference of major axis length between high- and low- SUV component from PET, and the difference of 10th Percentile (histogram) between high- and low- SUV component from PET were selected for identifying the refractory disease in early stage lesions; the maximum of correlation (GLCM) from PET, SD of small dependence emphasis (GLDM) from PET, and SD of the inverse difference moment normalized (GLCM) from PET were selected for identifying refractory disease in advanced stage lesions. Based on LOOCV, the proposed radiomics model achieved an AUC of 0.93 for refractory disease prediction, which was significantly superior to MTV (AUC, 0.66; P = 0.01), TLG (AUC, 0.64; P = 0.01), and SUV max (AUC, 0.61; P = 0.01) (Figure B) Conclusion: High and low SUV components-based radiomic model of PET/CT was potentially useful for upfront prediction of refractory HL. Validation in a larger cohort using different segmentation methods, inclusion of additional treatment subgroups, comparison to other predictors, and correlation with survival outcomes are underway. Figure 1 Figure 1. Disclosures Ahmed: Seagen: Research Funding; Merck: Research Funding; Tessa Therapeutics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Xencor: Research Funding. Steiner: BMS: Research Funding; Seattle Genetics: Research Funding; Rafael Pharmaceuticals: Research Funding. Pinnix: Merck Inc: Research Funding. Wang: Molecular Templates: Research Funding; The First Afflicted Hospital of Zhejiang University: Honoraria; Hebei Cancer Prevention Federation: Honoraria; Bayer Healthcare: Consultancy; Mumbai Hematology Group: Honoraria; Pharmacyclics: Consultancy, Research Funding; BioInvent: Research Funding; Celgene: Research Funding; Physicians Education Resources (PER): Honoraria; Miltenyi Biomedicine GmbH: Consultancy, Honoraria; Scripps: Honoraria; Janssen: Consultancy, Honoraria, Research Funding; Imedex: Honoraria; Dava Oncology: Honoraria; Epizyme: Consultancy, Honoraria; Clinical Care Options: Honoraria; BGICS: Honoraria; CAHON: Honoraria; VelosBio: Consultancy, Research Funding; Loxo Oncology: Consultancy, Research Funding; InnoCare: Consultancy, Research Funding; BeiGene: Consultancy, Honoraria, Research Funding; Anticancer Association: Honoraria; Genentech: Consultancy; AstraZeneca: Consultancy, Honoraria, Research Funding; CStone: Consultancy; Newbridge Pharmaceuticals: Honoraria; Juno: Consultancy, Research Funding; Acerta Pharma: Consultancy, Honoraria, Research Funding; Chinese Medical Association: Honoraria; Kite Pharma: Consultancy, Honoraria, Research Funding; Oncternal: Consultancy, Research Funding; DTRM Biopharma (Cayman) Limited: Consultancy; OMI: Honoraria; Moffit Cancer Center: Honoraria; Lilly: Research Funding.

The impact of multiple lesions on progression-free survival of meningiomas: a 10-year multicenter experience

OBJECTIVE Multiple meningiomas (MMs) occur in as many as 18% of patients with meningioma, and data on progression-free survival (PFS) are scarce. The objective of this study was to explore the influence of the number of lesions and clinical characteristics on PFS in patients with WHO grade I meningiomas. METHODS The authors retrospectively reviewed the records of all adults diagnosed with a meningioma at their three main sites from January 2009 to May 2020. Progression was considered the time from diagnosis until radiographic growth of the originally resected meningioma. A secondary analysis was performed to evaluate the time of diagnosis until the time to second intervention (TTSI). Univariable and multivariable analyses were conducted to assess whether the number of lesions or any associated variables (age, sex, race, radiation treatment, tumor location, and extent of resection) had a significant impact on PFS and TTSI. RESULTS Eight hundred thirty-eight patients were included. Use of a log-rank test to evaluate PFS and TTSI between a single and multiple lesions showed a significantly shorter progression for MM (p < 0.001 and p < 0.001, respectively). Multivariable Cox regression analysis showed significantly inferior PFS on MM compared to a single lesion (hazard ratio [HR] 2.262, 95% confidence interval [CI] 1.392–3.677, p = 0.001) and a significantly inferior TTSI for patients with MM when compared to patients with a single meningioma (HR 2.377, 95% CI 1.617–3.494, p = 0.001). By testing the number of meningiomas as a continuous variable, PFS was significantly inferior for each additional meningioma (HR 1.350, 95% CI 1.074–1.698, p = 0.010) and TTSI was significantly inferior as well (HR 1.428, 95% CI 1.189–1.716, p < 0.001). African American patients had an inferior PFS when compared to non-Hispanic White patients (HR 3.472, 95% CI 1.083–11.129, p = 0.036). CONCLUSIONS The PFS of meningiomas appears to be influenced by the number of lesions present. Patients with MM also appear to be more prone to undergoing a second intervention for progressive disease. Hence, a closer follow-up may be warranted in patients who present with multiple lesions. These results show a decreased PFS for each additional lesion present, as well as a shorter PFS for MM compared to a single lesion. When assessing associated risk factors, African American patients showed an inferior PFS, whereas older age and adjuvant therapy with radiation showed an improved PFS.

Comparison of Long-Term Outcomes Between 7 Days and 28 Days Albendazole Monotherapy in the Treatment of Single-Lesion Neurocysticercosis in Children

Objectives: The objective was to compare the long-term clinical, radiological, and cognitive outcomes in children with single-lesion neurocysticercosis who received 7 or 28 days of albendazole therapy. Methodology: This observational study conducted over 1 year included (1) consecutive children with single-lesion neurocysticercosis who received 7 or 28 days of albendazole therapy in the acute state and (2) completed follow-up for at least 5 years. Seizure recurrence, resolution of lesions, cognition (Malin’s Intelligence Scale for Indian Children), behavior, and school performance (National Initiative for Children Healthcare Quality Vanderbilt Assessment Scale) were assessed. Results: Group A (albendazole for 7 days) comprised 55 children, and group B (albendazole for 28 days) included 48 children. The mean age at the time of diagnosis of neurocysticercosis was 6.6 ± 1.8 years; the mean age at the time of assessment for the study was 13.2 ± 1.2 years. Focal-onset seizures were the most common clinical presentation (58.3%). The majority of lesions were ring-shaped (92.3%) or colloidal (58.2%), with perilesional edema (89.3%). In the long-term follow-up, radiological resolution of the lesions was comparable in both groups. Complete resolution was seen in 52.7% receiving 7 days and 54.2% receiving 28 days albendazole. Seizures recurred in 20% receiving 7 days and 20.8% receiving 28 days albendazole. Overall, a low intelligence quotient (IQ < 70) was seen in 55.3% cases, “somewhat problematic” school performance in 12%, and behavioral abnormalities were present in 20% of the cases. The results were comparable between the 2 groups. Conclusion: Seizure control, radiological resolution of lesion, school performance, cognitive and behavioral outcomes in the long term are comparable in children with single-lesion neurocysticercosis who have received albendazole cysticidal therapy for 7 days and 28 days. Recurrence of seizure is seen with both regimens in the long term, necessitating regular follow-up and discussion regarding the risk of recurrence before a withdrawal of anticonvulsant therapy.

577-nm high-power optically pumped semiconductor laser is safe and effective in the treatment of inflammatory acne: a prospective, single-center, split-face comparative study

Objective This study aimed to appraise the efficacy of a 577-nm high-power optically pumped semiconductor laser (HOPSL) for the treatment of inflammatory acne. Methods The study included 50 patients with acne vulgaris (inflammatory type), 14 men, and 36 women; patient ages ranged from 16 to 35 years. The left side of the face was treated with a single pass of a 577-nm high-power optically pumped semiconductor laser (HOPSL) every 2 weeks for 3 sessions. The severity of acne examined prior to the first session and 4 weeks after the last session (Investigator's Global Assessment of acne severity, IGA; single lesion count). Results At baseline, no statistically significant difference in the severity of inflammatory acne lesions between both sides was observed. One month after the final session, a significant improvement (IGA reduction of > 50%) of the overall severity of acne was observed in 49 patients (98%) on the laser-treated side versus 41 (82%) the control side of the face (P < .05). Hence, we found a significant reduction in the mean percentage of inflammatory papules, pustules, and nodules on the laser-treated versus the control side (79.33 vs 56.92, 78.04 vs 43.33, 64.85 vs 21.93%, respectively) (P < 0.05). Side effects in the form of erythema and irritation during sessions were transient and tolerated by the patients. Conclusion The 577-nm high-power optically pumped semiconductor laser is effective and safe for the treatment of inflammatory lesions (papules, pustules, and nodules) in acne patients.