Inhibition of DNA replication fork progression and mutagenic potential of 1, N6-ethenoadenine and 8-oxoguanine in human cell extracts

Comparative mutagenesis of 1,N6-ethenoadenine (εA) and 8-oxoguanine (8-oxoG), two endogenous DNA lesions that are also formed by exogenous DNA damaging agents, have been evaluated in HeLa and xeroderma pigmentosum variant (XPV) cell extracts. Two-dimensional gel electrophoresis of the duplex M13mp2SV vector containing these lesions established that there was significant inhibition of replication fork movement past εA, whereas 8-oxoG caused only minor stalling of fork progression. In extracts of HeLa cells, εA was weakly mutagenic inducing all three base substitutions in approximately equal frequency, whereas 8-oxoG was 10-fold more mutagenic inducing primarily G→T transversions. These data suggest that 8-oxoG is a miscoding lesion that presents a minimal, if any, block to DNA replication in human cells. We hypothesized that bypass of εA proceeded principally by an error-free mechanism in which the undamaged strand was used as a template, since this lesion strongly blocked fork progression. To examine this, we determined the sequence of replication products derived from templates in which a G was placed across from the εA. Consistent with our hypothesis, 93% of the progeny were derived from replication of the undamaged strand. When translesion synthesis occurred, εA→T mutations increased 3-fold in products derived from the mismatched εA: G construct compared with those derived from the εA: T construct. More efficient repair of εA in the εA: T construct may have been responsible for lower mutation frequency. Primer extension studies with purified pol η have shown that this polymerase is highly error-prone when bypassing εA. To examine if pol η is the primary mutagenic translesion polymerase in human cells, we determined the lesion bypass characteristics of extracts derived from XPV cells, which lack this polymerase. The εA: T construct induced εA→G and εA→C mutant frequencies that were approximately the same as those observed using the HeLa extracts. However, εA→T events were increased 5-fold relative to HeLa extracts. These data support a model in which pol η-mediated translesion synthesis past this adduct is error-free in the context of semiconservative replication in the presence of fidelity factors such as PCNA

Role of the ribosome in protein folding

In all organisms, the ribosome synthesizes and folds full length polypeptide chains into active three-dimensional conformations. The nascent protein goes through two major interactions, first with the ribosome which synthesizes the polypeptide chain and holds it for a considerable length of time, and then with the chaperones. Some of the chaperones are found in solution as well as associated to the ribosome. A number of in vitro and in vivo experiments revealed that the nascent protein folds through specific interactions of some amino acids with the nucleotides in the peptidyl transferase center (PTC) in the large ribosomal subunit. The mechanism of this folding differs from self-folding. In this article, we highlight the folding of nascent proteins on the ribosome and the influence of chaperones etc. on protein folding

Factors affecting health-related quality of life among patients with colorectal cancer using the european organization for research and treatment of cancer quality of life core questionnaire-CR29

Introduction: The deterioration of health caused by colorectal Cancer (CRC) and its treatment leads to physiological, functional, and social damage impairing a CRC patient's health-related quality of life (HRQoL). The study was done to estimate the factors affecting the HR QoL among patients with CRC. Methodology: Fifty-four CRC patients who had completed the treatment with surgery/chemotherapy/radiotherapy in a peripheral Medical College between May 2021 and April 2022 were enrolled. The objective was to assess patient's perceived global health status and QoL (GHS/QoL), functional outcomes, and symptoms measured by the European organization for research and treatment of cancer Quality of life questionnaire core (QLQ-C30) and the CRC-specific QLQ-CR29 and to determine the demographics, clinical, treatment factors and symptom scales of the QLQ-C30/QLQ-CR29 that are associated with of GHS/QoL in patients with CRC Results: The mean age was 46 years, 59% were male, 41% had other long-term medical conditions, an ostomy was present in 30% and 41% of respondents had multimodal CRC treatment with surgery, radiotherapy, and chemotherapy. The final analysis of stepwise multiple regression revealed that four variables namely physical functioning, sexual interest, body image, and fatigue remained significant independent predictors of overall HRQoL score in CRC survivors accounting for 67.4% of the variation in overall HRQoL. Physical functioning made the strongest contribution. Women, at the extremes of the age groups (≥60 years), with an ostomy, without a spouse/partner, and those with other medical conditions in addition reported poorer functioning, symptoms, or overall HRQoL. Conclusions: The current study identifies factors associated with overall HRQoL among CRC survivors. Functional capacity and CRC-related problems were most strongly associated with overall HRQoL among CRC survivors. Greater efforts to identify CRC-related symptoms and diminished physical functional capacity among CRC survivors are warranted in an attempt to improve their overall HRQoL

A pilot study on feasibility, toxicity and efficacy of novel hypofractionated radiation therapy in advanced nonnasopharyngeal head and neck carcinoma treated with palliative intent

Introduction: For palliative treatment in patients with advanced inoperable stage IV head and neck cancerhypofractionated radiotherapy is an efficient, cost-effective option, providing a logistic advantage.Though there are multiple regimens prescribed, no standard of care has been confirmed. In this study,a novel hypofractionated regimen has been tested for feasibility and toxicity along with an assessment ofobjective treatment response and survival along with self-reported quality of life. Patients and methods: 30 Patients, having pathologically proven advanced and metastatic non-nasopharyngealsquamous cell carcinoma of Head and Neck (Stage IV) attending the Radiotherapy Departmentof Hospital were allocated to the prescribed hypofractionation regime with 35 Gray in 7 fractions, givenas 2 days a week (total 3.5 weeks). In patients with good response and tolerability, 10 Gray boosts in2 fractions were given. Patients were followed up at regular intervals for at least 1 year. Results: The regimen faced a 97% treatment completion rate. Mean time to completion (from first contact)is 5.8 (95% CI = 5.7–6.0) weeks. The toxicity of this treatment regimen was tolerable with 23.3%acute and 33.3% incidence of chronic grade 3/4 toxicities. Objective response rate of this study was 66.7%(p = 0.001) with further 16.7% patients having stable disease. After one month of treatment significantimprovement of quality of life was reported in terms of global health score, functional score and symptomsscore. Mean progression-free survival is 34.4 (95% CI = 27.8–41.1) weeks with 49.4 (95% CI = 44.3–54.5)weeks of overall survival in 1 year follow up period. Conclusions: The regimen is well tolerated and is highly feasible and has provided a good response rateand improved quality of life immediately after treatment along with a better one-year overall survival rate

A facile strategy for the preparation of polypropylene sulfide nanoparticles for hydrophobic and base‐sensitive cargo

Polypropylene sulfide (PPS) as reactive oxygen species (ROS) responsive nanoparticles (NPs) have attained great interest for drug delivery applications in many diseases such as cancer, pulmonary, neurovascular, cardiovascular, and age-related diseases. Despite great potential of PPS NPs as a nanocarrier, it remains relatively less explored for small molecules (drug) delivery, as the current method of PPS NPs synthesis involving strong bases like sodium methoxide (NaOMe) and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) results in breakdown of base sensitive drugs or molecules. Herein, we are reporting a facile synthesis method for PPS NPs preparation with high drug loading capacity (five times higher than the reported synthesis method) of base-sensitive cargos (Paclitaxel/Dil dye) within the PPS matrix and protection from possible breakdown of drug during synthesis. The NPs prepared via our method possess oxidative-responsive release of drug, preservation of drug bioactivity, and excellent storage stability at room temperature or 4°C. PPS NPs system demonstrate biocompatibility and drug-loaded NPs provide efficient anticancer activity against breast cancer cells. Our method of PPS NPs synthesis is suitable to prepare a delivery system with higher loading capacity of drug and small molecules for different biomedical applications. © 2021 Wiley Periodicals LLC

Biomimicking nanofibrous gelatin microspheres recreating the stem cell niche for their ex-vivo expansion and in-vivo like differentiation for injectable stem cell transplantation

Stem cells based novel treatment modality for degenerative and immune dysfunction diseases created a huge demand of suitable carriers to support ex-vivo production of quality stem cells, and effective in-vivo transplantation of stem cells and their fate. In spite of promising candidature of nanofibrous microspheres (NFM) to recreate native stem cell niches to be used for possible scaling-up for ex-vivo stem cells expansion, it remains fairly unexplored. A systematic study on the stem cell-NFM interaction comparative with commercial microspheres (CM) has been performed for the first time. Gelatin NFM with variable physicochemical properties such as size, surface properties, surface chemistry, and variable degradability were prepared using microemulsion coupled with thermally induced phase separation (TIPS) method. Effect of physicochemical properties of NFM and their cellular interaction such as binding, morphology, metabolic activity and proliferation studies were performed using human bone marrow-derived mesenchymal stem cells (hBMSCs), human dental follicle stem cells (hDFSCs) and human gingival fibroblast (HGF) cells and compared with the commercial and solid microspheres. Gelatin NFM supports excellent cell binding, proliferation, metabolic activities and chemical cues specific differentiation. All out-turns indicate that NFM stand to be an outstanding candidate for ex-vivo cells' expansion and injectable carriers for stem cell transplantation. © 2022 Elsevier B.V

Laponite–Gelatin Nanofibrous Microsphere Promoting Human Dental Follicle Stem Cells Attachment and Osteogenic Differentiation for Noninvasive Stem Cell Transplantation

Nanofibrous microspheres (NFM) are emerging as prominent next-generation biomimetic injectable scaffold system for stem cell delivery and different tissue regeneration where nanofibrous topography facilitates ECM-like stem cells niches. Addition of osteogenic bioactive nanosilicate platelets within NFM can provide osteoconductive cues to facilitate matrix mediated osteogenic differentiation of stem cells and enhance the efficiency of bone tissue regeneration. In this study, gelatin nanofibrous microspheres are prepared containing fluoride-doped laponite XL21 (LP) using the emulsion mediated thermal induce phase separation (TIPS) technique. Systematic studies are performed to understand the effect of physicochemical properties of biomimicking NFM alone and with different concentrations of LP on human dental follicle stem cells (hDFSCs), their cellular attachment, proliferation, and osteogenic differentiation. The study highlights the effect of LP nanosilicate with biomimicking nanofibrous injectable scaffold system aiding in enhancing stem cell differentiation under normal physiological conditions compared to NFM without LP. The laponite–NFM shows suitability as excellent injectable biomaterials system for stem cell attachment, proliferation and osteogenic differentiation for stem cell transplantation and bone tissue regeneration. © 2022 Wiley-VCH GmbH

Low temperature, easy scaling up method for development of smart nanostructure hybrid lipid capsules for drug delivery application

Lipid Nanocapsules (LNCs) have been used for drug delivery in cells and animal models for several years. LNCs with unique physicochemical properties for favorable biorecognition, biocompatibility and stimuli responsive (pH/temperature etc.) properties i.e., smart-LNCs, are most promising for future nanomedicine applications. However, conventional phase inversion temperature (PIT) method of LNCs preparation may not be suitable for the fabrication of thermally labile drug loaded LNCs and smart-LNCs. Herein, we report for the first time, a novel low temperature (LT) method for the preparation of LNCs (including smart-LNCs of size 25–150 nm), hereafter, named as nanostructure hybrid lipid capsules (nHLCs), comprising safe excipients such as oil (Labrafac™ PG), surfactant (Kolliphor® HS 15, Brij® S100), and lipid (Lipoid S-75, Lipoid S PC-3, Lipoid PE 18:1/18:1, Lipoid PC 16:0/16:0 etc.). Effects of process parameters on the physicochemical properties of nHLCs were probed to optimize the process. Ternary phase diagram shows that our method allows for great flexibility in the formation of nHLCs with tailored size and composition. This method resulted in drug loaded (regorafenib used as model drug) nHLCs with 95 % encapsulation efficiency and sustained release profile at 37 °C. The drug loaded nHLCs (as prepared or in lyophilized form) has excellent storage stability at 4 °C (for more than one month) as well as biocompatibility similar to that of LNCs prepared by PIT method. Our novel LT method of LNCs (i.e. nHLCs) preparation is a generic method for the development of drug loaded (including thermally labile) and smart-LNCs for future nanomedicine applications