Introducing enzymatic cleavage features and transfer learning realizes accurate peptide half-life prediction across species and organs.

Peptide drugs are becoming star drug agents with high efficiency and selectivity which open up new therapeutic avenues for various diseases. However, the sensitivity to hydrolase and the relatively short half-life have severely hindered their development. In this study, a new generation artificial intelligence-based system for accurate prediction of peptide half-life was proposed, which realized the half-life prediction of both natural and modified peptides and successfully bridged the evaluation possibility between two important species (human, mouse) and two organs (blood, intestine). To achieve this, enzymatic cleavage descriptors were integrated with traditional peptide descriptors to construct a better representation. Then, robust models with accurate performance were established by comparing traditional machine learning and transfer learning, systematically. Results indicated that enzymatic cleavage features could certainly enhance model performance. The deep learning model integrating transfer learning significantly improved predictive accuracy, achieving remarkable R2 values: 0.84 for natural peptides and 0.90 for modified peptides in human blood, 0.984 for natural peptides and 0.93 for modified peptides in mouse blood, and 0.94 for modified peptides in mouse intestine on the test set, respectively. These models not only successfully composed the above-mentioned system but also improved by approximately 15% in terms of correlation compared to related works. This study is expected to provide powerful solutions for peptide half-life evaluation and boost peptide drug development.

Predicting Peptide Permeability Across Diverse Barriers: A Systematic Investigation.

Peptide-based therapeutics hold immense promise for the treatment of various diseases. However, their effectiveness is often hampered by poor cell membrane permeability, hindering targeted intracellular delivery and oral drug development. This study addressed this challenge by introducing a novel graph neural network (GNN) framework and advanced machine learning algorithms to build predictive models for peptide permeability. Our models offer systematic evaluation across diverse peptides (natural, modified, linear and cyclic) and cell lines [Caco-2, Ralph Russ canine kidney (RRCK) and parallel artificial membrane permeability assay (PAMPA)]. The predictive models for linear and cyclic peptides in Caco-2 and RRCK cell lines were constructed for the first time, with an impressive coefficient of determination (R2) of 0.708, 0.484, 0.553, and 0.528 in the test set, respectively. Notably, the GNN framework behaved better in permeability prediction with larger data sets and improved the accuracy of cyclic peptide prediction in the PAMPA cell line. The R2 increased by about 0.32 compared with the reported models. Furthermore, the important molecular structural features that contribute to good permeability were interpreted; the influence of cell lines, peptide modification, and cyclization on permeability were successfully revealed. To facilitate broader use, we deployed these models on the user-friendly KNIME platform (https://github.com/ifyoungnet/PharmPapp). This work provides a rapid and reliable strategy for systematically assessing peptide permeability, aiding researchers in drug delivery optimization, peptide preselection during drug discovery, and potentially the design of targeted peptide-based materials.

A radiobiological perspective on radioresistance or/and radiosensitivity of head and neck squamous cell carcinoma.

Background: This article aimed to compile and summarize clinically relevant literature in radiation therapy, and to discuss the potential in radioresistant and radiosensitive head and neck cancer. Study Design: Narrative review. Materials and methods: Google Scholar, PubMed and the Cochrane Library were retrieved using combined key words such as "radiotherapy" and "head and neck cancer". Search strings additionally queried were "radioresistant", "radiosensitive", "head and neck region", "squamous cell carcinoma", in combination with Boolean Operators 'AND' and 'OR'. Subsequently, the resulting publications were included for review of the full text. Results: Radiotherapeutic response currently in clinical observation referred to HNSCC scoping were selected into this review. The compiled mechanisms were then detailed concerning on the clinical significance, biological characteristics, and molecular function. Conclusions: Brachytherapy or/and external-beam radiotherapy are crucial for treating HNSCC, especially the early stage patients, but in patients with locally advanced tumors, their outcome with radiation therapy is poor due to obvious radioresistance. The curative effects mainly depend on the response of radiation therapy, so an updated review is needed to optimize further applications in HNSCC radiotherapy.

Optical fiber time transmission technology based on a double-fiber round-trip method.

In this paper, an optical fiber time transmission technology based on a double-fiber round-trip method is provided. In the system, the one-way transmission delay from the master station to the slave station can be calculated directly through the measurement of three time interval counters and their ratio relationship. The method eliminates the influence of fiber length expansion and round-trip transmission delay fluctuation, which is caused by ambient temperature change. The master and slave stations are connected by 100 km and 80 km optical fibers, respectively, and the temperature of the optical fiber link varies from -20∘C to 40°C. Compared with the single-fiber round-trip method, the time interval error of a double-fiber round-trip method is reduced from 1.4 ns to 80 ps when the wavelength is 1310-1550 nm, and from 320 to 80 ps when the wavelength is 1490-1550 nm.

Novel role for TRPC4 in regulation of macroautophagy by a small molecule in vascular endothelial cells.

Macroautophagy (autophagy) is an important factor affecting the function of vascular endothelial cells (VECs) and must be tightly regulated in these cells. However, the precise mechanisms underlying this process, particularly in the presence of serum, remain obscure. In this study, we identified trans-3,5,4'-trimethoxystilbene (TMS) as a potent small molecule inducer of autophagy in human umbilical vascular endothelial cells (HUVECs) in the presence of serum. Using high-throughput DNA microarray and siRNA transfection technologies, we demonstrated that TMS induced autophagy by up-regulating the expression of the transient receptor potential canonical channel 4 (TRPC4), an important cation channel in HUVECs. In addition, the overexpression of TRPC4 by plasmid transfection also induced autophagy. Mechanistic studies revealed that the up-regulation of TRPC4 increased the intracellular Ca²âº concentration, which, in turn, activated the Ca²âº/CaMKKß/AMPK pathway, leading to mTOR inhibition and autophagy. Our study identifies a novel role for TRPC4 in the regulation of autophagy in VECs. TMS is a useful new tool for investigating the molecular mechanism of autophagy in VECs and may serve as a potential lead compound for developing a class of autophagy inducers to treat autophagy-related diseases.

SRY gene transferred by extracellular vesicles accelerates atherosclerosis by promotion of leucocyte adherence to endothelial cells.

We set out to investigate whether and how SRY (sex-determining region, Y) DNAs in plasma EVs (extracellular vesicles) is involved in the pathogenesis of atherosclerosis. PCR and gene sequencing found the SRY gene fragment in plasma EVs from male, but not female, patients; EVs from male patients with CAD (coronary artery disease) had a higher SRY GCN (gene copy number) than healthy subjects. Additional studies found that leucocytes, the major source of plasma EVs, had higher SRY GCN and mRNA and protein expression in male CAD patients than controls. After incubation with EVs from SRY-transfected HEK (human embryonic kidney)-293 cells, monocytes (THP-1) and HUVECs (human umbilical vein endothelial cells), which do not endogenously express SRY protein, were found to express newly synthesized SRY protein. This resulted in an increase in the adherence factors CD11-a in THP-1 cells and ICAM-1 (intercellular adhesion molecule 1) in HUVECs. EMSA showed that SRY protein increased the promoter activity of CD11-a in THP-1 cells and ICAM-1 in HUVECs. There was an increase in THP-1 cells adherent to HUVECs after incubation with SRY-EVs. SRY DNAs transferred from EVs have pathophysiological significance in vivo; injection of SRY EVs into ApoE-/- (apolipoprotein-knockout) mice accelerated atherosclerosis. The SRY gene in plasma EVs transferred to vascular endothelial cells may play an important role in the pathogenesis of atherosclerosis; this mechanism provides a new approach to the understanding of inheritable CAD in men.

MicroRNA-30a promotes B cell hyperactivity in patients with systemic lupus erythematosus by direct interaction with Lyn.

OBJECTIVE: To investigate why the level of Lyn is significantly decreased in B cells from a majority of patients with systemic lupus erythematosus (SLE) and to determine the role of microRNA-30a (miR-30a) in SLE B cell hyperactivity. METHODS: Luciferase reporter gene assays were performed to identify the interaction between miR-30a and the 3'-untranslated region (3'-UTR) of Lyn. Levels of miR-30a in B cells were determined by TaqMan quantitative polymerase chain reaction (qPCR), Lyn messenger RNA levels were tested with real-time qPCR, and protein levels of Lyn were determined using Western blotting. The quantity of IgG was determined by enzyme-linked immunosorbent assay. The proliferation of B cells was measured using (3) H-thymidine incorporation. RESULTS: In B cell lines, miR-30a, but not miR-30b, miR-30c, miR-30d, or miR-30e, could specifically bind the 3'-UTR of Lyn, and overexpression of miR-30a inhibited the levels of Lyn. The level of miR-30a in B cells was significantly higher in SLE patients compared to healthy donors. The level of miR-30a was negatively associated with the level of Lyn in B cells. Overexpression of miR-30a was found to promote B cell proliferation and the production of IgG antibodies. The effect of miR-30a could be abrogated by inducing overexpression of Lyn in B cells. CONCLUSION: These results reveal that elevated expression of miR-30a is responsible for the reduction in levels of Lyn in B cells from patients with SLE, suggesting that miR-30a plays an important role in B cell hyperactivity.

Malignant Melanoma of the Sphenoid Sinus: Case Report and Literature Review.

Malignant melanoma originating from the sphenoid sinus is an extremely rare but aggressive tumor of the head and neck. A 57-year-old man had a 1 month history of headache, right trigeminal paresthesias, and upper lid ptosis. Magnetic resonance imaging showed a large mass in the right sphenoid sinus and an invasion of the right cavernous sinus and clivus. The patient underwent endoscopic endonasal transsphenoidal surgery, and pathologically revealed malignant melanoma. One month after the operation, the patient was treated with radiation therapy. Unfortunately, the patient died of distant metastasis 2 years later. Due to its rarity, there is still no effective treatment strategy and no way to assess the progression of malignant melanoma.

Comparison of "framework Shuffling" and "CDR Grafting" in humanization of a PD-1 murine antibody.

Introduction: Humanization is typically adopted to reduce the immunogenicity of murine antibodies generated by hybridoma technology when used in humans. Methods: Two different strategies of antibody humanization are popularly employed, including "complementarity determining region (CDR) grafting" and "framework (FR) shuffling" to humanize a murine antibody against human programmed death-1 (PD-1), XM PD1. In CDR-grafting humanization, the CDRs of XM PD-1, were grafted into the human FR regions with high homology to the murine FR counterparts, and back mutations of key residues were performed to retain the antigen-binding affinities. While in FR-shuffling humanization, a combinatorial library of the six murine CDRs in-frame of XM PD-1 was constructed to a pool of human germline FRs for high-throughput screening for the most favorable variants. We evaluated many aspects which were important during antibody development of the molecules obtained by the two methods, including antibody purity, thermal stability, binding efficacy, predicted humanness, and immunogenicity, along with T cell epitope prediction for the humanized antibodies. Results: While the ideal molecule was not achieved through CDR grafting in this particular instance, FR-shuffling proved successful in identifying a suitable candidate. The study highlights FR-shuffling as an effective complementary approach that potentially increases the success rate of antibody humanization. It is particularly noted for its accessibility to those with a biological rather than a computational background. Discussion: The insights from this comparison are intended to assist other researchers in selecting appropriate humanization strategies for drug development, contributing to broader application and understanding in the field.

Comparison of supraorbital keyhole approach and extended transsphenoidal approach in endoscopic surgery for tuberculum sellae meningioma: A case series.

The endoscope-assisted supraorbital keyhole approach and extended transsphenoidal approach have been widely used in the treatment of tuberculum sellae meningiomas (TSMs). The purpose of the present study was to retrospectively analyze and compare the characteristics and efficacy of the two surgical approaches under the endoscope in the resection of TSMs. In the present study, 36 patients with TSMs who underwent surgical resection are presented, including one group of 17 cases with an endoscopic supraorbital keyhole approach and the other group of 19 cases with an endoscopic extended transsphenoidal approach. The clinical characteristics, diagnosis, treatment process and treatment effect of the two groups were analyzed retrospectively, and the two surgical approaches were also compared. The gross total resection rates of the two groups were similar, reaching 94.5 and 94.7%, respectively. The postoperative visual acuity recovery showed that in the endoscopic supraorbital keyhole approach group, 23 eyes were improved, 8 eyes were maintained and 3 eyes deteriorated, and the visual recovery was 67.6%. In the endoscopic extended transsphenoidal approach group, 32 eyes were improved, 4 eyes were maintained and 2 eyes deteriorated, and the visual recovery was 84.2%. In the supraorbital keyhole approach group, there was no cerebrospinal fluid leakage, while in the extended transsphenoidal approach group, cerebrospinal fluid leakage occurred in 3 cases (15.8%). In these two groups, no tumor recurrence was revealed during the follow-up of ~5 years. Both the endoscope-assisted supraorbital keyhole approach and the extended transsphenoidal approach were effective and safe. The endoscopic supraorbital keyhole approach treated TSMs with lateral extension, but it was not enough to protect the optic nerve. The endoscopic extended transsphenoidal approach protected the optic nerve, but the risk of cerebrospinal fluid leakage was increased. In conclusion, these two surgical methods have their own advantages and limitations.

Investigating the active chemical constituents and pharmacology of Nanocnide lobata in the treatment of burn and scald injuries.

OBJECTIVE: To identify the most effective fraction of Nanocnide lobata in the treatment of burn and scald injuries and determine its bioactive constituents. METHODS: Chemical identification methods were used to analyze solutions extracted from Nanocnide lobata using petroleum ether, ethyl acetate, n-butanol using a variety of color reactions. The chemical constituents of the extracts were identified by ultra-performance liquid chromatography (UPLC)-mass spectrometry (MS). A total of 60 female mice were randomly divided into the following 6 groups: the petroleum ether extract-treated group; the ethyl acetate extract-treated group; the n-butanol extract-treated group; the model group; the control group; and the positive drug group. The burn/scald model was established using Stevenson's method. At 24 hours after modeling, 0.1 g of the corresponding ointment was evenly applied to the wound in each group. Mice in the model group did not undergo treatment, while those in the control group received 0.1 g of Vaseline. Wound characteristics, including color, secretions, hardness, and swelling, were observed and recorded. Photos were taken and the wound area calculated on the 1st, 5th, 8th, 12th, 15th, 18th and 21st days. Hematoxylin-eosin (HE) staining was utilized to observe the wound tissue of mice on the 7th, 14th, and 21st days. An enzyme-linked immunosorbent assay (ELISA) kit was used to measure the expression of tumor necrosis factor (TNF)-α, interleukin (IL)-10, vascular endothelial growth factor (VEGF) and transforming growth factor (TGF)-ß1. RESULTS: The chemical constituents of Nanocnide lobata mainly include volatile oils, coumarins, and lactones. UPLC-MS analysis revealed 39 main compounds in the Nanocnide lobata extract. Among them, ferulic acid, kaempferitrin, caffeic acid, and salicylic acid have been confirmed to exhibit anti-inflammatory and antioxidant activity related to the treatment of burns and scalds. HE staining revealed a gradual decrease in the number of inflammatory cells and healing of the wounds with increasing time after Nanocnide lobata extract administration. Compared with the model group, the petroleum ether extract-treated group showed significant differences in the levels of TNF-α (161.67±4.93, 106.33±3.21, 77.67±4.04 pg/mL) and IL-10 (291.77±4.93, 185.09±9.54, 141.33±1.53 pg/mL) on the 7th, 14th, and 21st days; a significant difference in the content of TGF-ß1 (75.68±3.06 pg/mL) on the 21st day; and a significant difference in the level of VEGF (266.67±4.73, 311.33±10.50 pg/mL) on the 7th and 14th days respectively. CONCLUSION: Petroleum ether Nanocnide lobata extract and the volatile oil compounds of Nanocnide lobata might be effective drugs in the treatment of burn and scald injuries, as they exhibited a protective effect on burns and scalds by reducing the expression of TNF-α, IL-10 and TGF-ß1 and increasing the expression of VEGF. In addition, these compounds may also exert pharmacological effects that promote wound tissue repair, accelerate wound healing, and reduce scar tissue proliferation, inflammation and pain.

Pure endoscopic minimally invasive surgery with a non­expandable tubular retractor for intradural extramedullary spinal tumors.

Minimally invasive spinal surgery (MISS) for intradural extramedullary (IDEM) spinal tumors is a safe and effective surgical strategy. Currently, various tubular retractors are widely used in the MISS of IDEM spinal tumors, primarily relying on microscopic visualization. To the best of the authors' knowledge, there is no report of pure endoscopic surgery with parallel non-expandable tubular retractors for IDEM spinal lesions. The present study reports a case series of IDEM spinal tumors that were treated via pure endoscopic MISS with a parallel non-expandable tubular retractor. The extent of tumor resection was evaluated by comparing preoperative and postoperative magnetic resonance imaging (MRI). The initial and follow-up clinical conditions were assessed according to the visual analog scale for pain and the modified McCormick scale for neurological status. Postoperative MRI demonstrated that all cases had achieved a gross total resection. After the operation, the clinical symptoms of all patients were significantly improved and there were no serious postoperative complications. At the initial follow-up, the pain experienced by the patients was significantly reduced or had even disappeared, and the neurological deficit was improved by at least one grade on the modified McCormick scale. The present report indicates that pure endoscopic MISS with a parallel non-expandable tubular retractor may be an effective and safe surgical strategy for IDEM spinal tumor resection.

Endoscopic endonasal surgery for non-invasive pituitary neuroendocrinology tumors with incomplete pseudocapsule.

Background: Pituitary neuroendocrinology tumors (PitNETs) with pseudocapsule can be effectively removed by the pseudocapsule-based extracapsular resection technique. In the areas without pseudocapsule, the tumor cells can spread into the adjacent tissues at the cellular level, which brings a great challenge to achieving total tumor resection. Methods: Our surgical strategy for PitNETs with an incomplete pseudocapsule is to combine the pseudocapsule-based extracapsular resection technique with the intensive excision technique for the removal of the tumor. Specifically, the pseudocapsule-based extracapsular resection technique is applied in the areas with pseudocapsule, while in the areas without pseudocapsule, the intensive excision technique bounded by adjacent normal structures is adopted. Moreover, a pathological examination was performed to determine the situations of pseudocapsule and tumor cell remnant. Results: All growth hormone-secreting PitNETs achieved biochemical remission after surgery. There was no deterioration of pituitary functions postoperatively, and the preoperative hypopituitarism had improved in all patients postoperatively. In total, two cases suffered a transient diabetes insipidus, and intraoperative cerebrospinal fluid leakage was observed in two cases but no postoperative cerebrospinal fluid leakage in all cases. There was no recurrence during the follow-up. The fragmental pseudocapsule and small tumor remnants were found in the majority of suspicious tissues by histological staining. Conclusion: The effectiveness and safety of the surgical strategy were preliminarily explored for removing PitNETs without incomplete pseudocapsules. In overview, the pseudocapsule-based extracapsular resection technique is applied in areas with pseudocapsule, while the intensive excision bounded by adjacent normal structures is adopted in other areas.

Successful multidisciplinary therapy for a patient with liver metastasis from ascending colon adenocarcinoma: A case report and review of literature.

BACKGROUND: Liver metastasis is the most common form of distant metastasis in colorectal cancer, and the only possible curative treatment for patients with colorectal liver metastases (CRLM) is hepatectomy. However, approximately 25% of patients with CRLM have indications for liver resection at the initial diagnosis. Strategies aimed at downstaging large or multifocal tumors to enable curative resection are appealing. CASE SUMMARY: A 42-year-old man was diagnosed with ascending colon cancer and liver metastases. Due to the huge lesion size and compression of the right portal vein, the liver metastases were initially diagnosed as unresectable lesions. The patient was treated with preoperative transcatheter arterial chemoembolization (TACE) consisting of 5-fluorouracil/Leucovorin/oxaliplatin/Endostar®. After four courses, radical right-sided colectomy and ileum transverse colon anastomosis were performed. Postoperatively, the pathological analysis revealed moderately differentiated adenocarcinoma with necrosis and negative margins. Thereafter, S7/S8 partial hepatectomy was performed after two courses of neoadjuvant chemotherapy. Pathological examination of the resected specimen revealed a pathologically complete response (pCR). Intrahepatic recurrence was detected more than two months after the operation, and the patient was then treated with TACE consisting of irinotecan/Leucovorin/fluorouracil therapy plus Endostar®. Subsequently, the patient was treated with a γ-knife to enhance local control. Notably, a pCR was reached, and the patient's overall survival time was > 9 years. CONCLUSION: Multidisciplinary treatment can promote the conversion of initially unresectable colorectal liver metastasis and facilitate complete pathological remission of liver lesions.

Pterostilbene protects vascular endothelial cells against oxidized low-density lipoprotein-induced apoptosis in vitro and in vivo.

Vascular endothelial cell (VEC) apoptosis is the main event occurring during the development of atherosclerosis. Pterostilbene (PT), a natural dimethylated analog of resveratrol, has been the subject of intense research in cancer and inflammation. However, the protective effects of PT against oxidized low-density lipoprotein (oxLDL)-induced apoptosis in VECs have not been clarified. We investigated the anti-apoptotic effects of PT in vitro and in vivo in mice. PT at 0.1-5 µM possessed antioxidant properties comparable to that of trolox in a cell-free system. Exposure of human umbilical vein VECs (HUVECs) to oxLDL (200 µg/ml) induced cell shrinkage, chromatin condensation, nuclear fragmentation, and cell apoptosis, but PT protected against such injuries. In addition, PT injection strongly decreased the number of TUNEL-positive cells in the endothelium of atherosclerotic plaque from apoE(-/-) mice. OxLDL increased reactive oxygen species (ROS) levels, NF-κB activation, p53 accumulation, apoptotic protein levels and caspases-9 and -3 activities and decreased mitochondrial membrane potential (MMP) and cytochrome c release in HUVECs. These alterations were attenuated by pretreatment with PT. PT inhibited the expression of lectin-like oxLDL receptor-1 (LOX-1) expression in vitro and in vivo. Cotreatment with PT and siRNA of LOX-1 synergistically reduced oxLDL-induced apoptosis in HUVECs. Overexpression of LOX-1 attenuated the protection by PT and suppressed the effects of PT on oxLDL-induced oxidative stress. PT may protect HUVECs against oxLDL-induced apoptosis by downregulating LOX-1-mediated activation through a pathway involving oxidative stress, p53, mitochondria, cytochrome c and caspase protease. PT might be a potential natural anti-apoptotic agent for the treatment of atherosclerosis.

Case report: Fully endoscopic microvascular decompression for trigeminal neuralgia.

Microvascular decompression is safe, effective, and micro-invasive. Due to these advantages, it has become the mainstream treatment for trigeminal neuralgia, glossopharyngeal neuralgia, and hemifacial spasm. Initially, microvascular decompression was performed under a microscope, which limited the light source and visualization capabilities. With the development of endoscopic technology, the endoscope has been used in microvascular decompression, which further improved the visualization range and light source properties. The purpose of the present study was to investigate the efficacy of fully endoscopic microvascular decompression for the treatment of trigeminal neuralgia. In total, three patients with trigeminal neuralgia who underwent fully endoscopic microvascular decompression were evaluated. After surgery, the facial pain of all patients was significantly relieved. In addition, there were no obvious postoperative complications and no recurrence after 6 months of follow-up. These excellent surgical outcomes indicate that fully endoscopic microvascular decompression is an effective and safe method for the treatment of trigeminal neuralgia. Furthermore, it also shows that the endoscope presents advantages for use in microvascular decompression.

Case report: Fully endoscopic microvascular decompression for glossopharyngeal neuralgia.

With the advances in endoscopic technology, endoscopy is widely used in many neurosurgical procedures, such as microvascular decompression, which is an effective method to treat glossopharyngeal neuralgia, trigeminal neuralgia, and facial spasm. The purpose of this study was to determine the efficacy of fully endoscopic microvascular decompression in the treatment of glossopharyngeal neuralgia. We managed a patient with glossopharyngeal neuralgia in our department, whose main clinical manifestation was recurrent left ear and facial pain for 3 years. The patient underwent a fully endoscopic microvascular decompression. The pain in the left ear and face was significantly relieved postoperatively, and there was no recurrence at the 6-month follow-up evaluation. We describe a case of glossopharyngeal neuralgia that was successfully treated by fully endoscopic microvascular decompression, which showed that endoscopy has advantages in microvascular decompression, and fully endoscopic microvascular decompression is an effective method for glossopharyngeal neuralgia.

Enzyme-linked immunosorbent assays for quantification of MMAE-conjugated ADCs and total antibodies in cynomolgus monkey sera.

Antibody-drug conjugates (ADCs) are commonly heterogeneous and require extensive assessment of exposure-efficacy and exposure-safety relationships in preclinical and clinical studies. In this study, we report the generation of a monoclonal antibody against monomethyl auristatin E (MMAE) and the development, validation, and application of sensitive and high-throughput enzyme-linked immunosorbent assays (ELISA) to measure the concentrations of MMAE-conjugated ADCs and total antibodies (tAb, antibodies in ADC plus unconjugated antibodies) in cynomolgus monkey sera. These assays were successfully applied to in vitro plasma stability and pharmacokinetic (PK) studies of SMADC001, an MMAE-conjugated ADC against trophoblast cell surface antigen 2 (TROP-2). The plasma stability of SMADC001 was better than that of similar ADCs coupled with PEG4-Val-Cit, Lys (m-dPEG24)-Cit, and Val-Cit linkers. The developed ELISA methods for the calibration standards of ADC and tAb revealed a correlation between serum concentrations and the OD450 values, with R 2 at 1.000, and the dynamic range was 0.3-35.0 ng/mL and 0.2-22.0 ng/mL, respectively; the intra- and inter-assay accuracy bias% ranged from -12.2% to -5.2%, precision ranged from -12.4% to -1.4%, and the relative standard deviation (RSD) was less than 6.6% and 8.7%, respectively. The total error was less than 20.4%. The development and validation steps of these two assays met the acceptance criteria for all addressed validation parameters, which suggested that these can be applied to quantify MMAE-conjugated ADCs, as well as in PK studies. Furthermore, these assays can be easily adopted for development of other similar immunoassays.

Fast repair of DNA radicals.

This tutorial review highlights the mechanism of a novel non-enzymatic fast repair of DNA damage, which refers exclusively to repair DNA radicals including DNA-OH* adducts, DNA radical cations and anions by various endogenous, natural and synthetic compounds. The repair rate constants are as high as 10(9) M(-1) s(-1). In cells, when the enzymatic repair system was inhibited or before the enzymatic repair mechanism was initiated, DNA oxidative damage was significantly reduced by natural polyphenols. This decrease of DNA damage is assigned to the fast repair. Fast repair takes place through an electron transfer process, and docking of polyphenol into the DNA minor groove could be the essential step.