Correction to: RGD4C peptide mediates anti-p21Ras scFv entry into tumor cells and produces an inhibitory effect on the human colon cancer cell line SW480 (BMC Cancer, (2021), 21, 1, (321), 10.1186/s12885-021-08056-4)
An amendment to this paper has been published and can be accessed via the original article.
RGD4C peptide mediates anti-p21Ras scFv entry into tumor cells and produces an inhibitory effect on the human colon cancer cell line SW480
Background: We prepared an anti-p21Ras scFv which could specifically bind with mutant and wild-type p21Ras. However, it cannot penetrate the cell membrane, which prevents it from binding to p21Ras in the cytoplasm. Here, the RGD4C peptide was used to mediate the scFv penetration into tumor cells and produce antitumor effects.
Method(s): RGD4C-EGFP and RGD4C-p21Ras-scFv recombinant expression plasmids were constructed to express fusion proteins in E. coli, then the fusion proteins were purified with HisPur Ni-NTA. RGD4C-EGFP was used as reporter to test the factors affecting RGD4C penetration into tumor cell. The immunoreactivity of RGD4C-p21Ras-scFv toward p21Ras was identified by ELISA and western blotting. The ability of RGD4C-p21Ras-scFv to penetrate SW480 cells and colocalization with Ras protein was detected by immunocytochemistry and immunofluorescence. The antitumor activity of the RGD4C-p21Ras-scFv was assessed with the MTT, TUNEL, colony formation and cell migration assays. Chloroquine (CQ) was used an endosomal escape enhancing agent to enhance endosomal escape of RGD4C-scFv.
Result(s): RGD4C-p21Ras-scFv fusion protein were successfully expressed and purified. We found that the RGD4C fusion protein could penetrate into tumor cells, but the tumor cell entry of was time and concentration dependent. Endocytosis inhibitors and a low temperature inhibited RGD4C fusion protein endocytosis into cells. The change of the cell membrane potential did not affect penetrability. RGD4C-p21Ras-scFv could penetrate SW480 cells, effectively inhibit the growth, proliferation and migration of SW480 cells and promote this cells apoptosis. In addition, chloroquine (CQ) could increase endosomal escape and improve antitumor activity of RGD4C-scFv in SW480 cells.
Conclusion(s): The RGD4C peptide can mediate anti-p21Ras scFv entry into SW480 cells and produce an inhibitory effect, which indicates that RGD4C-p21Ras-scFv may be a potential therapeutic antibody for the treatment of ras-driven cancers.
Response to Comments on "urinary Metabolites of Neonicotinoid Insecticides: Levels and Recommendations for Future Biomonitoring Studies in China" [Letter]
[Intraobserver reproducibility of Ki-67 assessment of breast cancers based on digital slide]
Objective: To investigate the intra-observer reproducibility of Ki-67ã€€ã€€ã€€assessment in breast cancers using three methods based on digital slide. Methods: Thirty cases of invasive breast cancer tissues were immunostained for Ki-67 by automatic stainer, and then scanned into digital pathological slides. Ki-67 positive index was measured individually by three pathologists using size-set visual assessment of hot spot (SSVAHS), size-set semi-automatic counting of hot spot(SSSACHS), and size-set automatic counting of hot spot (SSACHS), respectively, and repeated for 10 times. Intraclass correlation coefficient (ICC) of each assessment method was calculated, and the intraobserver reliability was classified as excellent, good, fair and poor according to ICC. Results: The ICC by 3 pathologists using SSVAHS was 0.832, 0.843 and 0.826, respectively, The ICC using SSSACHS was 0.926,0.938,0.929, and the ICC using SSACHS was 0.964, 0.971 and 0.968.The intraobserver reliability level of all three methods was excellent. Conclusion: The three methods of Ki-67 assessment achieve satisfactory intraobserver reproducibility, and the order of reproducibility from high to low is SSACHS, SSSACHS, and SSVAHS.
Provocation of nonepileptic seizures by suggestion in a general seizure population
Nonepileptic seizures (NES) are common and are often diagnosed at epilepsy centers by video-EEG recording of both spontaneous and suggestion-induced episodes, but no study has evaluated provocative testing in a general seizure population. We studied consecutive patients with a tentative diagnosis of epilepsy using saline provocation during video-EEG recording, suggesting that this could produce a typical seizure. Of 52 patients, 40% had no response, 23% had responses unlike their seizures, and 37% had typical episodes (positive test). Patients whose usual episodes resembled complex partial seizures (CPS) were more likely to have NES than were patients with a history of generalized tonic-clonic seizures (GTC). Of patients with positive provocations, the primary physician predicted NES in 68% of cases. This preliminary study suggests that NES are frequent in a general neurology setting, and that saline provocation is a sensitive method of identifying NES
Lower motor neuron dysfunction associated with human immunodeficiency virus infection [Case Report]
OBJECTIVE: The association of human immunodeficiency virus with a clinical picture of motor neuron disease is uncommon, with three cases reported to date. This case represents an additional case of a human immunodeficiency virus-infected patient with apparent motor neuron disease. DESIGN: Single patient case report. SETTING: Large urban public hospital. PATIENT: A 45-year-old human immunodeficiency virus-positive Hispanic man who presented with muscle wasting, fasciculations, areflexia, cranial nerve deficits, and weakness progressing to a complete quadriplegia. RESULTS: Electrophysiologic data showed evidence of diffuse denervation with normal sensory and motor nerve conductions and no evidence of demyelination. Electromyography showed diffuse sharp waves and fibrillation. CONCLUSIONS: This case demonstrates a progressive motor neuron dysfunction in a patient positive for the human immunodeficiency virus and provides additional evidence that infection with the human immunodeficiency virus should be considered in the differential diagnosis of apparent motor neuron disease