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The ligand-induced internalization of epidermal growth factor receptor (EGFR) is generally considered to attenuate downstream signaling via its endosomal degradation. However, the endocytosis of an oncogenic EGFR variant III (EGFRvIII) is impaired, which leads to persistent signaling from the cell surface, thereby promoting the proliferation and survival of glioblastoma multiforme (GBM) cells. Cellular stress triggers the non-canonical endocytosis-recycling of EGFR by p38-mediated phosphorylation. In the present study, we used temozolomide (TMZ), the standard chemotherapeutic agent for the treatment of GBM patients, to examine whether EGFRvIII is controlled by a non-canonical mechanism. TMZ triggered the endocytic trafficking of serine phosphorylated EGFRvIII. Moreover, phosphorylation and endocytosis were abrogated by the selective p38 inhibitor SB203580, but not gefitinib, indicating that EGFRvIII is recruited to p38-mediated non-canonical endocytosis. The combination of TMZ and SB203580 also showed potential inhibitory effects on the proliferation and motility of glioblastoma cells.

Neuromyelitis optica spectrum disorder (NMOSD) is an inflammatory disease of the central nervous system (CNS) characterized by severe myelitis and optic neuritis. Double-stranded DNA (dsDNA) is involved in the pathogenesis of various autoimmune diseases, such as systemic lupus erythematosus. However, its role in NMOSD remains unclear. In this study, the concentration of dsDNA in the cerebrospinal fluid (CSF) was quantified in 23 patients with NMOSD and 16 patients with other neurological diseases (ONDs). CSF dsDNA levels in patients with NMOSD (median: 0.03 ng/µL) were significantly higher than those in patients with ONDs (median: 0.01 ng/μl). CSF dsDNA levels showed no significant difference before and after treatment. Elevation of CSF dsDNA levels may suggest its essential role in the augmentation of CNS inflammation in patients with NMOSD.

A 62-year-old woman with coronavirus disease (COVID-19) developed coma on day 19 after her pneumonia was ameliorated. Brain magnetic resonance imaging with gadolinium showed radial linear perivascular enhancement, typically seen in glial fibrillary acidic protein (GFAP) astrocytopathy, although anti-GFAP antibody results were negative. Her consciousness recovered with high-dose steroid administration. We diagnosed the patient with COVID-19-associated acute disseminated encephalomyelopathy (ADEM) with radial linear perivascular emphasis.

Epidermal growth factor receptor variant III (EGFRvIII) is the most common active EGFR mutant in glioblastoma multiforme (GBM). The expression of this mutant often correlates with a poor patient prognosis due to its ability to extend downstream signaling. The EGFR pathway is controlled by a negative feedback mechanism that restricts the extent and length of downstream signaling. To date, the role of negative feedback in the oncogenic EGFRvIII mutant remains undetermined. The present study indicated that activation of the MEK-ERK pathway led to the phosphorylation of Thr-402, a conserved negative feedback residue in the juxtamembrane domain corresponding to Thr-669 of wild-type EGFR (EGFRwt), which resulted in a rapid reduction in the tyrosine phosphorylation of EGFRvIII in U87MG human glioblastoma and 293 cells. Moreover, despite the incapability of EGFRvIII to bind ligands, EGF was indicated to downregulate the tyrosine phosphorylation of EGFRvIII by activating the EGFRwt-ERK pathway. These results demonstrated a conserved negative feedback mechanism in the activation of EGFRvIII, which presents a new aspect in functional interactions between EGFRvIII and EGFRwt in glioblastoma cells.

Intact monoclonal antibodies with a high molecular weight tend to have a poor pharmacokinetic profile and tumor penetration, and potential for eliciting host antibody responses. F(ab’) 2 fragments smaller than intact monoclonal antibodies that still maintain antigen binding could solve this problem. The objective of this study was to optimize the digestion process of nimotuzumab, an anti-EGFR monoclonal antibody, into its F(ab’) 2 fragment and investigate its potential as a therapeutic radioimmunoconjugate. Optimal conditions for digestion of nimotuzumab to its F(ab’) 2 fragment were found to be 6 hours of digestion time with a pH of 3.5 and 1:100 mol ratio of pepsin to nimotuzumab. The purity of the F(ab’) 2 -nimotuzumab was confirmed by SDS-PAGE and HPLC analysis. Prior to its labeling with lutetium-177 radionuclide, the nimotuzumab-F(ab’) 2 was conjugated to DOTA-PAMAM dendrimer [DOTA denotes 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid, PAMAM denotes poly(amidoamine)] to form conjugate of (DOTA) n -PAMAM-[nimotuzumab-F(ab’) 2 ]. Radiolabeling of DOTA-PAMAM-[nimotuzumab-F(ab’) 2 ] conjugate with 177 Lu resulted in ( 177 Lu-DOTA) n -PAMAM-[nimotuzumab-F(ab’) 2 ] with radiochemical purity > 99% after purification with a PD-10 column. Further studies still need to be performed in order to confirm the potential of this radioimmunoconjugate as a radioimmunotherapeutic agent for EGFR overexpressed cancers.

Several radiolabeled monoclonal antibodies (mAbs) have been used as radioimmunotherapy (RIT) agents for cancer therapy. The use of mAbs as RIT agents is due to their ability to carry effectors, in the form of radionuclides which emit alpha (α) particles, beta (β) particles, or auger electrons, and bind specifically to cancer expressed receptor. This paper reports the preparation of radiolabelled trastuzumab in form of ( 177 Lu-DOTA) m -PAMAM G3-F(ab') 2 -trastuzumab, which will be expected as a potential RIT agent for therapy of breast cancer overexpressed human epidermal growth factor receptor 2 (HER2). Due to its reduced molecular weight, the use of F(ab') 2 -trastuzumab on the aforementioned RIT agent candidate is expected to reach its target much faster compared to the intact trastuzumab. Meanwhile, the role of PAMAM G3 is to increase the specific activity of the radiotherapeutic agent of Lu-177 due to the ability of its 32 –NH 2 functional groups that are able to bind many DOTAs ( £ 31) which in turn can bind a large number of 177 Lu. The preparation was initiated by fragmentation of trastuzumab using pepsin enzyme in 0.02 M acetic acid buffer with a pH of 4.5 to produce F(ab') 2 -trastuzumab with a purity of 95 % after purification with PD-10 column. The F(ab') 2 -trastuzumab was then reacted with succinimidyl 4-(N-maleimidomethyl) cyclohexane-1-carboxylate (SMCC) to produce SMCC-F(ab') 2 -trastuzumab. The next reaction was to conjugate SMCC-F(ab') 2 -trastuzumab with DOTA-PAMAM G3.0-SH, which was prepared by reaction NHS-DOTA with PAMAM G3.0 and followed by reacting it with 2-iminothiolane to give (DOTA) m -PAMAM G3.0-F(ab') 2 -trastuzumab. Finally, the (DOTA) m -PAMAM G3.0-F(ab') 2 -trastuzumab was radiolabelled with 177 Lu to produce ( 177 Lu-DOTA) m -PAMAM G3.0-F(ab') 2 -trastuzumab, resulting in a radiochemical purity of 98 % after purification with PD-10 column . Received: 31 October 2015 ; Revised: 30 June 2016 ; Accepted: 25 September 2016

The use of trastuzumab as intact IgG labeling radionuclide for HER2 positive breast cancer theranostic agent is not ideal because it is slowly eliminated from the blood and normal tissues resulting in low tumor/blood (T/B) and tumor/normal tissue (T/NT) ratios. To overcome this limitation, we developed the trastuzumab F(ab′)2 fragments and radiolabeling of the fragments by β and γ-particle of Lutetium-177. F(ab)2 fragments were produced by digestion of trastuzumab IgG (Herceptin) with pepsin for 18 h at 37 °C. The F(ab′)2 fragment fractionated in PD-10 column, followed by the conjugation with 2-(4-isothiocyanatobenzyl)-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (p-SCN-Bn-DOTA) as a metal chelator and radiolabeling with 177LuCl3. Molecular weight of fragments was calculated by LCMS (Liquid Chromatography Mass Spectroscopy) and the radiochemical purity was evaluated by ITLC-SG (Instan Thin Layer Chromatography). Our study showed that the purity of F(ab′)2 fragment generated by PD-10 fractions was >98% and the molecular weight of F(ab′)2 was 98.35 kDa. The average numbers of pSCN-Bn-DOTA chelates per antibody fragment were 5.03 ± 1.5 and the optimum conjugation reactions was performed at molar ratio 20:1 (chelator to antibody). The stability test of the radioimmunoconjugate in the human serum albumin (HSA) at 37 °C showed the radiochemical purity was 91.96 ± 0.26% after 96 h storage. This indicated that the radioimmunoconjugate is relatively stable when applied to the human body's physiological condition.