Anti-CD3 immunotoxins exhibit considerable promise for the induction of transplantation tolerance in pre-clinical large animal models. Recently an anti-human anti-CD3epsilon single-chain immunotoxin based on truncated diphtheria toxin has been described that can be expressed in CHO cells that have been mutated to diphtheria toxin resistance. After the two toxin glycosylation sites were removed, the bioactivity of the expressed immunotoxin was nearly equal to that of the chemically conjugated immunotoxin. This immunotoxin, A-dmDT390-sFv, contains diphtheria toxin to residue 390 at the N-terminus followed by VL and VH domains of antibody UCHT1 linked by a (G(4)S)(3) spacer (sFv). Surprisingly, we now report that this immunotoxin is severely compromised in its binding affinity toward CD3(+) cells as compared with the intact parental UCHT1 antibody, the UCHT1 Fab fragment or the engineered UCHT1 sFv domain alone. Binding was increased 7-fold by adding an additional identical sFv domain to the immunotoxin generating a divalent construct, A-dmDT390-bisFv (G(4)S). In vitro potency increased 10-fold over the chemically conjugated immunotoxin, UCHT1-CRM9 and the monovalent A-dmDT390-sFv. The in vivo potency of the genetically engineered immunotoxins was assayed in the transgenic heterozygote mouse, tgepsilon 600, in which the T-cells express human CD3epsilon as well as murine CD3epsilon. T-cell depletion in the spleen and lymph node observed with the divalent construct was increased 9- and 34-fold, respectively, compared with the monovalent construct. The additional sFv domain appears partially to compensate for steric hindrance of immunotoxin binding due to the large N-terminal toxin domain.

The mitotic spindle checkpoint (SAC) genes have been considered targets of anticancer therapies. Here, we sought to identify the attractive mitotic spindle checkpoint genes appropriate for human hepatocellular carcinoma (HCC) therapies. Through expression profile analysis of 137 selected mitotic spindle checkpoint genes in the publicly available microarray datasets, we showed that 13 genes were dramatically up-regulated in HCC tissues compared to normal livers and adjacent non-tumor tissues. A role of the 13 genes in proliferation was evaluated by knocking them down via small interfering RNA (siRNA) in HCC cells. As a result, several mitotic spindle checkpoint genes were required for maintaining the proliferation of HCC cells, demonstrated by cell viability assay and soft agar colony formation assay. Then we established sorafenib-resistant sublines of HCC cell lines Huh7 and HepG2. Intriguingly, increased TTK expression was significantly associated with acquired sorafenib-resistance in Huh7, HepG2 cells. More importantly, TTK was observably up-regulated in 46 (86.8%) of 53 HCC specimens. A series of in vitro and in vivo functional experiment assays showed that TTK overexpression promoted cell proliferation, anchor-dependent colony formation and resistance to sorafenib of HCC cells; TTK knockdown restrained cell growth, soft agar colony formation and resistance to sorafenib of HCC cells. Collectively, TTK plays an important role in proliferation and sorafenib resistance and could act as a potential therapeutic target for human hepatocellular carcinoma.

ADP-ribosylating immunotoxins are generally expressed in

Background Neoadjuvant immunotherapy is emerging as novel effective intervention in lung cancer, but study to unearth effective surrogates indicating its therapeutic outcomes is limited. We investigated the genetic changes between non-small cell lung cancer (NSCLC) patients with varied response to neoadjuvant immunotherapy and discovered highly potential biomarkers with indicative capability in predicting outcomes. Methods In this study, 3 adenocarcinoma and 11 squamous cell carcinoma NSCLC patients were treated by neoadjuvant immunotherapy with variated regimens followed by surgical resection. Treatment-naive FFPE or fresh tissues and blood samples were subjected to whole-exome sequencing (WES). Genetic alternations were compared between differently-responded patients. Findings were further validated in multiple public cohorts. Results DNA damage repair (DDR)-related InDel signatures and DDR-related gene mutations were enriched in better-responded patients, i.e., major pathological response (MPR) group. Besides, MPR patients exhibited provoked genome instability and unique homologous recombination deficiency (HRD) events. By further inspecting alternation status of homology-dependent recombination (HR) pathway genes, the clonal alternations were exclusively enriched in MPR group. Additionally, associations between HR gene alternations, percentage of viable tumor cells and HRD event were identified, which orchestrated tumor mutational burden (TMB), mutational intratumor heterogeneity (ITH), somatic copy number alteration (SCNA) ITH and clonal neoantigen load in patients. Validations in public cohorts further supported the generality of our findings. Conclusions We reported for the first time the association between HRD event and enhanced neoadjuvant immunotherapy response in lung cancer. The power of HRD event in patient therapeutic stratification persisted in multifaceted public cohorts. We propose that HR pathway gene status could serve as novel and additional indicators guiding immune-neoadjuvant and immunotherapy treatment decisions for NSCLC patients.