Impact of Sox11 over-expression in Ba/F3 cells

A large-scale functional analysis of genes expressed differentially in insulin secreting MIN6 sublines with high versus mildly reduced glucose-responsiveness

Molecular mechanisms of glucose-stimulated insulin secretion (GSIS) from pancreatic β-cells are not fully understood. GSIS deteriorations are believed to underlie the pathogenesis of type 2 diabetes mellitus. By comparing transcript levels of 3 insulin secreting MIN6 cell sublines with strong glucose-responsiveness and 3 with mildly reduced responsiveness, we identified 630 differentially expressed genes. Using our recently developed system based on recombinase-mediated cassette exchange, we conducted large-scale generation of stable clones overexpressing such genes in the doxycycline-regulated manner. We found that overexpressions of 18, out of 83, genes altered GSIS. Sox11 ((sex determining region Y)-box 11) was selected to confirm its roles in regulating insulin secretion, and the gene was subjected to shRNA-mediated suppression. While Sox11 overexpression decreased GSIS, its suppression increased GSIS, confirming the role of Sox11 as a negative regulator of insulin secretion. Furthermore, metabolic experiments using radiolabelled glucose showed Sox11 to participate in regulating glucose metabolism. Our data suggested that overexpression screening is a feasible option for systemic functional testing to identify important genes in GSIS.

WX-0593 combined with an epithelial growth factor receptor (EGFR) monoclonal antibody in the treatment of xenograft tumors carrying triple EGFR mutations

Background

To evaluate the safety and therapeutic efficacy of WX-0593, a newly developed potent anaplastic lymphoma kinase (ALK) inhibitor, in combination with an epithelial growth factor receptor (EGFR) monoclonal antibody (QL1203 or Vectibix) for the treatment of xenograft tumors carrying mutant EGFR and osimertinib-resistant mutations (EGFR/T790M/C797S).

Methods

The inhibition of tumor cell proliferation by WX-0593 and Vectibix alone or combined was evaluated in four EGFR triple-mutant cell lines: PC9 (EGFR Del19/T790M/C797S), NCI-H1975 (EGFR L858R/T790M/C797S), Ba/F3 (EGFR L858R/T790M/C797S and EGFR Del19/T790M/C797S). The in vivo antitumor efficacy of WX-0593 alone or combined with QL1203 or Vectibix was evaluated in xenograft tumor models of BALB/c nude mice developed from H1975 (EGFR-Del19/T790M/C797S) and Ba/F3 (EGFR-L858R/T790M/C797S) cell lines. Mice were randomized into groups and treated with or without WX-0593, QL1203, Vectibix, or their combination. The tumor volume, mouse body weight, and therapeutic side effects were monitored routinely. Blood samples were obtained from all mice at different time points after the last dosage of treatment to evaluate the pharmacokinetic parameters of the drugs.

Results

WX-0593 and Vectibix showed a strong synergistic inhibitory effect on the proliferation of two EGFR triple-mutant Ba/F3 cell lines (EGFR L858R/T790M/C797S and Del19/T790M/C797S), but little synergistic inhibitory effect on the proliferation of NCI-H1975 (EGFR L858R/T790M/C797S) and PC9 (EGFR Del19/T790M/C797S). In vivo, WX-0593 (25 mg/kg) showed a modest therapeutic effect when combined with QL1203 or Vectibix, but had no effect on tumor growth as a monotherapy at this dosage. WX-0593 (75 mg/kg) exhibited modest antitumor efficacy that was further enhanced in combination with QL1203 or Vectibix in both tumor models (H1975 and Ba/F3). No significant body weight alteration, any other side effect, or deaths were observed during treatment. Pharmacokinetic analysis showed that the serum level of QL1203 or Vectibix was significantly increased and lasted longer when combined with WX-0593.

Conclusions

WX-0593 exhibited a synergetic effect with an EGFR monoclonal antibody on osimertinib-resistant EGFR-mutant non-small cell lung cancer (NSCLC) both in vitro and in vivo. Their combination showed potent antitumor efficacy and an acceptable safety profile, which may be a promising strategy for the treatment of patients with EGFR triple-mutant NSCLC resistant to osimertinib.

Clinicopathological features and prognostic value of SOX11 in childhood acute lymphoblastic leukemia

Acute lymphoblastic leukemia is marked by aberrant transcriptional features that alter cell differentiation, self-renewal, and proliferative features. We sought to identify the transcription factors exhibiting altered and subtype-specific expression patterns in B-ALL and report here that SOX11, a developmental and neuronal transcription factor, is aberrantly expressed in the ETV6-RUNX1 and TCF3-PBX1 subtypes of acute B-cell leukemias. We show that a high expression of SOX11 leads to alterations of gene expression that are typically associated with cell adhesion, migration, and differentiation. A high expression is associated with DNA hypomethylation at the SOX11 locus and a favorable outcome. The results indicate that SOX11 expression marks a group of patients with good outcomes and thereby prompts further study of its use as a biomarker.