Creating an optimal microenvironment that mimics the extracellular matrix (ECM) of natural pulp and securing an adequate blood supply for the survival of cell transplants are major hurdles that need to be overcome in dental pulp regeneration. However, many currently available scaffolds fail to mimic essential functions of natural ECM. The present study investigated a novel approach involving the use of scaffold-free microtissue spheroids of dental pulp stem cells (DPSCs) prevascularized by human umbilical vein endothelial cells (HUVECs) in pulp regeneration. In vitro-fabricated microtissue spheroids were inserted into the canal space of tooth-root slices and were implanted subcutaneously into immunodeficient mice. Histological examination revealed that, after four-week implantation, tooth-root slices containing microtissue spheroids resulted in well-vascularized and cellular pulp-like tissues, compared with empty tooth-root slices, which were filled with only subcutaneous fat tissue. Immunohistochemical staining indicated that the tissue found in the tooth-root slices was of human origin, as characterized by the expression of human mitochondria, and contained odontoblast-like cells organized along the dentin, as assessed by immunostaining for nestin and dentin sialoprotein (DSP). Vascular structures formed by HUVECs in vitro were successfully anastomosed with the host vasculature upon transplantation in vivo, as shown by immunostaining for human CD31. Collectively, these findings demonstrate that prevascularized, scaffold-free, microtissue spheroids can successfully regenerate vascular dental pulp-like tissue and also highlight the significance of the microtissue microenvironment as an optimal environment for successful pulp-regeneration strategies.

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The purpose of this study was to establish and characterize patient-derived esophageal squamous cell carcinoma xenograft (PDECX) mice for utilization in antitumor drug discovery. A total of 96 esophageal squamous cell carcinoma (ESCC) tissues from Chinese patients were transplanted subcutaneously into immunodeficient mice. Histology, EGFR, K-ras, B-raf, and PIK3CA mutations, and HER2 gene amplifications were analyzed in both patient tumors and mouse xenograft tissues using immunohistochemistry, mutant-enriched liquid chip sequencing and fluorescence in situ hybridization assays, respectively. Furthermore, in vivo efficacy studies using five PDECX mice harboring a variety of genetic aberrations were performed using the chemotherapy agents 5-fluorouracil (5-FU) and cisplatin. Thirty-seven PDECX mouse models were successfully established in immunodeficient mice. Pathological analysis revealed similar histological architecture and degrees of differentiation between patient ESCC and xenografted tumors. No mutations were identified in EGFR, K-ras, and B-raf genes in either xenograft models or patient ESCC tissues. In contrast, PIK3CA gene mutations were detected in 12.5% (12/96) ESCC patients and 18.9% (7/37) PDECX models. Interestingly, patient ESCC tissues exhibiting HER2 overexpression or gene amplification were unable to survive in immunodeficient mice. Further analysis showed that PDECX models carrying HER2 2 þ expression had no response to 5-FU/cisplatin, compared with HER2-negative models. In conclusion, a panel of PDECX mouse models, which include PIK3CA mutant and HER2-positive models, was established and characterized thus mimicking the current clinical genetic setting of esophageal carcinoma. The sensitivity of HER2-negative ESCC models to chemotherapy supports stratification approaches in the treatment of esophageal carcinoma patients and warrants further investigation of the impact of PI3KCA on treatment response.Laboratory Investigation (2014) 94, 917-926;

These results suggest that KS-Fs or kurarinone may be developed as a novel antitumor agent.

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Osimertinib (AZD9291) is a third generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor that has demonstrated significant clinical benefits in patients with EGFR-sensitizing mutations or the T790M mutation. However, the potential therapeutic effect of osimertinib combined with ionizing irradiation (IR) is not well understood. The present study investigated treatment with osimertinib combined with IR in EGFR T790M non-small cell lung cancer (NCI-H1975) in vitro and in vivo. The results revealed that osimertinib inhibited proliferation and clonogenic survival following irradiation, decreased G2/M phase arrest in irradiated cells, and delayed DNA damage repair in a concentration- and time-dependent manner. Furthermore, osimertinib alone or in combination with IR, blocked the phosphorylation of EGFR (Tyr1068/Tyr1173), protein kinase B and extracellular signal-regulated kinase. Osimertinib also enhanced the antitumor activity of IR in tumor-bearing nude mice. The results of the present study indicated that osimertinib has therapeutic potential as a radiation-sensitizer in lung cancer cells harboring the EGFR T790M mutation, providing a rationale for clinically combining osimertinib with irradiation in EGFR T790M non-small cell lung cancer.

Background: Several EGFR TKIs have been approved for the treatment of non-small cell lung cancer (NSCLC) with L858R mutation, Exon 19 deletion, and T790M mutations. However, for patients with uncommon mutations, such as EGFR or HER2 Exon20ins, there lacks safe and effective therapy. All Exon20ins inhibitors under clinical development have a negative selectivity profile, inhibiting wild type EGFR more potently than mutant ones. Consequently, severe wild type EGFR-driven toxicities have been observed in patients. DZD9008 is an oral, potent, irreversible, wild type-selective EGFR TKI against EGFR or HER2 Exon20ins and other mutations. The present study shows anti-tumor activity of DZD9008 in tumor cell lines and xenograft models. Materials and Methods: The enzyme assay was performed by incubating DZD9008 with recombinant enzymes at 2 mM ATP concentrations. The cellular activity of DZD9008, including phosphorylation of EGFR or HER2 and cell proliferation, was evaluated in a panel of cell lines expressing wild type EGFR, mutant EGFR or HER2, using MSD assay and CellTiter-Glo assays. DZD9008 in vivo anti-tumor activity was evaluated in both cell line-derived (CDX) and patient-derived xenograft (PDX) models, carrying EGFR single or double mutations, Exon20ins mutations, and wild type EGFR. Results: The enzymatic IC50 of DZD9008 in mutant EGFR ranges from 0.4 to 2.1 nM. DZD9008 downregulated pEGFR with IC50 ranging from 1 to 22 nM in a panel of tumor cell lines expressing EGFR L858R, Exon19del, L858R/T790M, various Exon20ins or uncommon mutations. Similar activity against pHER2 was observed in tumor cells with HER2 Exon20ins mutation, with IC50 at 7 nM. In contrast, DZD9008 was less potent in modulating pEGFR in tumor cells expressing wild type EGFR, with IC50 greater than 80 nM. In cell proliferation assays, DZD9008 suppressed cell proliferation with GI50 of 1 to 60 nM in tumor cells carrying EGFR L858R, Exon19del, L858R/T790M, various Exon20ins or uncommon mutations. In CDX and PDX models carrying EGFR Exon19del single mutation, L858R/T790M double mutations, and PDX models harboring G719S/L861Q or Exon20ins, DZD9008 induced dose dependent tumor growth inhibition and regression. Good PK/PD relationship was established across these tumor models. Conclusion: DZD9008 is a potential EGFR TKI for NSCLC patients with EGFR or HER2 Exon20ins and other activating mutations. Citation Format: Yan Xu, Lin Zhang, Lifang Zhu, Yingchun Wang, Mei Wang, Zhenfan Yang. DZD9008, an oral, wild type selective EGFR inhibitor for the treatment of non-small-cell lung cancer with Exon20 insertion and other activating mutations [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3081.