development-maintenance-preclinical-patient-derived-tumor-xenograft

Development and Maintenance of a Preclinical Patient Derived Tumor Xenograft Model for the Investigation of Novel Anti-Cancer Therapies

Patient derived tumor xenograft (PDTX) models provide a necessary platform in facilitating anti-cancer drug development prior to human trials. Human tumor ...

University of Colorado Denver Anschutz Medical Campus

Antiangiogenic therapy is commonly used for the treatment of colorectal cancer (CRC). Although patients derive some clinical benefit, treatment resistance inevitably occurs. The MET signaling pathway has been proposed to be a major contributor of resistance to antiangiogenic therapy. MET is upregulated in response to vascular endothelial growth factor pathway inhibition and plays an essential role in tumorigenesis and progression of tumors. In this study, we set out to determine the efficacy of cabozantinib in a preclinical CRC patient-derived tumor xenograft model. We demonstrate potent inhibitory effects on tumor growth in 80% of tumors treated. The greatest antitumor effects were observed in tumors that possess a mutation in the PIK3CA gene. The underlying antitumor mechanisms of cabozantinib consisted of inhibition of angiogenesis and Akt activation and significantly decreased expression of genes involved in the PI3K pathway. These findings support further evaluation of cabozantinib in patients with CRC. PIK3CA mutation as a predictive biomarker of sensitivity is intriguing and warrants further elucidation. A clinical trial of cabozantinib in refractory metastatic CRC is being activated.

Potent antitumor activity of cabozantinib, a c-MET and VEGFR2 inhibitor, in a colorectal cancer patient-derived tumor explant model.

The activation of the MAPK and PI3K/AKT/mTOR pathways is implicated in the majority of cancers. Activating mutations in both of these pathways has been described in colorectal cancer (CRC), thus indicating their potential as therapeutic targets. This study evaluated the combination of a PI3K/mTOR inhibitor (PF-04691502/PF-502) in combination with a MEK inhibitor (PD-0325901/PD-901) in CRC cell lines and patient-derived CRC tumor xenograft models (PDTX).

Dual pharmacological targeting of the MAP kinase and PI3K/mTOR pathway in preclinical models of colorectal cancer.

Aurora A kinase and MEK inhibitors induce different, and potentially complementary, effects on the cell cycle of malignant cells, suggesting a rational basis for utilizing these agents in combination. In this work, the combination of an Aurora A kinase and MEK inhibitor was evaluated in pre-clinical colorectal cancer models, with a focus on identifying a subpopulation in which it might be most effective. Increased synergistic activity of the drug combination was identified in colorectal cancer cell lines with concomitant KRAS and PIK3CA mutations. Anti-proliferative effects were observed upon treatment of these double-mutant cell lines with the drug combination, and tumor growth inhibition was observed in double-mutant human tumor xenografts, though effects were variable within this subset. Additional evaluation suggests that degree of G2/M delay and p53 mutation status affect apoptotic activity induced by combination therapy with an Aurora A kinase and MEK inhibitor in KRAS and PIK3CA mutant colorectal cancer. Overall, in vitro and in vivo testing was unable to identify a subset of colorectal cancer that was consistently responsive to the combination of a MEK and Aurora A kinase inhibitor.

Combined inhibition of MEK and Aurora A kinase in KRAS/PIK3CA double-mutant colorectal cancer models.

Dysregulation of the Notch1 receptor has been shown to facilitate the development and progression of colorectal cancer (CRC) and has been identified as an independent predictor of disease progression and worse survival. Although mutations in the NOTCH1 receptor have not been described in CRC, we have previously discovered a NOTCH1 gene copy number gain in a portion of CRC tumor samples. Here, we demonstrated that a NOTCH1 gene copy number gain is significantly associated with worse survival and a high percentage of gene duplication in a cohort of patients with advanced CRC. In our CRC patient-derived tumor xenograft (PDTX) model, tumors harboring a NOTCH1 gain exhibited significant elevation of the Notch1 receptor, JAG1 ligand and cleaved Notch1 activity. In addition, a significant association was identified between a gain in NOTCH1 gene copy number and sensitivity to a Notch1-targeting antibody. These findings suggest that patients with metastatic CRC that harbor a gain in NOTCH1 gene copy number have worse survival and that targeting this patient population with a Notch1 antibody may yield improved outcomes.

A NOTCH1 gene copy number gain is a prognostic indicator of worse survival and a predictive biomarker to a Notch1 targeting antibody in colorectal cancer.

CRC is a significant cause of cancer mortality, and new therapies are needed for patients with advanced disease. TAK-733 is a highly potent and selective investigational novel MEK allosteric site inhibitor.

Antitumor activity of a potent MEK inhibitor, TAK-733, against colorectal cancer cell lines and patient derived xenografts.

The aim of the current study was to examine expression and the role, if any, of aldehyde dehydrogenase (ALDH)1B1 in pancreatic adenocarcinoma.

Aldehyde Dehydrogenase 1B1 as a Modulator of Pancreatic Adenocarcinoma.

Dysregulation of the canonical Wnt signaling pathway has been implicated in colorectal cancer (CRC) development as well as incipient stages of malignant transformation. In this study, we investigated the antitumor effects of AZ1366 (a novel tankyrase inhibitor) as a single agent and in combination with irinotecan in our patient derived CRC explant xenograft models.

The novel tankyrase inhibitor (AZ1366) enhances irinotecan activity in tumors that exhibit elevated tankyrase and irinotecan resistance.

The Aurora kinases are a family of serine/threonine kinases comprised of Aurora A, B, and C which execute critical steps in mitotic and meiotic progression. Alisertib (MLN8237) is an investigational Aurora A selective inhibitor that has demonstrated activity against a wide variety of tumor types in vitro and in vivo, including CRC.

Stacey Bagby

Medicine

University of Colorado Denver Anschutz Medical Campus

Development and Maintenance of a Preclinical Patient Derived Tumor Xenograft Model for the Investigation of Novel Anti-Cancer Therapies