To explore the potential of navitoclax in combination with taxane-based chemotherapy in the treatment of non-small cell lung cancer (NSCLC) by defining mechanism of synergy and identifying ...correlative biomarkers.
We treated a panel of NSCLC lines with a dose matrix of paclitaxel and navitoclax (formerly ABT-263), an inhibitor of Bcl-2, Bcl-x(L), and Bcl-w (1), and evaluated synergy. We next used time-lapse microscopy to explore mechanism of synergy. Finally, we developed an immunohistochemical assay and assessed prevalence of Bcl-x(L) in NSCLC tumor tissues.
All cell lines exhibit greater than additive response to the combination of navitoclax and a taxane. These results were extended to mouse xenograft tumor models, in which the combination is more efficacious than either single-agent docetaxel or navitoclax. Addition of navitoclax to paclitaxel decreases the time from mitotic entry to cell death and changes cell fate from mitotic slippage to death during mitotic arrest. The relative levels of Bcl-x(L) and Mcl-1 correlate with the extent of synergy, suggesting that cancers with elevated levels of Bcl-x(L) will be relatively resistant to taxane-based therapy but could benefit from the addition of navitoclax to taxane treatment. Finally, a significant percentage of NSCLC patient samples exhibit relatively high Bcl-x(L) levels.
The addition of navitoclax to taxane-based chemotherapy in NSCLC has the potential to increase efficacy, particularly in patients whose tumors express high levels of Bcl-x(L).
3,4-Difluoro-2-(2-fluoro-4-iodo-phenylamino)-phenyl-((S)-3-hydroxy-3-piperidin-2-yl-azetidin-1-yl)-methanone (GDC-0973) is a potent and highly selective inhibitor of mitogen-activated protein ...kinase(MAPK)/extracellular signal-regulated kinase (ERK) 1/2 (MEK1/2), a MAPK kinase that activates ERK1/2. The objectives of these studies were to characterize the disposition of GDC-0973 in preclinical species and to determine the relationship of GDC-0973 plasma concentrations to efficacy in Colo205 mouse xenograft models. The clearance (CL) of GDC-0973 was moderate in mouse (33.5 ml · min(-1) · kg(-1)), rat (37.9 ± 7.2 ml · min(-1) · kg(-1)), and monkey (29.6 ± 8.5 ml · min(-1) · kg(-1)). CL in dog was low (5.5 ± 0.3 ml · min(-1) · kg(-1)). The volume of distribution across species was large, 6-fold to 15-fold body water; half-lives ranged from 4 to 13 h. Protein binding in mouse, rat, dog, monkey, and human was high, with percentage unbound, 1 to 6%. GDC-0973-related radioactivity was rapidly and extensively distributed to tissues; however, low concentrations were observed in the brain. In rats and dogs, (14)CGDC-0973 was well absorbed (fraction absorbed, 70-80%). The majority of (14)CGDC-0973-related radioactivity was recovered in the bile of rat (74-81%) and dog (65%). The CL and volume of distribution of GDC-0973 in human, predicted by allometry, was 2.9 ml · min(-1) · kg(-1) and 9.9 l/kg, respectively. The predicted half-life was 39 h. To characterize the relationship between plasma concentration of GDC-0973 and tumor growth inhibition, pharmacokinetic-pharmacodynamic modeling was applied using an indirect response model. The KC(50) value for tumor growth inhibition in Colo205 xenografts was estimated to be 0.389 μM, and the predicted clinical efficacious dose was ∼10 mg. Taken together, these data are useful in assessing the disposition of GDC-0973, and where available, comparisons with human data were made.
We describe the preclinical pharmacology and antitumor activity of GDC-0068, a novel highly selective ATP-competitive pan-Akt inhibitor currently in clinical trials for the treatment of human ...cancers.
The effect of GDC-0068 on Akt signaling was characterized using specific biomarkers of the Akt pathway, and response to GDC-0068 was evaluated in human cancer cell lines and xenograft models with various genetic backgrounds, either as a single agent or in combination with chemotherapeutic agents.
GDC-0068 blocked Akt signaling both in cultured human cancer cell lines and in tumor xenograft models as evidenced by dose-dependent decrease in phosphorylation of downstream targets. Inhibition of Akt activity by GDC-0068 resulted in blockade of cell-cycle progression and reduced viability of cancer cell lines. Markers of Akt activation, including high-basal phospho-Akt levels, PTEN loss, and PIK3CA kinase domain mutations, correlate with sensitivity to GDC-0068. Isogenic PTEN knockout also sensitized MCF10A cells to GDC-0068. In multiple tumor xenograft models, oral administration of GDC-0068 resulted in antitumor activity ranging from tumor growth delay to regression. Consistent with the role of Akt in a survival pathway, GDC-0068 also enhanced antitumor activity of classic chemotherapeutic agents.
GDC-0068 is a highly selective, orally bioavailable Akt kinase inhibitor that shows pharmacodynamic inhibition of Akt signaling and robust antitumor activity in human cancer cells in vitro and in vivo. Our preclinical data provide a strong mechanistic rationale to evaluate GDC-0068 in cancers with activated Akt signaling.
Alterations of the phosphoinositide-3 kinase (PI3K)/Akt signaling pathway occur broadly in cancer via multiple mechanisms including mutation of the PIK3CA gene, loss or mutation of phosphatase and ...tensin homolog (PTEN), and deregulation of mammalian target of rapamycin (mTOR) complexes. The dysregulation of this pathway has been implicated in tumor initiation, cell growth and survival, invasion and angiogenesis, thus, PI3K and mTOR are promising therapeutic targets for cancer. We discovered GDC-0980, a selective, potent, orally bioavailable inhibitor of Class I PI3 kinase and mTOR kinase (TORC1/2) with excellent pharmacokinetic and pharmaceutical properties. GDC-0980 potently inhibits signal transduction downstream of both PI3K and mTOR, as measured by pharmacodynamic (PD) biomarkers, thereby acting upon two key pathway nodes to produce the strongest attainable inhibition of signaling in the pathway. Correspondingly, GDC-0980 was potent across a broad panel of cancer cell lines, with the greatest potency in breast, prostate, and lung cancers and less activity in melanoma and pancreatic cancers, consistent with KRAS and BRAF acting as resistance markers. Treatment of cancer cell lines with GDC-0980 resulted in G1 cell-cycle arrest, and in contrast to mTOR inhibitors, GDC-0980 induced apoptosis in certain cancer cell lines, including those with direct pathway activation via PI3K and PTEN. Low doses of GDC-0980 potently inhibited tumor growth in xenograft models including those with activated PI3K, loss of LKB1 or PTEN, and elicited an exposure-related decrease in PD biomarkers. These preclinical data show that GDC-0980 is a potent and effective dual PI3K/mTOR inhibitor with promise for the clinic.
The phosphatidylinositol 3-kinase (PI3K)-Akt signaling pathway is frequently disrupted in cancer and implicated in multiple aspects of tumor growth and survival. In addition, increased activity of ...this pathway in cancer is associated with resistance to chemotherapeutic agents. Therefore, it has been hypothesized that PI3K inhibitors could help to overcome resistance to chemotherapies. We used preclinical cancer models to determine the effects of combining the DNA-damaging drug doxorubicin with GDC-0941, a class I PI3K inhibitor that is currently being tested in early-stage clinical trials. We found that PI3K inhibition significantly increased apoptosis and enhanced the antitumor effects of doxorubicin in a defined set of breast and ovarian cancer models. Doxorubicin treatment caused an increase in the amount of nuclear phospho-Akt(Ser473) in cancer cells that rely on the PI3K pathway for survival. This increased phospho-Akt(Ser473) response to doxorubicin correlates with the strength of GDC-0941's effect to augment doxorubicin action. These studies predict that clinical use of combination therapies with GDC-0941 in addition to DNA-damaging agents will be effective in tumors that rely on the PI3K pathway for survival.
Abstract
Background: Akt, a serine/threonine protein kinase, and MEK, a dual specificity kinase, are key signaling nodes in the PI3K/Akt/mTOR and the Ras/Raf/MAPK pathway, respectively. Both Akt and ...MEK play key roles in regulating numerous cellular processes such as cell proliferation, growth, survival, protein synthesis and oncogenic transformation. Many cancer types have alterations in both of these pathways and inhibiting only one of these pathways can result in up-regulation of the other pathway. We previously reported on a potent highly selective ATP-competitive pan-Akt inhibitor, GDC-0068 as well as a potent selective inhibitor of MEK, GDC-0973 that are currently in Phase 1 clinical trials. We hypothesized that dual inhibition of both MEK and Akt pathways with the combination of these two agents would induce synergistic antitumor activity. Methods: In these studies, we evaluated the efficacy of GDC-0068 and GDC-0973 both individually and in combination on a panel of cancer cell lines. Cells were treated with either GDC-0068 or GDC-0973 or in combination at increasing concentrations and assayed after 4 days for viability. For in vivo studies, tumor cells were subcutaneously implanted in the flank of female NCR.nude mice. Once tumors reached sufficient size, mice were dosed orally for 21 days with GDC-0068, GDC-0973 or the combination of both compounds. Results: In vitro, the combination of GDC-0068 and GDC-0973 results in enhanced inhibition of cell viability compared to either single agent alone. Synergistic effects are observed in multiple cell lines; especially in cell lines that have activation of the Ras/Raf/MAPK pathway or both pathways (e.g. via the combination of PTEN loss or PI3K mutations and Ras or BRaf mutations). Combined knockdown of downstream targets of both Akt and MEK is observed at concentrations where a synergistic effect is observed, with enhanced knockdown of several converged targets. Increased cell death is also observed. These results were recapitulated in vivo in xenograft models, where the combination of GDC-0068 and GDC-0973 resulted in increased tumor growth inhibition or regression compared to either single agent alone. All combinations tested were well tolerated as assessed by animal body weights and mortalities. Conclusions: Our studies demonstrate significant combination benefit between GDC-0068 and GDC-0973 on cell viability in vitro and tumor growth in vivo. These data support the clinical development of the combination of these two compounds.
Citation Format: {Authors}. {Abstract title} abstract. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 873. doi:1538-7445.AM2012-873
Abstract
Navitoclax (formerly ABT-263), a potent inhibitor of Bcl-2, Bcl-xL, and Bcl-w, has shown promising activity in CLL, a disease in which Bcl-2 is highly expressed. In this study, we wished to ...explore its potential as a Bcl-xL inhibitor. Bcl-xL is thought to contribute to resistance to cancer therapy in epithelial cancers. Navitoclax and the related molecule, ABT-737, potentiate the activity of chemotherapy and targeted agents in cell lines and mouse models. In order to identify predictive biomarkers of synergy and identify combinations most likely to translate to the clinical setting, we performed combination studies on a panel of 100 cell lines derived from breast, lung, ovarian and pancreatic cancer. We evaluated the combination of navitoclax with gemcitabine, paclitaxel, as well as targeted agents that inhibit EGFR, phosphatidylinositol-3-kinase and MAP kinase pathways. These studies demonstrate that navitoclax is broadly synergistic with these agents as evaluated by a Bliss independence model. The majority of cell lines and combinations exhibited Bliss scores that exceeded the values predicted for two independent agents. Correlative marker analysis revealed that levels of proteins within the Bcl-2 family correlated with synergy scores for chemotherapy combinations, while activation of the EGFR/Ras/Raf pathway was a better predictor for the combinations of navitoclax with targeted agents. Combination studies in xenograft models demonstrate that navitoclax can enhance the activity of chemotherapy and targeted agents in vivo. Furthermore, biomarker expression correlated with response in vivo. These studies suggest distinct strategies for patient selection that are dependent upon the combination agent.
Citation Format: {Authors}. {Abstract title} abstract. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3151. doi:10.1158/1538-7445.AM2011-3151
We report the discovery of a series of 4-aryl-2-aminoalkylpyrimidine derivatives as potent and selective JAK2 inhibitors. High throughput screening of our in-house compound library led to the ...identification of hit 1, from which optimization resulted in the discovery of highly potent and selective JAK2 inhibitors. Advanced lead 10d demonstrated a significant dose-dependent pharmacodynamic and antitumor effect in a mouse xenograft model. Based upon the desirable profile of 10d (XL019) it was advanced into clinical trials.
Abstract
Navitoclax (formerly ABT-263) is a small molecule that potently antagonizes the activity of Bcl-2, Bcl-xL, and Bcl-w. To determine the potential of this molecule in combination with ...taxane-based chemotherapy, we evaluated a panel of 33 human NSCLC cell lines with a dose matrix of paclitaxel and navitoclax. All cell lines exhibited a greater than additive response to the combination, suggesting a synergistic interaction. These results were extended to mouse xenograft tumor models, in which the combination was more efficacious than either single agent docetaxel or navitoclax. Live cell time-lapse microscopy was used to demonstrate that the addition of navitoclax to paclitaxel decreases the time from mitotic entry to cell death and changes cell fate from mitotic slippage to death during mitotic arrest. The relative levels of Bcl-xL and Mcl-1 correlate with the extent of synergy as measured by a Bliss independence model, suggesting that cancers with high levels of Bcl-xL will be relatively resistant to taxane-based therapy, but could benefit from addition of navitoclax to taxane treatment. Finally, a significant percentage of NSCLC patient samples exhibit high Bcl-xL levels, indicating the potential for broad utility of this combination in lung cancer.
Treatment for survivors of incest Hall, Robert P.; Kassees, Joanne M.; Hoffman, Chrisann
The Journal for specialists in group work,
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Journal Article
Recenzirano
Directed self-help, mutual support groups are useful resources for the treatment of various populations victimized by sexual abuse. Several group models are presented.
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