The arrival of predictive biomarkers for monitoring therapy response to natural compounds in cancer drug discovery

Intrinsic or acquired drug resistance, adverse drug reactions and tumor heterogeneity between and within cancer patients limit the efficacy of clinical management of advanced cancers. To overcome these barriers, predictive biomarkers have recently emerged to guide medical oncologists in the selection of cancer patients who will respond to various anticancer treatments and to improve the toxicity to benefit ratio. Notably, targeted therapy has significantly benefited from these advances, but the application of predictive biomarkers have been a bit slower with some drugs derived from natural sources such as trabectedin, cabazitaxel and alvocidib. In this paper, we discuss some recent advances regarding the use of cancer biomarkers to predict efficacy of some selected natural compounds with a focus on human clinical studies.

The arrival of predictive biomarkers for monitoring therapy response to natural compounds in cancer drug discovery

Intrinsic or acquired drug resistance, adverse drug reactions and tumor heterogeneity between and within cancer patients limit the efficacy of clinical management of advanced cancers. To overcome these barriers, predictive biomarkers have recently emerged to guide medical oncologists in the selection of cancer patients who will respond to various anticancer treatments and to improve the toxicity to benefit ratio. Notably, targeted therapy has significantly benefited from these advances, but the application of predictive biomarkers have been a bit slower with some drugs derived from natural sources such as trabectedin, cabazitaxel and alvocidib. In this paper, we discuss some recent advances regarding the use of cancer biomarkers to predict efficacy of some selected natural compounds with a focus on human clinical studies.

Comprehensive Analysis of the Chemical Composition and In Vitro Cytotoxic Mechanisms of Pallines Spinosa Flower and Leaf Essential Oils Against Breast Cancer Cells

BACKGROUND/AIMS

In our quest for new natural anticancer agents, we studied the cytotoxicity of the essential oils extracted from flowers and leaves of Pallines spinosa.

METHODS

The essential oils were extracted by hydrodistillation and solid phase microextraction (SPME) from flowers and leaves of the plant and their composition was determined by GC/GC-MS. The cytotoxicity of the oils was evaluated against MCF-7 and MDA-MB-231 breast adenocarcinomas, and the non-cancerous MCF-10-2A cells, using a flow cytometry-based assay Apoptosis was evaluated by flow cytometry, nuclear staining, caspases activation, and Western blotting techniques, and cell cycle by measuring DNA contents.

RESULTS

The hydrodistilled flower oil contained mainly sesquiterpenes (96.39%), while the leaf sample was dominated by oxygenated-sesquiterpenes (51.60%) and sesquiterpene-hydrocarbons (34.06%). In contrast, the SPME oil contained mainly monoterpene-hydrocarbons (44.09%) and sesquiterpene-hydrocarbons (34.15%) in the flower and leaf samples, respectively. The cytotoxicity of the flower oil against MCF-7 (IC50 0.25 ± 0.03 µg/mL) and MDA-MB-231 (IC50 0.21 ± 0.03 µg/mL) was much stronger than the leaf oil (IC50 2.4 ± 0.5 µg/mL and 1.5 ± 0.1 µg/mL, respectively). The toxicity of the flower oil was ∼5 to 8-times less in normal MCF-10-2A (IC50 1.3 ± 0.2 µg/mL) and blood mononuclear cells (2.80 ± 0.45 µg/mL) as compared to breast and hematological cancer cells, respectively. Both oils induced a caspase-dependent and -independent apoptosis in MCF-7 and MDA-MB-231 cells, and altered the levels of Bcl-2 and Bax proteins. In addition, the oils arrested cell cycle in both cancer cell lines at G0/G1 phase by modulating the expression of cyclin D1, CDK4 and p21 proteins.

CONCLUSION

The cytotoxicity of P. spinosa oils were mediated by apoptosis and cell cycle arrest, suggesting the potential use of their bioactive compounds as natural anticancer compounds.