Cancer stem cells (CSC) are the primary cell type responsible for metastasis and relapse. ABC-transporters are integral membrane proteins involved in the translocation of substrates across membranes protecting CSC from chemotherapeutic agents. A plant extract derived from C. spinosa (P2Et) previously investigated for its antitumor activity has been shown to reduce lung and spleen metastasis in mice that have been transplanted with breast cancer cells, suggesting that P2Et has a significant activity against cancer stem cells (CSC). P2Et extract was thoroughly characterized by HPLC/MS. The cytotoxicity of P2Et extract was evaluated using a MTT assay in human and murine cell lines with different profiles of resistance, by Pgp overexpression or by enrichment in cancer stem cells. The synergistic effect of P2Et with doxorubicin was evaluated in vitro in several cell lines and in vivo in mice transplanted with TS/A cells, a highly resistant cell line and enriched in CD44${}^{\mathrm{\text{+}}}$CD24${}^{\mathrm{\text{low/-}}}$CSC. The chromatographic fingerprint of P2Et extract revealed 13 gallotannins. We also found that P2Et extract was cytotoxic to cells regardless of their resistant phenotype. Similarly, complementary activities were observed as drug efflux reversion and antioxidant activity. Short-treatment with P2Et extract, revealed a synergistic effect with doxorubicin in resistant cell lines. In vivo the P2Et increases mice survival in a TS/A breast cancer model associated with augmentation of calreticulin expression. Our results suggest that P2Et treatment could be used as adjuvant along with conventional chemotherapy to treat tumors with a MDR phenotype or with high frequency of CSC.

Raw milk adulteration with cheese whey is a major problem that affects the dairy industry. The objective of this work was to evaluate the adulteration of raw milk with the cheese whey obtained from the coagulation process, with chymosin enzyme using casein glycomacropeptide (cGMP) as an HPLC marker. Milk proteins were precipitated with 24% TCA; with the supernatant obtained, a calibration curve was established by mixing raw milk and whey in different percentages, which were passed through a KW-802.5 Shodex molecular exclusion column. A reference signal, with a retention time of 10.8 min, was obtained for each of the different percentages of cheese whey; the higher the concentration, the higher the peak. Data analysis was adjusted to a linear regression model, with an R² of 0.9984 and equation to predict dependent variable (cheese whey percentage in milk) values. The chromatography sample was collected and analyzed by three tests: a cGMP standard HPLC analysis, MALDI-TOF spectrometry, and immunochromatography assay. The results of these three tests confirmed the presence of the cGMP monomer in adulterated samples with whey, which was obtained from chymosin enzymatic coagulation. As a contribution to food safety, the molecular exclusion chromatography technique presented is reliable, easy to implement in a laboratory, and inexpensive, compared with other methodologies, such as electrophoresis, immunochromatography, and HPLC-MS, thus allowing for the routine quality control of milk, an important product in human nutrition.