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Abstract: This article describes the antitumor properties of a new family of merosesquiterpenes, which were synthesized by Diels–Alder cycloaddition of the labdane diene trans-communic acid, highly abundant in Cupressus sempervirens, or its methyl ester, with the appropriate dienophile. These compounds demonstrated potent cytotoxic activity in vitro against human breast, colon, and lung tumor cells. We highlight the elevated activity (IC50: 0.35 ± 0.10 μM) and specificity (TI: 9) of compound 13 against the MCF-7 line, which corresponds to the most prevalent breast cancer cell subtype, luminal A. It was found that compound 13 exerts its anti-tumor action by inducing oxidative stress, arresting the cell cycle in stages G0–G1, and activating apoptosis, which are all associated with low cyclin D1 regulation, pRb hypophosphorylation, increased expression of p27 and p53, and poly (ADP-ribose) polymerase (PARP) fractioning. Epithelial–mesenchymal transition, a phenomenon associated with metastasis promotion and a worsened prognosis also appeared to be inhibited by compound 13 . In addition, it markedly reduced tumor development in immunocompetent C57BL/6 mice with allografts of E0771 mouse breast tumor cells (luminal A subtype). According to these findings, this new family of compounds, especially compound 13 , may be highly useful in the treatment of human breast cancer. [Copyright &y& Elsevier]

Introduction: Recently, we have reported the antitumor properties of a new family of synthetic merosesquiterpenes, among which meroxest is highlighted, since it has high activity and specificity for ER+ breast cancer cells. In this paper, we characterize allografts of ER+ E0771 mouse breast tumor cells in immunocompetent C57BL/6 mice, and also analyze the effect of meroxest on the prognosis of the disease.Material and Methods: Twenty female C57BL/6 mice were injected with 106 E0771 cells. Once the tumors reached the appropriate size, the mice were divided into two groups, one control and another treated orally with 15 mg/kg of meroxest. After 20 days, tumor samples were taken for histopathological study and for determination of the expression of the prognostic markers Ki67 and vascular endothelial growth factor (VEGF) by immunofluorescence.Results: In sections stained with hematoxylin-eosin, we observed that tumors have a well-defined capsule enclosing E0771 tumor cells. The central area of tumors contains necrotic regions with leukocyte infiltration. Meroxest treatment significantly reduces tumor size (68%, p < 0.05), induces changes in its structure, decreases the degree of leukocyte infiltration, and significantly reduces the expression of Ki67 (33%, p < 0.05) and VEGF (82%, p < 0.05).Conclusions: Meroxest improves the prognosis of mice since it reduces leukocyte infiltration, and decreases the expression of Ki67 and VEGF markers. Consequently, the merosesquiterpene could become a useful antiangiogenic drug in the treatment of breast cancer. These results encourage us to deepen the study of meroxest, in order to find more evidence that supports the convenience of its evaluation in a clinical study or trial. [ABSTRACT FROM AUTHOR]

Background: New biomarkers are needed for the prognosis of advanced colorectal cancer, which remains incurable by conventional treatments. O6-methylguanine DNA methyltransferase (MGMT) methylation and protein expression have been related to colorectal cancer treatment failure and tumor progression. Moreover, the presence in these tumors of cancer stem cells, which are characterized by CD133 expression, has been associated with chemoresistance, radioresistance, metastasis, and local recurrence. The objective of this study was to determine the prognostic value of CD133 and MGMT and their possible interaction in colorectal cancer patients. Methods: MGMT and CD133 expression was analyzed by immunohistochemistry in 123 paraffin-embedded colorectal adenocarcinoma samples, obtaining the percentage staining and intensity. MGMT promoter methylation status was obtained by using bisulfite modification and methylation-specific PCR (MSP). These values were correlated with clinical data, including overall survival (OS), disease-free survival (DFS), tumor stage, and differentiation grade. Results: Low MGMT expression intensity was significantly correlated with shorter OS and was a prognostic factor independently of treatment and histopathological variables. High percentage of CD133 expression was significantly correlated with shorter DFS but was not an independent factor. Patients with low-intensity MGMT expression and =50% CD133 expression had the poorest DFS and OS outcomes. Conclusions: Our results support the hypothesis that MGMT expression may be an OS biomarker as useful as tumor stage or differentiation grade and that CD133 expression may be a predictive biomarker of DFS. Thus, MGMT and CD133 may both be useful for determining the prognosis of colorectal cancer patients and to identify those requiring more aggressive adjuvant therapies. Future studies will be necessary to determine its clinical utility. [ABSTRACT FROM AUTHOR]

Background: New biomarkers are needed for the prognosis of advanced colorectal cancer, which remains incurable by conventional treatments. O6-methylguanine DNA methyltransferase (MGMT) methylation and protein expression have been related to colorectal cancer treatment failure and tumor progression. Moreover, the presence in these tumors of cancer stem cells, which are characterized by CD133 expression, has been associated with chemoresistance, radioresistance, metastasis, and local recurrence. The objective of this study was to determine the prognostic value of CD133 and MGMT and their possible interaction in colorectal cancer patients. Methods: MGMT and CD133 expression was analyzed by immunohistochemistry in 123 paraffin-embedded colorectal adenocarcinoma samples, obtaining the percentage staining and intensity. MGMT promoter methylation status was obtained by using bisulfite modification and methylation-specific PCR (MSP). These values were correlated with clinical data, including overall survival (OS), disease-free survival (DFS), tumor stage, and differentiation grade. Results: Low MGMT expression intensity was significantly correlated with shorter OS and was a prognostic factor independently of treatment and histopathological variables. High percentage of CD133 expression was significantly correlated with shorter DFS but was not an independent factor. Patients with low-intensity MGMT expression and ≥50% CD133 expression had the poorest DFS and OS outcomes. Conclusions: Our results support the hypothesis that MGMT expression may be an OS biomarker as useful as tumor stage or differentiation grade and that CD133 expression may be a predictive biomarker of DFS. Thus, MGMT and CD133 may both be useful for determining the prognosis of colorectal cancer patients and to identify those requiring more aggressive adjuvant therapies. Future studies will be necessary to determine its clinical utility. [ABSTRACT FROM AUTHOR]