Human breast tumors that are initially responsive to tamoxifen (TAM) eventually relapse during treatment. Estrogen receptor (ER) expression and function are often preserved in these tumors, and clinical evidence suggests that this relapse may be related to TAM's known agonistic properties. ER can interact with the activator protein-1 (AP-1) transcription factor complex through protein-protein i...

We have performed isobologram analyses of the ability of tamoxifen (TAM) to alter the response to Adriamycin (ADR) and vinblastine (VBL) in human breast cancer cells. MCF-7 cells express functional receptors for estrogen and progesterone but do not express detectable levels of M(r) 170,000 glycoprotein (gp170). CL 10.3 and MCF-7ADR cells are MCF-7 variants which express gp170. CL 10.3 but not M...

Trans-tamoxifen (TAM) has been used successfully in therapy for estrogen-dependent human breast tumors and prevention of their recurrence. The mechanism of this prevention was thought to be due to the interference of TAM with estrogen promotion. TAM has a wider anticarcinogenic action that is similar to other chemopreventive agents in that it suppresses tumor promotion in 2-stage carcinogenesis...

The clinical significance of regulatory T cells (Treg) and tumor-associated macrophages (TAM) in the tumor microenvironment of human bladder cancer remains unclear. The aim of this study is to explore their relevance to oncological features in non-muscle invasive bladder cancer (NMIBC). We carried out immunohistochemical analysis of forkhead box P3 (FOXP3, Treg maker), CD204 (TAM marker), and i...

Tamoxifen (TAM) is the mainline drug treatment for breast cancer, despite its side effects and the development of resistance. As an alternative approach, in the present study a novel combination therapy was established through combining TAM with nordamnacanthal (NDAM) in order to investigate the additive effect of these drugs in MCF-7 human breast cancer cells. A significant dose-dependent redu...

In recent years, the influence of the tumor microenvironment (TME) on cancer progression has been better understood. Macrophages, one of the most important cell types in the TME, exist in different subtypes, each of which has a different function. While classically activated M1 macrophages are involved in inflammatory and malignant processes, activated M2 macrophages are more involved in the wo...

The development of acquired resistance to antihormonal agents in breast cancer is a major therapeutic problem. We have developed a tamoxifen-resistant (TAM-R) MCF-7 breast cancer cell line to investigate the mechanisms behind this condition. Both epidermal growth factor receptor (EGFR) and c-erbB2 mRNA and protein expression were increased in TAM-R compared with wild-type MCF-7 cells, whereas c...

ABstRAct The technology acceptance model (TAM) is a popular model for the prediction of information systems acceptance behaviors, defining a causal linkage between beliefs, attitudes, intentions, and the usage of information technologies. Since its inception, numerous studies have utilized the TAM, providing empirical support for the model in both traditional and Internet-based computing settin...

Tamoxifen (TAM) is the most widely used endocrine therapy for estrogen receptor (ER)-positive breast cancer patients, but side effects and the gradual development of insensitivity limit its application. We investigated whether Huaier extract, a traditional Chinese medicine, in combination with TAM would improve treatment efficacy in ER-positive breast cancers. MTT, colony formation, and invasio...

The formation of tamoxifen (TAM)-derived DNA adducts was investigated by incubation of DNA with (E)-alpha-hydroxytamoxifen [(E)-alpha-OHTAM], 3'-phosphoadenosine 5'-phosphosulfate (PAPS), and human recombinant sulfotransferase. Using 32P-post-labeling and HPLC analysis, two TAM-DNA adducts were detected in incubations that included the human hydroxysteroid sulfotransferase SULT2A1 (hHST). When ...