Effects of tamoxifen on the endometrium and its mechanism of carcinogenicity

Bioelectric pharmacology of cancer: A systematic review of ion channel drugs affecting the cancer phenotype

Cancer is a pernicious and pressing medical problem; moreover, it is a failure of multicellular morphogenesis that sheds much light on evolutionary developmental biology. Numerous classes of pharmacological agents have been considered as cancer therapeutics and evaluated as potential carcinogenic agents; however, these are spread throughout the primary literature. Here, we briefly review recent work on ion channel drugs as promising anti-cancer treatments and present a systematic review of the known cancer-relevant effects of 109 drugs targeting ion channels. The roles of ion channels in cancer are consistent with the importance of bioelectrical parameters in cell regulation and with the functions of bioelectric signaling in morphogenetic signals that act as cancer suppressors. We find that compounds that are well-known for having targets in the nervous system, such as voltage-gated ion channels, ligand-gated ion channels, proton pumps, and gap junctions are especially relevant to cancer. Our review suggests further opportunities for the repurposing of numerous promising candidates in the field of cancer electroceuticals.

The Role of Immunohistochemistry Markers in Endometrial Cancer with Mismatch Repair Deficiency: A Systematic Review

The objective of this systematic review was to summarize our current knowledge of the role of immunohistochemistry (IHC) markers for identifying mismatch repair-deficient (MMRd) tumors in endometrial cancer (EC). Identification of MMRd tumors, which occur in 13% to 30% of all ECs, has become critical for patients with colorectal and endometrial cancer for therapeutic management, clinical decision making, and prognosis. This review was conducted by two authors applying the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines using the following terms: “immunohistochemistry and microsatellite instability endometrial cancer” or “immunohistochemistry and mismatch repair endometrial cancer” or “immunohistochemistry and mismatch repair deficient endometrial cancer”. Among 596 retrieved studies, 161 fulfilled the inclusion criteria. Articles were classified and presented according to their interest for the diagnosis, prognosis, and theragnostics for patients with MMRd EC. We identified 10, 18, and 96 articles using IHC expression of two, three, or four proteins of the MMR system (MLH1, MSH2, MHS6, and PMS2), respectively. MLH1 promoter methylation was analyzed in 57 articles. Thirty-four articles classified MMRd tumors with IHC markers according to their prognosis in terms of recurrence-free survival (RFS), overall survival (OS), stage, grade, and lymph node invasion. Theragnostics were studied in eight articles underlying the important concentration of PD-L1 in MMRd EC. Even though the role of IHC has been challenged, it represents the most common, robust, and cheapest method for diagnosing MMRd tumors in EC and is a valuable tool for exploring novel biotherapies and treatment modalities.

Anticancer activity, apoptosis and a structure-activity analysis of a series of 1,4-naphthoquinone-2,3-bis-sulfides

We have previously reported on the synthesis of 1,4-naphthoquinone-sulfides and in this investigation we report on their anticancer activity against 6 human cancer cell lines to evaluate their cytostatic effects. The 1,4-naphthoquinone-2,3-bis-sulfides were most effective against melanoma (UACC62) (GI₅₀ = 6.5-10 μM) and prostate (PC3) (GI₅₀ = 5.51-8.53 μM) cancer cell lines. They exhibited better cytostatic effects than etoposide (GI₅₀ = 0.56-36.62 μM), parthenolide (GI₅₀ = 3.58-25.97 μM) and VK3 (GI₅₀ = 3.41-22.59 μM) against several of the cancer cell lines. These compounds are generally more selective for cancer cells than for normal human lung fetal fibroblasts (WI-38). One compound produces ROS which results in breast (MCF7) cancer cell death caused by apoptosis as evidenced by caspase 3/7 activation. Apoptosis was found to occur by a mitochondrial pathway and not by cell cycle arrest. Gene expression studies showed that p53 (a tumour suppressor), Mdm-2 (a p53 regulator) and Bcl-2 (apoptosis inhibitor) were up-regulated during apoptosis induction. These results encourage further research for potential application in cancer chemotherapy.

Proteomics profiling identify CAPS as a potential predictive marker of tamoxifen resistance in estrogen receptor positive breast cancer

Background

Despite the success of tamoxifen since its introduction, about one-third of patients with estrogen (ER) and/or progesterone receptor (PgR) - positive breast cancer (BC) do not benefit from therapy. Here, we aim to identify molecular mechanisms and protein biomarkers involved in tamoxifen resistance.

Results

Using iTRAQ and Immobilized pH gradient-isoelectric focusing (IPG-IEF) mass spectrometry based proteomics we compared tumors from 12 patients with early relapses (<2 years) and 12 responsive to therapy (relapse-free > 7 years). A panel of 13 proteins (TCEAL4, AZGP1, S100A10, ALDH6A1, AHNAK, FBP1, S100A4, HSP90AB1, PDXK, GFPT1, RAB21, MX1, CAPS) from the 3101 identified proteins, potentially separate relapse from non-relapse BC patients. The proteins in the panel are involved in processes such as calcium (Ca²⁺) signaling, metabolism, epithelial mesenchymal transition (EMT), metastasis and invasion. Validation of the highest expressed proteins in the relapse group identify high tumor levels of CAPS as predictive of tamoxifen response in a patient cohort receiving tamoxifen as only adjuvant therapy.

Conclusions

This data implicate CAPS in tamoxifen resistance and as a potential predictive marker.

Electronic supplementary material

The online version of this article (doi:10.1186/s12014-015-9080-y) contains supplementary material, which is available to authorized users.

Molecular mechanisms of tamoxifen-associated endometrial cancer (Review)

Tamoxifen has been prescribed to millions of females for breast cancer prevention or treatment. However, tamoxifen is known to significantly enhance the risk of developing endometrial lesions, including hyperplasia, polyps, carcinomas, and sarcoma. Notably, tamoxifen-associated endometrial cancer often has a poor clinical outcome. Understanding the molecular mechanism of tamoxifen-induced endometrial cancer is essential for developing strategies that minimize tamoxifen’s effects on the endometrium without jeopardizing its breast cancer treatment effects. However, this understanding remains limited. Tamoxifen appears to mediate its effect on endometrial cells through estrogenic and non-genomic pathways, rather than introducing a genomic alteration as a carcinogen. Although tamoxifen functions as an agonist and promotes cell proliferation in endometrial cancer, it also displays antagonist activity towards some estrogen targets. Alterations in estrogen receptor-α and its isoforms, as well as the membrane associated estrogen receptor G protein-coupled receptor 30, have been observed with tamoxifen-exposed endometrial cells, and likely mediate the effects of tamoxifen on endometrial cancer cell proliferation and invasion. In addition, gene profile studies of short-term exposure to tamoxifen indicate that the majority of tamoxifen targets are tamoxifen-specific. However, the tamoxifen regulated gene targets that are involved in mediating the effects of long-term exposure to tamoxifen are not yet fully understood. Recent progress has indicated a potential role of unfolded protein response and mammalian target of rapamycin signaling in tamoxifen-associated endometrial cancer. In the future, studies focusing on long-term effects of tamoxifen exposure are required to understand the molecular mechanisms of tamoxifen-associated endometrial cancer.

[Third generation selective estrogen receptor modulators: benefits beyond bone. II, endometrial action]

The selective estrogen receptor modulators (SERMs) are substances with estrogenic/anti-estrogen effect that act differently depending on the tissue and composition. Since the discovery that tamoxifen and raloxifene (RLX) had a breast cancer preventive effect, the search for the perfect SERM has been the goal. The evidence that tamoxifen significantly increased the risk of endometrial cancer as compared to placebo made this tissue the center of interest in developing new SERMs. Thus, ospemifen, arzoxifene, lasofoxifene (LFX) and bazedoxifene (BZA) appeared as third-generation SERMs but only BZA reached the stage of clinical use. Both experimental and clinical data available on the effects of RLX or third-generation SERMs reaching clinical stage (LFX and BZA) show either neutrality or anti-estrogenic effects at endometrial level. BZA has shown to be equivalent to vehicle in several experimental conditions and acts as anti-estrogen in models were estrogens (conjugated equine estrogens [CEE] or E2) were co-administered. In a 7 years pivotal study the incidence of endometrial adenocarcinoma has been significantly lower in the BZA than in the placebo group. Moreover, in a clinical trial to evaluate the ability of a combination of BZA and CEE to prevent hot flushes in symptomatic postmenopausal women, doses of 20mg or higher of BZA have significantly decreased the risk of presenting endometrial hyperplasia when co-administered with either 0.650 or 0.450mg of CEE.

Analysis of the expression of angiotensin II type 1 receptor and VEGF in endometrial adenocarcinoma with different clinicopathological characteristics

In Poland, endometrial carcinoma takes second place after breast cancer among all cancers in women and is considered the most common genital cancer. It has been repeatedly reported that angiotensin is involved in the development and invasion of some cancers including breast, ovarian, and pancreatic ones. It is suggested that angiotensin two and its receptors are actively involved in tumour biology in endometrial adenocarcinoma. In the present study, we identify a possible relationship between the expression of AT1-R, AT2-R, ERα, and VEGF and clinicopathological characteristics of primary endometrial adenocarcinoma. We determined the above components both at the mRNA (real-time RT-PCR) and protein levels (Western Blot assay). Our results indicate that in patients with grade G3 adenocarcinoma, the expression of AT1-R significantly decreased in comparison with G1 patients (p = 0.034), but the level of ERα was the highest in G2 and the lowest in G3. Moreover, the level of VEGF mRNA significantly increased between G2 and G3 (p = 0.034). We also noted a significant correlation between the expression of AT1-R and AT2-R in FIGO stage 1 (R (s) = 0.9636; p = 0.0001) and that of AT2-R and VEGF (R (s) = 0.5377; p = 0.005). In grade G1 and G2 carcinoma, a significant correlation was also found between the expression of AT1-R and AT2-R (R (s) = 0.9924; p = 0.0001; R (s) = 0.8717, p = 0.0005, respectively), but in grade G1, a negative correlation was observed between AT1-R and VEGF (R (s) = -0.8945, p = 0.0005). Further studies are required to clarify the biological function of the angiotensin receptor in regulating VEGF expression in endometrial carcinoma.