This review presents new findings on Wnt signaling in endometrial carcinoma and implications for possible future treatments. The Wnt proteins are essential mediators in cell signaling during vertebrate embryo development. Recent biochemical and genetic studies have provided significant insight into Wnt signaling, in particular in cell cycle regulation, inflammation, and cancer. The role of Wnt signaling is well established in gastrointestinal and breast cancers, but its function in gynecologic cancers, especially in endometrial cancers, has not been well elucidated. Development of a subset of endometrial carcinomas has been attributed to activation of the APC/β-catenin signaling pathway (due to β-catenin mutations) and downregulation of Wnt antagonists by epigenetic silencing. The Wnt pathway also appears to be linked to estrogen and progesterone, and new findings implicate it in mTOR and Hedgehog signaling. Therapeutic interference of Wnt signaling remains a significant challenge. Herein, we discuss the Wnt-activating mechanisms in endometrial cancer and review the current advances and challenges in drug discovery.

Sulforaphane exerts anti-cancer activity against multiple cancer types. Our objective was to evaluate utility of sulforaphane for endometrial cancer therapy. Sulforaphane reduced viability of endometrial cancer cell lines in association with the G₂/M cell cycle arrest and cell division cycle protein 2 (Cdc2) phosphorylation, and intrinsic apoptosis. Inhibition of anchorage-independent growth, invasion, and migration of the cell lines was associated with sulforaphane-induced alterations in epithelial-to-mesenchymal transition (EMT) markers of increased E-cadherin and decreased N-cadherin and vimentin expression. Proteomic analysis identified alterations in AKT, mTOR, and ERK kinases in the networks of sulforaphane effects in the Ishikawa endometrial cancer cell line. Western blots confirmed sulforaphane inhibition of AKT, mTOR, and induction of ERK with alterations in downstream signaling. AKT and mTOR inhibitors reduced endometrial cancer cell line viability and prevented further reduction by sulforaphane. Accumulation of nuclear phosphorylated ERK was associated with reduced sensitivity to the ERK inhibitor and its interference with sulforaphane activity. Sulforaphane induced apoptosis-associated growth inhibition of Ishikawa xenograft tumors to a greater extent than paclitaxel, with no evidence of toxicity. These results verify sulforaphane’s potential as a non-toxic treatment candidate for endometrial cancer and identify AKT, mTOR, and ERK kinases in the mechanism of action with interference in the mechanism by nuclear phosphorylated ERK.

Endometrial cancer patients with advanced disease or high recurrence risk are treated with chemotherapy. Our objective was to evaluate the utility and mechanism of a novel drug, SHetA2, alone and in combination with paclitaxel, in endometrial cancer. SHetA2 targets the HSPA chaperone proteins, Grp78, hsc70, and mortalin, which have high mutation rates in endometrial cancer. SHetA2 effects on cancerous phenotypes, mitochondria, metabolism, protein expression, mortalin/client protein complexes, and cell death were evaluated in AN3CA, Hec13b, and Ishikawa endometrial cancer cell lines, and on growth of Ishikawa xenografts. In all three cell lines, SHetA2 inhibited anchorage-independent growth, migration, invasion, and ATP production, and induced G1 cell cycle arrest, mitochondrial damage, and caspase- and apoptosis inducing factor (AIF)-mediated apoptosis. These effects were associated with altered levels of proteins involved in cell cycle regulation, mitochondrial function, protein synthesis, endoplasmic reticulum stress, and metabolism; disruption of mortalin complexes with mitochondrial and metabolism proteins; and inhibition of oxidative phosphorylation and glycolysis. SHetA2 and paclitaxel exhibited synergistic combination indices in all cell lines and exerted greater xenograft tumor growth inhibition than either drug alone. SHetA2 is active against endometrial cancer cell lines in culture and in vivo and acts synergistically with paclitaxel.

Endometrial cancer is the most common female cancer showing continuous rise in its incidence and mortality rate. Despite the extensive research efforts in cancer therapeutics, still there is a lack of effective treatment options and the outcome is poor for patients with advanced and recurrent endometrial cancers. In this study, we aimed to evaluate the efficacy of niclosamide (NIC) against endometrial cancer. NIC is an FDA-approved anti-helminthic drug, which has been recently extensively studied as a potent anti-cancerous agent in several cancers. The anti-cancerous activity of NIC was analyzed in-vitro (ANC3A, Hec1B, and Ishikawa endometrial cancer cell lines) by cell viability-, soft agar-, invasion- and migration- assay. The action mechanism of NIC was demonstrated by western blot analysis and immune-fluorescence imaging and validated by specific inhibitors. The in-vivo efficacy of NIC was studied in the Ishikawa xenograft animal model. NIC effectively suppressed the viability (IC_50<1 μM), colony formation ability, migration, and invasion of all endometrial cancer cells tested. We demonstrated that NIC inhibited AKT/mTOR signaling pathway and induced apoptosis and autophagy in endometrial cancer cells. Further study demonstrated that although NIC induced autophagosome formation, it inhibits autolysosome formation. In addition, we observed that NIC induced BAX co-localization with lysosome and inhibited Cathepsin B maturation from pro-cathepsin B, thereby inducing the lysosomal membrane permeability and release of hydrolytic enzymes from the lysosome to cytosol, which eventually contributed cell death. NIC also inhibited tumor weight and volume in the Ishikawa xenograft animal model without having any evidence of toxicity. Due to its potent anti-cancerous activity and safety profile, NIC seems to be a promising agent for human endometrial cancer therapeutics.

Mortalin is an essential chaperone for the import of nuclear‐encoded proteins into mitochondria and is elevated in ovarian cancer in association with poor patient prognosis. The investigational new drug, SHetA2, interacts with mortalin releasing its client proteins. In this study, interactions of SHetA2 moieties and mortalin substrate binding domain (SBD) amino acids are demonstrated by surface plasmon resonance (SPR) and nuclear magnetic resonance (NMR) to occur at low micromolar SHetA2 concentrations that selectively kill cancer cells over noncancerous cells. In both ovarian cancer and noncancerous cells SHetA2 reduces: mitochondria import of mortalin, degradation of mortalin's mitochondrial localization sequence (MLS), mortalin/inositol 1,4,5‐trisphosphate receptors complexes and oxidative phosphorylation. In cancer cells only, SHetA2 reduces calcium levels, mitochondrial length and fusion proteins, while inducing autophagy and PTEN‐induced kinase 1 (PINK1)/PARKIN‐mediated mitophagy. Noncancerous cells exhibit increased mitochondrial branch length in response to SHetA2 and a low level of inducible autophagy that is resistant to SHetA2. Inhibition of autophagosome‐lysosome fusion reduces, or increases, SHetA2 cytotoxicity in ovarian cancer or noncancerous cells, respectively. SHetA2 inhibits mortalin and growth, and induces mitophagy in ovarian cancer xenografts and increases survival post‐surgical tumor removal. In conclusion, SHetA2 binds directly to mortalin's SBD and causes distinct responses in ovarian cancer and noncancerous cells.