THYROID HORMONES AS A THIRD LINE OF AUGMENTATION MEDICATION IN TREATMENT-RESISTANT DEPRESSION

Introduction

Clinical or subclinical hypothyroidism dictates the severity of depressive episodes and more frequently overlaps psychotic phenomenology. There are also major depressive episodes resistant to treatment in patients with euthyroidism, in which supplementation of antidepressant medication with thyroid hormones is beneficial.

Material

Systematization of meta-analyses from perspectives: hypothyroidism and depression, autoimmune and depression pathology, gestational and puerperal pathology in association with hormonal and dispositional changes, presentation of therapeutic schemes.

Results

Hypothyroidism is more commonly comorbid with major depression in women. It associates the need for hospitalizations, psychotic phenomenology, resistance to treatment, somatic comorbidities. Autoimmune pathology is associated with depression and requires thorough investigation. A possible genetic candidate for thyroid dysfunction is the DIO1 gene. FT4 may be a predictor, but the combination of FT4 + TBG measured during the prenatal period has a higher prognostic power for a future depressive episode.

Conclusion

The article presents psychiatric medication schemes that combine antidepressants and antipsychotics of various classes with other enhancers, an important role going back to step three, which includes thyroid hormones, mainly T3. The doses used are smaller than the amount of endogenous production of T3 daily, with a small risk of inducing clinical hyperthyroidism.

The oleocanthal-based homovanillyl sinapate as a novel c-Met inhibitor

The hepatocyte growth factor (HGF)/mesenchymal-epithelial transition factor (c-Met) signaling axis has gained considerable attention as an attractive molecular target for therapeutic blockade of cancer. Inspired by the chemical structure of S (-)-oleocanthal, a natural secoiridoid from extra-virgin olive oil with documented anticancer activity against c-Met-dependent malignancies, the research presented herein reports on the discovery of the novel olive-derived homovanillyl sinapate (HVS) as a promising c-Met inhibitor. HVS was distinguished for its remarkable potency against wild-type c-Met and its oncogenic variant in cell-free assays and confirmed by in silico docking studies. Furthermore, HVS substantially impaired the c-Met-mediated growth across a broad spectrum of breast cancer cells, while similar treatment doses had no effect on the non-tumorigenic mammary epithelial cell growth. In addition, HVS caused a dose-dependent inhibition of HGF-induced, but not epidermal growth factor (EGF)-induced, cell scattering in addition to HGF-mediated migration, invasion, and 3-dimensional (3D) proliferation of tumor cell spheroids. HVS treatment effects were mediated via inhibition of ligand-mediated c-Met activation and its downstream mitogenic signaling and blocking molecular mediators involved in cellular motility across different cellular contexts. An interesting feature of HVS is its good selectivity for c-Met and Abelson murine leukemia viral oncogene homolog 1 (ABL1) when profiled against a panel of kinases. Docking studies revealed interactions likely to impart high dual affinity for both ABL1 and c-Met kinases. HVS markedly reduced tumor growth, showed excellent pharmacodynamics, and suppressed cell proliferation and microvessel density in an orthotopic model of triple negative breast cancer. Collectively, the present findings suggested that the oleocanthal-based HVS is a promising c-Met inhibitor lead entity with excellent therapeutic potential to control malignancies with aberrant c-Met activity.

Novel c-Met inhibitory olive secoiridoid semisynthetic analogs for the control of invasive breast cancer

Dysregulated receptor tyrosine kinase c-Met and its ligand HGF is valid and attractive molecular target for therapeutic blockade in cancer. Inspired by the chemical structure of the naturally occurring olive secoiridoid (-)-oleocanthal (1) and its documented anticancer activity against c-Met-dependent malignancies, a previous study reported tyrosol sinapate (4) as a c-Met inhibitor hit. This study reports additional semisynthetic optimization and SAR of 4 to improve its selective activity against c-Met-dependent breast cancer by increasing its capacity to inhibit c-Met phosphorylation. Forty-three compounds (5-47) were synthesized, among which the novel analog homovanillyl sinapate (HVS-16) was distinguished for its remarkable activity. HVS-16 substantially impaired c-Met-mediated proliferation, migration, and invasion across human breast cancer cell lines in two- and three-dimensional culture systems, while similar treatment doses were found to have effect neither on the non-tumorigenic human mammary epithelial cell growth nor on the c-Met independent breast cancer cell viability. HVS-16 showed a dose-dependent inhibition of ligand-mediated c-Met activation in human breast cancer cells. Docking studies revealed that HVS-16 fits very well inside c-Met crystal structures, satisfying critical interactions at the ATP binding site. This study identified important structural pharmacophoric features in HVS-16 and correlated its postulated binding pose with c-Met kinase assay data that would guide future olive secoiridoid bioisostere lead design. Results presented herein suggest HVS-16 as a promising c-Met inhibitor validated hit with potential to control invasive breast malignancies with aberrant c-Met activity.

Abstract 2869: FLASH-dependent post-translational regulation of the EMT activator ZEB1

Understanding the mechanisms of metastasis initiation and tumor persistence despite aggressive treatments is paramount to developing new viable therapeutic targets. Critical to tumor progression is initiation of epithelial-to-mesenchymal transition (EMT), a cellular process characterized by loss of E-cadherin, a critical cell-cell adhesion molecule, gain of migratory properties and chemoresistance. Transcriptional repression of E-cadherin and other genes responsible for maintaining the epithelial phenotype by ZEB1/ZEB2 family is one of the most significant events occurring at the interface between non-metastatic/metastatic cancer and chemo-sensitive/chemo-resistant cancer. Using a novel interdisciplinary high-throughput screen methodology we uncovered novel regulators of E-cadherin. Caspase 8 - associated protein 2 (CASP8AP2 or FLASH) a protein involved in apoptosis and transcriptional control was identified through this screen and we discovered that FLASH depletion resulted in increased E-cadherin levels at the plasma membrane through loss of ZEB1 expression. Subsequent examination of ZEB1 protein expression revealed that ZEB1 is rapidly degraded in FLASH-depleted cells. This process is blocked by proteasome inhibitors suggesting that post-translational modifications (PTMs) and in particular ubiquitination of ZEB1 is responsible for its fast turnover and decreased protein expression in the absence of FLASH. Indeed, ubiquitinated ZEB1 was detected in FLASH-depleted cells in the presence of proteasome inhibitors. Although ZEB1 is degraded through the ubiquitin pathway, its rapid turnover in the absence of FLASH suggests that protective mechanisms are in place to delay and/or prevent this process. Even more, we determined that the atypical ubiquitin E3 ligase complex Skp1-Pam-Fbxo45 is involved in ZEB1 degradation in the absence of FLASH and is upregulated in cells depleted for FLASH. Altogether our data suggests that FLASH can stabilizes ZEB1 indirectly by transcriptional repression of the ubiquitin ligase responsible for its degradation and directly by binding to ZEB1 and masking the recognition site of the ubiquitin ligase. Even more, absence of FLASH reprograms the cells into a more epithelial-like phenotype which is less invasive and is resistant to TGFβ-induced loss of E-cadherin. Not only is FLASH-dependent post-translational regulation of ZEB1 novel, but is also conserved in multiple cells lines from various tissues, making this mechanism an original therapeutic target for cancer metastasis.

Citation Format: Camille Abshire, Ana Maria Dragoi. FLASH-dependent post-translational regulation of the EMT activator ZEB1. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2869.

Signaling pathways leading to the activation of IKK and MAPK by thymosin alpha1

Thymosin alpha 1 (Talpha1) has therapeutic potential in the treatment of infectious diseases and cancer. However, the exact molecular pathways for Talpha1 action are not fully understood. We found that Talpha1 induces the production of interleukin-6 (IL-6), IL-10, and IL-12 in murine bone marrow-derived macrophages (BMDMs) through IKK and MAPK pathways. Talpha1 triggers the activation of AP-1 and the phosphorylation of JNK and p38. Inhibition of p38 impairs IL-6 production in response to Talpha1. Further, TRAF6 is involved in the activation of JNK and IRAK4 is involved for the activation of IKK and PKCzeta in a Talpha1-induced system. Loss of IRAK4 largely blocked induction of IL-6. Thus, our studies define early signal events that are critical for the Talpha1-induced immune responses.