Expression of estrogen and progesterone receptors across human malignancies: new therapeutic opportunities

KRAS-Mutated, Estrogen Receptor-Positive Low-Grade Serous Ovarian Cancer: Unraveling an Exceptional Response Mystery

We report on a woman with aggressive estrogen receptor‐positive, KRAS‐mutated ovarian cancer who achieved a remarkable response to combination therapy with the MEK inhibitor (trametinib) and the aromatase inhibitor (letrozole), even though the disease had failed to respond to a combination of a PI3K inhibitor and different MEK inhibitor, as well as to trametinib and the estrogen modulator, tamoxifen, and to letrozole by itself. The mechanism of action for exceptional response was elucidated by in vitro experiments that demonstrated that the fact that tamoxifen can have an agonistic effect in addition to antagonist activity, whereas letrozole results only in estrogen depletion was crucial to the response achieved when letrozole was combined with an MEK inhibitor. Our current observations indicate that subtle variations in mechanisms of action of outwardly similar regimens may have a major impact on outcome and that such translational knowledge is critical for optimizing a precision medicine strategy.

Key Points

This report describes the remarkable response of a patient with KRAS‐mutated, estrogen receptor‐positive low‐grade serous ovarian cancer treated with trametinib (MEK inhibitor) and letrozole (aromatase inhibitor), despite prior progression on similar agents including tamoxifen (estrogen modulator).

In vitro investigation revealed that tamoxifen can have agonistic in addition to antagonistic effects, which could be the reason for the patient not responding to the combination of trametinib and tamoxifen.

The current observations suggest that drugs with different mechanisms of action targeting the same receptor may have markedly different anticancer activity when used in combinations.

This article reports the case of a patient with aggressive estrogen receptor‐positive, KRAS‐mutated ovarian cancer who achieved a remarkable response to combination therapy with the MEK inhibitor trametinib and the aromatase inhibitor letrozole, despite earlier failures of treatment with other combination inhibitor treatment. This article focuses on the possibility that subtle variations in mechanisms of action of outwardly similar regimens may have major effects on patient outcomes.

The emerging role of SPOP protein in tumorigenesis and cancer therapy

The nuclear speckle-type pox virus and zinc finger (POZ) protein (SPOP), a representative substrate-recognition subunit of the cullin-RING E3 ligase, has been characterized to play a dual role in tumorigenesis and cancer progression. Numerous studies have determined that SPOP suppresses tumorigenesis in a variety of human malignancies such as prostate, lung, colon, gastric, and liver cancers. However, several studies revealed that SPOP exhibited oncogenic function in kidney cancer, suggesting that SPOP could exert its biological function in a cancer type-specific manner. The role of SPOP in thyroid, cervical, ovarian, bone and neurologic cancers has yet to be determined. In this review article, we describe the structure and regulation of SPOP in human cancer. Moreover, we highlight the critical role of SPOP in tumorigenesis based on three major categories: physiological evidence (animal models), pathological evidence (human cancer specimens) and biochemical evidence (downstream ubiquitin substrates). Furthermore, we note that SPOP could be a promising therapeutic target for cancer treatment.

The emerging role of SPOP protein in tumorigenesis and cancer therapy

The nuclear speckle-type pox virus and zinc finger (POZ) protein (SPOP), a representative substrate-recognition subunit of the cullin-RING E3 ligase, has been characterized to play a dual role in tumorigenesis and cancer progression. Numerous studies have determined that SPOP suppresses tumorigenesis in a variety of human malignancies such as prostate, lung, colon, gastric, and liver cancers. However, several studies revealed that SPOP exhibited oncogenic function in kidney cancer, suggesting that SPOP could exert its biological function in a cancer type-specific manner. The role of SPOP in thyroid, cervical, ovarian, bone and neurologic cancers has yet to be determined. In this review article, we describe the structure and regulation of SPOP in human cancer. Moreover, we highlight the critical role of SPOP in tumorigenesis based on three major categories: physiological evidence (animal models), pathological evidence (human cancer specimens) and biochemical evidence (downstream ubiquitin substrates). Furthermore, we note that SPOP could be a promising therapeutic target for cancer treatment.

mPRα mediates P4/Org OD02-0 to improve the sensitivity of lung adenocarcinoma to EGFR-TKIs via the EGFR-SRC-ERK1/2 pathway

The discovery of epidermal growth factor receptor (EGFR) mutations has made EGFR tyrosine kinase inhibitors (EGFR-TKIs) a milestone in the treatment for advanced non-small cell lung cancer (NSCLC). However, patients lacking EGFR mutations are not sensitive to EGFR-TKI treatment and the emergence of secondary resistance poses new challenges for the targeted therapy of lung cancer. In this study, we identified that the expression of membrane progesterone receptor α (mPRα) was associated with EGFR mutations in lung adenocarcinoma patients and subsequently affected the efficacy of EGFR-TKIs. Progesterone (P4) or its derivative Org OD02-0 (Org), which is mediated by mPRα, increases the function of EGFR-TKIs to suppress the proliferation, migration, and invasion of lung adenocarcinoma cells in vitro and in vivo. In addition, the mPRα pathway triggers delayed resistance to EGFR-TKIs. Mechanistic investigations demonstrated that the mPRα pathway can crosstalk with the EGFR pathway by activating nongenomic effects to inhibit the EGFR-SRC-ERK1/2 pathway, thereby promoting antitumorigenic effects. In conclusion, our data describe an essential role for mPRα in improving sensitivity to EGFR-TKIs, thus rationalizing its potential as a therapeutic target for lung adenocarcinomas.

Gender-affirming hormone therapy and the risk of sex hormone-dependent tumours in transgender individuals-A systematic review

BACKGROUND

Cancers are a leading cause of death worldwide, and transgender individuals are no exception. The effects of gender-affirming hormone therapy (GAHT) on sex hormone-dependent tumours are unclear. Therefore, this review seeks to determine whether tumour risk in transgender individuals differs from the general population, to guide clinical screening recommendations.

METHODS

We performed a systematic review based on the PRISMA guidelines. MEDLINE, Embase and PsycINFO databases were searched for studies examining tumour incidence, prevalence or cancer-related mortality in transgender individuals. All English peer-reviewed publications were included if histological type and temporal relation to GAHT were reported. Case reports were included if there were ≥2 cases of the same histological type.

RESULTS

The search strategy identified 307 studies. Excluding those that did not meet inclusion criteria, 43 studies (7 cohort studies, 2 cross-sectional studies and 34 case reports) were reviewed. Retrospective cohort studies suggest no increase in risk of tumour development in transgender individuals receiving GAHT compared to the general population. Notably, the mean ages of cohorts were young and were treated with GAHT for insufficient durations to assess tumour risk. Case reports raise potential associations between high-dose oestradiol and anti-androgen therapy with prolactinoma and meningioma, respectively.

CONCLUSIONS

Further longitudinal studies are required to assess the risk of GAHT and hormone-dependent tumour development. Until further evidence is available, tumour screening should be based on guidelines for the general population and the presence of organs in transgender individuals rather than gender identity or hormonal therapy status.

Transcriptional profiling analysis of Zearalenone-induced inhibition proliferation on mouse thymic epithelial cell line 1

Zearalenone (ZEA) was a mycotoxin biosynthesized by a variety of Fusarium fungi via a polypeptide pathway. ZEA has significant toxic reaction on immune cells. Thymic epithelial cells (TECs) as a crucial constituent of thymic stroma can provide unique microenvironment for thymocyte maturation, but the mechanism of ZEA affecting the TECs is poorly understood. The basic data about gene expression differences for the ZEA on thymic epithelial cell line 1 (MTEC1) will help us to elucidate this mechanism. Here, cell viability and proliferation assay and transcriptome sequencing on MTEC1 treated with ZEA were performed. 4188 differentially expressed genes (DEGs) between ZEA treated and control groups were identified, confirmed and analyzed. Our results showed that 10-50μg/ml ZEA significantly inhibited MTEC1 proliferation and arrested cell cycle at G2/M phase. Gene ontology and KEGG pathway analysis revealed that Chemokine, JAK-STAT and Toll-like receptor signaling pathway, were involved in the cell cycle pathway. 16 key genes involved in the cell cycle processes were validated and the results suggested that Mitotic catastrophe (MC) may take part in ZEA inhibition of METC1 cell proliferation. These data highlighted the importance of cell cycle pathway in MTEC1 treated with ZEA, and will contribute to get the molecular mechanisms of ZEA inhibition of MTEC1 cell proliferation.

Assay of Calcium Transients and Synapses in Rat Hippocampal Neurons by Kinetic Image Cytometry and High-Content Analysis: An In Vitro Model System for Postchemotherapy Cognitive Impairment

Postchemotherapy cognitive impairment (PCCI) is commonly exhibited by cancer patients treated with a variety of chemotherapeutic agents, including the endocrine disruptor tamoxifen (TAM). The etiology of PCCI is poorly understood. Our goal was to develop high-throughput assay methods to test the effects of chemicals on neuronal function applicable to PCCI. Rat hippocampal neurons (RHNs) were plated in 96- or 384-well dishes and exposed to test compounds (forskolin [FSK], 17β-estradiol [ES]), TAM or fulvestrant [FUL], aka ICI 182,780) for 6-14 days. Kinetic Image Cytometry™ (KIC™) methods were developed to quantify spontaneously occurring intracellular calcium transients representing the activity of the neurons, and high-content analysis (HCA) methods were developed to quantify the expression, colocalization, and puncta formed by synaptic proteins (postsynaptic density protein-95 [PSD-95] and presynaptic protein Synapsin-1 [Syn-1]). As quantified by KIC, FSK increased the occurrence and synchronization of the calcium transients indicating stimulatory effects on RHN activity, whereas TAM had inhibitory effects. As quantified by HCA, FSK also increased PSD-95 puncta and PSD-95:Syn-1 colocalization, whereas ES increased the puncta of both PSD-95 and Syn-1 with little effect on colocalization. The estrogen receptor antagonist FUL also increased PSD-95 puncta. In contrast, TAM reduced Syn-1 and PSD-95:Syn-1 colocalization, consistent with its inhibitory effects on the calcium transients. Thus TAM reduced activity and synapse formation by the RHNs, which may relate to the ability of this agent to cause PCCI. The results illustrate that KIC and HCA can be used to quantify neurotoxic and neuroprotective effects of chemicals in RHNs to investigate mechanisms and potential therapeutics for PCCI.

MYCN-amplified neuroblastoma maintains an aggressive and undifferentiated phenotype by deregulation of estrogen and NGF signaling

High-risk neuroblastoma (NB), a cancer of the sympathetic nervous system, is challenging to treat. MYCN is frequently amplified in high-risk NB and is linked to an undifferentiated phenotype and poor prognosis. Estrogen and nerve growth factor (NGF) are inducers of neural differentiation, a process associated with a favorable disease. We show that MYCN suppresses estrogen receptor alpha (ERα) and thereby NGF signaling and neural differentiation. ERα overexpression is sufficient to interfere with different tumorigenic processes and tumor growth. In patients with NB, ERα expression correlates with several clinical markers for good prognosis. Importantly, not only ERα but also the majority of other nuclear hormone receptors are linked to favorable NB, suggesting a potential prognostic and therapeutic value for these proteins.

Neuroblastoma (NB) is a remarkably heterogenic childhood tumor of the sympathetic nervous system with clinical behavior ranging from spontaneous regression to poorly differentiated tumors and metastasis. MYCN is amplified in 20% of cases and correlates with an undifferentiated, aggressive phenotype and poor prognosis. Estrogen receptor alpha (ERα) and the nerve growth factor (NGF) receptors TrkA and p75^NTR are involved in neuronal differentiation and survival. We have previously shown that MYCN, via miR-18a, targets ERα in NB cells. Here, we demonstrate that interference with miR-18a or overexpression of ERα is sufficient to induce NGF signaling and to modulate both basal and NGF-induced neuronal differentiation in MYCN-amplified NB cells. Proteomic analysis confirmed an increase of neuronal features and showed that processes linked to tumor initiation and progression were inhibited upon ERα overexpression. Indeed, ectopic ERα expression was sufficient to inhibit metabolic activity and tumorigenic processes, including glycolysis, oxidative phosphorylation, cell viability, migration, and anchorage independent growth. Importantly, ERα overexpression reduced tumor burden in NB mouse models and high ERα levels were linked to improved survival in patients. In addition to ERα, several other nuclear hormone receptors (NHRs), including the glucocorticoid and the retinoic acid receptors, correlated with clinical markers for favorable and low-stage NB disease. Our data suggest that MYCN targets ERα and thereby NGF signaling to maintain an undifferentiated and aggressive phenotype. Notably, we identified the estrogen–NGF crosstalk, as well as a set of other NHRs, as potential prognostic markers and targets for therapeutic strategies against NB.

Sex disparity in cancer: roles of microRNAs and related functional players

A sexual dimorphism at the cellular level has been suggested to play a role in cancer onset and progression. In particular, very recent studies have unraveled striking differences between cells carrying XX or XY chromosomes in terms of response to stressful stimuli, indicating the presence of genetic and epigenetic differences determining sex-specific metabolic or phenotypic traits. Although this field of investigation is still in its infancy, available data suggest a key role of sexual chromosomes in determining cell life or death. In particular, cells carrying XX chromosomes exhibit a higher adaptive potential and survival behavior in response to microenvironmental variations with respect to XY cells. Cells from females also appear to be equipped with more efficient epigenetic machinery than the male counterpart. In particular, the X chromosome contains an unexpected high number of microRNAs (miRs), at present 118, in comparison with only two miRs localized on chromosome Y, and an average of 40-50 on the autosomes. The regulatory power of these small non-coding RNAs is well recognized, as 30-50% of all protein-coding genes are targeted by miRs and their role in cell fate has been well demonstrated. In addition, several further insights, including DNA methylation patterns that are different in males and females, claim for a significant gender disparity in cancer and in the immune system activity against tumors. In this brief paper, we analyze the state of the art of our knowledge on the implication of miRs encoded on sex chromosomes, and their related functional paths, in the regulation of cell homeostasis and depict possible perspectives for the epigenetic research in the field.

Cancer metastasis: enactment of the script for human reproductive drama

Based on compelling evidence from many biological disciplines, we put forth a hypothesis for cancer metastasis. In the hypothesis, the metastatic cascade is depicted as human reproduction in miniature. Illustrated in a reproductive light, the staggering resemblance of cancer metastasis to human reproduction becomes evident despite some ostensible dis-similarities. In parallel to the appearance of primordial germ cells during early embryogenesis, the cancer reproductive saga starts with the separation of metastasis initiating cells (MICs) from cancer initiating cells when the primary cancer is still in its infancy. Prime MICs embark on a journey to the host bone marrow where they undergo further development and regulation. Migrating MICs are guided by the same CXCR4/CYCL12 axis as used in the migration of primordial germ cells to the genital ridge. Like the ovary, the host bone marrow features immune privileges, coolness, hypoxia and acidity which are essential for stemness maintenance and regulation. Opportune activation of the MICs via fusion with bone marrow stem cells triggers a frenzy of cellular proliferation and sets them on the move again. This scenario is akin to oocyte fertilization in the Fallopian tube and its subsequent journey towards the decidum. Just as the human reproductive process is plagued with undesirable outcomes so is the cancer metastasis highly inefficient. The climax of the cancer metastatic drama (colonization) is reached when proliferating MIC clusters attempt to settle down on decidum-like premetastatic sites. Successfully colonized clusters blossom into overt macrometastases only after the execution of sophisticated immunomodulation, angiogenesis and vascular remodeling. Similarly, the implanted blastomere needs to orchestrate these feats before flourishing into a new life. What is more, the cancer reproductive drama seems to be directed by a primordial hypothalamus–pituitary–gonad axis. Pursuing this reproductive trail could lead to new frontiers and breakthroughs in cancer research and therapeutics.

Thymosin β4 Promotes Dermal Healing

No agent has been identified that significantly accelerates the repair of chronic dermal wounds in humans. Thymosin beta 4 (Tβ4) is a small, abundant, naturally occurring regenerative protein that is found in body fluids and inside cells. It was found to have angiogenic and antiinflammatory activity and to be high in platelets that aggregate at the wound site. Thus we used Tβ4 initially in dermal healing. It has since been shown to have many activities important in tissue protection, repair, and regeneration. Tβ4 increases the rate of dermal healing in various preclinical animal models, including diabetic and aged animals, and is active for burns as well. Tβ4 also accelerated the rate of repair in phase 2 trials with patients having pressure ulcers, stasis ulcers, and epidermolysis bullosa wounds. It is safe and well tolerated and will likely have additional uses in the skin and in injured organs for tissue repair and regeneration.