Steroid hormones, steroid receptors, and breast cancer stem cells

Apolipoprotein A1-encoding recombinant adenovirus remodels cholesterol metabolism in tumors and the tumor microenvironment to inhibit hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a prevalent malignant tumor requiring effective treatments. Oncolytic viruses induce anti-tumor responses but have limited efficacy. Apolipoprotein A1 (ApoA1) inhibits inflammation, modulates immunity, and promotes anti-oxidation. This study aims to construct an oncolytic adenovirus (Ad5)-ApoA1 for superior anti-tumor effects. We analyzed ApoA1 expression in tumors and its prognostic significance using public databases. Subsequently, we engineered a recombinant oncolytic adenovirus Ad5-ApoA1 and assessed its replication and oncolytic efficacy in vitro and in nude mice. The impact of Ad5-ApoA1 on the tumor microenvironment of HCC was evaluated through flow cytometry, transcriptome sequencing, single-cell sequencing, and other methodologies. Additionally, mechanisms of immune microenvironment modulation by Ad5-ApoA1 were explored. ApoA1 expression was down-regulated with HCC progression and significantly positively correlated with the prognosis of HCC patients. Ad5-ApoA1 exhibited robust oncolytic activity but showed no therapeutic effect on nude mice. However, it significantly inhibited HCC growth and prolonged the survival period of both healthy-immune and humanized immune-reconstituted NCG mice. Furthermore, Ad5-ApoA1 significantly promoted the expression of IFN-γ and GzmB in CD8+ T cells while inhibiting the expression of PD-1 and LAG-3. Notably, the cholesterol content in the CD8+ T cells studied was significantly correlated with the expression of PD-1 and LAG-3, with ApoA1 promoting cholesterol efflux and reducing cholesterol levels. Ad5-ApoA1 activates CD8+ T cells by promoting large-scale viral replication. High levels of ApoA1 protein expression promote cholesterol efflux, inhibit CD8+ T cell depletion, and reduce inflammatory factors, ultimately leading to superior therapeutic effects on hepatocellular carcinoma.

Receptor tyrosine kinases and steroid hormone receptors in breast cancer: Review of recent evidences

Breast cancer development and progression are driven by intricate networks involving receptor tyrosine kinases (RTKs) and steroid hormone receptors specifically estrogen receptor (ER) and progesterone receptor (PR). This review examined roles of each receptor under normal physiology and in breast cancer, and explored their multifaceted interactions via signaling pathways, focusing on their contributions to breast cancer progression. Since defining the mechanism by which these two-receptor mediated signaling pathways cooperate is essential for understanding breast cancer progression, we discussed the mechanisms of cross-talk between RTKs and ER and PR and their potential therapeutic implications as well. The crosstalk between RTKs and steroid hormone receptors (ER and PR) in breast cancer can influence the disease's progression and treatment outcomes. Therefore, understanding the functions of the aforementioned receptors and their interactions is crucial for developing effective therapies.

Pyrimidine-triazole-tethered tert-butyl-piperazine-carboxylate suppresses breast cancer by targeting estrogen receptor signaling and β-catenin activation

Several chemotherapeutics against breast cancer are constrained by their adverse effects and chemoresistance. The development of novel chemotherapeutics to target metastatic breast cancer can bring effective clinical outcomes. Many breast cancer patients present with tumors that are positive for estrogen receptors (ERs), highlighting the importance of targeting the ER pathway in this particular subtype. Although selective estrogen receptor modulators (SERMs) are commonly used, their side effects and resistance issues necessitate the development of new ER-targeting agents. In this study, we report that a newly synthesized compound, TTP-5, a hybrid of pyrimidine, triazole, and tert-butyl-piperazine-carboxylate, effectively binds to estrogen receptor alpha (ERα) and suppresses breast cancer cell growth. We assessed the impact of TTP-5 on cell proliferation using MTT and colony formation assays and evaluated its effect on cell motility through wound healing and invasion assays. We further explored the mechanism of action of this novel compound by detecting protein expression changes using Western blotting. Molecular docking was used to confirm the interaction of TTP-5 with ERα. The results indicated that TTP-5 significantly reduced the proliferation of MCF-7 cells by blocking the ERα signaling pathway. Conversely, although it did not influence the growth of MDA-MB-231 cells, TTP-5 hindered their motility by modulating the expression of proteins associated with epithelial-mesenchymal transition (EMT), possibly via the Wnt/β-catenin pathway.

Multifunctional Nanomaterials Mediate Cholesterol Depletion for Cancer Treatment

Cholesterol is an essential membrane component, and the metabolites from cholesterol play important biological functions to intricately support cancer progression and dampen immune responses. Preclinical and clinical studies have demonstrated the role of cholesterol metabolism regulation on inhibiting tumor growth, remodeling the immunosuppressive tumor microenvironment (TME), and enhancing anti-tumor immunity. In this minireview, we discuss complex cholesterol metabolism in tumors, its important role in cancer progression, and its influences on immune cells in the TME. We provide an overview of recent advances in cancer treatment through regulating cholesterol metabolism. We discuss the design of cholesterol-altering multifunctional nanomaterials to regulate oxidative stress, modulate immune checkpoints, manipulate mechanical stress responses, and alter cholesterol metabolic pathways. Additionally, we examine the interactions between cholesterol metabolism regulation and established cancer treatments with the aim of identifying efficient strategies to disrupt cholesterol metabolism and synergistic combination therapies for effective cancer treatment.

A rapid quantitative UPLC-MS/MS method for analysis of key regulatory oxysterols in biological samples for liver cancer

An UPLC-APCI-MS/MS method was developed for the simultaneous determination of cholesterol, 7-dehydrocholesterol (7DHC) and eight oxysterols including 27-hydroxycholesterol (27OHC), 7α-hydroxycholesterol (7αOHC), 7β-hydroxycholesterol (7βOHC), 24S-hydroxycholesterol (24SOHC), 25-hydroxycholesterol (25OHC), 7α,24S-dihydroxycholesterol (7α,24SdiOHC), 7α,25-dihydroxycholesterol (7α,25diOHC), and 7α,27-dihydroxycholesterol (7α,27diOHC). It has been used for quantitative analysis of cholesterol, 7DHC and eight oxysterols in hepatocellular carcinoma (HCC) cells, plasma and tumor tissue samples. And the above compounds were extracted from the biological matrix (plasma and tissue) using liquid-liquid extraction with hexane/isopropanol after saponification to cleave the steroids from their esterified forms without further derivatization. Then cholesterol, 7DHC and oxysterols were separated on a reversed phase column (Agilent Zorbax Eclipse plus, C18) within 8 min using a gradient elution with 0.1 % formic acid in H2O and methanol and detected by an APCI triple quadrupole mass spectrometer. The lower limit of quantification (LLOQ) of the cholesterol, 7DHC and oxysterols ranged from 3.9 ng/mL to 31.25 ng/mL, and the recoveries ranged from 83.0 % to 113.9 %. Cholesterol, 7DHC and several oxysterols including 27OHC, 7αOHC and 7βOHC were successfully quantified in HCC cells, plasma, tissues and urine of HCC mice. Results showed that 27OHC was at high levels in three kind of HCC cells and tumor tissues as well as plasma samples from both HepG2 and Huh7 bearing mice model，and the high levels of 27OHC in tumors were associated with HCC development. Moreover, the levels of cholesterol in HCC cells and tumor issues varied in different HCC cells and mice model. Oxysterols profiling in biological samples might provide complementary information in cancer diagnosis.

Valsartan as a prophylactic treatment against breast cancer development and niche activation: What molecular sequels follow chronic AT-1R blockade?

AIMS

Transactivation of insulin-growth-factor-receptor (IGF-1R) by angiotensin-II-type-1-receptor (AT-1R) was only demonstrated in vascular-smooth-muscle cells and has never been tested in breast-cancer (BC). This investigation addressed the impact of chronic AT-1R blockade by valsartan (Val) on possible concurrent AT-1R/IGF-1R signaling inhibition, regressing BC-tumor-microenvironment (TME) cellular components activation, and hindering BC development.

MAIN METHODS

The effect of different Val doses (10, 20, 40 & 80 mg/kg/day for 490 days) was tested on dimethylbenz(a)anthracene (DMBA)-induced progesterone-promoted-BC in rats. The influence on intratumoral/circulating angiotensin-II (ANG-II) levels and AT-1R/Mas-R immunofluorescent-expression were assessed. The potential AT-1R/IGF-1R crosstalk within TME-BC-stem-cells (BCSCs) and cancer-associated-fibroblasts (CAFs) was evaluated by fluorescently marking these cells and locating the immunofluorescently-stained AT-1R/IGF-1R in them using confocal-laser-microscopy and further quantified by flow cytometry. In addition, the molecular alterations following blocking AT-1R were inspected including determining Src; crucial for IGF-1R transactivation by AT-1R, Notch-1; IGF-IR transcriptional-regulator, and PI3K/Akt &IL-6/STAT expression. Further, the suppression of CSCs' capabilities to maintain pluripotency, stemness features, epithelial-to-mesenchymal-transition (EMT), and angiogenesis was evaluated by assessing NANOG gene, aldehyde-dehydrogenase (ALDH), N-cadherin and vascular-endothelial-growth-factor (VEGF), respectively. Furthermore, the proliferative marker; Ki-67, was detected by immunostaining, and tumors were histologically graded using Elston-Ellis-modified-Scarff-Bloom-Richardson method.

KEY FINDINGS

Prophylactic Val significantly reduced tumor size, prolonged latency, reduced tumor histopathologic grade, decreased circulating/intratumoral-ANG-II levels, increased Mas-R, and decreased AT1R expression. AT-1R/IGF-1R were co-expressed with a high correlation coefficient on CAFs/BCSCs. Moreover, Val significantly attenuated IGF-1R transactivation and transcriptional regulation via Src and Notch-1 genes' downregulation and reduced Src/IGF-IR-associated PI3K/Akt and IL-6/STAT3 signaling. Further, Val significantly decreased intratumoral NANOG, ALDH, N-cadherin, VEGF, and Ki-67 levels.

SIGNIFICANCE

Chronic Val administration carries a potential for repurposing as adjuvant or conjunct therapy for patients at high risk for BC.

Progesterone modulates cell growth via integrin αvβ3-dependent pathway in progesterone receptor-negative MDA-MB-231 cells

Progesterone (P4) plays a pivotal role in regulating the cancer progression of various types, including breast cancer, primarily through its interaction with the P4 receptor (PR). In PR-negative breast cancer cells, P4 appears to function in mediating cancer progression, such as cell growth. However, the mechanisms underlying the roles of P4 in PR-negative breast cancer cells remain incompletely understood. This study aimed to investigate the effects of P4 on cell proliferation, gene expression, and signal transduction in PR-negative MDA-MB-231 breast cancer cells. P4-activated genes, associated with proliferation in breast cancer cells, exhibit a stimulating effect on cell growth in PR-negative MDA-MB-231 cells, while demonstrating an inhibitory impact in PR-positive MCF-7 cells. The use of arginine-glycine-aspartate (RGD) peptide successfully blocked P4-induced extracellular signal-regulated kinase 1/2 (ERK1/2) activation, aligning with computational models of P4 binding to integrin αvβ3. Disrupting integrin αvβ3 binding with RGD peptide or anti-integrin αvβ3 antibody altered P4-induced expression of proliferative genes and modified P4-induced cell growth in breast cancer cells. In conclusion, integrin αvβ3 appears to mediate P4-induced ERK1/2 signal pathway to regulate proliferation via alteration of proliferation-related gene expression in PR-negative breast cancer cells.

Unnatural Peptide Assemblies Rapidly Deplete Cholesterol and Potently Inhibit Cancer Cells

Cholesterol-rich membranes play a pivotal role in cancer initiation and progression, necessitating innovative approaches to target these membranes for cancer inhibition. Here we report the first case of unnatural peptide (1) assemblies capable of depleting cholesterol and inhibiting cancer cells. Peptide 1 self-assembles into micelles and is rapidly taken up by cancer cells, especially when combined with an acute cholesterol-depleting agent (MβCD). Click chemistry has confirmed that 1 depletes cell membrane cholesterol. It localizes in membrane-rich organelles, including the endoplasmic reticulum, Golgi apparatus, and lysosomes. Furthermore, 1 potently inhibits malignant cancer cells, working synergistically with cholesterol-lowering agents. Control experiments have confirmed that C-terminal capping and unnatural amino acid residues (i.e., BiP) are essential for both cholesterol depletion and potent cancer cell inhibition. This work highlights unnatural peptide assemblies as a promising platform for targeting the cell membrane in controlling cell fates.

Connecting the mechanisms of tumor sex differences with cancer therapy

Sex differences in cancer incidence and survival are constant and pronounced globally, across all races and all age groups of cancer types. In 2016, after the National Institutes of Health proposed a policy of utilizing sex as a biological variable, researchers started paying more attention to the molecular mechanisms behind gender variations in cancer. Historically, most previous studies investigating sex differences have been centered on gonadal sex hormones. Nevertheless, sex differences also involve genetic and molecular pathways that run throughout the entire process of cancer cell proliferation, metastasis, and treatment response, in addition to sex hormones. In particular, there is significant gender dimorphism in the efficacy and toxicity of oncology treatments, including conventional radiotherapy and chemotherapy, as well as the emerging targeted therapies and immunotherapy. To be clear, not all mechanisms will exhibit gender bias, and not all gender bias will affect cancer risk. Our goal in this review is to discuss some of the significant sex-related changes in fundamental cancer pathways. To this purpose, we summarize the differential impact of gender on cancer development in three dimensions: sex hormones, genetics, and epigenetics, and focus on current hot subjects including tumor suppressor function, immunology, stem cell renewal, and non-coding RNAs. Clarifying the essential mechanisms of gender differences will help guide the clinical treatment of both sexes in tumor radiation and chemotherapy, medication therapy with various targets, immunotherapy, and even drug development. We anticipate that sex-differentiated research will help advance sex-based cancer personalized medicine models and encourage future basic scientific and clinical research to take sex into account.

Hormonal and natural contraceptives: a review on efficacy and risks of different methods for an informed choice

The debate about contraception has become increasingly important as more and more people seek safe and effective contraception. More than 1 billion women of reproductive age worldwide need a method of family planning, and wellbeing, socio-economic status, culture, religion and more influence the reasons why a woman may ask for contraception. Different contraceptive methods exist, ranging from 'natural methods' (fertility awareness-based methods - FABMs) to barrier methods and hormonal contraceptives (HCs). Each method works on a different principle, with different effectiveness.FABMs and HCs are usually pitted against each other, although it's difficult to really compare them. FABMs are a valid alternative for women who cannot or do not want to use hormone therapy, although they may have a high failure rate if not used appropriately and require specific training. HCs are commonly used to address various clinical situations, although concerns about their possible side effects are still widespread. However, many data show that the appropriate use of HC has a low rate of adverse events, mainly related to personal predisposition.The aim of this review is to summarize the information on the efficacy and safety of FABMs and HCs to help clinicians and women choose the best contraceptive method for their needs.

Recent advancements in nanomedicine based lipid metabolism for tumour immunotherapy

Therapy on lipid metabolism is emerging as a groundbreaking cancer treatment, offering the unprecedented opportunity to effectively treat and in several cases. Tumorigenesis is inextricably linked to lipid metabolism. In this regard, the features of lipid metabolism include lipid synthesis, decomposition, metabolism and lipid storage and mobilisation from intracellular lipid droplets. Most importantly, the regulation of lipid metabolism is central to the appropriate immune response of tumour cells, and ultimately to exert the immune efforts to realise the perspective of many anti-tumour effects. Different cancers and immune cells have different dependence on lipid metabolism, playing a pivotal role in differentiation and function of immune cells. However, what lies before the immunotherapy targeting lipid metabolism is side effects of systemic toxicity and defects of individual drugs, which strongly highlights that nanodelivery strategy is a magnet for it to enhance drug efficiency, reduce drug toxicity and improve application deficiencies. This review will first focus on emerging research progress of lipid metabolic reprogramming mechanism, and then explore the complex role of lipid metabolism in the tumour cells including the effect on immune cells and their nano-preparations of monotherapy and multiple therapies used in combination, in a shift away from conventional cancer research.HighlightsThe regulation of lipid metabolism is central to the appropriate immune response of tumour cells, and ultimately to exert the immune efforts to realise the perspective of many anti-tumour effects.Preparations of focusing lipid metabolism have side effects of systemic toxicity and defects of individual drugs. It strongly highlights that nanodelivery strategy is a magnet for it to enhance drug efficiency, reduce drug toxicity and improve application deficiencies.This review will first focus on emerging research progress of lipid metabolic reprogramming mechanism, and then explore the complex role of lipid metabolism in the tumour cells including the effect on immune cells as well as their nano-preparations of monotherapy and multiple therapies used in combination, in a shift away from conventional cancer research.

Dysregulation of cholesterol metabolism in cancer progression

Cholesterol homeostasis has been implicated in the regulation of cellular and body metabolism. Hence, deregulated cholesterol homeostasis leads to the development of many diseases such as cardiovascular diseases, and neurodegenerative diseases, among others. Recent studies have unveiled the connection between abnormal cholesterol metabolism and cancer development. Cholesterol homeostasis at the cellular level dynamically circulates between synthesis, influx, efflux, and esterification. Any dysregulation of this dynamic process disrupts cholesterol homeostasis and its derivatives, which potentially contributes to tumor progression. There is also evidence that cancer-related signals, which promote malignant progression, also regulate cholesterol metabolism. Here, we described the relationship between cholesterol metabolism and cancer hallmarks, with particular focus on the molecular mechanisms, and the anticancer drugs that target cholesterol metabolism.

Molecular characterization of breast cancer cell pools with normal or reduced ability to respond to progesterone: a study based on RNA-seq

BACKGROUND

About one-third of patients with estrogen receptor alpha (ERα)-positive breast cancer have tumors which are progesterone receptor (PR) negative. PR is an important prognostic factor in breast cancer. Patients with ERα-positive/PR-negative tumors have shorter disease-free and overall survival than patients with ERα-positive/PR-positive tumors. New evidence has shown that progesterone (P4) has an anti-proliferative effect in ERα-positive breast cancer cells. However, the role of PR in breast cancer is only poorly understood.

METHODS

We disrupted the PR gene (PGR) in ERα-positive/PR-positive T-47D cells using the CRISPR/Cas9 system. This resulted in cell pools we termed PR-low as P4 mediated effects were inhibited or blocked compared to control T-47D cells. We analyzed the gene expression profiles of PR-low and control T-47D cells in the absence of hormone and upon treatment with P4 alone or P4 together with estradiol (E2). Differentially expressed (DE) genes between experimental groups were characterized based on RNA-seq and Gene Ontology (GO) enrichment analyses.

RESULTS

The overall gene expression pattern was very similar between untreated PR-low and untreated control T-47D cells. More than 6000 genes were DE in control T-47D cells upon stimulation with P4 or P4 plus E2. When PR-low pools were subjected to the same hormonal treatment, up- or downregulation was either blocked/absent or consistently lower. We identified more than 3000 genes that were DE between hormone-treated PR-low and control T-47D cells. GO analysis revealed seven significantly enriched biological processes affected by PR and associated with G protein-coupled receptor (GPCR) pathways which have been described to support growth, invasiveness, and metastasis in breast cancer cells.

CONCLUSIONS

The present study provides new insights into the complex role of PR in ERα-positive/PR-positive breast cancer cells. Many of the genes affected by PR are part of central biological processes of tumorigenesis.

Effect of proprotein convertase subtilisin/kexin type 9 inhibition on cancer events: A pooled, post hoc, competing risk analysis of alirocumab clinical trials

OBJECTIVE

Assess the risk of new and worsening cancer events among participants who received the lipid-lowering therapy alirocumab, a proprotein convertase subtilisin/kexin type 9 inhibitor.

DESIGN

Pooled post hoc analysis.

SETTING

Six phase 3 or phase 4 placebo-controlled randomised trials with alirocumab.

PARTICIPANTS

A total of 24,070 patients from the safety population with complete dosing data (alirocumab, n = 12,533; placebo, n = 11,537).

INTERVENTION

Alirocumab 75 mg, alirocumab 150 mg, alirocumab 75 mg increasing to 150 mg if low-density lipoprotein cholesterol <50 mg/dL not achieved, or placebo, all every 2 weeks. All participants received background high-intensity or maximum-tolerated statin therapy.

OUTCOMES AND MEASURES

The first new or worsening incident cancer events were assessed during the treatment-emergent adverse event period. Four outcomes were evaluated: any-neoplasm, malignant neoplasms, broad definition of hormone-sensitive cancers, and stricter definition of hormone-sensitive cancers. Sub-distribution hazard ratios and 95% confidence intervals (CIs) were estimated using a competing risk framework, with death as a competing risk.

RESULTS

Considering both treatment arms in aggregate, 969 (4.03%), 779 (3.24%), 178 (0.74%) and 167 (0.69%) patients developed any neoplasm, malignant neoplasms, broad definition of hormone-sensitive cancer and strict definition of hormone-sensitive cancer events, respectively. There was no significant difference in the risk of having any neoplasm in the alirocumab versus the placebo group (sub-distribution hazards ratio [95% CI], 0.93 [0.82-1.1]; p = 0.28). A nominally lower risk of having any neoplasms with alirocumab was observed among subjects aged ≥64 years (sub-distribution hazards ratio 0.83; 95% CI, 0.70-0.99).

CONCLUSIONS

Intensive low-density lipoprotein cholesterol lowering with a proprotein convertase subtilisin/kexin type 9 inhibitor combined with statin does not appear to increase the risk of new or worsening cancer events.

Comprehensive analysis of the clinical and biological significances of cholesterol metabolism in lower-grade gliomas

BACKGROUND

As a component of membrane lipids and the precursor of oxysterols and steroid hormones, reprogrammed cholesterol metabolism contributes to the initiation and progression of multiple cancers. Thus, we aim to further investigate the significances of cholesterol metabolism in lower-grade gliomas (LGGs).

METHODS

The present study included 413 LGG samples from TCGA RNA-seq dataset (training cohort) and 172 LGG samples from CGGA RNA-seq dataset (validation cohort). The cholesterol metabolism-related signature was identified by the LASSO regression model. Bioinformatics analyses were performed to explore the functional roles of this signature in LGGs. Kaplan-Meier and Cox regression analyses were enrolled to estimate prognostic value of the risk signature.

RESULTS

Our findings suggested that cholesterol metabolism was tightly associated clinicopathologic features and genomic alterations of LGGs. Bioinformatics analyses revealed that cholesterol metabolism played a key role in immunosuppression of LGGs, mainly by promoting macrophages polarization and T cell exhaustion. Kaplan-Meier curve and Cox regression analysis showed that cholesterol metabolism was an independent prognostic indicator for LGG patients. To improve the clinical application value of the risk signature, we also constructed a nomogram model to predict the 1-, 3- and 5-year survival of LGG patients.

CONCLUSION

The cholesterol metabolism was powerful prognostic indicator and could serve as a promising target to enhance personalized treatment of LGGs.

New insights into the therapeutic potentials of statins in cancer

The widespread clinical use of statins has contributed to significant reductions of cardiovascular morbidity and mortality. Increasing preclinical and epidemiological evidences have revealed that dyslipidemia is an important risk factor for carcinogenesis, invasion and metastasis, and that statins as powerful inhibitor of HMG-CoA reductase can exert prevention and intervention effects on cancers, and promote sensitivity to anti-cancer drugs. The anti-cancer mechanisms of statins include not only inhibition of cholesterol biosynthesis, but also their pleiotropic effects in modulating angiogenesis, apoptosis, autophagy, tumor metastasis, and tumor microenvironment. Moreover, recent clinical studies have provided growing insights into the therapeutic potentials of statins and the feasibility of combining statins with other anti-cancer agents. Here, we provide an updated review on the application potential of statins in cancer prevention and treatment and summarize the underneath mechanisms, with focuses on data from clinical studies.

Cancer-biomarkers associated with sex hormone receptors and recent therapeutic advancements: a comprehensive review

Hormones and its regulation plays vital role in causing breast, prostate, ovarian and endometrial cancers collectively known as hormone-sensitive cancers. This review discusses the various functions of the sex hormones and the biological pathways involved in causing hormone-associated cancer under differential regulation. We have also attempted to explore the biomarkers associated with the cancers and the current therapeutic availability to treat such cancers. Among various sex hormones such as estrogen, progesterone and androgen, estrogen the female sex hormone and its receptor had a major contribution in causing cancer and hence are considered a predominant target in treating the associated cancers. Other hormones and receptors such a androgen, progesterone, and their respective receptors were also reported to have a significant correlation in causing cancers. Apart from these receptors certain enzymes that act as precursors or as promoters are also targeted for treatment strategies. The drugs commonly used belong to the selective drug classes such as selective estrogen receptor modulators and selective progesterone receptor modulators. In the case of androgen regulation androgen deprivation therapies are practiced. It is also suggested that the use of natural substances to treat cancer could prevent resistance and reduce side effects. Identification of significant targets and the discovery of many efficient drugs shall be possible in the future with better understanding of hormone regulation and its influence on cancer causative mechanisms.

Phase 1 study of oral selective estrogen receptor degrader (SERD) amcenestrant (SAR439859), in Japanese women with ER-positive and HER2-negative advanced breast cancer (AMEERA-2)

BACKGROUND

This AMEERA-2 study evaluated the pharmacokinetics, efficacy, and safety of the oral selective estrogen receptor degrader amcenestrant as a monotherapy with dose escalation in Japanese postmenopausal women with advanced estrogen receptor-positive and human epidermal growth factor receptor 2-negative breast cancer.

METHODS

In this open-label, nonrandomized, phase I study, patients received amcenestrant 400 mg once daily (QD) (n = 7) and 300 mg twice daily (BID) (n = 3). The incidence of dose-limiting toxicities (DLT), recommended dose, maximum tolerated dose (MTD), pharmacokinetics, efficacy, and safety were assessed.

RESULTS

No DLTs were observed and MTD was not reached in the 400 mg QD group. One DLT (grade 3 maculopapular rash) was reported in a patient treated with 300 mg BID. After repeated oral administration of either dosing regimen, steady state reached before day 8, without accumulation. Four out of 5 response-evaluable patients from 400 mg QD group achieved clinical benefit and showed tumor shrinkage. No clinical benefit was reported in the 300 mg BID group. Overall, most patients (8/10) experienced a treatment-related adverse event (TRAE), with skin and subcutaneous tissue disorders most commonly reported (4/10 patients). No ≥ grade 3 TRAE in 400 mg QD group and 1 grade 3 TRAE in 300 mg BID group were reported.

CONCLUSIONS

Amcenestrant 400 mg QD has a favorable safety profile and has been selected as the recommended Phase II dose for monotherapy for evaluating the safety and efficacy of amcenestrant in a larger, global, randomized clinical trial of patients with metastatic breast cancer.

TRIAL REGISTRATION

Clinical trial registration NCT03816839.

Codon adaptation by synonymous mutations impacts the functional properties of the estrogen receptor-alpha protein in breast cancer cells

Oestrogen receptor-alpha (ERα) positivity is intimately associated with the development of hormone-dependent breast cancers. A major challenge in the treatment of these cancers is to understand and overcome the mechanisms of endocrine resistance. Recently, two distinct translation programmes using specific transfer RNA (tRNA) repertoires and codon usage frequencies were evidenced during cell proliferation and differentiation. Considering the phenotype switch of cancer cells to more proliferating and less-differentiated states, we can speculate that the changes in the tRNA pool and codon usage that likely occur make the ERα coding sequence no longer adapted, impacting translational rate, co-translational folding and the resulting functional properties of the protein. To verify this hypothesis, we generated an ERα synonymous coding sequence whose codon usage was optimized to the frequencies observed in genes expressed specifically in proliferating cells and then investigated the functional properties of the encoded receptor. We demonstrate that such a codon adaptation restores ERα activities to levels observed in differentiated cells, including: (a) an enhanced contribution exerted by transactivation function 1 (AF1) in ERα transcriptional activity; (b) enhanced interactions with nuclear receptor corepressor 1 and 2 [NCoR1 and NCoR2 (also known as SMRT) respectively], promoting repressive capability; and (c) reduced interactions with SRC proto-oncogene, non-receptor tyrosine kinase (Src) and phosphoinositide 3-kinase (PI3K) p85 kinases, inhibiting MAPK and AKT signalling pathway.

Vasopressin induces apoptosis but does not enhance the antiproliferative effect of dynamin 2 or PI3K/Akt inhibition in luminal A breast cancer cells

Breast cancer cells abnormally express vasopressin (AVP) and its receptors. The effect of AVP is largely orchestrated through its downstream signaling and by receptor-mediated endocytosis (RME), in which Dynamin 2 (Dyn2) plays an integral role in vesicle closure. In this work, luminal A breast cancer cells were treated with AVP, and then Dynasore (DYN) was employed to inhibit Dyn2 to explore the combined effect of AVP and Dyn2 inhibition on the survival of breast cancer cells. The results revealed that DYN alone demonstrated a concentration-dependent cytotoxic effect in AVP untreated cells. Apoptosis developed in 29.7 and 30.3% of cells treated with AVP or AVP+DYN, respectively, compared to 32.5% in cells treated with Wortmannin (Wort, a selective PI3K pathway inhibitor). More apoptosis was observed when cells were treated with DYN+Wort in presence or absence of exogenous AVP. Besides, 2 or 4- fold increases in the expression of Bax and Caspase-3, were observed in cells exposed to AVP in absence or presence of DYN, respectively. This was associated with higher levels of the autophagy marker (LC3II protein). Meanwhile, the activation of Akt protein, sequentially decreased in the same pattern. Cell's invasion decreased when they were exposed to AVP alone or combined with DYN or/and Wort. Conclusively, although many reports suggested the proliferative effect of AVP, the results predict the antiproliferative and antimetastatic effects of 100 nM AVP in luminal A breast cancer cells. However, the hormone did not enhance the cytotoxic effect of Dyn 2 or PI3K pathway inhibition. Summary of the Dynamin 2 independent AVP antiproliferative effects. Breast cancer cells expresses AVP as a Prohormone (A). At high dose of AVP, the hormone is liganded with AVP receptor (B) to initiate RME, where the endosomed complex (C) is degraded through the endosome-lysosome system, as a part of signal management. These events consume soluble Dyn2 in neck closure and vesicle fission (D). This makes the cells more substitutable to the direct apoptotic effect of DYN (E). Alternatively, at lower AVP doses the liganded AVP may initiate cAMP-mediated downstream signaling (F) and cellular proliferation. In parallel, Wort inhibits PIP2-PIP3 conversion (G) and the subsequent inhibition of PI3K/Akt/mTOR pathway leading to cell death.

Serum cholesterol and the risk of developing hormonally driven cancers: A narrative review

Although cholesterol has been hypothesized to promote cancer development through several potential pathways, its role in the risk of developing hormonally driven cancer is controversial. This literature review summarizes evidence from the highest quality studies to examine the consistency and strength of the relationship between serum cholesterol parameters and incidence of hormonally driven cancer. Articles were identified using EMBASE. Longitudinal observational studies published between January 2000 and December 2020 were considered for inclusion. The endpoint of interest was incident prostate, ovary, breast, endometrium, and uterine cancers. In total, 2732 reports were identified and screened; 41 studies were included in the review. No associations were found for ovarian cancer. Most endometrial cancer studies were null. The majority (76.9%) of studies reported no association between cholesterol and prostate cancer. Data on breast cancer were conflicting, associations limited, and effect sizes modest. Our results do not provide evidence for a clear association between cholesterol and different types of incident, hormonally driven reproductive cancers. Future studies should investigate the impact of lipid-lowering therapy.

ERα-LBD, an isoform of estrogen receptor alpha, promotes breast cancer proliferation and endocrine resistance

Estrogen receptor alpha (ERα) drives mammary gland development and breast cancer (BC) growth through an evolutionarily conserved linkage of DNA binding and hormone activation functions. Therapeutic targeting of the hormone binding pocket is a widely utilized and successful strategy for breast cancer prevention and treatment. However, resistance to this endocrine therapy is frequently encountered and may occur through bypass or reactivation of ER-regulated transcriptional programs. We now identify the induction of an ERα isoform, ERα-LBD, that is encoded by an alternative ESR1 transcript and lacks the activation function and DNA binding domains. Despite lacking the transcriptional activity, ERα-LBD is found to promote breast cancer growth and resistance to the ERα antagonist fulvestrant. ERα-LBD is predominantly localized to the cytoplasm and mitochondria of BC cells and leads to enhanced glycolysis, respiration and stem-like features. Intriguingly, ERα-LBD expression and function does not appear to be restricted to cancers that express full length ERα but also promotes growth of triple-negative breast cancers and ERα-LBD transcript (ESR1-LBD) is also present in BC samples from both ERα(+) and ERα(-) human tumors. These findings point to ERα-LBD as a potential mediator of breast cancer progression and therapy resistance.

The relationship between using estrogen and/or progesterone and the risk of mammary gland hyperplasia in women: a meta-analysis

BACKGROUND

As reported that the usage of estrogen and/or progesterone increases the risk of mammary gland hyperplasia (MGH) with conflicting results. Therefore, we conducted a meta-analysis to higher elucidate the relationship between hormones and MGH.

METHOD

PubMed, Embase, Web of Science, Cochrane Library, Chinese National Knowledge Infrastructure, and Wan-fang database were searched for studies until April 28, 2021.

RESULTS

Nine related studies were included in the present meta-analysis. We found that the usage of estrogen and/or progesterone had a significant association with increasing the risk of MGH (RR = 1.56, 95% CI: 1.13-2.15, p = .000). The subgroup results showed that the risk of MGH increased in the Mix population (RR = 1.72, CI: 1.58-1.88, p < .001) but no significant difference in the Asian population. Meanwhile, as for using estrogen plus progesterone (EPP) and postmenopausal women the risk of MGH, respectively, increased (RR = 1.74, CI: 1.22-2.47, p = .002) and (RR = 1.75, CI: 1.24-2.47, p = .001) but no significant different for using estrogen alone and premenopausal women.

CONCLUSIONS

This study findings indicated that using estrogen and/or progesterone might increase the risk of MGH in premenopausal and postmenopausal women.

Cholesterol and Its Derivatives: Multifaceted Players in Breast Cancer Progression

Cholesterol is an essential lipid primarily synthesized in the liver through the mevalonate pathway. Besides being a precursor of steroid hormones, bile acid, and vitamin D, it is an essential structural component of cell membranes, is enriched in membrane lipid rafts, and plays a key role in intracellular signal transduction. The lipid homeostasis is finely regulated end appears to be impaired in several types of tumors, including breast cancer. In this review, we will analyse the multifaceted roles of cholesterol and its derivatives in breast cancer progression. As an example of the bivalent role of cholesterol in the cell membrane of cancer cells, on the one hand, it reduces membrane fluidity, which has been associated with a more aggressive tumor phenotype in terms of cell motility and migration, leading to metastasis formation. On the other hand, it makes the membrane less permeable to small water-soluble molecules that would otherwise freely cross, resulting in a loss of chemotherapeutics permeability. Regarding cholesterol derivatives, a lower vitamin D is associated with an increased risk of breast cancer, while steroid hormones, coupled with the overexpression of their receptors, play a crucial role in breast cancer progression. Despite the role of cholesterol and derivatives molecules in breast cancer development is still controversial, the use of cholesterol targeting drugs like statins and zoledronic acid appears as a challenging promising tool for breast cancer treatment.

New Clues to Prognostic Biomarkers of Four Hematological Malignancies

Globally, one out of every two reported cases of hematologic malignancies (HMs) results in death. Each year approximately 1.24 million cases of HMs are recorded, of which 58% become fatal. Early detection remains critical in the management and treatment of HMs. However, this is thwarted by the inadequate number of reliable biomarkers. In this study, we mined public databases for RNA-seq data on four common HMs intending to identify novel biomarkers that could serve as HM management and treatment targets. A standard RNA-seq analysis pipeline was strictly adhered to in identifying differentially expressed genes (DEGs) with DESeq2, limma+voom and edgeR. We further performed gene enrichment analysis, protein-protein interaction (PPI) network analysis, survival analysis and tumor immune infiltration level detection on the genes using G:Profiler, Cytoscape and STRING, GEPIA tool and TIMER, respectively. A total of 2,136 highly-ranked DEGs were identified in HM vs. non-HM samples. Gene ontology and pathway enrichment analyses revealed the DEGs to be mainly enriched in steroid biosynthesis (5.075×10-4), cholesterol biosynthesis (2.525×10-8), protein binding (3.308×10-18), catalytic activity (2.158×10-10) and biogenesis (5.929×10-8). The PPI network resulted in 60 hub genes which were verified with data from TCGA, MET500, CPTAC and GTEx projects. Survival analyses with clinical data from TCGA showed that high expression of SRSF1, SRSF6, UBE2Z and PCF11, and low expression of HECW2 were correlated with poor prognosis in HMs. In summary, our study unraveled essential genes that could serve as potential biomarkers for prognosis and may serve as drug targets for HM management.

Unexplored Functions of Sex Hormones in Glioblastoma Cancer Stem Cells

Biological sex impacts a wide array of molecular and cellular functions that impact organismal development and can influence disease trajectory in a variety of pathophysiological states. In nonreproductive cancers, epidemiological sex differences have been observed in a series of tumors, and recent work has identified previously unappreciated sex differences in molecular genetics and immune response. However, the extent of these sex differences in terms of drivers of tumor growth and therapeutic response is less clear. In glioblastoma (GBM), the most common primary malignant brain tumor, there is a male bias in incidence and outcome, and key genetic and epigenetic differences, as well as differences in immune response driven by immune-suppressive myeloid populations, have recently been revealed. GBM is a prototypic tumor in which cellular heterogeneity is driven by populations of therapeutically resistant cancer stem cells (CSCs) that underlie tumor growth and recurrence. There is emerging evidence that GBM CSCs may show a sex difference, with male tumor cells showing enhanced self-renewal, but how sex differences impact CSC function is not clear. In this mini-review, we focus on how sex hormones may impact CSCs in GBM and implications for other cancers with a pronounced CSC population. We also explore opportunities to leverage new models to better understand the contribution of sex hormones vs sex chromosomes to CSC function. With the rising interest in sex differences in cancer, there is an immediate need to understand the extent to which sex differences impact tumor growth, including effects on CSC function.

RORγ is a context-specific master regulator of cholesterol biosynthesis and an emerging therapeutic target in cancer and autoimmune diseases

Aberrant cholesterol metabolism and homeostasis in the form of elevated cholesterol biosynthesis and dysregulated efflux and metabolism is well recognized as a major feature of metabolic reprogramming in solid tumors. Recent studies have emphasized on major drivers and regulators such as Myc, mutant p53, SREBP2, LXRs and oncogenic signaling pathways that play crucial roles in tumor cholesterol metabolic reprogramming. Therapeutics such as statins targeting the mevalonate pathway were tried at the clinic without showing consistent benefits to cancer patients. Nuclear receptors are prominent regulators of mammalian metabolism. Their de-regulation often drives tumorigenesis. RORγ and its immune cell-specific isoform RORγt play important functions in control of mammalian metabolism, circadian rhythm and immune responses. Although RORγ, together with its closely related members RORα and RORβ were identified initially as orphan receptors, recent studies strongly support the conclusion that specific intermediates and metabolites of cholesterol pathways serve as endogenous ligands of RORγ. More recent studies also reveal a critical role of RORγ in tumorigenesis through major oncogenic pathways including acting a new master-like regulator of tumor cholesterol biosynthesis program. Importantly, an increasing number of RORγ orthosteric and allosteric ligands are being identified that display potent activities in blocking tumor growth and autoimmune disorders in preclinical models. This review summarizes the recent preclinical and clinical progress on RORγ with emphasis on its role in reprogramming tumor cholesterol metabolism and its regulation. It will also discuss RORγ functional mechanisms, context-specificity and its value as a therapeutic target for effective cancer treatment.

Progesterone Receptors Promote Quiescence and Ovarian Cancer Cell Phenotypes via DREAM in p53-Mutant Fallopian Tube Models

CONTEXT

The ability of ovarian steroids to modify ovarian cancer (OC) risk remains controversial. Progesterone is considered to be protective; recent studies indicate no effect or enhanced OC risk. Knowledge of progesterone receptor (PR) signaling during altered physiology that typifies OC development is limited.

OBJECTIVE

This study defines PR-driven oncogenic signaling mechanisms in p53-mutant human fallopian tube epithelia (hFTE), a precursor of the most aggressive OC subtype.

METHODS

PR expression in clinical samples of serous tubal intraepithelial carcinoma (STIC) lesions and high-grade serous OC (HGSC) tumors was analyzed. Novel PR-A and PR-B isoform-expressing hFTE models were characterized for gene expression and cell cycle progression, emboli formation, and invasion. PR regulation of the DREAM quiescence complex and DYRK1 kinases was established.

RESULTS

STICs and HGSC express abundant activated phospho-PR. Progestin promoted reversible hFTE cell cycle arrest, spheroid formation, and invasion. RNAseq/biochemical studies revealed potent ligand-independent/-dependent PR actions, progestin-induced regulation of the DREAM quiescence complex, and cell cycle target genes through enhanced complex formation and chromatin recruitment. Disruption of DREAM/DYRK1s by pharmacological inhibition, HPV E6/E7 expression, or DYRK1A/B depletion blocked progestin-induced cell arrest and attenuated PR-driven gene expression and associated OC phenotypes.

CONCLUSION

Activated PRs support quiescence and pro-survival/pro-dissemination cell behaviors that may contribute to early HGSC progression. Our data support an alternative perspective on the tenet that progesterone always confers protection against OC. STICs can reside undetected for decades prior to invasive disease; our studies reveal clinical opportunities to prevent the ultimate development of HGSC by targeting PRs, DREAM, and/or DYRKs.

Baseline Serum Cholesterol Levels Predict the Response of Patients with Advanced Non-Small Cell Lung Cancer to Immune Checkpoint Inhibitor-Based Treatment

Purpose

Although predictive markers of immune checkpoint inhibitor (ICI)-based treatments have been extensively studied, with the exception of programmed death ligand 1 (PD-L1), most are not widely used in the clinic due to poor effects or defective practicability. The aim of this study was to identify those patients with high baseline serum cholesterol who benefit from ICI-based treatments.

Patients and Methods

Patients with advanced non-small cell lung cancer (NSCLC) treated at Ningbo Medical Center, Li Huili Hospital between August 2017 and December 2019 were enrolled in this retrospective study. The Response Evaluation Criteria in Solid Tumors (RECIST, version 1.1) were used to evaluate the efficacy of the ICI-based treatment. Progression-free survival (PFS) and overall survival (OS) were calculated using the Kaplan–Meier survival curves and compared using the log rank test. Univariate and multivariate analyses were conducted using the logistic regression analysis and Cox proportional hazards model. A receiver operating characteristic curve was created, and the area under the curve (AUC) was calculated to compare the predictive value of baseline serum cholesterol with PD-L1 expression for patient response to ICI-based treatment.

Results

In our cohort of 169 NSCLC patients, the objective response rate (ORR) and disease control rate (DCR) of the treatment were significantly higher in patients with hypercholesterolemia (>5.18 mmol/L) than in those with hypocholesterolemia (ORR: 33.67% vs 14.08%, P=0.004; DCR: 68.37% vs 42.25%, P=0.001). The median PFS was 7.9 months in the hypercholesterolemia group, significantly longer than in the hypocholesterolemia group (4.4 months, 95% CI: 4.620–7.380, P<0.001). The median OS in the two groups were 11 months and 8 months, with 95% CIs of 8.980–10.420 (P<0.001). The AUC for the baseline level of cholesterol was 0.706 (P<0.001), while it was 0.643 (P=0.001) for PD-L1 expression.

Conclusion

The baseline serum cholesterol level is predictive of a clinical benefit for advanced NSCLC patients who undergo ICI-based treatment, and hence it is a promising prognostic indicator for ICI-based treatment of NSCLC.

Microenvironmental Determinants of Breast Cancer Metastasis: Focus on the Crucial Interplay Between Estrogen and Insulin/Insulin-Like Growth Factor Signaling

The development and progression of the great majority of breast cancers (BCs) are mainly dependent on the biological action elicited by estrogens through the classical estrogen receptor (ER), as well as the alternate receptor named G-protein–coupled estrogen receptor (GPER). In addition to estrogens, other hormones and growth factors, including the insulin and insulin-like growth factor system (IIGFs), play a role in BC. IIGFs cooperates with estrogen signaling to generate a multilevel cross-communication that ultimately facilitates the transition toward aggressive and life-threatening BC phenotypes. In this regard, the majority of BC deaths are correlated with the formation of metastatic lesions at distant sites. A thorough scrutiny of the biological and biochemical events orchestrating metastasis formation and dissemination has shown that virtually all cell types within the tumor microenvironment work closely with BC cells to seed cancerous units at distant sites. By establishing an intricate scheme of paracrine interactions that lead to the expression of genes involved in metastasis initiation, progression, and virulence, the cross-talk between BC cells and the surrounding microenvironmental components does dictate tumor fate and patients’ prognosis. Following (i) a description of the main microenvironmental events prompting BC metastases and (ii) a concise overview of estrogen and the IIGFs signaling and their major regulatory functions in BC, here we provide a comprehensive analysis of the most recent findings on the role of these transduction pathways toward metastatic dissemination. In particular, we focused our attention on the main microenvironmental targets of the estrogen-IIGFs interplay, and we recapitulated relevant molecular nodes that orientate shared biological responses fostering the metastatic program. On the basis of available studies, we propose that a functional cross-talk between estrogens and IIGFs, by affecting the BC microenvironment, may contribute to the metastatic process and may be regarded as a novel target for combination therapies aimed at preventing the metastatic evolution.

Roles of Farnesyl-Diphosphate Farnesyltransferase 1 in Tumour and Tumour Microenvironments

Farnesyl-diphosphate farnesyltransferase 1 (FDFT1, squalene synthase), a membrane-associated enzyme, synthesizes squalene via condensation of two molecules of farnesyl pyrophosphate. Accumulating evidence has noted that FDFT1 plays a critical role in cancer, particularly in metabolic reprogramming, cell proliferation, and invasion. Based on these advances in our knowledge, FDFT1 could be a potential target for cancer treatment. This review focuses on the contribution of FDFT1 to the hallmarks of cancer, and further, we discuss the applicability of FDFT1 as a cancer prognostic marker and target for anticancer therapy.

Alterations in Progesterone Receptor Isoform Balance in Normal and Neoplastic Breast Cells Modulates the Stem Cell Population

To investigate the role of PR isoforms on the homeostasis of stem cells in the normal and neoplastic mammary gland, we used PRA and PRB transgenic mice and the T47D human breast cancer cell line and its derivatives, T47D YA and YB (manipulated to express only PRA or PRB, respectively). Flow cytometry and mammosphere assays revealed that in murine breast, overexpression of PRB leads to an increase in luminal and basal progenitor/stem cells. Ovariectomy had a negative impact on the luminal compartment and induced an increase in mammosphere-forming capacity in cells derived from WT and PRA mice only. Treatment with ICI 182,780 augmented the mammosphere-forming capacity of cells isolated from WT and PRA mice, whilst those from PRB remained unaltered. T47D YB cells showed an increase in the CD44⁺/CD24^Low/- subpopulation; however, the number of tumorspheres did not vary relative to T47D and YA, even though they were larger, more irregular, and had increased clonogenic capacity. T47D and YA tumorspheres were modulated by estrogen/antiestrogens, whereas YB spheres remained unchanged in size and number. Our results show that alterations in PR isoform balance have an impact on normal and tumorigenic breast progenitor/stem cells and suggest a key role for the B isoform, with implications in response to antiestrogens.

Involvement of the Estrogen and Progesterone Axis in Cancer Stemness: Elucidating Molecular Mechanisms and Clinical Significance

Estrogen and progesterone regulate the growth and development of human tissues, including the reproductive system and breasts, through estrogen and progesterone receptors, respectively. These receptors are also important indicators for the clinical prognosis of breast cancer and various reproductive cancers. Many studies have reported that cancer stem cells (CSCs) play a key role in tumor initiation, progression, metastasis, and recurrence. Although the role of estrogen and progesterone in human organs and various cancers has been studied, the molecular mechanisms underlying the action of these hormones on CSCs remain unclear. Therefore, further elucidation of the effects of estrogen and progesterone on CSCs should provide a new direction for developing pertinent therapies. In this review, we summarize the current knowledge on the estrogen and progesterone axis involved in cancer stemness and discuss potential therapeutic strategies to inhibit CSCs by targeting relevant pathways.

QSOX1 promotes mitochondrial apoptosis of hepatocellular carcinoma cells during anchorage-independent growth by inhibiting lipid synthesis

Anoikis is a programmed death of cell induced upon detachment from the extracellular matrix (ECM). Resistance to anoikis is a critical contributor to cancer invasion and metastasis. High frequency of metastatic recurrence is a huge challenge for current therapy of hepatocellular carcinoma (HCC). Our previous study had identified sulfhydryl oxidase 1 (QSOX1) as a suppressor of HCC metastasis. In the present study, we used the anchorage-independent growth condition to mimic the detachment of HCC cells from ECM. We found that QSOX1 was induced in HCC cells under the anchorage-independent growth condition and that could be blocked by endoplasmic reticulum stress (ERS) inhibitor. Overexpression and knockdown of QSOX1 gene were performed on HCC cells. QSOX1 inhibited de novo synthesis of fatty acids (FAs) and cholesterol (ChE) and reduced their content in the detached HCC cells, and thus mediated mitochondrial apoptosis of HCC cells. In conclusion, QSOX1 is induced under detached culture condition via ERS. QSOX1 promotes mitochondrial apoptosis by suppressing the lipid synthesis of HCC cells in detached condition. QSOX1 appears to accelerate anoikis of HCC cells. These findings offer a new insight into how to overcome anoikis resistance of HCC cells and provide a potential target for prevention of HCC metastasis.

90 YEARS OF PROGESTERONE: Progesterone and progesterone receptors in breast cancer: past, present, future

Progesterone and progesterone receptors (PR) have a storied albeit controversial history in breast cancers. As endocrine therapies for breast cancer progressed through the twentieth century from oophorectomy to antiestrogens, it was recognized in the 1970s that the presence of estrogen receptors (ER) alone could not efficiently predict treatment responses. PR, an estrogen regulated protein, became the first prognostic and predictive marker of response to endocrine therapies. It remains today as the gold standard for predicting the existence of functional, targetable ER in breast malignancies. PRs were subsequently identified as highly structured transcription factors that regulate diverse physiological processes in breast cancer cells. In the early 2000s, the somewhat surprising finding that prolonged use of synthetic progestin-containing menopausal hormone therapies was associated with increased breast cancer incidence raised new questions about the role of PR in 'tumorigenesis'. Most recently, PR have been linked to expansion of cancer stem cells that are postulated to be the principal cells reactivated in occult or dormant disease. Other studies establish PR as dominant modulators of ER activity. Together, these findings mark PR as bona fide targets for progestin or antiprogestin therapies, yet their diverse actions have confounded that use. Here we summarize the early history of PR in breast cancer; debunk the theory that progesterone causes cancer; discuss recent discoveries that PR regulate cell heterogeneity; attempt to unify theories describing PR as either good or bad actors in tumors; and discuss emerging areas of research that may help explain this enigmatic hormone and receptor.

90 YEARS OF PROGESTERONE: Steroid receptors as MAPK signaling sensors in breast cancer: let the fates decide

Steroid hormone receptors (SRs) are classically defined as ligand-activated transcription factors that function as master regulators of gene programs important for a wide range of processes governing adult physiology, development, and cell or tissue homeostasis. A second function of SRs includes the ability to activate cytoplasmic signaling pathways. Estrogen (ER), androgen (AR), and progesterone (PR) receptors bind directly to membrane-associated signaling molecules including mitogenic protein kinases (i.e. c-SRC and AKT), G-proteins, and ion channels to mediate context-dependent actions via rapid activation of downstream signaling pathways. In addition to making direct contact with diverse signaling molecules, SRs are further fully integrated with signaling pathways by virtue of their N-terminal phosphorylation sites that act as regulatory hot-spots capable of sensing the signaling milieu. In particular, ER, AR, PR, and closely related glucocorticoid receptors (GR) share the property of accepting (i.e. sensing) ligand-independent phosphorylation events by proline-directed kinases in the MAPK and CDK families. These signaling inputs act as a 'second ligand' that dramatically impacts cell fate. In the face of drugs that reliably target SR ligand-binding domains to block uncontrolled cancer growth, ligand-independent post-translational modifications guide changes in cell fate that confer increased survival, EMT, migration/invasion, stemness properties, and therapy resistance of non-proliferating SR+ cancer cell subpopulations. The focus of this review is on MAPK pathways in the regulation of SR+ cancer cell fate. MAPK-dependent phosphorylation of PR (Ser294) and GR (Ser134) will primarily be discussed in light of the need to target changes in breast cancer cell fate as part of modernized combination therapies.

Breast cancer in low-middle income countries: abnormality in splicing and lack of targeted treatment options

Breast cancer is a common malignancy among women worldwide. Regardless of the economic status of a country, breast cancer poses a burden in prevention, diagnosis and treatment. Developed countries such as the U.S. have high incidence and mortality rates of breast cancer. Although low incidence rates are observed in developing countries, the mortality rate is on the rise implying that low- to middle-income countries lack the resources for preventative screening for early detection and adequate treatment resources. The differences in incidence between countries can be attributed to changes in exposure to environmental risk factors, behaviour and lifestyle factors of the different population groups. Genomic modifications are an important factor that significantly alters the risk profile of breast tumourigenesis. The incidence of early-onset breast cancer is increasing and evidence shows that early onset of breast cancer is far more aggressive than late onset of the disease; possibly due to the difference in genetic alterations or tumour biology. Alternative splicing is a pivotal factor in the progressions of breast cancer. It plays a significant role in tumour prognosis, survival and drug resistance; hence, it offers a valuable option as a therapeutic target. In this review, the differences in breast cancer incidence and mortality rates in developed countries will be compared to low- to middle-income countries. The review will also discuss environmental and lifestyle risk factors, and the underlying molecular mechanisms, genetic variations or mutations and alternative splicing that may contribute to the development and novel drug targets for breast cancer.

Progesterone and Breast Cancer

Synthetic progestogens (progestins) have been linked to increased breast cancer risk; however, the role of endogenous progesterone in breast physiology and carcinogenesis is less clearly defined. Mechanistic studies using cell culture, tissue culture, and preclinical models implicate progesterone in breast carcinogenesis. In contrast, limited epidemiologic data generally do not show an association of circulating progesterone levels with risk, and it is unclear whether this reflects methodologic limitations or a truly null relationship. Challenges related to defining the role of progesterone in breast physiology and neoplasia include: complex interactions with estrogens and other hormones (eg, androgens, prolactin, etc.), accounting for timing of blood collections for hormone measurements among cycling women, and limitations of assays to measure progesterone metabolites in blood and progesterone receptor isotypes (PRs) in tissues. Separating the individual effects of estrogens and progesterone is further complicated by the partial dependence of PR transcription on estrogen receptor (ER)α-mediated transcriptional events; indeed, interpreting the integrated interaction of the hormones may be more essential than isolating independent effects. Further, many of the actions of both estrogens and progesterone, particularly in "normal" breast tissues, are driven by paracrine mechanisms in which ligand binding to receptor-positive cells evokes secretion of factors that influence cell division of neighboring receptor-negative cells. Accordingly, blood and tissue levels may differ, and the latter are challenging to measure. Given conflicting data related to the potential role of progesterone in breast cancer etiology and interest in blocking progesterone action to prevent or treat breast cancer, we provide a review of the evidence that links progesterone to breast cancer risk and suggest future directions for filling current gaps in our knowledge.

Cholesterol metabolism in cancer: mechanisms and therapeutic opportunities

Cholesterol metabolism produces essential membrane components as well as metabolites with a variety of biological functions. In the tumour microenvironment, cell-intrinsic and cell-extrinsic cues reprogram cholesterol metabolism and consequently promote tumourigenesis. Cholesterol-derived metabolites play complex roles in supporting cancer progression and suppressing immune responses. Preclinical and clinical studies have shown that manipulating cholesterol metabolism inhibits tumour growth, reshapes the immunological landscape and reinvigorates anti-tumour immunity. Here, we review cholesterol metabolism in cancer cells, its role in cancer progression and the mechanisms through which cholesterol metabolites affect immune cells in the tumour microenvironment. We also discuss therapeutic strategies aimed at interfering with cholesterol metabolism, and how the combination of such approaches with existing anti-cancer therapies can have synergistic effects, thus offering new therapeutic opportunities.

Reproductive Factors and Breast Cancer Risk in Lithuanian Women: A Population-Based Cohort Study

Abstract. Background.

Although the relationship between reproductive factors and breast cancer is internationally proved, reliable data on former USSR countries are scarce. This study examines the association of parity, age at the first childbirth, number of children, and breast cancer risk in Lithuanian women.

Methods.

The study that included women from 40 to 79 years old was based on a dataset that was made up linking all records from the 2001 census, all cancer incidence records from the Lithuanian Cancer Registry and all death records from Statistics Lithuania between 6th April 2001 and 31st December 2009. Cox’s proportional hazards regression models were used to estimate the hazard ratios (HRs) for parity, age at the first childbirth, and number of children.

Results.

If compared to nulliparous women, parous women had a lower risk of breast cancer (HR=0.84, 95% CI 0.78–0.89) and this risk further decreased with an increasing number of children. Women who gave birth after the age of 25 had a significantly higher risk of breast cancer. This disadvantage became statistically insignificant or decreased after controlling for total number of children.

Conclusions.

Parity and age at the first childbirth are strong predictors of breast cancer risk among Lithu-anian women.

Breast cancer stem cells: The role of sex steroid receptors

Breast cancer (BC) is the most common cancer among women, and current available therapies often have high success rates. Nevertheless, BC might acquire drug resistance and sometimes relapse. Current knowledge about the most aggressive forms of BC points to the role of specific cells with stem properties located within BC, the so-called “BC stem cells” (BCSCs). The role of BCSCs in cancer formation, growth, invasiveness, therapy resistance and tumor recurrence is becoming increasingly clear. The growth and metastatic properties of BCSCs are regulated by different pathways, which are only partially known. Sex steroid receptors (SSRs), which are involved in BC etiology and progression, promote BCSC proliferation, dedifferentiation and migration. However, in the literature, there is incomplete information about their roles. Particularly, there are contrasting conclusions about the expression and role of the classical BC hormonal biomarkers, such as estrogen receptor alpha (ERα), together with scant, albeit promising information concerning ER beta (ERβ) and androgen receptor (AR) properties that control different transduction pathways in BCSCs. In this review, we will discuss the role that SRs expressed in BCSCs play to BC progression and recurrence and how these findings have opened new therapeutic possibilities.

Effect of age at first use of oral contraceptives on breast cancer risk: An updated meta-analysis

BACKGROUND

We evaluated the relationship between the age at first use of oral contraceptives (OC) and breast cancer (BC) risk.

METHODS

We searched PubMed, Embase, and related reviews published through June 28, 2018, and used summary relative risk (RR) and 95% confidence intervals (CIs) to evaluate the cancer risks, and fixed-effects dose-response meta-analysis to assess potential linear and non-linear dose-response relationships.

RESULTS

We included 10 studies, with 8585 BC cases among 686,305 participants. The pooled RR for BC was 1.24 (95% CI: 1.10-1.41), with moderate heterogeneities (I = 66.5%, P < .001). No significant publication bias was found (P = .584 for Begg test, P = .597 for Egger test). A linear dose-response relationship between the age at first OC use and BC risk was detected (P = .518 for non-linearity). Subgroup analyses were restricted to studies done by BC subtypes, region, sample size, follow-up time and study quality. Inconsistent consequences with no statistical significance were explored when limited to studies from Western countries, study quality <7, sample size <10,000, follow-up time <5 years, and BC subtypes defined by estrogen receptor (ER), progesterone receptor (PR) and human epidermal growth factor receptor-2 (HER-2) expression status in tumor tissue. Sensitivity analyses indicated that our results were stable and reliable after removing each study in turn and omitting studies of adjusted unreported variables.

CONCLUSION

A significant linear relationship between the age at first OC use and BC risk was confirmed. No further consistent differences are noted in multiple aspects of BC subtypes defined by progesterone or ER status.

Proteomics contribution to the elucidation of the steroid hormone receptors functions

Steroid hormones have far-ranging biological impacts and more are continuously being uncovered. Over the last decades, proteomics approaches have become key to better understand biological processes. Due to multiple technical breakthroughs allowing for the concurrent identification and/or quantification of thousands of analytes using mass spectrometers, researchers employing proteomics tools today can now obtain truly holistic views of multiple facets of the human proteome. Here, we review how the field of proteomics has contributed to discoveries about steroid hormones, their receptors and their impact on human pathologies. In particular, the involvement of steroid receptors in cancer initiation, development, metastasis and treatment will be highlighted. Techniques at the forefront of the proteomics field will also be discussed to present how they can contribute to a better understanding of steroid hormone receptors.

Phosphorylated Progesterone Receptor Isoforms Mediate Opposing Stem Cell and Proliferative Breast Cancer Cell Fates

Progesterone receptors (PRs) are key modifiers of estrogen receptor (ER) target genes and drivers of luminal breast cancer progression. Total PR expression, rather than isoform-specific PR expression, is measured in breast tumors as an indicator of functional ER. We identified phenotypic differences between PR-A and PR-B in luminal breast cancer models with a focus on tumorsphere biology. Our findings indicated that PR-A is a dominant driver of cancer stem cell (CSC) expansion in T47D models, and PR-B is a potent driver of anchorage-independent proliferation. PR-A+ tumorspheres were enriched for aldehyde dehydrogenase (ALDH) activity, CD44+/CD24-, and CD49f+/CD24- cell populations relative to PR-B+ tumorspheres. Progestin promoted heightened expression of known CSC-associated target genes in PR-A+ but not PR-B+ cells cultured as tumorspheres. We report robust phosphorylation of PR-A relative to PR-B Ser294 and found that this residue is required for PR-A-induced expression of CSC-associated genes and CSC behavior. Cells expressing PR-A S294A exhibited impaired CSC phenotypes but heightened anchorage-independent cell proliferation. The PR target gene and coactivator, FOXO1, promoted PR phosphorylation and tumorsphere formation. The FOXO1 inhibitor (AS1842856) alone or combined with onapristone (PR antagonist), blunted phosphorylated PR, and tumorsphere formation in PR-A+ and PR-B+ T47D, MCF7, and BT474 models. Our data revealed unique isoform-specific functions of phosphorylated PRs as modulators of distinct and opposing pathways relevant to mechanisms of late recurrence. A clear understanding of PR isoforms, phosphorylation events, and the role of cofactors could lead to novel biomarkers of advanced tumor behavior and reveal new approaches to pharmacologically target CSCs in luminal breast cancer.

Breast cancer stem cells: Features, key drivers and treatment options

The current view is that breast cancer is a stem cell disease characterized by the existence of cancer cells with stem-like features and tumor-initiating potential. These cells are made responsible for tumor dissemination and metastasis. Common therapies by chemotherapeutic drugs fail to eradicate these cells and rather increase the pool of cancer stem cells in tumors, an effect that may increase the likelyhood of recurrence. Fifteen years after the first evidence for a small stem-like subpopulation playing a major role in breast cancer initiation has been published a large body of knowledge has been accumulated regarding the signaling cascades and proteins involved in maintaining stemness in breast cancer. Differences in the stem cell pool size and in mechanisms regulating stemness in the different breast cancer subtypes have emerged. Overall, this knowledge offers new approaches to intervene with breast cancer stem cell activity. New options are particularly needed for the treatment of triple-negative breast cancer subtype, which is particularly rich in cancer stem cells and is also the subtype for which specific therapies are still not available.