Modulation of JAK-STAT Signaling by LNK: A Forgotten Oncogenic Pathway in Hormone Receptor-Positive Breast Cancer

Roles of Post-Translational Modifications of Transcription Factors Involved in Breast Cancer Hypoxia

BC is the most commonly diagnosed cancer and the second leading cause of cancer death among women worldwide. Cellular stress is a condition that leads to disrupted homeostasis by extrinsic and intrinsic factors. Among other stressors, hypoxia is a driving force for breast cancer (BC) progression and a general hallmark of solid tumors. Thus, intratumoral hypoxia is an important determinant of invasion, metastasis, treatment failure, prognosis, and patient mortality. Acquisition of the epithelial-mesenchymal transition (EMT) phenotype is also a consequence of tumor hypoxia. The cellular response to hypoxia is mainly regulated by the hypoxia signaling pathway, governed by hypoxia-inducible factors (HIFs), mainly HIF1α. HIFs are a family of transcription factors (TFs), which induce the expression of target genes involved in cell survival and proliferation, metabolic reprogramming, angiogenesis, resisting apoptosis, invasion, and metastasis. HIF1α cooperates with a large number of other TFs. In this review, we focused on the crosstalk and cooperation between HIF1α and other TFs involved in the cellular response to hypoxia in BC. We identified a cluster of TFs, proposed as the HIF1α-TF interactome, that orchestrates the transcription of target genes involved in hypoxia, due to their post-translational modifications (PTMs), including phosphorylation/dephosphorylation, ubiquitination/deubiquitination, SUMOylation, hydroxylation, acetylation, S-nitrosylation, and palmitoylation. PTMs of these HIF1α-related TFs drive their stability and activity, degradation and turnover, and the bidirectional translocation between the cytoplasm or plasma membrane and nucleus of BC cells, as well as the transcription/activation of proteins encoded by oncogenes or inactivation of tumor suppressor target genes. Consequently, PTMs of TFs in the HIF1α interactome are crucial regulatory mechanisms that drive the cellular response to oxygen deprivation in BC cells.

Matrix metalloproteinases: Master regulators of tissue morphogenesis

The matrix metalloproteinases (MMPs) are a class of zinc proteases that aid in breaking most of the extracellular matrix's (ECM) constituents. Additionally, MMPs play a part in processing elements that affect inflammation, cell development and proliferation, and many more. In vivo genetic study of the Drosophila MMPs Mmp1 and Mmp2 reveals they are essential for tissue remodeling but not embryonic development. The canonical and conserved MMP domain organization is present in both fly MMPs. Because Mmp2 appeared to be membrane-anchored and Mmp1 appeared to be released, the pericellular localization of Drosophila MMPs has been used to classify them. This suggests that the protein's localization is the critical distinction in this small MMP family. The signal sequence, the propeptide, the catalytic domain, and the hemopexin-like domain are among the numerous domains found in MMPs. Following secretion from the extracellular environment to the endoplasmic reticulum, the pre-domain, also known as the signal sequence, serves to direct MMP production. MMPs of the secretory and membrane types (MT-MMPs) are two groups of MMPs that have been widely recognized. Subgroups of MMPs are categorized based on their structure and function. While analysis of the intracellular activity of human MMPs is challenging because the human genome contains around 23 distinct MMPs with overlapping functions, only two MMPs, dMMP1 and dMMP2, are encoded by the Drosophila melanogaster genome. On the other hand, the balance between MMPs and the family members are implicated in various pathophysiology/progression of diseases, but whether or not the mechanisms of MMP inhibition are not clearly understood as master regulators. In this review, we outline the role of MMPs as master regulators of tissue morphogenesis.

Targeting the JAK-STAT pathway in colorectal cancer: mechanisms, clinical implications, and therapeutic potential

Colorectal cancer (CRC) remains one of the most prevalent and fatal malignancies worldwide, consistently ranking among the top three in terms of incidence and mortality. Despite notable advancements in early detection and therapeutic interventions, survival outcomes for advanced-stage CRC are still dismal, largely due to issues such as drug resistance and metastasis. Recent research has increasingly implicated the JAK-STAT signaling pathway as a pivotal contributor to CRC pathogenesis. This evolutionarily conserved pathway plays a key role in transmitting extracellular signals to the nucleus, thereby modulating gene expression involved in numerous fundamental biological processes. In CRC, dysregulation of the JAK-STAT pathway is frequently observed and is strongly associated with tumor progression, including processes such as cellular proliferation, apoptosis, metastasis, immune evasion, and the sustenance of cancer stem cells. Given its integral role in CRC advancement, the JAK-STAT pathway has gained recognition as a viable therapeutic target. Extensive evidence from preclinical and clinical models supports the efficacy and safety of targeting components of the JAK-STAT pathway, presenting new therapeutic possibilities for patients with CRC, particularly in addressing drug resistance and enhancing treatment outcomes. This review offers a detailed exploration of the JAK-STAT pathway, focusing on its regulatory mechanisms in CRC-related malignancies. Moreover, it examines the association between JAK-STAT protein expression, clinical features, prognosis, and its therapeutic potential in CRC management.

[High KHSRP expression promotes gastric adenocarcinoma metastasis: the mediating role of the JAK1/STAT3 signaling axis]

OBJECTIVE

To investigate the regulatory effect of KHSRP on progression of gastric adenocarcinoma and the role of the JAK1/STAT3 signaling axis in mediating its effect.

METHODS

KHSRP mRNA expression level was detected using qRT-PCR in 120 pairs of gastric adenocarcinoma and adjacent tissues, 4 gastric adenocarcinoma cell lines (MKN-28, HGC-27, CRL-5822, and SNU-1) and normal human gastric mucosal GES-1 cells. In HGC-27 cells with KHSRP knockdown and SNU-1 cells with KHSRP overexpression, cell proliferation, migration, invasion and expression levels of JAK/STAT were evaluated using CCK-8 assay, Transwell migration and invasion assays, and Western blotting. In BALB/c-nude mice, HGC-27 cells with KHSRP knockdown and SNU-1 cells overexpressing KHSRP were injected either subcutaneous or via the tail vein to observe subcutaneous xenograft growth and lung metastasis of the tumor cells.

RESULTS

Gastric adenocarcinoma tissues and cell lines all showed significantly increased KHSRP expression as compared with the adjacent tissues and GES-1 cells. In HGC-27 cells, KHSRP knockdown significantly inhibited cell proliferation, migration and invasion, while KHSRP overexpression enhanced the malignant behaviors of SNU-1 cells. In nude mice, inoculation of HGC-27 cells with KHSRP knockdown resulted in smaller tumor volume and weight, slower cell proliferation rate and fewer lung metastatic foci, and KHSRP-overexpressing SNU-1 cells produced the opposite results. KHSRP knockdown in HGC-27 cells significantly down-regulated the expression levels of JAK1 and STAT3, which were obviously increased in KHSRP-overexpressing SNU-1 cells.

CONCLUSION

High expressions of KHSRP promote progression and metastasis of gastric adenocarcinoma possibly by regulating the JAK1/STAT3 signaling axis.

Role of microRNAs in triple‑negative breast cancer and new therapeutic concepts (Review)

Breast cancer has surpassed lung cancer as the most prevalent malignancy affecting women worldwide. Triple-negative breast cancer (TNBC) is the type of breast cancer with the worst prognosis. As a heterogeneous disease, TNBC has a pathogenesis that involves multiple oncogenic pathways, including involvement of gene mutations and alterations in signaling pathways. MicroRNAs (miRNAs) are small endogenous, single-stranded non-coding RNAs that bind to the 3' untranslated region of target cell mRNAs to negatively regulate the gene expression of these specific mRNAs. Therefore, miRNAs are involved in cell growth, development, division and differentiation stages. miRNAs are also involved in gene targeting in tumorigenesis, tumor growth and the regulation of metastasis, including in breast cancer. Meanwhile, miRNAs also regulate components of signaling pathways. In this review, the role of miRNAs in the TNBC signaling pathway discovered in recent years is described in detail. The new concept of bi-targeted therapy for breast cancer using miRNA and artificial intelligence is also discussed.

The intersection of the nervous system and breast cancer

Breast cancer (BC) represents a paradigm of heterogeneity, manifesting as a spectrum of molecular subtypes with divergent clinical trajectories. It is fundamentally characterized by the aberrant proliferation of malignant cells within breast tissue, a process modulated by a myriad of factors that govern its progression. Recent endeavors outline the interplay between BC and the nervous system, illuminate the complex symbiosis between neural structures and neoplastic cells, and elucidate nerve dependence as a cornerstone of BC progression. This includes the neural modulations on immune response, neurovascular formation, and multisystem interactions. Such insights have unveiled the critical impact of neural elements on tumor dynamics and patient prognosis. This revelation beckons a deeper exploration into the neuro-oncological interface, potentially unlocking novel therapeutic vistas. This review endeavors to delineate the intricate mechanisms between the nervous system and BC, aiming to accentuate the implications and therapeutic strategies of this intersection for tumor evolution and the formulation of innovative therapeutic approaches.

Role of MicroRNA-204 in Regulating the Hallmarks of Breast Cancer: An Update

microRNA-204-5p (miR-204) is a small noncoding RNA with diverse regulatory roles in breast cancer (BC) development and progression. miR-204 is implicated in the instauration of fundamental traits acquired during the multistep development of BC, known as the hallmarks of cancer. It may act as a potent tumor suppressor by inhibiting key cellular processes like angiogenesis, vasculogenic mimicry, invasion, migration, and metastasis. It achieves this by targeting multiple master genes involved in these processes, including HIF-1α, β-catenin, VEGFA, TGFBR2, FAK, FOXA1, among others. Additionally, miR-204 modulates signaling pathways like PI3K/AKT and interacts with HOTAIR and DSCAM-AS1 lncRNAs, further influencing tumor progression. Beyond its direct effects on tumor cells, miR-204 shapes the tumor microenvironment by regulating immune cell infiltration, suppressing pro-tumorigenic cytokine production, and potentially influencing immunotherapy response. Moreover, miR-204 plays a crucial role in metabolic reprogramming by directly suppressing metabolic genes within tumor cells, indirectly affecting metabolism through exosome signaling, and remodeling metabolic flux within the tumor microenvironment. This review aims to present an update on the current knowledge regarding the role of miR-204 in the hallmarks of BC. In conclusion, miR-204 is a potential therapeutic target and prognostic marker in BC, emphasizing the need for further research to fully elucidate its complex roles in orchestrating aggressive BC behavior.

Ruxolitinib-loaded poly-ɛ-caprolactone (PCL) nanoparticles inhibit JAK2/STAT5 signaling in BT474 breast cancer cells by downregulating Bcl-2 and Mcl-1

BACKGROUND

JAK/STAT signaling plays an important role in regulating cell proliferation. Reducing proliferation and inducing cell death with gene-specific inhibitors such as ruxolitinib, Receptor tyrosine kinases (RTK) inhibitor targeting JAK1/2, are therapeutic approaches. The use of nanoparticles can reduce the toxicity and side effects of drugs, as they act directly on cancer cells and can selectively increase drug accumulation in tumor cells. Poly-ɛ-caprolactone (PCL) is a polymer that is frequently used in drug development. In this study, Rux-PCL-NPs were synthesized to increase the effectiveness of ruxolitinib. In addition, this study aimed to determine the effect of Rux-PCL-NPs on JAK/STAT signaling and apoptotic cell death.

METHODS AND RESULTS

Rux-PCL-NPs were synthesized by nanoprecipitation. The Rux-PCL-NPs had a spherical and mean particle size of 219 ± 88.66 nm and a zeta potential of 0.471 ± 0.453 mV. In vitro cytotoxicity and antiproliferative effects were determined by MTT and soft agar colony formation assays, respectively. The effects of ruxolitinib, PCL-NPs, and Rux-PCL-NPs on apoptosis and the JAK/STAT pathway in cells were examined by western blot analysis. PCL-NPs did not have a toxic effect on the cells. The IC50 value of Rux-PCL-NPs was decreased 50-fold compared to that of ruxolitinib. Rux-PCL-NPs promoted cell death by downregulating JAK2 and STAT5, thereby inhibiting the JAK/STAT pathway.

CONCLUSIONS

Our results revealed that Rux-PCL-NPs, which increased the efficacy of ruxolitinib, regulated apoptosis and the JAK2/STAT5 pathway.

Coordinated inflammation and immune response transcriptional regulation in breast cancer molecular subtypes

Breast cancer, characterized by its complexity and diversity, presents significant challenges in understanding its underlying biology. In this study, we employed gene co-expression network analysis to investigate the gene composition and functional patterns in breast cancer subtypes and normal breast tissue. Our objective was to elucidate the detailed immunological features distinguishing these tumors at the transcriptional level and to explore their implications for diagnosis and treatment. The analysis identified nine distinct gene module clusters, each representing unique transcriptional signatures within breast cancer subtypes and normal tissue. Interestingly, while some clusters exhibited high similarity in gene composition between normal tissue and certain subtypes, others showed lower similarity and shared traits. These clusters provided insights into the immune responses within breast cancer subtypes, revealing diverse immunological functions, including innate and adaptive immune responses. Our findings contribute to a deeper understanding of the molecular mechanisms underlying breast cancer subtypes and highlight their unique characteristics. The immunological signatures identified in this study hold potential implications for diagnostic and therapeutic strategies. Additionally, the network-based approach introduced herein presents a valuable framework for understanding the complexities of other diseases and elucidating their underlying biology.

The interactions between CpG oligodeoxynucleotides and Toll-like receptors in Pacific white shrimp Litopenaeus vannamei

CpG oligodeoxynucleotides (ODNs), as a novel type of adjuvant with immunomodulatory effects, are recognized by Toll-like receptors (TLRs) in Litopenaeus vannamei. In the present study, eleven LvTLRs-pCMV recombinants (rLvTLRs) were constructed to investigate the relationships between various CpG ODNs and different LvTLRs in human embryonic kidney 293T (HEK293T) cells, which was further confirmed by bio-layer interferometry (BLI) technique. The results of dual luciferase reporter assay showed that every LvTLR could activate multiple downstream genes, mainly including NF-κB, CREB, ISRE, IL-6-promoter, TNF-α-promoter and Myc, thereby inducing main signaling pathways in shrimps. Most CpG ODNs possessed affinities to more than one LvTLR, while each LvTLR could recognize multiple CpG ODNs, and the widely recognized ligands within CpG ODNs are A-class and B-class. Moreover, BLI analysis showed that CpG 2216, Cpg 2006, CpG 2143 and CpG 21425 exhibited dose-dependent affinity to the expressed TLR protein, which were consistent with the results in HEK293T cells. It suggested that the interactions of CpG ODNs with LvTLRs were indispensable for the immune regulation triggered by CpG ODNs, and these findings would lay foundations for studying the activations of LvTLRs to immune signaling pathways and shedding lights on the immune functions and mechanisms of CpG ODNs.

Application of the Key Characteristics Framework to Identify Potential Breast Carcinogens Using Publicly Available in Vivo, in Vitro, and in Silico Data

BACKGROUND

Chemicals that induce mammary tumors in rodents or activate estrogen or progesterone signaling are likely to increase breast cancer (BC) risk. Identifying chemicals with these activities can prompt steps to protect human health.

OBJECTIVES

We compiled data on rodent tumors, endocrine activity, and genotoxicity to assess the key characteristics (KCs) of rodent mammary carcinogens (MCs), and to identify other chemicals that exhibit these effects and may therefore increase BC risk.

METHODS

Using authoritative databases, including International Agency for Research on Cancer (IARC) Monographs and the US Environmental Protection's (EPA) ToxCast, we selected chemicals that induce mammary tumors in rodents, stimulate estradiol or progesterone synthesis, or activate the estrogen receptor (ER) in vitro. We classified these chemicals by their genotoxicity and strength of endocrine activity and calculated the overrepresentation (enrichment) of these KCs among MCs. Finally, we evaluated whether these KCs predict whether a chemical is likely to induce mammary tumors.

RESULTS

We identified 279 MCs and an additional 642 chemicals that stimulate estrogen or progesterone signaling. MCs were significantly enriched for steroidogenicity, ER agonism, and genotoxicity, supporting the use of these KCs to predict whether a chemical is likely to induce rodent mammary tumors and, by inference, increase BC risk. More MCs were steroidogens than ER agonists, and many increased both estradiol and progesterone. Enrichment among MCs was greater for strong endocrine activity vs. weak or inactive, with a significant trend.

DISCUSSION

We identified hundreds of compounds that have biological activities that could increase BC risk and demonstrated that these activities are enriched among MCs. We argue that many of these should not be considered low hazard without investigating their ability to affect the breast, and chemicals with the strongest evidence can be targeted for exposure reduction. We describe ways to strengthen hazard identification, including improved assessments for mammary effects, developing assays for more KCs, and more comprehensive chemical testing. https://doi.org/10.1289/EHP13233.

Metastatic ER+ Breast Cancer: Mechanisms of Resistance and Future Therapeutic Approaches

Endocrine therapy is the main treatment for hormone receptor-positive (HR+) breast cancer. However, advanced tumors develop resistance to endocrine therapy, rendering it ineffective as the disease progresses. There are several molecular mechanisms of primary and secondary endocrine resistance. Resistance can develop due to either alteration of the estrogen receptor pathway (e.g., ESR1 mutations) or upstream growth factors signaling pathways (e.g., PI3K/Akt/mTOR pathway). Despite progress in the development of molecularly targeted anticancer therapies, the emergence of resistance remains a major limitation and an area of unmet need. In this article, we review the mechanisms of acquired endocrine resistance in HR+ advanced breast cancer and discuss current and future investigational therapeutic approaches.