Primaquine Inhibits the Endosomal Trafficking and Nuclear Localization of EGFR and Induces the Apoptosis of Breast Cancer Cells by Nuclear EGFR/Stat3-Mediated c-Myc Downregulation

Lost in Rotation: How TiO2 and ZnO Nanoparticles Disrupt Coordinated Epithelial Cell Rotation

Coordinated cell movement is a cardinal feature in tissue organization that highlights the importance of cells working together as a collective unit. Disruptions to this synchronization can have far-reaching pathological consequences, ranging from developmental disorders to tissue repair impairment. Herein, it is shown that metal oxide nanoparticles (NPs), even at low and non-toxic doses (1 and 10 µg mL-1), can perturb the coordinated epithelial cell rotation (CECR) in micropatterned human epithelial cell clusters via distinct nanoparticle-specific mechanisms. Zinc oxide (ZnO) NPs are found to induce significant levels of intracellular reactive oxygen species (ROS) to promote mitogenic activity. Generation of a new localized force field through changes in the cytoskeleton organization and an increase in cell density leads to the arrest of CECR. Conversely, epithelial cell clusters exposed to titanium dioxide (TiO2) NPs maintain their CECR directionality but display suppressed rotational speed in an autophagy-dependent manner. Thus, these findings reveal that nanoparticles can actively hijack the nano-adaptive responses of epithelial cells to disrupt the fundamental mechanics of cooperation and communication in a collective setting.

A chemical inhibitor of IST1-CHMP1B interaction impairs endosomal recycling and induces noncanonical LC3 lipidation

The endosomal sorting complex required for transport (ESCRT) machinery constitutes multisubunit protein complexes that play an essential role in membrane remodeling and trafficking. ESCRTs regulate a wide array of cellular processes, including cytokinetic abscission, cargo sorting into multivesicular bodies (MVBs), membrane repair, and autophagy. Given the versatile functionality of ESCRTs, and the intricate organizational structure of the ESCRT machinery, the targeted modulation of distinct ESCRT complexes is considerably challenging. This study presents a pseudonatural product targeting IST1-CHMP1B within the ESCRT-III complexes. The compound specifically disrupts the interaction between IST1 and CHMP1B, thereby inhibiting the formation of IST1-CHMP1B copolymers essential for normal-topology membrane scission events. While the compound has no impact on cytokinesis, MVB sorting, or biogenesis of extracellular vesicles, it rapidly inhibits transferrin receptor recycling in cells, resulting in the accumulation of transferrin in stalled sorting endosomes. Stalled endosomes become decorated by lipidated LC3, suggesting a link between noncanonical LC3 lipidation and inhibition of the IST1-CHMP1B complex.

Potential therapeutic targets of the JAK2/STAT3 signaling pathway in triple-negative breast cancer

Triple-negative breast cancer (TNBC) poses a significant clinical challenge due to its propensity for metastasis and poor prognosis. TNBC evades the body's immune system recognition and attack through various mechanisms, including the Janus Kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) signaling pathway. This pathway, characterized by heightened activity in numerous solid tumors, exhibits pronounced activation in specific TNBC subtypes. Consequently, targeting the JAK2/STAT3 signaling pathway emerges as a promising and precise therapeutic strategy for TNBC. The signal transduction cascade of the JAK2/STAT3 pathway predominantly involves receptor tyrosine kinases, the tyrosine kinase JAK2, and the transcription factor STAT3. Ongoing preclinical studies and clinical research are actively investigating this pathway as a potential therapeutic target for TNBC treatment. This article comprehensively reviews preclinical and clinical investigations into TNBC treatment by targeting the JAK2/STAT3 signaling pathway using small molecule compounds. The review explores the role of the JAK2/STAT3 pathway in TNBC therapeutics, evaluating the benefits and limitations of active inhibitors and proteolysis-targeting chimeras in TNBC treatment. The aim is to facilitate the development of novel small-molecule compounds that target TNBC effectively. Ultimately, this work seeks to contribute to enhancing therapeutic efficacy for patients with TNBC.

TMED2 promotes glioma tumorigenesis by being involved in EGFR recycling transport

Aberrant epidermal growth factor receptor (EGFR) signaling is the core signaling commonly activated in glioma. The transmembrane emp24 protein transport domain protein 2 (TMED2) interacts with cargo proteins involved in protein sorting and transport between endoplasmic reticulum (ER) and Golgi apparatus. In this study, we found the correlation between TMED2 with glioma progression and EGFR signaling through database analysis. Moreover, we demonstrated that TMED2 is essential for glioma cell proliferation, migration, and invasion at the cellular levels, as well as tumor formation in mouse models, underscoring its significance in the pathobiology of gliomas. Mechanistically, TMED2 was found to enhance EGFR-AKT signaling by facilitating EGFR recycling, thereby providing the initial evidence of TMED2's involvement in the membrane protein recycling process. In summary, our findings shed light on the roles and underlying mechanisms of TMED2 in the regulation of glioma tumorigenesis and EGFR signaling, suggesting that targeting TMED2 could emerge as a promising therapeutic strategy for gliomas and other tumors associated with aberrant EGFR signaling.

EGFR trafficking: effect of dimerization, dynamics, and mutation

Spontaneous dimerization of EGF receptors (EGFR) and dysregulation of EGFR signaling has been associated with the development of different cancers. Under normal physiological conditions and to maintain homeostatic cell growth, once EGFR signaling occurs, it needs to be attenuated. Activated EGFRs are rapidly internalized, sorted through early endosomes, and ultimately degraded in lysosomes by a process generally known as receptor down-regulation. Through alterations to EGFR trafficking, tumors develop resistance to current treatment strategies, thus highlighting the necessity for combination treatment strategies that target EGFR trafficking. This review covers EGFR structure, trafficking, and altered surface expression of EGFR receptors in cancer, with a focus on how therapy targeting EGFR trafficking may aid tyrosine kinase inhibitor treatment of cancer.

Betulinic acid in the treatment of breast cancer: Application and mechanism progress

Betulinic acid (BA) is a pentacyclic triterpene compound, which can be obtained by separation, chemical synthesis and biotransformation. BA has excellent biological activities, especially its role in the treatment of breast cancer deserves attention. Its mechanisms mainly include inducing mitochondrial oxidative stress, regulating specific protein (Sp) transcription factors, inhibiting breast cancer metastasis, inhibiting glucose metabolism and NF-κB pathway. In addition, BA can also increase the sensitivity of breast cancer cells to other chemotherapy drugs such as paclitaxel and reduce its toxic side effects. This article reviews the application and possible mechanism of BA in the treatment of breast cancer.

Targeting the Epidermal Growth Factor Receptor with Molecular Degraders: State-of-the-Art and Future Opportunities

Epidermal growth factor receptor (EGFR) is an oncogenic drug target and plays a critical role in several cellular functions including cancer cell growth, survival, proliferation, differentiation, and motility. Several small-molecule tyrosine kinase inhibitors (TKIs) and monoclonal antibodies (mAbs) have been approved for targeting intracellular and extracellular domains of EGFR, respectively. However, cancer heterogeneity, mutations in the catalytic domain of EGFR, and persistent drug resistance limited their use. Different novel modalities are gaining a position in the limelight of anti-EGFR therapeutics to overcome such limitations. The current perspective reflects upon newer modalities, importantly the molecular degraders such as PROTACs, LYTACs, AUTECs, and ATTECs, etc., beginning with a snapshot of traditional and existing anti-EGFR therapies including small molecule inhibitors, mAbs, and antibody drug conjugates (ADCs). Further, a special emphasis has been made on the design, synthesis, successful applications, state-of-the-art, and emerging future opportunities of each discussed modality.

Energy metabolism pathways in breast cancer progression: The reprogramming, crosstalk, and potential therapeutic targets

Breast cancer (BC) is a malignant tumor that seriously endangers health in women. BC, like other cancers, is accompanied by metabolic reprogramming. Among energy metabolism-related pathways, BC exhibits enhanced glycolysis, tricarboxylic acid (TCA) cycle, pentose phosphate pathway (PPP), glutamate metabolism, and fatty acid metabolism activities. These pathways facilitate the proliferation, growth and migration of BC cells. The progression of BC is closely related to the alterations in the activity or expression level of several metabolic enzymes, which are regulated by the intrinsic factors such as the key signaling and transcription factors. The metabolic reprogramming in the progression of BC is attributed to the aberrant expression of the signaling and transcription factors associated with the energy metabolism pathways. Understanding the metabolic mechanisms underlying the development of BC will provide a druggable potential for BC treatment and drug discovery.

Control of cell metabolism by the epidermal growth factor receptor

The epidermal growth factor receptor (EGFR) triggers the activation of many intracellular signals that control cell proliferation, growth, survival, migration, and differentiation. Given its wide expression, EGFR has many functions in development and tissue homeostasis. Some of the cellular outcomes of EGFR signaling involve alterations of specific aspects of cellular metabolism, and alterations of cell metabolism are emerging as driving influences in many physiological and pathophysiological contexts. Here we review the mechanisms by which EGFR regulates cell metabolism, including by modulation of gene expression and protein function leading to control of glucose uptake, glycolysis, biosynthetic pathways branching from glucose metabolism, amino acid metabolism, lipogenesis, and mitochondrial function. We further examine how this regulation of cell metabolism by EGFR may contribute to cell proliferation and differentiation and how EGFR-driven control of metabolism can impact certain diseases and therapy outcomes.

Molecular Research and Treatment of Breast Cancer

Breast cancer is the leading cause of cancer-related deaths in the female population [...]

Dihydroconiferyl Ferulate Isolated from Dendropanax morbiferus H.Lév. Suppresses Stemness of Breast Cancer Cells via Nuclear EGFR/c-Myc Signaling

Breast cancer is the leading cause of global cancer incidence and breast cancer stem cells (BCSCs) have been identified as the target to overcome breast cancer in patients. In this study, we purified a BCSC inhibitor from Dendropanax morbiferus H.Lév. leaves through several open column and high-performance liquid chromatography via activity-based purification. The purified cancer stem cell (CSC) inhibitor was identified as dihydroconiferyl ferulate using nuclear magnetic resonance and mass spectrometry. Dihydroconiferyl ferulate inhibited the proliferation and mammosphere formation of breast cancer cells and reduced the population of CD44^high/CD24^low cells. Dihydroconiferyl ferulate also induced apoptosis, inhibited the growth of mammospheres and reduced the level of total and nuclear EGFR protein. It suppressed the EGFR levels, the interaction of Stat3 with EGFR, and c-Myc protein levels. Our findings show that dihydroconiferyl ferulate reduced the level of nuclear epidermal growth factor receptor (EGFR) and induced apoptosis of BCSCs through nEGFR/Stat3-dependent c-Myc deregulation. Dihydroconiferyl ferulate exhibits potential as an anti-CSC agent through nEGFR/Stat3/c-Myc signaling.

Targeting regulated cell death (RCD) with small-molecule compounds in triple-negative breast cancer: a revisited perspective from molecular mechanisms to targeted therapies

Triple-negative breast cancer (TNBC) is a subtype of human breast cancer with one of the worst prognoses, with no targeted therapeutic strategies currently available. Regulated cell death (RCD), also known as programmed cell death (PCD), has been widely reported to have numerous links to the progression and therapy of many types of human cancer. Of note, RCD can be divided into numerous different subroutines, including autophagy-dependent cell death, apoptosis, mitotic catastrophe, necroptosis, ferroptosis, pyroptosis and anoikis. More recently, targeting the subroutines of RCD with small-molecule compounds has been emerging as a promising therapeutic strategy, which has rapidly progressed in the treatment of TNBC. Therefore, in this review, we focus on summarizing the molecular mechanisms of the above-mentioned seven major RCD subroutines related to TNBC and the latest progress of small-molecule compounds targeting different RCD subroutines. Moreover, we further discuss the combined strategies of one drug (e.g., narciclasine) or more drugs (e.g., torin-1 combined with chloroquine) to achieve the therapeutic potential on TNBC by regulating RCD subroutines. More importantly, we demonstrate several small-molecule compounds (e.g., ONC201 and NCT03733119) by targeting the subroutines of RCD in TNBC clinical trials. Taken together, these findings will provide a clue on illuminating more actionable low-hanging-fruit druggable targets and candidate small-molecule drugs for potential RCD-related TNBC therapies.