Diterpenoid natural compound C4 (Crassin) exerts cytostatic effects on triple-negative breast cancer cells via a pathway involving reactive oxygen species

Ferroptosis: the emerging player in remodeling triple-negative breast cancer

Triple-negative breast cancer (TNBC) is a highly heterogeneous breast tumor type that is highly malignant, invasive, and highly recurrent. Ferroptosis is a unique mode of programmed cell death (PCD) at the morphological, physiological, and molecular levels, mainly characterized by cell death induced by iron-dependent accumulation of lipid peroxides, which plays a substantial role in a variety of diseases, including tumors and inflammatory diseases. TNBC cells have been reported to display a peculiar equilibrium metabolic profile of iron and glutathione, which may increase the sensitivity of TNBC to ferroptosis. TNBC possesses a higher sensitivity to ferroptosis than other breast cancer types. Ferroptosis also occurred between immune cells and tumor cells, suggesting that regulating ferroptosis may remodel TNBC by modulating the immune response. Many ferroptosis-related genes or molecules have characteristic expression patterns and are expected to be diagnostic targets for TNBC. Besides, therapeutic strategies based on ferroptosis, including the isolation and extraction of natural drugs and the use of ferroptosis inducers, are urgent for TNBC personalized treatment. Thus, this review will explore the contribution of ferroptosis in TNBC progression, diagnosis, and treatment, to provide novel perspectives and therapeutic strategies for TNBC management.

The single-atom iron nanozyme mimicking peroxidase remodels energy metabolism and tumor immune landscape for synergistic chemodynamic therapy and photothermal therapy of triple-negative breast cancer

Chemotherapy, as one main strategy to relieve tumor progression, has a weak effect on triple-negative breast cancer (TNBC) chest wall metastasis. The development of near-infrared (NIR) light-responsive nanomaterials for chemodynamic therapy (CDT) and photothermal therapy (PTT) is a promising platform but still challenging in biomedicine. This study reports a peroxidase mimicking nanozyme (Fe-N-C SAzyme) against TNBC by CDT and PTT. Fe-N-C SAzyme generated reactive oxygen species (ROS) by decomposing H2O2 into hydroxyl radicals (•OH) and also induced light-to-heat conversion under the exposure of 808 nm laser irradiation. With these biological characteristics, the obtained Fe-N-C SAzymes displayed enhanced cell cytotoxicity and inhibition of cancer cell proliferation both in vitro and in vivo at a low dose of nanoagent and a moderate NIR laser power density. Besides, Fe-N-C nanoagent with its excellent ROS generation brought metabolic reprogramming of elevated glycolysis in tumor cells. In vivo experiments, when combined with PTT, the enhanced antitumor effect was found by the elimination of M-MDSC in tumor microenvironment. Fe-N-C SAzymes can serve as a new synergistic CDT and PTT nanoagent to simultaneously reprogram tumor metabolism and tumor microenvironment. It will provide prospects for chemodynamic/photothermal combined cancer therapy for TNBC chest wall metastasis based on the use of a single nanosystem.

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.

The Regulatory Effects and the Signaling Pathways of Natural Bioactive Compounds on Ferroptosis

Natural bioactive compounds abundantly presented in foods and medicinal plants have recently received a remarkable attention because of their various biological activities and minimal toxicity. In recent years, many natural compounds appear to offer significant effects in the regulation of ferroptosis. Ferroptosis is the forefront of international scientific research which has been exponential growth since the term was coined. This type of regulated cell death is driven by iron-dependent phospholipid peroxidation. Recent studies have shown that numerous organ injuries and pathophysiological processes of many diseases are driven by ferroptosis, such as cancer, arteriosclerosis, neurodegenerative disease, diabetes, ischemia-reperfusion injury and acute renal failure. It is reported that the initiation and inhibition of ferroptosis plays a pivotal role in lipid peroxidation, organ damage, neurodegeneration and cancer growth and progression. Recently, many natural phytochemicals extracted from edible plants have been demonstrated to be novel ferroptosis regulators and have the potential to treat ferroptosis-related diseases. This review provides an updated overview on the role of natural bioactive compounds and the potential signaling pathways in the regulation of ferroptosis.

Lycorine inhibits cell proliferation, migration and invasion, and primarily exerts in vitro cytostatic effects in human colorectal cancer via activating the ROS/p38 and AKT signaling pathways

Colorectal cancer (CRC) is a life‑threatening malignant tumor of the digestive tract. Diverse gene mutations and complicated alterations to the signaling pathways in CRC lead to heterogeneity in response to chemotherapy. Moreover, anticancer drugs for CRC chemotherapy are limited due to adverse events. Therefore, developing more effective, tolerable and safe drugs for the treatment of CRC is important. The present study aimed to investigate the effect of lycorine on human CRC cell proliferation, migration, invasion, apoptosis, cell cycle distribution, as well as the underlying molecular mechanism. The crystal violet staining and MTT assay results demonstrated that lycorine suppressed cell proliferation in a dose‑ and time‑dependent manner in the three CRC cell lines, HCT116, LoVo and SW480. Similarly, verified by performing wound healing and Transwell assays, lycorine significantly inhibited HCT116 and LoVo cell migration and invasion in vitro compared with the control group. In LoVo cells, the protein expression levels of matrix metallopeptidases, snail family transcriptional repressor 1, Vimentin and N‑cadherin were significantly downregulated, whereas the protein expression levels of E‑cadherin were significantly upregulated by lycorine treatment compared with the control group. The Hoechst 33258 staining and flow cytometry assay results indicated that lycorine mediated its cytostatic effect on CRC cells potentially via inducing cell cycle arrest, but not apoptosis. Compared with the control group, lycorine significantly induced HCT116 cell cycle arrest at the G2/M phase, but significantly induced LoVo cell cycle arrest at the S and G2/M phases. Furthermore, lycorine significantly downregulated the protein expression levels of cyclin D1 and cyclin E1, but significantly increased p21 and Smad4 protein expression levels in HCT116 and LoVo cells compared with the control group. The intracellular reactive oxygen species (ROS) measurement results also indicated that compared with the control group, lycorine significantly induced ROS accumulation, and increased phosphorylated‑p38 expression levels and AKT phosphorylation. Collectively, the present study suggested that lycorine might induce cell cycle arrest and exert cytostatic effects potentially via activating ROS/p38 and AKT signaling pathways in CRC cells.

Holo-lactoferrin: the link between ferroptosis and radiotherapy in triple-negative breast cancer

Rationale: Iron-saturated Lf (Holo-Lactoferrin, Holo-Lf) exhibits a superior anticancer property than low iron-saturated Lf (Apo-Lf). Ferroptosis is an iron-dependent cell death characterized by the accumulation of lipid peroxidation products and lethal reactive oxygen species (ROS). Radiotherapy also exerts its therapeutic effect through ROS.

Methods: The effect of different iron-saturated Lf on ferroptosis and radiotherapy were tested on triple-negative breast cancer (TNBC) cell line MDA-MB-231 and non-TNBC cell line MCF-7.

Results: Holo-Lf significantly increased the total iron content, promoted ROS generation, increased lipid peroxidation end product, malondialdehyde (MDA), and enhanced ferroptosis of MDA-MB-231 cells. By contrast, Apo-Lf upregulated SLC7a11 expression, increased GSH generation and inhibited ferroptosis of MDA-MB-231 cells. However, non-TNBC MCF-7 cells were resistant to Holo-Lf-induced ferroptosis because MCF-7 cells have a higher redox balance capacity than MDA-MB-231 cells. More importantly, Holo-Lf downregulated HIF-1α expression, ameliorated the hypoxia microenvironment in subcutaneous MDA-MB-231 tumors, and promoted radiation-induced DNA damage to hypoxic MDA-MB-231 cells. Finally, the efficacy of radiotherapy to MDA-MB-231 tumors was enhanced by Holo-Lf.

Conclusion: Holo-Lf could induce ferroptosis in MDA-MB-231 cells and sensitize MDA-MB-231 tumors to radiotherapy.

Neuroprotective effects of glucomoringin-isothiocyanate against H2O2-Induced cytotoxicity in neuroblastoma (SH-SY5Y) cells

Neurodegenerative diseases (NDDs) are pathological conditions characterised by progressive damage of neuronal cells leading to eventual loss of structure and function of the cells. Due to implication of multi-systemic complexities of signalling pathways in NDDs, the causes and preventive mechanisms are not clearly delineated. The study was designed to investigate the potential signalling pathways involved in neuroprotective activities of purely isolated glucomoringin isothiocyanate (GMG-ITC) against H₂O₂-induced cytotoxicity in neuroblastoma (SH-SY5Y) cells. GMG-ITC was isolated from Moringa oleifera seeds, and confirmed with NMR and LC-MS based methods. Gene expression analysis of phase II detoxifying markers revealed significant increase in the expression of all the genes involved, due to GMG-ITC pre-treatment. GMG-ITC also caused significant decreased in the expression of NF-kB, BACE1, APP and increased the expressions of IkB and MAPT tau genes in the differentiated cells as confirmed by multiplex genetic system analysis. The effect was reflected on the expressed proteins in the differentiated cells, where GMG-ITC caused increased in expression level of Nrf2, SOD-1, NQO1, p52 and c-Rel of nuclear factor erythroid factor 2 (Nrf2) and nuclear factor kappa-B (NF-kB) pathways respectively. The findings revealed the potential of GMG-ITC to abrogate oxidative stress-induced neurodegeneration through Nrf2 and NF-kB signalling pathways.

Cytotoxicity of ungeremine towards multi-factorial drug resistant cancer cells and induction of apoptosis, ferroptosis, necroptosis and autophagy

BACKGROUND

Successful cancer chemotherapy is hampered by resistance of cancer cells to established anticancer drugs. Numerous natural products reveal cytotoxicity towards tumor cells.

PURPOSE

The present study was aimed to determine the cytotoxicity of a betaine-type alkaloid, ungeremine, towards 9 cancer cell lines including various sensitive and drug-resistant phenotypes. The mode of action of this compound was further investigated.

METHODS

The cytotoxicity, ferroptotic and necroptotic cell death were determined by the resazurin reduction assay. Caspase activation was evaluated using the caspase-Glo assay. Flow cytometry was applied for the analysis of cell cycle analysis (PI staining), apoptosis (annexin V/PI staining), mitochondrial membrane potential (MMP) (JC-1) and reactive oxygen species (ROS) (H₂DCFH-DA). Apoptotic, necroptotic and autophagic markers were determined by Western blotting. CCRF-CEM leukemia cells were used for all mechanistic studies.

RESULTS

Ungeremine displayed cytotoxic activity towards the 9 cancer cell lines tested, including drug-sensitive and MDR phenotypes. The IC₅₀values obtained varied from 3.67 µM (in MDA-MB-231-BCRP breast carcinoma cells) to 75.24 µM (against in CEM/ADR5000 leukemia cells) for ungeremine and from 0.02 µM (against CCRF-CEM cells) to 122.96 µM (against CEM/ADR5000 cells) for doxorubicin (control drug). Ungeremine induced ferroptosis, necroptosis, autophagy as well as apoptosis mediated by caspase activation, MMP alteration and increase ROS production.

CONCLUSION

The present investigation showed that ungeremine is a promising cytotoxic compoundthat could be further explored in the future to develop new anticancer drugs to fight sensitive and resistant phenotypes.

RPLP1 promotes tumor metastasis and is associated with a poor prognosis in triple-negative breast cancer patients

Background

Cancer metastasis is the major reason for cancer related deaths, and the mechanism of cancer metastasis still unclear. RPLP1, a member of a group of proteins known as ribosomal proteins, is associated with tumorigenesis and primary cell immortalization and is involved in cellular transformation. However, the expression and potential function of RPLP1 in TNBC remain unclear.

Methods

The expression of RPLP1 in TNBC tissues and cell lines were detected with Real-Time PCR and western blotting. 81 cases of TNBC tissue samples and adjacent non-tumor tissue samples were tested by immunochemistry to determine the correlation between the RPLP1 expression and clinicopathological characteristics. In vitro, we determined the role and mechanistic pathways of RPLP1 in tumor metastasis in TNBC cell lines.

Results

In this study, we detected high levels of RPLP1 expression in TNBC samples and cell lines. RPLP1 is upregulated in triple-negative breast cancer (TNBC) tissues and cells, and high expression levels correlate with an increased risk of recurrence and metastasis. Furthermore, high RPLP1 expression was associated with a poor prognosis and was an independent prognostic marker for TNBC. In RPLP1-induced cancer metastasis, RPLP1 may increase cancer cell invasion, which is likely the result of its effect on the cancer cell epithelial-mesenchymal transition.

Conclusions

Altogether, our findings indicate RPLP1 is a poor prognostic potential biomarker and anti-metastasis candidate therapeutic target in triple-negative breast cancer.

Low power blue LED exposure increases effects of doxorubicin on MDA-MB-231 breast cancer cells

Patients with triple negative breast cancer can develop side effects as a result of chemotherapy. Photodynamic therapy may reduce these side effects if the chemotherapy agent could also act as a photosensitizer. Thus, the aim of this work was to evaluate cytotoxicity and reactive oxygen species production induced by doxorubicin and low power blue LED in breast cancer cultures. Cell viability and reactive oxygen species (ROS) in MDA-MB-231 cultures were evaluated in response to different doxorubicin concentrations and blue LED fluences. Compared with control, cell cultures only incubated with doxorubicin at 25 nM showed 23% of cell viability reduction while its combination with blue LED at 640 J/cm² reduced 40% of cell viability after 24 h. After 48 h, reduction of cell viability raises to 40% in cell cultures only incubated with doxorubicin and 55% when combined with blue LED. Evaluation 30 min after treatment showed that cells incubated with doxorubicin and exposed to blue LED generated 22% more ROS than controls. Those results show that incubation with doxorubicin combined with exposure to low power blue LED is more cytotoxic and more effective to increase ROS levels in MDA-MB-231 cultures than incubation with doxorubicin alone.