Bufalin inhibits human diffuse large B-cell lymphoma tumorigenesis by inducing cell death through the Ca2+/NFATC1/cMYC pathway

Bufalin reprograms erythrocyte lifespan through p38 MAPK and Rac1 GTPase

Ample evidence indicates that bufalin (BFN), a cardiotonic steroid in Bufo toad toxin, possesses a potent anticancer activity mainly by stimulating apoptosis in cancer cells. Human red blood cells (RBCs) undergo eryptosis which contributes to a plethora of pathological conditions. No reports, however, have examined the potential toxicity of BFN to RBCs. This study aims to characterize the biochemical mechanisms governing the influence of BFN on the physiology and lifespan of RBCs. Isolated RBCs from healthy volunteers were exposed to anticancer concentrations of commercially available BFN from the skin of Bufo gargarizans (10-200 μM) for 24 h at 37 °C. Photometric assays were used to estimate hemolysis and hemolytic markers, and flow cytometry was used to detect eryptotic markers. Phosphatidylserine externalization was captured by fluorescein isothiocyante-labeled annexin V, cellular dimensions by light scatter patterns, and intracellular Ca2+ and reactive oxygen species (ROS) by fluorogenic dyes Fluo4/AM and 2',7'-dichlorodihydrofluorescein diacetate (H2DCFDA), respectively. BFN caused Ca2+-independent hemolysis and release of LDH, AST, CK, and K+, and increased annexin V-bound cells, cytosolic Ca2+, cell shrinkage, and ROS levels. BFN also disrupted Na+ and Mg2+ trafficking, and was sensitive to PEG 8000, sucrose, SB203580, and NSC 23766. In whole blood, BFN depleted hemoglobin stores, increased fragmented RBCs, and was selectively toxic to reticulocytes, lymphocytes, and platelets. In conclusion, BFN elicits premature RBC death, subject to regulation by p38 MAPK and Rac1 GTPase, and is detrimental to other peripheral blood cells. Altogether, these novel findings prompt cautious consideration of the toxin in anticancer therapy.

Human bone marrow-derived mesenchymal stem overexpressing microRNA-124-3p inhibit DLBCL progression by downregulating the NFATc1/cMYC pathway

BACKGROUND

Exosomes play important roles in intercellular communication by delivering microRNAs (miRNAs) that mediate tumor initiation and development, including those in diffuse large B cell lymphoma (DLBCL). To date, however, limited studies on the inhibitory effect of exosomes derived from human bone marrow mesenchymal stem cells (hBMSCs) on DLBCL progression have been reported. Therefore, this study aimed to investigate the role of hBMSC exosomes carrying microRNA-124-3p in the development of DLBCL.

METHODS

Microarray-based expression analysis was adopted to identify differentially expressed genes and regulatory miRNAs, which revealed the candidate NFATc1. Next, the binding affinity between miR-124-3p and NFATc1 was detected by luciferase activity assays. The mechanism underlying NFATc1 regulation was investigated using lentiviral transfections. Subsequently, DLBCL cells were cocultured with exosomes derived from hBMSCs transfected with a miR-124-3p mimic or control. Proliferation and apoptosis were measured in vitro. Finally, the effects of hBMSC-miR-124-3p on tumor growth were investigated in vivo.

RESULTS

MiR-124-3p was expressed at low levels, while NFATc1 was highly expressed in DLBCL cells. MiR-124-3p specifically targeted and negatively regulated the expression of NFATc1 in DLBCL cells, upregulated miR-124-3p-inhibited DLBCL cell proliferation and promoted apoptosis. The miR-124-3p derived from hBMSCs inhibits tumor growth both in vivo and in vitro via downregulation of the NFATc1/cMYC pathway.

CONCLUSION

Human bone marrow-derived mesenchymal stem cell overexpressing microRNA-124-3p represses the development of DLBCL through the downregulation of NFATc1.

Bufalin-Mediated Regulation of Cell Signaling Pathways in Different Cancers: Spotlight on JAK/STAT, Wnt/β-Catenin, mTOR, TRAIL/TRAIL-R, and Non-Coding RNAs

The renaissance of research into natural products has unequivocally and paradigmatically shifted our knowledge about the significant role of natural products in cancer chemoprevention. Bufalin is a pharmacologically active molecule isolated from the skin of the toad Bufo gargarizans or Bufo melanostictus. Bufalin has characteristically unique properties to regulate multiple molecular targets and can be used to harness multi-targeted therapeutic regimes against different cancers. There is burgeoning evidence related to functional roles of signaling cascades in carcinogenesis and metastasis. Bufalin has been reported to regulate pleiotropically a myriad of signal transduction cascades in various cancers. Importantly, bufalin mechanistically regulated JAK/STAT, Wnt/β-Catenin, mTOR, TRAIL/TRAIL-R, EGFR, and c-MET pathways. Furthermore, bufalin-mediated modulation of non-coding RNAs in different cancers has also started to gain tremendous momentum. Similarly, bufalin-mediated targeting of tumor microenvironments and tumor macrophages is an area of exciting research and we have only started to scratch the surface of the complicated nature of molecular oncology. Cell culture studies and animal models provide proof-of-concept for the impetus role of bufalin in the inhibition of carcinogenesis and metastasis. Bufalin-related clinical studies are insufficient and interdisciplinary researchers require detailed analysis of the existing knowledge gaps.

Proliferation, apoptosis and invasion of human lung cancer cells are associated with NFATc1

The expression of nuclear factor of activated T cells c1 (NFATc1) is closely associated with the progression of numerous types of cancer. When NFATc1 expression becomes dysregulated in some types of cancer, this alteration can promote malignant transformation and thereby progression of cancer. NFATc1 expression has been demonstrated to be upregulated in lung cancer cells. This suggests that knockdown of NFATc1 in lung cancer cells may be a therapeutic marker for the treatment of cancer. In the present study, the effects of NFATc1 on the proliferation, apoptosis, invasion and migration of NCI-H1299 and A549 lung cancer cell lines were explored. Lentivirus infection was used to establish a cell model of NFATc1 knockdown in A549 and NCI-H1299 lung cancer cells. Reverse transcription-quantitative PCR was subsequently performed to detect NFATc1 expression in these human lung cancer cells. MTT, wound healing, colony formation and Transwell invasion assays, and flow cytometry were then performed to measure the proliferation, invasion, apoptosis and cell cycle of the cells. Finally, western blot analysis was performed to investigate the mechanism underlying the involvement of NFATc1 in these processes. NFATc1 knockdown was found to significantly inhibit the proliferation, clone formation, migration and invasion of the cells. Furthermore, the cell cycle was arrested at the G₁ phase and the expression levels of the target proteins located downstream in the signaling pathway, namely CDK4, c-Myc, ERK, p38 and N-cadherin, were decreased. Following NFATc1 knockdown, the percentages of apoptotic cells were increased, and the expression levels of Bax, cleaved caspase-3 and E-cadherin were also increased. Taken together, the results of the present study suggested that NFATc1 serves an oncogenic role in lung cancer. In terms of the underlying mechanism, NFATc1 promoted the proliferation of lung cancer cells by inhibiting the MAPK and epithelial-to-mesenchymal transition signaling pathways, suggesting that NFATc1 may be a novel target for therapeutic intervention for the treatment of lung cancer.

Bufalin for an innovative therapeutic approach against cancer

Bufalin is an endogenous cardiotonic steroid, first discovered in toad venom but also found in the plasma of healthy humans, with anti-tumour activities in different cancer types. The current review is focused on its mechanisms of action and highlights its very large spectrum of effects both in vitro and in vivo. All leads to the conclusion that bufalin mediates its effects by affecting all the hallmarks of cancer and seems restricted to cancer cells avoiding side effects. Bufalin decreases cancer cell proliferation by acting on the cell cycle and inducing different mechanisms of cell death including apoptosis, necroptosis, autophagy and senescence. Bufalin also moderates metastasis formation by blocking migration and invasion as well as angiogenesis and by inducing a phenotype switch towards differentiation and decreasing cancer cell stemness. Regarding its various mechanisms of action in cancer cells, bufalin blocks overactivated signalling pathways and modifies cell metabolism. Moreover, bufalin gained lately a huge interest in the field of drug resistance by both reversing various drug resistance mechanisms and affecting the immune microenvironment. Together, these data support bufalin as a quite promising new anti-cancer drug candidate.

Salvia chinensis Benth Inhibits Triple-Negative Breast Cancer Progression by Inducing the DNA Damage Pathway

Objective

Triple-negative breast cancer (TNBC) is distinguished by early recurrence and metastases, a high proclivity for treatment resistance, and a lack of targeted medicines, highlighting the importance of developing innovative therapeutic techniques. Salvia chinensis Benth (SCH) has been widely studied for its anticancer properties in a variety of cancers. However, its significance in TNBC treatment is rarely discussed. Our study investigated the anticancer effect of SCH on TNBC and the underlying mechanisms.

Methods

First, we used clonogenic, cell viability, flow cytometry, and Transwell assays to assess the effect of SCH on TNBC. Bioinformatic studies, especially network pharmacology-based analysis and RNA sequencing analysis, were performed to investigate the constituents of SCH and its molecular mechanisms in the suppression of TNBC. High-performance liquid chromatography and thin-layer chromatography were used to identify two major components, quercetin and β-sitosterol. Then, we discovered the synergistic cytotoxicity of quercetin and β-sitosterol and assessed their synergistic prevention of cell migration and invasion. Breast cancer xenografts were also created using MDA-MB-231 cells to test the synergistic therapeutic impact of quercetin and β-sitosterol on TNBC in vivo. The impact on the DNA damage and repair pathways was investigated using the comet assay and Western blot analysis.

Results

Our findings showed that SCH decreased TNBC cell growth, migration, and invasion while also inducing cell death. We identified quercetin and β-sitosterol as the core active components of SCH based on a network pharmacology study. According to RNA sequencing research, the p53 signaling pathway is also regarded as a critical biological mechanism of SCH treatment. The comet assay consistently showed that SCH significantly increased DNA damage in TNBC cells. Our in vivo and in vitro data revealed that the combination of quercetin and β-sitosterol induced synergistic cytotoxicity and DNA damage in TNBC cells. In particular, SCH particularly blocked the inter-strand cross-link repair mechanism and the double-strand breach repair caused by the homologous recombination pathway, in addition to inducing DNA damage. Treatment with quercetin and β-sitosterol produced similar outcomes.

Conclusion

The current study provides novel insight into the previously unknown therapeutic potential of SCH as a DNA-damaging agent in TNBC.

Resibufogenin Targets the ATP1A1 Signaling Cascade to Induce G2/M Phase Arrest and Inhibit Invasion in Glioma

Resibufogenin (RB) is a major active ingredient in the traditional Chinese medicine Chansu and has garnered considerable attention for its efficacy in the treatment of cancer. However, the anticancer effects and underlying mechanisms of RB on glioblastoma (GBM) remain unknown. Here, we found that RB induced G2/M phase arrest and inhibited invasion in a primary GBM cell line, P3#GBM, and two GBM cell lines, U251 and A172. Subsequently, we demonstrated that RB-induced G2/M phase arrest occurred through downregulation of CDC25C and upregulation of p21, which was caused by activation of the MAPK/ERK pathway, and that RB inhibited GBM invasion by elevating intercellular Ca²⁺ to suppress the Src/FAK/Paxillin focal adhesion pathway. Intriguingly, we confirmed that upon RB binding to ATP1A1, Na⁺-K⁺-ATPase was activated as a receptor and then triggered the intracellular MAPK/ERK pathway and Ca²⁺-mediated Src/FAK/Paxillin focal adhesion pathway, which led to G2/M phase arrest and inhibited the invasion of GBM cells. Taken together, our findings reveal the antitumor mechanism of RB by targeting the ATP1A1 signaling cascade and two key signaling pathways and highlight the potential of RB as a new class of promising anticancer agents.