melitten and Lung-Neoplasms

Melittin, a naturally occurring polypeptide found in bee venom, has been recognized for its potential anti-tumor effects, particularly in the context of lung cancer. Our previous study focused on its impact on human lung adenocarcinoma cells A549, revealing that melittin induces intracellular reactive oxygen species (ROS) burst and oxidative damage, resulting in cell death. Considering the significant role of mitochondria in maintaining intracellular redox levels and ROS, we further examined the involvement of mitochondrial damage in melittin-induced apoptosis in lung cancer cells. Our findings demonstrated that melittin caused changes in mitochondrial membrane potential (MMP), triggered mitochondrial ROS burst (Figure 1), and activated the mitochondria-related apoptosis pathway Bax/Bcl-2 by directly targeting mitochondria in A549 cells (Figure 2). Further, we infected A549 cells using a lentivirus that can express melittin-Myc and confirmed that melittin can directly target binding to mitochondria, causing the biological effects described above (Figure 2). Notably, melittin induced mitochondrial damage while inhibiting autophagy, resulting in abnormal degradation of damaged mitochondria (Figure 5). To summarize, our study unveils that melittin targets mitochondria, causing mitochondrial damage, and inhibits the autophagy-lysosomal degradation pathway. This process triggers mitoROS burst and ultimately activates the mitochondria-associated Bax/Bcl-2 apoptotic signaling pathways in A549 cells.

Topics: A549 Cells; Apoptosis; bcl-2-Associated X Protein; Humans; Lung Neoplasms; Melitten; Membrane Potential, Mitochondrial; Mitochondria; Mitophagy; Reactive Oxygen Species

Cancer vaccines are viewed as a promising immunotherapy to eradicate malignant tumors and aim to elicit the patients' own tumor-specific immune response against tumor cells. However, few cancer vaccines have been applied due to the low immunogenicity of antigen and invalidation of adjuvant. Herein, we designed a tumor microenvironment (TME) responsive MnO

Topics: Animals; Antigens; Cancer Vaccines; CD8-Positive T-Lymphocytes; Immunity; Immunotherapy; Lung Neoplasms; Manganese Compounds; Melitten; Metal Nanoparticles; Mice; Nanoparticles; Oxides; Tumor Microenvironment

Melittin is a major active peptide component of bee venom that has been demonstrated to show anti-tumor effects. Osteosarcoma is a type of bone tumor with a high degree of malignancy, and metastasis is the main challenge of osteosarcoma therapy. This study aimed to investigate the role of melittin in the lung metastasis of osteosarcoma. 143 B cells were treated with different concentrations of melittin in vitro. Wound-healing and transwell assays were performed to determine the cell migration and invasion potential. Quantitative real-time PCR and Western blot experiments were performed to evaluate the expression levels of Wnt/β-catenin signaling pathway-related factors after treatment with melittin. The orthotopic implantation model and hematoxylin-eosin staining were used to investigate the effect of melittin treatment on tumor formation and lung metastasis. Immunohistochemical staining and Western blot experiments were performed to indicate the melittin-mediated expression changes in Wnt/β-catenin signaling pathway-related factors. The cell migration and invasion potential were observed to be inhibited in a dose-dependent manner upon treatment with melittin. Treatment with medium and high concentrations of melittin attenuated the mRNA and protein expression of LRP5, β-catenin, MMP-2, cyclin D, c-Myc, survivin, MMP-9, and VEGF genes in vitro. Melittin significantly inhibited the growth of tibia xenografts in nude mice and decreased the number of lung metastatic nodules. Consistent with the results observed in vitro, treatment with melittin at medium and high concentrations attenuated the expression of Wnt/β-catenin signaling pathway-related factors in vivo. In vitro, Wnt/β-catenin signaling pathway was involved in Melittin-mediated -migration and invasion potential of 143 B cells. Similarly, as observed in the in vivo experiments, Wnt/β-catenin signaling pathway was also associated with the role of melittin on lung metastasis of osteosarcomas.

Topics: Animals; Bone Neoplasms; Cell Line, Tumor; Cell Movement; Cell Proliferation; Humans; Lung Neoplasms; Melitten; Mice; Mice, Nude; Osteosarcoma; Wnt Signaling Pathway

The purpose of this study was to investigate the anti-cancer effect of melittin on growth, migration, invasion, and apoptosis of non-small-cell lung cancer (NSCLC) cells. This study also explored the potential anti-cancer mechanism of melittin in NSCLC cells. The results demonstrated that melittin suppressed growth, migration, and invasion, and induced apoptosis of NSCLC cells in vitro. Melittin increased pro-apoptotic caspase-3 and Apaf-1 gene expression. Melittin inhibited tumor growth factor (TGF)-β expression and phosphorylated ERK/total ERK (pERK/tERK) in NSCLC cells. However, TGF-β overexpression (pTGF-β) abolished melittin-decreased TGF-β expression and pERK/tERK in NSCLC cells. Treatment with melittin suppressed tumor growth and prolonged mouse survival during the 120-day observation in vivo. Treatment with melittin increased TUNEL-positive cells and decreased expression levels of TGF-β and ERK in tumor tissue compared to the control group. In conclusion, the findings of this study indicated that melittin inhibited growth, migration, and invasion, and induced apoptosis of NSCLC cells through down-regulation of TGF-β-mediated ERK signaling pathway, suggesting melittin may be a promising anti-cancer agent for NSCLC therapy.

Topics: Animals; Apoptosis; Apoptotic Protease-Activating Factor 1; Carcinoma, Non-Small-Cell Lung; Caspase 3; Cell Line, Tumor; Cell Movement; Down-Regulation; Gene Expression Regulation, Neoplastic; Lung Neoplasms; MAP Kinase Signaling System; Melitten; Mice; Neoplasm Invasiveness; Transforming Growth Factor beta

Specific drug delivery to metastatic tumors remains a great challenge for antimetastasis therapy. We herein report a bioengineered macrophage-based delivery system (LD-MDS) that can be preferentially delivered to lung metastases and intelligently transformed into nanovesicles and secondary nanovesicles for antimetastasis therapy. LD-MDS was prepared by anchoring a legumain-specific propeptide of melittin (legM) and cytotoxic soravtansine (DM4) prodrug onto the membrane of living macrophages. LD-MDS is responsively activated by legumain protease and converted into DM4-loaded exosome-like nanovesicles (DENs), facilitating efficient internalization by metastatic 4T1 cancer cells and considerable cell death. Afterward, the damaged 4T1 cells can release secondary nanovesicles and free drug molecules to destroy neighboring cancer cells. In vivo, LD-MDS displays superior targeting efficiency for lung metastatic lesions with diameters less than 100 μm and remarkably inhibits lung metastasis. This study provides a new opportunity to explore endogenous macrophages as living drug delivery vehicles with controlled drug release to target metastatic lung tumors.

Topics: Animals; Antineoplastic Agents; Cell Line, Tumor; Cell Survival; Cysteine Endopeptidases; Drug Carriers; Drug Liberation; Humans; Lung Neoplasms; Macrophages; Maytansine; Melitten; Mice, Nude; Nanoparticles; Neoplasm Metastasis; Prodrugs

Lung cancer accounts for a significant percentage of all cancer‑associated mortalities in men and women, with non‑small cell lung cancer being the most frequently occurring type of lung cancer. Melittin is the principal active component of apitoxin (bee venom) that has been reported to exert anti‑chronic inflammatory and anti‑cancer effects. In the present study, the antitumor effect of melittin was evaluated using in vivo and in vitro analyses. The results demonstrated that melittin significantly inhibited the epidermal growth factor‑induced invasion and migration of non‑small cell lung cancer cells. Subcutaneous injection of melittin at doses of 1 and 10 mg/kg significantly suppressed non‑small cell lung cancer tumor growth by 27 and 61%, respectively. In addition, melittin significantly inhibited the secretion of vascular endothelial growth factor (VEGF) in non‑small cell lung cancer cells. Furthermore, melittin decreased the protein expression of VEGF and hypoxia‑inducible factor 1‑α. Therefore, the antitumor activity of melittin may be associated with the anti‑angiogenic actions of inhibiting the VEGF and hypoxia‑inducible factor signaling pathways.

Topics: A549 Cells; Animals; Antineoplastic Agents; Apoptosis; Carcinoma, Non-Small-Cell Lung; Cell Movement; Cell Survival; Flow Cytometry; Humans; Lung Neoplasms; Male; Melitten; Mice, Inbred BALB C; Mice, Nude; Neoplasm Invasiveness; Vascular Endothelial Growth Factor A; Xenograft Model Antitumor Assays

Cytokine fusion protein that modulates the immune response holds great potential for cancer immunotherapy. IL-2 is an effective treatment against advanced cancers. However, the therapeutic efficacy of IL-2 is limited by severe systemic toxicity. Several mutants recombinant IL-2 can increase antitumor activity and minimize systemic toxicity. Melittin is an attractive anticancer candidate because of its wide-spectrum lytic properties. We previously generated a bifunctional fusion protein melittin-MIL-2, composed of melittin and a mutant IL-2. The melittin-MIL-2 inhibited the growth of human ovarian cancer SKOV3 cells in vitro and in vivo tumor growth. However, whether this antitumor effect could also be used in cancer immunotherapy was unknown. To assess its cancer immunotherapy potential, we further investigated its more effective antitumor immune response and antitumor effect against cancers of different tissue origins in vitro and in vivo.. The specific IL-2 activity of the melittin-MIL-2 fusion protein was tested on the cytokine growth dependent cell line CTLL-2. The cytolytic activity was detected by standard 4-h (51)Cr-release assays. PBMC stimulation in response to the melittin-MIL-2 was determined by IFN-γ release assay. We observed the cancer cell proliferation of different tissue origins by MTT assay. The ability of melittin-MIL-2 to inhibit tumor growth in vivo was evaluated by using human liver (SMMC-7721 cancer cells), lung (A549 cancer cells) and ovarian (SKOV3 cancer cells) cancer xenograft models. To assess the immunity within the tumor microenvironment, the level of some cytokines including IFN-γ, TNF-α, IL-12 and IL-4 was analyzed by ELISA. We injected the MDA-MB-231 cells and the melittin-MIL-2 into mice, and the anti-metastatic effect was examined by counting nodules in the lung.. The melittin-MIL-2 was more effective in inducing T cell and NK-cell cytotoxicity. The fusion protein significantly increased IFN-γ production in PBMCs. In vitro, the melittin-MIL-2 mediated immune cells killing or directly killed the cancer cell lines of different tissue origins. In vivo, the fusion protein exhibited stronger inhibition on the growth of transplanted human tumors compared to rIL-2. The melittin-MIL-2 treatment promoted the IFN-γ secretion in tumor tissues and decreased the immunosuppressive cells in vivo. Furthermore, the fusion protein reduced lung metastasis of breast cancer.. This study provides the evidence that the melittin-MIL-2 can produce stronger immune stimulation and antitumor effects, and the fusion protein is a potent candidate for cancer immunotherapy.

Topics: Animals; Antineoplastic Agents; Cell Line, Tumor; Cell Proliferation; Cellular Microenvironment; Cytotoxicity, Immunologic; Disease Models, Animal; Female; Humans; Immunomodulation; Immunotherapy; Interferon-gamma; Lung Neoplasms; Lymphocyte Activation; Melitten; Mice, Inbred BALB C; Mutant Proteins; Neoplasms; Recombinant Fusion Proteins

In order to elucidate the structure-antibiotic activity relationships of the peptides, the three-dimensional structures of two hybrid peptides, CA(1-8) - MA(1-12) and CA(1-8) - ME(1-12) in trifluoroethanol-containing aqueous solution were investigated by NMR spectroscopy. Both CA(1-8) - MA(1-12) and CA(1-8) - ME(1-12) have strong antibacterial activity but only CA(1-8) - ME(1-12) has hemolytic activity against human erythrocytes. CA(1-8) - MA(1-12) has a hydrophobic 310-helix of only two turns combined with one short helix in the N-terminus with a flexible hinge section in between. CA(1-8) - MA(1-12) has a severely bent structure in the middle of the peptide. These structural features as well as the low hydrophobicity of CA(1-8) - MA(1-12) seem to be crucial for the selective lysis against the membrane of prokaryotic cells. CA(1-8) - ME(1-12) has an alpha-helical structure of about three turns in the melittin domain and a flexible structure with one turn in the cecropin domain connected with a flexible hinge section in between, and these might be the structural features required for membrane disruption against prokaryotic and eukaryotic cells. The central hinge region (Gly9-Ile10-Gly11) in an amphipathic antibacterial peptide is considered to play an important role in providing the conformational flexibility required for ion channel formation of the C-terminal hydrophobic alpha-helix on cell membrane.

Topics: Amino Acid Sequence; Anti-Bacterial Agents; Antimicrobial Cationic Peptides; Carcinoma, Small Cell; Circular Dichroism; Erythrocytes; Hemolysin Proteins; Humans; Lung Neoplasms; Magnetic Resonance Spectroscopy; Melitten; Models, Molecular; Molecular Sequence Data; Peptides; Protein Conformation; Structure-Activity Relationship; Tumor Cells, Cultured