Use of cucurbitacins for lung cancer research and therapy

An overview of the production and use of Bacillus thuringiensis toxin

The widespread utilization of traditional chemical pesticides has given rise to numerous negative impacts, leading to a surge in interest in exploring environmentally friendly alternatives. Bacillus thuringiensis (Bt), a bacterium renowned for its insecticidal properties, produces Cry proteins during its lifecycle. These proteins have distinct advantages over traditional chemical pesticides, including higher environmental safety, broader insecticidal spectra, and lower pesticide residues. Consequently, the discovery and application of Bt hold immense significance in plant disease and pest management, as well as in plant protection. Currently, Bt preparations occupy a prominent position as the world's largest and most widely used biopesticides. This article comprehensively reviews the fundamental aspects, insecticidal mechanisms, practical applications, and fermentation technologies related to Bt.

Cucurbitacins mitigate vascular neointimal hyperplasia by suppressing cyclin A2 expression and inhibiting VSMC proliferation

BACKGROUND

Restenosis frequently occurs after percutaneous angioplasty in patients with vascular occlusion and seriously threatens their health. Substantial evidence has revealed that preventing vascular smooth muscle cell proliferation using a drug-eluting stent is an effective approach to improve restenosis. Cucurbitacins have been demonstrated to exert an anti-proliferation effect in various tumors and a hypotensive effect. This study aims to investigate the role of cucurbitacins extracted from Cucumis melo L. (CuECs) and cucurbitacin B (CuB) on restenosis.

METHODS

C57BL/6 mice were subjected to left carotid artery ligation and subcutaneously injected with CuECs or CuB for 4 weeks. Hematoxylin-Eosin, immunofluorescence and immunohistochemistry staining were used to evaluate the effect of CuECs and CuB on neointimal hyperplasia. Western blot, real-time PCR, flow cytometry analysis, EdU staining and cellular immunofluorescence assay were employed to measure the effects of CuECs and CuB on cell proliferation and the cell cycle in vitro. The potential interactions of CuECs with cyclin A2 were performed by molecular docking.

RESULTS

The results demonstrated that both CuECs and CuB exhibited significant inhibitory effects on neointimal hyperplasia and proliferation of vascular smooth muscle cells. Furthermore, CuECs and CuB mediated cell cycle arrest at the S phase. Autodocking analysis demonstrated that CuB, CuD, CuE and CuI had high binding energy for cyclin A2. Our study also showed that CuECs and CuB dramatically inhibited FBS-induced cyclin A2 expression. Moreover, the expression of cyclin A2 in CuEC- and CuB-treated neointima was downregulated.

CONCLUSIONS

CuECs, especially CuB, exert an anti-proliferation effect in VSMCs and may be potential drugs to prevent restenosis.

Potential of cucurbitacin as an anticancer drug

In Chinese medicine, the Cucurbitaceae family contains many compounds known as cucurbitacins, which have been categorized into 12 classes ranging from A to T and more than 200 derivatives. Cucurbitacins are a class of highly oxidized tetracyclic triterpenoids with potent anticancer properties. The eight components of cucurbitacins with the strongest anticancer activity are cucurbitacins B, D, E, I, IIa, L-glucoside, Q, and R. Cucurbitacins have also been reported to suppress JAK-STAT 3, mTOR, VEGFR, Wnt/β-catenin, and MAPK signaling pathways, all of which are crucial for the survival and demise of cancer cells. In this paper, we review the progress in research on cucurbitacin-induced apoptosis, autophagy, cytoskeleton disruption, cell cycle arrest, inhibition of cell proliferation, inhibition of invasion and migration, inhibition of angiogenesis, epigenetic alterations, and synergistic anticancer effects in tumor cells. Recent studies have identified cucurbitacins as promising molecules for therapeutic innovation with broad versatility in immune response. Thus, cucurbitacin is a promising class of anticancer agents that can be used alone or in combination with chemotherapy and radiotherapy for the treatment of many types of cancer.Therefore, based on the research reports in the past five years at home and abroad, we further summarize and review the structural characteristics, chemical and biological activities, and studies of cucurbitacins based on the previous studies to provide a reference for further development and utilization of cucurbitacins.

A scientometrics and visualization analysis of oxidative stress modulator Nrf2 in cancer profiles its characteristics and reveals its association with immune response

Background

Nrf2, an essential and fascinating transcription factor, enjoys a dual property in the occurrence and development of inflammation and cancer. For over two decades, numerous studies regarding Nrf2 in cancer have been reported, whereas there is still a lack of a scientometrics and visualization analysis of Nrf2 in cancer. Hence, a scientometric study regarding the oxidative stress modulator Nrf2 was implemented.

Methods

After the quality screening, we defined 7168 relevant studies from 2000 to 2021. CiteSpace, VOSviewer, R software, and GraphPad Prism were used for the following scientometric study and visualization analysis, including field profiles, research hotspots, and future predictions.

Results

The total number of publications and citations are 1058 and 54,690, respectively. After polynomial fitting curve analysis, two prediction functions of the annual publication number (y = 3.3909x² - 13585x + 1 E+07) and citation number (185.45x² - 743669x + 7 E+08) were generated. After scientometric analysis, we found that Biochemistry Molecular Biology correlates with Nrf2 in cancer highly, and Free Radical Biology and Medicine is a good choice for submitting Nrf2-related manuscripts. The current research hotspots of Nrf2 in cancer mainly focus on cancer therapy and its cellular and molecular mechanisms. "antioxidant response element (87.5)", "gene expression (43.98)", "antioxidant responsive element (21.14)", "chemoprevention (20.05)", "carcinogenesis (19.2)", "cancer chemoprevention (18.45)", "free radical (17.15)", "response element (14.17)", and "chemopreventive agent (14.04)" are important for cancer therapy study. In addition, "glutathione-S-transferase (47)", "keap1 (15.39)", and "heme oxygenase 1 gene (24.35)" are important for inflammation and cell fate study. More interestingly, by performing an "InfoMap" algorithm, the thematic map showed that the "immune response" is essential to oxidative stress modulator Nrf2 but not well developed, indicating it deserves further exploration.

Conclusion

This study revealed field profiles, research hotspots, and future directions of oxidative stress modulator Nrf2 in inflammation and cancer research, and our findings will offer a vigorous roadmap for further studies in this field.

Cucurbitacin IIb Extracted from Hemsleya penxianensis Induces Cell Cycle Arrest and Apoptosis in Bladder Cancer Cells by Regulating Cell Cycle Checkpoints and Mitochondrial Apoptotic Pathway

Cucurbitacin IIb (CuIIb) extracted from Hemsleya penxianensis has been demonstrated anticancer activity in many malignancies, however, its effect against bladder cancer cells and the molecular mechanism remains unclear. Accordingly, in the present study, we evaluated the effect and further the underlying mechanism of CuIIb on bladder cancer cells. Cell viability and clonogenicity were examined to evaluate growth suppressive effect of CuIIb, alongside mechanism exploration was conducted based on RNA sequencing (RNA-seq). The results showed that CuIIb exposure inhibited the growth of T24 and UM-UC-3 bladder cancer cells as indicated by its obvious suppression on cell viability and clonogenicity. Mechanistic studies by RNA-seq and quantifying analysis of RNA-seq data by TMNP indicated cell cycle modulated by cell cycle checkpoints and apoptosis mediated by PI3K/Akt pathway might account for the anticancer activity of CuIIb. Consistently, results of flow cytometry and AO/EB staining demonstrated that the growth-suppressive effect of CuIIb was mediated by cell cycle arrest in G2/M phase and robust induction of cell apoptosis, which was further confirmed by immunoblotting and mitochondrial membrane potential (ΔΨm) analysis. Collectively, the results presented herein indicated that CuIIb exhibited anticancer activity on bladder cancer which may be a potential candidate for improving bladder cancer outcomes.

Heterodimers with a cucurbitane-type triterpenoid skeleton from the branches of Elaeocarpus dubius

Four undescribed and two known cucurbitane-type triterpenoids, including two heterodimers, elaeocarpudubins A and B, were isolated from the branches of Elaeocarpus dubius (Elaeocarpaceae). The chemical structures of these undescribed isolates were determined by analyses of 1D and 2D NMR and MS data, electronic circular dichroism (ECD) calculations, and chemical transformation. Biogenetically, elaeocarpudubins A and B might be derived from cucurbitacin F through Michael addition with vitamin C and (-)-catechin, respectively. These six isolates were evaluated for their cytotoxic activities against human leukemia HL-60, human lung adenocarcinoma A549, human hepatoma SMMC-7721, human breast cancer MCF-7, human colon cancer SW480, and paclitaxel-resistant A549 (A549/Taxol) cell lines, for their antioxidant properties using the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging assay, and for their differentiation effects on nerve growth factor (NGF)-mediated neurite outgrowth in rat pheochromocytoma PC12 cells. Cucurbitacins F (IC₅₀ of 4.98-38.11 μM) and D (IC₅₀ of 0.03-4.40 μM) showed growth-inhibitory activities against these six cancer cell lines. Elaeocarpudubin B (IC₅₀ of 61.04 μM) and elaeocarpudoside B (IC₅₀ of 6.93 μM) showed antioxidant activities. Elaeocarpudubin B and elaeocarpudoside B also showed neurite outgrowth-promoting activities in PC12 cells at a concentration of 10 μM.

Cucurbitacins as Potent Chemo-Preventive Agents: Mechanistic Insight and Recent Trends

Cucurbitacins constitute a group of cucumber-derived dietary lipids, highly oxidized tetracyclic triterpenoids, with potential medical uses. These compounds are known to interact with a variety of recognized cellular targets to impede the growth of cancer cells. Accumulating evidence has suggested that inhibition of tumor cell growth via induction of apoptosis, cell-cycle arrest, anti-metastasis and anti-angiogenesis are major promising chemo-preventive actions of cucurbitacins. Cucurbitacins may be a potential choice for investigations of synergism with other drugs to reverse cancer cells' treatment resistance. The detailed molecular mechanisms underlying these effects include interactions between cucurbitacins and numerous cellular targets (Bcl-2/Bax, caspases, STAT3, cyclins, NF-κB, COX-2, MMP-9, VEGF/R, etc.) as well as control of a variety of intracellular signal transduction pathways. The current study is focused on the efforts undertaken to find possible molecular targets for cucurbitacins in suppressing diverse malignant processes. The review is distinctive since it presents all potential molecular targets of cucurbitacins in cancer on one common podium.

Apoptotic Cell Death via Activation of DNA Degradation, Caspase-3 Activity, and Suppression of Bcl-2 Activity: An Evidence-Based Citrullus colocynthis Cytotoxicity Mechanism toward MCF-7 and A549 Cancer Cell Lines

The objectives of this study are to investigate the cytotoxic effect of different Citrullus colocynthis extracts on breast and lung cancer cell lines using flow cytometry to gain mechanistic insights. C. colocynthis was extracted sequentially using the Soxhlet method. We first tested the plant extracts’ cytotoxicity on non-malignant L929 cells and cancerous breast (MCF-7) and lung (A549) cell lines. We observed that the IC50 of the methanol extract on the viability of MCF-7 and A549 cell lines was 81.08 µg/mL and 17.84 µg/mL, respectively, using the MTT assay. The aqueous and methanol extracts were less toxic when tested against the non-cancerous L929 cell line, with IC50 values of 235.48 µg/mL and 222.29 µg/mL, respectively. Then, using flow cytometry, we investigated the underlying molecular pathways with Annexin-V, Anti-Bcl-2, Caspase-3, and DNA fragmentation (TUNEL) assays. Flow cytometric and molecular marker analyses revealed that the methanol extract activated caspase-3 and inhibited Bcl-2 protein, causing early and late apoptosis, as well as cell death via DNA damage in breast and lung cancer cells. These findings indicate that the methanol extract of C. colocynthis is cytotoxic to breast and lung cancer cell lines. The total phenolic and flavonoid content analysis results showed the methanolic extract of C. colocynthis has a concentration of 326.25 μg GAE/g dwt and 274.61 μg QE/g dwt, respectively. GC-MS analysis of the methanol extract revealed phytochemicals relevant to its cytotoxicity.