Reactive oxygen species are frequently associated with various cancers including pancreatic ductal adenocarcinomas (PDACs). Superoxide dismutase 2 (SOD2) is an enzyme that plays an important role in reactive oxygen species (ROS) signaling. Investigating the molecular function and biological functions of SOD2 can help us develop new therapeutic options and uncover new biomarkers for PDAC diagnosis and prognosis. Here, we show that nimbolide (NB), a triterpene limonoid, effectively blocks the growth and metastasis of PDACs by suppressing the expression and activity of SOD2. To identify the role of SOD2 in NB-induced anticancer activity, we used RNA interference to silence and plasmid transfection to overexpress it. Silencing SOD2 significantly reduced the growth and metastatic characteristics like epithelial-to-mesenchymal transition, invasion, migration, and colony-forming capabilities of PDACs, and NB treatment further reduced these characteristics. Conversely, the overexpression of SOD2 enhanced these metastatic characteristics. ROS signaling has a strong feedback mechanism with the PI3K/Akt signaling pathway, which could be mediated through SOD2. Finally, NB treatment to SOD2-overexpressing PDAC xenografts resulted in significant inhibition of tumor growth and metastasis. Overall, this work suggests that NB, a natural and safe phytochemical that silences SOD2 to induce high levels of ROS generation, results in increased apoptosis and reduced growth and progression of PDACs. The role of SOD2 in regulating NB-induced ROS generation presents itself as a therapeutic option for PDACs.

Glioblastoma (GBM) is the predominant primary malignant brain tumor. Metformin, a well-known antidiabetic medication, has emerged as a potential therapeutic candidate in the treatment of GBM. We have herein investigated two aspects of the effect of MTF on GBM cells: the effect of MTF on GBM cell viability, as previous studies have shown that MTF can selectively affect human GBM tumors; and the immunomodulatory effect of MTF on GBM, as there is evidence that inflammation is associated with GBM growth and progression. The human GBM cell line (U87) was exposed to various doses of MTF (1 mM, 20 mM, and 50 mM), followed by examination of cell viability and inflammatory mediator secretion at various time points. We observed that MTF treatment exerted a dose-response effect on glioblastoma multiforme cell viability. It also had an immunomodulatory effect on GBM cells. Our study identified several mechanisms that led to the overall inhibitory effect of MTF on human GBM. Further inquiry is necessary to gain a better understanding of how these in vitro findings would translate into successful in vivo approaches.

The two polar clinical forms of leprosy, termed tuberculoid and lepromatous, have polarized cellular immune responses with complex immunological distinctions. The predominance of DCs in tuberculoid leprosy has been reported, while the lepromatous pattern of illness is associated with weak activation of local populations of DCs. TiO₂ nanoparticles have previously been shown to induce maturation of these cells, leading to an inflammatory response similar to adjuvant usage in vaccine administration. We aimed to evaluate the effect of potassium-incorporated Ti oxide nanostructures, namely KTiO_xs, in the response of human monocyte-derived DCs to live M. leprae. Human monocytic cell line dual THP-1, which harbors two inducible reporter plasmid systems for transcription factor activation of NF-κB and interferon regulating factor (IRF), was treated with titanium control or with 1 mol/L KOH-treated Ti or 10 mol/L KOH for 24 h. Subsequently, cells were infected with M. leprae. KTiO_x nanoparticles increase DC phagocytic activity without inflammation. KTiO_x exposure of DCs led to an increase in IRF activation with modulation of the inflammatory response to live M. leprae. It also led to differential secretion of the critical components of innate immune response and the development of cell-mediated immunity against intracellular pathogens. This study demonstrates the effect of nanostructures of KTiO_xs and the usefulness of nanoparticle technology in the in vitro activation of human DCs against an infectious disease with a puzzling immune spectrum. Our findings may prompt future therapeutic strategies, such as DC immunotherapy for disseminated and progressive lepromatous lesions.

Background: IL-26 has demonstrated antimicrobial properties, as well as in the degradation of DNA from the Lyme disease spirochete Borrelia burgdorferi (Bb). Additionally, IL-26 can promote macrophage activation and enhance Bb phagocytotic activity. It is unclear if cell-mediated immune responses are modulated through TLR9 signaling when exposed to IL-26 Bb DNA complexes in post-treatment Lyme disease syndrome (PTLDS). Objective: We here aim to explore the effect of IL-26 in human Toll-like receptor (TLR)-9’s activation upon the recognition of Bb DNA. Methods: We utilized a single-receptor cell system, HEK-Dual™ hTLR9 cells, which harbors two reporter plasmids for the NF-κB and IL-8 signaling pathways. Bb DNA was exposed to increasing concentrations of IL-26 in monomeric or dimeric form and then used to stimulate the cells for 4 h. The TLR-9 ligand CpG was used as a control. Results: We observed that NF-κB and IL-8 activation was maximal when the cells were stimulated with Bb DNA that had been treated with 5 µM of IL-26 monomer and 1 µM of IL-26 dimer. The same was observed for IL-8 activation upon CpG stimulation. We observed, however, a decrease in NF-κB activation when treated with either form of IL-26. An NF-κB activation increase did not occur with IL-26-treated TLR9 ligand CpG. Conclusions: Our study shows an enhancement in NF-κB and IL-8 activation upon the recognition of IL-26-treated Bb DNA by TLR9, which suggests an increase in sensing by the TLR9 of Bb DNA when it is in the form of an IL-26-Bb DNA complex. These findings will prompt further studies on the interaction between IL-26 and Bb DNA.

Background/Objectives: Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive cancer with a high rate of recurrence and a dismal prognosis. Studies have shown that pancreatic cancer stem cells (PCSCs) are a subpopulation that contributes to tumor progression, resistance to therapeutics, and metastasis, making them a key subpopulation to target for treatment. Gedunin (GD), a natural compound derived from Azadirachta indica (neem), has shown anticancer properties in pancreatic cancer cells, but its effects on PCSCs remains unclear. This study evaluated the effects of GD in pancreatic cancer stem cells, highlighting its impacts on tumor growth and progression and focusing on its impact on the sonic hedgehog (Shh) signaling pathway. Methods: Functional assays were performed to assess the effect of GD on the sphere-forming ability, colony formation, and self-renewal of PCSCs. Athymic mice xenograft models were utilized to evaluate the tumor suppression effect of GD in vivo. Furthermore, the anticancer effect of GD on PCSCs was assessed using both in vitro and in vivo limiting dilution assay. GD-induced changes in Shh signaling and key stem cell marker expressions in PCSCs were evaluated. Results: GD effectively inhibited tumor growth in xenograft models and reduced the percentage of PCSCs. GD was effective in decreasing PCSCs’ proliferative, self-renewal, and colony-forming capacity. GD decreased the protein expression levels of key Shh signaling markers Gli1 and Shh, stem cell markers SOX2, Nanog, and Oct4, metastasis-related proteins MMP-2, MMP-3, and MMP-9, and EMT markers Tgf1, Slug, Snail, and Twist in both PDAC cells and PCSCs. We demonstrated a significant decrease in the spheroid formation and self-renewal capacity of the (ALDH+) PCSC population following GD treatment in HPAC cells, indicating its potential antagonistic effects on PCSCs. GD was highly effective in reducing tumor volume, stemness, and metastasis in both early and late chemotherapy. In vivo limiting dilution assay using CD133+/LGR5+ PCSC xenografts demonstrated that GD reduces tumor growth, metastasis, and stemness associated with PCSCs by downregulating the expression of Shh and Gli1. GD treatment also reduced micrometastatic lesions in the lung, liver, and brain, as identified using H&E staining. Conclusions: The findings highlight GD’s potential as a promising therapeutic candidate for PDAC, with the ability to target both bulk tumor cells and PCSCs. By simultaneously suppressing tumor growth, stemness, and metastatic spread, GD may contribute to more effective treatment strategies and improved patient outcomes.