A Novel Application of Ti-Substituted Polyoxometalates: Anti-Inflammatory Activity in OVA-Induced Asthma Murine Model

Polyoxometalates Impact as Anticancer Agents

Polyoxometalates (POMs) are oxoanions of transition metal ions, such as V, Mo, W, Nb, and Pd, forming a variety of structures with a wide range of applications. Herein, we analyzed recent studies on the effects of polyoxometalates as anticancer agents, particularly their effects on the cell cycle. To this end, a literature search was carried out between March and June 2022, using the keywords "polyoxometalates" and "cell cycle". The effects of POMs on selected cell lines can be diverse, such as their effects in the cell cycle, protein expression, mitochondrial effects, reactive oxygen species (ROS) production, cell death and cell viability. The present study focused on cell viability and cell cycle arrest. Cell viability was analyzed by dividing the POMs into sections according to the constituent compound, namely polyoxovanadates (POVs), polyoxomolybdates (POMos), polyoxopaladates (POPds) and polyoxotungstates (POTs). When comparing and sorting the IC50 values in ascending order, we obtained first POVs, then POTs, POPds and, finally, POMos. When comparing clinically approved drugs and POMs, better results of POMs in relation to drugs were observed in many cases, since the dose required to have an inhibitory concentration of 50% is 2 to 200 times less, depending on the POMs, highlighting that these compounds could become in the future an alternative to existing drugs in cancer therapy.

Polyoxometalates in Biomedicine: Update and Overview

BACKGROUND

Polyoxometalates (POMs) are negatively charged metal-oxo clusters of early transition metal ions in high oxidation states (e.g., WVI, MoVI, VV). POMs are of interest in the fields of catalysis, electronics, magnetic materials and nanotechnology. Moreover, POMs were shown to exhibit biological activities in vitro and in vivo, such as antitumor, antimicrobial, and antidiabetic.

METHODS

The literature search for this peer-reviewed article was performed using PubMed and Scopus databases with the help of appropriate keywords.

RESULTS

This review gives a comprehensive overview of recent studies regarding biological activities of polyoxometalates, and their biomedical applications as promising anti-viral, anti-bacterial, anti-tumor, and anti-diabetic agents. Additionally, their putative mechanisms of action and molecular targets are particularly considered.

CONCLUSION

Although a wide range of biological activities of Polyoxometalates (POMs) has been reported, they are to the best of our knowledge not close to a clinical trial or a final application in the treatment of diabetes or infectious and malignant diseases. Accordingly, further studies should be directed towards determining the mechanism of POM biological actions, which would enable fine-tuning at the molecular level, and consequently efficient action towards biological targets and as low toxicity as possible. Furthermore, biomedical studies should be performed on solutionstable POMs employing physiological conditions and concentrations.

Vitamin A deficiency execrates Lewis lung carcinoma via induction of type 2 innate lymphoid cells and alternatively activates macrophages

BACKGROUND

Lung carcinoma is still associated with high rates of morbidity and mortality despite the advances in cancer therapy achieved in last decades. Recent studies showed that immune responses played a crucial role in the developments of cancers including lung cancer. Type 1 immune response could promote classical activated macrophages (CAMs) with antitumor properties. On the contrast, type 2 immune response could lead to the polarization of alternatively activated macrophages (AAMs) which could promote the growth and metastasis of tumor. Our previous research showed that vitamin A deficiency could promote the type 2 immune response but not the type 1 immune response. Whether vitamin A deficiency has detrimental effect for lung carcinoma need further investigate.

AIM

To investigate the effect of vitamin A deficiency in lung cancer and the potential mechanisms.

METHODS

Mice were fed with normal diet or vitamin A deficiency diet for 2 weeks, and then, Lewis lung cancer (LLC) cells dissolved in Matrigel Matrix were planted on the left lower lope of lungs. Mice were sacrificed 28 days after the plantation of tumor cells, the tumor size, cytokine profile in bronchoalveolar lavage fluid (BALF), numbers of type 2 innate lymphoid cells (ILC2s), and macrophage phenotypes in the lung were measured. The overall survival rate was also monitored throughout the experiments.

RESULTS

Vitamin A deficiency diet fed tumor-bearing mice have lower survival rate (χ 2 = 6.862, p < 0.001), larger tumor size (t = 2.651, p < 0.05), more ILC2s (t = 7.680, p < 0.001), and AAMs (t = 6.315, p < 0.001) in the lung tissue; also, type 2 cytokines concentrations in the BALF were higher compared to normal diet fed ones.

CONCLUSION

Vitamin A deficiency could promote the pathogeneses of lung carcinoma via induction of ILC2s and polarizing AAMs.

Deficiency in IL-33/ST2 Axis Reshapes Mitochondrial Metabolism in Lipopolysaccharide-Stimulated Macrophages

The polarization and function of macrophages play essential roles in controlling immune responses. Interleukin (IL)-33 is a member of the IL-1 family that has been shown to influence macrophage activation and polarization, but the underlying mechanisms are not fully understood. Mitochondrial metabolism has been reported to be a central player in shaping macrophage polarization; previous studies have shown that both aerobic glycolysis and oxidative phosphorylation uniquely regulate the functions of M1 and M2 macrophages. Whether IL-33 polarizes macrophages by reshaping mitochondrial metabolism requires further investigation. In this work, we examined the mitochondrial metabolism of bone marrow-derived macrophages (BMDMs) from either wild type (WT), Il33-overexpressing, or IL-33 receptor knockout (St2^−/−) mice challenged with lipopolysaccharide (LPS). We found that after LPS stimulation, compared with WT BMDMs, St2^−/− BMDMs had reduced cytokine production and increased numbers and activity of mitochondria via the metabolism regulator peroxisome proliferator-activated receptor-C coactivator-1 α (PGC1α). This was demonstrated by increased mitochondrial DNA copy number, mitochondria counts, mitochondria fission- and fusion-related gene expression, oxygen consumption rates, and ATP production, and decreased glucose uptake, lactate production, and extracellular acidification rates. For Il33-overexpressing BMDMs, the metabolic reprogramming upon LPS stimulation was similar to WT BMDMs, and was accompanied by increased M1 macrophage activity. Our findings suggested that the pleiotropic IL-33/ST2 pathway may influence the polarization and function of macrophages by regulating mitochondrial metabolism.