Antitumor effects of a Sb-rich polyoxometalate on non-small-cell lung cancer by inducing ferroptosis and apoptosis.

Polyoxometalates (POMs) are a class of anionic metal-oxygen clusters with versatile biological activities. Over the past decade, an increasing number of POMs, especially Sb-rich POMs, have been proven to exert antitumor activity. However, the antitumor effects and mechanisms of POMs in the treatment of non-small cell lung cancer (NSCLC) remain largely unexplored. This study employed a Sb-rich {Sb21Tb7W56} POM (POM-1) for NSCLC therapy and investigated its mechanism of action. Our results demonstrated that POM-1 exhibited cytotoxicity against H1299 and A549 cells with IC50 values of 3.245 µM and 3.591 µM, respectively. The migration and invasion were also inhibited by 28.05% and 76.18% in H1299 cells, as well as 36.88% and 36.98% in A549 cells at a concentration of 5 µM. In a tumor xenograft mouse model, POM-1 suppressed tumor growth by 76.92% and 84.62% at doses of 25 and 50 mg kg-1, respectively. Transcriptomic analysis indicated the alteration of ferroptosis and apoptosis signaling pathways in POM-treated NSCLC cells. Subsequent experimentation confirmed the induction of ferroptosis, evidenced by 5.6-fold elevated lipid peroxide levels with treatment of 5 µM POM-1, alongside increased expression of ferroptosis-associated proteins. Additionally, the apoptosis induced by POM-1 was also validated by the 19.67% and 30.1% increase in apoptotic cells in H1299 and A549 cells treated with 5 µM POM-1, respectively, as well as the upregulated activation of caspase-3. In summary, this study reveals, for the first time, ferroptosis as the antitumor mechanism of Sb-rich POM, and that synergism with ferroptosis and apoptosis is a highly potent antitumor strategy for POM-based antitumor therapy.

A Water-Soluble Antimony-Rich Polyoxometalate with Broad-Spectrum Antitumor Activities.

Herein, a giant Sb-rich polyoxometalate (POM) {Sb21 Tb7 W56 } is reported, which contains the largest number of Sb atoms in a POM so far. The Sb-rich POM has many interesting structural features and is a rare example of a soluble and water-stable giant POM. Biomedical studies indicate that the Sb-rich POM exhibits broad-spectrum antitumor activity against various cancer cell lines by reactivating the P53-dependent apoptotic processes and disrupting the mitochondrial membrane. In addition, this Sb-rich POM was capable of suppressing the growth and metastasis of a breast cancer in vivo. This work demonstrates that Sb-rich POMs are promising candidates for the development of new anticancer drugs.

A Molecular Combination of Zinc(II) Phthalocyanine and Tamoxifen Derivative for Dual Targeting Photodynamic Therapy and Hormone Therapy.

The combination of photodynamic therapy and other cancer treatment modalities is a promising strategy to enhance therapeutic efficacy and reduce side effects. In this study, a tamoxifen-zinc(II) phthalocyanine conjugate linked by a triethylene glycol chain has been synthesized and characterized. Having tamoxifen as the targeting moiety, the conjugate shows high specific affinity to MCF-7 breast cancer cells overexpressed estrogen receptors (ERs) and tumor tissues, therefore leading to a cytotoxic effect in the dark due to the cytostatic tamoxifen moiety, and a high photocytotoxicity due to the photosensitizing phthalocyanine unit against the MCF-7 cancer cells. The high photodynamic activity of the conjugate can be attributed to its high cellular uptake and efficiency in generating intracellular reactive oxygen species. Upon addition of exogenous 17ß-estradiol as an ER inhibitor, the cellular uptake and photocytotoxicity of the conjugate are reduced significantly. As shown by confocal microscopy, the conjugate is preferentially localized in the lysosomes of the MCF-7 cells.

Molecular-target-based anticancer photosensitizer: synthesis and in vitro photodynamic activity of erlotinib-zinc(II) phthalocyanine conjugates.

Targeted photodynamic therapy is a new promising therapeutic strategy to overcome growing problems in contemporary medicine, such as drug toxicity and drug resistance. A series of erlotinib-zinc(II) phthalocyanine conjugates were designed and synthesized. Compared with unsubstituted zinc(II) phthalocyanine, these conjugates can successfully target EGFR-overexpressing cancer cells owing to the presence of the small molecular-target-based anticancer agent erlotinib. All conjugates were found to be essentially non-cytotoxic in the absence of light (up to 50 µM), but upon illumination, they show significantly high photo-cytotoxicity toward HepG2 cells, with IC50 values as low as 9.61-91.77 nM under a rather low light dose (λ=670 nm, 1.5 J cm(-2) ). Structure-activity relationships for these conjugates were assessed by determining their photophysical/photochemical properties, cellular uptake, and in vitro photodynamic activities. The results show that these conjugates are highly promising antitumor agents for molecular-target-based photodynamic therapy.

tert-Butyl N-{4-[N-(4-hy-droxy-phen-yl)carbamo-yl]benz-yl}carbamate.

In the title compound, C(19)H(22)N(2)O(4), the dihedral angle between the aromatic rings is 67.33 (2)°. In the crystal, mol-ecules are linked through N-H⋯O and O-H⋯O hydrogen bonds, generating a two-dimensional network lying parallel to (100). As a result of the twist of the mol-ecular skeleton and the hindrance of the tert-butyl groups, no π-π inter-actions exist between the aromatic rings.

tert-Butyl N-[6-(N,N-dipropyl-carbamo-yl)-1,3-benzothia-zol-2-yl]carbamate.

The title compound C(19)H(27)N(3)O(3)S, crystallizes with two unique mol-ecules in the asymmetric unit. The benzene ring of each benzothia-zole unit carries a dipropyl-carbamoyl substituent in the 6-position and a tert-butyl carbamate unit on each thia-zole ring. In the crystal structure, inter-molecular N-H⋯N and weak C-H⋯O hydrogen bonds form centrosymmetric dimers. Additional C-H⋯O contacts construct a three-dimensional network. A very weak C-H⋯π contact is also present.

Ethyl 2-(tert-butoxy-carbonyl-amino)-1,3-benzothia-zole-6-carboxyl-ate.

In the crystal of the title compound, C(15)H(18)N(2)O(4)S, inversion dimers are formed by inter-molecular N-H⋯N hydrogen bonds and weak C-H⋯O contacts. These dimers stack up along [100] through inversion-related π-π inter-actions between thia-zole rings [centroid-centroid distance = 3.790 (2) Å] and the thia-zole and benzene rings [centroid-centroid distance = 3.845 (2) Å] and C-H⋯π contacts.