Modulating DNA damage response in uveal melanoma through embryonic stem cell microenvironment.

BACKGROUND: Uveal melanoma (UVM) is the most common primary intraocular tumor in adults, with a median survival of 4-5 months following metastasis. DNA damage response (DDR) upregulation in UVM, which could be linked to its frequent activation of the PI3K/AKT pathway, contributes to its treatment resistance. We have reported that embryonic stem cell microenvironments (ESCMe) can revert cancer cells to less aggressive states through downregulation of the PI3K signaling, showing promise in modulating the DDR of UVM. METHODS: Since nonhomologous end joining (NHEJ) is the main DNA repair mechanism in UVM, this study utilized gene expression analysis and survival prognosis analysis to investigate the role of NHEJ-related genes in UVM based on public databases. Xenograft mouse models were established to assess the therapeutic potential of ESC transplantation and exposure to ESC-conditioned medium (ESC-CM) on key DNA repair pathways in UVM. Quantitative PCR and immunohistochemistry were used to analyze NHEJ pathway-related gene expression in UVM and surrounding normal tissues. Apoptosis in UVM tissues was evaluated using the TUNEL assay. RESULTS: PRKDC, KU70, XRCC5, LIG4 and PARP1 showed significant correlations with UM progression. High expression of PRKDC and XRCC5 predicted poorer overall survival, while low PARP1 and XRCC6 expression predicted better disease-free survival in UVM patients. ESCMe treatment significantly inhibited the NHEJ pathway transcriptionally and translationally and promoted apoptosis in tumor tissues in mice bearing UVM. Furthermore, ESC transplantation enhanced DDR activities in surrounding normal cells, potentially mitigating the side effects of cancer therapy. Notably, direct cell-to-cell contact with ESCs was more effective than their secreted factors in regulating the NHEJ pathway. CONCLUSIONS: Our results suggest that NHEJ-related genes might serve as prognostic markers and therapeutic targets in UVM. These findings support the therapeutic potential of ESC-based therapy in enhancing UVM sensitivity to radiochemotherapy and improving treatment outcomes while minimizing damage to healthy cells.

Multivariate MOFs for laser writing of alloy nanoparticle patterns.

We report three methods for the synthesis of alloy nanoparticles by a laser in air, where three types of MOF precursors are used. Multivariate MOFs, containing different metals in the single crystal backbone, provide continuous tuning of the metal content and excellent uniformity of metal dispersion.

Nanoscale Laser Metallurgy and Patterning in Air Using MOFs.

We report metallurgy on the nanoscale to generate metal nanoparticles and their simultaneous patterning in a single step. This is achieved by the self-reduction of porous metal-organic framework crystals using nanosecond pulsed laser irradiation. Metal nanoparticles of Fe, Co, Ni, Cu, Zn, Cd, In, Bi, and Pb with uniform sizes (controllable between 3 to 200 nm) and gaps (as narrow as 2 nm) are produced by nine different metal-organic frameworks, where atomically dispersed non-noble metal ions are reduced and gathered across the pores. The instant light absorption and cooling at local positions by a laser allows for precise and efficient patterning of metal nanoparticles. This new method is suitable for device fabrication at a speed of 15 mm2 s-1 on glass, consuming only 1.5 W of power. A large variety of metal nanoparticle three-dimensional architectures are demonstrated, among which one architecture exhibits an enhanced plasmonic effect homogeneously across the entire pattern for the detection of molecules at an extremely low concentration (10-12 M). These architectures are extremely stable under air and humidity during production, use, and storage, without altering the oxidation state, for 6 months.