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.

Intraocular Suture Technique for Flapless Two-Point Fixation of Four Fenestrated Haptics Intraocular Lenses.

PURPOSE: To describe a flapless technique for two-point fixation of intraocular lens (IOL) with four fenestrated haptics. METHODS: A transconjunctival puncture of 1-mL syringe needle was used to guide the suture needle out of the eye. The suture was taken out of the eye through the corneal incision, passed through the pair of fenestrated haptics of the IOL and then securely tied with overhand knots. The folded IOL was implanted into the posterior chamber. The anchor knots were created by both ends of the thread approximately 4 mm to 5 mm apart from the transconjunctival puncture and was intrasclerally buried. RESULTS: The technique was used in 18 eyes (18 patients). The mean postoperative follow-up period was 17.22 ± 8.82 months. The IOLs of all the eyes remained well positioned and stable at the final follow-up. The visual acuities of all the eyes were improved postoperatively. No suture loosening, suture erosion, hypotony, scleral atrophy, chronic inflammation, retinal tears, and/or detachments were observed in any of the patients. CONCLUSION: The present technique provides minimal trauma and reliable stability for the two-point transscleral fixation of four fenestrated haptics IOL.

Dynamic Measurement and Structural Decomposition of Deep Poverty in Contiguous Destitute Areas.

Based on the sample data from 2005 to 2019, this paper calculates the poverty nature of contiguous destitute areas through FGT index and its decomposition and systematically analyzes the impact of economic growth, inequality, and population change on poverty change. From the decomposition results of poverty change, we can see that, first, economic growth, inequality, and population change have different impacts on poverty change in counties and rural areas, and inequality and population mobility have widened the gap between them; second, population factor has always played a key role in the change of poverty, and the deceleration of population growth has a more significant impact on poverty change; third, the impact of the mobility on the poverty change of the counties is different from that of the rural areas. Accordingly, the paper puts forward some countermeasures and suggestions, such as promoting the organic connection between rural revitalization and poverty alleviation, speeding up rural governance, and promoting the process of urbanization.

Purification and structural characterization of human ERp29.

ERp29 is a major resident of the endoplasmic reticulum (ER) and is postulated to play an important molecular chaperone role in most animal cells. Human ERp29 was isolated to homogeneity in high yield by using a bacterial expression system. Its secondary structure was studied by circular dichroism (CD), Fourier transformed infrared spectroscopy (FTIR) and Raman spectroscopy and it was found that human ERp29 comprises significant alpha-helical structure. The details of its temperature-induced conformational changes was studied by CD and FTIR for the first time, revealing that the protein is stable below 50 degrees C and has two distinct structural transitions between 50 degrees C and 70 degrees C. This may shed light on ERp29's inability to protect substrate proteins against thermal aggregation.

Purification and structural study of the beta form of human cAMP-dependent protein kinase inhibitor.

The beta form of human cAMP-dependent protein kinase inhibitor (human PKIbeta), a novel heat-stable protein, was isolated with high yield using a bacterial expression system. Assays of PKI activity demonstrated that purified PKIbeta inhibits the catalytic subunit of cAMP-dependent protein kinase. FTIR, Raman spectroscopy and CD experiments implied that human PKIbeta contained only small amounts of alpha-helix and beta-structures, but large amounts of random coil and turn structures, which may explain its high thermostability. The details of its conformational changes in response to heat were studied by CD experiments for the first time, revealing that the protein unfolded at high temperature and refolded when decreased to room temperature.