The lactylation index predicts the immune microenvironment and prognosis of pan-cancer patients

Background:Protein lactylation is a new way for the“metabolic waste”lactic acid to perform novel functions.Nevertheless,our understanding of the contribution of protein lactylation to both tumor progression and therapeutic interventions remains imited.The construction of a scoring system for lactylation to predict the prognosis of pancancer patients and to evaluate the tumor immune microenvironment(TIME)would improve our understanding of the clinical significance of lactylation.Methods:Consensus clustering analysis of lactylation-related genes was used to cluster 177 pancreatic adenocarcinoma(PAAD)patients.Subsequently,a scoring system was developed using the least absolute shrinkage and selection operator(LASSO)regression.Internal validation and external validation were both conducted to assess and confirm the predictive accuracy of the scoring system.Finally,leucine rich repeat containing 1(LRRC1),a newly discovered lactylation-related gene,was analyzed in PAAD in vitro.Results:Utilizing the profiles of 332 lactylation-related genes,a total of 177 patients with PAAD were segregated into two distinct groups.LacCluster^(high) patients had a poorer prognosis than LacCluster^(low) patients.Through the differential analysis between the LacCluster^(high) and LacCluster^(low) groups,we identified additional genes associated with lactylation.These genes were then integrated to construct the LacCluster-enhanced system,which enabled more accurate prognosis prediction for patients with PAAD.Then,a lactylation index containing three genes(LacI-3)was constructed using LASSO regression.This was done to enhance the usability of the LacCluster-enhanced system in the clinic.Compared to those in the LacI-3^(high) subgroup,patients in the LacI-3^(low) subgroup exhibited increased expression of immune checkpoint-related genes,more immune cell infiltration,lower tumor mutation burdens,and better prognoses,indicating a“hot tumor”phenotype.Moreover,knocking down the expression of LRRC1,the hub gene in the LacI-3 scoring system,inhibited PAAD cell invasion,migration,and proliferation in vitro.Ultimately,the significance of LacI-3 across cancers was confirmed.Conclusion:Our findings strongly imply that protein lactylation may represent a new approach to diagnosing and treating malignant tumors.

Near infrared light triggered nitric oxide releasing platform based on upconversion nanoparticles for synergistic therapy of cancer stem-like cells

Near infrared(NIR) light-driven nitric oxide(NO) release nano-platform based on upconversion nanoparticles(UCNPs) and light sensitive NO precursor Roussin's black salt(RBS) was fabricated to generate NO upon 808 nm irradiation. The application of 808 nm laser as the excitation source could achieve better penetration depth and avoid overheating problem. The combination of UCNPs and RBS could realize the on-demand release of NO at desired time and location by simply controlling the output of NIR laser.Cellular uptake results showed that more nanoparticles were internalized in cancer stem-like cells(CSCs)rather than non-CSCs. Therefore, a synergistic cancer therapy strategy to eradicate both CSCs and nonCSCs simultaneously was developed. Traditional chemo-drug could inhibit non-CSCs but has low killing efficiency in CSCs. However, we found that the combination of NO and chemotherapy could efficiently inhibit CSCs in bulk cells, including inhibiting mammosphere formation ability, decreasing CD44^+/CD24^- subpopulation and reducing tumorigenic ability. The mechanism studies confirmed that NO could not only induce apoptosis but also increase drug sensitivity by declining drug efflux in CSCs. This UCNPsbased platform may provide a new combinatorial strategy of NO and chemotherapy to improve cancer treatment.