Background Recent Clinical trials of administration of epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) in combination with standard first-line chemotherapy have failed to improve survival in patients with advanced NSCLC, However, the sequential treatment with EGFR-TKIs and chemotherapy is expected to improve survival of NSCLC. The aim of this study is to test the antiproliferative effect of pemetrexed combined with icotinib in different sequences on non-small cell lung cancer (NSCLC) cell lines to determine the optimal combination schedule, and subsequently elaborated the potential mechanisms. Methods Six human lung cancer cell lines with wild-type or mutant EGFR gene were exposed to pemetrexed and icotinib combined in different sequences. Cell proliferation was examined by cell counting kit-8 (CCK-8) and colony formation assay; cell cycle and apoptosis were evaluated by flow cytometry; cell migration and invasion were measured by wound healing and transwell invasion assays respectively; protein expression was by detected by Western blot. Results The growth inhibition effect of pemetrexed combined with icotinib on NSCLC cells were schedule-dependent in vitro and in vivo. Treatment with pemetrexed followed by icotinib (P-I) had significantly stronger anticancer ability than treatment with icotinib followed by pemetrexed (I-P) and concomitant treatment with pemetrexed and icotinib (P + I). Cell cycle analysis revealed that pemetrexed blocked cells in S phase, whereas icotinib arrested cells in G1 phase. We also found that icotinib markedly enhanced the pro-apoptotic activity of pemetrexed via cytochrome-C/Caspase/Bcl-2 signaling pathway. In addition, our results showed that pemetrexed alone increased the levels of p-EGFR, p-AKT and p-MAPK, which were inhibited by icotinib. Finally, we showed that the washout period of icotinib was no less than 96 h. Conclusions Sequential treatment of NSCLC cells with pemetrexed followed by icotinib had powerful antiproliferative effect, and it could become a novel effective combination therapy for NSCLC patients.

Hepatocellular carcinoma (HCC) is one of the most aggressive malignancies. Elucidating the underlying mechanisms of this disease could provide new therapeutic strategies for treating HCC. Here, we identified a novel role of DEAD-box helicase 24 (DDX24), a member of the DEAD-box protein family, in promoting HCC progression. DDX24 levels were significantly elevated in HCC tissues and were associated with poor prognosis of HCC. Overexpression of DDX24 promoted HCC migration and proliferation in vitro and in vivo, whereas suppression of DDX24 inhibited both functions. Mechanistically, DDX24 bound the mRNA618-624nt of laminin subunit beta 1 (LAMB1) and increased its stability in a manner dependent upon the interaction between nucleolin (NCL) and the C-terminal region of DDX24. Moreover, RFX8 was identified as a DDX24 promoter-binding protein that transcriptionally upregulated DDX24 expression. Collectively, these findings demonstrate that the RFX8/DDX24/LAMB1 axis promotes HCC progression, providing potential therapeutic targets for HCC.

Human telomerase reverse transcriptase (hTERT) is highly expressed in many tumors and is essential for tumorigenesis and metastasis in multiple cancers. However, the molecular mechanisms underlying its high expression level in hepatocellular carcinoma (HCC) remain unclear. In this study, we identified X-ray repair cross-complementing 5 (XRCC5), a novel hTERT promoter-binding protein in HCC cells, using biotin-streptavidin-agarose pull-down assay. We found that XRCC5 was highly expressed in HCC cells, in which it transcriptionally upregulated hTERT. Functionally, the transgenic expression of XRCC5 promoted HCC progression and 5-fluorouracil resistance, whereas short hairpin RNA knockdown of XRCC5 had converse effects in vitro and in vivo. Moreover, hTERT overexpression reversed XRCC5 knockdown-or 5-fluorouracil (5-Fu)-mediated HCC inhibition. Mechanistically, nuclear-factor-erythroid-2-related factor 2 (NRF2) interacted with XRCC5, which in turn upregulated hTERT. However, the upregulation was insignificant when NRF2 was reduced, suggesting that the XRCC5-mediated hTERT expression was NRF2 dependent. The HCC patients with high expression levels of XRCC5 and hTERT had shorter overall survival times compared with those with low XRCC5 and hTERT levels in their tumor tissues. Collectively, our study demonstrates the molecular mechanisms of the XRCC5/NRF2/hTERT signaling in HCC metastasis, which will aid in the identification of novel strategies for the diagnosis and treatment of HCC.

Purpose: Non-small cell lung cancer (NSCLC) is a leading cause of cancer death, and metastasis is a crucial determinant of increased cancer mortality. DDX24 has garnered increased attention due to its correlation with tumorigenesis and malignant progression. However, the correlation between DDX24 and NSCLC remains unclear.Methods: DDX24 expression in NSCLC tissues and survival rate of patients was analyzed using bioinformatic analysis. Transwell assays, wound-healing assays, and tail vein lung colonization models were employed to determine the role of DDX24 in migration and invasion in vitro and in vivo. We searched for DDX24interacting proteins using co-immunoprecipitation followed by mass spectroscopy and verified the interaction. The influence of DDX24 on RPL5 expression and ubiquitination was examined using protein stability assays.Results: DDX24 expression was upregulated in NSCLC cell lines and tumors of patients, particularly those with high tumor grades. A high DDX24 level was also correlated with a poor prognosis. DDX24 upregulation enhanced the migration and invasion ability of NSCLC cells, whereas its downregulation had the opposite effects. In vivo xenograft experiments confirmed that tumors with high DDX24

Immune checkpoint blockade (ICB) utilizing programmed death ligand-1 (PD-L1) antibody is a promising treatment strategy in solid tumors. However, in fact, more than half of hepatocellular carcinoma (HCC) patients are unresponsive to PD-L1-based ICB treatment due to multiple immune evasion mechanisms such as the hyperactivation of inflammation pathway, excessive tumor-associated macrophages (TAMs) infiltration, and insufficient infiltration of T cells. Herein, an inflammation-regulated nanodrug was designed to codeliver NF-κB inhibitor curcumin and PD-L1 antibody to reprogram the tumor microenvironment (TME) and activate antitumor immunity. The nanodrug accumulated in TME by an enhanced permeability and retention effect, where it left antibody to block PD-L1 on the membrane of tumor cells and TAMs due to pH-responsiveness. Simultaneously, a new curcumin-encapsulated nanodrug was generated, which was easily absorbed by either tumor cells or TAMs to inhibit the nuclear factor kappa-B (NF-κB) signal and related immunosuppressive genes. The inflammation-regulated nanodrug possessed good biocompatibility. Simultaneously, it reprogrammed TME effectively and exhibited an effective anticancer effect in immunocompetent mice. Overall, this study provided a potent strategy to improve the efficiency of ICB-based treatment for HCC.

Purpose To identify the spectrum of RB1 gene mutations in 114 Chinese patients with retinoblastoma. Methods Genomic DNA was extracted from the peripheral blood of 114 Rb patients. Polymerase chain reactions (PCRs) followed by direct Sanger sequencing were used to screen for mutations in the RB1 gene, which contains 26 exons with flanking intronic sequences, except exon 15. Clinical data, including gender, age at diagnosis, laterality of ocular lesions, and associated symptoms, were recorded and compared. Results We identified five novel mutations in the RB1 gene. Twenty-five other mutations found in this study have been previously reported. A higher rate of RB1 mutations, with 47.3% of mutations among bilaterally affected patients vs. 6.8% within unilaterally affected patients, was also observed (p < 0.0001). Bilaterally affected patients were diagnosed earlier when compared to unilaterally affected patients (11 ± 7 months versus 20 ± 14 months, p = 0.0002). Furthermore, nonsense mutations were abundant (n = 14), followed by frameshift mutations (n = 8), splicing site mutations (n = 5), while missense mutations were few (n = 3). Conclusions We found five novel mutations in RB1 genes, which expands the mutational spectrum of the gene. Children with bilateral Rb exhibited higher mutation rates and were diagnosed earlier than those with unilateral Rb. These findings will inform clinical diagnosis and genetic therapeutic targeting in Rb patients.

Sorafenib (SFN) is a multi-kinase inhibitor drug for the treatment of advanced hepatocellular carcinoma (HCC), but its limited efficacy is a major obstacle to the clinical outcomes of patients with HCC. We aimed to explore a novel molecular mechanism underlying the chemosensitivity of HCC to SFN, and to identify a promising therapeutic target for HCC treatment. In this study, bioinformatic analysis revealed that DDX24 was associated with poor survival in HCC cases, and significantly related to the pathways modulating tumor development. DDX24 regulated HCC cell proliferation and migration potentials. Moreover, reduction of DDX24 promoted the sorafenib-mediated inhibition of HCC cell growth and migration, the elevation of sorafenib-induced HCC cell apoptosis. DDX24 overexpression suppressed the inhibitory effect of SFN on cell proliferation and migration and reduced the apoptosis induced by SFN. Further, DDX24, combined with SFN treatment, presented a synergistic enhancement of the sensitivity of SFN to the growth and migration of HCC cells via AKT/ERK and the epithelial-mesenchymal transition (EMT) pathways, and that it modulated apoptosis via the caspase/PARP pathway. Mechanistically, SNORA18 served as a target gene for DDX24, regulating the chemosensitivity of sorafenib-treated HCC cells. Furthermore, SNORA18 knockdown or overexpression could partially reverse the inhibition or elevation of cell viability, colony formation and migration induced by DDX24 in sorafenib-treated HCC cells, respectively. Collectively, our results suggest that DDX24 regulates the chemosensitivity of HCC to SFN by mediating the expression of SNORA18, which may act as an effective therapeutic target for improving SFN efficiency in HCC treatment.

<div>Abstract<p>Hepatocellular carcinoma (HCC) is one of the most aggressive malignancies. Elucidating the underlying mechanisms of this disease could provide new therapeutic strategies for treating HCC. Here, we identified a novel role of DEAD-box helicase 24 (DDX24), a member of the DEAD-box protein family, in promoting HCC progression. DDX24 levels were significantly elevated in HCC tissues and were associated with poor prognosis of HCC. Overexpression of DDX24 promoted HCC migration and proliferation <i>in vitro</i> and <i>in vivo</i>, whereas suppression of DDX24 inhibited both functions. Mechanistically, DDX24 bound the mRNA618–624nt of laminin subunit beta 1 (LAMB1) and increased its stability in a manner dependent upon the interaction between nucleolin and the C-terminal region of DDX24. Moreover, regulatory factor X8 (RFX8) was identified as a DDX24 promoter-binding protein that transcriptionally upregulated DDX24 expression. Collectively, these findings demonstrate that the RFX8/DDX24/LAMB1 axis promotes HCC progression, providing potential therapeutic targets for HCC.</p>Significance:<p>The identification of a tumor-promoting role of DDX24 and the elucidation of the underlying regulatory mechanism provide potential prognostic indicators and therapeutic approaches to help improve the outcome of patients with hepatocellular carcinoma.</p></div>