RNA-binding protein RBM28 can translocate from the nucleolus to the nucleoplasm to inhibit the transcriptional activity of p53.

RNA-binding protein RBM28 (RBM28), as a nucleolar component of spliceosomal small nuclear ribonucleoproteins, is involved in the nucleolar stress response. Whether and how RBM28 regulates tumor progression remains unclear. Here, we report that RBM28 is frequently overexpressed in various types of cancer and that its upregulation is associated with a poor prognosis. Functional and mechanistic assays revealed that RBM28 promotes the survival and growth of cancer cells by interacting with the DNA-binding domain of tumor suppressor p53 to inhibit p53 transcriptional activity. Upon treatment with chemotherapeutic drugs (e.g., adriamycin), RBM28 is translocated from the nucleolus to the nucleoplasm, which is likely mediated via phosphorylation of RBM28 at Ser122 by DNA checkpoint kinases 1 and 2 (Chk1/2), indicating that RBM28 may act as a nucleolar stress sensor in response to DNA damage stress. Our findings not only reveal RBM28 as a potential biomarker and therapeutic target for cancers but also provide mechanistic insights into how cancer cells convert stress signals into a cellular response linking the nucleolus to regulation of the tumor suppressor p53.

Efficient gene editing through an intronic selection marker in cells.

BACKGROUND: Gene editing technology has provided researchers with the ability to modify genome sequences in almost all eukaryotes. Gene-edited cell lines are being used with increasing frequency in both bench research and targeted therapy. However, despite the great importance and universality of gene editing, the efficiency of homology-directed DNA repair (HDR) is too low, and base editors (BEs) cannot accomplish desired indel editing tasks. RESULTS AND DISCUSSION: Our group has improved HDR gene editing technology to indicate DNA variation with an independent selection marker using an HDR strategy, which we named Gene Editing through an Intronic Selection marker (GEIS). GEIS uses a simple process to avoid nonhomologous end joining (NHEJ)-mediated false-positive effects and achieves a DsRed positive rate as high as 87.5% after two rounds of fluorescence-activated cell sorter (FACS) selection without disturbing endogenous gene splicing and expression. We re-examined the correlation of the conversion tract and efficiency, and our data suggest that GEIS has the potential to edit approximately 97% of gene editing targets in human and mouse cells. The results of further comprehensive analysis suggest that the strategy may be useful for introducing multiple DNA variations in cells.

Effect of GADD45G on the radioresistance of nasopharyngeal carcinoma cells.

The development of radioresistance by nasopharyngeal carcinoma (NPC) cells almost always results in tumor recurrence and metastasis, making clinical treatment of the disease difficult. In this study, the mechanism of radioresistance in NPC cells was investigated. First, a gene array and quantitative reverse-transcription-PCR assays were used to screen for genes exhibiting significantly altered expression in the DNA damage signaling pathway. Based on those results, GADD45G was further studied in the context of radioresistance. A GADD45G-knockout NPC cell line (CNE-2R-KO) was constructed using CRISPR-Cas9 technology and used for a comparison of differences in radioresistance with other radiosensitive and radioresistant NPC cells, as evaluated using colony formation assays. Cell cycle changes were observed using flow cytometry. Cell proliferation and migration were measured using 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide and wound healing assays, respectively. The sequencing results revealed the successful construction of the CNE-2R-KO cell line, the radiosensitivity of which was higher than that of its parent radioresistant cell line owing to the GADD45G knockout. This was likely related to the increase in the number of cells in the G1 phase and decrease in those in the S1 phase as well as the increased cell proliferation rate and decreased migratory ability. GADD45G is associated with radioresistance in NPC cells and likely has a role in the occurrence and metastasis of NPC.

Acetylation-dependent function of human single-stranded DNA binding protein 1.

Human single-stranded DNA binding protein 1 (hSSB1) plays a critical role in responding to DNA damage and maintaining genome stability. However, the regulation of hSSB1 remains poorly studied. Here, we determined that hSSB1 acetylation at K94 mediated by the acetyltransferase p300 and the deacetylases SIRT4 and HDAC10 impaired its ubiquitin-mediated degradation by proteasomes. Moreover, we demonstrated that the hSSB1-K94R mutant had reduced cell survival in response to DNA damage by radiation or chemotherapy drugs. Furthermore, the p300/CBP inhibitor C646 significantly enhanced the sensitivity of cancer cells to chemotherapy drugs, and a positive correlation between hSSB1 and p300 level was observed in clinical colorectal cancer samples. Acetylation, a novel regulatory modification of hSSB1, is crucial for its function under both physiological and pathological conditions. This finding supports the notion that the combination of chemotherapy drugs with acetylation inhibitors may benefit cancer patients.

Down-regulation of prostate stem cell antigen (PSCA) by Slug promotes metastasis in nasopharyngeal carcinoma.

Distant metastasis and local recurrence are still the major causes for failure of treatment in patients with nasopharyngeal carcinoma (NPC), making it urgent to further elicit the molecular mechanisms of NPC metastasis. Using a gene microarray including transcription factors and known markers for cancer stem cells, prostate stem cell antigen (PSCA) was found to be significantly down-regulated in metastatic NPC in lymph node, compared to its primary tumour, and in NPC cell lines with high metastatic ability compared to those with low metastatic ability. NPC patients with low PSCA expression had a consistently poor metastasis-free survival (p = 0.003). Knockdown and overexpression of PSCA respectively enhanced and impaired the migration and invasion in vitro and the lung metastasis in vivo of NPC cells. Mechanistically, the enhancement of NPC metastasis by knocking down PSCA probably involved epithelial-mesenchymal transition (EMT), by up-regulating N-cadherin and ZEB1/2 and by activating RhoA. The down-regulation of PSCA in NPC cells resulted directly from the binding of Slug to the PSCA promoter. PSCA may be a potential diagnostic marker and therapeutic target for patients with NPC.

Dynamic pathway linking Pakistan flooding to East Asian heatwaves.

In July to August 2022, Pakistan suffered historic flooding while record-breaking heatwaves swept southern China, causing severe socioeconomic impacts. Similar extreme events have frequently coincided between two regions during the past 44 years, but the underlying mechanisms remain unclear. Using observations and a suite of model experiments, here, we show that the upper-tropospheric divergent wind induced by convective heating over Pakistan excites a barotropic anomalous anticyclone over eastern China, which further leads to persistent heatwaves. Atmospheric model ensemble simulation indicates that this dynamic pathway linking Pakistan flooding and East Asian heatwaves is intrinsic to the climate system, largely independent of global sea surface temperature forcing. This dynamic connection is most active during July to August when convective variability is large over Pakistan and the associated divergent flow excites barotropic Rossby waves that propagate eastward along the upper troposphere westerly waveguide. This robust waveguide and the time delay offer hopes for improved subseasonal prediction of extreme events in East Asia.

A stratospheric precursor of East Asian summer droughts and floods.

East Asian floods and droughts in summer show a typical dipole pattern with a north-south oscillation centered near 30°N, called the southern drought-northern flood (SDNF) pattern, which has caused significant economic losses and casualties in the past three decades. However, effective explanations and predictions are still challenging, making suitable disaster prevention more difficult. Here, we find that a key predictor of this dipole pattern is the Quasi-Biennial Oscillation (QBO, tropical winds above 10 km). The QBO can modulate precipitation in East Asia, contributing the largest explained variation of this dipole pattern. A QBO-included statistical model can effectively predict summer floods and droughts at least three months in advance and explain at least 75.8% of precipitation variation. More than 30% of the SDNF pattern is attributed to the QBO in July-August 2020 and 2021. This result suggests a good prospect for using the tropical mid- to upper atmosphere in seasonal forecasts for summer.

Up-regulation of RAN by MYBL2 maintains osteosarcoma cancer stem-like cells population during heterogeneous tumor generation.

Intratumor heterogeneity is one of the major features of cancers, leading to aggressive disease and treatment failure. Cancer stem-like cells (CSCs) are believed to give rise to the heterogeneous cell types within tumors. Hence, understanding the regulatory mechanism underlying the recurrence process of heterogeneous tumor by CSCs could facilitate the development of CSC-targeted therapies. Here, utilizing single-cell transcriptomics, we present the molecular profile of osteosarcoma CSCs-derived heterogeneous tumors consisting of CSC clusters, osteoprogenitor and differentiated cell types, such as pre-osteoblasts, osteoblasts and chondroblasts. Furthermore, by constructing the comprehensive map of modulated genes during CSCs self-renewal and differentiation, we identify RAN exhibiting specific peak expression in osteosarcoma CSCs clusters which is transcriptionally up-regulated by MYBL2. Functionality, MYBL2-RAN pathway promotes the CSCs self-renewal by enhancing the nuclear accumulation of MYC protein, which in turn boosts the overexpression of RAN as a positive feedback. Importantly, blockage of MYBL2-RAN pathway sensitizes CSCs to cisplatin treatment and synergistically enhanced the cisplatin-induced cytotoxicity. Both MYBL2 and RAN are highly expressed in clinical osteosarcoma tissues which indicate poor prognosis. Collectively, our study provides advanced insights into the regeneration process of heterogeneous tumor originating from CSCs and highlights the MYBL2-RAN pathway as a promising target for CSC-based therapy in osteosarcoma.

Activating STING/TBK1 suppresses tumor growth via degrading HPV16/18 E7 oncoproteins in cervical cancer.

Cervical cancer is the most common gynecologic cancer, etiologically related to persistent infection of human papillomavirus (HPV). Both the host innate immunity system and the invading HPV have developed sophisticated and effective mechanisms to counteract each other. As a central innate immune sensing signaling adaptor, stimulator of interferon genes (STING) plays a pivotal role in antiviral and antitumor immunity, while viral oncoproteins E7, especially from HPV16/18, are responsible for cell proliferation in cervical cancer, and can inhibit the activity of STING as reported. In this report, we find that activation of STING-TBK1 (TANK-binding kinase 1) promotes the ubiquitin-proteasome degradation of E7 oncoproteins to suppress cervical cancer growth. Mechanistically, TBK1 is able to phosphorylate HPV16/18 E7 oncoproteins at Ser71/Ser78, promoting the ubiquitination and degradation of E7 oncoproteins by E3 ligase HUWE1. Functionally, activated STING inhibits cervical cancer cell proliferation via down-regulating E7 oncoproteins in a TBK1-dependent manner and potentially synergizes with radiation to achieve better effects for antitumor. Furthermore, either genetically or pharmacologically activation of STING-TBK1 suppresses cervical cancer growth in mice, which is independent on its innate immune defense. In conclusion, our findings represent a new layer of the host innate immune defense against oncovirus and provide that activating STING/TBK1 could be a promising strategy to treat patients with HPV-positive cervical cancer.

Targeting the KAT8/YEATS4 Axis Represses Tumor Growth and Increases Cisplatin Sensitivity in Bladder Cancer.

Bladder cancer (BC) is one of the most common tumors characterized by a high rate of relapse and a lack of targeted therapy. Here, YEATS domain-containing protein 4 (YEATS4) is an essential gene for BC cell viability using CRISPR-Cas9 library screening is reported, and that HUWE1 is an E3 ligase responsible for YEATS4 ubiquitination and proteasomal degradation by the Protein Stability Regulators Screening Assay. KAT8-mediated acetylation of YEATS4 impaired its interaction with HUWE1 and consequently prevented its ubiquitination and degradation. The protein levels of YEATS4 and KAT8 are positively correlated and high levels of these two proteins are associated with poor overall survival in BC patients. Importantly, suppression of YEATS4 acetylation with the KAT8 inhibitor MG149 decreased YEATS4 acetylation, reduced cell viability, and sensitized BC cells to cisplatin treatment. The findings reveal a critical role of the KAT8/YEATS4 axis in both tumor growth and cisplatin sensitivity in BC cells, potentially generating a novel therapeutic strategy for BC patients.

Activated STING-containing R-EVs from iPSC-derived MSCs promote antitumor immunity.

We recently revealed that activated STING is secreted into RAB22A-induced extracellular vesicles (R-EVs) and promotes antitumor immunity in cancer cells. Whether mesenchymal stem cell (MSC)-derived R-EVs containing activated STING can be used as a novel antitumor immunotherapy remains unclear, as MSC-derived EVs are promising cell-free therapeutics due to their superior biocompatibility and safety, as well as low immunogenicity. Here, we report that induced pluripotent stem cell (iPSC)-derived MSCs can generate R-EVs with a size and mechanism of formation that are similar to those of R-EVs produced from cancer cells. Furthermore, these MSC-derived R-EVs containing activated STING induced IFNß expression in recipient THP-1 monocytes and antitumor immunity in mice. Our findings reveal that the use of MSC-derived R-EVs containing activated STING is a promising cell-free strategy for antitumor immunity.

Chromobox homolog 4 is correlated with prognosis and tumor cell growth in hepatocellular carcinoma.

BACKGROUND: Chromobox homolog 4 (CBX4) is a member of the chromobox family of Polycomb group proteins involved in the chromatin remodeling and transcriptional regulation. However, its clinical relevance in hepatocellular carcinoma (HCC) has not yet been explored. METHODS: Immunohistochemistry was used to analyze cytoplasmic expression of CBX4 in 246 HCC specimens. The expression of CBX4 in HCC cell lines and LO2 was detected by Western blot test. Cell cycle and MTT assays were used to determine the changes of cell growth capacity. The expression of downstream genes related to proliferation was detected by Western blot test. RESULTS: The expression of CBX4 was up-regulated in multiple HCC cell lines and clinical samples. Although the CBX4 protein was detectable in both nucleus and cytoplasm in HCC tumor tissues, the high expression of CBX4 in cytoplasm was correlated with the α-fetoprotein level in serum (P = 0.036), tumor size (P = 0.029), pathologic differentiation (P = 0.033), and tumor, node, metastasis classification system stages (P = 0.032). Moreover, HCC patients who had a high level of CBX4 in cytoplasm had a shorter overall survival (P = 0.003) and recurrence-free survival (P = 0.012). Indeed, using HCC cell line, knockdown of CBX4 led to down-regulating proliferating cell nuclear antigen and cyclin E2 as well as up-regulating p16, followed by decreased cell proliferation and impaired cell cycle progression. CONCLUSIONS: The cytoplasmic CBX4 protein may be a useful prognostic biomarker and a potential therapeutic target for HCC.

CRISPR screen identifies GATAD1 as a synthetic lethal target with CDK4/6 inhibitors in estrogen receptor-positive breast cancer.

Estrogen receptor-positive (ER+) breast cancer represents approximately two-thirds of all breast cancers and has a sustained risk of late disease recurrence. Combining cyclin-dependent kinase 4/6 (CDK4/6) inhibitors with anti-estrogen therapies significantly improves ER+ advanced breast cancer clinical outcomes. Despite promising clinical outcomes, intrinsic or acquired resistance to CDK4/6 inhibitors has limited their success. We used CRISPR to screen MCF-7 cells to explore the targets whose inhibition is synthetic lethal with CDK4/6 inhibitors in ER+ breast cancer cells. We found that GATA zinc finger domain containing 1 (GATAD1) is a new synthetic lethal target with CDK4/6 inhibitors in ER+ breast cancer cells. Mechanistically, GATAD1 promotes cell proliferation by transcriptionally inhibiting p21 in ER+ breast cancer cells. GATAD1 depletion decreased the phosphorylation of CDK2/4 and RB transcriptional corepressor 1 (RB1), inducing cell cycle arrest. P21 overexpression abolished the enhanced proliferation induced by GATAD1 overexpression. Our results identify GATAD1 as a therapeutic target in ER+ breast cancer, which is beneficial to provide a novel treatment strategy.

An investigation on pickering nano-emulsions stabilized by dihydromyricetin/high-amylose corn starch composite particles: Preparation conditions and carrier properties.

With dihydromyricetin (DMY)/high-amylose corn starch (HCS) composite particles as the emulsifier, Pickering nano-emulsions were fabricated by combining high-speed shearing and high-pressure homogenization. The effect of particle properties and processing conditions on the formation and physicochemical properties of the Pickering nano-emulsions was then investigated systematically. The results showed that the DMY content of the composite particles, the oil phase volume fraction of the emulsion, and the homogenization conditions had obvious effects on the droplet size of the emulsion, where appropriate DMY content in the composite particles (5-20%) contributed to the formation of stable Pickering nano-emulsions. The oil phase of the obtained emulsions exhibited good stability during high-temperature storage, and their ß-carotene protecting performance against UV irradiation was superior to the emulsion stabilized by Tween 20. The in vitro simulated digestion analysis indicated that the nano-emulsions developed by the composite particles could enhance the bioaccessibility of ß-carotene and inhibit starch hydrolysis.

Population structure and genetic diversity of Tamarix chinensis as revealed with microsatellite markers in two estuarine flats.

Background: Tamarix chinensis Lour. is a 3-6-meter-tall small tree with high salt- and alkali- tolerance and aggressive invasiveness, mainly distributed in the eastern part of China in warm-temperate and subtropical climate zones, yet there is little information available regarding genetic diversity and population structure. Methods: A total of 204 individuals of nine T. chinensis populations were investigated for genetic diversity and population structure using a set of 12 highly polymorphic microsatellite markers. Results: The total number of alleles detected was 162, the average number of effective allele was 4.607, the average polymorphism information content (PIC) value of the 12 loci was 0.685, and the mean observed heterozygosity (Ho) and the mean expected heterozygosity (He) was 0.653 and 0.711, respectively. Analysis of molecular variance (AMOVA) showed a 5.32% genetic variation among T. chinensis populations. Despite a low population differentiation, Bayesian clustering analysis, discriminant analysis of principal components (DAPC) and the unweighted pair group method with arithmetic mean (UPGMA) clearly identified three genetic clusters correlated to the populations' geographic origin: the northern populations including those from Yellow River Delta, the Fangshan (FS) population from Beijing, the Changyi (CY) population from Bohai Bay, the Huanjiabu (HHJ) population from Hangzhou Bay, and the remaining two populations from Hangzhou Bay. There was a significant relationship between the genetic distance and geographical distance of the paired populations. Gene flow (Nm) was 4.254 estimated from FST. Conclusion: T. chinensis possessed high genetic diversity comparable to tree species, and although the population differentiation is shallow, our results classified the sampled populations according to sampling localities, suggesting the different origins of the study populations.

Targeting the Lysosomal Degradation of Rab22a-NeoF1 Fusion Protein for Osteosarcoma Lung Metastasis.

Rab22a-NeoF fusion protein has recently been reported as a promising target for osteosarcoma lung metastasis. However, how this fusion protein is regulated in cells remains unknown. Here, using multiple screenings, it is reported that Rab22a-NeoF1 fusion protein is degraded by an E3 ligase STUB1 via the autophagy receptor NDP52-mediated lysosome pathway, which is facilitated by PINK1 kinase. Mechanistically, STUB1 catalyzes the K63-linked ubiquitin chains on lysine112 of Rab22a-NeoF1, which is responsible for the binding of Rab22a-NeoF1 to NDP52, resulting in lysosomal degradation of Rab22a-NeoF1. PINK1 is able to phosphorylate Rab22a-NeoF1 at serine120, which promotes ubiquitination and degradation of Rab22a-NeoF1. Consistently, by upregulating PINK1, Sorafenib and Regorafenib can inhibit osteosarcoma lung metastasis induced by Rab22a-NeoF1. These findings reveal that the lysosomal degradation of Rab22a-NeoF1 fusion protein is targetable for osteosarcoma lung metastasis, proposing that Sorafenib and Regorafenib may benefit cancer patients who are positive for the RAB22A-NeoF1 fusion gene.

Disrupting the phase separation of KAT8-IRF1 diminishes PD-L1 expression and promotes antitumor immunity.

Immunotherapies targeting the PD-1/PD-L1 axis have become first-line treatments in multiple cancers. However, only a limited subset of individuals achieves durable benefits because of the elusive mechanisms regulating PD-1/PD-L1. Here, we report that in cells exposed to interferon-γ (IFNγ), KAT8 undergoes phase separation with induced IRF1 and forms biomolecular condensates to upregulate PD-L1. Multivalency from both the specific and promiscuous interactions between IRF1 and KAT8 is required for condensate formation. KAT8-IRF1 condensation promotes IRF1 K78 acetylation and binding to the CD247 (PD-L1) promoter and further enriches the transcription apparatus to promote transcription of PD-L1 mRNA. Based on the mechanism of KAT8-IRF1 condensate formation, we identified the 2142-R8 blocking peptide, which disrupts KAT8-IRF1 condensate formation and consequently inhibits PD-L1 expression and enhances antitumor immunity in vitro and in vivo. Our findings reveal a key role of KAT8-IRF1 condensates in PD-L1 regulation and provide a competitive peptide to enhance antitumor immune responses.

Augmenting L3MBTL2-induced condensates suppresses tumor growth in osteosarcoma.

Osteosarcoma is a highly aggressive cancer and lacks effective therapeutic targets. We found that L3MBTL2 acts as a tumor suppressor by transcriptionally repressing IFIT2 in osteosarcoma. L3MBTL2 recruits the components of Polycomb repressive complex 1.6 to form condensates via both Pho-binding pockets and polybasic regions within carboxyl-terminal intrinsically disordered regions; the L3MBTL2-induced condensates are required for its tumor suppression. Multi-monoubiquitination of L3MBTL2 by UBE2O results in its proteasomal degradation, and the UBE2O/L3MBTL2 axis was crucial for osteosarcoma growth. There is a reverse correlation between L3MBTL2 and UBE2O in osteosarcoma tissues, and higher UBE2O and lower L3MBTL2 are associated with poorer prognosis in osteosarcoma. Pharmacological blockage of UBE2O by arsenic trioxide can enhance L3MBTL2-induced condensates and consequently suppress osteosarcoma growth. Our findings unveil a crucial biological function of L3MBTL2-induced condensates in mediating tumor suppression, proposing the UBE2O-L3MBTL2 axis as a potential cancer therapeutic target in osteosarcoma.

The trend and spatial spread of multisectoral climate extremes in CMIP6 models.

Climate change could exacerbate extreme climate events. This study investigated the global and continental representations of fourteen multisectoral climate indices during the historical (1979-2014), near future (2025-2060) and far future (2065-2100) periods under two emission scenarios, in eleven Coupled Model Intercomparison Project (CMIP) General Circulation Models (GCM). We ranked the GCMs based on five metrics centred on their temporal and spatial performances. Most models followed the reference pattern during the historical period. MPI-ESM ranked best in replicating the daily precipitation intensity (DPI) in Africa, while CANESM5 GCM ranked first in heatwave index (HI), maximum consecutive dry days (MCCD). Across the different continents, MPI-LR GCM performed best in replicating the DPI, except in Africa. The model ranks could provide valuable information when selecting appropriate GCM ensembles when focusing on climate extremes. A global evaluation of the multi-index causal effects for the various indices shows that the dry spell total length (DSTL) was the most crucial index modulating the MCCD for all continents. Also, most indices exhibited a positive climate change signal from the historical to the future. Therefore, it is crucial to design appropriate strategies to strengthen resilience to extreme climatic events while mitigating greenhouse gas emissions.