Biology subjects

Hu, C.

Publications and source records attributed to Hu, C..

At least 91 records · Page 5Linked to original sources

bioRxiv2023

NDC80 status pinpoints mitotic kinase inhibitors as emerging therapeutic options in clear cell renal cell carcinoma

[~]30% of clear cell renal cell carcinoma (ccRCC) patients present with metastatic disease at the time of diagnosis, causing a dire 5-year survival rate of 13%. Whereas anti-PD-1 immunotherapy has improved survival, a strong need remains for new therapeutic options. Using integrated network analysis, we identified the mitotic regulator NDC80 as a predictor of ccRCC progression. Overexpression of NDC80 fosters the malignant phenotype by promoting cell cycle progression through S phase as well as boosting glycolysis and mitochondrial respiration. Despite high levels of immune infiltration, particularly derived from tumor resident CD8+ T cells with an exhausted phenotype, NDC80 defines a class of ccRCCs that poorly respond to immune checkpoint blockade. Instead, bioinformatics identified NDC80-high ccRCCs as sensitive to inhibitors of mitotic kinases, PLK1 and AURK, therapeutic approaches we validated in cell lines and mouse xenograft studies. Thus, NDC80 status pinpoints mitotic kinase inhibitors as promising therapeutic options in difficult-to-treat ccRCCs.

cancer biology↗

bioRxiv2023

Transcription factor AhR regulates glutathione S-transferases (GSTs) conferring resistance to lambda-cyhalothrin in Cydia pomonella

Transcription factor aryl hydrocarbon receptor (AhR) can enhance insect resistance to insecticides by regulating the detoxification metabolic network. Our previous studies have confirmed that overexpression of cytochrome P450 monooxygenases (P450s) and glutathione S-transferases (GSTs) are both involved in lambda-cyhalothrin resistance in Cydia pomonella. In this study, we report that AhR regulates GSTs thus conferring lambda-cyhalothrin resistance in C. pomonella. Spatiotemporal expression patterns indicated that AhR gene of C. pomonella (CpAhR) was highly expressed in the Malpighian tubules of larvae. Moreover, the expression of CpAhR was induced by lambda-cyhalothrin exposure and was up-regulated in a lambda-cyhalothrin-resistant population. RNA interference (RNAi) of the expression of CpAhR could effectively decrease the relative expression level of CpGSTe3 and enzyme activity of GSTs, but not P450s, further reducing the tolerance of larvae to lambda-cyhalothrin. Furthermore, {beta}-naphthoflavone (BNF), a novel agonist of AhR, can effectively increase the expression of CpAhR and the activity of the GSTs enzyme, resulting in the enhancement of larvae tolerance to lambda-cyhalothrin. These results demonstrate that lambda-cyhalothrin exposure can effectively activate the expression of CpAhR and increase GSTs enzyme thus leading to the development of resistance to lambda-cyhalothrin, which enriches the theory of insecticide resistance regulation in C. pomonella.

molecular biology↗

bioRxiv2022

Alternative Polyadenylation alters UBASH3B-ZNF652 competition to involve in Triple-Negative Breast Cancer

Alternative polyadenylation (APA) is an RNA-processing mechanism which may affect gene expression. Its involvements in cancers including the triple-negative breast cancer (TNBC) have been demonstrated in previous studies. Given the lack of biomarkers for TNBC, in this study, we were committed to finding novel biomarkers related to TNBC prognosis from the perspective of APA-mediated microRNA regulation. For this goal, raw bulk RNA sequencing data was collected for the identification of nine survival-related APA events by multivariate Cox regression analysis and forward-selected Likelihood Ratio Test. They showed good prognosis ability on TNBC risk. Of them, the APA event in UBASH3B was proposed as a novel potential biomarker. This event disturbed microRNA regulation on its host gene and other competing tumor genes to possibly involve in the pathogenesis of TNBC.

bioinformatics↗

bioRxiv2022

PRMT5 links lipid metabolism to contractile function of skeletal muscles

The skeletal muscle plays a key role in systemic energy homeostasis besides its canonical contractile function, but what couples these functions is poorly defined. Protein Arginine MethylTransferase 5 (PRMT5) is a well-known oncoprotein but also expressed in healthy tissues with unclear physiological functions. As adult muscles express high levels of Prmt5, we generated myocyte-specific Prmt5 knockout (Prmt5MKO) mice. We observed reduced muscle mass, oxidative capacity, force production and exercise performance in Prmt5MKO mice. The motor deficiency is associated with scarce lipid droplets in myofibers due to defects in lipid biosynthesis and degradation. First, Prmt5MKO reduced demethylation and stability of Sterol Regulatory Element-Binding Transcription Factor 1a (SREBP1a), a master regulator of de novo lipogenesis. Second, Prmt5MKO impaired the repressive H4R3Me2s (histone H4 arginine-3 symmetric demethylation) at the Pnpla2 gene, elevating the level of its encoded protein ATGL, the rate-limiting enzyme catalyzing lipolysis. Accordingly, myocyte-specific double knockout of Pnpla2 and Prmt5 normalized muscle mass and function. Together, our findings delineate a physiological function of PRMT5 in linking lipid metabolism to contractile function of myofibers.

molecular biology↗

bioRxiv2022

Injectable polymer-nanoparticle hydrogel for the sustained intravitreal delivery of bimatoprost

Vision impairment resulting from chronic eye diseases, such as macular degeneration and glaucoma, severely impacts patients quality of life and poses an immense global financial burden. Current standard of care for such diseases includes daily eye drops or frequent intravitreal (ITV) injections, which are burdensome treatment modalities resulting in low patient compliance. There remains a growing need for easily administered long-acting delivery technologies for prolonging exposure of ocular therapeutics with each administration. Here, we deploy a supramolecular polymer-nanoparticle (PNP) hydrogel for ITV delivery of the glaucoma drug bimatoprost. PNP hydrogels are shear-thinning and self-healing, key properties for injectability, and enable slow release of molecular cargo in vitreous humor (VH) mimics. An in vivo study in New Zealand white rabbits demonstrated intravitreally injected PNP hydrogels form depots that degrade slowly over time, maintaining detectable levels of bimatoprost in the VH up to eight weeks following injection. Ophthalmic examinations and histopathology identified a mild foreign body response (FBR) to the hydrogel, characterized by rare clusters of foamy macrophages and giant cells associated with minimal, patchy fibroplasia. This work shows that PNP hydrogels exhibit numerous desirable traits for sustained drug delivery and further work will be necessary to optimize tolerability in the eye.

bioengineering↗

bioRxiv2022

Heterologous boost with mRNA vaccines against SARS-CoV-2 Delta/Omicron variants following an inactivated whole-virus vaccine

The coronavirus SARS-CoV-2 has mutated quickly and caused significant global damage. This study characterizes two mRNA vaccines ZSVG-02 (Delta) and ZSVG-02-O (Omicron BA.1), and associating heterologous prime-boost strategy following the prime of a most widely administrated inactivated whole-virus vaccine (BBIBP-CorV). The ZSVG-02-O induces neutralizing antibodies that effectively cross-react with Omicron subvariants following an order of BA.1>BA.2>BA.4/5. In naive animals, ZSVG-02 or ZSVG-02-O induce humoral responses skewed to the vaccines targeting strains, but cellular immune responses cross-react to all variants of concern (VOCs) tested. Following heterologous prime-boost regimes, animals present comparable neutralizing antibody levels and superior protection across all VOCs. Single-boost only generated ancestral and omicron dual-responsive antibodies, probably by "recall" and "reshape" the prime immunity. New Omicron-specific antibody populations, however, appeared only following the second boost with ZSVG-02-O. Overall, our results support a heterologous boost with ZSVG-02-O, providing the best protection against current VOCs in inactivated virus vaccine- primed populations.

molecular biology↗

bioRxiv2022

eIF3 mRNA selectivity profiling reveals eIF3k as a cancer-relevant regulator of ribosome content

eIF3, whose subunits are frequently overexpressed in cancer, regulates mRNA translation from initiation to termination, but mRNA-selective functions of individual subunits remain poorly defined. Using multi-omic profiling upon acute depletion of eIF3 subunits, we observed that while eIF3a, b, e, and f markedly differed in their impact on eIF3 holo-complex formation and translation, they were each required for cancer cell proliferation and tumor growth. Remarkably, eIF3k showed the opposite pattern with depletion promoting global translation, cell proliferation, tumor growth, and stress resistance through repressing the synthesis of ribosomal proteins, especially RPS15A. Whereas ectopic expression of RPS15A mimicked the anabolic effects of eIF3k depletion, disruption of eIF3 binding to the 5-UTR of RSP15A mRNA negated them. Supported by mathematical modeling, our data uncovers eIF3k-l as a mRNA-specific module which, through controlling RPS15A translation, serves as a rheostat of ribosome content to secure spare translational capacity that can be mobilized during stress.

cell biology↗

bioRxiv2022

Beta human papillomavirus 8E6 promotes alternative end-joining

Double strand breaks (DSBs) are one of the most lethal DNA lesions in cells. Previous studies show that the E6 protein of beta-human papillomavirus (HPV8 E6) impairs two major DSB repair pathways homologous recombination (HR) and non-homologous end-joining (NHEJ). However, HPV8 E6 delays but does not eliminate DSB repair capability of cells. How DSBs are repaired in cells with HPV8 E6 remains to be studied. We hypothesis that HPV8 E6 promotes a backup DSB repair pathway, alternative end-joining (Alt-EJ). Using CAS9 based Alt-EJ reporters, we show that HPV8 E6 promotes Alt-EJ. Further, using small molecule inhibitors, CRISPR/CAS9 gene knockout, and HPV8 E6 mutant, we find that HPV8 E6 promotes Alt-EJ by binding p300, an acetyltransferase that facilitates DSB repair by HR and NHEJ. Finally, we analyzed whole genome sequencing data from genomes of human foreskin keratinocytes expressing HPV8 E6 and found they displayed an increased frequency of deletions bearing the microhomology signatures of Alt-EJ. This study fills the knowledge gap how DSB is repaired in cells with HPV8 E6 and the mutagenic consequences of HPV8 E6 mediated p300 destabilization. Broadly, this study supports the hypothesis that beta-HPV promotes cancer formation by increasing genomic instability.

cancer biology↗

bioRxiv2022

Response of sugarcane rhizosphere soil fungal communities on a temporal gradient to changes in critical growth periods

Understanding the normal variation of the sugarcane rhizosphere fungal microbiota throughout its life cycle is essential for the development of agricultural practices for fungal diseases (e.g., sugarcane tip rot, sugarcane red rot, and sugarcane smut) and ecological health associated with the microbiota. Therefore, we performed high-throughput sequencing of 18S rDNA of soil samples using the Illumina sequencing platform for correlation analysis of sugarcane rhizosphere microbiota time series, covering information from 84 samples in four growth periods. The results revealed that the sugarcane rhizosphere fungi possessed the maximum fungal richness in July (Tillering). Rhizosphere fungi are closely associated with sugarcane growth, including Ascomycota, Basidiomycota, and Ochrophyta showed high abundance in a stage-specific manner. Through the Manhattan plots, 11 fungal genera were found to show a decreasing trend throughout the sugarcane growth period, and two fungal genera were significantly enriched at three stages of sugarcane growth (p < 0.05) including Pseudallescheria and Nectriaceae. In addition, soil pH, soil temperature (Tem), total nitrogen (TN) and total potassium (TP) were important drivers of fungal community structure at different stages of sugarcane growth. Using structural equation modeling (SEM) found that sugarcane disease status showed a significant and strong negative effect with selected soil properties, suggesting that poor soil may increase the likelihood of sugarcane disease. In addition changes in sugarcane rhizosphere community structure over time were mainly influenced by stochastic factors, but the contribution decreased to the lowest value after the sugarcane root adaptation system was stabilized (Maturity). IMPORTANCERhizosphere microbes are closely related to plant growth, and more studies have shown that the rhizosphere fungal microbial community has an important influence on plant health and growth status. However, little is known about the response of the rhizosphere fungal community to plant growth during the critical plant reproductive period. In this study, we analyzed the important response of the rhizosphere fungal community of sugarcane through the pattern of abundance changes in its critical growth nodes by various methods to investigate the subtle changes in the assembly of the rhizosphere fungal community with the growth of sugarcane. Our work provides innovative ideas for the prevention of soil-borne diseases in plants and also provides a solid basis for the development of microbial models of crops rhizosphere soil.

microbiology↗

bioRxiv2022

Intraoperative Spinal Cord Stimulation Mitigates Pain after Spine Surgery in Mice

BackgroundManaging postoperative pain after spine surgery is challenging, and up to 40% of operated patients develop failed back surgery syndrome (FBSS) resulting in intractable back and/or leg pain. While spinal cord stimulation (SCS) has been shown to effectively alleviate such chronic pain, it is unknown if intraoperative SCS can mitigate the development of central sensitization that potentially causes intense postoperative pain and FBSS after spine surgery. MethodsAs an experimental spine surgery, unilateral T13 laminectomy was performed in mice to expose the dorsal part of L4-5 spinal segments that receive sensory inputs from the hind limb. After the laminectomy, a group of mice received intraoperative SCS epidurally applied to the exposed side of the dorsal part of the spinal cord for an hour under anesthesia before closing the surgical wounds. Secondary mechanical hypersensitivity, a behavioral manifestation of central sensitization, was measured in hind paws using von Frey assay one day before and at predetermined times after surgery. In addition, because von Frey assay is a nocifensive reflex-based analysis that primarily assesses the sensory-discriminative domain of pain, we also performed a conflict avoidance test to capture the affective-motivational domain of pain at selected timepoints post-laminectomy. ResultsMice that underwent unilateral T13 laminectomy developed mechanical hypersensitivity in both hind paws, which gradually resolved in 1-2 weeks. The extent of the hypersensitivity was significantly less in the contralateral hind paw (relative to the laminectomy) than in the ipsilateral hind paw only in females. Intraoperative SCS applied to the exposed side of the dorsal -spinal cord significantly inhibited the development of hind paw mechanical hypersensitivity only in the SCS-applied side. When paws were mechanically stimulated in their preferred place to present a conflict between pain/discomfort and natural preference, mice avoided the conflict after laminectomy, spending less time in the place than before the surgery. However, mice treated with intraoperative SCS after laminectomy did not avoid the conflict. ConclusionThese results demonstrate that spine surgery for unilateral laminectomy induces central sensitization that results in postoperative pain hypersensitivity. Intraoperative SCS after laminectomy can mitigate the development of this hypersensitivity in the SCS-applied side.

neuroscience↗

bioRxiv2022

Aridity modulates biogeographic distribution and community assembly of cyanobacterial morphotypes in drylands

The patterns of biogeographical distribution and assembly processes of microbiota are of vital importance for understanding ecological adaptation and functioning maintenance that microorganisms provide. Although the assembly of microbial communities was increasingly inspected, the role of their morphological characteristics is still poorly ascertained. Here, by integrating high-throughput sequencing and traditional trait-based classification, we investigated taxonomic and phylogenetic turnovers of different morphotypes of terrestrial cyanobacteria in biocrusts, as a model system, to evaluate the contributions of deterministic and stochastic processes across a large scale in drylands. The results showed that the bundle-forming category dominated in arid ecosystems with high tolerance against environmental fluctuations. Despite strong distance-decay relationships of {beta}-diversity in all categories, both spatial composition and phylogenetic turnover rates of bundle-forming cyanobacteria were significantly lower than unicellular/colonial, heterocystous, and other non-heterocyst filamentous cyanobacteria. Null model analysis of phylogenetic signals and abundance-based neutral model found that stochastic processes prevailed in the assembly, while aridity mediated the balance between determinism and stochasticity and prompted a shifting threshold among morphotypes. Our findings provide a unique perspective to understand the role of microbial morphology, highlighting the differentiation of biogeographic distribution, environmental response, and species preference between morphotypes with consideration of potential functional consequences, and therefore facilitated the prediction of biodiversity loss under climate change.

ecology↗

bioRxiv2022

Suppression of tumor/host intrinsic CMTM6 drives anti-tumor cytotoxicity in a PD-L1 independent manner

CKLF-like MARVEL transmembrane domain-containing 6 (CMTM6) has been identified as a regulator of membranal programmed death ligand 1 (PD-L1) stability and a factor associated with malignancy progression, but the effects and mechanisms of CMTM6 on tumor growth, as well as its potential for therapy, are still largely unknown. Here, we show that tumor CMTM6 increased with progression in both clinical patients and mice. Ablation of CMTM6 resulted in significant retardation of human and murine tumor growth dependent on T-lymphocyte immunity. Tumor CMTM6 suppression broke resistance to immune checkpoint inhibitors and remodeled the tumor immune microenvironment, as specific antitumor cytotoxicity was enhanced and contributed primarily to tumor inhibition. Further, without the PD-1/PD-L1 axis, CMTM6 suppression still significantly dampened tumor growth dependent on cytotoxic cells. Notably, we identified that CMTM6 was widely expressed on immune cells. T-cell CMTM6 increased with sustained immune activation and intratumoral immune exhaustion and affected the T-cell-intrinsic PD-L1 levels. Host CMTM6 knockout significantly restrained tumor growth dependent on CD8+ T-cells, and similarly, not entirely dependent on PD-L1. Thus, we developed and evaluated the antitumor efficacy of CMTM6-targeting adeno-associated virus (AAV), which effectively mobilized antitumor immunity and could be combined with various antitumor drugs. Our findings reveal that both tumor and host CMTM6 are deeply involved in tumor immunity with or without the PD-1/PD-L1 axis and that gene therapy targeting CMTM6 is a promising strategy for cancer immunotherapy. One Sentence SummaryEven in the absence of the PD-1/PD-L1 axis, tumor or host CMTM6 deficiency can mediate cytotoxicity-dependent anti-tumor immune responses, allowing CMTM6 to be a novel target for scAAV-mediated oncoimmunology gene therapy and combination treatment.

immunology↗

bioRxiv2022

A cocktail containing two synergetic antibodies broadly neutralizes SARS-CoV-2 and its variants including Omicron BA.1 and BA.2

Neutralizing antibodies (NAbs) can prevent and treat infections caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). However, continuously emerging variants, such as Omicron, have significantly reduced the potency of most known NAbs. The selection of NAbs with broad neutralizing activities and the identification of conserved critical epitopes are still urgently needed. Here, we identified an extremely potent antibody (55A8) by single B-cell sorting from convalescent SARS-CoV-2-infected patients that recognized the receptor-binding domain (RBD) in the SARS-CoV-2 spike (S) protein. 55A8 could bind to wild-type SARS-CoV-2, Omicron BA.1 and Omicron BA.2 simultaneously with 58G6, a NAb previously identified by our group. Importantly, an antibody cocktail containing 55A8 and 58G6 (2-cocktail) showed synergetic neutralizing activity with a half-maximal inhibitory concentration (IC50) in the picomolar range in vitro and prophylactic efficacy in hamsters challenged with Omicron (BA.1) through intranasal delivery at an extraordinarily low dosage (25 g of each antibody daily) at 3 days post-infection. Structural analysis by cryo-electron microscopy (cryo-EM) revealed that 55A8 is a Class III NAb that recognizes a highly conserved epitope. It could block angiotensin-converting enzyme 2 (ACE2) binding to the RBD in the S protein trimer via steric hindrance. The epitopes in the RBD recognized by 55A8 and 58G6 were found to be different and complementary, which could explain the synergetic mechanism of these two NAbs. Our findings not only provide a potential antibody cocktail for clinical use against infection with current SARS-CoV-2 strains and future variants but also identify critical epitope information for the development of better antiviral agents.

immunology↗

bioRxiv2022

Spatial exploration of immune cell heterogeneity in skin functional scar-less wound regeneration model at single-cell resolution

Inevitable skin scarring devoid of dermal appendages bring about unfavorable effects on both aesthetic and physiological functions. Here we offered an available method for large-area wound regeneration using biodegradable Aligned extracellular matrix (ECM) scaffold. Accelerating wound coverage and enhanced hair follicle (HF) neogenesis were observed with the implantation of biomaterials. Multimodal analysis during wound regeneration provides a unique lens through which we can explore the foreign body responses (FBR) around biomaterials. First, we identified cell heterogeneity in responses to ECM scaffolds using single-cell RNA sequencing. Next the spatial anchor highlighted preferential recruitment of T cells around biomaterials colocalized with hair follicle precursor cells. Reconstruction of signaling pathways suggested the pro-regenerative effect of the adaptive immune systems on HF neogenesis. Immunodeficient mice lacking mature T lymphocytes lost the ability to activate papillary fibroblast as well as stimulate HF regeneration, validating the potential therapeutic effect of the adaptive immune system activated by biomaterials. In conclusion, this study provided the further understanding of the FBR and facilitate the design of immunoregulatory biomaterials for biomedical application in the future.

immunology↗

bioRxiv2022

Selective Control of Parasitic Nematodes Using Bioactivated Nematicides

Parasitic nematodes are a major threat to global food security, particularly as the world amasses 10 billion people amidst limited arable land. Most traditional nematicides have been banned due to poor nematode-selectivity, leaving farmers with inadequate controls. Here, we use the model nematode Caenorhabditis elegans to identify a family of selective imidazothiazole nematicides, called selectivins, that undergo cytochrome p450-dependent bioactivation exclusively in nematodes. At low parts-per-million concentrations, selectivins perform comparably well with commercial nematicides to control root infection by Meloidogyne incognita - the worlds most destructive plant-parasitic nematode. Tests against a wide range of phylogenetically diverse non-target systems demonstrate that selectivins are more nematode-selective than nearly all marketed nematicides. Thus, selectivins are first-in-class bioactivated nematode controls that provide efficacy as well as much-needed nematode selectivity.

pharmacology and toxicology↗

bioRxiv2022

Assessing base-resolution DNA mechanics on the genome scale

Intrinsic DNA properties such as bending play a crucial role in diverse biological systems. A recent advantage in the high-throughput method called loop-seq makes it possible to determine bendability of hundred thousand 50-bp DNA duplexes in one experiment. However, its still infeasible to assess whole sequence bendability in large genomes such as human, which needs thousands of loop-seq experiments. Here we introduce BendNet - a neural network to accurately predict the intrinsic DNA bending at base-resolution by only given DNA sequences. BendNet can increase the resolution of experimental results, and can predict DNA bendability for any new given sequences in high accuracy. We applied BendNet to the human genome and observed high-stiffness regions located at both transcriptional start sites and transcriptional end sites. Such stiffness patterns are different for coding and non-coding genes, which matches distinct nucleosome occupancy patterns. As expected, most transcription factors (TFs) bind in DNA of low bendability. In contrast, we observed an unusually high bendability within binding elements of specific TFs such as EBF1 and regulators of genome folding such as CTCF. These factors either co-bind or compete with nucleosomes to carry out their functions. More interestingly, CTCF binding regions exhibit the highest bendability than other DNA elements, implying their potential role in trapping and holding the CTCF in the exact locations to make sure CTCF as stable anchor in loop extrusion process. Our work provides a tool to assess DNA bendability for large-scale DNA sequences and expands our understanding on DNA mechanics in chromatin regulation and genome folding.

genomics↗

bioRxiv2021

Cell cycle stage classification using phase imaging with computational specificity

Traditional methods for cell cycle stage classification rely heavily on fluorescence microscopy to monitor nuclear dynamics. These methods inevitably face the typical phototoxicity and photobleaching limitations of fluorescence imaging. Here, we present a cell cycle detection workflow using the principle of phase imaging with computational specificity (PICS). The proposed method uses neural networks to extract cell cycle-dependent features from quantitative phase imaging (QPI) measurements directly. Our results indicate that this approach attains very good accuracy in classifying live cells into G1, S, and G2/M stages, respectively. We also demonstrate that the proposed method can be applied to study single-cell dynamics within the cell cycle as well as cell population distribution across different stages of the cell cycle. We envision that the proposed method can become a nondestructive tool to analyze cell cycle progression in fields ranging from cell biology to biopharma applications. TeaserWe present a non-destructive, high-throughput method for cell cycle detection combining label-free imaging and deep learning.

bioengineering↗

bioRxiv2021

Elevated transcriptional pausing of RNA polymerase II underlies acquired resistance to radiotherapy

As the mainstay modality for many malignancies, particularly inoperable solid tumors such as nasopharyngeal carcinoma (NPC), ionizing radiation (IR) induces a variety of lesions in genomic DNA, evoking a multipronged DNA damage response to interrupt many cellular processes including transcription. The turbulence in transcription, depending on the nature of DNA lesions, encompasses local blockage of RNA polymerase II (RNAPII) near the damage sites, as well as a less understood genome-wide alteration. How the transcriptional change influences the effectiveness of radiotherapy remains unclear. Using a panel of NPC and lung cancer cell lines, we observe increased phosphorylation at serine 5 (pS5) of the RNAPII after IR, indicating an accumulation of paused RNAPII. Remarkably, a similar increase of pS5 is seen in IR-resistant cells. ChIP-seq analysis of RNAPII distribution confirms this increased pausing both in IR-treated and IR-resistant NPC cells, notably on genes involved in radiation response and cell cycle. Accordingly, many of these genes show downregulated transcripts abundance in IR-resistant cells, and individual knockdown some of them such as TP53 and NEK7 endows NPC cells with varying degrees of IR-resistance. Decreasing pS5 of RNAPII and hence tuning down transcriptional pausing by inhibiting CDK7 reverses IR-resistance both in cell culture and xenograft models. Our results therefore uncover an unexpected link between elevated transcriptional pausing and IR-resistance. Given the recurrent NPC tissues display a steady increase in pS5 compared to the paired primary tissues, we suggest that CDK7 inhibitors can be used in combination with radiotherapy to increase sensitivity and thwart resistance.

cancer biology↗