RAS P21 Protein Activator 3 (RASA3) Specifically Promotes Pathogenic T Helper 17 Cell Generation by Repressing T-Helper-2-Cell-Biased Programs.

Pathogenic Th17 (pTh17) cells drive inflammation and immune-pathology, but whether pTh17 cells are a Th17 cell subset whose generation is under specific molecular control remains unaddressed. We found that Ras p21 protein activator 3 (RASA3) was highly expressed by pTh17 cells relative to non-pTh17 cells and was required specifically for pTh17 generation in vitro and in vivo. Mice conditionally deficient for Rasa3 in T cells showed less pathology during experimental autoimmune encephalomyelitis. Rasa3-deficient T cells acquired a Th2 cell-biased program that dominantly trans-suppressed pTh17 cell generation via interleukin 4 production. The Th2 cell bias of Rasa3-deficient T cells was due to aberrantly elevated transcription factor IRF4 expression. RASA3 promoted proteasome-mediated IRF4 protein degradation by facilitating interaction of IRF4 with E3-ubiquitin ligase Cbl-b. Therefore, a RASA3-IRF4-Cbl-b pathway specifically directs pTh17 cell generation by balancing reciprocal Th17-Th2 cell programs. These findings indicate that a distinct molecular program directs pTh17 cell generation and reveals targets for treating pTh17 cell-related pathology and diseases.

Nucleolin Malonylation as a Nuclear-Cytosol Signal Exchange Mechanism to Drive Cell Proliferation in Hepatocarcinoma by Enhancing AKT Translation.

Cancer cells undergo metabolic reprogramming that is intricately linked to malignancy. Protein acylations are especially responsive to metabolic changes, influencing signal transduction pathways and fostering cell proliferation. However, as a novel type of acylations, the involvement of malonylation in cancer remains poorly understood. In this study, we observed a significant reduction in malonyl-CoA levels in hepatocellular carcinoma (HCC), which correlated with a global decrease in malonylation. Subsequent nuclear malonylome analysis unveiled nucleolin (NCL) malonylation, which was notably enhanced in HCC biopsies. we demonstrated that NCL undergoes malonylation at lysine residues 124 and 398. This modification triggers the translocation of NCL from the nucleolus to nucleoplasm and cytoplasm, binding to AKT mRNA, and promoting AKT translation in HCC. Silencing AKT expression markedly attenuated HCC cell proliferation driven by NCL malonylation. These findings collectively highlight nuclear signaling in modulating AKT expression, suggesting NCL malonylation as a novel mechanism through which cancer cells drive cell proliferation.

In vivo manufacture and manipulation of CAR-T cells for better druggability.

The current CAR-T cell therapy products have been hampered in their druggability due to the personalized preparation required, unclear pharmacokinetic characteristics, and unpredictable adverse reactions. Enabling standardized manufacturing and having clear efficacy and pharmacokinetic characteristics are prerequisites for ensuring the effective practicality of CAR-T cell therapy drugs. This review provides a broad overview of the different approaches for controlling behaviors of CAR-T cells in vivo. The utilization of genetically modified vectors enables in vivo production of CAR-T cells, thereby abbreviating or skipping the lengthy in vitro expansion process. By equipping CAR-T cells with intricately designed control elements, using molecule switches or small-molecule inhibitors, the control of CAR-T cell activity can be achieved. Moreover, the on-off control of CAR-T cell activity would yield potential gains in phenotypic remodeling. These methods provide beneficial references for the future development of safe, controllable, convenient, and suitable for standardized production of CAR-T cell therapy products.

Inhibition of human adenovirus replication by TRIM35-mediated degradation of E1A.

Human adenovirus (HAdV) is ubiquitous in the human population, constituting a significant burden of global respiratory diseases. Children and individuals with low immunity are at risk of developing severe infections without approved antiviral treatment for HAdV. Our study demonstrated that TRIM35 inhibited HAdV-C5 early gene transcription, early protein expression, genome replication, and infectious virus progeny production. Furthermore, TRIM35 was found to inhibit HAdV replication by attenuating E1A expression. Mechanistically, TRIM35 interacts with and degrades E1A by promoting its K48-linked ubiquitination. Additionally, K253 and K285 are the key sites necessary for TRIM35 degradation. Moreover, an oncolytic adenovirus carrying shTRIM35 was constructed and observed to exhibit improved oncolysis in vivo, providing new ideas for clinical tumor treatment. Our results expand the broad antiviral activity of TRIM35 and mechanically support its application as a HAdV replication inhibitor. IMPORTANCE E1A is an essential human adenovirus (HAdV) protein responsible for the early replication of adenovirus while interacting with multiple host proteins. Understanding the interaction between HAdV E1A and TRIM35 helps identify effective antiviral therapeutic targets. The viral E1A protein is a crucial activator and regulator of viral transcription during the early infection stages. We first reported that TRIM35 interacts with E1A to resist adenovirus infection. Our study demonstrated that TRIM35 targets E1A to resist adenovirus, indicating the applicability of targeting virus-dependent host factors as a suitable antiviral strategy.

Efficacy and safety of CD19-specific CAR T cell-based therapy in B-cell acute lymphoblastic leukemia patients with CNSL.

Few studies have described chimeric antigen receptor (CAR) T-cell therapy for patients with B-cell acute lymphoblastic leukemia (B-ALL) with central nervous system leukemia (CNSL) because of concerns regarding poor response and treatment-related neurotoxicity. Our study included 48 patients with relapsed/refractory B-ALL with CNSL to evaluate the efficacy and safety of CD19-specific CAR T cell-based therapy. The infusion resulted in an overall response rate of 87.5% (95% confidence interval [CI], 75.3-94.1) in bone marrow (BM) disease and remission rate of 85.4% (95% CI, 72.8-92.8) in CNSL. With a median follow-up of 11.5 months (range, 1.3-33.3), the median event-free survival was 8.7 months (95% CI, 3.7-18.8), and the median overall survival was 16.0 months (95% CI, 13.5-20.1). The cumulative incidences of relapse in BM and CNS diseases were 31.1% and 11.3%, respectively, at 12 months (P = .040). The treatment was generally well tolerated, with 9 patients (18.8%) experiencing grade ≥3 cytokine release syndrome. Grade 3 to 4 neurotoxic events, which developed in 11 patients (22.9%), were associated with a higher preinfusion disease burden in CNS and were effectively controlled under intensive management. Our results suggest that CD19-specific CAR T cell-based therapy can induce similar high response rates in both BM and CNS diseases. The duration of remission in CNSL was longer than that in BM disease. CD19 CAR T-cell therapy may provide a potential treatment option for previously excluded patients with CNSL, with manageable neurotoxicity. The clinical trials were registered at www.clinicaltrials.gov as #NCT02782351 and www.chictr.org.cn as #ChiCTR-OPN-16008526.

Comprehensive characterization of cytopenia after chimeric antigen receptor-T cell infusion in patients with relapsed or refractory multiple myeloma.

BACKGROUND: Many studies have demonstrated the effectiveness of chimeric antigen receptor-T (CAR-T) cell therapy for relapsed or refractory multiple myeloma (RRMM), but the hematologic toxicity has not been well characterized. METHODS: A total of 111 adults with RRMM who received BCMA CAR-T cells, BCMA + CD19 CAR-T cells or tandem BCMA/CD19 dual-target (BC19) CAR-T cells infusion were enrolled. We characterized cytopenia and hematologic recovery at different time points after CAR-T-cell therapy, analyzed the effect of cytopenia on prognosis and identified the risk factors. RESULTS: Patients had a high probability of cytopenia, with anemia, neutropenia and thrombocytopenia occurring in 92%, 95% and 73%, respectively. There were 60 (54%) patients had prolonged hematologic toxicity (PHT) after D28. The median hemoglobin and platelet count were significantly lower at D28 post-CAR-T cell therapy than at baseline. Hemoglobin increased to above baseline at D90. The median absolute neutrophil count was lower than baseline at D0 and D28, and it recovered to baseline at D180. The baseline level of lactate dehydrogenase was associated with thrombocytopenia. Extramedullary involvement was associated with hemoglobin recovery, while the baseline level of albumin and types of CAR-T were related to platelet recovery. Patients with anemia at baseline and at D0, D180 and D360 had shorter progression-free survival (PFS), while anemia at D0, D60, D180 and D360 was associated with shorter overall survival (OS). Neutropenia at D0 was associated with shorter PFS and patients with neutropenia at D90 or D180 had shorter OS. Patients with thrombocytopenia at any time had shorter PFS and OS. Compared to patients without PHT, patients with PHT had shorter PFS and OS. CONCLUSIONS: The majority of RRMM patients treated with CAR-T cells experienced cytopenia. Cytopenia occurred at specific time points was associated with a poorer prognosis.

Complex association of body mass index and outcomes in patients with relapsed and refractory multiple myeloma treated with CAR-T cell immunotherapy.

BACKGROUND AIMS: Chimeric antigen receptor-T (CAR-T) cells have exhibited remarkable efficacy in treating refractory or relapsed multiple myeloma (R/R MM). Although obesity has a favorable value in enhancing the response to immunotherapy, less is known about its predictive value regarding the efficacy and prognosis of CAR-T cell immunotherapy. METHODS: We conducted a retrospective study of 111 patients with R/R MM who underwent CAR-T cell treatment. Using the body mass index (BMI) classification, the patients were divided into a normal-weight group (73/111) and an overweight group (38/111). We investigated the effect of BMI on CAR-T cell therapy outcomes in patients with R/R MM. RESULTS: The objective remission rates after CAR-T cell infusion were 94.7% and 89.0% in the overweight and normal-weight groups, respectively. The duration of response and overall survival were not significant difference between BMI groups. Compared to normal-weight patients, overweight patients had an improved median progression-free survival. There was no significant difference in cytokine release syndrome and immune effector cell-associated neurotoxicity syndrome between the subgroups. In terms of hematological toxicity, the erythrocyte, hemoglobin, platelet, leukocyte and neutrophil recovery was accelerated in the overweight group. Fewer patients in the overweight group displayed moderate percent CD4 and CD4/CD8 ratios compared to the normal-weight group. Furthermore, the percent CD4 ratios were positively correlated with the levels of cytokines [interleukin-2 (IL-2) (day 14), interferon gamma (IFN-γ) (day 7) and tumor necrosis factor alpha (TNF-α) (days 14 and 21)] after cells infusion. On the other hand, BMI was positively associated with the levels of IFN-γ (day 7) and TNF-α (days 14 and 21) after CAR-T cells infusion. CONCLUSIONS: Overall, this study highlights the potential beneficial effect of a higher BMI on CAR-T cell therapy outcomes.

Expand available targets for CAR-T therapy to overcome tumor drug resistance based on the "Evolutionary Traps".

Based on the concept of "Evolutionary Traps", targeting survival essential genes obtained during tumor drug resistance can effectively eliminate resistant cells. While, it still faces limitations. In this study, lapatinib-resistant cells were used to test the concept of "Evolutionary Traps" and no suitable target stand out because of the identified genes without accessible drug. However, a membrane protein PDPN, which is low or non-expressed in normal tissues, is identified as highly expressed in lapatinib-resistant tumor cells. PDPN CAR-T cells were developed and showed high cytotoxicity against lapatinib-resistant tumor cells in vitro and in vivo, suggesting that CAR-T may be a feasible route for overcoming drug resistance of tumor based on "Evolutionary Trap". To test whether this concept is cell line or drug dependent, we analyzed 21 drug-resistant tumor cell expression profiles reveal that JAG1, GPC3, and L1CAM, which are suitable targets for CAR-T treatment, are significantly upregulated in various drug-resistant tumor cells. Our findings shed light on the feasibility of utilizing CAR-T therapy to treat drug-resistant tumors and broaden the concept of the "Evolutionary Trap".

Clinical outcomes and microenvironment profiling in relapsed/refractory multiple myeloma patients with extramedullary disease receiving anti-BCMA CAR T-cell-based therapy.

Relapsed/refractory multiple myeloma patients with extramedullary disease (EMD) have unfavorable prognosis and lack effective therapy. Chimeric antigen receptor (CAR) T-cell activities in EMD have yet to be determined; how EMD-specific microenvironment influences the clinical outcomes of CAR T-cell therapy remains of great interest. In this prospective cohort study, patients with histologically confirmed extra-osseous EMD were enrolled and treated with combined anti-BCMA and anti-CD19 CAR T-cell therapy from May 2017 to September 2023. Thirty-one patients were included in the study. Overall response occurred in 90.3% of medullary disease and 64.5% of EMD (p = .031). Discrepancies in treatment response were noted between medullary and extramedullary diseases, with EMD exhibiting suboptimal and delayed response, as well as shortened response duration. With a median follow-up of 25.3 months, the median progression-free and overall survival were 5.0 and 9.7 months, respectively. Landmark analysis demonstrated that progression within 6 months post-infusion is strongly associated with an increased risk of death (HR = 4.58; p = .029). Compared with non-EMD patients, patients with EMD showed inferior survival outcomes. Unique CAR-associated local toxicities at EMD were seen in 22.6% patients and correlated with the occurrence and severity of systemic cytokine release syndrome. To the cutoff date, 65% treated patients experienced EMD progression, primarily in the form of BCMA+ progression. The pretherapy EMD immunosuppressive microenvironment, characterized by infiltration of exhausted CD8+ T cells, was associated with inferior clinical outcomes. CAR T cells have therapeutic activity in relapsed/refractory EMD, but the long-term survival benefits may be limited. EMD-specific microenvironment potentially impacts treatment. Further efforts are needed to extend EMD remission and improve long-term outcomes.

GBDT_KgluSite: An improved computational prediction model for lysine glutarylation sites based on feature fusion and GBDT classifier.

BACKGROUND: Lysine glutarylation (Kglu) is one of the most important Post-translational modifications (PTMs), which plays significant roles in various cellular functions, including metabolism, mitochondrial processes, and translation. Therefore, accurate identification of the Kglu site is important for elucidating protein molecular function. Due to the time-consuming and expensive limitations of traditional biological experiments, computational-based Kglu site prediction research is gaining more and more attention. RESULTS: In this paper, we proposed GBDT_KgluSite, a novel Kglu site prediction model based on GBDT and appropriate feature combinations, which achieved satisfactory performance. Specifically, seven features including sequence-based features, physicochemical property-based features, structural-based features, and evolutionary-derived features were used to characterize proteins. NearMiss-3 and Elastic Net were applied to address data imbalance and feature redundancy issues, respectively. The experimental results show that GBDT_KgluSite has good robustness and generalization ability, with accuracy and AUC values of 93.73%, and 98.14% on five-fold cross-validation as well as 90.11%, and 96.75% on the independent test dataset, respectively. CONCLUSION: GBDT_KgluSite is an effective computational method for identifying Kglu sites in protein sequences. It has good stability and generalization ability and could be useful for the identification of new Kglu sites in the future. The relevant code and dataset are available at https://github.com/flyinsky6/GBDT_KgluSite .

Mitochondrial C1QBP is essential for T cell antitumor function by maintaining mitochondrial plasticity and metabolic fitness.

The metabolic stress present in the tumor microenvironment of many cancers can attenuate T cell antitumor activity, which is intrinsically controlled by the mitochondrial plasticity, dynamics, metabolism, and biogenesis within these T cells. Previous studies have reported that the complement C1q binding protein (C1QBP), a mitochondrial protein, is responsible for maintenance of mitochondrial fitness in tumor cells; however, its role in T cell mitochondrial function, particularly in the context of an antitumor response, remains unclear. Here, we show that C1QBP is indispensable for T cell antitumor immunity by maintaining mitochondrial integrity and homeostasis. This effect holds even when only one allele of C1qbp is functional. Further analysis of C1QBP in the context of chimeric antigen receptor (CAR) T cell therapy against the murine B16 melanoma model confirmed the cell-intrinsic role of C1QBP in regulating the antitumor functions of CAR T cells. Mechanistically, we found that C1qbp knocking down impacted mitochondrial biogenesis via the AMP-activated protein kinase (AMPK)/peroxisome proliferator-activated receptor gamma coactivator 1-alpha signaling pathway, as well as mitochondrial morphology via the phosphorylation of mitochondrial dynamics protein dynamin-related protein 1. In summary, our study provides a novel mitochondrial target to potentiate the plasticity and metabolic fitness of mitochondria within T cells, thus improving the immunotherapeutic potential of these T cells against tumors.

GSK3326595 is a promising drug to prevent SARS-CoV-2 Omicron and other variants infection by inhibiting ACE2-R671 di-methylation.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) caused COVID-19 epidemic is worsening. Binding of the Spike1 protein of SARS-CoV-2 with the angiotensin-converting enzyme 2 (ACE2) receptor mediates entry of the virus into host cells. Many reports show that protein arginine methylation by protein arginine methyltransferases (PRMTs) is important for the functions of these proteins, but it remains unclear whether ACE2 is methylated by PRMTs. Here, we show that PRMT5 catalyses ACE2 symmetric dimethylation at residue R671 (meR671-ACE2). We indicate that PRMT5-mediated meR671-ACE2 promotes SARS-CoV-2 receptor-binding domain (RBD) binding with ACE2 probably by enhancing ACE2 N-glycosylation modification. We also reveal that the PRMT5-specific inhibitor GSK3326595 is able to dramatically reduce ACE2 binding with RBD. Moreover, we discovered that meR671-ACE2 plays an important role in ACE2 binding with Spike1 of the SARS-CoV-2 Omicron, Delta, and Beta variants; and we found that GSK3326595 strongly attenuates ACE2 interaction with Spike1 of the SARS-CoV-2 Omicron, Delta, and Beta variants. Finally, SARS-CoV-2 pseudovirus infection assays uncovered that PRMT5-mediated meR671-ACE2 is essential for SARS-CoV-2 infection in human cells, and pseudovirus infection experiments confirmed that GSK3326595 can strongly suppress SARS-CoV-2 infection of host cells. Our findings suggest that as a clinical phase II drug for several kinds of cancers, GSK3326595 is a promising candidate to decrease SARS-CoV-2 infection by inhibiting ACE2 methylation and ACE2-Spike1 interaction.

Associations of granulocyte colony-stimulating factor with toxicities and efficacy of chimeric antigen receptor T-cell therapy in relapsed or refractory multiple myeloma.

BACKGROUND AIMS: Few studies have reported the associations of granulocyte colony-stimulating factor (G-CSF) with cytokine release syndrome (CRS), neurotoxic events (NEs) and efficacy after chimeric antigen receptor (CAR) T-cell therapy for relapsed or refractory (R/R) multiple myeloma (MM). We present a retrospective study performed on 113 patients with R/R MM who received single anti-BCMA CAR T-cell, combined with anti-CD19 CAR T-cell or anti-CD138 CAR T-cell therapy. METHODS: Eight patients were given G-CSF after successful management of CRS, and no CRS re-occurred thereafter. Of the remaining 105 patients that were finally analyzed, 72 (68.6%) received G-CSF (G-CSF group), and 33 (31.4%) did not (non G-CSF group). We mainly analyzed the incidence and severity of CRS or NEs in two groups of patients, as well as the associations of G-CSF timing, cumulative dose and cumulative time with CRS, NEs and efficacy of CAR T-cell therapy. RESULTS: Both groups of patients had similar duration of grade 3-4 neutropenia, and the incidence and severity of CRS or NEs.There were also no differences in the incidence and severity of CRS or NEs between patients with the timing of G-CSF administration ≤3 days and those >3 days after CAR T-cell infusion. The incidence of CRS was greater in patients receiving cumulative doses of G-CSF >1500 µg or cumulative time of G-CSF administration >5 days. Among patients with CRS, there was no difference in the severity of CRS between patients who used G-CSF and those who did not. The duration of CRS in anti-BCMA and anti-CD19 CAR T-cell-treated patients was prolonged after G-CSF administration. There were no significant differences in the overall response rate at 1 and 3 months between the G-CSF group and the non-G-CSF group. CONCLUSIONS: Our results showed that low-dose or short-time use of G-CSF was not associated with the incidence or severity of CRS or NEs, and G-CSF administration did not influence the antitumor activity of CAR T-cell therapy.

Oncolytic adenovirus-mediated expression of CCL5 and IL12 facilitates CA9-targeting CAR-T therapy against renal cell carcinoma.

Chimeric antigen receptor T-cell (CAR-T) is particularly prominent in hematological but not in solid tumors, mainly based on the complex tumor immune microenvironment. Oncolytic virus (OVs) is an emerging adjuvant therapy method. OVs may prime tumor lesions to induce anti-tumor immune response, thereby enhancing CAR-T cells functionality and possibly increasing response rates. Here, we combined CAR-T cells targeting carbonic anhydrase 9 (CA9) and an oncolytic adenovirus (OAV) carrying chemokine (C-C motif) ligand 5 (CCL5), cytokine interleukin-12 (IL12) to explore the anti-tumor effects of this combination strategy. The data showed that Ad5-ZD55-hCCL5-hIL12 could infect and replicate in renal cancer cell lines and induced a moderate inhibition of xenografted tumor in nude mice. IL12 mediated by Ad5-ZD55-hCCL5-hIL12 promoted the phosphorylation of Stat4 in CAR-T cells, induced CAR-T cells to secrete more IFN-γ. We also found that Ad5-ZD55-hCCL5-hIL-12 combined with CA9-CAR-T cells significantly increased the infiltration of CAR-T cells in tumor mass, prolonged the survival of the mice and restrained tumor growth in immunodeficient mice. Ad5-ZD55-mCCL5-mIL-12 could also increase CD45+CD3+T cell infiltration and prolong mice survival in immunocompetent mice. These results provided feasibility for the combination of oncolytic adenovirus and CAR-T cells, which demonstrated the sufficient potential and prospects of CAR-T for the treatment of solid tumors.

SHMT2 promotes the tumorigenesis of renal cell carcinoma by regulating the m6A modification of PPAT.

OBJECTIVE: Serine hydroxymethyltransferase 2 (SHMT2) is the first rate-limiting enzyme for serine/glycine biosynthesis and one carbon metabolism. Here, we explore the underlying mechanism of how SHMT2 functions in renal cell carcinoma (RCC) initiation. METHODS: In this study, SHMT2 expression was assessed in RCC tissues. In vitro experiments were performed to investigate the functional role of SHMT2. The detailed mechanisms of SHMT2-mediated PPAT were addressed. RESULTS: Increased SHMT2 facilitated RCC cell proliferation by inducing the G1/S phase transition. And SHMT2 promoted the expression of PPAT. Mechanism dissection revealed that SHMT2 enhanced the m6A modification through the endogenous methyl donor SAM mediated by SHMT2 via serine/glycine one carbon metabolic networks. SHMT2-catalyzed serine/glycine conversion regulated PPAT expression in an m6A-IGF2BP2-dependent manner. SHMT2 promoted RCC cell proliferation by upregulating PPAT expression. CONCLUSIONS: SHMT2 promotes RCC tumorigenesis by increasing PPAT expression. Thus, SHMT2 may be a novel potential therapeutic target for RCC.

FAP-α-Instructed Coumarin Excimer Formation for High Contrast Fluorescence Imaging of Tumor.

Emissive excimers, which are formed by planar polycyclic aromatic fluorophores (e.g., coumarin), enable high contrast tumor imaging. However, it is still challenging to "turn on" excimer fluorescence in physiological dilute solutions. The biocompatible CBT-Cys click condensation reaction enables both intra- and intermolecular aggregations of the as-loaded fluorophores on the probe molecules, which may promote the generation of emissive excimers in a synergistic manner. As a proof-of-concept, we herein design a fluorescence probe Cbz-Gly-Pro-Cys(StBu)-Lys(coumarin)-CBT (Cbz-GPC(StBu)K(Cou)-CBT), which can be activated by FAP-α under tumor-inherent reduction conditions, undergo a CBT-Cys click reaction, and self-assemble into coumarin nanoparticle Cou-CBT-NP to "turn on" the excimer fluorescence. In vitro and in vivo studies validate that this "smart" probe realizes efficient excimer fluorescence imaging of FAP-α-overexpressed tumor cells with high contrast and enhanced accumulation, respectively. We anticipate that this probe can be applied for diagnosis of FAP-α-related diseases in the clinic in near future.

Prostate cancer liver metastasis: Dormancy and resistance to therapy.

Liver metastasis causes nearly half of death from solid tumors. Metastatic lesions, to the liver in particular, can become detectable years or decades after primary tumor removal, leaving an uncertain long-term prognosis in patients. Prostate cancer (PCa), a prominent metastatic dormant cancer, has the worst prognosis when found in the liver compared to other metastatic sites. These metastatic nodules display a therapy resistance in the liver pro-metastatic microenvironment; the resistance appears to be conferred by both dormancy and independent of dormancy when the nodules emerge. Within the review, the molecular underpinnings of how the liver aids and protects PCa cells seeding, colonization and resistance will be discussed.

Expanding uncapped translation and emerging function of circular RNA in carcinomas and noncarcinomas.

Circular RNAs (circRNAs) are classified as noncoding RNAs because they are devoid of a 5' end cap and a 3' end poly (A) tail necessary for cap-dependent translation. However, increasing numbers of translated circRNAs identified through high-throughput RNA sequencing overlapping with polysome profiling indicate that this rule is being broken. CircRNAs can be translated in cap-independent mechanism, including IRES (internal ribosome entry site)-initiated pattern, MIRES (m6A internal ribosome entry site) -initiated patterns, and rolling translation mechanism (RCA). CircRNA-encoded proteins harbour diverse functions similar to or different from host proteins. In addition, they are linked to the modulation of human disease including carcinomas and noncarcinomas. CircRNA-related translatomics and proteomics have attracted increasing attention. This review discusses the progress and exclusive characteristics of circRNA translation and highlights the latest mechanisms and regulation of circRNA translatomics. Furthermore, we summarize the extensive functions and mechanisms of circRNA-derived proteins in human diseases, which contribute to a better understanding of intricate noncanonical circRNA translatomics and proteomics and their therapeutic potential in human diseases.

Complement C1q binding protein regulates T cells' mitochondrial fitness to affect their survival, proliferation, and anti-tumor immune function.

T cells survival, proliferation, and anti-tumor response are closely linked to their mitochondrial health. Complement C1q binding protein (C1QBP) promotes mitochondrial fitness through regulation of mitochondrial metabolism and morphology. However, whether C1QBP regulates T cell survival, proliferation, and anti-tumor immune function remains unclear. Our data demonstrated that C1QBP knockdown induced the accumulation of reactive oxygen species (ROS) and the loss of mitochondrial membrane potential to impair T cell mitochondrial fitness. At the same time, C1QBP insufficiency reduced the recruitment of the anti-apoptotic proteins, including Bcl-2 and Bcl-XL, and repressed caspase-3 activation and poly (ADP-ribose) polymerase cleavage, which consequently accelerated the T cell apoptotic process. In contrast, C1QBP knockdown rendered T cells with relatively weaker proliferation due to the inhibition of AKT/mTOR signaling pathway. To investigate the exact role of C1QBP in anti-tumor response, C1QBP+/- and C1QBP+/+ mice were given a subcutaneous injection of murine MC38 cells. We found that C1QBP deficiency attenuated T cell tumor infiltration and aggravated tumor-infiltrating T lymphocytes (TIL) exhaustion. Moreover, we further clarified the potential function of C1QBP in chimeric antigen receptor (CAR) T cell immunotherapy. Our data showed that C1QBP+/- CAR T cells exhibited relatively weaker anti-tumor response than the corresponding C1QBP+/+ CAR T cells. Given that C1QBP knockdown impairs T cells' anti-apoptotic capacity, proliferation as well as anti-tumor immune function, development of the strategy for potentiation of T cells' mitochondrial fitness through C1QBP could potentially optimize the efficacy of the related immunotherapy.

Identification of a small-molecule RPL11 mimetic that inhibits tumor growth by targeting MDM2-p53 pathway.

BACKGROUND: Targeting ribosome biogenesis to activate p53 has recently emerged as a therapeutic strategy in human cancer. Among various ribosomal proteins, RPL11 centralizes the nucleolar stress-sensing pathway by binding MDM2, leading to MDM2 inactivation and p53 activation. Therefore, the identification of MDM2-binding RPL11-mimetics would be valuable for anti-cancer therapeutics. METHODS: Based on the crystal structure of the interface between RPL11 and MDM2, we have identified 15 potential allosteric modulators of MDM2 through the virtual screening. RESULTS: One of these compounds, named S9, directly binds MDM2 and competitively inhibits the interaction between RPL11 and MDM2, leading to p53 stabilization and activation. Moreover, S9 inhibits cancer cell proliferation in vitro and in vivo. Mechanistic study reveals that MDM2 is required for S9-induced G2 cell cycle arrest and apoptosis, whereas p53 contributes to S9-induced apoptosis. CONCLUSIONS: Putting together, S9 may serve as a lead compound for the development of an anticancer drug that specifically targets RPL11-MDM2-p53 pathway.