Corrigendum: OIT3 serves as a novel biomarker of hepatocellular carcinoma by mediating ferroptosis via regulating the arachidonic acid metabolism.

[This corrects the article DOI: 10.3389/fonc.2022.977348.].

OIT3 serves as a novel biomarker of hepatocellular carcinoma by mediating ferroptosis via regulating the arachidonic acid metabolism.

Background: Oncoprotein-Induced Transcript 3 Protein (OIT3) was identified as a liver-specific gene with abnormal expression in hepatocellular carcinoma (HCC). Herein, we aimed to examine the function and specific mechanism of OIT3 in HCC. Methods: Bioinformatic analyses and tissue microarray via immunohistochemistry were used to validate the expression of OIT3 in HCC. The biofunctions of OIT3 in HCC were determined in vitro and in vivo. The mechanism was confirmed by RNA-Sequence and Western blotting. The uni- and multivariate analyses were used to identify the independent predictors for HCC. Results: Low expression of OIT3 was observed in HCC and predicted a poor clinical outcome. Ectopic expression of OIT3 could inhibit the proliferation, migration, and invasion abilities of HCC cells. Mechanistically, OIT3 upregulated the expression of ALOX15 and CYP4F3, thus inducing arachidonic acid increase, ROS accumulation, and lipid peroxidation, and eventually causing ferroptosis. OIT3 was validated as a prognostic predictor for HCC patients. Conclusions: Our findings revealed a novel role of OIT3 in the process of tumorigenesis of HCC. OIT3 inhibited reproliferation, migration, and invasion of HCC cells by triggering ferroptosis, which indicates that OIT3 could serve as a potential biomarker in HCC.

The circadian clock sets a spatial-temporal window for recent thymic emigrants.

The diurnal timing system regulates multiple functions of lymphocytes in peripheral lymphoid organs. Whether T-cell development in the thymus and T-cell egress from the thymus are affected by the circadian clock is not clear. Herein, we used flow cytometry to examine the cell number and percentage of total thymocytes and various thymocyte subsets from Zeitgeber time (ZT) 1 to ZT21. CD4 and CD8 single-positive (SP) thymocytes, in particular, the mature CD4 SP4 thymocyte subset with emigration capability and P-phycoerythrin+ CD4 SP thymocytes in the perivascular space of the thymus, exhibited robust circadian oscillations. The diurnal expression of sphingosine-1-phosphate receptor-1 (S1PR1) and CCR2 on SP thymocytes and the rhythmic sphingosine-1-phosphate (S1P) and CCL2 gradient formed between peripheral blood and thymus likely promoted SP thymocyte egress in a circadian pattern. Switching the daylight cycle disturbed the rhythm of S1PR1 and CCR2 expression and subsequent thymocyte output. We further demonstrated that the core clock molecule BMAL1 had rhythmic binding of the promoters of Klf2, S1pr1 and Sphk2. Together, we elucidated the circadian dynamic characteristics of mature thymocyte egress, which coordinated with the diurnal changes in T-cell homing to the lymph nodes. The core rhythmic molecule BMAL1 likely promoted thymocyte emigration through transcriptional regulation of emigration-related molecules.

Clinical Experience and Management Strategy of Retroperitoneal Tumor With Venous Tumor Thrombus Involvement.

Background: This study aims to report the surgical management, complications, and outcomes for patients with retroperitoneal tumor and venous thrombus. Methods: We retrospectively analyzed 19 cases of retroperitoneal tumor with venous tumor thrombus from August 2015 to March 2021. A new tumor thrombus PUTH-RT grading system was proposed on the basis of the characteristics of the surgical techniques. Results: Two cases of PUTH-RT-1a, two cases of PUTH-RT-1b, six cases of PUTH-RT-2, six cases of PUTH-RT-3, and three cases of PUTH-RT-4 were included. Surgeries were successfully performed in all 19 patients. Among them, five cases (26.3%) were operated via a completely laparoscopic approach and 13 cases (68.4%) via an open approach. One case (5.3%) was converted from laparoscopic to open approach. Five cases (26.3%) experienced postoperative complications. All patients were followed for a median of 14 months. Cancer-associated death occurred in three cases. Distant metastases occurred in seven cases. Conclusions: We propose a new tumor thrombus grading system based on the anatomical characteristics of retroperitoneal tumors with venous tumor thrombus. Retroperitoneal tumor resection and removal of venous tumor thrombi are safe and effective for the treatment of such diseases.

Clinicopathological Features of Papillary Renal Cell Carcinoma With Venous Tumor Thrombus: Case Series from a Large Chinese Center.

Background: Few studies have reported the influence of the histological classification of type-2 papillary renal cell carcinoma (PRCC), which may differ from that of clear cell renal carcinoma (ccRCC), on the prognosis of renal cell carcinoma with tumor thrombus. We investigated the clinicopathological features and prognosis of type-2 PRCC associated with venous tumor thrombi (PRCC-TT). Methods: We retrospectively analyzed 163 patients with renal cell carcinoma with venous tumor thrombus (RCC-TT) admitted to Peking University Third Hospital between June 2016 and June 2020. Twenty-five patients had type-2 PRCC-TT and 138 had ccRCC combined with tumor thrombus; there were 125 males and 38 females. All the included patients underwent radical nephrectomy and thrombectomy under either complete laparoscopic surgery or open surgery. Univariate and multivariate Cox regression analysis were performed to evaluate the prognostic significance of each variable on cancer-specific survival (CSS). Cancer-specific survival was calculated from the date of surgery to death or the last follow-up using the Kaplan-Meier method. Results: The blood vessels of type-2 PRCC-TT presented on CT images were not as abundant as those of ccRCC-TT. Slight enhancement was observed in the corticomedullary phase. While wash-out symptoms were observed, contrast agent extinction was not obvious in the nephrographic and excretory phases. We compared the macroscopic and microscopic appearances of the 2 cohorts. Compared to the ccRCC-TT cohort, lymph node invasion was more prevalent in the PRCC-TT cohort (88.0% vs. 60.9%, P = .009). Multivariate analysis revealed that sarcomatoid differentiation, distant metastasis, and pathological type were the independent predictors of poor CSS. The Kaplan-Meier analysis showed that the CSS of type-2 PRCC-TT and ccRCC-TT were 23.5 and 38.4 months, respectively, with statistical significance (P = .002). Conclusion: Type-2 PRCC-TT varies with common ccRCC-TT in imaging manifestation and pathological characteristics. The prognosis of type-2 PRCC-TT patients was worse than that of ccRCC-TT patients.

Mutational Analysis of PBRM1 and Significance of PBRM1 Mutation in Anti-PD-1 Immunotherapy of Clear Cell Renal Cell Carcinoma.

Renal cell carcinoma is a common solid tumor. PBRM1 is one of the most mutation-prone genes in clear cell renal cell carcinoma (ccRCC) with the occurrence of mutation in 40% of ccRCC patients. Mutations in PBRM1 have been correlated with the efficacy of immunotherapy. However, the mutation types of PBRM1 are not well characterized. The effects of PBRM1 expression levels in the tumor microenvironment are not well studied. In addition, the mechanism and effect of anti-PD-1 immunotherapy in ccRCC tumor microenvironments are not well clarified. In this study, using bioinformatics methods we analyzed the alternation frequency and expression levels of PBRM1 in various tumors. Next, we experimentally validated their expression levels in ccRCC tissues from human and mouse models. We attempted to clarify the mechanisms of anti-PD-1 immunotherapy in ccRCC with various PBRM1 expression levels. Our results showed that deficiency of PBRM1 protein is correlated with CD4 T cell reduction in human and mouse ccRCC tissues. We also showed that anti-PD-1 Immunotherapy can increase the infiltration of T cells in both PBRM1 high and PBRM1 low tumors but to different degrees. Our study indicates that the reduction of CD4 cells in tumor tissues with low expression of PBRM1 may explain the compromised efficacy of anti-PD-1 immunotherapy in patients with PBRM1 mutated ccRCC. Our study sheds light on the potential of PBRM1 as a therapeutic target in ccRCC.

Predictors and survival of primary clear cell carcinoma of liver: a population-based study of an uncommon primary liver tumor.

BACKGROUND: The clinicopathological features and prognostic factors of primary clear cell carcinoma of the liver (PCCCL) remain unknown for the rarity. We aimed to determine the clinical and therapeutic characteristics of PCCCL and the effects of these factors on the prognosis. METHODS: Patients were selected from the Surveillance, Epidemiology, and End Results (SEER) database. Data were analyzed with the Kaplan-Meier, Cox proportional hazards regression analyses and the multivariable competing risk model. RESULTS: We included 223 PCCCL patients and the majority of them had an age under 75 years (82.5%). Most patients were white people (63.2%). The patients diagnosed at localized stage (63.7%), T1 (49.8%), N0 (96.0%), M0 (87.4%) and American Joint Committee on Cancer (AJCC) I (44.4%) made up the majority of the population. More PCCCL tumors had a size beneath 4 cm (74.9%) and no vascular invasion (63.2%). The 3-, 5-, and 10-year overall survival (OS) probabilities and disease-specific survival (DSS) rates were 35.8%, 24.3%, 14.4%, and 41.6%, 29.4%, 22.2%, respectively. The patients with tumor ≥1 cm [OS, hazard ratio (HR) =1.822; DSS, HR =1.959] had a higher risk of death than those patients with tumor <1 cm. Among surgical means, hepatectomy (OS, HR =0.070; DSS, HR =0.050) and total hepatectomy plus transplant (OS, HR =0.074; DSS, HR =0.065) were more beneficial to PCCCL. CONCLUSIONS: PCCCL patients were inclined to be young, white people-prevalent, localized and early. PCCCL tend to had a slow growth and be weakly aggressive. However, comparing with previous reports, we found that PCCCL had a relatively poor outcome. Tumor size and surgery were the independent prognostic factors for OS and DSS.

Advances in Radiobiology of Stereotactic Ablative Radiotherapy.

Radiotherapy (RT) has been developed with remarkable technological advances in recent years. The accuracy of RT is dramatically improved and accordingly high dose radiation of the tumors could be precisely projected. Stereotactic radiosurgery (SRS) and stereotactic body radiotherapy (SBRT), also known as stereotactic ablative radiotherapy (SABR), are rapidly becoming the accepted practice in treating solid small sized tumors. Compared with the conventional fractionation external beam radiotherapy (EBRT), SABR with very high dose per fraction and hypo-fractionated irradiation yields convincing and satisfied therapeutic effects with low toxicity, since tumor cells could be directly ablated like radiofrequency ablation (RFA). The impressive clinical efficacy of SABR is greater than expected by the linear quadratic model and the conventional radiobiological principles, i.e., 4 Rs of radiobiology (reoxygenation, repair, redistribution, and repopulation), which may no longer be suitable for the explanation of SABR's ablation effects. Based on 4 Rs of radiobiology, 5 Rs of radiobiology emphasizes the intrinsic radiosensitivity of tumor cells, which may correlate with the responsiveness of SABR. Meanwhile, SABR induced the radiobiological alteration including vascular endothelial injury and the immune activation, which has been indicated by literature reported to play a crucial role in tumor control. However, a comprehensive review involving these advances in SABR is lacking. In this review, advances in radiobiology of SABR including the role of the 4 Rs of radiobiology and potential radiobiological factors for SABR will be comprehensively reviewed and discussed.

PEX5, a novel target of microRNA-31-5p, increases radioresistance in hepatocellular carcinoma by activating Wnt/ß-catenin signaling and homologous recombination.

Rationale: Hepatocellular carcinoma (HCC) is the second leading cause of cancer-related death worldwide, with high recurrence and metastasis rates. Although radiation is an effective treatment for tumors, it is often limited by intrinsic radioresistance in HCC. The contributions of dysregulated microRNAs, including miR-31-5p, to HCC progression have been recently reported. However, the role of miR-31-5p in the radiation response of HCC is unknown. In this study, we aimed to investigate the impact of miR-31-5p on HCC radiosensitivity. Methods: miR-31-5p expression in HCC tissues, paired adjacent tissues, and HCC cell lines was measured using quantitative real-time polymerase chain reaction and in situ hybridization. Bioinformatic analyses, gain- and loss-of-function experiments, and luciferase reporter assays were performed to validate peroxisomal biogenesis factor 5 (PEX5) as a direct target of miR-31-5p. The biofunctions of PEX5 and miR-31-5p in HCC were determined by Transwell, wound-healing, and Cell Counting Kit-8 (CCK8) assays. A colony formation assay was used to evaluate the radiosensitivity of HCC cells. The interaction among PEX5, ß-catenin, Rac1, and JNK-2 was confirmed by coimmunoprecipitation. A xenograft tumor model was established to validate the effects of miR-31-5p and PEX5 on HCC progression and radiosensitivity in vivo.Results: Low expression of miR-31-5p in HCC specimens, as observed in this study, predicted a poor clinical outcome. However, the expression pattern of PEX5, as a direct target of miR-31-5p, was opposite that of miR-31-5p, and high PEX5 expression indicated poor prognosis in HCC patients. Ectopic expression of PEX5 increased the proliferation, migration, and invasion abilities and enhanced the radioresistance of HCC cells in vitro and in vivo; however, these phenotypes were inhibited by miR-31-5p. Mechanistically, PEX5 stabilized cytoplasmic ß-catenin and facilitated ß-catenin nuclear translocation to activate Wnt/ß-catenin signaling. Moreover, upon radiation exposure, PEX5 reduced excessive reactive oxygen species (ROS) accumulation and activated the homologous recombination (HR) pathway, which protected HCC cells from radiation-induced damage. Conclusions: Our findings demonstrated a novel role for PEX5 as a miR-31-5p target and a mediator of the Wnt/ß-catenin signaling and HR pathways, providing new insights into studying HCC radiation responses and implicating PEX5 and miR-31-5p as potential therapeutic targets in HCC.

Analysis of long-term outcome of image-guided volumetric modulated arc therapy (VMAT) for primary malignant tumor of the cervical spine.

OBJECTIVE: Retrospective analysis of the long-term clinical outcome and acute toxicity of the primary malignant tumor of cervical spine receiving CBCT image-guided VMAT. METHODS: Thirty patients with primary malignant tumor of the cervical spine included in our center, from December 2013 to January 2016, 28 patients were retrospectively studied. The prescription dosage 95% PTV volume dose was 44 Gy, 2.0 Gy/fraction, and a total of 22 times. The median PGTV synchronized volume dose was 60 Gy (45-62.1 Gy), median 2.5 Gy (2-2.7 Gy)/fraction. In volumetric modulated, two arc volumetric modulated arc therapy (VMAT) was used, with spinal cord dosage DMAX< 45 Gy. Early response rate and acute toxicities were analyzed. RESULT: The follow-up duration was 6-76 months (median 53 months). At the end of follow-up of June 1, 2019, 78.6% (22/28) patients were still alive. 3 and 5-y local control rates were 67.3% and 56.5% while 3 and 5-y OS were both 78.6% in the whole group of patients, respectively. Fourteen patients with chordoma 5-y local control rates and OS were 57.1% and 85.7%, respectively. Nine patients with giant-cell tumor of bone had a 5-y local control rate and OS were 77.8% and 85.7%, respectively. The response rate for moderate pain or above was 80% (8/10). Eleven patients (39.3%) suffered from grade 1 acute skin toxicity. Twenty-four patients (85.7%) had grade 1/2 mucositis. No radiation-induced spinal cord injury was found. CONCLUSION: The image-guided VMAT for primary malignant tumor of the cervical spine provided a satisfactory long-term local control rate.

Th1 Biased Progressive Autoimmunity in Aged Aire-Deficient Mice Accelerated Thymic Epithelial Cell Senescence.

Although autoimmune diseases, such as rheumatoid arthritis and systemic lupus erythematosus, are frequently associated with premature aging of the thymus, a direct link is missing between autoimmunity and thymic atrophy. Here we monitored the progression of thymic involution in Aire-deficient mice, in which defective negative selection causes spontaneous and progressive development of autoimmunity. In young and middle-aged mice, Aire deficiency appeared to be protective as supported by the reduced ß-gal+ epithelial cells and the enhanced thymic output. However, once the autoimmune phenotype was fully developed in aged Aire-deficient mice, their thymuses underwent accelerated involution. In comparison to the age-matched wildtype littermates, old Aire-deficient mice showed lower numbers of total thymocytes and recent thymic emigrants but more ß-gal+ thymic epithelial cells. This phenomenon may partly be attributable to the increased number of activated Th1 cells homing to the thymus. This speculation was further supported by the enhanced thymic aging following repeated challenges with complete Freund's adjuvant immunization. Taken together, the present study highlights a unique mechanism by which autoimmunity facilitates the senescence of thymic epithelial cells through returning Th1 cells.

CCR2 Signal Facilitates Thymic Egress by Priming Thymocyte Responses to Sphingosine-1-Phosphate.

The signal mediated by sphingosine-1-phosphate receptor 1 (S1P1) is essential but seemingly insufficient for thymic export of newly generated T cells. Here, we reported the identification of CCR2 as an additional regulator of this process. CCR2 showed a markedly increased expression in the most mature subset of single-positive (SP) thymocytes. Its deficiency led to a reduction of recent thymic emigrants in the periphery and a simultaneous accumulation of mature SP cells in the thymus. The CCR2 signaling promoted thymic emigration primarily through modulating the chemotactic responses to S1P1 engagement. On the one hand, the chemokinesis induced by CCR2 activation endowed thymocytes with enhanced capacity to respond to S1P-induced migration. On the other hand, CCR2 signaling through Stat3 augmented forkhead box O1 activity, leading to increased expression of S1P1. Taken together, the present study highlights a unique and novel function of CCR2 signaling in the regulation of thymic egress.

Critical role of SP thymocyte motility in regulation of thymic output in neonatal Aire-/- mice.

Autoimmune regulator (Aire) is essential in the perinatal period to prevent the multiorgan autoimmunity. Here we show that Aire-regulated single positive thymocyte trafficking in neonatal period is critical for thymic egress. Reduced thymic emigration was found in Aire-/- mice during neonatal period, leading to enhanced homeostatic expansion of peripheral T cells as early as 2 weeks of age. In neonatal Aire-/- mice, thymic expression of CCR7 ligands were dramatically reduced, resulting in decreased thymocyte motility and thymocyte emigration. This reduction of thymic egress in Aire-/- mice was alleviated beyond 3 weeks of age by an early upregulation of S1P1 signaling. As the numbers and quality of thymic emigrants are essential for the establishment and maintenance of peripheral tolerance, the reduced thymic emigration during neonatal period may deteriorate autoimmunity caused by the emigration of autoreactive T cells.

Trx1/TrxR1 system regulates post-selected DP thymocytes survival by modulating ASK1-JNK/p38 MAPK activities.

A key process in the development of T lymphocyte in the thymus is T-cell receptor (TCR) selection. It is controlled by complex signaling pathways that contain redox-sensitive molecules. However, the redox status early after TCR selection and how redox regulators promote the survival of post-selected DP thymocytes has not been directly addressed. The present study demonstrated that the transition from pre- to post-selected double-positive (DP) stages was accompanied with an increase of reactive oxygen species (ROS) and a transient surge in the expression of a variety of redox regulators. Among them, the thioredoxin (Trx)1/thioredoxin reductase (TrxR)1 system was found to be critically involved in the regulation of cell survival of DP thymocytes, especially that of post-selected CD69(+) subset, as its inhibition caused a specific reduction of these cells both in vitro and in vivo, most likely owing to increased apoptosis. Suppression of the glutathione-dependent redox system, on the other hand, showed no obvious impact. Biochemically, treatment of DP thymcoytes with TrxR1 inhibitor alone or in conjunction with anti-CD3 resulted in enhanced phosphorylation of redox-sensitive ASK-1, JNK and p38 MAPK, and upregulated expression of Bim. Taken together, the data presented here suggest that the timely upregulation of Trx1/TrxR1 and the active control of intracellular redox status is critical for the survival of thymocytes during and short after positive selection.