Mechanistic study of the transmission pattern of the SARS-CoV-2 omicron variant.

The omicron variant of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) characterized by 30 mutations in its spike protein, has rapidly spread worldwide since November 2021, significantly exacerbating the ongoing COVID-19 pandemic. In order to investigate the relationship between these mutations and the variant's high transmissibility, we conducted a systematic analysis of the mutational effect on spike-angiotensin-converting enzyme-2 (ACE2) interactions and explored the structural/energy correlation of key mutations, utilizing a reliable coarse-grained model. Our study extended beyond the receptor-binding domain (RBD) of spike trimer through comprehensive modeling of the full-length spike trimer rather than just the RBD. Our free-energy calculation revealed that the enhanced binding affinity between the spike protein and the ACE2 receptor is correlated with the increased structural stability of the isolated spike protein, thus explaining the omicron variant's heightened transmissibility. The conclusion was supported by our experimental analyses involving the expression and purification of the full-length spike trimer. Furthermore, the energy decomposition analysis established those electrostatic interactions make major contributions to this effect. We categorized the mutations into four groups and established an analytical framework that can be employed in studying future mutations. Additionally, our calculations rationalized the reduced affinity of the omicron variant towards most available therapeutic neutralizing antibodies, when compared with the wild type. By providing concrete experimental data and offering a solid explanation, this study contributes to a better understanding of the relationship between theories and observations and lays the foundation for future investigations.

SERPINB1 promotes Senecavirus A replication by degrading IKBKE and regulating the IFN pathway via autophagy.

IMPORTANCE: Senecavirus A (SVA) is an emerging picornavirus associated with vesicular disease, which wide spreads around the world. It has evolved multiple strategies to evade host immune surveillance. The mechanism and pathogenesis of the virus infection remain unclear. In this study, we show that SERPINB1, a member of the SERPINB family, promotes SVA replication, and regulates both innate immunity and the autophagy pathway. SERPINB1 catalyzes K48-linked polyubiquitination of IκB kinase epsilon (IKBKE) and degrades IKBKE through the proteasome pathway. Inhibition of IKBKE expression by SERPINB1 induces autophagy to decrease type I interferon signaling, and ultimately promotes SVA proliferation. These results provide importantly the theoretical basis of SVA replication and pathogenesis. SERPINB1 could be a potential therapeutic target for the control of viral infection.

Is Prophylactic Radiotherapy to the Lymphatic Drainage Area Necessary for Patients With Stage III Ovarian Cancer After Chemotherapy Following Surgery?

BACKGROUND: For patients with stage III epithelial ovarian cancer, there are limited studies on the effects of postoperative adjuvant radiotherapy (RT). Here we assessed the therapeutic efficacy and toxicity of postoperative radiotherapy to the abdominal and pelvic lymphatic drainage area for stage III epithelial ovarian cancer patients, who had all received surgery and chemotherapy (CT). METHODS: We retrospectively collected patients with stage III epithelial ovarian cancer after cytoreductive surgery (CRS) and full-course adjuvant CT. The chemoradiotherapy (CRT) group patients were treated with intensity modulated radiotherapy (IMRT) to the abdominal and pelvic lymphatic drainage area in our hospital between 2010 and 2020. A propensity score matching analysis was conducted to compare the results between the CRT and CT groups. Kaplan-Meier analysis estimated overall survival (OS), disease-free survival (DFS), and local control (LC) rates. The log-rank test determined the significance of prognostic factors. RESULTS: A total of 132 patients with median follow-up of 73.9 months (9.1-137.7 months) were included (44 and 88 for the CRT and RT groups, retrospectively). The baseline characteristics of age, histology, level of CA12-5, surgical staging, residual tumour, courses of adjuvant CT, and courses to reduce CA12-5 to normal were all balanced. The median DFS time, 5-year OS, and local recurrence free survival (LRFS) were 100.0 months vs 25.9 months (P = .020), 69.2% vs 49.9% (P = .002), and 85.9% vs 50.5% (P = .020), respectively. The CRT group mainly presented with acute haematological toxicities, with no statistically significant difference compared with grade III intestinal adverse effects (3/44 vs 6/88, P = .480). CONCLUSION: This report demonstrates that long-term DFS could be achieved in stage III epithelial ovarian cancer patients treated with IMRT preventive radiation to the abdominal and pelvic lymphatic area. Compared with the CT group, DFS and OS were significantly prolonged and adverse effects were acceptable.

Impact of Practical Online Lessons on Chinese Medical Students' Perception of Radiation Oncology.

Radiotherapy is an essential component of oncology treatment. It is imperative that clinicians and medical students have a fundamental understanding of radiotherapy. However, radiation oncology education is deficient worldwide. This study introduced an hour-long online Massive Open Online Course (MOOC) as a supplement to the basic curriculum for 8-year medical students at Peking Union Medical College and Tsinghua University in China. The students' personal opinions and comprehension of radiation oncology therapy were assessed through pre- and post-test questionnaires before and after the MOOC study. The results indicated that the percentage of students interested in radiotherapy increased, and their knowledge of radiotherapy significantly improved after the online MOOC study, suggesting that short-term MOOC study may stimulate students' interest in learning and improving their knowledge of radiation therapy. The study suggests that the combination of online and offline teaching may be a feasible way to develop radiation oncology education in the future.

Radiotherapy for postoperative vaginal recurrences of cervical squamous cell carcinoma: analysis of dosing and prognosis.

Squamous cell carcinoma (SCC) is the most common type of vaginal recurrence in cervical cancer patients, and the role of salvage radiotherapy on these patients remains unclear. This study aimed to investigate the efficacy of salvage radiotherapy for vaginal recurrence of SCC in patients who previously underwent surgery and to explore prognostic factors associated with survival. Ninety-seven patients with histologically proven SCC who were treated for vaginal recurrence at Peking Union Medical College Hospital were identified. All patients had previously undergone surgery and received salvage radiotherapy. Factors predictive of overall survival (OS), progression-free survival (PFS), and local control (LC) were investigated. The median follow-up time was 42.5 months. The estimated 5-year OS, PFS, and LC rates were 84%, 79%, and 91%. On multivariate analysis, inguinal lymph node metastasis was significantly associated with poor OS; a tumour size ≤4 cm was associated with longer PFS (p < 0.05); the recurrence pattern was an independent predictor of LC (p < 0.05). In the 45 patients with recurrences that were paravaginal or invasive of surrounding organs, biologically equivalent doses in 2 Gy fractions of ≥72.6 Gy were independently predictive of longer LC (p < 0.05). RT is an effective treatment for postoperative vaginal recurrence in patients with cervical SCC. For patients with extravaginal recurrence, a salvage dose of ≥72.6 Gy appears to be optimal.Impact statementWhat is already known on this subject? Radiotherapy plays a critical role in treating recurrent cervical cancer, but the effectiveness of RT for vaginal recurrence in patients who previously underwent surgery remains limited. Few studies have focussed on the effect of RT dose on patient survival.What do the results of this study add? This study investigated the efficacy of RT in patients with cervical squamous cell carcinoma who experienced postoperative recurrence. Lymph node metastasis, tumour size and recurrence pattern were significantly associated with survival. Moreover, an EQD2 ≥ 72.6 Gy was independently predictive of longer LC.What are the implications of these findings for clinical practice and/or further research? RT is an effective treatment for postoperative vaginal recurrence in patients with cervical squamous cell carcinoma. For patients with extravaginal recurrence, a salvage dose of ≥72.6 Gy appears to be optimal.

E2 ubiquitin-conjugating enzyme UBE2L6 promotes Senecavirus A proliferation by stabilizing the viral RNA polymerase.

Senecavirus A (SVA), discovered in 2002, is an emerging pathogen of swine that has since been reported in numerous pork producing countries. To date, the mechanism of SVA replication remains poorly understood. In this study, utilizing iTRAQ analysis we found that UBE2L6, an E2 ubiquitin-conjugating enzyme, is up-regulated in SVA-infected BHK-21 cells, and that its overexpression promotes SVA replication. We determined that UBE2L6 interacts with, and ubiquitinates the RNA-dependent RNA polymerase of SVA, (the 3D protein) and this ubiquitination serves to inhibit the degradation of 3D. UBE2L6-mediated ubiquitination of 3D requires a cystine at residue 86 in UBE2L6, and lysines at residues 169 and 321 in 3D. Virus with mutations in 3D (rK169R and rK321R) exhibited significantly decreased replication compared to wild type SVA and the repaired viruses, rK169R(R) and rK321R(R). These data indicate that UBE2L6, the enzyme, targets the 3D polymerase, the substrate, during SVA infection to facilitate replication.

Crosstalk of the Caspase Family and Mammalian Target of Rapamycin Signaling.

Cell can integrate the caspase family and mammalian target of rapamycin (mTOR) signaling in response to cellular stress triggered by environment. It is necessary here to elucidate the direct response and interaction mechanism between the two signaling pathways in regulating cell survival and determining cell fate under cellular stress. Members of the caspase family are crucial regulators of inflammation, endoplasmic reticulum stress response and apoptosis. mTOR signaling is known to mediate cell growth, nutrition and metabolism. For instance, over-nutrition can cause the hyperactivation of mTOR signaling, which is associated with diabetes. Nutrition deprivation can inhibit mTOR signaling via SH3 domain-binding protein 4. It is striking that Ras GTPase-activating protein 1 is found to mediate cell survival in a caspase-dependent manner against increasing cellular stress, which describes a new model of apoptosis. The components of mTOR signaling-raptor can be cleaved by caspases to control cell growth. In addition, mTOR is identified to coordinate the defense process of the immune system by suppressing the vitality of caspase-1 or regulating other interferon regulatory factors. The present review discusses the roles of the caspase family or mTOR pathway against cellular stress and generalizes their interplay mechanism in cell fate determination.

Transforming growth factor ß signaling pathway: A promising therapeutic target for cancer.

Transforming growth factor ß (TGF-ß) is part of the transforming growth factor ß superfamily which is involved in many physiological processes and closely related to the carcinogenesis. Here, we discuss the TGF-ß structure, function, and its canonical Smads signaling pathway. Importantly, TGF-ß has been proved that it plays both tumor suppressor as well as an activator role in tumor progression. In an early stage, TGF-ß inhibits cell proliferation and is involved in cell apoptosis. In an advanced tumor, TGF-ß signaling pathway induces tumor invasion and metastasis through promoting angiogenesis, epithelial-mesenchymal transition, and immune escape. Furthermore, we are centered on updated research results into the inhibitors as drugs which have been studied in preclinical or clinical trials in tumor carcinogenesis to prevent the TGF-ß synthesis and block its signaling pathways such as antibodies, antisense molecules, and small-molecule tyrosine kinase inhibitors. Thus, it is highlighting the crucial role of TGF-ß in tumor therapy and may provide opportunities for the new antitumor strategies in patients with cancer.

microRNA-16-5p enhances radiosensitivity through modulating Cyclin D1/E1-pRb-E2F1 pathway in prostate cancer cells.

Prostate cancer (CaP) is the second most common cancer in men worldwide in 2012, and radiation therapy is one of the most common definitive treatment options for localized CaP. However, radioresistance is a major challenge for the current radiotherapy, accumulating evidences suggest microRNAs (miRNAs), as an important regulator in cellular ionizing radiation (IR) responses, are closely correlated with radiosensitivity in many cancers. Here, we identified microRNA-16-5p(miR-16-5p) is significantly upregulated in CaP LNCaP cells following IR and can enhance radiosensitivity through modulating Cyclin D1/E1-pRb-E2F1 pathway. To identify the expression profile of miRNAs in CaP cells exposed to IR, we performed human miRNA probe hybridization chip analysis and miR-16-5p was found to be significantly overexpressed in all treatment groups that irradiated with different doses of X-rays and heavy ions (12 C6+ ). Furthermore, overexpression of miR-16-5p suppressed cell proliferation, reduced cell viability, and induced cell cycle arrest at G0/G1 phase, resulting in enhanced radiosensitivity in LNCaP cells. Additionally, miR-16-5p specifically targeted the Cyclin D1/E1-3'-UTR in LNCaP cells and affected the expression of Cyclin D1/E1 in both mRNA and protein levels. Taken together, miR-16-5p enhanced radiosensitivity of CaP cells, the mechanism may be through modulating Cyclin D1/Cyclin E1/pRb/E2F1 pathway to cause cell cycle arrest at G0/G1 phase. These findings provided new insight into the correlation between miR-16-5p, cell cycle arrest, and radiosensitivity in CaP, revealed a previously unrecognized function of miR-16-5p-Cyclin D1/E1-pRb-E2F1 regulation in response to IR and may offer an alternative therapy to improve the efficiency of conventional radiotherapy.

Dynamic recognition and repair of DNA complex damage.

Irradiation (IR) can be used to treat cancer by inducing complex and irreparable DNA damage in the cancer cells, which may lead to their apoptotic death. However, little is known about the molecular mechanism of this DNA damage. Here, the non-small-cell lung cancer cell line A549 was treated with either X-ray or carbon ion combined with bleomycin (BLM). The cell survival rate, frequency of double-strand breaks (DSBs), dynamic changes in γH2AX, and p53 binding protein 1 (53BP1), and protein expression of Ku70, Rad51, and XRCC1 were determined by the clone formation assay, agarose gel electrophoresis, immunofluorescence, and western blot analysis. The results showed that the most obvious complex DSBs occurred in the carbon IR + BLM group. The number of γH2AX and 53BP1 foci in the 0.5 hr X-ray IR + BLM group was the highest (p < 0.001) among all the groups. γH2AX foci were detected in the nucleus at 0.5, 1, 2, and 4 hr, but were distributed throughout the cell at 6 hr after IR in the carbon ion IR + BLM group. The expression of Ku70 increased and XRCC1 decreased at 2 and 6 hr after IR. Our data indicate that a DNA damage frequency of 13.4/Mbp is caused by clustered DNA damage and further show a correlation between γH2AX, 53BP1, and XRCC1 levels and the extent of DNA damage. The results of this study provide insights into DNA damage recognition and a rationale for the clinical use of radiotherapy.

Mitochondrial proteomics reveals the mechanism of spermatogenic cells apoptosis induced by carbon ion radiation in zebrafish.

The mitochondrial proteins involved in spermatogenic cells apoptosis in zebrafish after carbon ion radiation (CIR) were screened. The relative biological effectiveness (RBE) of CIR in zebrafish testes was investigated. Apoptosis of testicular cells was measured within 24 hr following 1 and 4 Gy CIR. Immunoblotting was used to assess the levels of mitochondrial apoptotic proteins in testes, and proliferative and apoptotic spermatogenic cells were detected by immunofluorescence after CIR. Label-free quantitative (LFQ) and parallel reaction monitoring-based target proteomics (PRM) were combined to screen and validate differential mitochondrial proteins in testes between 4 Gy and control groups at 24 hr after CIR. The RBE of CIR in zebrafish testes was 1.48 ± 0.04, and induction of apoptosis by CIR was higher than that of X-rays in testicular cells. Mitochondrial apoptotic pathways play a crucial role in spermatogenic cells apoptosis after CIR, with 60 differential mitochondrial proteins identified. Among 20 target proteins, 12 were significantly upregulated, 2 were significantly downregulated in the 4 Gy CIR group. The results of PRM were consistent with label-free analysis. This is the first study to screen the differential mitochondrial proteins and provide useful information to understand the underlying mechanisms of spermatogenic cell apoptosis in zebrafish following CIR.

Posttreatment squamous cell carcinoma antigen predicts treatment failure in patients with cervical squamous cell carcinoma treated with concurrent chemoradiotherapy.

OBJECTIVE: To analyze the association between posttreatment squamous cell carcinoma antigen (SCC Ag) and treatment failure in patients with cervical SCC treated with concurrent chemoradiotherapy (CCRT). METHODS: We reviewed patients with cervical SCC who were treated with definitive radiotherapy or CCRT between June 2012 and May 2015 at our institute. A receiver operating characteristic (ROC) curve was used to analyze the cutoff value of posttreatment SCC Ag in predicting treatment failure. Log-rank tests and Cox proportional hazards models were used to identify whether posttreatment SCC Ag was significant in predicting disease-free survival (DFS). RESULTS: A total of 559 patients were included in this study. With the ROC curve, the optimal cutoff posttreatment SCC Ag level was 1.8 ng/mL (sensitivity 27.1%, specificity 96.6%). A posttreatment SCC Ag level ≥ 1.8 ng/mL was observed in 47 patients. The multivariate analysis showed that posttreatment SCC Ag (hazard ratio 5.10; 95% confidence interval, 3.31-7.88; p < 0.001) was an independent prognostic factor of DFS. The 3-year overall survival (OS), DFS, local control, and distant control rates of patients with posttreatment SCC Ag < 1.8 ng/mL and ≥1.8 ng/mL were 90.7% and 46.4% (p < 0.001), 84.8% and 31.9% (p < 0.001), 81.4% and 69.5% (p < 0.001), and 90.4% and 54.1% (p < 0.001), respectively. CONCLUSION: Patients with posttreatment SCC Ag ≥ 1.8 ng/mL suffer due to a high rate of treatment failure and poor survival.

E2F is involved in radioresistance of carbon ion induced apoptosis via Bax/caspase 3 signal pathway in human hepatoma cell.

Deletion of p53, most common genetic alteration, is observed in human tumors and reported to lead to improve in cell radioresistance. Heavy-ion irradiation (IR) could induce p53-/- cancer cells apoptosis. However, little is known regarding the molecular mechanism in this type of cell apoptosis. The present studies have focused on mechanisms state of signaling pathways as an activator of the cell fate decisions induced by heavy ion IR without p53. Carbon ion IR could induce up-regulation of E2F1 expression in cancer cells. This phenomenon was not observed in X-ray IR group. Up-regulation of E2F1 could cause a higher reduction in clonogenic survival, low level of cellular activity, G2 /M phase arrest, promotion of apoptosis rate, up-regulation of phosphor-Rb, Bax, and cleaved-caspase 3 proteins expressions without p53. Changes of E2F1 expressions could partly alter radioresistance in cancer cells. The results were suggested that heavy ion IR could induce p53-/- cancer cells apoptosis via E2F1 signal pathway. Our study provides a scientific rationale for the clinical use of heavy ion as radiotherapy in patients with p53-deficient tumors, which are often resistant to radiotherapy.

Outcome and toxicity of radical radiotherapy or concurrent Chemoradiotherapy for elderly cervical cancer women.

BACKGROUND: Concurrent chemoradiotherapy (CCRT) is the standard treatment for local advanced cervical cancer. However, for elderly patients, studies are limited and the outcomes are controversial. We retrospectively analyzed the efficacy and tolerance of radical radiotherapy (RT) or CCRT in elderly cervical cancer patients and performed comparisons between them. METHODS: We retrospectively analyzed the elderly cervical cancer patients (≥70 years old) treated with radical RT or CCRT between January 2006 and December 2014. For external beam radiotherapy, 50Gy in 25 fractions or 50.4Gy in 28 fractions were delivered via 3-dimensional conformal radiation therapy or intensity modulated radiation therapy. High-dose-rate intracavitary brachytherapy was performed with a dose of 30-36Gy in 5-7 fractions to point A. Concurrent chemotherapy regimens included weekly cisplatin and paclitaxel. RESULTS: Seventy-three patients were eligible for this study. Twenty-one(28.8%) and 52(71.2%) patients suffered with FIGO stage IB-IIA and IIB-IVA disease, respectively. Twenty-four (32.9%) patients received CCRT. The median duration of follow-up was 32.4 months (4.8-118.8 months). The 3-year overall survival (OS), cancer-specific survival (CSS) and disease-free survival (DFS) were 64.9%, 67.8% and 66.5%, respectively. By multivariate analysis, CCRT was a significant predictive factor of OS(p = 0.023, 95% confidence interval [CI]: 1.172-8.860), CSS(p = 0.031, 95% CI: 1.131-13.908)and DFS(p = 0.045, 95% CI: 1.023 ~ 6.430). The 3-year OS of patients received RT and CCRT were 54.3% and 83.1%, CSS were 56.8% and 87.1%, DFS were 57.6% and 83.3%. There was no treatment related death. Grade 3-4 acute hematological, gastrointestinal and urinary toxicity incidences were 31.5%, 19.1% and 12.3%, respectively. For grade 3-4 chronic gastrointestinal and genitourinary toxicities, the incidences were 4.1% and 2.7%, respectively. Compared with RT, CCRT was related with high grade 3-4 hematological toxicity (16.3% and 62.5% respectively, p < 0.001), respectively. However, acute nonhematological toxicity and chronic toxicity were not significantly different. CONCLUSION: Elderly cervical cancer patients could tolerate radical RT and CCRT very well and get a favored survival. Compared with RT, CCRT could improve the survival of elder cervical cancer patients with similar nonhematological toxicity. CCRT should be considered in elderly cervical cancer patients.

Pelvic target volume inter-fractional motion during radiotherapy for cervical cancer with daily iterative cone beam computed tomography.

BACKGROUND: Tumor regression and organ movements indicate that a large margin is used to ensure target volume coverage during radiotherapy. This study aimed to quantify inter-fractional movements of the uterus and cervix in patients with cervical cancer undergoing radiotherapy and to evaluate the clinical target volume (CTV) coverage. METHODS: This study analyzed 303 iterative cone beam computed tomography (iCBCT) scans from 15 cervical cancer patients undergoing external beam radiotherapy. CTVs of the uterus (CTV-U) and cervix (CTV-C) contours were delineated based on each iCBCT image. CTV-U encompassed the uterus, while CTV-C included the cervix, vagina, and adjacent parametrial regions. Compared with the planning CTV, the movement of CTV-U and CTV-C in the anterior-posterior, superior-inferior, and lateral directions between iCBCT scans was measured. Uniform expansions were applied to the planning CTV to assess target coverage. RESULTS: The motion (mean ± standard deviation) in the CTV-U position was 8.3 ± 4.1 mm in the left, 9.8 ± 4.4 mm in the right, 12.6 ± 4.0 mm in the anterior, 8.8 ± 5.1 mm in the posterior, 5.7 ± 5.4 mm in the superior, and 3.0 ± 3.2 mm in the inferior direction. The mean CTV-C displacement was 7.3 ± 3.2 mm in the left, 8.6 ± 3.8 mm in the right, 9.0 ± 6.1 mm in the anterior, 8.4 ± 3.6 mm in the posterior, 5.0 ± 5.0 mm in the superior, and 3.0 ± 2.5 mm in the inferior direction. Compared with the other tumor (T) stages, CTV-U and CTV-C motion in stage T1 was larger. A uniform CTV planning treatment volume margin of 15 mm failed to encompass the CTV-U and CTV-C in 11.1% and 2.2% of all fractions, respectively. The mean volume change of CTV-U and CTV-C were 150% and 51%, respectively, compared with the planning CTV. CONCLUSIONS: Movements of the uterine corpus are larger than those of the cervix. The likelihood of missing the CTV is significantly increased due to inter-fractional motion when utilizing traditional planning margins. Early T stage may require larger margins. Personal radiotherapy margining is needed to improve treatment accuracy.

CT-guided hydrogel injection for brachytherapy in cervical cancer: A case report.

Rectal toxicity is a significant concern in cervical cancer radiotherapy. Despite advancements in image-guided brachytherapy (IGBT), rectal morbidity remains a challenge. Injectable hydrogel showed promise in creating a space between the vagina and rectum, reducing rectal radiation dose; however, the traditional ultrasound-guided injection revealed some problems, such as the inadequate separation of the upper edge of the cervix, which can be mitigated through adopting CT-guided injection. This case report presents the successful use of computed tomography (CT)-guided hydrogel injection to limit rectal doses and improve treatment outcomes. A forty-year-old female with stage IIIC1r cervical cancer received external-beam radiotherapy and concurrent chemotherapy. Due to the proximity of the tumor to the rectum, a CT-guided hydrogel injection was performed to increase the distance between the cervix and rectum. Post-injection, magnetic resonance imaging (MRI) demonstrated increased distances between the cervix and rectum. Subsequent MRI-based IGBT achieved high clinical target volume doses while limiting rectal doses. During the six-month follow-up, the patient reported only mild adverse effects. CT-guided hydrogel injection offers advantages over ultrasound-guided injection in cervical cancer radiotherapy. The technique allows for better puncture position adjustment, reduced reliance on specialized ultrasound expertise, and shorter puncture distances. This case report highlights the potential of hydrogel injection as a viable method to reduce rectal morbidity and improve treatment outcomes in a broader range of cervical cancer patients. Further studies are warranted to validate these findings and explore its applicability in larger cohorts.

Rebalancing TGF-ß/PGE2 breaks RT-induced immunosuppressive barriers by enhancing tumor-infiltrated dendritic cell homing.

A better understanding of how tumor microenvironments shape immune responses after radiotherapy (RT) is required to improve patient outcomes. This study focuses on the observation that dendritic cells (DCs) infiltrating irradiated cervical tumors are retained in transforming growth factor (TGF)-ß-abundant regions. We report that TGF-ß secretion from cervical cancer cells was increased by irradiation in a dose-dependent manner and that this significantly suppressed the expression of allostimulatory markers and Th1 cytokines in DCs. To investigate further, we blocked the TGF-ß signal in DCs and observed that RT had a dose-dependent immune-promoting effect, improving DC maturation. This suggested that proinflammatory mediators may also be induced by RT, but their effects were being counteracted by the simultaneously increased levels of TGF-ß. Prostaglandin E2 (PGE2), a proinflammatory molecule, was shown to be one such mediator. Adjusting the TGF-ß/PGE2 ratio by inhibiting TGF-ß rebooted RT-induced DC cytoskeletal organization by stimulating myosin light chain (MLC) phosphorylation. Consequently, the homing of intra-tumorally infiltrated DCs to tumor-draining lymph nodes was enhanced, leading to the induction of more robust cytotoxic T cells. Ultimately, rebalancing the TGF-ß/PGE2 ratio amplified the therapeutic effects of RT, resulting in increased intra-tumoral infiltration and activation of CD8+ T cells, and improved tumor control and overall survival rate in mice. DC depletion experiments verified that the improvement in tumor control is directly correlated with the involvement of DCs via the PGE2-MLC pathway. This study emphasizes the importance of maintaining a balanced cytokine environment during RT, particularly hypofractionated RT; and it is advisable to block TGF-ß while preserving PGE2 in the tumor microenvironment in order to better stimulate DC homing and DC -T priming.

Evaluation of PTV margins with daily iterative online adaptive radiotherapy for postoperative treatment of endometrial and cervical cancer: a prospective single-arm phase 2 study.

BACKGROUND: To determine the optimal planning target volume (PTV) margins for adequate coverage by daily iterative cone-beam computed tomography (iCBCT)-guided online adaptive radiotherapy (oART) in postoperative treatment of endometrial and cervical cancer and the benefit of reducing PTV margins. METHODS: Fifteen postoperative endometrial and cervical cancer patients treated with daily iCBCT-guided oART were enrolled in this prospective phase 2 study. Pre- and posttreatment iCBCT images of 125 fractions from 5 patients were obtained as a training cohort, and clinical target volumes (CTV) were contoured separately. Uniform three-dimensional expansions were applied to the PTVpre to assess the minimum margin required to encompass the CTVpost. The dosimetric advantages of the proposed online adaptive margins were compared with conventional margin plans (7-15 mm) using an oART emulator in another cohort of 125 iCBCT scans. A CTV-to-PTV expansion was verified on a validation cohort of 253 fractions from 10 patients, and further margin reduction and acute toxicity were studied. RESULTS: The average time from pretreatment iCBCT to posttreatment iCBCT was 22 min. A uniform PTV margin of 5 mm could encompass nodal CTVpost in 100% of the fractions (175/175) and vaginal CTVpost in 98% of the fractions (172/175). The margin of 5 mm was verified in our validation cohort, and the nodal PTV margin could be further reduced to 4 mm if ≥ 95% CTV coverage was predicted to be achieved. The adapted plan with a 5 mm margin significantly improved pelvic organ-at-risk dosimetry compared with the conventional margin plan. Grade 3 toxicities were observed in only one patient with leukopenia, and no patients experienced acute urinary toxicity. CONCLUSION: In the postoperative treatment of endometrial and cervical cancer, oART could reduce PTV margins to 5 mm, which significantly decrease the dose to critical organs at risk and potentially lead to a lower incidence of acute toxicity.

A survey on brachytherapy training of gynecological cancer focusing on the competence of residents in China.

BACKGROUND: The brachytherapy is an indispensable treatment for gynecological tumors, but the quality and efficiency of brachytherapy training for residents is still unclear. METHODS: An anonymous questionnaire was designed to collect information on gynecological brachytherapy (GBT) training for radiation oncology residents from 28 training bases in China. The questionnaire content was designed based on the principle of competency based medical education (CBME). The Likert scale was employed to evaluate self-reported competence and comprehension regarding GBT. A total of 132 senior residents were included in the final analysis. RESULTS: 53.79% (71/132) of senior residents had experience in performing image-guided GBT, whereas 76.52% (101/132) had observed the procedure during their standardized residency training. The proportion of senior residents who reported having the self-reported competence to independently complete the GBT was 78.03% for intracavity GBT, 75.00% for vaginal stump GBT, and 50.03% for interstitial GBT, respectively. The number of successful completion of Interstitial, intracavity and vaginal GBT was correlated with the self- confidence of trainees after standardized training. In particular, the independent completion of interstitial GBT for more than 20 cases was an independent factor for the self-reported competence of senior residents. During the training period, 50.76% and 56.82% of the residents had not participated in the specialized examinations and professional GBT courses. CONCLUSIONS: The study revealed that the self-confidence of residents to independently complete brachytherapy was relatively high, and the specialized curriculum setting and training process assessment for brachytherapy training still need to be strengthened in the future.

Daily Online Adaptive Radiation Therapy of Postoperative Endometrial and Cervical Cancer With PTV Margin Reduction to 5 mm: Dosimetric Outcomes, Acute Toxicity, and First Clinical Experience.

Purpose: This study evaluated the first clinical implementation of daily iterative cone beam computed tomography (iCBCT)-guided online adaptive radiation therapy (oART) in the postoperative treatment of endometrial and cervical cancer. Methods and Materials: Seventeen consecutive patients treated with daily iCBCT-guided oART were enrolled in this prospective study, with a reduced uniform 3-dimensional PTV margin of 5 mm. Treatment plans were designed to deliver 45 or 50.4 Gy in 1.8 Gy daily fractions to PTV. Pre- and posttreatment ultrasound and iCBCT scans were performed to record intrafractional bladder and rectal volume changes. The accuracy of contouring, oART procedure time, dosimetric outcomes, and acute toxicity were evaluated. Results: The average time from first iCBCT acquisition to completion of treatment was 22 minutes and 26 seconds. During this period, bladder volume increased by 44 cm3 using iCBCT contouring, whereas rectal volume remained stable (62.9 cm3 pretreatment vs 61.9 cm3 posttreatment). A total of 91.6% of influencers and 88.1% of CTVs required no or minor edits. The adapted plan was selected in all (434) fractions and significantly improved the dosimetry coverage for CTV and PTV, especially the vaginal PTV coverage by nearly 7% (P < .05). The adapted bladder Dmean was 104.61 cGy, and the rectum Dmean was 123.67 cGy, significantly lower than the scheduled plan of 108.24 and 128.19 cGy, respectively. The bone marrow and femur head left and right dosimetry were also improved with adaptation. Grade 2 acute gastrointestinal and genitourinary toxicities were 24% and 0, respectively. There was a grade 3 acute toxicity of decreased white blood cell count in 1 patient. Conclusions: Daily oART was associated with favorable dosimetry improvement and low acute toxicity, supporting its safety and efficacy for postoperative treatment of endometrial and cervical cancer. These results need to be validated in a larger prospective randomized controlled cohort.