Risk Factors for Distant Metastasis in Extrahepatic Bile Duct Cancer after Curative Resection (KROG 1814).

PURPOSE: Risk factors predicting distant metastasis (DM) in extrahepatic bile duct cancer (EHBDC) patients treated with curative resection were investigated. MATERIALS AND METHODS: Medical records of 1,418 EHBDC patients undergoing curative resection between Jan 2000 and Dec 2015 from 14 institutions were reviewed. After resection, 924 patients (67.6%) were surveilled without adjuvant therapy, 297 (21.7%) were treated with concurrent chemoradiotherapy (CCRT) and 148 (10.8%) with CCRT followed by chemotherapy. To exclude the treatment effect from innate confounders, patients not treated with adjuvant therapy were evaluated. RESULTS: After a median follow-up of 36.7 months (range, 2.7 to 213.2 months), the 5-year distant metastasis-free survival (DMFS) rate was 57.7%. On multivariate analysis, perihilar or diffuse tumor (hazard ratio [HR], 1.391; p=0.004), poorly differentiated histology (HR, 2.014; p < 0.001), presence of perineural invasion (HR, 1.768; p < 0.001), positive nodal metastasis (HR, 2.670; p < 0.001) and preoperative carbohydrate antigen (CA) 19-9 ≥ 37 U/mL (HR, 1.353; p < 0.001) were significantly associated with inferior DMFS. The DMFS rates significantly differed according to the number of these risk factors. For validation, patients who underwent adjuvant therapy were evaluated. In patients with ≥ 3 factors, additional chemotherapy after CCRT resulted in a superior DMFS compared with CCRT alone (5-year rate, 47.6% vs. 27.7%; p=0.001), but the benefit of additional chemotherapy was not observed in patients with 0-2 risk factors. CONCLUSION: Tumor location, histologic differentiation, perineural invasion, lymph node metastasis, and preoperative CA 19-9 level predicted DM risk in resected EHBDC. These risk factors might help identifying a subset of patients who could benefit from additional chemotherapy after resection.

Identification of dendritic cell precursor from the CD11c+ cells expressing high levels of MHC class II molecules in the culture of bone marrow with FLT3 ligand.

Dendritic cells (DCs) are readily generated from the culture of mouse bone marrow (BM) treated with either granulocyte macrophage-colony stimulating factor (GM-CSF) or FMS-like tyrosine kinase 3 ligand (FLT3L). CD11c+MHCII+ or CD11c+MHCIIhi cells are routinely isolated from those BM cultures and generally used as in vitro-generated DCs for a variety of experiments and therapies. Here, we examined CD11c+ cells in the BM culture with GM-CSF or FLT3L by staining with a monoclonal antibody 2A1 that is known to recognize mature or activated DCs. Most of the cells within the CD11c+MHCIIhi DC gate were 2A1+ in the BM culture with GM-CSF (GM-BM culture). In the BM culture with FLT3L (FL-BM culture), almost of all the CD11c+MHCIIhi cells were within the classical DC2 (cDC2) gate. The analysis of FL-BM culture revealed that a majority of cDC2-gated CD11c+MHCIIhi cells exhibited a 2A1-CD83-CD115+CX3CR1+ phenotype, and the others consisted of 2A1+CD83+CD115-CX3CR1- and 2A1-CD83-CD115-CX3CR1- cells. According to the antigen uptake and presentation, morphologies, and gene expression profiles, 2A1-CD83-CD115-CX3CR1- cells were immature cDC2s and 2A1+CD83+CD115-CX3CR1- cells were mature cDC2s. Unexpectedly, however, 2A1-CD83-CD115+CX3CR1+ cells, the most abundant cDC2-gated MHCIIhi cell subset in FL-BM culture, were non-DCs. Adoptive cell transfer experiments in the FL-BM culture confirmed that the cDC2-gated MHCIIhi non-DCs were precursors to cDC2s, i.e., MHCIIhi pre-cDC2s. MHCIIhi pre-cDC2s also expressed the higher level of DC-specific transcription factor Zbtb46 as similarly as immature cDC2s. Besides, MHCIIhi pre-cDC2s were generated only from pre-cDCs and common DC progenitor (CDP) cells but not from monocytes and common monocyte progenitor (cMoP) cells, verifying that MHCIIhi pre-cDC2s are close lineage to cDCs. All in all, our study identified and characterized a new cDC precursor, exhibiting a CD11c+MHCIIhiCD115+CX3CR1+ phenotype, in FL-BM culture.

Pancreatoduodenectomy with uncut-Roux-en-Y reconstruction in patients with previous radical gastrectomy.

Gastric cancer is very common. Many patients have undergone radical gastric cancer surgery in Korea. Recently, the number of cases with secondary cancer occurring in other organs such as periampullary cancers is increasing as survival rate of gastric cancer patients increases. There are some clinical issues in managing patients with periampullary cancer who have undergone radical gastrectomy previously. Considering that pancreatoduodectomy (PD) has two phases (i.e., resection and reconstruction), it can be very complicated and controversial to perform safe and effective reconstruction following PD in patients with a previous radical gastrectomy. In this report, we present our experiences of uncut-Roux-en-Y fashioned reconstruction in PD for patients with a previous radical gastrectomy and discuss its technical characteristics and potential advantages.

Dummy run quality assurance study in the Korean Radiation Oncology Group 19 - 09 multi-institutional prospective cohort study of breast cancer.

BACKGROUND: The Korean Radiation Oncology Group (KROG) 19 - 09 prospective cohort study aims to determine the effect of regional nodal irradiation on regional recurrence rates in ypN0 breast cancer patients. Dosimetric variations between radiotherapy (RT) plans of participating institutions may affect the clinical outcome of the study. We performed this study to assess inter-institutional dosimetric variations by dummy run. METHODS: Twelve participating institutions created RT plans for four clinical scenarios using computed tomography images of two dummy cases. Based on a reference structure set, we analyzed dose-volume histograms after collecting the RT plans. RESULTS: We found variations in dose distribution between institutions, especially in the regional nodal areas. Whole breast and regional nodal irradiation (WBI + RNI) plans had lower inter-institutional agreement and similarity for 95% isodose lines than WBI plans. Fleiss's kappa values, which were used to measure inter-institutional agreement for the 95% isodose lines, were 0.830 and 0.767 for the large and medium breast WBI plans, respectively, and 0.731 and 0.679 for the large and medium breast WBI + RNI plans, respectively. There were outliers in minimum dose delivered to 95% of the structure (D95%) of axillary level 1 among WBI plans and in D95% of the interpectoral region and axillary level 4 among WBI + RNI plans. CONCLUSION: We found inter-institutional and inter-case variations in radiation dose delivered to target volumes and organs at risk. As KROG 19 - 09 is a prospective cohort study, we accepted the dosimetric variation among the different institutions. Actual patient RT plan data should be collected to achieve reliable KROG 19 - 09 study results.

Effect of Elective Internal Mammary Node Irradiation on Disease-Free Survival in Women With Node-Positive Breast Cancer: A Randomized Phase 3 Clinical Trial.

IMPORTANCE: The benefit of internal mammary node irradiation (IMNI) for treatment outcomes in node-positive breast cancer is unknown. OBJECTIVE: To investigate whether the inclusion of IMNI in regional nodal irradiation improves disease-free survival (DFS) in women with node-positive breast cancer. DESIGN, SETTING, AND PARTICIPANTS: This multicenter, phase 3 randomized clinical trial was conducted from June 1, 2008, to February 29, 2020, at 13 hospitals in South Korea. Women with pathologically confirmed, node-positive breast cancer after breast-conservation surgery or mastectomy with axillary lymph node dissection were eligible and enrolled between November 19, 2008, and January 14, 2013. Patients with distant metastasis and those who had received neoadjuvant treatment were excluded. Data analyses were performed according to the intention-to-treat principle. INTERVENTIONS: All patients underwent regional nodal irradiation along with breast or chest wall irradiation. They were randomized 1:1 to receive radiotherapy either with IMNI or without IMNI. MAIN OUTCOMES AND MEASURES: The primary end point was the 7-year DFS. Secondary end points included the rates of overall survival, breast cancer-specific survival, and toxic effects. RESULTS: A total of 735 women (mean [SD] age, 49.0 [9.1] years) were included in the analyses, of whom 373 received regional nodal irradiation without IMNI and 362 received regional nodal irradiation with IMNI. Nearly all patients underwent taxane-based adjuvant systemic treatment. The median (IQR) follow-up was 100.4 (89.7-112.1) months. The 7-year DFS rates did not significantly differ between the groups treated without IMNI and with IMNI (81.9% vs 85.3%; hazard ratio [HR], 0.80; 95% CI, 0.57-1.14; log-rank P = .22). However, an ad hoc subgroup analysis showed significantly higher DFS rates with IMNI among patients with mediocentrally located tumors. In this subgroup, the 7-year DFS rates were 81.6% without IMNI vs 91.8% with IMNI (HR, 0.42; 95% CI, 0.22-0.82; log-rank P = .008), and the 7-year breast cancer mortality rates were 10.2% without IMNI vs 4.9% with IMNI (HR, 0.41; 95% CI, 0.17-0.99; log-rank P = .04). No differences were found between the 2 groups in the incidence of adverse effects, including cardiac toxic effects and radiation pneumonitis. CONCLUSIONS AND RELEVANCE: This randomized clinical trial found that including IMNI in regional nodal irradiation did not significantly improve the DFS in patients with node-positive breast cancer. However, patients with medially or centrally located tumors may benefit from the use of IMNI. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT04803266.

Role of adjuvant radiotherapy in extrahepatic bile duct cancer: A multicenter retrospective study (Korean Radiation Oncology Group 18-14).

PURPOSE: To evaluate the role of adjuvant radiotherapy (RT) after curative resection in patients with extrahepatic bile duct (EHBD) cancer. METHODS: Between January 2000 and December 2015, 1475 patients with EHBD cancer who underwent curative resection were accrued from 14 institutions in Korea. Among these, 959 patients did not receive any adjuvant therapy (RT(-) group), while 516 underwent postoperative RT with or without chemotherapy (RT(+) group). RESULTS: The median age was 67 years. Nodal involvement was present in 482 patients (32.7%), and resection margin was involved in 293 patients (19.9%). RT(+) group had more patients with proximal tumours, advanced tumours, nodal involvement, perineural invasion, and involved resection margin than RT(-) group (all p < 0.001). With a median follow-up of 36 months, there were 211 locoregional recurrences, 307 distant metastases and 322 combined locoregional and distant failures. On multivariate analysis incorporating age, tumour location, differentiation, pT classification, pN classification, perineural invasion and resection margin, adjuvant RT was associated with improved overall survival (hazard ratio, 0.74; 95% confidence interval, 0.63-0.86; p < 0.001). When RT(+) group was separated into RT alone, concurrent chemoradiotherapy (CCRT) and CCRT followed by chemotherapy, the greatest benefit was observed in patients treated with CCRT followed by chemotherapy (hazard ratio, 0.52; 95% confidence interval, 0.41-0.68). CONCLUSIONS: Adjuvant RT combined with chemotherapy improved survival outcomes of resected EHBD cancer patients. Considering the greatest benefit observed in patients receiving CCRT followed by chemotherapy, a randomised controlled trial comparing chemotherapy alone and CCRT followed by chemotherapy is urgently needed.

Inter-institutional Variation in Intensity-modulated Radiotherapy for Breast Cancer in Korea (KROG 19-01).

BACKGROUND/AIM: To present the variations in the target delineation and the planning results of intensity-modulated radiation therapy (IMRT) for breast cancers. PATIENTS AND METHODS: We requested the target volumes and organs at risk delineation for two cases of left breast cancers, and evaluated the IMRT plans including the supraclavicular and internal mammary node irradiation. RESULTS: Twenty-one institutions participated in this study. Differences in the planning target volume among institutions reached up to three-times for breast-conserving surgery (BCS) case and five-times for mastectomy case. Mean heart doses ranged from 3.3 to 24.1 Gy for BCS case and from 5.0 to 26.5 Gy for mastectomy case. Ipsilateral lung volumes receiving more than 20 Gy ranged from 4.7 to 57.4% for BCS case and from 16.4 to 55.5% for mastectomy case. CONCLUSION: There were large variations in the target delineation and planning results of IMRT for breast cancers among institutions. Considering the increased use of breast IMRT, more standardized protocols are needed.

Functional recovery by colon organoid transplantation in a mouse model of radiation proctitis.

Radiation proctitis is the collateral damage that occurs to healthy cells during radiation treatment of pelvic malignancies. Conservative treatment of radiation proctitis can mitigate inflammatory symptoms, but, to date, no therapeutic options are available for direct recovery of the damaged colonic epithelium. The present study assessed the ability of colon organoid-based regeneration to treat radiation proctitis. Radiation proctitis was induced in mice by irradiating their recta, followed by enema-based transplantation of mouse colon organoids. The transplanted colon organoids were found to successfully engraft onto the damaged rectal mucosa of the irradiated mice, reconstituting epithelial structure and integrity. Lgr5+ stem cells were shown to be pivotal to colon organoid mediated regeneration. Endoscopic examination showed the efficacy of localized transplantation of colon organoids with fibrin glue to irradiated sites. These findings provide useful insights into the use of colon organoid-based regenerative therapy for the treatment of radiation proctitis.

Distinct Repopulation Activity in Hu-Mice Between CB- and LPB-CD34＋ Cells by Enrichment of Transcription Factors.

BACKGROUND AND OBJECTIVES: Human CD34＋ hematopoietic stem cells can reconstitute the human hematopoietic system when transplanted into immunocompromised mice after irradiation. Human leukapheresis peripheral blood (LPB)- and cord blood (CB)-derived CD34＋ cells have a similar capacity to reconstitute myeloid lineage cells in a humanized mice (hu-mice) model. However, potent stem cells, such as CB-CD34＋ cells, efficiently reconstitute the lymphoid system in vivo compared to LPB-CD34＋ cells. Modeling the human hematolymphoid system is vital for studying immune cell crosstalk in human xenografted mice, with CB-CD34＋ cells used as an optimized cell source because they are essential in reconstituting lymphoid lineage cells. METHODS AND RESULTS: In this study, we established hu-mice that combined human characteristics with long-term survival and investigated the efficiency of the engraftment of lymphoid lineage cells derived from LPB- and CB-CD34＋ cells in the bone marrow, spleen, and LPB. We found an overall increase in the transcriptional activity of lymphoid lineage genes in CB-CD34＋ cells. Our results revealed that potent CB-CD34＋ cells displaying a general upregulation of the expression of genes involved in lymphopoiesis could contribute to the hematolymphoid system in the humanized mice model with longevity. CONCLUSIONS: Our data suggest that humanized mouse model by usage of CB-CD34＋ cells displaying high expression of TFs for lymphoid lineage cells can contribute to study the immune response against lymphocytes.

Granulocyte Macrophage-Colony Stimulating Factor Produces a Splenic Subset of Monocyte-Derived Dendritic Cells That Efficiently Polarize T Helper Type 2 Cells in Response to Blood-Borne Antigen.

Dendritic cells (DCs) are key antigen-presenting cells that prime naive T cells and initiate adaptive immunity. Although the genetic deficiency and transgenic overexpression of granulocyte macrophage-colony stimulating factor (GM-CSF) signaling were reported to influence the homeostasis of DCs, the in vivo development of DC subsets following injection of GM-CSF has not been analyzed in detail. Among the treatment of mice with different hematopoietic cytokines, only GM-CSF generates a distinct subset of XCR1-33D1- DCs which make up the majority of DCs in the spleen after three daily injections. These GM-CSF-induced DCs (GMiDCs) are distinguished from classical DCs (cDCs) in the spleen by their expression of CD115 and CD301b and by their superior ability to present blood-borne antigen and thus to stimulate CD4+ T cells. Unlike cDCs in the spleen, GMiDCs are exceptionally effective to polarize and expand T helper type 2 (Th2) cells and able to induce allergic sensitization in response to blood-borne antigen. Single-cell RNA sequencing analysis and adoptive cell transfer assay reveal the sequential differentiation of classical monocytes into pre-GMiDCs and GMiDCs. Interestingly, mixed bone marrow chimeric mice of Csf2rb+/+ and Csf2rb-/- demonstrate that the generation of GMiDCs necessitates the cis expression of GM-CSF receptor. Besides the spleen, GMiDCs are generated in the CCR7-independent resident DCs of the LNs and in some peripheral tissues with GM-CSF treatment. Also, small but significant numbers of GMiDCs are generated in the spleen and other tissues during chronic allergic inflammation. Collectively, our present study identifies a splenic subset of CD115hiCD301b+ GMiDCs that possess a strong capacity to promote Th2 polarization and allergic sensitization against blood-borne antigen.

Feasibility and early toxicity of focal or partial brachytherapy in prostate cancer patients.

PURPOSE: The aim of this study was to compare short-term oncologic outcomes and toxicity of focal or partial low-dose-rate brachytherapy (focal/partial LDR-BT) with whole gland low-dose-rate brachytherapy (whole LDR-BT) in localized prostate cancer patients. MATERIAL AND METHODS: Medical records of eligible patients who underwent focal/partial LDR-BT and whole LDR-BT between 2015 and 2017 at our institution were reviewed retrospectively. Clinical characteristics and pathologic outcomes were compared between focal/partial LDR-BT group and whole LDR-BT group. Biochemical recurrence-free survival was analyzed using Kaplan-Meier method and difference between two groups was assessed with log-rank test. Genitourinary and rectal toxicity were also evaluated between the two groups. RESULTS: Of the 60 patients analyzed, 30 focal/partial LDR-BT patients and 30 whole LDR-BT brachytherapy patients were included. Relative to the whole LDR-BT group, the focal/partial LDR-BT group had significantly higher initial PSA level (p = 0.002), smaller number of implanted seeds (p < 0.001), and shorter follow-up duration (p < 0.001). There was no significant difference between the two groups with regard to prostate volume, biopsy Gleason score, and risk group stratification. The 3-year biochemical recurrence-free survival estimates for focal/partial LDR-BT group and whole LDR-BT group were 91.8% and 89.6%, respectively, which was not significantly different (p = 0.554). Genitourinary symptoms were significantly worse in whole LDR-BT group than in focal/partial LDR-BT group. The incidence of rectal toxicity was similar between two groups. CONCLUSIONS: Our findings indicate that the focal/partial LDR-BT is comparable to the whole LDR-BT with respect to short-term biochemical recurrence and toxicities.

Clinical outcomes of hypofractionated radiotherapy for thyroid-associated ophthalmopathy.

OBJECTIVE: To evaluate the safety and effectiveness of hypofractionated orbital radiotherapy applied in the treatment of thyroid-associated ophthalmopathy (TAO) patients. METHODS: Between 2014 and 2018, we retrospectively reviewed the cases of 28 patients with TAO. All patients underwent radiotherapy on both retroocular tissues and received an oral steroid. Patients were divided into two treatment groups: 14 patients received conventional fractionated radiotherapy (20 Gy in 10 fractions), and the second group of 14 patients received hypofractionated radiotherapy (20 Gy in five fractions). The clinical activity score (CAS), NOSPECS (No physical signs or symptoms, Only signs, Soft tissue involvement, Proptosis, Extraocular muscle signs, Corneal involvement, and Sight loss) classification, Hess screen test and binocular single vision (BSV) were evaluated to determine the response to treatment before and at 1 month after radiotherapy. RESULTS: There were no significant differences in any of the variables between the two treatment groups. In both groups, the CAS and NOSPECS score decreased significantly, and the range of extraocular muscle motility in Hess screen test and BSV improved significantly after radiotherapy (p < 0.05). There were no significant differences in CAS, NOSPECS score, Hess screen test or BSV between the two groups. No radiation-related, acute severe toxicity was observed. CONCLUSION: Hypofractionated radiotherapy for TAO produced a comparable clinical outcome to that of conventional fractionated radiotherapy. Further case accumulation and long-term follow-up are required to determine if late toxicity occurs and to confirm efficacy. ADVANCES IN KNOWLEDGE: This is the first study to show that the efficacy and risk of adverse events are comparable between hypofractionated radiotherapy and conventional radiotherapy in the treatment of TAO.

Cryopreserved Human Oocytes and Cord Blood Cells Can Produce Somatic Cell Nuclear Transfer-Derived Pluripotent Stem Cells with a Homozygous HLA Type.

Human pluripotent stem cells (PSCs) through somatic cell nuclear transfer (SCNT) may be an important source for regenerative medicine. The low derivation efficiency of stem cells and the accessibility of human oocytes are the main obstacles to their application. We previously reported that the efficiency of SCNT was increased by overexpression of H3K9me3 demethylase. Here, we applied a modified derivation method to the PSC line and first obtained human SCNT-PSC lines derived from both donated cryopreserved oocytes and cord blood cells with a homozygous human leukocyte antigen (HLA) type. The SCNT-PSCs have very similar characteristics with embryonic stem cells (ESCs) and additionally have shown immunocompatibility in an in vitro and in vivo humanized mouse with a matching HLA type. Our study demonstrates that SCNT technology using donated cryopreserved oocytes and cord blood cells with a known HLA type provides a promising method for establishing a human HLA-matched SCNT-PSC bank for regenerative medicine.

Re-Irradiation and Its Contribution to Good Prognosis in Recurrent Glioblastoma Patients.

BACKGROUND: Radiation therapy, one of the strongest anti-cancer treatments, is already performed to treat primary glioblastoma; however, the effect of repeated radiation therapy for recurrent tumors has not been fully explored. The aim of this study was to determine the efficacy of re-irradiation in treating recurrent glioblastoma. METHODS: The study included 36 patients with recurrent glioblastoma treated with repeated radiation therapy between 2002 and 2016. Stereotactic radiosurgery (SRS) and hypo-fractionated stereotactic radiotherapy (HSRT) were performed in these patients. RESULTS: Fourteen patients received SRS with a median dose of 25 Gy (range, 20-32 Gy) in 1-5 fractions. Twenty-two patients received HSRT with a median dose of 40 Gy (range, 31.5-52 Gy) in 6-20 fractions. There were six treatment-related grade 3 adverse events. Survival analysis showed that re-irradiation significantly prolonged overall survival (OS) and progression-free survival (PFS). The median OS and one-year OS rate after re-irradiation were 17.2 months and 60.4%, respectively. The median PFS and 6-month PFS rate after re-irradiation were 4.4 months and 41.9%, respectively. Of the 36 patients, three survived without any progression in their condition. CONCLUSION: Re-irradiation for recurrent glioblastoma showed favorable outcomes. Radiation dose and fractionation should be carefully considered to minimize radiation necrosis.

New sparse implantation technique of I-125 low-dose-rate brachytherapy using concomitant short-term hormonal treatment for low and intermediate-risk prostate cancer: An initial study of therapeutic feasibility.

This study aimed to evaluate the oncological outcomes and post-implantation complications of the concurrent androgen deprivation therapy (ADT) with I-125 low-dose-rate (LDR)-prostate brachytherapy (sparse implantation technique: SIT) in comparison with the conventional non-ADT using whole gland brachytherapy (CWT). 302 localized prostate cancer (PCa) patients were treated with CWT (implantation dose: 145 Gy) and 215 patients were treated with SIT, which applied reduced implantation dose of 123.5 Gy. SIT group had ADT consisting of bicalutamide 50 mg/day plus 3-month depot (11.25 mg) of leuprolide acetate subcutaneously on the post-implantation day-0. Post-implantation complications and biochemical-recurrence-free-survival (BCRS) were compared between the two groups. After ADT, SIT group had 40.9% patients (40.9%) with prostate volume reduction between 20-30%. At 3-months post-implantation, SIT group presented significantly better IPSS than CWT group (p = 0.038). Both groups showed decrease in IIEF-5 score at 3-months post-implantation, but ST group showed significantly better mean IIEF-5 scores (13.5) than the CWT group (11.1) (p = 0.045). For 3-months post-implantation dosimetry, both groups showed no significant differences regarding D90 (CWT 156 Gy vs. SIT 152 Gy). CWT group had 3 patients with rectal toxicity ≥radiation therapy oncology group (RTOG) grade 2 and 1 patient with urinary toxicity ≥RTOG grade 2 whereas SIT group had no patient with urinary or rectal toxicity ≥RTOG grade 2. Kaplan-Meier analyses showed no significant differences regarding PCSS were observed between the two groups (p = 0.350). The SIT group showed compatible oncological outcomes to the CWT and relatively smaller number of post-implantation complications within low- and intermediate-risk PCa patients.

Tannic acid attenuates the formation of cancer stem cells by inhibiting NF-κB-mediated phenotype transition of breast cancer cells.

Cancer stem cells (CSCs) are innately resistant to standard therapies, which positions CSCs in the focus of anti-cancer research. In this study, we investigated the potential inhibitory effect of tannic acid (TA) on CSCs. Our data demonstrated that TA (10 µM), at the concentration not inhibiting the proliferation of normal mammary cells (MCF10A), inhibited the formation and growth of mammosphere in MCF7, T47D, MDA-MB-231 cells shown as a decrease in mammosphere formation efficiency (MFE), cell number, diameter of mammosphere, and ALDH1 activity. NF-κB pathway was activated in the mammosphere indicated by an up-regulation of p65, a degradation of IκBα, and an increased IL-6. The inhibition of NF-κB pathway via gene silencing of p65 (sip65), NF-κB inhibitor (PDTC), or IKK inhibitor (Bay11-7082) alleviated MFE. Other CSCs markers such as an increase in ALDH1 and CD44high/CD24low ratio were ameliorated by sip65. TA also alleviated TGFß-induced EMT, increase in MFE, and NF-κB activation. In murine xenograft model, TA reduced tumor volume which was associated with a decrease in CD44high/CD24low expression and IKK phosphorylation. These results suggest that TA negatively regulates CSCs by inhibiting NF-κB activation and thereby prevents cancer cells from undergoing EMT and CSCs formation, and may thus be a promising therapy targeting CSCs.

A hepatocyte growth factor/MET-induced antiapoptotic pathway protects against radiation-induced salivary gland dysfunction.

OBJECTIVE: Hepatocyte growth factor (HGF) and its receptor MET are expressed in the salivary glands during developmental stages and tumor formation; however, the function of HGF in injured salivary gland tissues remains unclear. The present study investigated the role of HGF in protecting the salivary glands against radiation-induced injury using an organotypic culture method. MATERIALS AND METHODS: Acinar-like organoids were formed by means of a three-dimensional (3D) human parotid tissue-derived spheroids (hPTS) culture method. Radioprotective effects of HGF on irradiated hPTS and signaling pathways on radioprotection were investigated. RESULTS: We detected MET expression in hPTS grown in a 3D culture. Treatment of irradiated hPTS with recombinant human HGF (rhHGF) restored salivary marker expression and secretory function of hPTS. Changes in the phosphorylation levels of apoptosis-related proteins through HGF-MET axis inhibited radiation-induced apoptosis. Treatment with PHA665752, a MET inhibitor, blocked MET-PI3K-AKT pathway, increased apoptosis, and suppressed the radioprotective effect of rhHGF against IR-induced damage of hPTS. CONCLUSIONS: These results suggest that HGF is a key effector of radioprotection and that HGF-MET-PI3K-AKT axis is involved in protecting the salivary glands from radiation-induced apoptosis.

Is tumor bed boost necessary in patients who achieved ypCR following neoadjuvant chemotherapy and breast conserving therapy? (KROG 12-05 and 16-16).

PURPOSE: This multi-institutional study intended to investigate the effect of tumor bed boost in patients who achieved pathologic complete response (ypCR) following neoadjuvant chemotherapy (NAC) and breast-conserving therapy (BCT). MATERIALS AND METHODS: We identified 180 patients who initially had lymph node (LN) metastasis and achieved ypCR (ypT0/isN0) following NAC and BCT from the 13 institutions of the Korean Radiation Oncology Group (KROG) 16-16 and KROG 12-05. The effect of tumor bed boost on loco-regional control (LRC), disease-free survival (DFS), and overall survival (OS) rates was analyzed. RESULTS: In all patients, five-year LRC, DFS and OS rates were 97.5%, 95.4%, and 99.4%, respectively. Tumor bed boost was performed in 158 (87.8%) patients. Advanced N-stage (cN2-3, p = 0.036), close resection margin (p < 0.001), and sentinel lymph node biopsy (p = 0.040) were unfavorable factors for DFS. Tumor bed boost was not a significant factor for LRC, DFS, and OS. CONCLUSIONS: This study suggests the benefit of tumor bed boost might be minimal in ypCR patients following NAC and BCT. Larger prospective studies are needed to address this issue.

Upregulated microRNA-193a-3p is responsible for cisplatin resistance in CD44(+) gastric cancer cells.

Cisplatin is a well-known anticancer drug used to treat various cancers. However, development of cisplatin resistance has hindered the efficiency of this drug in cancer treatment. Development of chemoresistance is known to involve many signaling pathways. Recent attention has focused on microRNAs (miRNAs) as potentially important upstream regulators in the development of chemoresistance. CD44 is one of the gastric cancer stem cell markers and plays a role in regulating self-renewal, tumor initiation, metastasis and chemoresistance. The purpose of the present study was to examine the mechanism of miRNA-mediated chemoresistance to cisplatin in CD44-positive gastric cancer stem cells. We sorted gastric cancer cells according to level of CD44 expression by FACS and analyzed their miRNA expression profiles by microarray analysis. We found that miR-193a-3p was significantly upregulated in CD44(+) cells compared with CD44(-) cells. Moreover, SRSF2 of miR-193a-3p target gene was downregulated in CD44(+) cells. We studied the modulation of Bcl-X and caspase 9 mRNA splicing by SRSF2 and found that more pro-apoptotic variants of these genes were generated. We also found that downstream anti-apoptotic genes such as Bcl-2 were upregulated, whereas pro-apoptotic genes such as Bax and cytochrome C were downregulated in CD44(+) cells compared to CD44(-) cells. In addition, we found that an elevated level of miR-193a-3p triggered the development of cisplatin resistance in CD44(+) cells. Inhibition of miR-193a-3p in CD44(+) cells increased SRSF2 expression and also altered the levels of multiple apoptotic genes. Furthermore, inhibition of miR-193a-3p reduced cell viability and increased the number of apoptotic cells. Therefore, miR-193a-3p may be implicated in the development of cisplatin resistance through regulation of the mitochondrial apoptosis pathway. miR-193a-3p could be a promising target for cancer therapy in cisplatin-resistant gastric cancer.