Development of Korea Neuroethics Guidelines.

BACKGROUND: Advances in neuroscience and neurotechnology provide great benefits to humans though unknown challenges may arise. We should address these challenges using new standards as well as existing ones. Novel standards should include ethical, legal, and social aspects which would be appropriate for advancing neuroscience and technology. Therefore, the Korea Neuroethics Guidelines were developed by stakeholders related to neuroscience and neurotechnology, including experts, policy makers, and the public in the Republic of Korea. METHOD: The guidelines were drafted by neuroethics experts, were disclosed at a public hearing, and were subsequently revised by opinions of various stakeholders. RESULTS: The guidelines are composed of twelve issues; humanity or human dignity, individual personality and identity, social justice, safety, sociocultural prejudice and public communication, misuse of technology, responsibility for the use of neuroscience and technology, specificity according to the purpose of using neurotechnology, autonomy, privacy and personal information, research, and enhancement. CONCLUSION: Although the guidelines may require a more detailed discussion after future advances in neuroscience and technology or changes in socio-cultural milieu, the development of the Korea Neuroethics Guidelines is a milestone for the scientific community and society in general for the ongoing development in neuroscience and neurotechnology.

Structural and biochemical basis for the substrate specificity of Pad-1, an indole-3-pyruvic acid aminotransferase in auxin homeostasis.

Phytohormone indole-3-acetic acid (IAA) plays a vital role in regulating plant growth and development. Tryptophan-dependent IAA biosynthesis participates in IAA homeostasis by producing IAA via two sequential reactions, which involve a conversion of tryptophan to indole-3-pyruvic acid (IPyA) by tryptophan aminotransferase (TAA1) followed by the irreversible formation of IAA in the second reaction. Pad-1 from Solanaceae plants regulates IAA levels by catalyzing a reverse reaction of the first step of IAA biosynthesis. Pad-1 is a pyridoxal phosphate (PLP)-dependent aminotransferase, with IPyA as the amino acceptor and l-glutamine as the amino donor. Currently, the structural and functional basis for the substrate specificity of Pad-1 remains poorly understood. In this study, we carried out structural and kinetic analyses of Pad-1 from Solanum melongena. Pad-1 is a homodimeric enzyme, with coenzyme PLP present between a central large α/ß domain and a protruding small domain. The active site of Pad-1 includes a vacancy near the phosphate group (P-side) and the 3'-O (O-side) of PLP. These features are distinct from those of TAA1, which is homologous in an overall structure with Pad-1 but includes only the P-side region in the active site. Kinetic analysis suggests that P-side residues constitute a binding pocket for l-glutamine, and O-side residues of Phe124 and Ile350 are involved in the binding of IPyA. These studies illuminate distinct differences in the active site between Pad-1 and TAA1, and provide structural and functional insights into the substrate specificity of Pad-1.

mobileOG-db: a Manually Curated Database of Protein Families Mediating the Life Cycle of Bacterial Mobile Genetic Elements.

Bacterial mobile genetic elements (MGEs) encode functional modules that perform both core and accessory functions for the element, the latter of which are often only transiently associated with the element. The presence of these accessory genes, which are often close homologs to primarily immobile genes, incur high rates of false positives and, therefore, limits the usability of these databases for MGE annotation. To overcome this limitation, we analyzed 10,776,849 protein sequences derived from eight MGE databases to compile a comprehensive set of 6,140 manually curated protein families that are linked to the "life cycle" (integration/excision, replication/recombination/repair, transfer, stability/transfer/defense, and phage-specific processes) of plasmids, phages, integrative, transposable, and conjugative elements. We overlay experimental information where available to create a tiered annotation scheme of high-quality annotations and annotations inferred exclusively through bioinformatic evidence. We additionally provide an MGE-class label for each entry (e.g., plasmid or integrative element), and assign to each entry a major and minor category. The resulting database, mobileOG-db (for mobile orthologous groups), comprises over 700,000 deduplicated sequences encompassing five major mobileOG categories and more than 50 minor categories, providing a structured language and interpretable basis for an array of MGE-centered analyses. mobileOG-db can be accessed at mobileogdb.flsi.cloud.vt.edu/, where users can select, refine, and analyze custom subsets of the dynamic mobilome. IMPORTANCE The analysis of bacterial mobile genetic elements (MGEs) in genomic data is a critical step toward profiling the root causes of antibiotic resistance, phenotypic or metabolic diversity, and the evolution of bacterial genera. Existing methods for MGE annotation pose high barriers of biological and computational expertise to properly harness. To bridge this gap, we systematically analyzed 10,776,849 proteins derived from eight databases of MGEs to identify 6,140 MGE protein families that can serve as candidate hallmarks, i.e., proteins that can be used as "signatures" of MGEs to aid annotation. The resulting resource, mobileOG-db, provides a multilevel classification scheme that encompasses plasmid, phage, integrative, and transposable element protein families categorized into five major mobileOG categories and more than 50 minor categories. mobileOG-db thus provides a rich resource for simple and intuitive element annotation that can be integrated seamlessly into existing MGE detection pipelines and colocalization analyses.

QKI, a miR-200 target gene, suppresses epithelial-to-mesenchymal transition and tumor growth.

The microRNA-200 (miR-200) family plays a major role in specifying epithelial phenotype by preventing expression of the transcription repressors ZEB1 and ZEB2, which are well-known regulators of the epithelial-to-mesenchymal transition (EMT) in epithelial tumors including oral squamous cell carcinoma (OSCC). Here, we elucidated whether miR-200 family members control RNA-binding protein quaking (QKI), a newly identified tumor suppressor that is regulated during EMT. We predicted that miR-200a and miR-200b could recognize QKI 3'-UTR by analyzing TargetScan and The Cancer Genome Atlas head and neck squamous cell carcinoma (HNSCC) dataset. Forced expression of miR-200b/a/429 inhibited expression of ZEB1/2 and decreased cell migration in OSCC cell lines CAL27 and HSC3. QKI expression was also suppressed by miR-200 overexpression, and the 3'-UTR of QKI mRNA was directly targeted by miR-200 in luciferase reporter assays. Interestingly, shRNA-mediated knockdown of QKI led to pronounced EMT and protumor effects in both in vitro and in vivo studies of OSCC. Furthermore, high expression of QKI protein is associated with favorable prognosis in surgically resected HNSCC and lung adenocarcinoma. In conclusion, QKI increases during EMT and is targeted by miR-200; while, it suppresses EMT and tumorigenesis. We suggest that QKI and miR-200 form a negative feedback loop to maintain homeostatic responses to EMT-inducing signals.

Immediate postoperative inflammation is an important prognostic factor in breast cancer.

OBJECTIVE: Inflammation is associated with worse outcomes in cancer. Operations induce an acute inflammatory response and could impact the clinical outcomes in breast cancer. The neutrophil-lymphocyte ratio (NLR) is a well-known indicator of inflammation. We investigated the prognostic significance of perioperative inflammation with the NLR in breast cancer. METHODS: We reviewed the clinical and pathological records of women diagnosed with invasive breast carcinoma at the Samsung Medical Center between 2000 and 2010. The NLR levels in the immediate preoperative period and the postoperative periods (1 week and 1 month) were assessed. RESULTS: The NLRs of a total of 3,116 breast cancer patients were examined. In the univariate analysis, the NLR in postoperative week 1, total mastectomy, the presence of lymphovascular invasion, a higher nuclear grade and pathologic TNM stage, and negative hormone receptor and subtypes were factors associated with poor disease-specific survival. The NLR in postoperative week 1 remained a significant prognostic factor in the multivariate analysis. A cutoff level of 5.2, determined by the minimum p value approach, was found to be a significant level for discriminating the impact on breast cancer-specific mortality (p = 0.0116 adjusted by the Bonferroni correction). CONCLUSIONS: Immediate postoperative inflammation is an important prognostic marker in breast cancer patients.

Effects of water-saving irrigation on emissions of greenhouse gases and prokaryotic communities in rice paddy soil.

The effects of water-saving irrigation on emissions of greenhouse gases and soil prokaryotic communities were investigated in an experimental rice field. The water layer was kept at 1-2 cm in the water-saving (WS) irrigation treatment and at 6 cm in the continuous flooding (CF) irrigation treatment. WS irrigation decreased CH(4) emissions by 78 % and increased N(2)O emissions by 533 %, resulting in 78 % reduction of global warming potential compared to the CF irrigation. WS irrigation did not affect the abundance or phylogenetic distribution of bacterial/archaeal 16S rRNA genes and the abundance of bacterial/archaeal 16S rRNAs. The transcript abundance of CH(4) emission-related genes generally followed CH(4) emission patterns, but the difference in abundance between mcrA transcripts and amoA/pmoA transcripts best described the differences in CH(4) emissions between the two irrigation practices. WS irrigation increased the relative abundance of 16S rRNAs and functional gene transcripts associated with Anaeromyxobacter and Methylocystis spp., suggesting that their activities might be important in emissions of the greenhouse gases. The N(2)O emission patterns were not reflected in the abundance of N(2)O emission-related genes and transcripts. We showed that the alternative irrigation practice was effective for mitigating greenhouse gas emissions from rice fields and that it did not affect the overall size and structure of the soil prokaryotic community but did affect the activity of some groups.

Risk factors associated with the survival of endodontically treated teeth: A retrospective chart review.

BACKGROUND: Studies on risk factors affecting tooth retention after endodontic treatment in dental school settings are limited. Understanding these factors is crucial for preserving teeth. The aim of this retrospective study was to evaluate patient- and tooth-level risk factors associated with the survival of endodontically treated teeth. METHODS: Electronic health records of patients who underwent endodontic treatment at the School of Dental Medicine at the University of Pennsylvania from 2017 through 2020 were analyzed. Patient-level factors included age, sex, American Society of Anesthesiologists Physical Status Classification, smoking history, diabetes status, and amoxicillin allergy. Tooth-level factors included position, presence of restorations, and periodontal conditions with preprosthetic treatments. RESULTS: The results of this study indicate that the patient-level factors significantly associated with tooth retention included age, sex, American Society of Anesthesiologists Physical Classification Status, and amoxicillin allergy. Tooth-level factors such as core buildup, full-coverage crown, healthy periodontium, and scaling and root planing were also associated with higher survival rates. Mandibular premolars had higher survival rates than mandibular molars. CONCLUSIONS: This investigation revealed that the tooth retention rate of endodontically treated teeth was 96.2% after initial root canal treatment, 92.4% for nonsurgical re-treatment, and 97.8% for surgical re-treatment. PRACTICAL IMPLICATIONS: The tooth retention of the endodontic treatment was associated with healthy periodontium, tooth structure, tooth position, tooth restoration, and the patient's overall health.

Modulating Lipid Nanoparticles with Histidinamide-Conjugated Cholesterol for Improved Intracellular Delivery of mRNA.

Recently, mRNA-based therapeutics, including vaccines, have gained significant attention in the field of gene therapy for treating various diseases. Among the various mRNA delivery vehicles, lipid nanoparticles (LNPs) have emerged as promising vehicles for packaging and delivering mRNA with low immunogenicity. However, while mRNA delivery has several advantages, the delivery efficiency and stability of LNPs remain challenging for mRNA therapy. In this study, an ionizable helper cholesterol analog, 3ß[L-histidinamide-carbamoyl] cholesterol (Hchol) lipid is developed and incorporated into LNPs instead of cholesterol to enhance the LNP potency. The pKa values of the Hchol-LNPs are ≈6.03 and 6.61 in MC3- and SM102-based lipid formulations. Notably, the Hchol-LNPs significantly improve the delivery efficiency by enhancing the endosomal escape of mRNA. Additionally, the Hchol-LNPs are more effective in a red blood cell hemolysis at pH 5.5, indicating a synergistic effect of the protonated imidazole groups of Hchol and cholesterol on endosomal membrane destabilization. Furthermore, mRNA delivery is substantially enhanced in mice treated with Hchol-LNPs. Importantly, LNP-encapsulated SARS-CoV-2 spike mRNA vaccinations induce potent antigen-specific antibodies against SARS-CoV-2. Overall, incorporating Hchol into LNP formulations enables efficient endosomal escape and stability, leading to an mRNA delivery vehicle with a higher delivery efficiency.

HER3 status by immunohistochemistry is correlated with poor prognosis in hormone receptor-negative breast cancer patients.

Breast cancer is a highly heterogeneous malignancy. The triple-negative breast cancer (TNBC) and human epidermal growth factor receptor 2 (HER2) breast cancer subtypes are highly aggressive and are associated with a poor prognosis. The therapeutic targets for TNBC remain undefined, and many patients with the HER2 subtype acquire resistance to therapy after prolonged treatment. The objective of this study was to evaluate the prognostic significance of HER3 expression in invasive breast carcinoma. We established matched tissue microarray (TMA) blocks and clinical data from 950 cases of invasive breast carcinoma with long-term clinical follow-up data (median 109.7 months). Using the TMAs, we characterized the expression of ER, PR, HER2, EGFR, and HER3 by immunohistochemistry. Each case was classified as one of four IHC-based subtypes based on the expression of hormonal receptor (HR) and HER2. The clinicopathological characteristics and survival of 950 patients were analyzed by subtype. In the TNBC subtype, the HER3(+) group showed poorer disease-free survival (DFS, P = 0.010) and overall survival (OS, P = 0.015) than the HER3(-) group. In the HER2 subtype, the HER3(+) group also showed poorer DFS (P = 0.022) and OS (P = 0.077) than the HER3(-) group. However, there was no difference in patients with HR-positive breast cancer. HER3 expression was associated with poor DFS in both the TNBC and HER2 subtypes and poor OS in the TNBC subtype. HER3 overexpression is an important prognostic marker in hormone receptor-negative breast cancer, and further study is needed to clarify the role of HER-3 targeted treatment.

Round block technique without cerclage in breast-conserving surgery.

BACKGROUND: Round block technique is a unique breast resection through periareolar doughnut incision. However, it is more technically challenging and time consuming. We simplified the procedure by exclusion of round block cerclage. The purpose of this study was to introduce our round block technique without cerclage and to evaluate the results of oncological and cosmetic outcomes. METHODS: A total of 92 patients with centrally located breast cancer were treated with breast-conserving surgery using round block technique at Samsung Medical Center from July 2009 to May 2012. All patients had a small breast defect with excised breast volume less than 20 % compared to the total breast volume. We minimized the extent of skin removal and used simple interrupted inverted intradermal sutures without cerclage in doughnut closure. Patient's cosmetic satisfaction was assessed by subjective questionnaires at least 6 months after the operation. RESULTS: The median size of tumors was 1.7 cm (range 0.5-5.0 cm). The average distance of the tumors from the nipple was 2.0 cm (range 0.0-4.0 cm) on sonogram and most of the tumors were located upper breast (82.6 %). The median operative time was 101.5 min (range 55-180), including axillary surgeries. Median follow-up was 12.0 months (range 2-36), and none of patients have developed local recurrence. Up to the longest 3 years of follow-up, favorable cosmetic results have been found in patients treated with round block technique. CONCLUSIONS: Round block without cerclage is technically easy and feasible for centrally located breast tumors with favorable cosmetic results.

A new subfascial approach in open thyroidectomy: efficacy for postoperative voice, sensory, and swallowing symptoms. A randomized controlled study.

BACKGROUND: After open thyroidectomy, patients usually complain of voice, sensory, and swallowing symptoms. We approached the thyroid via the subfascial method to reduce these symptoms and compared postthyroidectomy symptoms with the conventional subplatysmal method. METHODS: Eighty-six patients undergoing thyroidectomy were recruited and randomized into either a conventional subplatysmal approach group (subplatysmal, 42 patients) group or a subanterior fascia of strap muscle approach group (subfascial, 44 patients). Voice symptoms were assessed using the Voice Handicap Index questionnaire and acoustic voice analysis. Sensory alterations were evaluated by the light touch and pain touch methods. Swallowing symptoms were assessed using the Swallowing Impairment Score (SIS) questionnaire, barium swallowing time, and hyoid bone movement range. Each variable was measured preoperatively, and at 2 weeks and 3 months after thyroidectomy. RESULTS: In both groups, the subjective symptoms of voice, sensation, and swallowing were significantly worsened at 2 weeks after operation, but improved 3 months after operation. Patients in the subplatysmal group had worse SIS scores than patients in the subfascial group (p = 0.016) and delayed barium swallowing time 2 weeks after operation (p = 0.008 compared to preoperative level). In the cohort over 50 years of age, SIS score did not recover to preoperative levels in the subplatysmal group 3 months after operation (p = 0.005 compared to preoperative level). CONCLUSIONS: The subfascial approach may be an effective method for reducing postthyroidectomy swallowing symptoms based on swallowing impairment score, especially in patients over 50 years of age.

The clinical meaning of intramammary lymph nodes.

OBJECTIVE: The clinical meaning of intramammary lymph nodes (iMLNs) is uncertain. We wanted to describe the clinical characteristics and understand the implications of iMLNs detected by sentinel LN biopsy (SLNB). METHODS: We reviewed the clinical, radiological and pathological records of women diagnosed with invasive carcinoma of the breast at the Samsung Medical Center between January 2001 and January 2011. A total of 69 patients were identified, and SLNB was performed in 31 patients. RESULTS: Of the 69 patients included in the study, 22 (31.9%) had metastases in iMLNs. The presence of lymphovascular invasion and the number of axillary LN metastases were associated with iMLN metastasis. Of the 31 patients who underwent SLNB, there were no cases with axillary LN metastasis when axillary SLNB was negative, even in cases of iMLN-positive patients. Of the 10 patients in whom intramammary SLNs (iMSLNs) were detected during SLNB, 8 patients without iMLN metastases were also negative for axillary LNs. CONCLUSION: Patients with metastatic iMLNs had more aggressive cancers with lymphovascular invasion and increased axillary LN metastases. When iMSLN was detected by SLNB, performing of axillary dissection could be determined by the status of the iMSLN itself.

Oncogenic KRAS mutation confers chemoresistance by upregulating SIRT1 in non-small cell lung cancer.

Kirsten rat sarcoma viral oncogene homologue (KRAS) is a frequent oncogenic driver of solid tumors, including non-small cell lung cancer (NSCLC). The treatment and outcomes of KRAS-mutant cancers have not been dramatically revolutionized by direct KRAS-targeted therapies because of the lack of deep binding pockets for specific small molecule inhibitors. Here, we demonstrated that the mRNA and protein levels of the class III histone deacetylase SIRT1 were upregulated by the KRASMut-Raf-MEK-c-Myc axis in KRASMut lung cancer cells and in lung tumors of a mouse model with spontaneous KrasG12D expression. KRASMut-induced SIRT1 bound to KRASMut and stably deacetylated KRASMut at lysine 104, which increased KRASMut activity. SIRT1 knockdown (K/D) or the SIRT1H363Y mutation increased KRASMut acetylation, which decreased KRASMut activity and sensitized tumors to the anticancer effects of cisplatin and erlotinib. Furthermore, in KrasG12D/+;Sirt1co/co mice, treatment with cisplatin and erlotinib robustly reduced the tumor burden and increased survival rates compared with those in spontaneous LSL-KrasG12D/+;Sirt1+/+ mice and mice in each single-drug treatment group. Then, we identified p300 as a KRASMut acetyltransferase that reinforced KRASMut lysine 104 acetylation and robustly decreased KRASMut activity. KRASMut lysine 104 acetylation by p300 and deacetylation by SIRT1 were confirmed by LC‒MS/MS. Consistent with this finding, the SIRT1 inhibitor EX527 suppressed KRASMut activity, which synergistically abolished cell proliferation and colony formation, as well as the tumor burden in KRASMut mice, when combined with cisplatin or erlotinib. Our data reveal a novel pathway critical for the regulation of KRASMut lung cancer progression and provide important evidence for the potential application of SIRT1 inhibitors and p300 activators for the combination treatment of KRASMut lung cancer patients.

Comparison between screen-detected and symptomatic breast cancers according to molecular subtypes.

Breast cancer screening programs make it possible to detect early cancer, thus reducing breast cancer mortality. We studied the clinicopathologic characteristics and prognosis of screen-detected invasive breast cancer compared with symptomatic breast cancer. And we compared the result according to molecular subtypes (luminal A, luminal B, Her2, and triple negative), with the goal of identifying the role of screening in each subtypes. From January 2002 to June 2008, 3,141 patients who underwent surgery for the treatment of invasive ductal carcinoma at Samsung Medical Center were included. Among them, 1,025 patients were screen-detected, and 2,116 patients who were screened over 2 years or never were symptomatic. We retrospectively reviewed the clinical and pathologic data. Screen-detected breast cancer was associated with older age, smaller tumor size, more hormone-receptor positive, less lymph node involvement, earlier stage, and reduced mortality compared with symptomatic breast cancer (P < 0.001). According to the molecular subtype, luminal A was most common (63.6%) and showed the most obvious survival benefit in screen-detected tumors in comparison with symptomatic tumors (5-year OS: 99.7 vs. 96.5%, 5-year DFS: 96.4 vs. 90.7%). Screen detection was independently associated with improved overall and disease-free survival outcomes after adjustment for covariates (HR 0.32, P = 0.035; HR 0.58, P = 0.020, respectively) only in the luminal A subtype. Differences in pathological features such as tumor size, nodal status, grade, and age at diagnosis with different molecular subtype distributions may explain the survival advantage of patients with screen-detected breast cancer. Screening programs seem to have a different efficacy depending on the molecular subtype of the breast cancer, especially in the luminal A subtype, for which screen detection acts as an independent prognostic factor itself.

Right paraesophageal lymph node dissection in papillary thyroid carcinoma.

BACKGROUND: This study was designed to identify the patients with papillary thyroid carcinoma (PTC) who would benefit from RPELN dissection. SUMMARY BACKGROUND DATA: The value of the right paraesophageal lymph nodes (RPELNs), which are located posterior to the right recurrent laryngeal nerve, may be underestimated. Although the RPELNs are common sites of nodal recurrence, few related studies have been reported. METHODS: We retrospectively reviewed the medical records of 369 patients (286 female, 83 male) who underwent total thyroidectomy (327 patients) or right lobectomy (42 patients) with therapeutic or prophylactic central lymph node dissection for primary PTC between August 2008 and January 2010 at the Department of Surgery, Samsung Medical Center. RESULTS: Central lymph node (CLN) metastases were present in 51.2% (189 of 369) of the patients, and RPELN metastases were present in 12.2% (45 of 369) of the patients. The rate of RPELN metastasis was 19.6% (37 of 189) in patients with CLN metastases, but only 4.4% (8 of 180) in patients with no CLN metastases (P < .001). A univariate analysis revealed that RPELN metastasis was significantly correlated with the size of the tumor, the perithyroidal extent (capsular invasion), CLN metastasis, and lateral lymph node metastases. There were no significant differences in terms of gender, mean age, or number of tumors between groups. A multivariate analysis revealed that tumor size (>1 cm) and number of CLN metastases (≥ 3) were significantly correlated with RPELN metastasis. CONCLUSIONS: RPELN dissection should be considered in patients with right thyroid cancer, tumors larger than 1 cm, or multiple CLN metastases.

Clinicopathologic risk factors for the local recurrence of phyllodes tumors of the breast.

BACKGROUND: Phyllodes tumors (PTs) are rare breast tumors that usually occur in middle-aged women. Here we discuss our recent experiences in the diagnosis, surgical management, and clinical follow-up of this disease. METHODS: We retrospectively reviewed 164 patients with PTs who underwent surgical treatment at the Department of Surgery, Samsung Medical Center, Seoul, Korea, from January 1995 to July 2009. Clinical and histopathological data were analyzed. RESULTS: The median follow-up period was 33.6 months (range 2-179 months), and the median patient age was 43 years (range of 11-72 years). Tumor size ranged from 1 to 30 cm, with a median of 6.1 cm. A total of 148 patients (90.2 %) received local or wide excisions. Mastectomies were performed in 16 patients (9.8 %). The pathologic diagnoses included 82 benign (50.0 %), 42 borderline (25.6 %), and 40 malignant PTs (24.4 %). The tumor border was infiltrating in 43 patients (26.2 %) and pushing in 116 patients (70.7 %). The resection margin was divided by based on the width. Local recurrence was observed in 31 patients (18.9 %), and distant metastasis developed in four patients with malignant PTs. Risk factors for the local recurrence of a PT were a positive resection margin (P = .029) and tumor size (P = .001). CONCLUSIONS: The presence of tumor cells on the resection margin was a strong prognostic factor for local recurrence of PTs. However, a 1 cm negative margin thickness did not confer any local control advantage over a thinner negative margin width.

Lymph node metastasis in patients with frozen section analyses that are negative for tumors.

OBJECTIVES: This study was designed to assess the necessity of delayed complete axillary lymph node dissection (cALND) for patients whose sentinel lymph nodes (SLNs) were negative for tumors on intraoperative frozen section analysis, but later proven positive on hematoxylin and eosin staining or immunohistochemistry. METHODS: We identified 341 patients who underwent sentinel lymph node biopsy (SLNB) with cALND at the Samsung Medical Center between 1998 and 2008, and reviewed the clinicopathological records of women diagnosed with invasive carcinoma of the breast. RESULTS: Of the 341 patients, 59 underwent delayed cALND due to negative results on frozen section. Only 1 patient had a non-SLNs metastasis in the group of delayed cALND. Delayed cALND was associated with higher rates of breast-conserving surgery, smaller primary tumor and metastasis size in SLNs, fewer metastatic lymph nodes and SLNs and a lower TNM stage. The detection of metastases of SLNs on frozen section and the number of metastatic SLNs were related to the detection of additional metastases of nonsentinel lymph nodes (NSLNs) in cALND. CONCLUSION: Our findings suggest that the lack of detection of metastases on frozen sections may be a predictive factor for nonmetastasis in NSLNs. cALND could therefore be omitted in such cases.

Berberine suppresses the TPA-induced MMP-1 and MMP-9 expressions through the inhibition of PKC-α in breast cancer cells.

BACKGROUND: Berberine (BBR) is one of the major alkaloids, and it has been reported to have a variety of pharmacologic effects, including inhibition of cell cycle progression. Here, we investigated the effect of BBR on the MMP-1 and MMP-9 expressions, which are predictors of metastasis and invasion in breast cancer cells. METHODS: MMP-1 and MMP-9 mRNA expressions were analyzed by real-time PCR. The levels of MMP-1 protein and PKC-α phosphorylation were detected by Western blotting. MMP-9 protein expression was detected by gelatin zymography. Cell cycle was analyzed by FACS analysis. PKC-α knock-down was examined by PKC-α siRNA transfection. RESULTS: The basal levels of both the MMP-1 and MMP-9 mRNA expressions were decreased by BBR treatment in a dose-dependent manner. In contrast, TPA, which is a tumor promoter, significantly increased the levels of the MMP-1 and MMP-9 mRNA and protein expressions in the MCF-7 breast cancer cells. We also observed that the TPA-induced MMP-1 and MMP-9 mRNA and protein expressions were prevented by BBR treatment. In addition, the TPA-induced MMP-1 and MMP-9 expressions were completely decreased by Go6983 and PKC-α siRNA, respectively. TPA-induced PKC-α phosphorylation was dose-dependently decreased by BBR treatment. CONCLUSION: The TPA-induced PKC-α phosphorylation is suppressed and then the MMP-1 and MMP-9 expressions are also inhibited by berberine. Therefore, we suggest that berberine may be used as a candidate drug for the inhibition of metastasis of human breast cancer.

Preparation and characterization of polyamidoamine dendrimers conjugated with cholesteryl-dipeptide as gene carriers in HeLa cells.

Improving the transfection efficiency of non-viral carriers by using cationic polymers is a useful approach to addressing several challenges in gene therapy, such as cellular uptake, endosomal escape, and toxicity. Among the various cationic polymers, polyamidoamine (PAMAM) dendrimers have been widely utilized because of the abundance of terminal functional groups, thereby enabling further functionalization and enhancing DNA condensation and internalization into cells. The combination of various functional groups is required for these PAMAM dendrimer derivatives to function appropriately for gene delivery. Herein, we synthesized PAMAM G2-HRChol by conjugating dipeptide (histidine-arginine) and cholesterol at different ratios (6% or 23%) on the surface of PAMAM dendrimer generation 2 (PAMAM G2). Both PAMAM G2-HRChol 6% and PAMAM G2-HRChol 23% have buffering capacity, leading to improved endosomal escape after entering the cells. PAMAM G2-HRChol 6% and PAMAM G2-HRChol 23% dendrimers were condensed with pDNA to form nano-polyplexes at a weight ratio of 4 (polymer/pDNA). Polyplexes are positively charged, which facilitates cellular uptake. The transfection efficiency of PAMAM G2-HRChol 6% and PAMAM G2-HRChol 23% dendrimers was similar to that of PEI 25 kDa under optimum conditions, and the cytotoxicity was much lower than that of PEI 25 kDa in HeLa cells. In addition, after apoptin gene transfection was performed, cell death ratios of 34.47% and 22.47% were observed for PAMAM G2-HRChol 6% and PAMAM G2-HRChol 23%, respectively. The results show that a suitable amount of cholesterol can improve gene transfection efficiency, and the PAMAM G2-HRChol 6% dendrimer could be a potential gene carrier in HeLa cells.

Oncogenic KRAS promotes growth of lung cancer cells expressing SLC3A2-NRG1 fusion via ADAM17-mediated shedding of NRG1.

We previously found the SLC3A2-NRG1 (S-N) fusion gene in a lung adenocarcinoma specimen without known driver mutations and validated this in 59 invasive mucinous adenocarcinoma (IMA) samples. Interestingly, KRAS mutation coexisted (62.5%) in 10 out of 16 NRG1 fusions. In this study, we examined the role of mutant KRAS in regulating the S-N fusion protein in KRAS mutant (H358) and wild-type (Calu-3) cells. KRAS mutation-mediated increase in MEK1/2 and ERK1/2 activity enhanced disintegrin and metalloproteinase (ADAM)17 activity, which increased the shedding of NRG1 from the S-N fusion protein. The cleavage of NRG1 also increased the phosphorylation of ERBB2-ERBB3 heterocomplex receptors and their downstream signalling pathways, including PI3K/Akt/mTOR, even under activated KRAS mutation signalling. The concurrence of S-N fusion and KRAS mutation synergistically increased cell proliferation, colony formation, tumour growth, and the cells' resistance to EGFR kinase inhibitors more than KRAS mutation alone. Targeted inhibition of MEK1/2, and ADAM17 significantly induced apoptosis singly and when combined with each mutation singly or with chemotherapy in both the concurrent KRAS mutant and S-N fusion xenograft and lung orthotopic models. Taken together, this is the first study to report that KRAS mutation increased NRG1 cleavage from the S-N fusion protein through ADAM17, thereby enhancing the Ras/Raf/MEK/ERK and ERBB/PI3K/Akt/mTOR pathways. Moreover, the coexistence of KRAS mutant and S-N fusion in lung tumours renders them vulnerable to MEK1/2 and/or ADAM17 inhibitors, at least in part, due to their dependency on the strong positive loop between KRAS mutation and S-N fusion.