Phenomenological interpretations of the mechanism for the concentration-dependent positive effect of antibiotic lincomycin on Streptomyces coelicolor A3(2).

The antibiotic lincomycin binds to the 23S ribosomal RNA peptidyl transferase loop region to inhibit protein synthesis. However, lincomycin can also stimulate the growth and secondary metabolism of actinomycetes in a concentration-dependent manner. In Streptomyces coelicolor A3(2), lincomycin stimulates the production of the blue-pigmented antibiotic actinorhodin at concentrations below the minimum inhibitory concentration. To better understand the molecular mechanism underlying these concentration-dependent positive effects, this study investigated how the target molecule, the ribosome, undergoes dynamic changes in the presence of lincomycin and explored the ribosome-related factors involved. Lincomycin, at a concentration that stimulates actinorhodin production of S. coelicolor A3(2), could restore temporarily arrested ribosome function by utilizing ribosome-related proteins and translation factors, presumably under the control of the transcription factor WblC protein that confers intrinsic resistance to multiple translation-inhibiting antibiotics, to eventually produce stable and active ribosomes even during the late growth phase. This qualitatively and quantitatively positive ribosome alteration can be advantageous for producing actinorhodin biosynthetic enzymes. A series of gene expression and biochemical analyses revealed that lincomycin at the concentration that induces ribosomal stabilization in S. coelicolor A3(2) could influence the localization of the 20S proteasome-related proteins, resulting in reduced proteasome activity. These findings suggest that the functional analysis of 20S proteasome represents a potential pivotal challenge for understanding the molecular mechanism of ribosome stabilization induced by lincomycin. Therefore, as lincomycin can dynamically alter its target molecule, the ribosome, we discuss the future issues and prospects for an increased understanding of the concentration-dependent properties of antibiotics. IMPORTANCE Antibiotics were originally defined as chemical compounds produced by a microbe that inhibits the growth of other microbes. However, an unexplained effect of this is that a low concentration of antibiotics, such as those below the minimum inhibitory concentration, can positively affect microbial growth and metabolism. The secondary metabolic activation of streptomycetes in the presence of the translation-inhibiting antibiotic lincomycin illustrates the concentration-dependent positive effect of the antibiotic. The significance of this study is that the phenomenological interpretation of the molecular mechanism of the concentration-dependent positive effect of lincomycin in Streptomyces coelicolor A3(2) has provided novel insight into the possible role of antibiotics in making their target molecules stable and active with the assistance of various related factors that benefit their function. Further exploration of this idea would lead to an essential understanding of antibiotics, including why actinomycetes make them and their role in nature.

Serial circulating tumor DNA monitoring of CDK4/6 inhibitors response in metastatic breast cancer.

Cyclin-dependent kinase 4/6 inhibitors (CDK4/6i) significantly improve progression-free survival and have become the standard therapy for estrogen receptor-positive/human epidermal growth factor receptor 2-negative metastatic breast cancer patients. Treatment surveillance by radiological imaging has some limitations in detection and repeated biopsy genomic profiling is not clinically feasible. Serial circulating tumor DNA (ctDNA) analysis may provide insights into treatment response. Here we performed serial ctDNA analysis (n = 178) on 33 patients. Serial ctDNA analysis identified disease progression with sensitivity of 75% and specificity of 92%. In eight of 12 patients (61%) responding to CDK4/6i who eventually developed progressive disease, serial sampling every 3 or 6 months captured the initial rise of ctDNA with an average lead time of 3 months. In three of eight patients that did not respond to CDK4/6i (progressive disease at first radiological assessment, 3 months), biweekly sequencing within the first cycle of CDK4/6i treatment (1 month) detected sustained ctDNA levels (≥0.2% variant allele frequency), with lead time of 2 months. Serial ctDNA analysis tracked RECIST response, including clinically challenging scenarios (bone metastases or small-sized target lesions), as well as detecting acquired genetic alterations linked to CDK4/6i resistance in the G1 to S transition phase. Circulating tumor DNA analysis was more sensitive than carcinoembryonic antigen or cancer antigen 15-3 serum tumor markers at monitoring tumor response to CDK4/6i treatment. Our findings indicated the possible clinical utility of serial ctDNA analysis for earlier progressive disease detection and real-time monitoring of CDK4/6i response.

Trastuzumab and fulvestrant combination therapy for women with advanced breast cancer positive for hormone receptor and human epidermal growth factor receptor 2: a retrospective single-center study.

BACKGROUND: Trastuzumab and fulvestrant combination therapy is one of the treatment options for patients with hormone receptor- and human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer; however, there are limited studies evaluating the efficacy of this combination therapy. METHODS: We retrospectively reviewed the data of women with hormone receptor- and HER2-positive metastatic breast cancer who received trastuzumab and fulvestrant combination therapy between August 1997 and August 2020 at the Cancer Institute Hospital. The primary endpoint of this study was progression-free survival, and the secondary endpoints were response rate, overall survival and safety. RESULTS: We reviewed the data of 1612 patients with recurrent or metastatic breast cancer, of which 118 patients were diagnosed with hormone receptor- and HER2-positive breast cancer. Of these, 28 patients who received trastuzumab and fulvestrant combination therapy were eligible for this study. The median treatment line for advanced breast cancer was 6 (range, 1-14), the median progression-free survival was 6.4 months (95% confidence interval [CI], 3.46-8.17), and the median overall survival was 35.3 months (95% CI, 20.0-46.7). Of the 28 patients, partial response was observed in 1 (4%), stable disease in 17 (61%), and progressive disease in 10 (36%) patients. The disease control rate was 64%. Adverse events of grade ≥ 3 were not observed. CONCLUSIONS: Trastuzumab and fulvestrant combination therapy showed moderate clinical efficacy and no severe toxicity after standard anti-HER2 treatment, which is a reasonable treatment option for patients with hormone receptor- and HER2-positive metastatic breast cancer. These data contribute to understanding the efficacy of trastuzumab and fulvestrant combination therapy as control data for further development of anti-HER2 agents plus hormone therapy.

Ultradeep targeted sequencing of circulating tumor DNA in plasma of early and advanced breast cancer.

We present a study to evaluate the feasibility and clinical utility of amplicon-based Oncomine Pan-Cancer cell-free assay to detect circulating tumor DNA (ctDNA) in patients with early or advanced breast cancer. In this study, 109 early and metastatic breast cancer patients were recruited before the initiation of treatment. ctDNA mutation profiles were assessed through unique molecular tagging (UMT) and ultradeep next generation sequencing (NGS). For patients with mutations, DNA from corresponding white blood cells (WBC) was sequenced to exclude variants of clonal-hematopoietic (CH) origin. UMT targeted sequencing from plasma of 109 patients achieved a median total coverage of 55 498X and a median molecular coverage of 4187X. Among 53 ctDNA positive samples, 38% were mutation positive by WBC sequencing, indicating potentially false-positive results contributed by CH origin. Prevalence of CH-related mutations was associated with age (P = 7.51 × 10-4 ). After exclusion of CH mutations, ctDNA detection rates were 37% for local or locally advanced breast cancer (stage I-III) and 81% for metastatic or recurrent breast cancer. The ctDNA detection rate correlated with disease stage (P = 2.60 × 10-4 ), nodal spread (P = 6.49 × 10-3 ) and the status of distant metastases (P = 5.00 × 10-4 ). ctDNA variants were detected mostly in TP53, PIK3CA and AKT1 genes, with variants showing therapeutic relevance. This pilot study endorses the use of targeted NGS for non-invasive molecular profiling of breast cancer. Paired sequencing of plasma ctDNA and WBC should be implemented to improve accurate interpretation of liquid biopsy.

Clinical significance of gene mutation in ctDNA analysis for hormone receptor-positive metastatic breast cancer.

PURPOSE: In this study, we aim to investigate the mutation spectrum of circulating tumor DNA among hormone receptor-positive metastatic breast cancer (HR-MBC) patients using ultradeep targeted resequencing. In addition, we also evaluate the correlation of mutations detected from this study with progression-free survival (PFS). MATERIALS AND METHODS: A total of 56 HR-MBC patients were enrolled. Cell-free DNA (cfDNA) was extracted from plasma and sequenced by using Oncomine Breast cancer cfDNA assay in this study. RESULT: Concentration of cfDNA is correlated with a number of metastatic organs and serum CEA levels (Spearman's rank correlation p = 0.0018, p = 0.0015 respectively). Cases with high cfDNA levels (≥ 2.6 ng/µl of plasma) showed worse progression-free survival (PFS) and overall survival compared with cases with low cfDNA levels (p = 0.043 and 0.046, respectively). Among these patients, 29 patients (51.7%) have TP53 mutations, 12 patients (30.3%) have PIK3CA mutations, and 9 patients (16.0%) have ESR1 mutations. Acquisition of ESR1 mutation increased according to the lines of hormone therapy. In addition, patients with ESR1 mutation showed shorter PFS than those without mutation (log-rank p = 0.047). In the multivariate analysis, ESR1 mutation and cfDNA concentration were significant for PFS (p = 0.027 and 0.006, respectively). In conclusion, assessment of ESR1 mutation and cfDNA concentration could be useful in predicting prognosis for HR-MBCs.

Experiences of intimate partner violence as perpetrated among Japanese university freshmen.

Objectives: To compare experiences regarding the perpetration of intimate partner violence among Japanese university freshmen between 2008 and 2014. Study design: Two-stage cross-sectional study. Methods: A self-administered questionnaire survey was completed in both 2008 and 2014 by students at the same university. Results: There were significant reductions in episodes of verbal harassment (adjusted odds ratio [AOR]: 0.601, 95% confidence interval [CI]: 0.382, 0.945, P = 0.027) that occurred when a boy/girlfriend said "you don't give me priority" to his/her partner when they did not see them (AOR: 0.450, 95%CI: 0.207, 0.979, P = 0.044), and also in instances of irritation that resulted when a boy/girlfriend disobeyed his/her partner (AOR: 0.385, 95%CI: 0.161, 0.921, P = 0.032) from 2008 to 2014. The perpetration scores were reduced from 1.87 ±â€…0.16 in 2008 to 1.41 ±â€…0.117 in 2014 (t test, P = 0.016). The perpetration scores in 2014 were significantly lower than those in 2008, regardless of gender, age, university faculty, and participation in lectures/seminars about domestic violence (DV) and/or dating DV (P = 0.030). Conclusions: Findings showed reductions in some types of harassment, as well as in perpetration scores, between 2008 and 2014 among Japanese university freshmen at the same university. However, further study is required to determine the factors related to the perpetration of harassment.

Pattern of Tumor Shrinkage during Neoadjuvant Chemotherapy Is Associated with Prognosis in Low-Grade Luminal Early Breast Cancer.

Purpose To evaluate the association between tumor shrinkage patterns shown with magnetic resonance (MR) imaging during neoadjuvant chemotherapy (NAC) and prognosis in patients with low-grade luminal breast cancer. Materials and Methods This retrospective study was approved by the institutional review board and informed consent was obtained from all subjects. The low-grade luminal breast cancer was defined as hormone receptor-positive and human epidermal growth factor receptor 2-negative with nuclear grades 1 or 2. The patterns of tumor shrinkage as revealed at MR imaging were categorized into two types: concentric shrinkage (CS) and non-CS. Among 854 patients who had received NAC in a single institution from January 2000 to December 2009, 183 patients with low-grade luminal breast cancer were retrospectively evaluated for the development set. Another data set from 292 patients who had received NAC in the same institution between January 2010 and December 2012 was used for the validation set. Among these 292 patients, 121 patients with low-grade luminal breast cancer were retrospectively evaluated. Results In the development set, the median observation period was 67.9 months. Recurrence was observed in 31 patients, and 16 deaths were related to breast cancer. There were statistically significant differences in both the disease-free survival (DFS) and overall survival (OS) rates between patterns of tumor shrinkage (P < .001 and P < .001, respectively). Multivariate analysis demonstrated that the CS pattern had the only significant independent association with DFS (P = .001) and OS (P = .009) rate. In the validation set, the median follow-up period was 56.9 months. Recurrence was observed in 20 patients (16.5%) and eight (6.6%) deaths were related to breast cancer. DFS rate was significantly longer in patients with the CS pattern (72.8 months; 95% confidence interval [CI]: 69.9, 75.6 months) than in those with the non-CS pattern (56.0 months; 95% CI: 49.1, 62.9 months; P ≤ .001). The CS pattern was associated with an excellent prognosis (median OS, 80.6 months; 95% CI: 79.3, 81.8 months vs 65.0 months; 95% CI: 60.1, 69.8 months; P = .004). Multivariate analysis demonstrated that the CS pattern had the only significant independent association with DFS (P = .007) and OS (P = .037) rates. Conclusion The CS pattern as revealed at MR imaging during NAC had the only significant independent association with prognosis in patients with low-grade luminal breast cancer. © RSNA, 2017.

Cystoid Macular Edema during Treatment with Paclitaxel and Bevacizumab in a Patient with Metastatic Breast Cancer: A Case Report and Literature Review.

We present a case of a metastatic breast cancer patient with cystoid macular edema (CME) occurring during treatment with paclitaxel and bevacizumab. She had a history of neoadjuvant chemotherapy and partial mastectomy plus axillary lymph node dissection for stage IIB left-breast cancer. Twenty-four months later, she was diagnosed with multiple bone metastases and underwent chemotherapy with paclitaxel and bevacizumab. Thirty-three months after the initiation of the chemotherapy, she noticed bilateral blurred vision. The retinal thickening with macular edema was observed by optical coherence tomography, resulting in a diagnosis of CME. With cessation of paclitaxel and administrating ocular instillation of a nonsteroidal anti-inflammatory drug, her macular edema gradually reduced and disappeared in a month. While CME caused by chemotherapy is very rare, taxane may cause ocular adverse events such as CME. It is important to urge patients to consult an ophthalmologist promptly when they have visual complaints during taxane chemotherapy.

A Case of Recurrent Breast Cancer Identified by Pulmonary Tumor Thrombotic Microangiopathy.

Pulmonary tumor thrombotic microangiopathy (PTTM) is a rare, cancer-related, pulmonary complication that causes hypoxia and pulmonary hypertension. We report on a 42-year-old woman who was diagnosed with recurrent breast cancer that was detected due to the presence of PTTM. Eleven months after surgery for heterochronous bilateral cancer of the left breast, she developed progressive dyspnea but computerized tomography showed no pulmonary thromboembolism, and a transthoracic echocardiography revealed mild pulmonary hypertension. She was diagnosed with PTTM by cytology from pulmonary artery catheterization and perfusion lung scintigraphy. Also, the patients complained of back pain after admission, bone scintigraphy showed multiple bone metastases. Despite the early diagnosis of PTTM, her platelet count decreased, her performance status rapidly deteriorated, and her dyspnea worsened. Thus, we could not treat her with chemotherapy. She died due to respiratory failure 19 days after admission. To the best of our knowledge, this is the first report of recurrent breast cancer identified by the manifestation of PTTM. Although PTTM is a rare phenomenon, it should be considered in the differential diagnosis of acute dyspnea or pulmonary hypertension in patients with breast cancer. Furthermore, upon diagnosis, the patient should be referred to a cardiologist as soon as possible.

The early onset of peripheral neuropathy might be a robust predictor for time to treatment failure in patients with metastatic breast cancer receiving chemotherapy containing paclitaxel.

BACKGROUND: Paclitaxel plays a central role in chemotherapy for breast cancer. Peripheral neuropathy, a well-known toxicity with paclitaxel, may be of interest in predicting the efficacy of paclitaxel therapy for patients with metastatic breast cancer. We performed a retrospective analysis assessing whether the early occurrence of peripheral neuropathy (EPN) was a predictive marker for better efficacy in patients with metastatic breast cancer receiving chemotherapy containing paclitaxel. PATIENTS AND METHODS: Between January 2000 and August 2008, we examined the records of 168 patients with metastatic breast cancer treated with paclitaxel in our hospital. EPN was defined as a symptom of Grade 2 or more during first three months of treatment. The overall response rate (ORR) and time to treatment failure (TTF) in each group were analyzed retrospectively. RESULTS: Of 168 patients with metastatic breast cancer who were treated with paclitaxel, EPN was documented in 101 patients (60.1%). The clinical benefit rate (CR, PR, and SD ≥ 6 months) was 72.3% in the EPN group and 49.3% in the non-EPN group (p = 0.002). The TTF of the EPN group (median 11.2 months, 95% CI: 9.5-12.9) was significantly longer than that of the non-EPN group (5.7 months, 95% CI: 4.6-6.8) (p<0.001). Multivariate analysis demonstrated that EPN (p<0.001), dose intensity of less than 70% (p<0.001), and the history of microtubule agents (p = 0.001) were the significant favorable prognostic factors for TTF. CONCLUSION: The early onset of peripheral neuropathy might be a robust predictor for TTF in patients with metastatic breast cancer treated with paclitaxel.

First report of eribulin in combination with pertuzumab and trastuzumab for advanced HER2-positive breast cancer.

BACKGROUND: The efficacy and safety of continuing multiple anti-HER2 therapies in advanced breast cancer (ABC) patients remains unclear. This study investigated eribulin in combination with pertuzumab and trastuzumab for both taxane- and trastuzumab-pretreated HER2-positive ABC patients. METHODS: In a single-institute, single-arm, open-label, phase II trial, HER2-positive ABC patients who had previously received taxanes and trastuzumab were treated with eribulin in combination with pertuzumab and trastuzumab. The pharmacokinetics of eribulin in this combination were assessed in 6 patients. Tumor assessments were conducted every 6 weeks for the first 6 cycles and every 12 weeks thereafter. The primary endpoint was objective response rate (ORR). RESULTS: A total of 30 patients (median age, 58 years; range, 31-76) were enrolled, with a median number of previous chemotherapy regimens of 3.5 (range: 1-9) in the metastatic setting. Pharmacokinetic parameters of eribulin in this combination were similar to previous reports of eribulin monotherapy. ORR was 34.8% (95% CI: 16.4-57.3, n = 23), and median progression-free survival was 42.6 weeks (95% CI: 20.3-51.9, n = 30). Clinical benefit rate was 60.9% (95% CI: 16.4-57.3). The most common grade 3/4 adverse event was neutropenia in 20 patients (66.7%). A dose reduction of eribulin was required in 27 patients due to adverse events, particularly grade 3 neutropenia. CONCLUSIONS: Eribulin in combination with pertuzumab and trastuzumab was well tolerated in heavily pretreated patients. Eribulin may be a viable treatment option when used in combination with pertuzumab and trastuzumab for HER2-positive ABC patients (UMIN Clinical Trial Registry identification number, UMIN000012375).

Imatinib could be a new strategy for pulmonary hypertension caused by pulmonary tumor thrombotic microangiopathy in metastatic breast cancer.

INTRODUCTION: Pulmonary tumor thrombotic microangiopathy (PTTM) is rare, cancer-related pulmonary complication leading to hypoxia, pulmonary hypertension, and heart failure. The standard treatment for PTTM is not established. However, imatinib, a tyrosine kinase inhibitor of the PDGF receptor, may cause regression of pulmonary hypertension and pulmonary artery remodeling in PTTM. CASE DESCRIPTIONS: We report two cases of PTTM who received an anti-PDGF agent of imatinib for PTTM developed during chemotherapy for metastatic breast cancer. Case 1: 61-year-old woman who underwent resection of the left breast and axillary lymph node dissection and received adjuvant chemotherapy (CAF followed by docetaxel), then endocrine therapy for 5 years. Twelve years after surgery, multiple bone and mediastinal lymph node metastases occurred. She was under treatment with eribulin for one year but admitted because of rapid progressing dyspnea. Case 2: 45-year-old woman with metastatic breast cancer in multiple bones was under treatment for 5 years. Receiving capecitabine, she suffered from dyspnea for 2 months, she was admitted to our hospital with diagnosis of severe hypoxia. In both cases, the wedged pulmonary arterial blood cell sampling revealed cytologically malignant cells which confirmed the diagnosis of PTTM. They were treated with imatinib, which alleviated pulmonary hypertension. However, they died due to progression of metastatic breast cancer. DISCUSSION AND EVALUATION: Single use of imatinib did not showed sufficient efficacy. It is necessary to conduct a well-designed clinical trial using chemotherapies combined with imatinib for PTTM. CONCLUSIONS: Imatinib, which alleviated pulmonary hypertension, could be a new strategy for pulmonary tumor thrombotic microangiopathy in patient with metastatic breast cancer.

Predictive Factors and Value of ypN+ after Neoadjuvant Chemotherapy in Clinically Lymph Node-Negative Breast Cancer.

BACKGROUND: Pathological complete response (pCR) with neoadjuvant chemotherapy (NAC) has been regarded as a surrogate endpoint for disease-free survival (DFS) and overall survival (OS) of patients with breast cancer. No consensus regarding the definition of pCR has been established; there are several definitions according to a variety of classifications. Eradication of cancer cells in both breast and lymph nodes has been better associated with improved prognosis than in the breast alone. Even in patients diagnosed as having clinically node-negative cancer before NAC, postoperative pathological examination often shows axillary lymph node metastases. PATIENTS AND METHODS: Of the 771 patients with breast cancer who underwent NAC in the Cancer Institute Hospital between January 2000 and May 2009, 146 patients preoperatively diagnosed as having node-negative breast cancer were retrospectively evaluated. We have made the definition of clinically lymph node-negative (N0) as follows: first, ultrasonography before NAC did not show any lymphadenopathy. Second, a cytological procedure confirmed negative study for each patient when ultrasonography suggested lymphadenopathy. RESULTS: The median observation period was 79.7 months, and the median age of the subjects was 51 years. Pathological examination at the time of the surgery showed lymph node metastases (ypN+) in 46 patients (31.5%). Histological therapeutic effects revealed ypT0/is in 9 patients (6.2%) and ypTinv in 137 (93.8%). Multivariate analysis demonstrated that younger age (49>), large tumor size, NG3, and ypN+ were significant poor prognostic factors for DFS (p = 0.020, p = 0.008, P = 0.022 and p = 0.010, respectively). Moreover, ypN+ was the only significant poor prognostic factor for OS (p = 0.022). The predictive factors of ypN+ in clinically lymph node-negative breast cancer were ypTinv (p = 0.036) and the luminal type (HR+ and HER2-) (p = 0.029). CONCLUSION: The prognosis of clinically lymph node negative breast cancer depended on ypN+, which was associated with ypTinv and luminal subtype.

Eribulin-induced liver dysfunction as a prognostic indicator of survival of metastatic breast cancer patients: a retrospective study.

BACKGROUND: Eribulin is a non-taxane, microtubule dynamics inhibitor that increases survival of patients with metastatic breast cancer. Although eribulin is well tolerated in patients with heavily pretreated disease, eribulin-induced liver dysfunction (EILD) can occur, resulting in treatment modification and subsequent poor disease control. We aimed to clarify the effect of EILD on patient survival. METHODS: The medical records of 157 metastatic breast cancer patients treated with eribulin between July 2011 and November 2013 at Cancer Institute Hospital were retrospectively analyzed. EILD was defined as 1) an increase in alanine aminotransferase or aspartate aminotransferase levels >3 times the upper limit of normal, and/or 2) initiation of a liver-supporting oral drug therapy such as ursodeoxycholic acid or glycyron. Fatty liver was defined as a decrease in the liver-to-spleen attenuation ratio to <0.9 on a computed tomography scan. RESULTS: EILD occurred in 42 patients, including one patient for whom eribulin treatment was discontinued due to severe EILD. The patients who developed EILD had significantly higher body mass indices (BMIs) than those who did not develop EILD (24.5 vs. 21.5, respectively; P < 0.0001), with no difference in the dose intensity of eribulin between the two groups (P = 0.76). Interestingly, the patients with EILD exhibited significantly longer progression-free survival (PFS) and overall survival (OS) than those without EILD (P = 0.010 and P = 0.032, respectively). Similarly, among 80 patients without liver metastasis, 19 with EILD exhibited significantly longer PFS and OS than the others (P = 0.0012 and P = 0.044, respectively), and EILD was an independent prognostic factor of PFS (P = 0.0079) in multivariate analysis. During eribulin treatment, 18 patients developed fatty liver, 11 of whom developed EILD, with a median BMI of 26.7. CONCLUSIONS: Although EILD and fatty liver occurred at a relatively high frequency in our study, most of the patients did not experience severe adverse effects. Surprisingly, the development of EILD was positively associated with patient survival, especially in patients without liver metastases. EILD may be a clinically useful predictive biomarker of survival, but further studies are needed to confirm these findings in another cohort of patients.