An Exploratory Phase II Study of Eribulin Re-challenge After Short Term Therapy of 5-Fluorouracil for HER2 Negative, Advanced or Recurrent Breast Cancer.

BACKGROUND/AIM: In our previous study, first-line eribulin (ERI) showed 25 weeks of progression-free survival (PFS). This study investigated the efficacy and safety of ERI re-administration in metastatic breast cancer (MBC) patients. PATIENTS AND METHODS: HER2-negative MBC patients who had never received chemotherapy for MBC received first-line ERI for 18 weeks if they did not have disease progression, and then one cycle of S-1 before ERI re-administration. RESULTS: Twelve patients received ERI re-administration. The PFS of re-administered ERI was 13 weeks. Total duration of ERI use was 30 weeks. The incidence and severity of adverse events were consistent with previous reports. CONCLUSION: In the first-line setting, the total PFS of eribulin was extended by S-1 administration before disease progression, compared with that of our previous report.

Exchange of Proteins in Liposomes through Streptolysin O Pores.

Liposomes, which are vesicles surrounded by lipid membranes, can be used as biochemical reactors by encapsulating various reactions. Accordingly, they are useful for studying cellular functions under controlled conditions that mimic the environment within a cell. However, one of the shortcomings of liposomes as biochemical reactors is the difficulty of introducing or removing proteins due to the impermeability of the membrane. In this study, we established a method for exchanging proteins in liposomes by forming reversible pores in the membrane. We used the toxic protein streptolysin O (SLO); this forms pores in membranes made of phospholipids containing cholesterol that can be closed by the addition of calcium ions. After optimizing the experimental procedure and lipid composition, we observed the exchange of fluorescent proteins (transferrin Alexa Fluor 488 and 647) in 9.9 % of liposomes. We also introduced T7 RNA polymerase, a 98-kDa enzyme, and observed RNA synthesis in ∼8 % of liposomes. Our findings establish a new method for controlling the internal protein composition of liposomes, thereby increasing their utility as bioreactors.

[Radiation-Induced Undifferentiated Pleomorphic Sarcoma after Breast-Conserving Surgery-A Case Report].

The patient was a 73-year-old woman who had undergone breast-conserving surgery followed by irradiation (50 Gy/25 Fr)to the residual breast for left breast cancer 4 years before. Computed tomography for routine examination revealed a soft tissue mass on her left chest wall. Ultrasonography showed a hypoechoic mass with heterogeneous internal echo, 3.5×3.0×1.5 cm in size. Core-needle biopsy was performed, and histological examination revealed proliferation of spindle-shaped or pleomorphic and highly atypical cells. On immunohistochemistry, the tumor was negative for AE1/AE3, CD34, SMA, desmin, and S-100 and focally positive for CD68. Based on these findings, undifferentiated sarcoma was suspected. The patient underwent wide local excision of the chest wall with a surgical margin of 3-4 cm from the tumor edge. The histological diagnosis was undifferentiated pleomorphic sarcoma. Judging from the clinical course, this tumor was radiation-induced sarcoma. The patient remains disease-free 54 months after the operation.

[A Case of Effective Endovascular Treatment for Recurrent Bleeding from Advanced Breast Cancer].

A-58-year-old woman was diagnosed with breast cancer 8 years ago at another hospital, but refused surgical treatment. From 2 years ago, her skin invasion of cancer lesions began bleeding. The patient required frequent blood transfusions due to anemia associated with repeated bleeding. She was referred to our department for local treatment and palliative care. Diagnostic imaging revealed multiple lung, bone and liver metastasis. The patient refused to receive systemic chemotherapy, and she was recommended radiation therapy for repeated massive bleeding, but her consent was not obtained. She agreed to receive arterial embolization from the tumor-bearing vessels plus intravenous anti-cancer drug therapy. The hemostatic effect was observed for 4 to 5 weeks per treatment, and tumor reduction was also observed. She received a total of 6 treatments during 8 months until her death. These treatments were effective in maintaining quality of life at the end of life.

Neoadjuvant Chemotherapy With Nab-paclitaxel Plus Trastuzumab Followed by 5-Fluorouracil/Epirubicin/Cyclophosphamide for HER2-positive Operable Breast Cancer: A Multicenter Phase II Trial.

AIM: This study was conducted in order to evaluate the efficacy and safety of nanoparticle albumin-bound paclitaxel (nab-paclitaxel) plus trastuzumab followed by 5-fluorouracil/ epirubicin/cyclophosphamide (FEC) in a neoadjuvant chemotherapy (NAC) setting for patients with human epidermal growth factor receptor 2 (HER2)-positive operable breast cancer. PATIENTS AND METHODS: Each patient received four cycles of 260 mg/m2 nab-paclitaxel with 6 mg/kg trastuzumab (8 mg/kg as the loading dose) every 3 weeks (q3w) followed by four cycles of FEC (500/100/500 mg/m2) q3w. The primary endpoint was pathological complete response (pCR) rate. RESULTS: Twenty-nine patients were analyzed for the efficacy and safety of this treatment. All patients completed four cycles of nab-paclitaxel and trastuzumab, and 28 patients completed four cycles of FEC. Twenty-seven patients subsequently underwent surgery. The pCR rate was 74.0%. The most frequent toxicity was sensory neuropathy (96.6%), but grade 3 neuropathy rate was 3.4%. CONCLUSION: Nab-paclitaxel plus trastuzumab followed by FEC in patients with HER2-positive operable breast cancer is considerably effective and well tolerated.

Breast metastasis from EGFR-mutated lung adenocarcinoma: A case report and review of the literature.

Although lung cancer rarely metastasizes to the breast, we report a case of breast metastasis from lung adenocarcinoma harboring an epidermal growth factor receptor mutation. This breast metastasis was initially considered recurrent breast cancer and was later diagnosed based on histopathological and molecular examinations as metastasis from lung cancer.

Production of giant unilamellar vesicles by the water-in-oil emulsion-transfer method without high internal concentrations of sugars.

Giant unilamellar vesicles (GUVs) are large vesicles bounded by a single lipid bilayer, which have been used in various applications as artificial, cell-like compartments. The water-in-oil (w/o) emulsion-transfer method has been attracting attention as a method to prepare GUVs that can efficiently encapsulate macromolecules. For efficient GUV production by this method, non-physiological, high concentrations of sugars are usually required in the inner solution of the GUVs. These sugars limit the utility of the GUVs for a wide range of applications. In this study, we investigated various compositions of the inner and outer solutions to achieve efficient production without high concentrations of sugars through the w/o emulsion-transfer method. Firstly, we adjusted the osmotic pressure and density of the outer solution with NaCl and succeeded in increasing the proportion of GUVs and the absolute number in the prepared liposome population. Secondly, we increased the density of the inner solution with cytochrome c, but the proportion of GUVs and absolute number of vesicles did not increase. Thirdly, we increased the density of the inner and outer solutions with glycerol, which is membrane permeable and can be removed from GUVs, and succeeded in increasing the GUV proportion. These results provide useful information for the efficient preparation of GUVs that enclose a physiologically-relevant environment by the w/o emulsion-transfer method.

Safety and Efficacy of Low-dose Nanoparticle Albumin-bound Paclitaxel for HER2-negative Metastatic Breast Cancer.

BACKGROUND/AIM: Nab-paclitaxel (nab-PTX) is an albumin-bound paclitaxel formulation. Although nab-PTX has shown superior efficacy compared to conventional paclitaxel (PTX) in metastatic breast cancer (MBC), chemotherapy-induced peripheral neuropathy (CIPN) was more frequently observed in nab-PTX. In this study, we aimed to estimate the feasibility of the nab-PTX 175 mg/m2/3weeks regimen. PATIENTS AND METHODS: Patients having metastatic or inoperable HER2-negative breast cancer received 175 mg/m2 of nab-PTX every three weeks. The primary endpoint was safety and the secondary endpoints were response and survival. RESULTS: Seventeen patients were enrolled with a median age of 64 years. Ten patients had estrogen receptor positive disease and seven had triple-negative disease. CIPN was observed in seven patients (41%) however, grade 3 CIPN was only seen in one patient (6%). Objective response rate was 41% and progression-free survival was 23 weeks. CONCLUSION: Nab-PTX 175 mg/m2/3wks regimen has a good safety profile and less frequent CIPN. This regimen can contribute to the strategy of MBC treatment.

In Vitro Evolution of Unmodified 16S rRNA for Simple Ribosome Reconstitution.

One of the largest challenges in the synthesis of artificial cells that can reproduce is in vitro assembly of ribosomes from in vitro synthesized rRNAs and proteins. In this study, to circumvent the post-transcriptional modification of 16S rRNA for reconstitution of the fully active 30S subunit, we performed artificial evolution of 16S rRNA, which forms the functional 30S subunit without post-transcriptional modifications. We first established an in vitro selection scheme by combining the integrated synthesis, assembly, and translation (iSAT) system with the liposome sorting technique. After 15 rounds of selection cycles, we found one point mutation (U1495C) near the 3' terminus that significantly enhanced the reconstitution activity of the functional 30S subunit from unmodified 16S rRNA to approximately 57% of that from native-modified 16S rRNA. The effect of the mutation did not depend on the reconstitution scheme, anti-SD sequences, or the target genes to be translated. The mutation we found in this study enabled reconstitution of the active 30S subunit without rRNA modification, and thus would be a useful tool for simple construction of self-reproducing ribosomes.

Flow Cytometric Analysis To Evaluate Morphological Changes in Giant Liposomes As Observed in Electrofusion Experiments.

Liposome fusion is a way of supplying additional components for in-liposome biochemical reactions. Electrofusion is a method that does not require the addition of fusogens, which often alter the liposome dispersion, and is therefore useful for repetitive liposome fusion. However, the details of electrofusion have not been elucidated because of the limitations surrounding observing liposomes using a microscope. Therefore, we introduced fluorescent markers and high-throughput flow cytometry to analyze the morphological changes that occur in liposome electrofusion. (i) The content mixing was evaluated by a calcein-Co2+-EDTA system, in which green fluorescence from dequenched free calcein is detected when the quenched calcein-Co2+ complex and EDTA are mixed together. (ii) Liposome destruction was evaluated from the decrease in the total membrane volume of giant liposomes. (iii) Liposome fission was evaluated from the increase in the number of giant liposomes. By applying the flow cytometric analysis, we investigated the effect of three parameters (DC pulse, AC field, and lipid composition) on liposome electrofusion. The larger numbers or higher voltages of DC pulses induced liposome fusion and destruction with higher probability. The longer application time of the AC field induced liposome fusion, fission, and destruction with higher probability. Higher content of negatively charged POPG (≥19%) strongly inhibited liposome electrofusion.

Phase I study of nanoparticle albumin-bound paclitaxel, carboplatin and trastuzumab in women with human epidermal growth factor receptor 2-overexpressing breast cancer.

Although the concurrent use of anthracycline-containing chemotherapy and taxane with trastuzumab are considered the treatment of choice for the primary systemic therapy of human epidermal growth factor receptor 2 (HER2)-overexpressing early breast cancer, non-anthracycline regimens, such as concurrent administration of docetaxel and carboplatin with trastuzumab, exhibited similar efficacies in a previous study. In addition, tri-weekly treatment with nanoparticle albumin-bound paclitaxel (nab-paclitaxel) resulted in significantly higher response rates and a favorable safety profile compared with standard paclitaxel for metastatic breast cancer patients in another phase III study. Based on these results, a phase I study of combination therapy with nab-paclitaxel, carboplatin and trastuzumab was planned, in order to estimate its efficacy and safety for HER2-overexpressing locally advanced breast cancer. The present study was designed to determine the dose-limiting toxicity (DLT), maximum tolerated dose and recommended dose of this combination treatment in women with HER2-overexpressing locally advanced breast cancer. The starting dose of nab-paclitaxel was 220 mg/m2 (level 1), and the dose was escalated to 260 mg/m2 (level 2). Nab-paclitaxel was administered with carboplatin (area under the curve, 6 mg/ml/min) and trastuzumab tri-weekly. A total of 6 patients were enrolled. Although no DLT was observed during the first cycle, 4 patients developed grade 4 thrombocytopenia, 2 had grade 4 neutropenia and 3 exhibited a grade 4 decrease in hemoglobin levels. In the present phase I study, although no patients experienced DLTs, this regimen was associated with severe hematological toxicities and it was not well tolerated. However, considering the high efficacy and lower risk of cardiotoxicity and secondary carcinogenesis with taxane, platinum and trastuzumab combination therapy, further evaluation of another regimen including weekly administration or a more accurate dose setting should be conducted.

Effect of Liposome Size on Internal RNA Replication Coupled with Replicase Translation.

Cell membranes inhibit the diffusion of intracellular materials, and compartment size can strongly affect the intracellular biochemical reactions. To assess the effect of the size of microcompartments on intracellular reactions, we constructed a primitive cell model consisting of giant liposomes and a translation-coupled RNA replication (TcRR) system. The RNA was replicated by Qß replicase, which was translated from the RNA in giant liposomes encapsulating the cell-free translation system. A reporter RNA encoding the antisense strand of ß-glucuronidase was introduced into the system to yield a TcRR read-out (green fluorescence). We demonstrate that TcRR was hardly detectable in larger liposomes (230 fL) but was more effective in smaller (7.7 fL) liposomes. Our experimental and theoretical results show that smaller microcompartments considerably enhance TcRR because the synthesized molecules, such as RNA and replicases, are more concentrated in smaller liposomes.

A phase II, multicenter, single-arm trial of eribulin as first-line chemotherapy for HER2-negative locally advanced or metastatic breast cancer.

The treatment goals for metastatic breast cancer (MBC) are prolonging survival and improving the quality of life. Eribulin, a non-taxane tubulin inhibitor, demonstrated improved survival in previous studies and also showed mild toxicity when used in late-line therapy for MBC. We conducted a phase II study to investigate the efficacy of eribulin mesylate as the first-line chemotherapy for human epidermal growth factor receptor 2 (HER2)-negative MBC. This was a phase II, open-label, single-arm, multicenter trial conducted in Japan. Patients with HER2-negative MBC received intravenous eribulin (1.4 mg/m(2) on days 1 and 8 of each 21-day cycle). The primary efficacy outcome was overall response rate (ORR). Secondary outcomes included time to treatment failure, progression-free survival (PFS), overall survival (OS), and safety. A total of 35 patients were enrolled and received a median of 8 (range 1-21) cycles of eribulin therapy. ORR and clinical benefit rate were 54.3 and 62.9 %, respectively. Median PFS was 5.8 months and median OS was 35.9 months. Grade 3 or 4 neutropenia was observed in 63 % of patients. The majority of non-hematological adverse events were mild in severity. The present trial demonstrated that eribulin has antitumor activity comparable with other key established cytotoxic agents with acceptable safety and tolerability. Thus, eribulin as first-line chemotherapy might be beneficial for patients with HER2-negative MBC.

Sustainable proliferation of liposomes compatible with inner RNA replication.

Although challenging, the construction of a life-like compartment via a bottom-up approach can increase our understanding of life and protocells. The sustainable replication of genome information and the proliferation of phospholipid vesicles are requisites for reconstituting cell growth. However, although the replication of DNA or RNA has been developed in phospholipid vesicles, the sustainable proliferation of phospholipid vesicles has remained difficult to achieve. Here, we demonstrate the sustainable proliferation of liposomes that replicate RNA within them. Nutrients for RNA replication and membranes for liposome proliferation were combined by using a modified freeze-thaw technique. These liposomes showed fusion and fission compatible with RNA replication and distribution to daughter liposomes. The RNAs in daughter liposomes were repeatedly used as templates in the next RNA replication and were distributed to granddaughter liposomes. Liposome proliferation was achieved by 10 cycles of iterative culture operation. Therefore, we propose the use of culturable liposomes as an advanced protocell model with the implication that the concurrent supplement of both the membrane material and the nutrients of inner reactions might have enabled protocells to grow sustainably.

The evolutionary enhancement of genotype-phenotype linkages in the presence of multiple copies of genetic material.

Genetic evolutionary mechanisms employed by protolife developed without accompanying regulatory mechanisms for the amounts of genetic material in protocells. When many copies of genetic material are present, inactive copies generated by mutations are not effectively excluded through phenotypic selection. We demonstrate a model of gene evolution initiated with different amounts of DNA inside artificial protocells. We adopted transcription- and translation-coupled RNA replication and liposome-based in vitro compartmentalization. Despite the fact that the average number of DNA copies in each liposome was 6.4, DNA encoding active genes was maintained until the 16th selection round. Our experimental and theoretical results indicated that gene evolution can occur in the presence of multiple DNA copies. Most genetic material became junk code through gene mutations, and consequently the linkage between genotype and phenotype was enhanced through the associated decreases in active genetic material.

[A case of S-1/CDDP-resistant recurrent gastric cancer responsive to capecitabine/CDDP].

We present a case of recurrent gastric cancer in which stable disease status was achieved for four months due to treatment with capecitabine/cisplatin (CDDP)after the failure of multiple anticancer drugs including S-1/CDDP. A 67-year-old man was diagnosed with multiple liver metastases one year after distal gastrectomy+D2 dissection for gastric cancer. S-1/CDDP was given as the first-line treatment, followed by paclitaxel (PTX), irinotecan (CPT-11), and docetaxel (DOC). The tumor in the anterior segment of the liver was resistant to all of these chemotherapies except for PTX, which is why the regimens were changed. However, this tumor shrank and achieved stable disease status for four months after capecitabine/CDDP therapy given as fifth-line treatment. Our case suggests that S-1 and capecitabine do not always exhibit cross-resistance. Therefore, capecitabine may be effective in S-1-pretreated patients, and vice versa.

Liposome display for in vitro selection and evolution of membrane proteins.

Liposome display is a novel method for in vitro selection and directed evolution of membrane proteins. In this approach, membrane proteins of interest are displayed on liposome membranes through translation from a single DNA molecule by using an encapsulated cell-free translation system. The liposomes are probed with a fluorescence indicator that senses membrane protein activity and selected using a fluorescence-activated cell sorting (FACS) instrument. Consequently, DNA encoding a protein with a desired function can be obtained. By implementing this protocol, researchers can process a DNA library of 10(7) different mutants. A single round of the selection procedure requires 24 h for completion, and multiple iterations of this technique, which take 1-5 weeks, enable the isolation of a desired gene. As this protocol is conducted entirely in vitro, it enables the engineering of various proteins, including pore-forming proteins, transporters and receptors. As a useful example of the approach, here we detail a procedure for the in vitro evolution of α-hemolysin from Staphylococcus aureus for its pore-forming activity.

Darwinian evolution in a translation-coupled RNA replication system within a cell-like compartment.

The ability to evolve is a key characteristic that distinguishes living things from non-living chemical compounds. The construction of an evolvable cell-like system entirely from non-living molecules has been a major challenge. Here we construct an evolvable artificial cell model from an assembly of biochemical molecules. The artificial cell model contains artificial genomic RNA that replicates through the translation of its encoded RNA replicase. We perform a long-term (600-generation) replication experiment using this system, in which mutations are spontaneously introduced into the RNA by replication error, and highly replicable mutants dominate the population according to Darwinian principles. During evolution, the genomic RNA gradually reinforces its interaction with the translated replicase, thereby acquiring competitiveness against selfish (parasitic) RNAs. This study provides the first experimental evidence that replicating systems can be developed through Darwinian evolution in a cell-like compartment, even in the presence of parasitic replicators.

In vitro evolution of α-hemolysin using a liposome display.

In vitro methods have enabled the rapid and efficient evolution of proteins and successful generation of novel and highly functional proteins. However, the available methods consider only globular proteins (e.g., antibodies, enzymes) and not membrane proteins despite the biological and pharmaceutical importance of the latter. In this study, we report the development of a method called liposome display that can evolve the properties of membrane proteins entirely in vitro. This method, which involves in vitro protein synthesis inside liposomes, which are cell-sized phospholipid vesicles, was applied to the pore-forming activity of α-hemolysin, a membrane protein derived from Staphylococcus aureus. The obtained α-hemolysin mutant possessed only two point mutations but exhibited a 30-fold increase in its pore-forming activity compared with the WT. Given the ability to synthesize various membrane proteins and modify protein synthesis and functional screening conditions, this method will allow for the rapid and efficient evolution of a wide range of membrane proteins.

Directed Evolution of Proteins through In Vitro Protein Synthesis in Liposomes.

Directed evolution of proteins is a technique used to modify protein functions through "Darwinian selection." In vitro compartmentalization (IVC) is an in vitro gene screening system for directed evolution of proteins. IVC establishes the link between genetic information (genotype) and the protein translated from the information (phenotype), which is essential for all directed evolution methods, by encapsulating both in a nonliving microcompartment. Herein, we introduce a new liposome-based IVC system consisting of a liposome, the protein synthesis using recombinant elements (PURE) system and a fluorescence-activated cell sorter (FACS) used as a microcompartment, in vitro protein synthesis system, and high-throughput screen, respectively. Liposome-based IVC is characterized by in vitro protein synthesis from a single copy of a gene in a cell-sized unilamellar liposome and quantitative functional evaluation of the synthesized proteins. Examples of liposome-based IVC for screening proteins such as GFP and ß-glucuronidase are described. We discuss the future directions for this method and its applications.