Discovery of a Highly Specific Anti-methotrexate (MTX) DNA Aptamer for Antibody-Independent MTX Detection.

High-dose methotrexate (MTX) therapy is used to treat a wide variety of cancers such as leukemia and lymphoma, while the resulting high blood concentration of MTX faces a risk of life-threatening side effects, so it is essential to monitor the concentration carefully. Currently, the MTX concentration is measured using antibody-based kits in a clinical setting; however, the heterogeneity and batch-to-batch variation of antibodies potentially compromise the detection limit. Here, we developed MTX detection systems with chemically synthesizable homogeneous oligonucleotides. Microbead-assisted capillary electrophoresis (MACE)-SELEX against MTX successfully identified MSmt7 with a similar level of specificity to anti-MTX antibodies within three rounds. The 3'-end of MSmt7 was coupled to a peroxidase-like hemin-DNAzyme to construct a bifunctional oligonucleotide for MTX sensing, where MTX in 50% human serum was detected with a limit of detection (LoD) of 118 nM. Furthermore, amplifying the DNAzyme region with rolling circle amplification significantly improved the sensitivity with an LoD of 290 pM. Presented oligonucleotide-based MTX detection systems will pave the way for antibody-independent MTX detection with reliability and less cost in the laboratory and the clinic.

[One Case of Accessory Breast Cancer Complicated by Contralateral Breast Cancer].

We experienced a case of right sided accessory breast cancer complicated by contralateral breast cancer. A 50-year-old woman came to us for an examination because a tumor in her left breast was pointed out at breast cancer screening. A breast MRI confirmed a tumor in her left breast and a tumor continuing from the skin to the subcutis of the right axilla. A skin biopsy for the tumor in the right axilla and a core needle biopsy(CNB)for the tumor in the left breast were performed. The pathological result of the CNB for the left breast indicated an invasive ductal carcinoma of the tubular formative scirrhous type. Although the tumor of the right axilla was poorly differentiated adenocarcinoma demonstrating cord-like arrays, it was examined by skin biopsy and therefore no deep part of the tissue was included. We conducted immunostaining, in consideration of the possibility of metastasis from the left sided breast cancer. ER, PgR, mammaglobin, GATA 3 were positive, strongly suggesting that the tumor in the right axilla was also derived from a mammary gland. We also performed a wide local excision of the right axilla plus axillary dissection(level Ⅰ)in addition to conducting a left mastectomy plus sentinel lymph node biopsy, in consideration of the possibility of primary right sided accessory breast cancer. The pathological result following surgery confirmed a difference in the histologic features between both sides, residual normal accessory mammary glands around the tumor on the right side, and the presence of rich DCIS and a lobular replacement image, leading to a definitive diagnosis of primary invasive ductal carcinoma of the accessory breast on the right side.

ROS-mediated synthetic growth defect caused by impaired metabolism of sphingolipids and phosphatidylserine in budding yeast.

Previously, we found that yeast exhibits a strong growth defect with the combination of a lack of gene involved in structural modification of sphingolipids and repression of the phosphatidylserine synthase gene. Here we found that the double gene mutation causes reactive oxygen species-mediated cell growth defect, which is suppressed by deletion of LEM3 encoding the subunit of phospholipid flippase.