The Importance of Suppressing Pathological Periostin Splicing Variants with Exon 17 in Both Stroma and Cancer.

BACKGROUND: Periostin (POSTN) is a type of matrix protein that functions by binding to other matrix proteins, cell surface receptors, or other molecules, such as cytokines and proteases. POSTN has four major splicing variants (PN1-4), which are primarily expressed in fibroblasts and cancer. We have reported that we should inhibit pathological POSTN (PN1-3), but not physiological POSTN (PN4). In particular, pathological POSTN with exon 17 is present in both stroma and cancer, but it is unclear whether the stroma or cancer pathological POSTN should be suppressed. METHODS AND RESULTS: We transplanted 4T1 cells (breast cancer) secreting POSTN with exon 17 into 17KO mice lacking POSTN exon 17 to suppress stromal POSTN with exon 17. The results show that 17KO mice had smaller primary tumors and fewer metastases. Furthermore, to suppress cancer POSTN with exon 17, 4T1 cells transfected with POSTN exon 17 skipping oligo or control oligo were transplanted from the tail vein into the lungs. The results show that POSTN exon 17 skipping oligo significantly suppressed lung metastasis. CONCLUSIONS: These findings suggest that it is important to suppress POSTN exon 17 in both stroma and cancer. Antibody targeting POSTN exon 17 may be a therapeutic candidate for breast cancer.

Expression of Periostin Alternative Splicing Variants in Normal Tissue and Breast Cancer.

(1) Background: Periostin (Pn) is a secreted protein found in the extracellular matrix, and it plays a variety of roles in the human body. Physiologically, Pn has a variety of functions, including bone formation and wound healing. However, it has been implicated in the pathogenesis of various malignant tumors and chronic inflammatory diseases. Pn has alternative splicing variants (ASVs), and our previous research revealed that aberrant ASVs contribute to the pathogenesis of breast cancer and heart failure. However, the difference in expression pattern between physiologically expressed Pn-ASVs and those expressed during pathogenesis is not clear. (2) Methods and results: We examined normal and breast cancer tissues, focusing on the Pn-ASVs expression pattern to assess the significance of pathologically expressed Pn-ASVs as potential diagnostic and therapeutic targets. We found that most physiologically expressed Pn isoforms lacked exon 17 and 21. Next, we used human breast cancer and normal adjacent tissue (NAT) to investigate the expression pattern of Pn-ASVs under pathological conditions. Pn-ASVs with exon 21 were significantly increased in tumor tissues compared with NAT. In situ hybridization identified the synthesis of Pn-ASVs with exon 21 in peri-tumoral stromal cells. Additionally, the in vivo bio-distribution of 89Zr-labeled Pn antibody against exon 21 (Pn-21Ab) in mice bearing breast cancer demonstrated selective and specific accumulation in tumors, while Pn-21Ab significantly suppressed tumor growth in the mouse breast cancer model. (3) Conclusions: Together, these data indicate that Pn-ASVs might have potential for use as diagnostic and therapeutic targets for breast cancer.

Periostin Exon-21 Antibody Neutralization of Triple-Negative Breast Cancer Cell-Derived Periostin Regulates Tumor-Associated Macrophage Polarization and Angiogenesis.

Periostin (Pn) is involved in multiple processes of cancer progression. Previously, we reported that Pn expression is correlated with mesenchymal tumor markers and poor prognosis in triple-negative breast cancer (TNBC). In the TNBC xenograft model, chemotherapy increased expression of a Pn alternative splicing variant (ASV) with exon 21, and administration of the neutralizing antibody against Pn with exon 21 (Pn-21 Ab) overcame chemoresistance with a reduction in the mesenchymal cancer cell fraction. In the present study, the role of Pn ASV with exon 21 in TNBC progression has been addressed. We first established a stable cell line carrying a fluorescence-based splicing reporter. Pn-positive TNBC has higher expression of genes related to tumor-associated macrophage (TAM) recruitment and ECM-receptor interaction than Pn-negative cells. In a xenograft model, only Pn-positive cells initiated tumor formation, and the Pn-21 Ab suppressed tumor cell growth, accompanied by decreased M2 TAM polarization and the number of tumor vessels. These data suggest that cancer cell-derived Pn ASV educates TAMs and regulates angiogenesis, which in turn establishes a microenvironmental niche that is supportive of TNBC.

Frequency and Severity of Adverse Drug Events by Medication Classes: The JADE Study.

OBJECTIVE: Adverse drug events (ADEs) are a significant concern in daily practice; however, the profile of high-risk drugs remains unclear. Our objective was to categorize high-risk medication classes according to frequency and severity of ADEs. METHODS: The JADE study is a prospective cohort study of 3459 hospitalized adult patients. We investigated the ADEs and medications prescribed to the patients. The rate of ADEs for each medication class was calculated by dividing the number of ADEs by the number of patients who received each medication class on admission. RESULTS: Overall, 14,435 medications were ordered on admission for patients (median 4; interquartile range, 2-6). Electrolytes and fluids were most frequently prescribed (1876 patients, 54%). Sedatives, antibiotics, peptic ulcer drugs, and analgesics were also commonly prescribed. The frequency was similar in both elderly and younger patients. Among 1010 identified ADEs, antibiotics were most frequently associated with ADEs (31 ADEs per 100 prescribed patients on admission). In patients 65 years and older, corticosteroids, anticonvulsants, laxatives, nonsteroidal anti-inflammatory drugs, and antipsychotics were the 5 most frequent medication classes causing ADEs following antibiotics. In patients younger than 65 years, antibiotics were also the most frequent cause of ADEs, followed by laxatives, lipid-lowering agents, anticonvulsants, and corticosteroids. Among cardiovascular agent-associated ADEs, 46% were fatal or life threatening in elderly patients, whereas antihypertensives were most often associated with fatal or life-threatening ADEs (25%) in younger patients. CONCLUSIONS: The medication classes frequently associated with ADEs did not necessarily induce severe ADEs.