Anti-RYR1 polyclonal antibody

In mature skeletal muscle, the intracellular Ca2+ concentration rises dramatically upon membrane depolarization, constituting the link between excitation and contraction. This process requires Ca2+ release from the sarcoplasmic reticulum via the type 1 ryanodine receptor (RYR1). However, RYR1's potential roles in muscle development remain obscure. We used an established RyR1-null mouse model, dyspedic, to investigate the effects of the absence of a functional RYR1 and, consequently, the lack of RyR1-mediated Ca2+ signaling, during embryogenesis. Homozygous dyspedic mice die after birth and display small limbs and abnormal skeletal muscle organization. Skeletal muscles from front and hind limbs of dyspedic fetuses (day E18.5) were subjected to microarray analyses, revealing 318 differentially expressed genes. We observed altered expression of multiple transcription factors and members of key signaling pathways. Differential regulation was also observed for genes encoding contractile as well as muscle-specific structural proteins. Additional qRT-PCR analysis revealed altered mRNA levels of the canonical muscle regulatory factors Six1, Six4, Pax7, MyoD, MyoG and MRF4 in mutant muscle, which is in line with the severe developmental retardation seen in dyspedic muscle histology analyses. Taken together, these findings suggest an important non-contractile role of RyR1 or RYR1-mediated Ca2+ signaling during muscle organ development.

Purpose: Platinum-based chemotherapy, consisting of etoposide and cisplatin (EP), has been the cornerstone of therapy for extensive-stage small-cell lung cancer (ES-SCLC) for decades. Despite the marked initial sensitivity of SCLC to chemotherapy, EP regimens cannot avoid the emergence of drug resistance in clinical practice. With the rise of new chemotherapy regimens in recent years and the primary resistance or insensitivity of ES-SCLC to EP regimens, it is desirable to be able to identify patients with resistant or insensitive ES-SCLC. Methods: The sequencing and drug sensitivity data of SCLC cell lines were provided by The Genomics of Drug Sensitivity in Cancer Project (GDSC). The data regarding sensitivity to etoposide of 54 SCLC cell lines were analyzed, and etoposide-sensitive cell lines and etoposide-resistant cell lines were differentiated according to the IC50 values defined by the GDSC. ROC curve analysis was performed on all mutations and combinations of mutations to select the optimal panel to predict resistance to etoposide. Results: ROC analysis of etoposide resistance revealed that the most significant single gene mutation indicating resistance to etoposide was CSMD3, and the accuracy of predicting resistance to etoposide proved to be the highest when there was any mutation in CSMD3/ PCLO/RYR1/EPB41L3, area under the curve =0.804 (95% confidence interval: 0.679-0.930, P<0.001). Conclusion: This study found that a panel with four genes (CSMD3, EPB41L3, PCLO, and RYR1) can accurately predict sensitivity to etoposide. These findings provide new insights into the overall treatment for patients with ES-SCLC that is resistant or insensitive to etoposide.