Isolation and characterization of mutations affecting expression of the Δ9- fatty acid desaturase gene, OLE1, in Saccharomyces cerevisiae

AbstractExpression of the Δ9- fatty acid desaturase gene, OLE1, of Saccharomyces cerevisiae is negatively regulated transcriptionally and post-transcriptionally by unsaturated fatty acids. In order to isolate mutants exhibiting irregulation of OLE1 expression, we constructed an OLE1p–PHO5 fusion gene as a reporter consisting of the PHO5 gene encoding repressible acid phosphatase (rAPase) under the control of the OLE1 promoter (OLE1p). By EMS mutagenesis, we isolated three classes of mutants, pfo1, pfo2 and pfo3 (positive regulatory factor for OLE1) mutants, which show decreased rAPase activity under derepression conditions (absence of oleic acid). Analysis of the transcription of OLE1 in these pfo mutants revealed that pfo1 and pfo3 mutants have a defect in the regulation of OLE1 expression at the transcriptional level while pfo2 mutants were suggested to have a mutation affecting OLE1 expression at a post-transcriptional step. In addition, four other classes of mutants, nfo1, nfo2, nfo3 and nfo4 (negative factor for OLE1) mutants that have mutations causing strong expression of the OLE1p–PHO5 fusion gene under repression conditions (presence of oleic acid), were isolated. Results of Northern analysis of OLE1 as well as OLE1p-PHO5 transcripts in nfo mutants suggested that these mutations occurred in genes encoding global repressors. We also demonstrated that TUP1 and SSN6 gene products are required for full repression of OLE1 gene expression, by showing that either tup1 or ssn6 mutations greatly increase the level of the OLE1 transcript

Clinical significance of ribosomal protein S15 expression in patients with colorectal cancer liver metastases

Sakano Y., Matoba D., Noda T., et al. Clinical significance of ribosomal protein S15 expression in patients with colorectal cancer liver metastases. Journal of Hepato-Biliary-Pancreatic Sciences, (2024); https://doi.org/10.1002/jhbp.12012.Background: Liver metastasis is the most frequently observed distant metastasis of colorectal cancer, and the residual liver recurrence rate after hepatic resection is still high. To explore the mechanism of liver metastasis to discover potential new treatments, we assessed the relationship between the expression of differentially expressed genes (DEGs) and prognosis in patients with colorectal cancer liver metastasis (CRLM). Methods: The gene expression dataset was extracted from The Cancer Genome Atlas and the Gene Expression Omnibus. Significance analysis of DEGs between tumor and normal samples of colorectum, liver, and lung was conducted. A total of 80 CRLM patients were studied to assess the expression of RPS15, characteristics, and outcomes. We examined the relationships of RPS15 expression to cell viability and apoptosis in vitro and vivo. Results: Significance analysis identified 33 DEGs. In our cohorts, the overall survival rates were significantly lower in the high-RPS15-expression group, and high expression of RPS15 was an independent and unfavorable prognostic factor in recurrence-free survival and overall survival. Knockdown of RPS15 expression reduced the proliferative capacity of colorectal cancer cells and increased BAX-induced apoptotic cell death. Conclusions: RPS15 expression is an independent prognostic factor for CRLM patients and might be a novel therapeutic target for CRLM

Difference between carbohydrate antigen 19-9 and fluorine-18 fluorodeoxyglucose positron emission tomography in evaluating the treatment efficacy of neoadjuvant treatment in patients with resectable and borderline resectable pancreatic ductal adenocarcinoma: Results of a dual-center study

kita, H, Takahashi, H, Eguchi, H, et al. Difference between carbohydrate antigen 19‐9 and fluorine‐18 fluorodeoxyglucose positron emission tomography in evaluating the treatment efficacy of neoadjuvant treatment in patients with resectable and borderline resectable pancreatic ductal adenocarcinoma: Results of a dual‐center study. Ann Gastroenterol Surg. 2020; 00: 1– 9. https://doi.org/10.1002/ags3.12418

Results of a Randomized Clinical Study of Gemcitabine Plus Nab-Paclitaxel Versus Gemcitabine Plus S-1 as Neoadjuvant Chemotherapy for Resectable and Borderline Resectable Pancreatic Ductal Adenocarcinoma (RCT, CSGO-HBP-015)

The version of record of this article, first published in Annals of Surgical Oncology, is available online at Publisher’s website: https://doi.org/10.1245/s10434-024-15199-8.Background: The optimal neoadjuvant chemotherapy (NAC) regimen for patients with localized pancreatic ductal adenocarcinoma (PDAC) remains uncertain. This trial aimed to evaluate the efficacy and safety of two neoadjuvant chemotherapy (NAC) regimens, gemcitabine plus nab-paclitaxel (GA) and gemcitabine plus S-1 (GS), in patients with resectable/borderline-resectable (R/BR) PDAC. Patients and Methods: Treatment-naïve patients with R/BR-PDAC were enrolled and randomly allocated. They received two cycles (2 months) of each standard protocol, followed by radical surgery for those without tumor progression in general hospitals belonging to our intergroup. The primary endpoint was to determine the superior regimen on the basis of achieving a 10% increase in the rate of patients with progression-free survival (PFS) at 2 years from allocation. Results: A total of 100 patients were enrolled, with 94 patients randomly assigned to the GS arm (N = 46) or GA arm (N = 48). The 2-year PFS rates did not show the stipulated difference [GA, 31% (24–38%)/GS, 26% (18–33%)], but the Kaplan–Myer analysis showed significance (median PFS, GA/GS 14 months/9 months, P = 0.048; HR 0.71). Secondary endpoint comparisons yielded the following results (GA/GS arm, P-value): rates of severe adverse events during NAC, 73%/78%, P = 0.55; completion rates of the stipulated NAC, 92%/83%, P = 0.71; resection rates, 85%/72%, P = 0.10; average tumor marker (CA19-9) reduction rates, −50%/−21%, P = 0.01; average numbers of lymph node metastasis, 1.7/3.2, P = 0.04; and median overall survival times, 42/22 months, P = 0.26. Conclusions: This study found that GA and GS are viable neoadjuvant treatment regimens in R/BR-PDAC. Although the GA group exhibited a favorable PFS outcome, the primary endpoint was not achieved

KLK10 derived from tumor endothelial cells accelerates colon cancer cell proliferation and hematogenous liver metastasis formation

Kato K., Noda T., Kobayashi S., et al. KLK10 derived from tumor endothelial cells accelerates colon cancer cell proliferation and hematogenous liver metastasis formation. Cancer Science , (2024); https://doi.org/10.1111/cas.16144.Tumor endothelial cells (TECs), which are thought to be structurally and functionally different from normal endothelial cells (NECs), are increasingly attracting attention as a therapeutic target in hypervascular malignancies. Although colorectal liver metastasis (CRLM) tumors are hypovascular, inhibitors of angiogenesis are a key drug in multidisciplinary therapy, and TECs might be involved in the development and progression of cancer. Here, we analyzed the function of TEC in the CRLM tumor microenvironment. We used a murine colon cancer cell line (CT26) and isolated TECs from CRLM tumors. TECs showed higher proliferation and migration than NECs. Coinjection of CT26 and TECs yielded rapid tumor formation in vivo. Immunofluorescence analysis showed that coinjection of CT26 and TECs increased vessel formation and Ki-67+ cells. Transcriptome analysis identified kallikrein-related peptide 10 (KLK10) as a candidate target. Coinjection of CT26 and TECs after KLK10 downregulation with siRNA suppressed tumor formation in vivo. TEC secretion of KLK10 decreased after KLK10 downregulation, and conditioned medium after KLK10 knockdown in TECs suppressed CT26 proliferative activity. Double immunofluorescence staining of KLK10 and CD31 in CRLM tissues revealed a significant correlation between poor prognosis and positive KLK10 expression in TECs and tumor cells. On multivariate analysis, KLK10 expression was an independent prognostic factor in disease-free survival. In conclusion, KLK10 derived from TECs accelerates colon cancer cell proliferation and hematogenous liver metastasis formation. KLK10 in TECs might offer a promising therapeutic target in CRLM

Skeletal Myoblast Cells Enhance the Function of Transplanted Islets in Diabetic Mice

Kado T., Tomimaru Y., Kobayashi S., et al. Skeletal Myoblast Cells Enhance the Function of Transplanted Islets in Diabetic Mice. Journal of Diabetes Research 2024, 5574968 (2024); https://doi.org/10.1155/2024/5574968.Islet transplantation (ITx) is an established and safe alternative to pancreas transplantation for type 1 diabetes mellitus (T1DM) patients. However, most ITx recipients lose insulin independence by 3 years after ITx due to early graft loss, such that multiple donors are required to achieve insulin independence. In the present study, we investigated whether skeletal myoblast cells could be beneficial for promoting angiogenesis and maintaining the differentiated phenotypes of islets. In vitro experiments showed that the myoblast cells secreted angiogenesis-related cytokines (vascular endothelial growth factor (VEGF), hepatocyte growth factor (HGF), and stromal-derived factor-1α (SDF-1α)), contributed to maintenance of differentiated islet phenotypes, and enhanced islet cell insulin secretion capacity. To verify these findings in vivo, we transplanted islets alone or with myoblast cells under the kidney capsule of streptozotocin-induced diabetic mice. Compared with islets alone, the group bearing islets with myoblast cells had a significantly lower average blood glucose level. Histological examination revealed that transplants with islets plus myoblast cells were associated with a significantly larger insulin-positive area and significantly higher number of CD31-positive microvessels compared to islets alone. Furthermore, islets cotransplanted with myoblast cells showed JAK-STAT signaling activation. Our results suggest two possible mechanisms underlying enhancement of islet graft function with myoblast cells cotransplantation: "indirect effects"mediated by angiogenesis and "direct effects"of myoblast cells on islets via the JAK-STAT cascade. Overall, these findings suggest that skeletal myoblast cells enhance the function of transplanted islets, implying clinical potential for a novel ITx procedure involving myoblast cells for patients with diabetes

Significance of signal recognition particle 9 nuclear translocation: Implications for pancreatic cancer prognosis and functionality

Sato H., Meng S., Sasaki K., et al. Significance of signal recognition particle 9 nuclear translocation: Implications for pancreatic cancer prognosis and functionality. International Journal of Oncology 65, 74 (2024); https://doi.org/10.3892/ijo.2024.5662.Signal recognition particles (SRPs) are essential for regulating intracellular protein transport and secretion. Patients with tumors with high SRP9 expression tend to have a poorer overall survival. However, to the best of our knowledge, no reports have described the relationship between SRP9 localization and prognosis in pancreatic cancer. Thus, the present study aimed to investigate this relationship. Immunohistochemical staining for SRP9 using excised specimens from pancreatic cancer surgery cases without preoperative chemotherapy or radiotherapy showed that SRP9 was preferentially expressed in the nucleus of the cancerous regions in some cases, which was hardly detected in other cases, indicating that SRP9 was transported to the nucleus in the former cases. To compare the prognosis of patients with SRP9 nuclear translocation, patients were divided into two groups: Those with a nuclear translocation rate of >50% and those with a nuclear translocation rate of ≤50%. The nuclear translocation rate of >50% group had a significantly better recurrence-free survival than the nuclear translocation rate of ≤50% group (P=0.037). Subsequent in vitro experiments were conducted; notably, the nuclear translocation rate of SRP9 was reduced under amino acid-deficient conditions, suggesting that multiple factors are involved in this phenomenon. To further study the function of SRP9 nuclear translocation, in vitro experiments were performed by introducing SRP9 splicing variants (v1 and v2) and their deletion mutants lacking C-terminal regions into MiaPaCa pancreatic cancer cells. The results demonstrated that both splicing variants showed nuclear translocation regardless of the C-terminal deletions, suggesting the role of the N-terminal regions. Given that SRP9 is an RNA-binding protein, the study of RNA immunoprecipitation revealed that signaling pathways involved in cancer progression and protein translation were downregulated in nuclear-translocated v1 and v2. Undoubtedly, further studies of the nuclear translocation of SRP9 will open an avenue to optimize the precise evaluation and therapeutic control of pancreatic cancer