Biology subjects

Matsumura, N.

Publications and source records attributed to Matsumura, N..

5 recordsLinked to original sources

bioRxiv2026

A cyclo-DOPA 6-O-glucosyltransferase-mediated route for gomphrenin I biosynthesis in Basella alba and Gomphrena globosa

O_LIBetacyanins are red pigments characteristic of Caryophyllales and show considerable structural diversity, yet the enzymatic basis underlying 6-O-glucosylated betacyanins such as gomphrenin I has remained unclear. In particular, how alternative glucosylation patterns contribute to betacyanin diversification is poorly understood. C_LIO_LIHere, we identified cyclo-DOPA glucosyltransferases from Basella alba and Gomphrena globosa and examined their roles in gomphrenin I biosynthesis using transient expression assays and tobacco BY-2 cell systems. Phylogenetic analyses, structural modelling and site-directed mutagenesis were employed to investigate their functional and structural characteristics. C_LIO_LIBacDOPA5/6GTs catalysed both 5-O- and 6-O-glucosylation of cyclo-DOPA, leading to the production of betanin and gomphrenin I, whereas GgcDOPA6GT specifically mediated gomphrenin I formation. These enzymes belong to distinct subclades within the cDOPA-GT family, and mutational analyses demonstrated essential roles for conserved histidine residues and an -helical region adjacent to the catalytic site. C_LIO_LIThermal stability analyses further showed that gomphrenin I is more thermally stable than betanin, likely due to the formation of an intramolecular hydrogen bond. Together, these results reveal an additional cDOPA6GT-mediated route for gomphrenin I biosynthesis and provide insight into the diversification and functional specialization of betacyanins, linking the position of glucosylation to pigment stability and biochemical properties. C_LI

plant biology↗

bioRxiv2023

Homologous recombination deficiency in cell line libraries does not correlate with in vitro sensitivity to platinum agents or PARP inhibitors

Although preclinical studies for drug discovery and biomarker development are extensively conducted using large publicly available cancer cell line databases, there have been no reports to date that clarify the association between homologous recombination repair deficiency (HRD) and drug sensitivity using these data. We comprehensively analyzed the molecular profiles and drug response screening data from the Cancer Cell Line Encyclopedia. Unexpectedly, gene alterations in BRCA1/2 or homologous recombination repair-related genes, HRD score, or mutational signature 3 were not significantly correlated with sensitivity to platinum agents or PARP inhibitors. Rather, higher HRD scores and mutational signature 3 were significantly associated with resistance to platinum and PARP inhibitors in multiple assays. These findings were consistent when analyses were restricted to breast and ovarian cancer cell lines and when data from the COSMIC Cell Line Project dataset were used. SignificanceIn existing cancer cell line databases, the association between HRD status and sensitivity to platinum or PARP inhibitors differs from that expected from clinical tumor data. This discrepancy may also apply to other tumor characteristics, and researchers should be aware of the potential limitations of cell line data. Structural abstractO_ST_ABSBackgroundC_ST_ABSComprehensive molecular profiling and drug sensitivity screening data from over 1000 cancer cell lines are currently available for preclinical studies including targeted drug discovery and biomarker development. However, there are no reports using these cell line databases to clarify the association between homologous recombination repair deficiency (HRD) and drug sensitivity. MethodsWe investigated the association between HRD status, including gene alterations in the homologous recombination repair (HR) pathway, HRD score, and mutational signature 3, and sensitivity to platinum agents and PARP inhibitors in the Cancer Cell Line Encyclopedia (CCLE) and the COSMIC Cell Line Project (CLP) datasets. ResultsIn the CCLE dataset (n=1182), samples with BRCA alterations, including BRCA1 methylation and BRCA1/2 mutations with locus-specific loss-of-heterozygosity, exhibited higher HRD scores and mutational signature 3. These two scores were positively correlated (r=0.475, p=1.25 x10-52). Unexpectedly, neither BRCA1/2 nor HR-related gene alterations correlated with sensitivity to platinum agents or PARP inhibitors. Instead, significantly positive correlations were observed between drug-response AUC values and HRD scores in 60% (6/10) of platinum agent assays, and in 43% (6/14) PARP inhibitor assays, while no significant negative correlation was observed. Similar results were obtained in the analysis with mutational signature 3. These findings were consistent in analyses limited to ovarian and breast cancer cell lines and in the CLP dataset, indicating samples with HRD showed resistance rather than sensitivity to these drugs. ConclusionIn existing cancer cell line databases, the association between HRD status and sensitivity to platinum and PARP inhibitors differs from that expected from clinical tumor data. This discrepancy may also apply to other tumor characteristics, and investigators should be aware of the potential limitations of cell line data.

cancer biology↗

bioRxiv2021

Tertiary lymphoid structures induced by CXCL13-producing CD4+ T cells increase tumor infiltrating CD8+ T cells and B cells in ovarian cancer

BackgroundTertiary lymphoid structures (TLSs) are transient ectopic lymphoid aggregates whose formation might be caused by chronic inflammation states, such as cancer. The presence of TLS is associated with a favorable prognosis in most solid malignancies. The recognition of the relevance of TLS to cancer has led to a growing interest in TLS as an immunomodulatory target to enhance tumor immunity, although how TLSs are induced in the tumor microenvironment (TME) and how they affect patient survival are not well understood. MethodsTLS distribution in relation to tumor infiltrating lymphocytes (TILs) and related gene expression were investigated in high grade serous ovarian cancer (HGSC) specimens. CXCL13 expression, which is strongly associated with TLS, and its localization in immune cells, were examined. We explored the tumor microenvironment for CXCL13 secretion by adding various inflammatory cytokines in vitro. The induction of TLS by CXCL13 was examined in a mouse model of ovarian cancer. ResultsCXCL13 gene expression correlated with TLS formation and the infiltration of T cells and B cells, and was a favorable prognostic factor for HGSC patients. The coexistence of CD8+ T cells and B-cell lineages in the TME was associated with a better prognosis of HGSC and was closely related to the presence of TLSs. CXCL13 expression was predominantly coincident with CD4+ T cells in TLSs and CD8+ T cells in TILs, and shifted from CD4+ T cells to CD21+ follicular dendritic cells as the TLS matured. Although TGF-{beta} was reported to stimulate CXCL13 production, our in vitro results revealed that CXCL13 secretion was promoted in CD4+ T cells under TGF-{beta} + IL-2-restricted conditions and in CD8+ T cells under TGF-{beta} + IL-12-rich conditions. In a mouse model of ovarian cancer, recombinant CXCL13 induced TLSs and enhanced survival by the infiltration of CD8+ T cells. ConclusionsTLS formation was promoted by CXCL13-producing CD4+ T cells and TLSs facilitated the coordinated antitumor responses of cellular and humoral immunity in ovarian cancer.

immunology↗

bioRxiv2021

Frequent PIK3CA mutations in eutopic endometrium of patients with ovarian clear cell carcinoma

Recent studies have reported cancer-associated mutations in normal endometrium. Mutations in eutopic endometrium may lead to endometriosis and endometriosis-associated ovarian cancer. We investigated PIK3CA mutations (PIK3CAm) for three hotspots (E542K, E545K, H1047R) in eutopic endometrium in patients with ovarian cancer and endometriosis from formalin-fixed paraffin-embedded specimens by laser-capture microdissection and droplet digital PCR. The presence of PIK3CAm in eutopic endometrial glands with mutant allele frequency [≥]15% were as follows: ovarian clear cell carcinoma (OCCC) with PIK3CAm in tumors, 20/300 hotspots in 11/14 cases; OCCC without PIK3CAm, 42/78 hotspots in 11/12 cases; high-grade serous ovarian carcinoma, 8/45 hotspots in 3/5 cases; and endometriotic cysts, 5/63 hotspots in 5/6 cases. These rates were more frequent than in non-cancer non-endometriosis controls (7/309 hotspots in 5/17 cases). In OCCC without PIK3CAm, 7/12 (58%) cases showed multiple hotspot mutations in the same eutopic endometrial glands. In 3/54 (5.6%) cases, PIK3CAm was found in eutopic endometrial stroma. Multi-sampling of the OCCC tumors with PIK3CAm showed intratumor heterogeneity in three of eight cases. In two cases, PIK3CAm was detected in the stromal component of the tumor. Homogenous PIK3CAm in the epithelial component of the tumor matched the mutation in eutopic endometrial glands in only one case. Eutopic endometrial glands in ovarian cancer and endometriosis show high frequency of PIK3CAm that is not consistent with tumors, and multiple hotspot mutations are often found in the same glands. Our results suggest that most PIK3CAm in eutopic endometrial glands are passenger rather than driver mutations.

cancer biology↗

bioRxiv2019

Targeting dormant ovarian cancer cells in vitro and in an in vivo model of platinum resistance

ObjectiveOvarian cancer cells often exist in vivo as multicellular spheroids. Spheroid formation in vitro has been used to enrich for cancer stem cell populations from primary tumors. Such spheroids exhibit drug resistance and slow proliferation, suggesting involvement in disease recurrence. Our objectives were to characterize cancer spheroid phenotypes, determine gene expression profiles associated with spheroid forming capacity and to evaluate the responsiveness of spheroids to commonly used and novel therapeutic agents.\n\nMethodsTumorigenic potential was assessed using anchorage independent growth assays in 24 cell lines. Spheroids from cell lines (N=12) and from primary cancers (N=8) were grown on non-adherent tissue culture plates in serum-free media. Cell proliferation was measured using MTT assays and Ki67 immunostaining. Affymetrix HT U133A gene expression data was used to identify differentially expressed genes based on spheroid forming capacity. Matched monolayers and spheroids (N=7 pairs) were tested for response to cisplatin, paclitaxel and 7-hydroxystaurosporine (UCN-01) while mitochondrial inhibition was performed using oligomycin. Xenograft tumors from intraperitoneal injection of CAOV2-GFP/LUC ovarian cancer cells into nude mice were treated with carboplatin to reduce tumor burden followed by secondary treatment with carboplatin, UCN-01, or Oltipraz. Tumor formation and response was monitored using live imaging.\n\nResultsOf 12 cell lines with increased anchorage-independent growth, 8 also formed spheroids under serum-free spheroid culture conditions. Spheroids showed reduced proliferation (p<0.0001) and Ki67 immunostaining (8% versus 87%) relative to monolayer cells. Spheroid forming capacity was associated with increased mitochondrial pathway activity (p [≤] 0.001). The mitochondrial inhibitors, UCN-01 and Oligomycin, demonstrated effectiveness against spheroids, while spheroids were refractory to cisplatin and paclitaxel. By live in vivo imaging, ovarian cancer xenograft tumors were reduced after primary treatment with carboplatin. Continued treatment with carboplatin was accompanied by an increase in tumor signal while there was little or no increase in tumor signal observed with subsequent treatment with UCN-01 or Oltipraz.\n\nConclusionsOur findings suggest that the mitochondrial pathway in spheroids may be an important therapeutic target in preventing disease recurrence.

cancer biology↗