Identification of calgranulin B interacting proteins and network analysis in gastrointestinal cancer cells

FK506-binding protein 2 (FKBP13) inhibit Bax-induced apoptosis in Saccharomyces cerevisiae (yeast)

FK506-binding protein 2 (FKBP13) is a part of the immunophilin protein family involved in immunoregulation. It is also believed to operate as a factor in membrane cytoskeletal framework and as an ER chaperone. FKBP2 (FKBP13) and FKBP1 (FKBP12), known as immunophilins, are binding proteins for rapamycin and FK506, which are immunosuppressive drugs. It was suggested that immunophilin-like and immunophilin proteins play significant roles in regulating intracellular calcium and protein folding/sorting, acting as molecular chaperones. Within the 15 mammalian FKBPs known, FKBP1 is merely the only one proven to form complexes with rapamycin and FK506 in the cytosol and facilitate their T cells immunosuppressive effects, FKBP2 is a luminal protein of the endoplasmic reticulum (ER) and is reported to take part in protein folding in the ER. However, little is known about FKBP2 link with apoptosis (either as a pro or anti-apoptotic protein). In this study, FKPB2 protein was co-expressed with the pro-apoptotic protein Bax after a yeast-based human hippocampal cDNA library screening. The yeast strain carrying the Bax gene was transformed with an episomal 2-micron plasmid that encodes the HA-tagged FKBP2 gene. The resultant strain would allow co-expression of Bax and FKBP2 in yeast cells. The results presented here show that a protein involved in protein folding can play a role in protecting yeast cell from Bax-induced apoptosis.

S100A8 and S100A9 in Cancer

S100A8 and S100A9 are Ca²⁺ binding proteins that belong to the S100 family. Primarily expressed in neutrophils and monocytes, S100A8 and S100A9 play critical roles in modulating various inflammatory responses and inflammation-associated diseases. Forming a common heterodimer structure S100A8/A9, S100A8 and S100A9 are widely reported to participate in multiple signaling pathways in tumor cells. Meanwhile, S100A8/A9, S100A8, and S100A9, mainly as promoters, contribute to tumor development, growth and metastasis by interfering with tumor metabolism and the microenvironment. In recent years, the potential of S100A8/A9, S100A9, and S100A8 as tumor diagnostic or prognostic biomarkers has also been demonstrated. In addition, an increasing number of potential therapies targeting S100A8/A9 and related signaling pathways have emerged. In this review, we will first expound on the characteristics of S100A8/A9, S100A9, and S100A8 in-depth, focus on their interactions with tumor cells and microenvironments, and then discuss their clinical applications as biomarkers and therapeutic targets. We also highlight current limitations and look into the future of S100A8/A9 targeted anti-cancer therapy.

Rapamycin-filgrastim combination therapy ameliorates portal hypertension-induced splenomegaly: Role of β actin and S100A9 proteins modulation

Objectives

Thioacetamide (TAA) was administered to induce an animal model of liver disease with secondary splenomegaly to assess the mechanisms underlying the effects of rapamycin and filgrastim when taken separately or in combination on the biochemical and histopathological aspects of the liver and spleen.

Materials and Methods

Thirty adult male albino rats were divided into five groups (control, TAA-treated group, TAA+rapamycin, TAA+filgrastim, and TAA+rapamycin+filgrastim group). We measured relative liver and spleen weights, serum levels of alanine transaminase (ALT), aspartate transaminase (AST), and albumin. Molecular docking modeling and histopathological examination of liver and spleen sections with hematoxylin and eosin and Masson trichrome staining with immunohistochemical detection of splenic CD3 and CD20 lymphocytes, S100A9 and β actin antibodies were detected. Morphometric and statistical analyses of the results were performed.

Results

TAA administration altered the histological structure of the liver and spleen and impaired liver function. It increased the expression of splenic CD3, CD20 lymphocytes, and S100A9 while diminishing the expression of β actin. Each of rapamycin and filgrastim, when administered separately, improved liver and spleen indices and liver function, but rapamycin did not affect the albumin level. They lowered splenic B and T lymphocyte levels. Expression levels of S100A9 showed down-regulation while β actin levels were up-regulated when compared with TAA. Combination therapy improved liver and spleen tissue pathology and significantly ameliorated the expression of splenic lymphocytes through regulation of S100A9 and β actin expression.

Conclusion

The synergistic effect of combination therapy was dependent on the regulation of splenic S100A9 and β actin levels.

FKBP9 promotes the malignant behavior of glioblastoma cells and confers resistance to endoplasmic reticulum stress inducers

Background

FK506-binding protein 9 (FKBP9) is amplified in high-grade gliomas (HGGs). However, the roles and mechanism(s) of FKBP9 in glioma are unknown.

Methods

The expression of FKBP9 in clinical glioma tissues was detected by immunohistochemistry (IHC). The correlation between FKBP9 expression levels and the clinical prognosis of glioma patients was examined by bioinformatic analysis. Glioblastoma (GBM) cell lines stably depleted of FKBP9 were established using lentiviruses expressing shRNAs against FKBP9. The effects of FKBP9 on GBM cells were determined by cell-based analyses, including anchorage-independent growth, spheroid formation, transwell invasion assay, confocal microscopy, immunoblot (IB) and coimmunoprecipitation assays. In vivo tumor growth was determined in both chick chorioallantoic membrane (CAM) and mouse xenograft models.

Results

High FKBP9 expression correlated with poor prognosis in glioma patients. Knockdown of FKBP9 markedly suppressed the malignant phenotype of GBM cells in vitro and inhibited tumor growth in vivo. Mechanistically, FKBP9 expression induced the activation of p38MAPK signaling via ASK1. Furthermore, ASK1-p38 signaling contributed to the FKBP9-mediated effects on GBM cell clonogenic growth. In addition, depletion of FKBP9 activated the IRE1α-XBP1 pathway, which played a role in the FKBP9-mediated oncogenic effects. Importantly, FKBP9 expression conferred GBM cell resistance to endoplasmic reticulum (ER) stress inducers that caused FKBP9 ubiquitination and degradation.

Conclusions

Our findings suggest an oncogenic role for FKBP9 in GBM and reveal FKBP9 as a novel mediator in the IRE1α-XBP1 pathway.

Targeting the IGF1R Pathway in Breast Cancer Using Antisense lncRNA-Mediated Promoter cis Competition

Aberrant insulin-like growth factor I receptor (IGF1R) signaling pathway serves as a well-established target for cancer drug therapy. The intragenic antisense long noncoding RNA (lncRNA) IRAIN, a putative tumor suppressor, is downregulated in breast cancer cells, while IGF1R is overexpressed, leading to an abnormal IGF1R/IRAIN ratio that promotes tumor growth. To precisely target this pathway, we developed an “antisense lncRNA-mediated intragenic cis competition” (ALIC) approach to therapeutically correct the elevated IGF1R/IRAIN bias in breast cancer cells. We used CRISPR-Cas9 gene editing to target the weak promoter of IRAIN antisense lncRNA and showed that in targeted clones, intragenic activation of the antisense lncRNA potently competed in cis with the promoter of the IGF1R sense mRNA. Notably, the normalization of IGF1R/IRAIN transcription inhibited the IGF1R signaling pathway in breast cancer cells, decreasing cell proliferation, tumor sphere formation, migration, and invasion. Using “nuclear RNA reverse transcription-associated trap” sequencing, we uncovered an IRAIN lncRNA-specific interactome containing gene targets involved in cell metastasis, signaling pathways, and cell immortalization. These data suggest that aberrantly upregulated IGF1R in breast cancer cells can be precisely targeted by cis transcription competition, thus providing a useful strategy to target disease genes in the development of novel precision medicine therapies.