Digestive system deep infiltrating endometriosis: What do we know

Digestive system infiltrating endometriosis (DSIE) is an uncommon form of endometriosis in the digestive system. DSIE often occurs in the intestines (especially the sigmoid rectum), liver, gallbladder and pancreas. Clinically, DSIE presents with the same symptoms as endometriosis, including cyclic pain, bleeding and infertility, in addition to specific biliary/intestinal obstruction and gastrointestinal bleeding. Compared to general endometriosis, DSIE has unique biological behaviour and pathophysiological mechanisms. Most DSIEs are deep invasive endometrioses, characterized by metastasis to the lymph nodes and lymphatic vessels, angiogenesis, peripheral nerve recruitment, fibrosis and invasion of surrounding tissues. DSIE-related peripheral angiogenesis is divided into three patterns: angiogenesis, vasculogenesis and inosculation. These patterns are regulated by interactions between multiple hypoxia-hormone cytokines. The nerve growth factors regulate the extensive neurofibril recruitment in DSIE lesions, which accounts for severe symptoms of deep pain. They are also associated with fibrosis and the aggressiveness of DSIE. Cyclic changes in DSIE lesions, recurrent inflammation and oxidative stress promote repeated tissue injury and repair (ReTIAR) mechanisms in the lesions, accelerating fibril formation and cancer-related mutations. Similar to malignant tumours, DSIE can also exhibit aggressiveness derived from collective cell migration mediated by E-cadherin and N-cadherin. This often makes DSIE misdiagnosed as a malignant tumour of the digestive system in clinical practice. In addition to surgery, novel treatments are urgently required to effectively eradicate this lesion.

Exosomes: a significant medium for regulating drug resistance through cargo delivery

Exosomes are small lipid nanovesicles with a diameter of 30-150 nm. They are present in all body fluids and are actively secreted by the majority of cells through the process of exocytosis. Exosomes play an essential role in intercellular communication and act as significant molecular carriers in regulating various physiological and pathological processes, such as the emergence of drug resistance in tumors. Tumor-associated exosomes transfer drug resistance to other tumor cells by releasing substances such as multidrug resistance proteins and miRNAs through exosomes. These substances change the cell phenotype, making it resistant to drugs. Tumor-associated exosomes also play a role in impacting drug resistance in other cells, like immune cells and stromal cells. Exosomes alter the behavior and function of these cells to help tumor cells evade immune surveillance and form a tumor niche. In addition, exosomes also export substances such as tumoricidal drugs and neutralizing antibody drugs to help tumor cells resist drug therapy. In this review, we summarize the mechanisms of exosomes in promoting drug resistance by delivering cargo in the context of the tumor microenvironment (TME).

SPARC is a Novel Prognostic Biomarker for Ovarian Cancer and Associated with Immune Signatures and Drug Response

Background: The calcium-binding matricellular glycoprotein (SPARC, secreted protein, acidic and rich in cysteine) belongs to the extracellular-matrix-protein family, and its functions mainly focus on tissue injury, remodeling, and tumorigenesis. The role of SPARC in ovarian cancer remains controversial at present. Methods: We searched SPARC using The Cancer Genome Atlas/Genotype-Tissue Expression (TCGA/GTEx) and other databases to analyze the relationship between its expression level and survival, immunity signatures, and chemical drug response, in ovarian cancer. Additionally, we overexpressed SPARC with plasmids in ovarian cancer SKOV3 and ID8 cell lines, then measured the effects of SPARC on the proliferation, migration, invasiveness, clonality, and stemness of ovarian cancer cells by Cell Counting Kit-8 (CCK8), Transwell, wound healing assay, adhesion assay, plate cloning assay, and soft agar spheroid formation in vitro. The Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses showed the potential signaling pathway for SPARC. Results: The higher expression of SPARC in ovarian cancer is related to more advanced tumor stage, poorer clinical survival, and worse chemical drug response, whereas it is positively correlated with immune signatures. For ovarian cancer phenotypes, higher SPARC expression level promotes cell proliferation, migration, colony formation, and spheroid formation. The GO and KEGG enrichment highlighted the potential molecular mechanisms for SPARC with PI3K-AKT and MAPK signaling regulation. Conclusions: SPARC promotes ovarian cancer progression through proliferation, migration, invasiveness, clonality, and stemness. A high level of expression of SPARC in ovarian cancer patients can be used as a marker of poor prognosis and poor drug response.

Rab3B enhances the stabilization of DDX6 to promote lung adenocarcinoma aggressiveness

BACKGROUND

Liver kinase B1 (LKB1) is frequently mutated in lung adenocarcinoma, and its loss contributes to tumor progression.

METHODS

To identify LKB1 downstream genes that promote lung adenocarcinoma aggressiveness, we performed bioinformatical analysis using publicly available datasets.

RESULTS

Rab3B was upregulated in LKB1-depleted lung adenocarcinoma cells and suppressed by LKB1 overexpression. CREB protein was enriched at the promoter of Rab3B in lung cancer cells. Silencing of CREB abrogated the upregulation of Rab3B upon LKB1 loss. Immunohistochemistry revealed the elevated expression of Rab3B in lung adenocarcinomas relative to adjacent normal tissues. Upregulation of Rab3B was significantly associated with lymph node metastasis, advanced tumor stage, and reduced overall survival in lung adenocarcinoma patients. Knockdown of Rab3B suppressed and overexpression of Rab3B promoted the proliferation, colony formation, and migration of lung adenocarcinoma cells in vitro. In a mouse xenograft model, Rab3B depletion restrained and Rab3B overexpression augmented the growth of lung adenocarcinoma tumors. Mechanistically, Rab3B interacted with DDX6 and enhanced its protein stability. Ectopic expression of DDX6 significantly promoted the proliferation, colony formation, and migration of lung adenocarcinoma cells. DDX6 knockdown phenocopied the effects of Rab3B depletion on lung adenocarcinoma cells. Additionally, DDX6 overexpression partially rescued the aggressive phenotype of Rab3B-depleted lung adenocarcinoma cells.

CONCLUSION

LKB1 deficiency promotes Rab3B upregulation via a CREB-dependent manner. Rab3B interacts with and stabilizes DDX6 protein to accelerate lung adenocarcinoma progression. The Rab3B-DDX6 axis may be potential therapeutic target for lung adenocarcinoma.