Prognostic significance of LDL receptor-related protein 1B in patients with gastric cancer

Implication of IZUMO2 in the cell-in-cell phenomenon: A potential therapeutic target for triple-negative breast cancer

BACKGROUND

Triple-negative breast cancer (TNBC) is characterized by the loss of estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2. The aggressive clinicopathological features and resistance to currently available therapeutics of the disease warrant an urgent need for the development of novel alternate therapeutic options. We have previously reported adiponectin-expressing regulatory T cells (A-Tregs), which can induce apoptosis in TNBC through the cell-in-cell phenomenon. In this study, we aimed to elucidate the molecule that allows TNBC cells to engulf A-Tregs.

METHODS

A monoclonal antibody, which repressed the engulfment of A-Tregs by TNBC cells, was developed. Immunoprecipitation followed by mass spectrometry and small interfering RNAs-mediated gene silencing was performed to characterize the antigen.

RESULTS

We successfully generated a monoclonal antibody, designated G1D7, which abrogated the engulfment of A-Tregs by TNBC and subsequent A-Treg-mediated apoptosis. G1D7 detected the immunoglobulin-like type I membrane protein IZUMO2, a molecule related to IZUMO1 that is essential for cell-cell membrane binding and fusion of sperm to oocyte.

CONCLUSION

The findings highlight the importance of IZUMO2 on TNBC cells in facilitating the cell-in-cell phenomenon by A-Tregs.

Prognostic Implications of LRP1B and Its Relationship with the Tumor-Infiltrating Immune Cells in Gastric Cancer

BACKGROUND

Recent studies have shown that low-density lipoprotein receptor-related protein 1b (LRP1B), as a potential tumor suppressor, is implicated in the response to immunotherapy. The frequency of LRP1B mutation gene is high in many cancers, but its role in gastric cancer (GC) has not been determined.

METHODS

The prognostic value of LRP1B mutation in a cohort containing 100 patients having received radical gastrectomy for stage II-III GC was explored. By analyzing the data of LRP1B mRNA, the risk score of differentially expressed genes (DEGs) between LRP1B mutation-type and wild-type was constructed based on the TCGA-STAD cohort. The infiltration of tumor immune cells was evaluated by the CYBERSORT algorithm and verified by immunohistochemistry.

RESULTS

LRP1B gene mutation was an independent risk factor for disease-free survival (DFS) in GC patients (HR = 2.57, 95% CI: 1.28-5.14, p = 0.008). The Kaplan-Meier curve demonstrated a shorter survival time in high-risk patients stratified according to risk score (p < 0.0001). CYBERSORT analysis showed that the DEGs were mainly concentrated in CD4+ T cells and macrophages. TIMER analysis suggested that LRP1B expression was associated with the infiltration of CD4+ T cells and macrophages. Immunohistochemistry demonstrated that LRP1B was expressed in the tumor cells (TCs) and immune cells in 16/89 and 26/89 of the cohort, respectively. LRP1B-positive TCs were associated with higher levels of CD4+ T cells, CD8+ T cells, and CD86/CD163 (p < 0.05). Multivariate analysis showed that LRP1B-positive TCs represented an independent protective factor of DFS in GC patients (HR = 0.43, 95% CI: 0.10-0.93, p = 0.042).

CONCLUSIONS

LRP1B has a high prognostic value in GC. LRP1B may stimulate tumor immune cell infiltration to provide GC patients with survival benefits.

Adiponectin-expressing Treg-containing T cell fraction inhibits tumor growth in orthotopically implanted triple-negative breast cancer

BACKGROUND

In our previous study, we identified a population of adiponectin expressing regulatory T cells (Tregs) residing within thymic nurse cell complexes, which were capable of inhibiting the development of breast cancer in vitro. Triple-negative breast cancer (TNBC) with no proper treatment at present is characterized by the absence of estrogen receptor, progesterone receptor, and human epidermal growth factor receptor-2. In this study, we aimed to investigate the potential of a cultured T cell fraction comprising adiponectin-expressing Tregs, referred to as A-TregTF (adiponectin-expressing Treg-containing T cell fraction), in inhibiting the progression of TNBC in vivo.

METHODS

The efficacy of a spontaneously expanding T cell fraction comprising adiponectin-expressing Treg in inhibiting tumor growth was analyzed in a murine orthotopic 4 T1-Luc TNBC model.

RESULTS

The treatment with T cell fraction containing adiponectin-expressing Tregs significantly inhibited the growth and metastasis of orthotopically transplanted 4 T1-Luc tumor cells. Histopathological examination further revealed that the adiponectin-expressing Tregs infiltrated the tumor tissue via a cell-in-cell mechanism and were found to be specifically localized around the necrotic areas.

CONCLUSIONS

Based on our findings, the T cell fraction comprising adiponectin-expressing Tregs, represents a potential candidate for adoptive cell therapy against TNBC.

Potential activity of adiponectin-expressing regulatory T cells against triple-negative breast cancer cells through the cell-in-cell phenomenon

BACKGROUND

A population of regulatory T cells (Treg), which reside within thymic nurse cell complexes, express adiponectin and abrogate breast cancer development in transgenic mice. In this study, we examined whether adiponectin-expressing Treg could impair triple-negative breast cancer, which is defined by a lack of estrogen receptors, progesterone receptors, and human epidermal growth factor receptor-2.

METHODS

CD4- and CD25-positive cells were sorted from cultured T lymphocytes of a previously characterized experimental thymic tumor model composed of thymic nurse cells and abundant lymphoid stroma. These sorted cells were examined for FOXP3 and adiponectin immunoreactivity and subsequently exposed to triple-negative breast cancer MDA-MB-157 and -231 cells.

RESULTS

Adiponectin-expressing Treg were obtained by CD4- and CD25-positive sorting and cell death was induced in triple-negative breast cancer cells through the cell-in-cell phenomenon.

CONCLUSIONS

Adiponectin-expressing Treg may be candidates for adoptive cell therapy against triple-negative breast cancer.

Experimental model of micronodular thymic neoplasm with lymphoid stroma

BACKGROUND

Micronodular thymic neoplasm with lymphoid stroma (MNT), a subtype of thymic tumor, is histopathologically characterized by micronodular thymic epithelial cell nests with lymphoid stroma. Despite the distinct histopathology of MNT, its pathogenesis remains unclear.

METHODS

In this study, we aimed to examine a thymic tumor harboring thymic epithelial and lymphoid cells in a nonobese diabetic/severe combined immunodeficiency mouse.

RESULTS

The excised tumor cells were cultured in vitro and comprised epithelial tumor cells and lymphoid cells. During a three-dimensional cell culture, the epithelial tumor cells formed micronodular cell nests surrounded by lymphoid stroma. Notably, the lymphoid cells underwent apoptosis when they were separated from the epithelial tumor cells. Cutaneous transplantation of the cultured epithelial cells with splenocytes from BALB/c mice led to tumor formation, and these cells demonstrated a histopathology similar to that of human MNT in a nonobese diabetic/severe combined immunodeficiency mouse.

CONCLUSION

Given its overlapping features with human MNT, the transplanted tumor could serve as an experimental model of this disease.

Integrative analysis of the proteome and transcriptome in gastric cancer identified LRP1B as a potential biomarker

Background: The aim of this study was to discover unique membrane proteins associated with gastric cancer (GC) in proteomics analysis. Methods: Using a data-independent acquisition strategy, we compared the relative expression levels of membrane proteins in GC. Results: A total of 2774 differentially expressed membrane proteins were identified between GC and normal cell lines. Conjoint analysis of transcriptomes and proteomes provided 11 potential biomarkers (GPRC5A, PSAT1, NUDCD1, RCC2, IPO4, FAM91A1, KANK2, PRADC1, NME4, METTL7A and LRP1B) for further exploration. Downregulation of LRP1B in GC was validated by immunohistochemistry. Moreover, LRP1B demonstrated an area under the receiver operating characteristic curve of 0.917 in differentiating GC from normal tissues. Conclusion: LRP1B was identified as a meaningful indicator assisting in GC detection and labeling of tumor boundaries.

The Role of Lipid Metabolism in Gastric Cancer

Gastric cancer has been one of the most common cancers worldwide with extensive metastasis and high mortality. Chemotherapy has been found as a main treatment for metastatic gastric cancer, whereas drug resistance limits the effectiveness of chemotherapy and leads to treatment failure. Chemotherapy resistance in gastric cancer has a complex and multifactorial mechanism, among which lipid metabolism plays a vital role. Increased synthesis of new lipids or uptake of exogenous lipids can facilitate the rapid growth of cancer cells and tumor formation. Lipids form the structural basis of biofilms while serving as signal molecules and energy sources. It is noteworthy that lipid metabolism is capable of inducing drug resistance in gastric cancer cells by reshaping the tumor micro-environment. In this study, new mechanisms of lipid metabolism in gastric cancer and the metabolic pathways correlated with chemotherapy resistance are reviewed. In particular, we discuss the effects of lipid metabolism on autophagy, biomarkers treatment and drug resistance in gastric cancer from the perspective of lipid metabolism. In brief, new insights can be gained into the development of promising therapies through an in-depth investigation of the mechanism of lipid metabolism reprogramming and resensitization to chemotherapy in gastric cancer cells, and scientific treatment can be provided by applying lipid-key enzyme inhibitors as cancer chemical sensitizers in clinical settings.

Clinicopathological characteristics, survival outcomes, and genetic alterations of younger patients with gastric cancer: Results from the China National Cancer Center and cBioPortal datasets

Background

The survival outcomes of younger patients with gastric cancer (GC) have remained controversial. This study explores the clinicopathological characteristics, survival outcomes, and genetic alterations of younger and older patients with GC.

Methods

Patients with GC were identified from the China National Cancer Center Gastric Cancer Database (NCCGCDB) during 1998–2018. Survival analysis was conducted using Kaplan–Meier estimates and Cox proportional hazards models. Sequencing datasets were enrolled from The Cancer Genome Atlas (TCGA) and Memorial Sloan–Kettering Cancer Center (MSKCC) databases.

Results

A total of 1146 younger (<40 years of age) and 16,988 older (≥40 years of age) cases were included in the study. Younger patients had more poorly differentiated lesions than older patients (53.7% vs. 33.8%, respectively; p < 0.0001), and were more often pTNM stage IV (19.5% vs. 11.8%, respectively; p < 0.001). The 5‐year overall survival (OS) of patients from the NCCGCDB increased from 1998 to 2018. Younger patients with pTNM stage III had a lower survival rate than older patients (p = 0.014), while no differences by age were observed at other stages. The mutation frequency of the LRP1B, GNAS, APC, and KMT2D genes was higher for older than younger patients (p < 0.05 for all genes). While not significantly different, younger patients from the TCGA and MSKCC databases were more likely to have CDH1, RHOA, and CTNNB1 gene mutations.

Conclusions

A stable proportion and improved survival of younger patients were reported using NCCGCDB data. Younger patients with pTNM stage III had lower rates of survival than older patients. Distinct molecular characteristics were identified in younger GC patients which may partly explain the histopathology and prognosis specific to this subpopulation.

Rab11-FIP1/RCP Functions as a Major Signalling Hub in the Oncogenic Roles of Mutant p53 in Cancer

Rab11-FIP1 is a Rab effector protein that is involved in endosomal recycling and trafficking of various molecules throughout the endocytic compartments of the cell. The consequence of this can be increased secretion or increased membrane expression of those molecules. In general, expression of Rab11-FIP1 coincides with more tumourigenic and metastatic cell behaviour. Rab11-FIP1 can work in concert with oncogenes such as mutant p53, but has also been speculated to be an oncogene in its own right. In this perspective, we will discuss and speculate upon our observations that mutant p53 promotes Rab11-FIP1 function to not only promote invasive behaviour, but also chemoresistance by regulating a multitude of different proteins.

LRP1B: A Giant Lost in Cancer Translation

Low-density lipoprotein receptor-related protein 1B (LRP1B) is a giant member of the LDLR protein family, which includes several structurally homologous cell surface receptors with a wide range of biological functions from cargo transport to cell signaling. LRP1B is among the most altered genes in human cancer overall. Found frequently inactivated by several genetic and epigenetic mechanisms, it has mostly been regarded as a putative tumor suppressor. Still, limitations in LRP1B studies exist, in particular associated with its huge size. Therefore, LRP1B expression and function in cancer remains to be fully unveiled. This review addresses the current understanding of LRP1B and the studies that shed a light on the LRP1B structure and ligands. It goes further in presenting increasing knowledge brought by technical and methodological advances that allow to better manipulate LRP1B expression in cells and to more thoroughly explore its expression and mutation status. New evidence is pushing towards the increased relevance of LRP1B in cancer as a potential target or translational prognosis and response to therapy biomarker.