In Vitro and In Vivo Study on the Effect of Lysosome-associated Protein Transmembrane 4 Beta on the Progression of Breast Cancer

The role and regulatory mechanism of lysosome associated protein transmembrane 4β in tumors

The oncogene LAPTM4B (encoding lysosome-associated protein transmembrane-4β), first cloned in hepatocellular carcinoma cells, is located on chromosome 8q22.1 and encodes two isoforms, LAPTM4B-35 and LAPTM4B-24. LAPTM4B proteins have four transmembrane structural domains and are mainly distributed in lysosomal and endosomal membranes of cells. Studies have shown that LAPTM4B is overexpressed in a variety of cancers, in which the genetic polymorphism of LAPTM4B is associated with tumor susceptibility. LAPTM4B also regulates various cell signaling pathways, interacts with autophagy-related proteins and ceramides, and regulates the autophagy process and the release of exosomes, which in turn affect the survival and drug resistance of tumor cells. In conclusion, this paper summarizes recent research on LAPTM4B, aiming to explore the role and potential mechanisms of LAPTM4B in a variety of tumors.

A comprehensive prognostic and immune analysis of LAPTM4B in pan-cancer and Philadelphia chromosome-positive acute lymphoblastic leukemia

Introduction

Lysosomal-associated protein transmembrane-4 beta (LAPTM4B) protein expression was increased in solid tumors, whereas few studies were performed in hematologic malignancies. We aimed to study the effect of the LAPTM4B gene in pan-cancer and Philadelphia chromosome-positive acute B cell lymphoblastic leukemia (Ph+ B-ALL).

Methods

The differential expression, diagnosis, prognosis, genetic and epigenetic alterations, tumor microenvironment, stemness, immune infiltration cells, function enrichment, single-cell analysis, and drug response across cancers were conducted based on multiple computational tools. Additionally, Ph+ B-ALL transgenic mouse model with Laptm4b knockout was used to analyze the function of LAPTM4B in vivo. BrdU incorporation method, flow cytometry, and Witte-lock Witte culture were used to evaluate the roles of LAPTM4B in vitro.

Results

We identified that LAPTM4B expression was increased in various cancers, with significant associations with clinical outcomes. LAPTM4B expression correlated with DNA and RNA methylation patterns and was associated with drug resistance. It also influenced the tumor immune microenvironment, with implications for immunotherapy response. In leukemia, LAPTM4B was expressed in stem cells and associated with specific subtypes. Knockout of LAPTM4B impeded B-ALL progression in mice and reduced cell proliferation and caused G0/G1 arrest in vitro.

Discussion

Our study elucidated the role LAPTM4B that promoted the development and progression in Ph+ B-ALL. Furthermore, LAPTM4B played a diagnostic, prognostic, and immunological factor.

Matrix Metalloproteinase-2 (MMP-2): As an Essential Factor in Cancer Progression

The development of cancer has been a multistep process involving mutation, proliferation, survival, invasion, and metastasis. Of all the characteristics of cancer, metastasis is believed to be the hallmark as it is responsible for the highest number of cancer-related deaths. In connection with this, Matrix metalloproteinases (MMPs), that has a role in metastasis, are one of the novel therapeutic targets. MMPs belong to the family of zinc-dependent endopeptidases and are capable of degrading the components of the extracellular matrix (ECM). The role of MMPs in ECM remodeling includes tissue morphogenesis, uterine cycling, growth, tissue repair, and angiogenesis. During pathological conditions, MMPs play a critical role in the excessive degradation of ECM which includes arthritis, tumour invasion, tumour metastasis, and several other autoimmune disorders. Moreover, they are believed to be involved in many physiological aspects of the cell, such as proliferation, migration, differentiation, angiogenesis, and apoptosis. It is reported that dysregulation of MMP in a variety of cancer subtypes have a dual role in tumour growth and metastasis processes. Further, multiple studies suggest the therapeutic potential of targeting MMP in invading cancer. The expression of MMP-2 correlates with the clinical characteristics of cancer patients, and its expression profile is a new diagnostic and prognostic biomarker for a variety of human diseases. Hence, manipulating the expression or function of MMP-2 may be a potential treatment strategy for different diseases, including cancers. Hence, the present review discusses the therapeutic potential of targeting MMP in various types of cancers and their recent patents.