Integrin α7 correlates with worse clinical features and prognosis, and its knockdown inhibits cell proliferation and stemness in tongue squamous cell carcinoma

ROS-mediated ITGB5 promotes tongue squamous cell carcinoma metastasis through epithelial mesenchymal transition and cell adhesion signal pathway

PURPOSE

Integrin β5 (ITGB5) is an integrin β subunit member widely expressed in the human bodies, especially in cancer cells and tissues, which is a key factor in promoting tumor metastasis. In this study we investigated the differential expression of ITGB5 in tongue squamous cell carcinoma (TSCC), especially in those with lymph node metastasis, and revealed the possible mechanism.

METHODS

The expression of ITGB5 in TSCC was analyzed by database and verified by immunohistochemistry through 135 TSCC patients' tissue sections from Sun Yat-sen Memorial Hospital and Guangzhou First People's Hospital. The relationship between ITGB5 and lymph node metastasis or prognosis was analyzed retrospectively. The effects of ITGB5 on TSCC cells were examined through knocking down or overexpression and its possible regulator and signal pathway were explored.

RESULTS

The expression of ITGB5 in TSCC was higher than that in adjacent tissue, and the expression in patients with lymph node metastasis was higher than that in patients without lymph node metastasis. The high expression of ITGB5 predicted a worse prognosis. Knock down of ITGB5 suppressed invasion and migration of TSCC cells, while overexpression of ITGB5 contributed to invasion and migration. Reactive oxygen species (ROS) regulated epithelial mesenchymal transition (EMT), and we further verified that ROS enhanced the expression of ITGB5 to promote the metastasis of TSCC. Mechanistically, ITGB5 functions through cell adhesion signal pathway.

CONCLUSION

The increased expression of ITGB5 in tongue squamous cell carcinoma with lymph node metastasis may be a potential target for evaluating lymph node metastasis and worse prognosis of tongue squamous cell carcinoma. Scavenge of ROS or knock down of ITGB5 may be the strategies to overcome metastasis of TSCC.

Integrins in cancer stem cells

Integrins are a class of adhesion receptors on cell membranes, consisting of α and β subunits. By binding to the extracellular matrix, integrins activate intracellular signaling pathways, participating in every step of cancer initiation and progression. Tumor stem cells possess self-renewal and self-differentiation abilities, along with strong tumorigenic potential. In this review, we discussed the role of integrins in cancer, with a focus on their impact on tumor stem cells and tumor stemness. This will aid in targeting tumor stem cells as a therapeutic approach, leading to the exploration of novel cancer treatment strategies.

Integrins as the pivotal regulators of cisplatin response in tumor cells

Cisplatin (CDDP) is a widely used first-line chemotherapeutic drug in various cancers. However, CDDP resistance is frequently observed in cancer patients. Therefore, it is required to evaluate the molecular mechanisms associated with CDDP resistance to improve prognosis among cancer patients. Integrins are critical factors involved in tumor metastasis that regulate cell-matrix and cell-cell interactions. They modulate several cellular mechanisms including proliferation, invasion, angiogenesis, polarity, and chemo resistance. Modification of integrin expression levels can be associated with both tumor progression and inhibition. Integrins are also involved in drug resistance of various solid tumors through modulation of the tumor cell interactions with interstitial matrix and extracellular matrix (ECM). Therefore, in the present review we discussed the role of integrin protein family in regulation of CDDP response in tumor cells. It has been reported that integrins mainly promoted the CDDP resistance through interaction with PI3K/AKT, MAPK, and WNT signaling pathways. They also regulated the CDDP mediated apoptosis in tumor cells. This review paves the way to suggest the integrins as the reliable therapeutic targets to improve CDDP response in tumor cells.

The characteristics and the multiple functions of integrin β1 in human cancers

Integrins, which consist of two non-covalently linked α and β subunits, play a crucial role in cell-cell adhesion and cell-extracellular matrix (ECM) interactions. Among them, integrin β1 is the most common subunit and has emerged as a key mediator in cancer, influencing various aspects of cancer progression, including cell motility, adhesion, migration, proliferation, differentiation and chemotherapy resistance. However, given the complexity and sometimes contradictory characteristics, targeting integrin β1 for therapeutics has been a challenge. The emerging understanding of the mechanisms regulating by integrin β1 may guide the development of new strategies for anti-cancer therapy. In this review, we summarize the multiple functions of integrin β1 and signaling pathways which underlie the involvement of integrin β1 in several malignant cancers. Our review suggests the possibility of using integrin β1 as a therapeutic target and highlights the need for patient stratification based on expression of different integrin receptors in future clinical studies.

A novel prognostic model based on three integrin subunit genes-related signature for bladder cancer

Background

Presently, a comprehensive analysis of integrin subunit genes (ITGs) in bladder cancer (BLCA) is absent. This study endeavored to thoroughly analyze the utility of ITGs in BLCA through computer algorithm-based bioinformatics.

Methods

BLCA-related materials were sourced from reputable databases, The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO). R software-based bioinformatics analyses included limma-differential expression analysis, survival-Cox analysis, glmnet-Least absolute shrinkage and selection operator (LASSO), clusterProfiler-functional annotation, and gsva-estimate-immune landscape analysis. The expression difference of key genes was verified by quantitative real-time polymerase chain reaction (qRT-PCR).

Results

Among the 11 ITGs that were abnormally expressed in BLCA, ITGA7, ITGA5, and ITGB6 were categorized as the optimal variables for structuring the risk model. The high-risk subcategories were typified by brief survival, abysmal prognosis, prominent immune and stromal markers, and depressed tumor purity. The risk model was also an isolated indicator of the impact of clinical outcomes in BLCA patients. Moreover, the risk model, specifically the high-risk subcategory with inferior prognosis, became heavily interlinked with the immune-inflammatory response and smooth muscle contraction and relaxation.

Conclusion

This study determined three ITGs with prognostic values (ITGA7, ITGA5, and ITGB6), composed a novel (ITG-associated) prognostic gene signature, and preliminarily probed the latent molecular mechanisms of the model.

LncRNA KASRT Serves as a Potential Treatment Target by Regulating SRSF1-Related KLF6 Alternative Splicing and the P21/CCND1 Pathway in Osteosarcoma: An In Vitro and In Vivo Study

Purpose

Long non-coding RNA KLF6 alternative splicing regulating transcript (lnc-KASRT) locates within the intronic region of SRSF1, possessing the potential to regulate KLF6 alternative splicing to promote carcinogenicity. Then, the current in vitro and in vivo study aimed to investigate the effect of lnc-KASRT on regulating tumor malignant behaviors, and the implication of its interaction with KLF6 alternative splicing in osteosarcoma.

Methods

Lnc-KASRT overexpression or knockdown plasmid was transfected into U-2OS and Saos-2 cells. Then, KLF6-SV1 knockdown plasmid with or without lnc-KASRT overexpression plasmid was transfected into these cells for compensative experiments. In vivo, lnc-KASRT overexpression or knockdown Saos-2 cells were injected in mice for tumor xenograft construction.

Results

Lnc-KASRT expression was increased in most osteosarcoma cell lines compared to control cell line. Lnc-KASRT overexpression promoted cell viability, mobility, and anti-apoptotic marker expression, while reducing apoptosis rate and pro-apoptotic marker expression; meanwhile, it regulated SRSF1, KLF6 alternative splicing (increased KLF6-splice variant 1 (KLF6-SV1), decreased KLF6-wild type (KLF6-WT)), and followed P21/CCND1 pathway in U-2OS/Saos-2 cells. The lnc-KASRT knockdown exhibited opposite trends. Subsequent compensative experiments disclosed that KLF6-SV1 knockdown attenuated most of the tumor-promoting effects of lnc-KASRT overexpression in U-2OS/Saos-2 cells. In vivo experiments further validated that lnc-KASRT enhanced tumor growth and reduced tumor apoptosis; meanwhile, it also increased tumor KLF6-SV1, MMP-1, and MMP-9 expressions but decreased tumor SRSF1 and KLF6-WT expressions in xenograft mice.

Conclusion

Lnc-KASRT serves as a potential treatment target via regulating SRSF1-related KLF6 alternative splicing and following P21/CCND1 pathway in osteosarcoma.

The Biological Functions and Clinical Applications of Integrins in Cancers

Integrins are the adhesion molecules and receptors of extracellular matrix (ECM). They mediate the interactions between cells-cells and cells-ECM. The crosstalk between cancer cells and their microenvironment triggers a variety of critical signaling cues and promotes the malignant phenotype of cancer. As a type of transmembrane protein, integrin-mediated cell adhesion is essential in regulating various biological functions of cancer cells. Recent evidence has shown that integrins present on tumor cells or tumor-associated stromal cells are involved in ECM remodeling, and as mechanotransducers sensing changes in the biophysical properties of the ECM, which contribute to cancer metastasis, stemness and drug resistance. In this review, we outline the mechanism of integrin-mediated effects on biological changes of cancers and highlight the current status of clinical treatments by targeting integrins.