The peptide mimicking small extracellular loop domain of CD82 inhibits tumor cell migration, adhesion and induces apoptosis by inhibiting integrin mediated signaling

The role of Tetraspanins in digestive system tumor development: update and emerging evidence

Digestive system malignancies, including cancers of the esophagus, pancreas, stomach, liver, and colorectum, are the leading causes of cancer-related deaths worldwide due to their high morbidity and poor prognosis. The lack of effective early diagnosis methods is a significant factor contributing to the poor prognosis for these malignancies. Tetraspanins (Tspans) are a superfamily of 4-transmembrane proteins (TM4SF), classified as low-molecular-weight glycoproteins, with 33 Tspan family members identified in humans to date. They interact with other membrane proteins or TM4SF members to form a functional platform on the cytoplasmic membrane called Tspan-enriched microdomain and serve multiple functions including cell adhesion, migration, propagation and signal transduction. In this review, we summarize the various roles of Tspans in the progression of digestive system tumors and the underlying molecular mechanisms in recent years. Generally, the expression of CD9, CD151, Tspan1, Tspan5, Tspan8, Tspan12, Tspan15, and Tspan31 are upregulated, facilitating the migration and invasion of digestive system cancer cells. Conversely, Tspan7, CD82, CD63, Tspan7, and Tspan9 are downregulated, suppressing digestive system tumor cell metastasis. Furthermore, the connection between Tspans and the metastasis of malignant bone tumors is reviewed. We also summarize the potential role of Tspans as novel immunotherapy targets and as an approach to overcome drug resistance. Finally, we discuss the potential clinical value and therapeutic targets of Tspans in the treatments of digestive system malignancies and provide some guidance for future research.

Tetraspanin CD82 restrains phagocyte migration but supports macrophage activation

Phagocytes migrate into tissues to combat infection and maintain tissue homeostasis. As dysregulated phagocyte migration and function can lead to inflammation or susceptibility to infection, identifying molecules that control these processes is critical. Here, we show that the tetraspanin CD82 restrains the migration of neutrophils and macrophages into tissues. Cd82^−/− phagocytes exhibited excessive migration during in vivo models of peritoneal inflammation, superfusion of CXCL1, retinopathy of prematurity, and infection with the protozoan parasite L. mexicana. However, with the latter, while Cd82^−/− macrophages infiltrated infection sites at higher proportions, cutaneous L. mexicana lesions were larger and persisted, indicating a failure to control infection. Analyses of in vitro bone-marrow-derived macrophages showed CD82 deficiency altered cellular morphology, and impaired gene expression and metabolism in response to anti-inflammatory activation. Altogether, this work reveals an important role for CD82 in restraining phagocyte infiltration and mediating their differentiation in response to stimulatory cues.

•

Tetraspanin CD82 restrains phagocyte migration in murine models of inflammation

•

Excessive migration of Cd82^−/− myeloid cells exacerbates retinal inflammation

•

Cd82^−/− macrophages have a reduced ability to clear Leishmania mexicana parasites

•

CD82 is required for the normal morphology and activation of M2 macrophages

Theragnostic strategies harnessing the self-renewal pathways of stem-like cells in the acute myeloid leukemia

Acute myelogenous leukemia (AML) is a genetically heterogeneous and aggressive cancer of the Hematopoietic Stem/progenitor cells. It is distinguished by the uncontrollable clonal growth of malignant myeloid stem cells in the bone marrow, venous blood, and other body tissues. AML is the most predominant of leukemias occurring in adults (25%) and children (15-20%). The relapse after chemotherapy is a major concern in the treatment of AML. The overall 5-year survival rate in young AML patients is about 40-45% whereas in the elderly patients it is less than 10%. Leukemia stem-like cells (LSCs) having the ability to self-renew indefinitely, repopulate and persist longer in the G0/G1 phase play a crucial role in the AML relapse and refractoriness to chemotherapy. Hence, novel treatment strategies and diagnostic biomarkers targeting LSCs are being increasingly investigated. Through this review, we have explored the signaling modulations in the LSCs as the theragnostic targets. The significance of the self-renewal pathways in overcoming the treatment challenges in AML has been highlighted.

Tetraspanin 7 promotes osteosarcoma cell invasion and metastasis by inducing EMT and activating the FAK-Src-Ras-ERK1/2 signaling pathway

Background

Tetraspanins are members of the 4-transmembrane protein superfamily (TM4SF) that function by recruiting many cell surface receptors and signaling proteins into tetraspanin-enriched microdomains (TEMs) that play vital roles in the regulation of key cellular processes including adhesion, motility, and proliferation. Tetraspanin7 (Tspan7) is a member of this superfamily that plays documented roles in hippocampal neurogenesis, synaptic transmission, and malignant transformation in certain tumor types. How Tspan7 influences the onset or progression of osteosarcoma (OS), however, remains to be defined. Herein, this study aimed to explore the relationship between Tspan7 and the malignant progression of OS, and its underlying mechanism of action.

Methods

In this study, the levels of Tspan7 expression in human OS cell lines were evaluated via qRT-PCR and western blotting. The effect of Tspan7 on proliferation was examined using CCK-8 and colony formation assays, while metastatic role of Tspan7 was assessed by functional assays both in vitro and in vivo. In addition, mass spectrometry and co-immunoprecipitation were performed to verify the interaction between Tspan7 and β1 integrin, and western blotting was used to explore the mechanisms of Tspan7 in OS progresses.

Results

We found that Tspan7 is highly expressed in primary OS tumors and OS cell lines. Downregulation of Tspan7 significantly suppressed OS growth, metastasis, and attenuated epithelial-mesenchymal transition (EMT), while its overexpression had the opposite effects in vitro. Furthermore, it exhibited reduced OS pulmonary metastases in Tspan7-deleted mice comparing control mice in vivo. Additionally, we proved that Tspan7 interacted with β1 integrin to facilitate OS metastasis through the activation of integrin-mediated downstream FAK-Src-Ras-ERK1/2 signaling pathway.

Conclusion

In summary, this study demonstrates for the first time that Tspan7 promotes OS metastasis via interacting with β1 integrin and activating the FAK-Src-Ras-ERK1/2 pathway, which could provide rationale for a new therapeutic strategy for OS.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-022-02591-1.

Small extracellular ring domain is necessary for CD82/KAI1'anti-metastasis function

The peptide mimicking small extracellular loop of CD82/KAI1 has been reported to inhibit tumor cell migration and metastasis. This provides an evidence that small extracellular loop domain should be important for the function of CD82/KAI1. In this paper, to investigate the structure basis for the function of EC1 mimic peptide, we systematically analyzed the effects of each amino acid residue in EC1 mimic peptide on its bioactivity. We found that the interfering with the folding of secondary structure with proline, a potent breaker of secondary structure, completely abolished the migration and metastasis-inhibitory activity of EC1 mimic peptide. This means that the bioactivity of EC1 mimic peptide was conformation-dependent. Next, we substitute with proline for amino acid residues in the small extracellular ring region of CD82/KAI1 by the site-specific mutations to disrupting secondary structure and detected its effect on the function of CD82/KAI1. The results showed that the disturbing the secondary structure of small extracellular ring completely abolished the migration and metastasis-inhibitory activity of CD82/KAI1. These results further provide direct evidence that the small extracellular ring is an important function region of CD82/KAI1.

The peptide mimicking small extracellular ring domain of CD82 inhibits tumor cell migration in vitro and metastasis in vivo

BACKGROUND

Tetraspanin KAI1/CD82, a tumor metastasis suppressor, has emerged as a promising molecular target for the management of metastatic disease. However, the peptide mimicking small extracellular ring domain (EC1) of CD82 has not been fully investigated for the function of inhibiting cell migration in vitro and tumor metastasis in vivo.

METHODS

Different cancer cells were treated with EC1 mimic peptide in order to detect migration and invasion by the healing assay and transwell. Cell aggregation and adhesion assays were used to investigate the function of homotypic cell-cell aggregation and adhesion to tissue culture plates. Then, we established syngeneic and xenograft animal models to assess the metastasis inhibitory effect of EC1 mimic peptide in vivo.

RESULTS

In vitro studies, the EC1 mimic peptide had been showed to promote homotypic cell-cell aggregation, suppress cell migration, invasion and adherence in multiple tumor cell types. In vivo metastasis assays, the EC1 mimic peptide could strongly inhibit the pulmonary metastasis of LCC in syngeneic mice model and SW620 and H1299 in xenograft mice model.

CONCLUSION

This novel finding will improve our understanding of the mechanism by which CD82 inhibits metastasis, and suggests that EC1 mimic peptide may be a promising candidate for developing anti-metastasis drugs.

CD82 supports survival of childhood acute myeloid leukemia cells via activation of Wnt/β-catenin signaling pathway

BACKGROUND

Stem cell marker CD82 plays a vital role in the oncogenesis and progression of acute myelogenous leukemia (AML), especially in sharing properties of leukemia stem cells (LSCs). The Wnt/β-catenin pathway is required for the development of LSCs in AML. The present study aimed to validate whether CD82 supports the survival of LSCs in pediatric AML via activation of Wnt/β-catenin signaling pathway.

METHODS

CD82 expression and its correlation with molecules downstream of Wnt/β-catenin pathway in samples from pediatric AML patients were analyzed. Forced or downregulated expression of CD82 in AML cells was evaluated for the effects of CD82 on cell proliferation, cycle regulation, apoptosis, and adriamycin chemoresistance and to validate the underlying mechanism.

RESULT

Aberrant expression of CD82 in pediatric AML patients was found. CD82 messenger RNA expression correlated positively with downstream molecules of Wnt/β-catenin pathway in AML children. Knockdown of CD82 induced apoptosis, suppressed growth, and decreased adriamycin chemoresistance in AML cells. CD82 accelerated β-catenin nuclear location and then stimulated the expression of downstream molecules of Wnt/β-catenin pathway.

CONCLUSION

CD82 regulates the proliferation and chemotherapy resistance of AML cells via activation of the Wnt/β-catenin pathway, which suggest that the CD82 may be a potential therapeutic target in AML children.