A Role for the Cavin-3/Matrix Metalloproteinase-9 Signaling Axis in the Regulation of PMA-Activated Human HT1080 Fibrosarcoma Cell Neoplastic Phenotype

Expression of the Cavin Family in Childhood Leukemia and Its Implications in Subtype Diagnosis and Prognosis Evaluation

BACKGROUND

Caveolae are plasma membrane subdomains of many mammalian cells that play critical roles in cellular processes, including endocytosis, signal transduction and tumorigenesis. Cavin proteins are essential for caveola formation, structure and function and are reported to be involved in various human diseases, but little is known about their expression and prognostic value in leukemia.

METHODS

We performed a detailed analysis of Cavin family mRNA expression levels in different cancer tissues vs. normal tissues via the ONCOMINE, Gene Expression Profiling Interactive Analysis (GEPIA) and Cancer Cell Line Encyclopedia (CCLE) databases. Then, we used qRT-PCR and Western blotting to validate Cavin1-4 expression in 10 fresh leukemia samples. Moreover, we estimated their prognostic value in leukemia with the R programming language and GEPIA database.

RESULTS

The expression of Cavin members is low in most human cancers, especially in leukemia. Cavin-1 and Cavin-2 are often more expressed in myeloid leukemia than lymphoblastic leukemia, but Cavin-4 has the opposite pattern. Interestingly, low expression of CAVIN1 and CAVIN4 is correlated with poorer outcome but low CAVIN2 expression is associated with a significantly better leukemia prognosis in leukemia.

CONCLUSION

The Cavin family showed significant expression differences between leukemia and normal cells. High Cavin-2 and low Cavin-4 levels predict poor survival and could be promising subtype diagnosis and prognosis biomarkers for leukemia.

Cavin3 released from caveolae interacts with BRCA1 to regulate the cellular stress response

Caveolae-associated protein 3 (cavin3) is inactivated in most cancers. We characterized how cavin3 affects the cellular proteome using genome-edited cells together with label-free quantitative proteomics. These studies revealed a prominent role for cavin3 in DNA repair, with BRCA1 and BRCA1 A-complex components being downregulated on cavin3 deletion. Cellular and cell-free expression assays revealed a direct interaction between BRCA1 and cavin3 that occurs when cavin3 is released from caveolae that are disassembled in response to UV and mechanical stress. Overexpression and RNAi-depletion revealed that cavin3 sensitized various cancer cells to UV-induced apoptosis. Supporting a role in DNA repair, cavin3-deficient cells were sensitive to PARP inhibition, where concomitant depletion of 53BP1 restored BRCA1-dependent sensitivity to PARP inhibition. We conclude that cavin3 functions together with BRCA1 in multiple cancer-related pathways. The loss of cavin3 function may provide tumor cell survival by attenuating apoptotic sensitivity and hindering DNA repair under chronic stress conditions.

Prognostic and diagnostic significance of Cavin 2 in lung adenocarcinoma

INTRODUCTION

Cavin 2 down-regulation is reported in several malignant tumors and is associated with tumor progression. However, the role of Cavin 2 in lung adenocarcinoma is unknown. This study aimed to investigate the prognostic and diagnostic significance of Cavin 2 in lung adenocarcinoma.

MATERIAL AND METHODS

Cavin 2 expression levels were examined in 150 cases of lung adenocarcinoma and matched adjacent normal lung tissues using RNA extraction and reverse transcription-quantitative polymerase chain reaction (RT-qPCR), Western blotting and immunohistochemistry (IHC) assays. Then, the relationship of Cavin 2 expression with clinicopathological characteristics and patients' survival was further evaluated in lung adenocarcinoma.

RESULTS

QPCR and Western blotting analysis indicated that Cavin 2 expression levels were significantly lower in lung adenocarcinoma tissues compared with those in adjacent normal lung tissues (p < 0.0001). The IHC results showed that positive expression of Cavin 2 was mainly located in cytoplasm as brown, but was hard to detect in lung adenocarcinoma tissues. The low-expression rates of Cavin 2 in lung adenocarcinoma and adjacent normal lung tissues were 62.0% and 20.0%, respectively, and the difference was significant (p < 0.0001). Lower expression of Cavin 2 was significantly associated with tumor size, TNM stage and lymph node metastasis (p < 0.05).

CONCLUSIONS

Cavin 2 has low expression in lung adenocarcinoma, which might be regarded as a potential prognostic and diagnostic biomarker.

Indole‑6‑carboxaldehyde isolated from Sargassum thunbergii inhibits the expression and secretion of matrix metalloproteinase‑9

Sargassum thunbergii is a brown alga from which various bioactive compounds can be extracted. Among these, the activities of indole derivatives, particularly as potential inhibitors of matrix metalloproteinases (MMPs), and their underlying mechanisms have been rarely investigated. Therefore, we evaluated the inhibitory effects of indole‑6‑carboxaldehyde (I6CA) on MMP‑9 by gelatin zymography and western blot anlaysis. We used phorbol 12‑myristate 13‑acetate (PMA), which is known to induce MMP‑9 expression and secretion, to stimulate HT1080 cells. Our results revealed that I6CA significantly inhibited MMP‑9 expression and secretion, without significantly affecting the viability of PMA‑stimulated HT1080 cells. Our mechanistic studies indicated that I6CA suppressed the phosphorylation and activation of two mitogen‑activated protein kinases (MAPKs), c‑Jun N‑terminal kinase (JNK) and extracellular signal‑regulated kinase 1/2 (ERK). Furthermore, I6CA inhibited the phosphorylation of inhibitor of κBα (IκBα) in response to PMA stimulation, which suppressed nuclear factor‑κB (NF‑κB) p65 subunit nuclear translocation. Collectively, I6CA was determined to suppress MMP‑9 expression and secretion, and effects were proposed to be mediated via the inhibition of the MAPK and NF‑κB p65 pathways. Therefore, we suggested I6CA to be a potential therapeutic agent for MMP‑9‑related processes, including tumor invasion and metastasis; however, further investigation is required.

A Transcriptional Regulatory Role for the Membrane Type-1 Matrix Metalloproteinase in Carcinogen-Induced Inflammasome Gene Expression

Signal-transducing functions driven by the cytoplasmic domain of membrane type-1 matrix metalloproteinase (MT1-MMP) are believed to regulate many inflammation-associated cancer cell functions including migration, proliferation, and survival. Aside from upregulation of the inflammation biomarker cyclooxygenase-2 (COX-2) expression, MT1-MMP’s role in relaying intracellular signals triggered by extracellular pro-inflammatory cues remains poorly understood. Here, we triggered inflammation in HT1080 fibrosarcoma cells with phorbol-12-myristate-13-acetate (PMA), an inducer of COX-2 and of MT1-MMP. To assess the global transcriptional regulatory role that MT1-MMP may exert on inflammation biomarkers, we combined gene array screens with a transient MT1-MMP gene silencing strategy. Expression of MT1-MMP was found to exert both stimulatory and repressive transcriptional control of several inflammasome-related biomarkers such as interleukin (IL)-1B, IL-6, IL-12A, and IL-33, as well as of transcription factors such as EGR1, ELK1, and ETS1/2 in PMA-treated cells. Among the signal-transducing pathways explored, the silencing of MT1-MMP prevented PMA from phosphorylating extracellular signal–regulated kinase, inhibitor of κB, and p105 nuclear factor κB (NF-κB) intermediates. We also found a signaling axis linking MT1-MMP to MMP-9 transcriptional regulation. Altogether, our data indicate a significant involvement of MT1-MMP in the transcriptional regulation of inflammatory biomarkers consolidating its contribution to signal transduction functions in addition to its classical hydrolytic activity.

Cavin-2 Functions as a Suppressive Regulator in TNF-induced Mesenchymal Stromal Cell Inflammation and Angiogenic Phenotypes

Tumour necrosis factor (TNF)-α activation of mesenchymal stromal cells (MSC) enhances their tumour-suppressive properties and tumour-homing ability. The molecular actors involved are unknown. We found that TNF induced MSC migration and tubulogenesis which correlated with a dose-dependent increase in Cavin-1 and Cavin-3 transcript levels. TNF triggered cyclooxygenase (COX)-2 expression, whereas specific siRNA-mediated gene silencing of Cavin-2 resulted in an amplified COX-2 expression, tubulogenesis, and migratory response partially due to a rapid and sustained increase in NF-κB phosphorylation status. Our results highlight a suppressive role for the caveolar component Cavin-2 in the angiogenic and inflammatory regulation of TNF-activated MSC.

Human amniotic mesenchymal stem cells alleviate lung injury induced by ischemia and reperfusion after cardiopulmonary bypass in dogs

Transplantation of mesenchymal stem cells may inhibit pathological immune processes contributing to ischemia/reperfusion (I/R) injury. This study aimed to assess the capacity of human amniotic MSC (hAMSCs) to ameliorate I/R injury in a dog model of cardiopulmonary bypass (CPB). Dissociated hAMSCs were cultured ex vivo, and their immunophenotypes were assessed by flow cytometry and immunohistochemistry. A dog model of CPB was established by surgical blockage of the aorta for 1 h. Dogs either underwent mock surgery (Sham group), CPB (model group), or CPB, followed by femoral injection of 2 × 10(7) hAMSCs (n=6). Anti-human nuclei staining revealed hAMSCs in the lungs 3 h after surgery. Oxygen index (OI) and respiratory index (RI) of arterial blood were measured using a biochemical analyzer. Venous blood TNF-α, IL-8, MMP-9, and IL-10 concentrations were measured by ELISA. Pathological changes in the lung were assessed by light microscopy. Third-generation-cultured hAMSCs expressed high levels of CD29, CD44, CD49D, CD73, and CD166 levels, but low CD34 or CD45 amounts and their cytoplasm contained Vimentin. In CPB model animals, OI was elevated and RI reduced; TNF-α, IL-8, and MMP-9 levels were elevated, and IL-10 levels reduced within 3h (P<0.05), but hAMSC transplantation significantly ameliorated these changes (P<0.05). Pathological changes observed in the hAMSC group were significantly less severe than those in the CPB group. In conclusion, hAMSC transplantation can downregulate proinflammatory factors and reduce MMP-9 levels, whereas upregulating the anti-inflammatory molecule IL-10, thus reducing I/R lung injury in a dog model of CPB.