Cyclophilin a knokdown inhibits cell migration and invasion through the suppression of epithelial-mesenchymal transition in colorectal cancer cells

PPIA enhances cell growth and metastasis through CD147 in oral cancer

Oral cancer is a malignant tumor, and the associated death rate has significantly increased over the past few decades. Secreted fractions are involved in various physiological processes, and their analysis has become a promising approach for discovering diagnostic and prognostic biomarkers for cancer detection and monitoring metastasis. Therefore, the discovery of potential prognostic, diagnostic, and therapeutic biomarkers for oral cancer metastasis is beneficial for developing effective strategies in oral cancer therapy. In this study, we used secretomic analysis to identify the secreted proteins involved in oral cancer. One of the identified proteins, peptidylprolyl isomerase A (PPIA), was selected for further investigation. We used RNA interference to investigate the effect of PPIA secretion on invasion and migration of OC3-I5 cells. Our results showed that reducing the expression and secretion of PPIA significantly decreased invasion and migration of OC3-I5 cells. Next, we used recombinant PPIA to investigate its direct effect on OC3 cell metastasis. The results revealed that proliferation, migration, and invasion of OC3 cells were significantly increased by treatment with the recombinant PPIA. Immunohistochemical analyses revealed higher PPIA expression in tumor tissues compared to normal tissues. Concisely, PPIA activated the ERK1/2 and p38 MAPK signaling pathways and enhanced cell proliferation and metastasis through CD147. In summary, PPIA may prove to be a novel target for oral cancer therapy as well as a prognostic marker.

Cyclophilin A knockdown inhibits the proliferation and metastatic ability of AGS gastric cancer stem cells by downregulating CD147/STAT3/AKT/ERK and epithelial‑mesenchymal transition

Gastric cancer stem cells (GCSCs) contribute to the challenging aspects of gastric cancer, such as progression, metastasis, treatment resistance and recurrence. Inhibitors targeting cyclophilin A (CypA) have shown potential in curtailing GCSC growth. Building upon this, the current study delved deeper into understanding the functional role of CypA in controlling the proliferation and metastatic capabilities of GCSCs, employing CypA‑specific small interfering RNA. The results revealed that knockdown of CypA led to significant suppression of the growth and tumorsphere‑forming capacity of GCSCs derived from AGS cells. This effect was mediated by arresting the cell cycle at the G0/G1 and S phases, and promoting apoptosis. Furthermore, silencing of CypA exerted inhibitory effects on the migration and invasion of AGS GCSCs by modulating the process of epithelial‑mesenchymal transition. Notably, the observed antiproliferative and antimetastatic effects of CypA knockdown were associated with the downregulation of critical regulators of gastric cancer stemness, such as CD44, CD133, aldehyde dehydrogenase 1 family member A1, NANOG, OCT4 and SOX2. This regulation occurred through inactivation of the CD147/STAT3/AKT/ERK signaling pathway. Additionally, CypA knockdown effectively curbed in vivo tumor growth of AGS GCSCs in a chorioallantoic membrane assay using chick embryos. These findings underscore the critical role of CypA in promoting the proliferation and metastasis of GCSCs, highlighting its potential as an effective therapeutic target for eradicating GCSCs and improving gastric cancer treatment outcomes.

CypA/TAF15/STAT5A/miR-514a-3p feedback loop drives ovarian cancer metastasis

Cyclophilin A (CypA) is a peptidyl-prolyl isomerase that participates in multiple cancer events, but the molecular mechanisms of abnormal expression and regulation of CypA in ovarian cancer (OC) have never been considered. This study identifies CypA as a key driver of epithelial-mesenchymal transition (EMT) in ovarian cancer and explores the mechanisms that underly this process. We show that CypA is upregulated in tissues and serum of ovarian cancer patients and that CypA overexpression correlates with poor prognosis. CypA facilitates tumor growth and metastasis in vivo in subcutaneous tumor xenograft and abdominal metastatic models, and in vitro studies suggest a mechanism, showing that CypA accelerates ovarian cancer cell epithelial-mesenchymal transition by activating a PI3K/AKT signaling pathway. Mechanistic studies showed that STAT5A binds pri-miR-514a-3p and inhibits its activity, whereas miR-514a-3p directly binds to the 3'-UTR of CypA to suppress its expression, resulting in STAT5A promoting the expression of CypA, forming the STAT5A/miR-514a-3p/CypA axis. Furthermore, immunoprecipitates and mass spectrometry analysis identifies a CypA interaction with TAF15 that stabilizes TAF15 by suppressing its proteasome degradation and promotes its entry into the nucleus. While STAT5A is positively regulated by TAF15. Our findings identify a novel feedback loop for CypA that drives EMT and ovarian tumor growth and metastasis via a TAF15/STAT5A/miR-514a-3p pathway in ovarian cancer and facilitates the release of CypA into the extracellular, which provides a promising therapeutic target for OC treatment and a diagnostic biomarker.

Cyclophilin J limits linear ubiquitin signaling and controls colorectal cancer progression

Exorbitant sustained inflammation is closely linked to inflammation-associated disorders, including cancer. The initiation of gastrointestinal cancers such as colorectal cancer is frequently accelerated by uncontrollable chronic inflammation which is triggered by excessive activation of nuclear factor kappa-B (NF-κB) signaling. Linear ubiquitin chains play an important role in activating canonical NF-κB pathway. The only known E3 complex, linear ubiquitin chain assembly complex is responsible for the synthesis of linear ubiquitin chains, thus leading to the activation of NF-κB axis and promoting the development of inflammation and inflammation-associated cancers. We report here cyclophilin J (CYPJ) which is a negative regulator of the linear ubiquitin chain assembly complex. The N terminus of CYPJ binds to the second Npl4 zinc finger (NZF) domain of HOIL-1-interacting protein and the ubiquitin-like domain of Shank-associated RH domain-interacting protein to disrupt the interaction between HOIL-1-interacting protein and Shank-associated RH domain-interacting protein and thus restrains linear ubiquitin chain synthesis and NF-κB activation. Cypj-deficient mice are highly susceptible to dextran sulfate sodium-induced colitis and dextran sulfate sodium plus azoxymethane-induced colon cancer. Moreover, CYPJ expression is induced by hypoxia. Patients with high expression of both CYPJ and hypoxia-inducible factor-1α have longer overall survival and progression-free survival. These results implicate CYPJ as an unexpected robust attenuator of inflammation-driven tumorigenesis that exerts its effects by controlling linear ubiquitin chain synthesis in NF-κB signal pathway.

Cyclophilin A: An Independent Prognostic Factor for Survival in Patients with Metastatic Colorectal Cancer Treated with Bevacizumab and Chemotherapy

Colorectal cancer (CRC) ranks as second most common cause of cancer-related deaths. The CRC management considerably improved in recent years, especially due to biological therapies such as bevacizumab. The lack of predictive or prognostic biomarkers remains one of the major disadvantages of using bevacizumab in the CRC management. We performed a prospective study to analyze the prognostic and predictive roles of three potential serum biomarkers (Cyclophilin A (CypA), copeptin and Tie2) investigated by ELISA in 56 patients with metastatic CRC undergoing bevacizumab and chemotherapy between May 2019 and September 2021 at baseline and after one and six months of therapy. We showed that low levels of CypA at baseline and after one month of treatment were associated with better overall survival (OS) (42 versus 24 months, p = 0.029 at baseline; 42 versus 25 months, p = 0.039 after one month). For copeptin and Tie2, Kaplan-Meier curves showed no correlation between these biomarkers and OS or progression-free survival. When adjusting for baseline and post-treatment factors, a multivariate Cox analysis showed that low values of CypA at baseline and after one month of treatment were independent prognostic factors for OS and correlated with a better prognosis in metastatic CRC patients.

Secreted cyclophilin A is non-genotoxic but acts as a tumor promoter

Chronic inflammation is associated with malignant transformation and creates the microenvironment for tumor progression. Cyclophilin A (CypA) is one of the major pro-inflammatory mediators that accumulates and persists in the site of inflammation in high doses over time. According to multiomics analyses of transformed cells, CypA is widely recognized as a pro-oncogenic factor. Vast experimental data define the functions of intracellular CypA in carcinogenesis, but findings on the role of its secreted form in tumor formation and progression are scarce. In the studies here, we exploit short-term in vitro and in vivo tests to directly evaluate the mutagenic, recombinogenic, and blastomogenic effects, as well as the promoter activity of recombinant human CypA (rhCypA), an analogue of secreted CypA. Our findings showed that rhCypA had no genotoxicity and, thus, was neither involved in nor influenced the initiation stage of carcinogenesis. At high doses, rhCypA could disrupt gap junctions in rat liver epithelial IAR-2 cells in vitro by decreasing the expression of connexins 26 and 43 in these cells and inhibit A549 cell adhesion. These data suggested that rhCypA could contribute to epithelial-mesenchymal transition in malignant cells. The research presented here elucidated the role of secreted CypA in carcinogenesis, revealing that it is not a tumor initiator but can act as a tumor promoter at high concentrations.

Cyclophilin A binds to AKT1 and facilitates the tumorigenicity of Epstein-Barr virus by mediating the activation of AKT/mTOR/NF-κB positive feedback loop

The AKT/mTOR and NF-κB signalings are crucial pathways activated in cancers including nasopharyngeal carcinoma (NPC), which is prevalent in southern China and closely related to Epstein-Barr virus (EBV) infection. How these master pathways are persistently activated in EBV-associated NPC remains to be investigated. Here we demonstrated that EBV-encoded latent membrane protein 1 (LMP1) promoted cyclophilin A (CYPA) expression through the activation of NF-κB. The depletion of CYPA suppressed cell proliferation and facilitated apoptosis. CYPA was able to bind to AKT1, thus activating AKT/mTOR/NF-κB signaling cascade. Moreover, the use of mTOR inhibitor, rapamycin, subverted the activation of the positive feedback loop, NF-κB/CYPA/AKT/mTOR. It is reasonable that LMP1 expression derived from initial viral infection is enough to assure the constant potentiation of AKT/mTOR and NF-κB signalings. This may partly explain the fact that EBV serves as a tumor-promoting factor with minimal expression of the viral oncoprotein LMP1 in malignancies. Our findings provide new insight into the understanding of causative role of EBV in tumorigenicity during latent infection.

A Novel Ex Vivo Approach Based on Proteomics and Biomarkers to Evaluate the Effects of Chrysene, MEHP, and PBDE-47 on Loggerhead Sea Turtles (Caretta caretta)

The principal aim of the present study was to develop and apply novel ex vivo tests as an alternative to cell cultures able to evaluate the possible effects of emerging and legacy contaminants in Caretta caretta. To this end, we performed ex vivo experiments on non-invasively collected whole-blood and skin-biopsy slices treated with chrysene, MEHP, or PBDE-47. Blood samples were tested by oxidative stress (TAS), immune system (respiratory burst, lysozyme, and complement system), and genotoxicity (ENA assay) biomarkers, and genotoxic and immune system effects were observed. Skin slices were analyzed by applying a 2D-PAGE/MS proteomic approach, and specific contaminant signatures were delineated on the skin proteomic profile. These reflect biochemical effects induced by each treatment and allowed to identify glutathione S-transferase P, peptidyl-prolyl cis-trans isomerase A, mimecan, and protein S100-A6 as potential biomarkers of the health-threatening impact the texted toxicants have on C. caretta. Obtained results confirm the suitability of the ex vivo system and indicate the potential risk the loggerhead sea turtle is undergoing in the natural environment. In conclusion, this work proved the relevance that the applied ex vivo models may have in testing the toxicity of other compounds and mixtures and in biomarker discovery.

Delicate regulation of IL-1β-mediated inflammation by cyclophilin A

The inflammatory response is tightly regulated, but its regulatory principles are still incompletely understood. Cyclophilin A (CypA) has long been considered as a pro-inflammatory factor. Here, we discover how CypA precisely regulates interleukin-1β (IL-1β)-mediated inflammatory responses. In lipopolysaccharide-treated mice, CypA deficiency initially inhibits and then promotes lung inflammation, which is closely related to IL-1β production. Mechanistically, CypA not only facilitates pro-IL-1β processing by increasing Smurf1-mediated K63-linked ubiquitination in an ATP-dependent manner but also accelerates pro-IL-1β degradation, depending on Smurf1-mediated K48-linked ubiquitination. Moreover, in IL-1β-treated mice, CypA exacerbates lung injury by enhancing cytokine production. It also upregulates the ILK/AKT pathway by inhibiting Cyld-mediated K63-linked ILK deubiquitination, which promotes the epithelial-mesenchymal transition (EMT) to facilitate lung repair. Collectively, CypA promotes inflammation activation by increasing IL-1β production and then promotes inflammation resolution by enhancing redundant pro-IL-1β degradation and IL-1β-induced EMT, indicating the complex and delicate regulation of inflammatory response.

The Role of Cyclophilins in Inflammatory Bowel Disease and Colorectal Cancer

Cyclophilins (Cyps) is a kind of ubiquitous protein family in organisms, which has biological functions such as promoting intracellular protein folding and participating in the pathological processes of inflammation and tumor. Inflammatory bowel disease (IBD) and colorectal cancer (CRC) are two common intestinal diseases, but the etiology and pathogenesis of these two diseases are still unclear. IBD and CRC are closely associated, IBD has always been considered as one of the main risks of CRC. However, the role of Cyps in these two related intestinal diseases is rarely studied and reported. In this review, the expression of CypA, CypB and CypD in IBD, especially ulcerative colitis (UC), and CRC, their relationship with the development of these two intestinal diseases, as well as the possible pathogenesis, were briefly summarized, so as to provide modest reference for clinical researches and treatments in future.