IKBIP promotes tumor development via the akt signaling pathway in esophageal squamous cell carcinoma.

BACKGROUND: Esophageal squamous cell carcinoma (ESCC) is one of the most common cancers worldwide. Inhibitor of kappa B kinase interacting protein (IKBIP) has been reported to promote glioma progression, but its role in other cancers remains unclear. This study aimed to investigate the role of IKBIP and its underlying molecular mechanisms in ESCC. METHODS: The mRNA expression of IKBIP was analyzed using multiple cancer databases. Immunohistochemistry was performed to detect IKBIP protein expression in ESCC tissues and adjacent normal tissues, and Kaplan‒Meier survival and Cox regression analyses were carried out. The effects of IKBIP knockdown (or overexpression) on ESCC cells were detected by cell viability, cell migration, flow cytometry and Western blot assays. LY-294002 was used to validate the activation of the AKT signaling pathway by IKBIP. Finally, the role of IKBIP in ESCC was verified in a xenograft model. RESULTS: Both bioinformatics analysis and immunohistochemistry indicated that IKBIP expression in ESCC tissues was significantly increased and was associated with the prognosis of ESCC patients. In vitro experiments revealed that IKBIP knockdown significantly inhibited the proliferation and migration of ESCC cells, and induced cell apoptosis and G1/S phase arrest. Molecular mechanism results showed that the AKT signaling pathway was further activated after IKBIP overexpression, thereby increasing the proliferation and migration abilities of ESCC cells. In vivo study confirmed that IKBIP promoted the initiation and development of ESCC tumors in mice. CONCLUSIONS: IKBIP plays a tumor-promoting role in ESCC and may serve as a predictive biomarker and a potential therapeutic target for ESCC.

PFKP confers chemoresistance by upregulating ABCC2 transporter in non-small cell lung cancer.

Background: Chemoresistance is a significant factor contributing to tumor recurrence and treatment failure in non-small cell lung cancer (NSCLC). The phosphofructokinase, platelet (PFKP) is highly expressed in NSCLC and is associated with a poor prognosis. Exploring the molecular mechanism and identifying effective strategies to overcome chemoresistance will have important clinical significance in improving the diagnosis and treatment of NSCLC. Methods: The correlation between PFKP and cisplatin resistance in NSCLC patients was assessed by organoids and immunohistochemistry. The impact of PFKP on the prognosis of NSCLC patients was analyzed using The Cancer Genome Atlas (TCGA) database. In NSCLC cell lines, the expression of PFKP was modulated using lentivirus, and cisplatin sensitivity was assessed by flow cytometry. Subsequently, the therapeutic effect of cisplatin was tested in BALB/c nude mice implanted subcutaneously with tumor cells. We performed luciferase assay and immunohistochemistry (IHC) to investigate the correlation between PFKP and ABCC2 (ATP-binding cassette sub-family C member 2). Results: Overexpression of PFKP was correlated with poorer survival rates in NSCLC patients who received platinum-based chemotherapy. Using NSCLC organoid, we found that the expression of PFKP was elevated in cisplatin (CDDP)-resistant patients with NSCLC. Overexpression of PFKP decreased the sensitivity of NSCLC cells to CDDP, while genetic inhibition of PFKP enhanced CDDP sensitivity both in vitro and in vivo. Furthermore, we found that PFKP upregulated ABCC2 by increasing the levels of phosphorylation of IκBα and nuclear p65 NF-κB subunit protein. Conclusions: PFKP can regulate the expression of ABCC2 through the activation of NF-κB, which in turn promotes chemoresistance in NSCLC. PFKP has the potential to be a personalized therapeutic target for NSCLC patients with chemoresistance.

KDF1 Promoted Proliferation, Migration and Invasion of Lung Adenocarcinoma Cells through Activating STAT3 and AKT Pathway.

KDF1 has been reported to be correlated with carcinogenesis. However, its role and mechanism are far from clear. To explore the possible role and underlying mechanism of KDF1 in lung adenocarcinoma (LUAD), we investigated KDF1 expression in LUAD tissues and the influence of KDF1 in the phenotype of LUAD cells (A549 and PC-9) as well as the underlying mechanism. Compared to non-tumor lung epithelial cells, KDF1 was upregulated in the cancer cells of the majority of LUAD patients, and its expression was correlated with tumor size. Patients with enhanced KDF1 in cancer cells (compared with paired adjacent non-neoplastic lung epithelial cells) had shorter overall survival than patients with no increased KDF1 in cancer cells. Knockdown of KDF1 inhibited the migration, proliferation and invasion of LUAD cells in vitro. And overexpression of KDF1 increased the growth of the subcutaneous tumors in mice. In terms of molecular mechanisms, overexpression of KDF1 induced the expression of AKT, p-AKT and p-STAT3. In KDF1-overexpressing A549 cells, inhibition of the STAT3 pathway decreased the level of AKT and p-AKT, whereas inhibition of the AKT pathway had no effect on the activation of STAT3. Inhibition of STAT3 or AKT pathways reversed the promoting effects of KDF1 overexpression on the LUAD cell phenotype and STAT3 inhibition appeared to have a better effect. Finally, in the cancer cells of LUAD tumor samples, the KDF1 level was observed to correlate positively with the level of p-STAT3. All these findings suggest that KDF1, which activates STAT3 and the downstream AKT pathway in LUAD, acts as a tumor-promoting factor and may represent a therapeutic target.

Integrin α6 overexpression promotes lymphangiogenesis and lymphatic metastasis via activating the NF-κB signaling pathway in lung adenocarcinoma.

OBJECTIVE: It has been reported that tumor-associated lymphangiogenesis plays an important role in lymph node metastasis and contributes to the poor survival of lung adenocarcinoma (LUAD) patients. As yet, however, the molecular mechanism underlying LUAD-associated lymphangiogenesis has remained elusive. METHODS: Immunohistochemistry (IHC) was used to determine the expression of integrin subunit alpha 6 (ITGA6) and the lymphatic vessel endothelial hyaluronan receptor 1 (Lyve1) in clinicopathologically characterized LUAD specimens. The effect of ITGA6 overexpression on lymphangiogenesis and lymphatic metastasis was examined by tube formation, scratch wound-healing, and cell migration assays in vitro and a popliteal lymph node metastasis model in vivo. Mechanistically, overexpression of ITGA6 and activation of NF-κB signaling were examined by real-time PCR, ubiquitination and dual-luciferase reporter assays. Finally, high ITGA6 expression in LUAD tissue samples was related to copy number variation (CNV) using the TCGA database. RESULTS: We found that ITGA6 overexpression correlated with microlymphatic vessel density in LUAD specimens (p < 0.01). Importantly, by using a popliteal lymph node metastasis model, we found that ITGA6 upregulation significantly enhanced lymphangiogenesis and lymphatic metastasis in vivo (p < 0.05). In addition, we found that ITGA6 overexpression enhanced the capability of A549 and H1299 LUAD cells to induce tube formation and migration in human lymphatic endothelial cells (HLECs). Mechanistically, we found that ITGA6 sustained NF-κB activity via binding and promoting K63 polyubiquitination of TNF receptor-associated factor 2 (TRAF2). Finally, CNV analysis revealed ITGA6 amplification of 27.5% in the LUAD tissue samples in the TCGA database. CONCLUSIONS: Taken together, our results uncover a plausible role for ITGA6 in mediating lymphangiogenesis and lymphatic metastasis and may provide a basis for targeting ITGA6 to treat LUAD lymphatic metastasis.

By Increasing the Expression and Activation of STAT3, Sustained C5a Stimulation Increases the Proliferation, Migration, and Invasion of RCC Cells and Promotes the Growth of Transgrafted Tumors.

BACKGROUND: Contradictive results about the direct role of C5a/C5aR1 axis in different cancer cells have been reported. The direct effect of C5a on human renal cell carcinoma (RCC) cells and the underlying mechanism are not clear. The aim of this study is to investigate the role of C5a/C5aR1 axis in RCC cells and its working mechanism. METHODS: RCC cells were infected with lentivirus Lenti-C5a, which was designed to over-express secretory C5a in the cells, or directly treated with recombinant C5a, the influence of these treatments in the cells and the underlying mechanism were explored. RESULTS: Transfection of RCC cells with Lenti-C5a markedly increased the production of C5a and significantly increased the proliferation, migration, and invasion of RCC cells, but direct addition of C5a to the cell culture medium had no such effects though it indeed induced a transient intracellular calcium rise. RCC cells were found to express carboxypeptidase D and M, which reportedly to inactivate C5a. Also, the RCC cells stably transfected with Lenti-C5a produced larger transgrafted tumors in nude mice compared with the non-transfected or control virus transfected cells. In addition, over-expression of C5a significantly increased the expression and phosphorylation of STAT3 as well as the phosphorylated JNK level. Furthermore, the effect of C5a over-expression on RCC cells' proliferation, migration, and invasion could be blocked by Stattic, a STAT3-specific inhibitor. CONCLUSION: Chronic over-activation of C5a/C5aR1 axis could directly increase RCC cells' proliferation, migration, and invasion and thus contribute directly to the progression of the disease. Over-activation of STAT3 pathway is among the underlying mechanism.

KDF1, a Novel Tumor Suppressor in Clear Cell Renal Cell Carcinoma.

KDF1 has been identified as a key regulator of epidermal proliferation and differentiation, but it is unknown whether KDF1 is involved in the pathogenesis of malignancy. No study has reported the expression and function of KDF1 in renal cancer. To explore the pathologic significance of KDF1 in clear cell renal cell carcinoma (ccRCC), the expression level of KDF1 protein in the tumor tissue of ccRCC patients was examined by immunohistochemistry and Western blot while the expression level of KDF1 mRNA was analyzed by using the data from TCGA database. In vitro cell experiments and allogeneic tumor transplantation tests were performed to determine the effects of altered KDF1 expression on the phenotype of ccRCC cells. Both the KDF1 mRNA and protein were found to be decreasingly expressed in the tumor tissue of ccRCC patients when compared with the adjacent non-tumor control tissue. The expression level of KDF1 in the tumor tissue was found to correlate negatively with the tumor grade. Patients with higher KDF1 in the tumor tissue were found to have longer overall survival and disease-specific survival time. KDF1 was shown to be an independent factor influencing the disease-specific survival of the ccRCC patients. Overexpression of KDF1 was found to inhibit the proliferation, migration and invasion of ccRCC cells, which could be reversed by decreasing the expression of KDF1 again. ccRCC cells with KDF1 overexpression were found to produce smaller transgrafted tumors. These results support the idea that KDF1 is involved in ccRCC and may function as a tumor suppressor.

Study of a laser echo in an inhomogeneous dust environment with a continuous field Monte Carlo radiative transfer model.

A continuous field Monte Carlo radiative transfer model with an improved semianalytic approach is developed to study laser propagation in an inhomogeneous dust environment. In the proposed model, the photon step size can vary with the mass concentration of the dust environment. Additionally, the scattering properties of the dust particles are calculated with the T-matrix method and the T-matrix scattering phase function is applied to the Monte Carlo simulation with a rejection method. Using this model, the influences of the particle sizes and shapes on the backscattering properties are studied. Finally, the laser echoes simulated by our proposed model are compared with those of traditional Monte Carlo method and experimental results. Different mass concentration distributions indeed influence the simulated laser echo. The simulated results (of our proposed model) agree well with the measured data, demonstrating the effectiveness and accuracy of our approach for inhomogeneous media.

Competition between PAF1 and MLL1/COMPASS confers the opposing function of LEDGF/p75 in HIV latency and proviral reactivation.

Transcriptional status determines the HIV replicative state in infected patients. However, the transcriptional mechanisms for proviral replication control remain unclear. In this study, we show that, apart from its function in HIV integration, LEDGF/p75 differentially regulates HIV transcription in latency and proviral reactivation. During latency, LEDGF/p75 suppresses proviral transcription via promoter-proximal pausing of RNA polymerase II (Pol II) by recruiting PAF1 complex to the provirus. Following latency reversal, MLL1 complex competitively displaces PAF1 from the provirus through casein kinase II (CKII)-dependent association with LEDGF/p75. Depleting or pharmacologically inhibiting CKII prevents PAF1 dissociation and abrogates the recruitment of both MLL1 and Super Elongation Complex (SEC) to the provirus, thereby impairing transcriptional reactivation for latency reversal. These findings, therefore, provide a mechanistic understanding of how LEDGF/p75 coordinates its distinct regulatory functions at different stages of the post-integrated HIV life cycles. Targeting these mechanisms may have a therapeutic potential to eradicate HIV infection.