Impact of time to first relapse on long-term outcome in adult retroperitoneal sarcoma patients after radical resection.

BACKGROUND: Local recurrence of primary retroperitoneal sarcoma (RPS) is one of the major causes of treatment failure and death. We attempted to assess the effects of time to local recurrence (TLR) on the survival after recurrence (SAR) and overall survival (OS) of RPS. METHODS: Included in this study were 224 patients who underwent R0 resection for primary RPS at our institution between January 2000 and December 2020, 118 of whom had local recurrence. Based on the median TLR (19.8 months), patients were divided into two groups: early local recurrence (ELR < 20 months) and late local recurrence (LLR > 20 months). The Kaplan-Meier method was employed to calculate the local recurrence-free survival (LRFS), SAR and OS. Univariate and multivariate analyses were conducted to explore the prognostic value of TLR. RESULTS: The median follow-up time was 60.5 months for the entire cohort and 58.5 months for the recurrence cohort. There were 60 (50.8%) patients in the ELR group and 58 (49.2%) in the LLR group. The ELR group exhibited a worse SAR (29.2 months vs. 73.4 months, P < 0.001), OS (41.8 months vs. 120.9 months, P < 0.001), and a lower 5-year OS rate (35.9% vs. 73.2%, P = 0.004) than the LLR group. Furthermore, multivariate analysis indicated that TLR was an independent prognostic indicator for SAR (P = 0.014) and OS (P < 0.001). CONCLUSIONS: In patients with RPS, ELR after R0 resection presents adverse effects on OS and SAR than those with LLR, and TLR could serve as a promising predictor for OS and SAR.

Toxicological profile and safety pharmacology of a single dose of fibroblast activation protein-α-based doxorubicin prodrug: in-vitro and in-vivo evaluation.

Fibroblast activation protein-α (FAPα) is a promising tumor-associated target expressed by reactive stromal fibroblasts in tumor tissue. FAPα has a postprolyl peptidase activity and can specifically cleave N-terminal benzyloxycarbonyl (Z)-blocked peptides, such as the substrate Z-Gly-Pro-AMC. Doxorubicin (DOX) is an effective antitumor drug, but its application is greatly limited by toxic adverse effects owing to poor tumor selectivity. Based on these facts, we previously designed a FAPα-targeting prodrug of doxorubicin (FTPD) which can be selectively hydrolyzed by FAPα. FTPD can retain potent antitumor efficacy and has favorable tumor targeting. The present study aimed to further evaluate the toxicological profile and the safety pharmacological property of FTPD in vitro and in vivo. The cytotoxicity assay showed that FTPD displayed markedly lower cytotoxicity to 3T3 cells and HEK-293 cells compared with DOX. In the short-term toxicity study, mice treated with 25 mg/kg of FTPD showed no obvious change in the appearance and general behavior, and no case of mortality was observed within 14 days. Unlike DOX, FTPD exhibited reduced toxicity to heart, liver, kidney, spleen as well as peripheral white blood cells in mice. Moreover, open file test and general pharmacology study were also conducted correspondingly in mice and beagle dogs. It was found that FTPD may not produce significant pharmacological effects on spontaneous locomotor activity and cardiovascular-respiratory system except for a transient decreasing in systolic blood pressure. Taken together, the results of this work suggest that FTPD has more favorable toxicological profile and better drug safety compared with its parent drug DOX.

The TGF-ß-induced up-regulation of NKG2DLs requires AKT/GSK-3ß-mediated stabilization of SP1.

Natural killer (NK) cells play an important role in preventing cancer development. NK group 2 member D (NKG2D) is an activating receptor expressed in the membrane of NK cells. Tumour cells expressing NKG2DL become susceptible to an immune-dependent rejection mainly mediated by NK cells. The paradoxical roles of transforming growth factor beta (TGF-ß) in regulation of NKG2DL are presented in many studies, but the mechanism is unclear. In this study, we showed that TGF-ß up-regulated the expression of NKG2DLs in both PC3 and HepG2 cells. The up-regulation of NKG2DLs was characterized by increasing the expression of UL16-binding proteins (ULBPs) 1 and 2. TGF-ß treatment also increased the expression of transcription factor SP1. Knockdown of SP1 significantly attenuated TGF-ß-induced up-regulation of NKG2DLs in PC3 and HepG2 cells, suggesting that SP1 plays a key role in TGF-ß-induced up-regulation of NKG2DLs. TGF-ß treatment rapidly increased SP1 protein expression while not mRNA level. It might be due to that TGF-ß can elevate SP1 stability by activating PI3K/AKT signalling pathway, subsequently inhibiting GSK-3ß activity and decreasing the association between SP1 and GSK-3ß. Knockdown of GSK-3ß further verified our findings. Taken together, these results revealed that AKT/GSK-3ß-mediated stabilization of SP1 is required for TGF-ß induced up-regulation of NKG2DLs. Our study provided valuable evidence for exploring the tumour immune modulation function of TGF-ß.

Histone deacetylase inhibitors deplete myeloid-derived suppressor cells induced by 4T1 mammary tumors in vivo and in vitro.

Myeloid-derived suppressor cells (MDSC) have been identified as a population of immature myeloid cells that suppress anti-tumor immunity. MDSC are increased in tumor-bearing hosts; thus, depletion of MDSC may enhance anti-tumor immunity. Histone deacetylase inhibitors (HDACi) are chemical agents that are primarily used against hematologic malignancies. The ability of these agents to modulate anticancer immunity has recently been extensively studied. However, the effect of HDACi on MDSC has remained largely unexplored. In the present study, we provide the first demonstration that HDACi treatment decreases MDSC accumulation in the spleen, blood and tumor bed but increases the proportion of T cells (particularly the frequency of IFN-γ- or perforin-producing CD8+ T cells) in BALB/C mice with 4T1 mammary tumors. In addition, HDACi exposure of bone marrow (BM) cells significantly eliminated the MDSC population induced by GM-CSF or the tumor burden in vitro, which was further demonstrated as functionally important to relieve the inhibitory effect of MDSC-enriched BM cells on T cell proliferation. Mechanistically, HDACi increased the apoptosis of Gr-1+ cells (almost MDSC) compared with that of Gr-1- cells, which was abrogated by the ROS scavenger N-acetylcysteine, suggesting that the HDACi-induced increase in MDSC apoptosis due to increased intracellular ROS might partially account for the observed depletion of MDSC. These findings suggest that the elimination of MDSC using an HDACi may contribute to the overall anti-tumor properties of these agents, highlighting a novel property of HDACi as potent MDSC-targeting agents, which may be used to enhance the efficacy of immunotherapeutic regimens.

Calotropin from Asclepias curasavica induces cell cycle arrest and apoptosis in cisplatin-resistant lung cancer cells.

Calotropin (M11), an active compound isolated from Asclepias curasavica L., was found to exert strong inhibitory and pro-apoptotic activity specifically against cisplatin-induced resistant non-small cell lung cancer (NSCLC) cells (A549/CDDP). Molecular mechanism study revealed that M11 induced cell cycle arrest at the G2/M phase through down-regulating cyclins, CDK1, CDK2 and up-regulating p53 and p21. Furthermore, M11 accelerated apoptosis through the mitochondrial apoptotic pathway which was accompanied by increase Bax/Bcl-2 ratio, decrease in mitochondrial membrane potential, increase in reactive oxygen species production, activations of caspases 3 and 9 as well as cleavage of poly ADP-ribose polymerase (PARP). The activation and phosphorylation of JNK was also found to be involved in M11-induced apoptosis, and SP610025 (specific JNK inhibitor) partially prevented apoptosis induced by M11. In contrast, all of the effects that M11 induce cell cycle arrest and apoptosis in A549/CDDP cells were not significant in A549 cells. Drugs with higher sensitivity against resistant tumor cells than the parent cells are rather rare. Results of this study supported the potential application of M11 on the non-small lung cancer (NSCLC) with cisplatin resistance.

Nodal signaling modulates the expression of Oct-4 via nuclear translocation of ß-catenin in lung and prostate cancer cells.

Nodal is a member of transforming growth factor beta (TGF-ß) superfamily. Nodal promotes the self-renewal of human cancer stem cells (CSCs) and triggers carcinogenesis of human cancers via an autocrine manner through Smad2/3 pathway. In our study, generation of Nodal-overexpressed cancer cells was constructed, and the effect of Nodal on the stem cell marker Oct-4 was evaluated by overexpression or blocked Nodal/ALKs signaling pathway in non-small cell lung cancer cells A549 and prostate cancer cells PC3. Functionally, Nodal also increased the proliferation via the ß-catenin nuclear translocation. This increase was attributed to GSK-3ß dephosphorylating, and activin receptor-like kinase 4/7 (ALK4/7) played a major role in human cancer cells. Our study provides a positive understanding of Nodal function in cancer cells and suggests a potential novel target for clinical therapeutic research.

Changes in the proteomic profile during the differential polarization status of the human monocyte-derived macrophage THP-1 cell line.

Macrophages are heterogeneous and plastic populations that are an essential component of inflammation and host defense. To understand how macrophages respond to cytokine signals, we used 2DE to identify protein profiles in macrophages stimulated with interleukin 4 (M2) and those stimulated with lipopolysaccharide and interferon γ (M1). In total, 32 differentially expressed proteins in THP-1 cells were identified by MALDI-TOF MS/MS analysis. The different proteins were mainly involved in cellular structure, protein metabolism, stress response, oxidative response, and nitric oxide production during macrophage polarization. In particular, proteins playing important roles in production of nitric oxide (NO) were downregulated in M2 macrophages. Many antioxidant and heat shock proteins, which are related to oxidative response, were upregulated in M2 macrophages. More importantly, a remarkable decrease in intracellular ROS and NO production were detected in M2 macrophages. Our results provide a proteomic profile of differentially polarized macrophages and validate the function of the identified proteins, which may indicate possible mechanism of macrophage polarization process.

AKT/GSK-3ß regulates stability and transcription of snail which is crucial for bFGF-induced epithelial-mesenchymal transition of prostate cancer cells.

BACKGROUND: Epithelial-mesenchymal transition (EMT) plays a pivotal role in the development of metastatic cancers. Basic fibroblast growth factor (bFGF) is significantly elevated in metastatic prostate cancers, which has been mentioned mainly to induce EMT in normal cells. However, there is no description about bFGF induced EMT and its underlying mechanism in prostate cancer cells. METHODS: Western blotting, immunofluorescence and qRT-PCR assays were used to study protein or mRNA expression profiles of the EMT. Wound healing scratch, migration and invasion assays were used to test the motility of cells undergoing EMT. More methods were used to explore the underlying mechanisms. RESULTS: We demonstrated that bFGF promoted EMT and motility of human prostate cancer PC-3 cells. Both protein and mRNA expression of Snail were rapidly increased after bFGF treatment. Ectopic expression of Snail triggered EMT and enhanced cell motility in PC-3 cells, and knockdown of Snail almost abolished bFGF induced EMT, suggesting the critical role of Snail. Mechanistic study demonstrated that bFGF promoted the stability, nuclear localization and transcription of Snail by inhibiting the activity of glycogen synthase kinase 3 beta (GSK-3ß) through phosphatidylinositide 3 kinases (PI3K)/protein kinase B (AKT) signaling pathway. CONCLUSIONS: It is concluded that bFGF can promote EMT and motility of PC-3 cells, and AKT/GSK-3ß signaling pathway controls the stability, localization and transcription of Snail which is crucial for this bFGF induced EMT. GENERAL SIGNIFICANCE: To our knowledge, this is the first study to demonstrate that bFGF can induce EMT via AKT/GSK-3ß/Snail signaling pathway in prostate cancer cells.

Nodal promotes the generation of M2-like macrophages and downregulates the expression of IL-12.

Nodal, a member of the TGF-ß superfamily, is an embryonic morphogen that is upregulated in different types of tumors. Nodal increases the tumorigenesis by inducing angiogenesis and promoting metastasis. Importantly, Nodal inhibition suppresses the growth and invasion of tumor. Since tumor-associated macrophages (TAMs) are the major infiltrating leukocytes in most cancers, we investigated whether Nodal is involved in the differentiation of TAMs. Our results revealed that Nodal inhibition in tumor microenvironment upregulated the production of IL-12 in macrophages and reversed TAMs to classically activated macrophage phenotype. In contrast, treatment with recombinant Nodal (rNodal) decreased the expression of IL-12 in murine macrophages. Furthermore, rNodal promoted macrophage polarization to an alternatively activated macrophage-like/TAM phenotype and modulated its function. These results suggest that Nodal may play an important role in macrophage polarization and downregulation of IL-12. The rescued antitumor function of TAMs via the inhibition of Nodal expression could be a new therapeutic strategy for cancer treatment.

Trichostatin A, a histone deacetylase inhibitor, reverses epithelial-mesenchymal transition in colorectal cancer SW480 and prostate cancer PC3 cells.

Trichostatin A (TSA) is a kind of classical histone deacetylase (HDAC) inhibitor. In this study, we reported the reversal effects of TSA on EMT and investigated the possible involved molecular mechanisms in SW480 and PC3 cells. Firstly, we observed that TSA induced the reversal process of epithelial-mesenchymal transition (EMT) in SW480 and PC3 cells, resulting in attenuated cell invasion and migration abilities. TSA-induced EMT reversal was characterized by up-regulation of E-cadherin and down-regulation of Vimentin. Then, treatment with TSA also decreased the expression of transcription factor Slug. Furthermore, over-expression of Slug significantly caused down-regulation of E-cadherin and up-regulation of Vimentin. Meanwhile, TSA treatment in Slug-expressing cells could prevent these changes. These findings suggested that Slug played a crucial role in TSA-induced EMT reversal. Additionally, the study showed that TSA could induce the increase of HDAC1 and HDAC2 on the Slug gene promoter, which might be responsible for the suppression of Slug. Overall, TSA could reverse EMT in SW480 and PC3 cells and TSA-mediated down-regulation of Slug was involved in the reversal process.

Population Pharmacokinetics in China: The Dynamics of Intravenous Voriconazole in Critically Ill Patients with Pulmonary Disease.

Pharmacokinetic research in China on the use of voriconazole in critically ill adult patients with different pulmonary diseases remains to be explored. This study evaluated the population pharmacokinetics of the use of voriconazole (VRC) in critically ill patients to determine covariate effects on VRC pharmacokinetics by NONMEM, which could further optimize VRC dosing in this population. A one-compartment model with first-order absorption and elimination best fit the data, giving 4.28 L/h clearance and 93.4 L volume of distribution of VRC. The model variability, described as an approximate percentage coefficient of interindividual variability in clearance and volume of distribution, was 72.94% and 26.50%, respectively. A significant association between Cmin and drug response or grade 2 hepatotoxicity was observed (p=0.002, <0.001, respectively, 1.5-4.0 µg/mL) via logistic multivariate regression. Monte Carlo simulations at 100, 150, 200, and 250 mg dosage predicted effectiveness at 45.99%, 99.76%, 98.76%, and 67.75% within the 1.5-4.0 µg/mL range, suggesting that a 150 or 200 mg intravenous dose twice daily is best suited to achieve the target steady state trough concentration range in critically ill patients with pulmonary disease.

Histone deacetylase inhibitor induction of epithelial-mesenchymal transitions via up-regulation of Snail facilitates cancer progression.

Histone deacetylase inhibitors (HDACIs) are now emerging as a new class of anticancer drugs. Some of them have been used in clinical treatment for tumors, most impressively in the hematological tumors. But their single-agent activities in epithelial-derived tumors are limited. The mechanisms of these actions of HDACIs are not yet well understood. In this study, it was found for the first time that HDACIs were able to induce epithelial-mesenchymal transitions (EMT) which is believed to trigger tumor cell invasion and metastasis. We show that HDACIs induce fibroblast-like morphology, up-regulate Snail and Vimentin and down-regulate E-cadherin in epithelial cell-derived tumor cell lines. It demonstrates that HDACI treatment enhances further Snail acetylation and reduces its ubiquitylation, and induces Snail transcription as well as Snail nuclear translocation in CNE2 cells. Snail knockdown by siRNAs prevents the change in cell morphology and Vimentin up-regulation in response to HDACIs. The results suggested that Snail plays an important role in the HDACI-induced EMT. It is very crucial for a better understanding of clinical therapeutical failure of HDACIs in the patients with epithelial cell-derived cancers. Therefore, our results indicate that more attention should be paid to the cancer treatment using HDACIs due to the fact that it will enhance the spread risks of cancer cells to facilitate cancer progression and it is very important to select appropriate drugs for different tumors.

The role of indoleamine 2,3-dioxygenase (IDO) in immune tolerance: focus on macrophage polarization of THP-1 cells.

Macrophages can be divided into two groups as M1 and M2 phenotype. Our results and other groups revealed that IFN-γ can up-regulate the IDO expression and differentiate THP-1 cells to M1 phenotype. Therefore we hypothesized that IDO may play potential roles in macrophage differentiation. Interesting, our results indicated that the ectopic IDO increases the expression of M2 markers such as IL-10 and CXCR4 while decreases the M1 markers such as CCR7 and IL-12p35. In contrast, the knockdown of IDO expression in THP-1 cells resulted in increased M1 markers and lower M2 markers. Our results suggested that the expression intensity of IDO modulates macrophages differentiation. These finding support the counter-regulatory role for IDO with regarding to the polarization of macrophages to restrain excessive or inappropriate immune activation in inflammatory or tumor microenvironment. It throws new light on the mechanisms about the immunosuppressive effect of IDO in tumor or inflammatory diseases.

Snail regulated by PKC/GSK-3ß pathway is crucial for EGF-induced epithelial-mesenchymal transition (EMT) of cancer cells.

Cancer metastasis is considered a major challenge in cancer therapy. Recently, epidermal growth factor (EGF)/epidermal growth factor receptor (EGFR) signaling has been shown to induce epithelial-mesenchymal transition (EMT) and thereby to promote cancer metastasis. However, the underlying mechanism has not been fully elucidated. We demonstrate that EGF can induce EMT in human prostate and lung cancer cells and thus promote invasion and migration. EGF-induced EMT has been characterized by the cells acquiring mesenchymal spindle-like morphology and increasing their expression of N-cadherin and fibronectin, with a concomitant decrease of E-cadherin. Both protein and mRNA expression of transcription factor Snail rapidly increases after EGF treatment. The knockdown of Snail significantly attenuates EGF-induced EMT, suggesting that Snail is crucial for this process. To determine the way that Snail is accumulated, we demonstrate (1) that EGF promotes the stability of Snail via inhibiting the activity of glycogen synthase kinase 3 beta (GSK-3ß), (2) that protein kinase C (PKC) rather than the phosphatidylinositide 3-kinase (PI3K)/protein kinase B (AKT) signaling pathway is responsible for GSK-3ß inhibition and (3) that GSK-3ß inhibition promotes the transcription of Snail. Taken together, these results reveal that the PKC/GSK-3ß signaling pathway controls both the stability and transcription of Snail, which is crucial for EMT induced by EGF in PC-3 and A549 cells. Our study suggests a novel signaling pathway for Snail regulation and provides a better understanding of growth-factor-induced tumor EMT and metastasis.

Time to Local Recurrence as a Predictor of Survival in Adult Head and Neck Soft Tissue Sarcoma.

OBJECTIVES: We sought to evaluate the impact of the time interval from surgical resection to local recurrence (TTLR) on clinical outcomes in head and neck soft tissue sarcoma (HNSTS). METHODS: A total of 401 patients who underwent R0 resection for primary HNSTS were included in this study. Patients with local recurrence as the first event after their initial resection were divided into early local recurrence (ELR) or late local recurrence (LLR) groups according to TTLR. Multiple survival analyses were performed to identify the independent prognostic predictors of overall survival (OS) and survival after local recurrence (SAR). RESULTS: Two hundred and nine of the 401 patients (52.1%) developed local recurrence during a median follow-up period of 134.6 months. Patients in the ELR group had a shorter median OS time (35.0 vs. 120.6, p < 0.001) and lower 5-year OS rate (47.7% vs. 80.9%, p < 0.001) than those in the LLR group. Moreover, the ELR group exhibited worse SAR (p = 0.001) than the LLR group, and multivariate analyses demonstrated TTLR as an independent prognostic factor for SAR (p = 0.048) and OS (p = 0.004). Additionally, re-resection significantly prolonged SAR than other salvage interventions or no treatment (p < 0.001). CONCLUSION: In patients with HNSTS, ELR after R0 resection presents adverse effects on OS and SAR than those with LLR, and TTLR could serve as a promising predictor for survival. Salvage therapies, especially the re-resection could improve SAR and should be recommended when there are surgical indications after recurrence. LEVEL OF EVIDENCE: 3 Laryngoscope, 133:2174-2182, 2023.

Targeting eradication of malignant cells derived from human bone marrow mesenchymal stromal cells.

Human bone marrow mesenchymal stromal cells (hBMSC) have been shown to participate in malignant transformation. However, hampered by the low frequency of malignant transformation of hBMSC, we do not yet know how to prevent malignant transformation of implanted hBMSC. In this study, in order to establish a model for the eradication of hBMSC-derived malignant cells, a gene fusion consisting of a human telomerase (hTERT) promoter modified with both c-Myc and myeloid zinc finger protein2 (MZF-2) binding elements and followed by the E. coli cytosine deaminase (CD) and luciferase genes was stably transferred into hBMSC via lentiviral transduction; n-phosphonacelyl-L-aspartic acid (PALA) selection was used to generate malignant cell colonies derived from transduced hBMSC after treatment with the carcinogenic reagent BPDE. Cells that were amplified after PALA selection were used for transplantation and 5-FC pro-drug cytotoxicity tests. The results showed that PALA-resistant malignant cells could be generated from hBMSC co-induced with lentiviral transduction and treatment with Benzo(a)pyrene Diol Epoxide (BPDE); the modification of c-Myc and MZF-2 binding elements could remarkably enhance the transcriptional activities of the hTERT promoter in malignant cells, whereas transcriptional activity was depressed in normal hBMSC; malignant cells stably expressing CD under the control of the modified hTERT promoter could be eliminated by 5-FC administration. This study has provided a method for targeted eradication of malignant cells derived from hBMSC.

QSAR Studies on andrographolide derivatives as α-glucosidase inhibitors.

Andrographolide derivatives were shown to inhibit alpha-glucosidase. To investigate the relationship between activities and structures of andrographolide derivatives, a training set was chosen from 25 andrographolide derivatives by the principal component analysis (PCA) method, and a quantitative structure-activity relationship (QSAR) was established by 2D and 3D QSAR methods. The cross-validation r(2) (0.731) and standard error (0.225) illustrated that the 2D-QSAR model was able to identify the important molecular fragments and the cross-validation r(2) (0.794) and standard error (0.127) demonstrated that the 3D-QSAR model was capable of exploring the spatial distribution of important fragments. The obtained results suggested that proposed combination of 2D and 3D QSAR models could be useful in predicting the alpha-glucosidase inhibiting activity of andrographolide derivatives.

Expression of indoleamine 2,3-dioxygenase in nasopharyngeal carcinoma impairs the cytolytic function of peripheral blood lymphocytes.

BACKGROUND: Tumor-specific cytotoxic T cells and infiltrating lymphocytes are frequently found in tumor tissues in patients with nasopharyngeal carcinoma (NPC). Most patients with NPC, however, especially those with advanced stages, have a poor clinical prognosis despite conventional immunotherapy. The aim of this work was to examine the effect of indoleamine 2,3-dioxygenase (IDO), an immunosuppressive enzyme, on the lymphocyte function in NPC. METHODS: The NPC cell line CNE2 was treated by interferon-gamma (IFNgamma) and the levels of IDO expression was analyzed by Western blotting and reverse phase high-performance liquid chromatography (HPLC). Lymphocytes from health human exposed to the milieu created by IDO-positive CNE2 cells and the lymphocyte cytotoxicity to target tumor cells was analyzed by standard lactate dehydrogenase (LDH) release assay. Additionally, expression of IDO was determined by Immunohistochemical assay in the tumor tissues form clinically evaluated NPC. RESULTS: IDO expression was acutely induced in the NPC cell line CNE2 by low dose interferon-gamma (IFNgamma) or by co-incubation with activated lymphocytes. Exposure to the milieu created by IDO-positive CNE2 cells did not promote lymphocyte death, but lymphocyte cytotoxicity against target tumor cells was impaired. The suppression of lymphocyte cytotoxic function was fully restored when the conditioned medium was replaced by fresh medium for 24 h. In additionally, the IDO-positive cells were found scattered in the tumor tissues from patients with NPC. CONCLUSION: Altogether, these findings suggest that IDO-mediated immunosuppression may be involved in the tumor immune evasion, and that blocking IDO activity in tumor cells may help to re-establish an effective anti-tumor T cell response in NPC.

Nodal Facilitates Differentiation of Fibroblasts to Cancer-Associated Fibroblasts that Support Tumor Growth in Melanoma and Colorectal Cancer.

Fibroblasts become cancer-associated fibroblasts (CAFs) in the tumor microenvironment after activation by transforming growth factor-ß (TGF-ß) and are critically involved in cancer progression. However, it is unknown whether the TGF superfamily member Nodal, which is expressed in various tumors but not expressed in normal adult tissue, influences the fibroblast to CAF conversion. Here, we report that Nodal has a positive correlation with α-smooth muscle actin (α-SMA) in clinical melanoma and colorectal cancer (CRC) tissues. We show the Nodal converts normal fibroblasts to CAFs, together with Snail and TGF-ß signaling pathway activation in fibroblasts. Activated CAFs promote cancer growth in vitro and tumor-bearing mouse models in vivo. These results demonstrate that intercellular crosstalk between cancer cells and fibroblasts is mediated by Nodal, which controls tumor growth, providing potential targets for the prevention and treatment of tumors.

Interfering with cellular signaling pathways enhances sensitization to combined sodium butyrate and GCV treatment in EBV-positive tumor cells.

The combination of sodium butyrate (NaB) and ganciclovir (GCV) was considered to be a noteworthy therapeutic strategy in Epstein-Barr virus (EBV)-associated cancers. However, clinical studies have indicated that an extremely high dose of NaB is required to obtain the expected curative efficacy. This obviously limits the practical clinical application of the two drugs combined. In this study, we investigated the possibility of sensitizing tumor cells to NaB and GCV mediated cytotoxicity by modulating intracellular signal pathways. The results showed that the disruption of Ras/Raf activity by expressing dominant negative forms of both Ras and Raf-1 did not alter the potency of the NaB and GCV combination in the EBV-positive cell line, B95-8. However, blocking Akt activity by expressing its dominant negative form remarkably promoted NaB and GCV-mediated cytotoxicity via a thymidine kinase (TK)-independent mechanism. Interestingly, it was found that the constitutive activation of mitogen-activated protein kinase kinase kinase 1 (MEKK1) dramatically enhanced the sensitization of the cells to the combination of NaB and GCV, accompanied with an increase in TK expression in B95-8 cells. These results suggest that interfering with either the Akt or MEKK1 signaling pathway may be a useful therapeutic strategy to increase the sensitivity of EBV-positive tumor cells to the combination of NaB and GCV.