Chmp 1A is a mediator of the anti-proliferative effects of all-trans retinoic acid in human pancreatic cancer cells

ProstaMine: a bioinformatics tool for identifying subtype-specific co-alterations associated with aggressiveness in prostate cancer

Background

Prostate cancer is a leading cause of cancer-related deaths among men, marked by heterogeneous clinical and molecular characteristics. The complexity of the molecular landscape necessitates tools for identifying multi-gene co-alteration patterns that are associated with aggressive disease. The identification of such gene sets will allow for deeper characterization of the processes underlying prostate cancer progression and potentially lead to novel strategies for treatment.

Methods

We developed ProstaMine to systematically identify co-alterations associated with aggressiveness in prostate cancer molecular subtypes defined by high-fidelity alterations in primary prostate cancer. ProstaMine integrates genomic, transcriptomic, and clinical data from five primary and one metastatic prostate cancer cohorts to prioritize co-alterations enriched in metastatic disease and associated with disease progression.

Results

Integrated analysis of primary tumors defined a set of 17 prostate cancer alterations associated with aggressive characteristics. We applied ProstaMine to NKX3-1-loss and RB1-loss tumors and identified subtype-specific co-alterations associated with metastasis and biochemical relapse in these molecular subtypes. In NKX3-1-loss prostate cancer, ProstaMine identified novel subtype-specific co-alterations known to regulate prostate cancer signaling pathways including MAPK, NF-kB, p53, PI3K, and Sonic hedgehog. In RB1-loss prostate cancer, ProstaMine identified novel subtype-specific co-alterations involved in p53, STAT6, and MHC class I antigen presentation. Co-alterations impacting autophagy were noted in both molecular subtypes.

Conclusion

ProstaMine is a method to systematically identify novel subtype-specific co-alterations associated with aggressive characteristics in prostate cancer. The results from ProstaMine provide insights into potential subtype-specific mechanisms of prostate cancer progression which can be formed into testable experimental hypotheses. ProstaMine is publicly available at: https://bioinformatics.cuanschutz.edu/prostamine.

Proposing new early detection indicators for pancreatic cancer: Combining machine learning and neural networks for serum miRNA-based diagnostic model

Background

Pancreatic cancer (PC) is a lethal malignancy that ranks seventh in terms of global cancer-related mortality. Despite advancements in treatment, the five-year survival rate remains low, emphasizing the urgent need for reliable early detection methods. MicroRNAs (miRNAs), a group of non-coding RNAs involved in critical gene regulatory mechanisms, have garnered significant attention as potential diagnostic and prognostic biomarkers for pancreatic cancer (PC). Their suitability stems from their accessibility and stability in blood, making them particularly appealing for clinical applications.

Methods

In this study, we analyzed serum miRNA expression profiles from three independent PC datasets obtained from the Gene Expression Omnibus (GEO) database. To identify serum miRNAs associated with PC incidence, we employed three machine learning algorithms: Support Vector Machine-Recursive Feature Elimination (SVM-RFE), Least Absolute Shrinkage and Selection Operator (LASSO), and Random Forest. We developed an artificial neural network model to assess the accuracy of the identified PC-related serum miRNAs (PCRSMs) and create a nomogram. These findings were further validated through qPCR experiments. Additionally, patient samples with PC were classified using the consensus clustering method.

Results

Our analysis revealed three PCRSMs, namely hsa-miR-4648, hsa-miR-125b-1-3p, and hsa-miR-3201, using the three machine learning algorithms. The artificial neural network model demonstrated high accuracy in distinguishing between normal and pancreatic cancer samples, with verification and training groups exhibiting AUC values of 0.935 and 0.926, respectively. We also utilized the consensus clustering method to classify PC samples into two optimal subtypes. Furthermore, our investigation into the expression of PCRSMs unveiled a significant negative correlation between the expression of hsa-miR-125b-1-3p and age.

Conclusion

Our study introduces a novel artificial neural network model for early diagnosis of pancreatic cancer, carrying significant clinical implications. Furthermore, our findings provide valuable insights into the pathogenesis of pancreatic cancer and offer potential avenues for drug screening, personalized treatment, and immunotherapy against this lethal disease.

Isolation and proteomic profiling of urinary exosomes from patients with colorectal cancer

Exosomes in the body fluid are effective cell-derived membranous structures transferring various molecules to mediate intercellular communication. The expression of protein in the urinary exosomes from the colorectal cancer (CRC) patients could reflect the characteristics of tumorigenesis. The urinary exosomes with globular membrane structure, the size of 30 ~ 100 nm and positive expression of CD9, CD63 and CD81 were successfully isolated from 9 CRC patients and 3 heathy adults using the density gradient ultracentrifugation. Proteome profiles revealed by label-free liquid chromatography-tandem mass spectrometry (LC-MS/MS) indicated that several proteins were differentially expressed among different stages of CRC. Compared with normal controls, 67 proteins in CRC urinary exosomes were upregulated and 74 proteins were downregulated. The bioinformatics analysis revealed the decreased proteins were related to ESCRT III complex disassembly. The CHMP family was further determined to be the hub of interaction network of proteins enriched in ESCRT signaling. The significant decrease of CHMP4A, CHMP4B, CHMP2A, CHMP2B and CHMP1B were respectively found in the total CRC group and distant metastasis group compared with NC group. Moreover, the CEACAM family also showed significant aberrant changes in the urinary exosomes of CRC patients. The CEACAM7 and CEACAM1 were increased in the CRC patients compared with healthy individuals (P < 0.05). Significant changes of proteomic profile could be found in the urinary exosomes in the CRC patients. The differential expressed urinary exosomes derived proteins showed potential usage in diagnosis and prognosis of CRC.

CHMP1A suppresses the growth of renal cell carcinoma cells via regulation of the PI3K/mTOR/p53 signaling pathway

BACKGROUND

CHMP1A, a member of the ESCRT-III complex family, has been indicated as a brand-new inhibitor gene of tumors. Our previous research has revealed that CHMP1A plays a vital role in the development and progression of renal cell carcinoma (RCC).

OBJECTIVE

To investigate the potential target pathway of the regulation of the tumor cell growth by CHMP1A.

METHODS

The effect of CHMP1A on mTOR pathway was elucidated by western blotting. The effect of CHMP1A on the expression of p53 was evaluated, and A498 cell growth was assessed by colony formation and MTT assays. The expression of p53 was knocked down by shRNA-p53, and the effect of CHMP1A on mTOR after knockdown of p53 was evaluated. The effect of CHMP1A on apoptosis and its relationship with MDM2 pathway were detected by western blotting and FCM. Finally, the relationship between the regulation of p53 by CHMP1A and the PI3K/mTOR pathway was detected.

RESULTS

This study showed that the mTOR pathway was suppressed significantly in CHMP1A-overexpressing A498 and 786-0 cells; moreover, the enhanced expression of p53 and the reduced proliferation were shown in CHMP1A-overexpressing A498 cells. Furthermore, CHMP1A was able to regulate the PI3K/PTEN/mTOR and MDM2/p53 pathways in order to suppress RCC. In addition, CHMP1A regulated Bax and Bcl-2 via MDM2/p53 to induce the apoptosis of tumor cells and upregulated the expression of p53 via the PI3K/mTOR pathway.

CONCLUSIONS

The results convey that CHMP1A-related suppression of RCC is closely related to the PI3K/mTOR/p53 pathway.

Multidimensional Analysis of CHMP Family Members in Hepatocellular Carcinoma

Background

EGFR frequently accumulates and mutates simultaneously in various cancers. Ubiquitinated EGFR proteins can be degraded by the endosomal sorting complex required for transport. Among them, ESCRTIII is mainly composed of CHMP family members.

Methods

A total of 424 samples from the TCGA-LIHC data set were used to explore the relationship between CHMPs and liver hepatocellular carcinoma (LIHC). Oncomine, the Human Protein Altas, cBioPortal, TISIDB, TIMER, Metascape, and R software were used to facilitate analysis of the role played by CHMPs in the pathogenesis of LIHC. The role of CHMPs in the development of LIHC was analyzed in terms of differential expression, survival, mutation, immunoinfiltration, functional enrichment, and drug sensitivity.

Results

Differential expression analysis showed that CHMPs were significantly more expressed in LIHC tumor tissue, and the high expression of some CHMPs was closely correlated with clinicopathological stage. The prognosis was worse in the group with high expression of CHMPs. Among them, CHMP4C was considered to play a major role. Gene-mutation analysis and DNA promoter–methylation analysis further revealed possible mechanisms for the aberrant amplification of CHMPs. Immunoinfiltration analysis indicated that CHMPs were closely associated with multiple immune cells and exhibited resistance to various drugs when highly expressed.

Conclusion

CHMPs were found to be significantly elevated in LIHC and strongly associated with immune-cell infiltration, poor prognosis, multiple star pathways, and drug resistance.

The potential roles of p53 signaling reactivation in pancreatic cancer therapy

Globally, pancreatic cancer (PC) is a common and highly malignant gastrointestinal tumor that is characterized by an insidious onset and ready metastasis and recurrence. Over recent decades, the incidence of PC has been increasing on an annual basis; however, the pathogenesis of this condition remains enigmatic. PC is not sensitive to radio- or chemotherapy, and except for early surgical resection, there is no curative treatment regime; consequently, the prognosis for patients with PC is extremely poor. Transcription factor p53 is known to play key roles in many important biological processes in vertebrates, including normal cell growth, differentiation, cell cycle progression, senescence, apoptosis, metabolism, and DNA damage repair. However, there is a significant paucity of basic and clinical studies to describe how p53 gene mutations or protein dysfunction facilitate the occurrence, progression, invasion, and resistance to therapy, of malignancies, including PC. Herein, we describe the involvement of p53 signaling reactivation in PC treatment as well as its underlying molecular mechanisms, thereby providing useful insights for targeting p53-related signal pathways in PC therapy.

Targeting PIN1 exerts potent antitumor activity in pancreatic ductal carcinoma via inhibiting tumor metastasis

The human prolyl isomerase PIN1, best known for its association with carcinogenesis, has recently been indicated in the disease of pancreatic ductal adenocarcinoma (PDAC). However, the functions of PIN1 and the feasibility of targeting PIN1 in PDAC remain elusive. For this purpose, we examined the expression of PIN1 in cancer, related paracarcinoma and metastatic cancer tissues by immunohistochemistry and analyzed the associations with the pathogenesis of PDAC in 173 patients. The functional roles of PIN1 in PDAC were explored in vitro and in vivo using both genetic and chemical PIN1 inhibition. We showed that PIN1 was upregulated in pancreatic cancer and metastatic tissues. High PIN1 expression is significantly association with poor clinicopathological features and shorter overall survival and disease‐free survival. Further stratified analysis showed that PIN1 phenotypes refined prognostication in PDAC. Inhibition of PIN1 expression with RNA interference or with all trans retinoic acid decreased not only the growth but also the migration and invasion of PDAC cells through regulating the key molecules of multiple cancer‐driving pathways, simultaneously resulting in cell cycle arrest and mesenchymal‐epithelial transition in vitro. Furthermore, genetic and chemical PIN1 ablation showed dramatic inhibition of the tumorigenesis and metastatic spread and then reduced the tumor burden in vivo. We provided further evidence for the use of PIN1 as a promising therapeutic target in PDAC. Genetic and chemical PIN1 ablation exerted potent antitumor effects through blocking multiple cancer‐driving pathways in PDAC. More potent and specific PIN1 targeted inhibitors could be exploited to treat this aggressive cancer.

The Pleiotropic Role of Retinoic Acid/Retinoic Acid Receptors Signaling: From Vitamin A Metabolism to Gene Rearrangements in Acute Promyelocytic Leukemia

The family of retinoic acid receptors (RARs: RARα, -β, and -γ) has remarkable pleiotropy characteristics, since the retinoic acid/RARs pathway is involved in numerous biological processes not only during embryonic development, but also in the postnatal phase and during adulthood. In this review, we trace the roles of RA/RARs signaling in the immune system (where this pathway has both an immunosuppressive role or is involved in the inflammatory response), in hematopoiesis (enhancing hematopoietic stem cell self-renewal, progenitor cells differentiation or maintaining the bone marrow microenvironment homeostasis), and in bone remodeling (where this pathway seems to have controversial effects on bone formation or osteoclast activation). Moreover, in this review is shown the involvement of RAR genes in multiple chromosomal rearrangements generating different fusion genes in hematological neoplasms, with a particular focus on acute promyelocytic leukemia and its variant subtypes. The effect of different RARs fusion proteins on leukemic transformation, on patients’ outcome, and on therapy response is also discussed.

Antitumor effects of all-trans retinoic acid and its synergism with gemcitabine are associated with downregulation of p21-activated kinases in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDA) is one of the most lethal malignancies worldwide. All-trans retinoic acid (ATRA) has been used as an antistromal agent in PDA, and its antitumor effect has also been reported in various kinds of cancer, including PDA. Inhibition of p21-activated kinases (PAKs) is associated with decreased tumor growth and increased gemcitabine sensitivity. The aim of this study was to evaluate the inhibitory effects of ATRA alone and in combination with gemcitabine on cell growth and migration of wild-type and gemcitabine-resistant PDA cells and the potential mechanism(s) involved. Human (MiaPaCa-2) and murine (TB33117) PDA cell lines were incubated in increasing concentrations of gemcitabine to establish resistant clones. Cell growth, clonogenicity, and migration/invasion were determined using a sulforhodamine B assay, a colony formation assay, and a Boyden chamber assay, respectively. Protein expression was measured by Western blotting. ATRA reduced cell proliferation, colony formation, and migration/invasion in both wild-type and gemcitabine-resistant cell lines. PAK1 expression was significantly increased in resistant cells. Cells treated with ATRA showed decreased expression of PAK1, PAK2, PAK4, and α-smooth muscle actin. The combination of ATRA and gemcitabine synergistically reduced cell growth in both wild-type and gemcitabine-resistant cell lines. Depletion of PAK1 enhanced ATRA sensitivity in MiaPaCa-2 cells. In conclusion, the antitumor effects of ATRA and its synergism with gemcitabine are associated with downregulation of PAKs. NEW & NOTEWORTHY The inhibitory effect of all-trans retinoic acid (ATRA) on cell proliferation, colony formation, and migration/invasion was associated with downregulation of p21-activated kinases (PAKs), and depletion of PAK1 enhanced ATRA sensitivity in MiaPaCa-2 cells. The combination of ATRA and gemcitabine synergistically reduced cell growth in both wild-type and gemcitabine-resistant pancreatic ductal adenocarcinoma cells. As an important prognostic marker, α-smooth muscle actin also can be downregulated by ATRA in pancreatic ductal adenocarcinoma cells.

A prognostic mRNA expression signature of four 16q24.3 genes in radio(chemo)therapy-treated head and neck squamous cell carcinoma (HNSCC)

Previously, we have shown that copy number gain of the chromosomal band 16q24.3 is associated with impaired clinical outcome of radiotherapy‐treated head and neck squamous cell carcinoma (HNSCC) patients. We set out to identify a prognostic mRNA signature from genes located on 16q24.3 in radio(chemo)therapy‐treated HNSCC patients of the TCGA (The Cancer Genome Atlas, n = 99) cohort. We applied stepwise forward selection using expression data of 41 16q24.3 genes. The resulting optimal Cox‐proportional hazards regression model included the genes APRT, CENPBD1, CHMP1A, and GALNS. Afterward, the prognostic value of the classifier was confirmed in an independent cohort of HNSCC patients treated by adjuvant radio(chemo)therapy (LMU‐KKG cohort). The signature significantly differentiated high‐ and low‐risk patients with regard to overall survival (HR = 2.01, 95% CI 1.10–3.70; P = 0.02125), recurrence‐free survival (HR = 1.84, 95% CI 1.01–3.34; P = 0.04206), and locoregional recurrence‐free survival (HR = 1.87, 95% CI 1.03–3.40; P = 0.03641). The functional impact of the four signature genes was investigated after reconstruction of a gene association network from transcriptome data of the TCGA HNSCC cohort using a partial correlation approach. Subsequent pathway enrichment analysis of the network neighborhood (first and second) of the signature genes suggests involvement of HNSCC‐associated signaling pathways such as apoptosis, cell cycle, cell adhesion, EGFR, JAK‐STAT, and mTOR. Furthermore, a detailed analysis of the first neighborhood revealed a cluster of co‐expressed genes located on chromosome 16q, substantiating the impact of 16q24.3 alterations in poor clinical outcome of HNSCC. The reported gene expression signature represents a prognostic marker in HNSCC patients following postoperative radio(chemo)therapy.

Retinoic acid receptor α expression exerts an anti-apoptosis effect on PC12 cells following oxygen-glucose deprivation

It has been established that the primary form of neuron death following hypoxic ischemic brain damage is apoptosis. Imbalances in the expression of genes in the B-cell lymphoma 2 (Bcl-2) family located in the mitochondrion, and in the expression of their encoded proteins, are key events in the mitochondrial apoptotic pathway, which lead to damage of cellular structure and function. The present study aimed to explore the regulatory effect of retinoic acid receptor α (RAR-α) on the apoptosis of PC12 cells induced by oxygen-glucose deprivation (OGD) in the retinoic acid signaling pathway. Recombinant adenovirus RAR-α small interfering RNA (Ad-siRAR-α) was used to transduce PC12 cells, and the efficiency of RAR-α expression inhibition was detected by semi-quantitative reverse transcription polymerase chain reaction (RT-PCR). An empty adenovirus vector was transfected in PC12 cells, which were used as the control. Flow cytometry with Annexin V-propidium iodide (PI) and fluorescence probe JC-1 staining was used to detect the apoptosis rate and mitochondrial transmembrane potential (MMP), respectively, of PC12 cells after transduction with Ad-siRAR-α. Furthermore, the expression levels of key genes in the RAR-α and mitochondrial apoptotic pathway, Bcl-2 and Bcl-2-associated protein (Bax) were analyzed by RT-quantitative (q)PCR and western blot analysis. RAR-α mRNA expression was observed to be decreased in PC12 cells following OGD-induced injury, and this decrease can be reversed by 4 µmol/l ATRA treatment. After 36 h transfection with Ad-siRAR-α, RAR-α gene expression was significantly inhibited compared with the control (P<0.05). The results of Annexin V-PI, fluorescence probe JC-1 staining and flow cytometry demonstrated that the apoptosis rate significantly increased and MMP significantly decreased in OGD-induced PC12 cells following transduction with Ad-siRAR-α compared with the control (both P<0.05). RT-qPCR and western blot analysis indicated that Bax expression was significantly increased and Bcl-2 expression was significantly decreased in PC12 cells transduced with Ad-siRAR-α after OGD-induced injury at the mRNA and protein level (P<0.05). In conclusion, Ad-siRAR-α transduction could promote apoptosis in OGD-induced PC12 cells. This suggests that the expression of Bax and Bcl-2 in the mitochondrial apoptosis signaling pathway is, at least in part, mediated by RAR-α expression, thereby indicating that RAR-α expression exerts an anti-apoptotic effect on OGD-damaged PC12 cells.

Anacardic acid inhibits pancreatic cancer cell growth, and potentiates chemotherapeutic effect by Chmp1A - ATM - p53 signaling pathway

BACKGROUND

Pancreatic cancer is one of the leading causes of cancer related death and its incidence has risen steadily. Although anticancer drugs have been developed based on the new molecular findings, the drugs have produced unsatisfactory results due to toxicity and resistance. Thus, a complementary therapeutic intervention is urgently needed for pancreatic cancer patients.

METHODS

The aim of this study was to assess the potential therapeutic effect of Anacardic acid on pancreatic cancer in vitro and elucidate its underlying mechanisms. Human pancreatic cancer cells were treated with Anacardic acid and assessed for the cytotoxic effect using MTT and spheroid formation assays. Using the same methods, the synergy between Anacardic acid and 5-Fluorouracil or Gemcitabine was determined. To elucidate the underlying molecular mechanisms, Western blot analysis and immunocytochemistry were performed on cancer cells treated with Anacardic acid alone or in combination with 5-Fluorouracil or Gemcitabine. Chromatin Modifying Protein 1A (Chmp1A), Ataxia Telangiectasia Mutated (ATM), and p53 were the primary signaling molecules examined. In addition, Chmp1A was silenced with shRNA to examine the necessity of Chmp1A for the anticancer effect of Anacardic acid, 5-Fluorouracil, or Gemcitabine.

RESULTS

Anacardic acid induced an anticancer effect in pancreatic cancer cell lines in a dose dependent manner, and increased the cytotoxicity of 5-Fluorouracil or Gemcitabine in MTT cell viability assays. In spheroid formation assays, spheroids formed were smaller in size and in number upon Anacardic acid treatment compared to control. Mechanistically, Anacardic acid exerted its anticancer activity via the activation of Chmp1A, ATM, and p53. Interestingly, 5-Fluorouracil and Gemcitabine also induced an increase in Chmp1A protein level, suggesting that Chmp1A might mediate the cytotoxic action of chemotherapeutics. Silencing experiments indicate that Chmp1A is required for the action of Anacardic acid, but not for 5-Fluorouracil or Gemcitabine.

CONCLUSIONS

Our data suggests that Anacardic Acid might be a promising complementary supplement to slow the initiation or progression of pancreatic cancer.

ESCRT genes and regulation of developmental signaling

ESCRT (Endosomal Sorting Complex Required for Transport) proteins have been shown to control an increasing number of membrane-associated processes. Some of these, and prominently regulation of receptor trafficking, profoundly shape signal transduction. Evidence in fungi, plants and multiple animal models support the emerging concept that ESCRTs are main actors in coordination of signaling with the changes in cells and tissues occurring during development and homeostasis. Consistent with their pleiotropic function, ESCRTs are regulated in multiple ways to tailor signaling to developmental and homeostatic needs. ESCRT activity is crucial to correct execution of developmental programs, especially at key transitions, allowing eukaryotes to thrive and preventing appearance of congenital defects.

Cancer-associated fibroblasts in pancreatic adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is one of the most highly malignant tumors with a very poor prognosis. In addition to the cancer cells, the stroma of tumor can expand by 50% and influence cancer cell growth. Cancer-associated fibroblasts (CAFs) are important components of tumor stroma. Cancer cells, normal fibroblasts, normal epithelial cells as well as bone marrow-derived myofibroblasts contribute to the emergence of CAFs through various cytokines (e.g., TGF-β, SHH, PDGF) and epithelial-to-mesenchymal transition. CAFs affect cancer growth, survival, metastasis, angiogenesis and immunosurveillance through the secretion of various cytokines, such as CXCL12 and secreted protein acidic and rich in cystein. Also, CAFs correlate to the prognosis and chemoresistance of PDAC patients. As novel therapeutic targets, CAFs, and their relative factors, represent an important role in PDAC therapy.

All-trans retinoic acid suppresses apoptosis in PC12 cells injured by oxygen and glucose deprivation via the retinoic acid receptor α signaling pathway

Vitamin A (VA) has a number of important biological functions in human growth and development. Previous studies by our group demonstrated that the normal VA levels improved recovery of learning and memory function and decreased apoptosis in rats with hypoxic‑ischemic brain damage (HIBD). However, it has not been fully elucidated how VA regulates the apoptosis of neuronal cells. To investigate the anti‑apoptotic effect of VA, an in vitro oxygen glucose deprivation (OGD) model in PC12 cells was treated with four concentrations of all‑trans‑retinoic acid (ATRA), an active in vivo product of VA. Following in vitro OGD injury in PC12 cells, the percentage of apoptosis and the fluorescence intensity of the mitochondrial membrane potential (MMP) were increased in the cells, and the expression levels of B-cell lymphoma-associated X (Bax) were enhanced. ATRA treatment at 2‑4 µmol/l for 24 h decreased the percentage of apoptosis and the MMP of the PC12 cells injured by OGD. ATRA at 4 µmol/l also reduced the expression levels of Bax and enhanced the expression of B-cell lymphoma 2. Furthermore, RNA interference with retinoic acid receptor α (RARα) reversed the observed effect in PC12 cells following ATRA treatment at 4 µmol/l alone. In conclusion, the present study suggested that treatment with ATRA at 4 µmol/l suppressed apoptosis of PC12 cells following OGD injury, potentially through regulation of the RARα signaling pathway.

The Drosophila Chmp1 protein determines wing cell fate through regulation of epidermal growth factor receptor signaling

BACKGROUND

Receptor down-regulation by the multivesicular body (MVB) pathway is critical for many cellular signaling events. MVB generation is mediated by the highly conserved ESCRT (0, I, II, and III) protein complexes. Chmp1 is an ESCRT-III component and a putative tumor suppressor in humans. However, published data on Chmp1 activity are conflicting and its role during tissue development is not well defined.

RESULTS

We investigated the function of Drosophila Chmp1 and found that it is an essential gene. In the wing, loss of Chmp1 activity causes a cell fate change from intervein to vein, and interactions between Chmp1 and Drosophila Epidermal Growth Factor Receptor (DER) regulators suggest that Chmp1 negatively regulates DER signaling. Chmp1 knockdown also decreases Blistered expression, which is repressed by DER signaling. We find that Chmp1 protein localizes to the late endosome in Drosophila embryos, which is consistent with its effects on DER signaling resulting from its function in the ESCRT-III complex.

CONCLUSIONS

Drosophila Chmp1 negatively regulates DER signaling, likely through its role in MVB formation. Loss of Chmp1 activity in the Drosophila wing induces a cell fate change from intervein to vein that should provide a useful tool for future studies of ESCRT protein activity.

Pathway analysis for drug repositioning based on public database mining

Sixteen FDA-approved drugs were investigated to elucidate their mechanisms of action (MOAs) and clinical functions by pathway analysis based on retrieved drug targets interacting with or affected by the investigated drugs. Protein and gene targets and associated pathways were obtained by data-mining of public databases including the MMDB, PubChem BioAssay, GEO DataSets, and the BioSystems databases. Entrez E-Utilities were applied, and in-house Ruby scripts were developed for data retrieval and pathway analysis to identify and evaluate relevant pathways common to the retrieved drug targets. Pathways pertinent to clinical uses or MOAs were obtained for most drugs. Interestingly, some drugs identified pathways responsible for other diseases than their current therapeutic uses, and these pathways were verified retrospectively by in vitro tests, in vivo tests, or clinical trials. The pathway enrichment analysis based on drug target information from public databases could provide a novel approach for elucidating drug MOAs and repositioning, therefore benefiting the discovery of new therapeutic treatments for diseases.

Chmp1A acts as a tumor suppressor gene that inhibits proliferation of renal cell carcinoma

Renal cell carcinoma (RCC) is a highly malignant and often fatal disease of the kidney. Chmp1A is a member of the Endosomal Sorting Complex Required for Transport (ESCRT-III) family, and plays a role in the cytoplasm in sorting proteins to the multivesicular body (MVB). Chmp1A functions as a tumor suppressor gene and has been reported in pancreatic tumor cells. Here, we examined the expression level of Chmp1A in human RCC tissues and renal tumor cells by real-time quantitative RT-PCR and western blot. We found that the expression level of Chmp1A is significantly lower in RCC tissues and renal tumor cells compared with adjacent non-tumorous tissues and normal renal cells. Additionally, inhibition of Chmp1A expression by shRNA induced tumor formation in normal renal cells. However, inhibition of Chmp1A did not significantly affect tumor cell proliferation in vitro and tumor progression in vivo. Interestingly, overexpression of Chmp1A using a eukaryotic plasmid inhibited the proliferation of renal tumor cells in vitro and the growth of renal tumor in vivo. Thus, our results demonstrate that Chmp1A functions as a tumor suppressor gene in renal cells and may be a useful target for treatment of RCC.

Chromatin modifying protein 1A (Chmp1A) of the endosomal sorting complex required for transport (ESCRT)-III family activates ataxia telangiectasia mutated (ATM) for PanC-1 cell growth inhibition

Chromatin modifying protein 1A (Chmp1A) is a member of the Endosormal sorting complex required for transport (ESCRT)-III family whose over-expression induces growth inhibition, chromatin condensation, and p53 phosphorylation. p53 is a substrate for Ataxia telangiectasia mutated (ATM), which can be activated upon chromatin condensation. Thus, we propose that Chmp1A regulates ATM, and the nuclear localization signal (NLS) is required for ATM activation. Our data demonstrated that over-expression of full-length Chmp1A induced an increase in active, phosphorylated ATM in the nucleus, where they co-localized. It also induced an increase in phospho-p53 in the nucleus, and in vitro ATM kinase and p53 reporter activities. The intensity of phospho-p53 closely followed that of ectopically induced full-length Chmp1A, suggesting a tight correlation between Chmp1A over-expression and p53 phosphorylation. On the other hand, Chmp1A depletion (reported to promote cell growth) had minor effects on phospho-ATM and p53 expression compared to control, which had very little expression of these proteins. NLS-deleted cells showed uniform cytoplasmic-Chmp1A expression and acted like shRNA-expressing cells (cell growth promotion and minimal effect on ATM), demonstrating the significance of NLS on ATM activation and growth inhibition. C-deleted Chmp1A, detected in the cytoplasm at the enlarged vesicles, increased phospho-ATM and p53, and inhibited growth; yet it had no effect on in vitro ATM kinase or p53 reporter activities, suggesting that the C-domain is not required for ATM activation. Finally, ATM inactivation considerably reduced Chmp1A mediated growth inhibition and phosphorylation of p53, showing that Chmp1A regulates tumor growth partly through ATM signaling.

Adding a combination of hydroxycitrate and lipoic acid (METABLOC™) to chemotherapy improves effectiveness against tumor development: experimental results and case report

Altered metabolism of cancer first highlighted by Otto Warburg has a long history. Although ignored for a considerable amount of time, it is now receiving substantial attention. We recently published results obtained with a combination of two drugs, lipoic acid and hydroxycitrate, targeting metabolic enzymes particularly affected in cancer: ATP citrate lyase and pyruvate dehydrogenase kinase. This treatment was as efficient as chemotherapy in the three mouse cancer models that were tested. In this work, we asked if our drug combination could be used in conjunction with standard cytotoxic chemotherapy, in particular cisplatin, to improve basic protocol efficacy. A combination of lipoic acid and hydroxycitrate was administered to mice implanted with syngeneic cancer cells, LL/2 lung carcinoma and MBT-2 bladder carcinoma, concommitantly with classical chemotherapy (cisplatin or methotrexate). We demonstrate that the triple combination lipoic acid + hydroxycitrate + cisplatin or methotrexate is more efficient than cisplatin or methotrexate used individually or the combination of lipoic acid and hydroxycitrate administered alone. Of particular note are the results obtained in the treatment of an 80 year-old female who presented with ductal adenocarcinoma of the pancreas accompanied by liver metastases. A treatment course using gemcitabine plus α-lipoic acid and hydroxycitrate gave highly promising results. The in vivo data, coupled with the case study results, suggest a possible advantage in using a treatment targeted at cancer metabolism in association with classical chemotherapy.

Between death and survival: retinoic acid in regulation of apoptosis

The vitamin A metabolite all-trans-retinoic acid (RA) regulates multiple biological processes by virtue of its ability to regulate gene expression. It thus plays critical roles in embryonic development and is involved in regulating growth, remodeling, and metabolic responses in adult tissues. RA can also suppress carcinoma cell growth and is currently used in treatment of some cancers. Growth inhibition by RA may be exerted by induction of differentiation, cell cycle arrest, or apoptosis, or by a combination of these activities. Paradoxically, in the context of some cells, RA not only fails to inhibit growth but, instead, enhances proliferation and survival. This review focuses on the involvement of RA in regulating apoptotic responses. It includes brief overviews of transcriptional signaling by RA and of apoptotic pathways, and then addresses available information on the mechanisms by which RA induces apoptosis or, conversely, inhibits cell death and enhances survival.

Inhibitory effect of cucurbitacin E on pancreatic cancer cells growth via STAT3 signaling

PURPOSE

Pancreatic cancer has been a serious disease worldwide for its high mortality. Cucurbitacin E is a member of triterpenoid family isolated from plants showing antiproliferative activity on various cancer cells. In this study, we have explored whether cucurbitacin E also has an anti-tumor effect on pancreatic cancer cells.

METHODS

Human pancreatic cancer cells PANC-1 were used to explore the effect and possible mechanisms of cucurbitacin E on cell cycle progression, apoptosis and proliferation.

RESULTS

Cucurbitacin E has inhibited the growth of PANC-1 cells in a dose- and time-dependent manner, and has caused accumulation of cells at the G(2)/M phase as well as apoptosis. Western blotting also showed that cucurbitacin E treatment can inhibit STAT3 phosphorylation while upregulate p53 expression.

CONCLUSIONS

Our results suggested that cucurbitacin E may be an effective regimen for the chemotherapy of pancreatic cancer.