CARP-1/CCAR1: a biphasic regulator of cancer cell growth and apoptosis

ESF1 and MIPEP proteins promote estrogen receptor-positive breast cancer proliferation and are associated with patient prognosis

BACKGROUND

Estrogen receptor-positive (ER+) breast cancer accounts for two-thirds of all breast cancers, and its early and late recurrences still threaten patients' long-term survival and quality of life. Finding candidate tumor antigens and potential therapeutic targets is critical to addressing these unmet needs.

METHOD

The isobaric tags for relative and absolute quantitation (iTRAQ) proteomic analysis was employed to identify the differentially expressed proteins (DEPs) between ER + breast cancer and corresponding adjacent normal tissue. Candidate DEPs were screened by bioinformatic analyses, and their expression was confirmed by immunohistochemical (IHC) staining and western blot. A series of in vitro experiments, including wound healing assay, colony formation, and cell cycle assay, were performed to reveal the functions of selected DEPs. Additionally, their clinical significances were further analyzed.

RESULT

A total of 369 DEPs (fold change ≥ 2.0 or ≤ 0.66, P < 0.05) were discovered. Compared with normal tissue, 358 proteins were up-regulated and 11 proteins were down-regulated in ER + breast cancer. GO and KEGG enrichment analysis showed that DEPs were closely associated with RNA regulation and metabolic pathways. STRING analysis found ESF1 and MIPEP were the hub genes in breast cancer, whose increased expressions were verified by the IHC staining and western blot. Knocking down ESF1 and MIPEP inhibited colony formation and increased cell apoptosis. Besides, knocking down ESF1 inhibited wound healing but not MIPEP. In addition, ESF1 and MIPEP expression were negatively associated with patient prognosis.

CONCLUSION

The upregulation of ESF1 and MIPEP promoted ER + breast cancer proliferation, which might provide novel targets for the development of new therapies.

The splicing factor CCAR1 regulates the Fanconi anemia/BRCA pathway

The twenty-three Fanconi anemia (FA) proteins cooperate in the FA/BRCA pathway to repair DNA interstrand cross-links (ICLs). The cell division cycle and apoptosis regulator 1 (CCAR1) protein is also a regulator of ICL repair, though its possible function in the FA/BRCA pathway remains unknown. Here, we demonstrate that CCAR1 plays a unique upstream role in the FA/BRCA pathway and is required for FANCA protein expression in human cells. Interestingly, CCAR1 co-immunoprecipitates with FANCA pre-mRNA and is required for FANCA mRNA processing. Loss of CCAR1 results in retention of a poison exon in the FANCA transcript, thereby leading to reduced FANCA protein expression. A unique domain of CCAR1, the EF hand domain, is required for interaction with the U2AF heterodimer of the spliceosome and for excision of the poison exon. Taken together, CCAR1 is a splicing modulator required for normal splicing of the FANCA mRNA and other mRNAs involved in various cellular pathways.

CCAR1 promotes DNA repair via alternative splicing

DNA repair is directly performed by hundreds of core factors and indirectly regulated by thousands of others. We massively expanded a CRISPR inhibition and Cas9-editing screening system to discover factors indirectly modulating homology-directed repair (HDR) in the context of ∼18,000 individual gene knockdowns. We focused on CCAR1, a poorly understood gene that we found the depletion of reduced both HDR and interstrand crosslink repair, phenocopying the loss of the Fanconi anemia pathway. CCAR1 loss abrogated FANCA protein without substantial reduction in the level of its mRNA or that of other FA genes. We instead found that CCAR1 prevents inclusion of a poison exon in FANCA. Transcriptomic analysis revealed that the CCAR1 splicing modulatory activity is not limited to FANCA, and it instead regulates widespread changes in alternative splicing that would damage coding sequences in mouse and human cells. CCAR1 therefore has an unanticipated function as a splicing fidelity factor.

CCAR-1 works together with the U2AF large subunit UAF-1 to regulate alternative splicing

The Cell Division Cycle and Apoptosis Regulator (CCAR) protein family members have recently emerged as regulators of alternative splicing and transcription, as well as having other key physiological functions. For example, mammalian CCAR2/DBC1 forms a complex with the zinc factor protein ZNF326 to integrate alternative splicing with RNA polymerase II transcriptional elongation in AT-rich regions of the DNA. Additionally, Caenorhabditis elegans CCAR-1, a homolog to mammalian CCAR2, facilitates the alternative splicing of the perlecan unc-52 gene. However, much about the CCAR family's role in alternative splicing is unknown. Here, we have examined the role of CCAR-1 in genome-wide alternative splicing in Caenorhabditis elegans and have identified new alternative splicing targets of CCAR-1 using RNA sequencing. Also, we found that CCAR-1 interacts with the spliceosome factors UAF-1 and UAF-2 using mass spectrometry, and that knockdown of ccar-1 affects alternative splicing patterns, motility, and proteostasis of UAF-1 mutant worms. Collectively, we demonstrate the role of CCAR-1 in regulating global alternative splicing in C. elegans and in conjunction with UAF-1.

Uncovering key molecular mechanisms in the early and late-stage of papillary thyroid carcinoma using association rule mining algorithm

OBJECTIVE

Thyroid Cancer (TC) is the most frequent endocrine malignancy neoplasm. It is the sixth cause of cancer in women worldwide. The treatment process could be expedited by identifying the controlling molecular mechanisms at the early and late stages, which can contribute to the acceleration of treatment schemes and the improvement of patient survival outcomes. In this work, we study the significant mRNAs through Machine Learning Algorithms in both the early and late stages of Papillary Thyroid Cancer (PTC).

METHOD

During the course of our study, we investigated various methods and techniques to obtain suitable results. The sequence of procedures we followed included organizing data, using nested cross-validation, data cleaning, and normalization at the initial stage. Next, to apply feature selection, a t-test and binary Non-Dominated Sorting Genetic Algorithm II (NSGAII) were chosen to be employed. Later on, during the analysis stage, the discriminative power of the selected features was evaluated using machine learning and deep learning algorithms. Finally, we considered the selected features and utilized Association Rule Mining algorithm to identify the most important ones for improving the decoding of dominant molecular mechanisms in PTC through its early and late stages.

RESULT

The SVM classifier was able to distinguish between early and late-stage categories with an accuracy of 83.5% and an AUC of 0.78 based on the identified mRNAs. The most significant genes associated with the early and late stages of PTC were identified as (e.g., ZNF518B, DTD2, CCAR1) and (e.g., lnc-DNAJB6-7:7, RP11-484D2.3, MSL3P1), respectively.

CONCLUSION

Current study reveals a clear picture of the potential candidate genes that could play a major role not only in the early stage, but also throughout the late one. Hence, the findings could be of help to identify therapeutic targets for more effective PTC drug developments.

RAB11A and RAB11B control mitotic spindle function in intestinal epithelial progenitor cells

RAB11 small GTPases and associated recycling endosome have been localized to mitotic spindles and implicated in regulating mitosis. However, the physiological significance of such regulation has not been observed in mammalian tissues. We have used newly engineered mouse models to investigate intestinal epithelial renewal in the absence of single or double isoforms of RAB11 family members: Rab11a and Rab11b. Comparing with single knockouts, mice with compound ablation demonstrate a defective cell cycle entry and robust mitotic arrest followed by apoptosis, leading to a total penetrance of lethality within 3 days of gene ablation. Upon Rab11 deletion ex vivo, enteroids show abnormal mitotic spindle formation and cell death. Untargeted proteomic profiling of Rab11a and Rab11b immunoprecipitates has uncovered a shared interactome containing mitotic spindle microtubule regulators. Disrupting Rab11 alters kinesin motor KIF11 function and impairs bipolar spindle formation and cell division. These data demonstrate that RAB11A and RAB11B redundantly control mitotic spindle function and intestinal progenitor cell division, a mechanism that may be utilized to govern the homeostasis and renewal of other mammalian tissues.

Exploiting bioactive natural products of marine origin: Evaluation of the meroterpenoid metachromin V as a novel potential therapeutic drug for colorectal cancer

Colorectal cancer (CRC) is the second most common cause of cancer death, leading to almost 1 million deaths per year. Despite constant progress in surgical and therapeutic protocols, the 5-year survival rate of advanced CRC patients remains extremely poor. Colorectal Cancer Stem Cells (CRC-CSCs) are endowed with unique stemness-related properties responsible for resistance, relapse and metastasis. The development of novel therapeutics able to tackle CSCs while avoiding undesired toxicity is a major need for cancer treatment. Natural products are a large reservoir of unexplored compounds with possible anticancer bioactivity, sustainability, and safety. The family of meroterpenoids derived from sponges share interesting bioactive properties. Bioassay-guided fractionation of a meroterpenoids extract led to the isolation of three compounds, all cytotoxic against several cancer cell lines: Metachromins U, V and W. In this study, we evaluated the anticancer potential of the most active one, Metachromins V (MV), on patient-derived CRC-CSCs. MV strongly impairs CSCs-viability regardless their mutational background and the cytotoxic effect is maintained on therapy-resistant metastatic CSCs. MV affects cell cycle progression, inducing a block in G2 phase in all the cell lines tested and more pronouncedly in CRC-CSCs. Moreover, MV triggers an important reorganization of the cytoskeleton and a strong reduction of Rho GTPases expression, impairing CRC-CSCs motility and invasion ability. By Proteomic analysis identified a potential molecular target of MV: CCAR1, that regulates apoptosis under chemotherapy treatments and affect β-catenin pathway. Further studies will be needed to confirm and validate these data in in vivo experimental models.

A mass spectrometry-based approach for the identification of Kpnβ1 binding partners in cancer cells

Karyopherin beta 1 (Kpnβ1) is the principal nuclear importer of cargo proteins and plays a role in many cellular processes. Its expression is upregulated in cancer and essential for cancer cell viability, thus the identification of its binding partners might help in the discovery of anti-cancer therapeutic targets and cancer biomarkers. Herein, we applied immunoprecipitation coupled to mass spectrometry (IP-MS) to identify Kpnβ1 binding partners in normal and cancer cells. IP-MS identified 100 potential Kpnβ1 binding partners in non-cancer hTERT-RPE1, 179 in HeLa cervical cancer, 147 in WHCO5 oesophageal cancer and 176 in KYSE30 oesophageal cancer cells, including expected and novel interaction partners. 38 binding proteins were identified in all cell lines, with the majority involved in RNA metabolism. 18 binding proteins were unique to the cancer cells, with many involved in protein translation. Western blot analysis validated the interaction of known and novel binding partners with Kpnβ1 and revealed enriched interactions between Kpnβ1 and select proteins in cancer cells, including proteins involved in cancer development, such as Kpnα2, Ran, CRM1, CCAR1 and FUBP1. Together, this study shows that Kpnβ1 interacts with numerous proteins, and its enhanced interaction with certain proteins in cancer cells likely contributes to the cancer state.

Exploration of nuclear body-enhanced sumoylation reveals that PML represses 2-cell features of embryonic stem cells

Membrane-less organelles are condensates formed by phase separation whose functions often remain enigmatic. Upon oxidative stress, PML scaffolds Nuclear Bodies (NBs) to regulate senescence or metabolic adaptation. PML NBs recruit many partner proteins, but the actual biochemical mechanism underlying their pleiotropic functions remains elusive. Similarly, PML role in embryonic stem cell (ESC) and retro-element biology is unsettled. Here we demonstrate that PML is essential for oxidative stress-driven partner SUMO2/3 conjugation in mouse ESCs (mESCs) or leukemia, a process often followed by their poly-ubiquitination and degradation. Functionally, PML is required for stress responses in mESCs. Differential proteomics unravel the KAP1 complex as a PML NB-dependent SUMO2-target in arsenic-treated APL mice or mESCs. PML-driven KAP1 sumoylation enables activation of this key epigenetic repressor implicated in retro-element silencing. Accordingly, Pml^-/- mESCs re-express transposable elements and display 2-Cell-Like features, the latter enforced by PML-controlled SUMO2-conjugation of DPPA2. Thus, PML orchestrates mESC state by coordinating SUMO2-conjugation of different transcriptional regulators, raising new hypotheses about PML roles in cancer.

The Dysfunction of Carcinogenesis- and Apoptosis-Associated Genes that Develops in the Hypothalamus under Chronic Social Defeat Stress in Male Mice

Chronic social stress caused by daily agonistic interactions in male mice leads to a mixed anxiety/depression-like disorder that is accompanied by the development of psychogenic immunodeficiency and stimulation of oncogenic processes concurrently with many neurotranscriptomic changes in brain regions. The aim of the study was to identify carcinogenesis- and apoptosis-associated differentially expressed genes (DEGs) in the hypothalamus of male mice with depression-like symptoms and, for comparison, in aggressive male mice with positive social experience. To obtain two groups of animals with the opposite 20-day social experiences, a model of chronic social conflict was used. Analysis of RNA-Seq data revealed similar expression changes for many DEGs between the aggressive and depressed animals in comparison with the control group; however, the number of DEGs was significantly lower in the aggressive than in the depressed mice. It is likely that the observed unidirectional changes in the expression of carcinogenesis- and apoptosis-associated genes in the two experimental groups may be a result of prolonged social stress (of different severity) caused by the agonistic interactions. In addition, 26 DEGs were found that did not change expression in the aggressive animals and could be considered genes promoting carcinogenesis or inhibiting apoptosis. Akt1, Bag6, Foxp4, Mapk3, Mapk8, Nol3, Pdcd10, and Xiap were identified as genes whose expression most strongly correlated with the expression of other DEGs, suggesting that their protein products play a role in coordination of the neurotranscriptomic changes in the hypothalamus. Further research into functions of these genes may be useful for the development of pharmacotherapies for psychosomatic pathologies.

The expression level of mir-21-3p in platelet-rich plasma: A potential effective factor and predictive biomarker in recurrent implantation failure

Recurrent implantation failure (RIF) is the most important complication associated with in vitro fertilization (IVF). Despite the good quality of the transferred embryo, the success rate is rather disappointing. Therefore, predictive biomarkers for implantation are critical to making decisions about transferring high-quality embryos or cryopreserving them for cycles with a higher chance of implantation. Recently, intrauterine infusion of autologous platelet-rich plasma (PRP) has been proposed to increase the endometrial receptivity in RIF patients. PRP is rich in both growth factors and microRNAs (miRNAs). We investigated the possible association of mir-21-3p, mir-21-5p, mir-494-3p, mir-145-5p, and insulin-like growth factor-I (IGF-I) levels in PRP and platelet-poor plasma (PPP) samples with the pregnancy outcomes in RIF patients. The miRNA expression level and IGF-I concentration were assessed using real-time PCR and chemiluminescence methods respectively. Mir-21-3p was upregulated in PRP samples of the pregnant group in comparison to the nonpregnant group. There was no difference in the expression of mir-21-3p in PPP samples of these groups. The concentration of IGF-I was higher in PRP and PPP samples of the nonpregnant in comparison to the pregnant group. Receiver-operating characteristic curve analysis showed that mir-21-3p can be a valuable biomarker for the prediction of pregnancy chance in RIF patients treated with PRP.

Bone Marrow Mesenchymal Stem Cells (BMSCs)-Triggered Up-Regulation of miR-198 Impedes the Aggressive Migration and Invasion of Cervical Cancer Cells

As a subset of RNAs without protein-coding function, short non-coding RNAs (microRNAs) are reported to contribute to the progress of multiple disorders. Nevertheless, the precise function of miR-198 in human cervical cancer is still an open question. RNA sequencing between cervical cancer cell lines and normal cervical epithelial cells identified CCAR1 to be highly expressed in cervical cancer. Cells were transfected with si-CCAR1 followed by analysis of cell behaviors using clonogenic assay and transwell migrating assay. The binding of miR-198 and CCAR1 was verified by a dual-luciferase reporter gene experiment. CCAR1 was highly expressed in cervical cancer tissues and cell lines and associated with tumor staging. Knockdown of CCAR1 restrained the malignant phenotypes of cervical cancer cells. CCAR1 was a target of miR198. Co-culture with BMSCs upregulated miR-198 expression, resulting in impediment of the aggressive phenotypes of cervical cancer cells, which was mediated by suppression of CCAR1 and release of inflammatory factors. In conclusion, CCAR1 level is increased in cervical cancer tissues or cell lines. Co-culture of BMSCs can facilitate the proliferating, migrating and invading activities of cervical cancer cells but reduce the release of inflammatory factors which is possibly through manipulating the axis of miR-198/CCAR1.

Combined Transcriptomic and Proteomic Profiling to Unravel Osimertinib, CARP-1 Functional Mimetic (CFM 4.17) Formulation and Telmisartan Combo Treatment in NSCLC Tumor Xenografts

The epidermal growth factor receptor (EGFR) is highly expressed in many non-small cell lung cancers (NSCLC), necessitating the use of EGFR-tyrosine kinase inhibitors (TKIs) as first-line treatments. Osimertinib (OSM), a third-generation TKI, is routinely used in clinics, but T790M mutations in exon 20 of the EGFR receptor lead to resistance against OSM, necessitating the development of more effective therapeutics. Telmisartan (TLM), OSM, and cell cycle and apoptosis regulatory protein 1 (CARP-1) functional mimetic treatments (CFM4.17) were evaluated in this study against experimental H1975 tumor xenografts to ascertain their anti-cancer effects. Briefly, tumor growth was studied in H1975 xenografts in athymic nude mice, gene and protein expressions were analyzed using next-generation RNA sequencing, proteomics, RT-PCR, and Western blotting. TLM pre-treatment significantly reduced the tumor burden when combined with CFM-4.17 nanoformulation and OSM combination (TLM_CFM-F_OSM) than their respective single treatments or combination of OSM and TLM with CFM 4.17. Data from RNA sequencing and proteomics revealed that TLM_CFM-F_OSM decreased the expression of Lamin B2, STAT3, SOD, NFKB, MMP-1, TGF beta, Sox-2, and PD-L1 proteins while increasing the expression of AMPK proteins, which was also confirmed by RT-PCR, proteomics, and Western blotting. According to our findings, the TLM_CFM-F_OSM combination has a superior anti-cancer effect in the treatment of NSCLC by affecting multiple resistant markers that regulate mitochondrial homeostasis, inflammation, oxidative stress, and apoptosis.

Immune responses to CCAR1 and other dermatomyositis autoantigens are associated with attenuated cancer emergence

BACKGROUND

The temporal clustering of a cancer diagnosis with dermatomyositis (DM) onset is strikingly associated with autoantibodies against transcriptional intermediary factor 1-γ (TIF1-γ). Nevertheless, many patients with anti–TIF1-γ antibodies never develop cancer. We investigated whether additional autoantibodies are found in anti–TIF1-γ–positive patients without cancer.

METHODS

Using a proteomic approach, we defined 10 previously undescribed autoantibody specificities in 5 index anti–TIF1-γ–positive DM patients without cancer. These were subsequently examined in discovery (n = 110) and validation (n = 142) cohorts of DM patients with anti–TIF1-γ autoantibodies.

RESULTS

We identified 10 potentially novel autoantibodies in anti–TIF1-γ–positive DM patients, 6 with frequencies ranging from 3% to 32% in 2 independent DM cohorts. Autoantibodies recognizing cell division cycle and apoptosis regulator protein 1 (CCAR1) were the most frequent, and were significantly negatively associated with contemporaneous cancer (discovery cohort OR 0.27 [95% CI 0.7–1.00], P = 0.050; validation cohort OR 0.13 [95% CI 0.03–0.59], P = 0.008). When cancer did emerge, it occurred significantly later in anti-CCAR1–positive compared with anti-CCAR1–negative patients (median time from DM onset 4.3 vs. 0.85 years, respectively; P = 0.006). Cancers that emerged were more likely to be localized (89% of anti-CCAR1–positive cancers presenting at stage 0 or 1 compared with 42% of patients without anti-CCAR1 antibodies, P = 0.02). As the number of additional autoantibody specificities increased in anti–TIF1-γ–positive DM patients, the frequency of cancer decreased (P < 0.001).

CONCLUSION

As the diversity of immune responses in anti–TIF1-γ DM patients increases, the likelihood of cancer emerging decreases. Our findings have important relevance for cancer risk stratification in DM patients and for understanding natural immune regulation of cancer in humans.

TRIAL REGISTRATION

Not applicable.

FUNDING SOURCES

The NIH, the Donald B. and Dorothy L. Stabler Foundation, and the Huayi and Siuling Zhang Discovery Fund.

Targeting multiple genes containing long mononucleotide A-T repeats in lung cancer stem cells

BACKGROUND

Intratumour heterogeneous gene expression among cancer and cancer stem cells (CSCs) can cause failure of current targeted therapies because each drug aims to target the function of a single gene. Long mononucleotide A-T repeats are cis-regulatory transcriptional elements that control many genes, increasing the expression of numerous genes in various cancers, including lung cancer. Therefore, targeting A-T repeats may dysregulate many genes driving cancer development. Here, we tested a peptide nucleic acid (PNA) oligo containing a long A-repeat sequence [A(15)] to disrupt the transcriptional control of the A-T repeat in lung cancer and CSCs.

METHODS

First, we separated CSCs from parental lung cancer cell lines. Then, we evaluated the role of A-T repeat gene regulation by counting the number of repeats in differentially regulated genes between CSCs and the parental cells of the CSCs. After testing the dosage and effect of PNA-A15 on normal and cancer cell toxicity and CSC phenotypes, we analysed genome-wide expression to identify dysregulated genes in CSCs.

RESULTS

The number of A-T repeats in genes differentially regulated between CSCs and parental cells differed. PNA-A15 was toxic to lung cancer cells and CSCs but not to noncancer cells. Finally, PNA-A15 dysregulated a number of genes in lung CSCs.

CONCLUSION

PNA-A15 is a promising novel targeted therapy agent that targets the transcriptional control activity of multiple genes in lung CSCs.

Role of nano-lipid formulation of CARP-1 mimetic, CFM-4.17 to improve systemic exposure and response in osimertinib resistant non-small cell lung cancer

BACKGROUND

EGFR mutated NSCLCs have been shown to employ the use of CARP-1 in overriding the signaling inhibition of tyrosine kinase inhibitors (such as Osimertinib). CFM 4.17 is a CARP-1 inhibitor which has a promising role in overcoming Tyrosine Kinase Inhibitor (TKI) resistance when used as a pre-treatment through promoting apoptosis. Lack of solubility, hydrophobicity leading to poor systemic exposure are the limitations of CFM 4.17. This can be overcome by nano lipid-based formulation (NLPF) of CFM 4.17 which can enhance systemic exposure in preclinical animal models as well as improve therapeutic efficacy in drug-resistant cancer cell lines.

METHODS

Molecular docking simulation studies were performed for CFM 4.17. CFM 4.17-NLPF was formulated by melt dispersion technique and optimized using a Box-Behnken designed surface response methodology approach using Design Expert and MATLAB. In vitro, CFM 4.17 release studies were performed in simulated gastric fluids (SGF-pH-1.2) and simulated intestinal fluids (SIF- pH-6.8). Cell viability assays were performed with HCC827 and H1975 Osimertinib resistant and non-resistant cells in 2D and 3D culture models of Non-small cell lung cancer to determine the effects of CFM 4.17 pre-treatment in Osimertinib response. In vivo pharmacokinetics in rats were performed measuring the effects of NLPF on CFM 4.17 to improve the systemic exposure.

RESULTS

CFM 4.17 was well accommodated in the active pocket of the active site of human EGFR tyrosine kinase. CFM 4.17 NLPF was optimized with robust experimental design with particle size less than 300 nm and % entrapment efficiency of 92.3 ± 1.23. Sustained diffusion-based release of CFM 4.17 was observed from NLPF in SGF and SIFs with Peppas and Higuchi based release kinetics, respectively. CFM 4.17 pretreatment improved response by decreasing IC50 value by 2-fold when compared to single treatment Osimertinib in both 2D monolayer and 3D spheroid assays in HCC827 and H1975 Osimertinib resistant and non-resistant cells of Non-small cell lung cancer. There were no differences between CFM 4.17 NLPF and suspension in 2D monolayer culture pretreatments; however, The 3D culture assays showed that CFM 4.17 NLPF improved combination sensitivity. Pharmacokinetic analysis showed that CFM 4.17 NLPF displayed higher AUCtot (2.9-fold) and Cmax (1.18-fold) as compared to free CFM 4.17. In contrast, the animal groups administered CFM 4.17 NLPF showed a 4.73-fold (in half-life) and a 3.07-fold increase (in MRT) when compared to equivalent dosed suspension.

CONCLUSION

We have successfully formulated CFM 4.17 NLPFs by robust RSM design approach displaying improved response through sensitizing cells to Osimertinib treatment as well as improving the oral bioavailability of CFM 4.17.

CCAR1 and CCAR2 as gene chameleons with antagonistic duality: Preclinical, human translational, and mechanistic basis

Cell Cycle and Apoptosis Regulator 1 (CCAR1) and Cell Cycle and Apoptosis Regulator 2 (CCAR2) have emerged as key players in physiology and pathophysiology, with critical roles in the DNA damage response, nuclear receptor function, and Wnt signaling, among other activities. Contradictory reports exist on the functional duality of CCAR1 and CCAR2 as either tumor promoters or suppressors, suggesting that CCAR1 and CCAR2 have the hallmarks of gene chameleons. We review herein the mechanistic, preclinical, and human translational findings for CCAR1 and CCAR2, based on available RNA and protein expression data from human studies, The Cancer Genome Atlas (TCGA) data mining, gene knockout mouse models, and cell-based assays. Multiple factors contribute to the divergent activities of CCAR1 and CCAR2, including tissue type, mutation/genetic background, protein-protein interactions, dynamic regulation via posttranslational modifications, and alternative RNA splicing. An array of protein partners interact with CCAR1 and CCAR2 in the context of tumor promotion and suppression, including β-catenin, androgen receptor, p21Cip1/Waf1, tumor protein p53 (p53), sirtuin 1, and histone deacetylase 3. Genetic changes frequently found in cancer, such as TP53 mutation, also serve as critical determinants of survival outcomes in cancer patients. This review seeks to provide the impetus for further investigation into CCAR1 and CCAR2 as potential master regulators of metabolism, aging, and cancer.

The roles of circRNAs in cancers: Perspectives from molecular functions

Circular RNAs (circRNAs), characteristic of covalently closed loops generated by back-splicing, are a subclass of single-stranded RNA molecules. Owing to the circular structures, circRNAs are protected from exonuclease-induced degradation, which makes them more stable compared with linear RNAs. With the development of high-throughput sequencing technology and bioinformatics, the roles of circRNAs in a variety of physiological and pathophysiological processes have been increasingly revealed. Although the functions of most circRNAs remain largely elusive, accumulating studies have identified them as microRNA(miRNA) sponges, protein regulators, transcriptional regulators, protein templates, and so forth. In this review, we briefly describe the biogenesis of circRNAs and provide an overview on their functions in cancers, including miRNA sponges, protein regulators, transcriptional regulators, protein templates. Furthermore, we discuss the potential application of circRNAs as biomarkers and give insight into future perspectives.

The identification of nuclear αvβ3 integrin in ovarian cancer: non-paradigmal localization with cancer promoting actions

Nuclear translocation of transmembrane proteins was reported in high-grade serous ovarian cancer (HGSOC), a highly aggressive gynecological malignancy. Although the membrane receptor αvβ3 integrin is amply expressed in HGSOC and involved in disease progression, its nuclear localization was never demonstrated. Nuclear αvβ3 was explored in HGSOC cells (OVCAR3, KURAMOCHI, and JHOS4), nuclear localization signal (NLS) modified β3 OVCAR3, Chinese hamster ovaries (CHO-K1) and human embryonic kidney (HEK293) before/after transfections with β3/β1 integrins. We used the ImageStream technology, Western blots (WB), co immunoprecipitations (Co-IP), confocal immunofluorescence (IF) microscopy, flow cytometry for cell counts and cell cycle, wound healing assays and proteomics analyses. Fresh/archived tumor tissues were collected from nine HGSOC patients and normal ovarian and fallopian tube (FT) tissues from eight nononcological patients and assessed for nuclear αvβ3 by WB, confocal IF microscopy and immunohistochemistry (IHC). We identified nuclear αvβ3 in HGSOC cells and tissues, but not in normal ovaries and FTs. The nuclear integrin was Tyr 759 phosphorylated and functionally active. Nuclear αvβ3 enriched OVCAR3 cells demonstrated induced proliferation and oncogenic signaling, intact colony formation ability and inhibited migration. Proteomics analyses revealed a network of nuclear αvβ3-bound proteins, many of which with key cancer-relevant activities. Identification of atypical nuclear localization of the αvβ3 integrin in HGSOC challenges the prevalent conception that the setting in which this receptor exerts its pleiotropic actions is exclusively at the cell membrane. This discovery proposes αvβ3 moonlighting functions and may improve our understanding of the molecular basis of ovarian cancer pathogenesis.

Novel strategies to target chemoresistant triple-negative breast cancer

Previous studies from our group and others have shown that current drug treatment(s) strategies eliminate bulk of tumor cells (non-CSCs) but it had a minimal effect on cancer stem cells (CSCs) leading to resistance and tumor recurrence. We studied the effects of CFM-4.16 (CARP-1 functional mimetic) and/or cisplatin on four Triple-negative breast cancer (TNBC) MDA-MB-468, MDA-MB-231, CRL-2335 and BR-1126, two cisplatin resistant CisR/MDA-231 and CisR/MDA-468 and cancer stem cells (CSCs) from resistant cell lines. TNBC cells treated with CFM-4.16 plus cisplatin inhibited the expression of FZD8, LRP6 and c-Myc and significantly enhanced cell death in all the cell lines by ~70%-80% compared with the control(s). When Cisplatin resistant CisR/MDA-231 and CisR/MDA-468 were treated with CFM-4.16 plus cisplatin, they also showed a reduction in FZD8 and LRP6 and increased apoptosis compared to control group. Similarly, CFM-4.16 plus cisplatin treatment reduced mammospheres formation abilities of CSCs by 80-90% compared to control group, increased PARP cleavage and apoptosis. Data shows CFM-4.16 plus cisplatin treatment significantly increased apoptosis/cell death in parental, cisplatin resistant and CSCs. Taken together the data suggests that FZD8-mediated Wnt-signaling plays a major role in mediating CSCs growth and resistance to chemotherapy and its inhibition enhances the chemotherapeutic response in TNBC.

Baoyuan decoction ameliorates apoptosis via AT1-CARP signaling pathway in H9C2 cells and heart failure post-acute myocardial infarction rats

ETHNOPHARMACOLOGICAL RELEVANCE

Previous studies have approved that Baoyuan decoction (BYD) exerted remarkable cardioprotective effects on heart failure (HF) due to its anti-apoptotic properties. As a novel biomarker and target of HF, Cardiac ankyrin repeat protein (CARP) can exacerbate apoptosis via activation by angiotensin type 1 receptor (AT1) and subsequently deteriorate heart function. Transcriptome results in our previous study indicated BYD was beneficial to HF post-acute myocardial infarction (AMI) with a promising effect on CARP. However, the mechanism remains to be validated.

AIM OF THE STUDY

This study aims to elucidate whether BYD ameliorates apoptosis to protect against HF via AT1-CARP signaling pathway.

MATERIALS AND METHODS

Left anterior descending ligation was applied to induce an HF rat model, Ang Ⅱ-stimulated H9C2 cells apoptotic model and overexpression of Ankrd1/CARP H9C2 cells were established to clarify the effects and potential mechanism of BYD. Ethanol extracts of BYD (0.64; 1.28; 2.57 g/kg) were orally administered for four weeks and Fosinopril (4.67 mg/kg) was selected as a positive group in vivo. In vitro, BYD (400, 600, 800 μg/ml) or RNH6270 (an inhibitor of AT1, 1 μM) was co-cultured with Ang Ⅱ stimulation for 48 h in H9C2 cells. Overexpression of Ankrd1/CARP was conducted by transient transfection with H9C2 cells to further confirm the exact mechanism. Finally, to define the active ingredients of anti-cardiomyocyte apoptosis in BYD, we furtherly used the Ang Ⅱ-induced cardiomyocyte apoptosis model to evaluate the effects.

RESULTS

Echocardiography and TUNEL results showed that BYD in different doses remarkably improved heart function and inhibited apoptosis in vivo. Further study demonstrated that AT1 and CARP expressions in cardiac tissue were suppressed by BYD, accompanied with upregulation of B cell lymphoma-2 (Bcl-2) and downregulation of several pro-apoptotic molecules, including p53, Bcl-2 Associated X Protein (Bax) and Cleaved caspase 3. In parallel with the vivo experiment, in vitro research indicated BYD dramatically reduced the apoptotic cells and regulated expressions of critical apoptosis-related molecules mediated through downregulation of AT1 and CARP simultaneously which were consistent with the results in vivo experiment. Transiently transfected CARP over-expression further confirmed that BYD could suppress severe cardiomyocytes apoptosis induced by overexpression of CARP. Especially, the active ingredients of BYD including Astragaloside IV, Ginsenoside Rg3, Rb1, Rc and Re showed significantly anti-apoptosis effects.

CONCLUSION

BYD improves cardiac function and protects against cardiomyocytes injury by inhibiting apoptosis via regulating the AT1-CARP signaling pathway.

Circular RNAs negatively regulate cancer stem cells by physically binding FMRP against CCAR1 complex in hepatocellular carcinoma

Circular RNA (circRNA) possesses great pre-clinical diagnostic and therapeutic potentials in multiple cancers. It has been reported playing roles in multiple malignant behaviors including proliferation, migration, metastasis and chemoresistance. However, the underlying correlation between circRNAs and cancer stem cells (CSCs) has not been reported yet.

Methods: circZKSCAN1 level was detected in HCC tissue microarrays to clarify its prognostic values. Gain and loss function experiments were applied to investigate the role of circZKSCAN1 in HCC stemness. Bioinformatic analysis was used to predict the possible downstream RNA binding protein and further RNA immunoprecipitation sequencing was carried out to identify the RBP-regulated genes.

Results: The absence of circZKSCAN1 endowed several malignant properties including cancer stemness and tightly correlated with worse overall and recurrence-free survival rate in HCC. Bioinformatics analysis and RNA immunoprecipitation-sequencing (RIP-seq) results revealed that circZKSCAN1 exerted its inhibitive role by competitively binding FMRP, therefore, block the binding between FMRP and β-catenin-binding protein-cell cycle and apoptosis regulator 1 (CCAR1) mRNA, and subsequently restrain the transcriptional activity of Wnt signaling. In addition, RNA-splicing protein Quaking 5 was found downregulated in HCC tissues and responsible for the reduction of circZKSCAN1.

Conclusion: Collectively, this study revealed the mechanisms underlying the regulatory role of circZKSCAN1 in HCC CSCs and identified the newly discovered Qki5-circZKSCAN1-FMRP-CCAR1-Wnt signaling axis as a potentially important therapeutic target for HCC treatment.

Inhibition of histone deacetylase 11 promotes human liver cancer cell apoptosis

The apoptosis machinery is compromised in liver cancer (LC). The underlying mechanism needs to be further investigated. Histone deacetylases (HDAC) have multiple and strong biochemical activities. This study tests a hypothesis that HDAC11 prevents LC cell (LCC) apoptosis via modulating the p53 gene transcription. In this study, the LC tissues were collected from patients with LC. The LCCs were purified by magnetic cell sorting. The gene transcription activities of the LCCs were analyzed by immunoprecipitation (IP) and chromatin IP. We observed that the LCCs expressed high levels of HDAC11, which was negatively correlated with the expression of p53 in LCCs. Further findings indicated that HDAC11 formed a complex with Egr1, the transcription factor of p53. HDAC11 induced Egr1 deacetylation and thus prevented the p53 gene transcription. Over expression of HDAC11 in liver cells inhibited the cell apoptosis. Inhibition of the expression of HDAC11 in LCCs promoted the LCC apoptosis. In conclusion, HDAC11 plays a critical role in the compromising the expression p53 in LCC, which can be reversed by the inhibition of HDAC11. To regulate HDAC11 may have therapeutic potential for LC treatment.

A H2AX⁻CARP-1 Interaction Regulates Apoptosis Signaling Following DNA Damage

Cell Cycle and Apoptosis Regulatory Protein (CARP-1/CCAR1) is a peri-nuclear phosphoprotein that regulates apoptosis via chemotherapeutic Adriamycin (doxorubicin) and a novel class of CARP-1 functional mimetic (CFM) compounds. Although Adriamycin causes DNA damage, data from Comet assays revealed that CFM-4.16 also induced DNA damage. Phosphorylation of histone 2AX (γH2AX) protein is involved in regulating DNA damage repair and apoptosis signaling. Adriamycin or CFM-4.16 treatments inhibited cell growth and caused elevated CARP-1 and γH2AX in human breast (HBC) and cervical cancer (HeLa) cells. In fact, a robust nuclear or peri-nuclear co-localization of CARP-1 and γH2AX occurred in cells undergoing apoptosis. Knock-down of CARP-1 diminished γH2AX, their co-localization, and apoptosis in CFM-4.16- or Adriamycin-treated cells. We found that CARP-1 directly binds with H2AX, and H2AX interacted with CARP-1, but not CARP-1 (Δ600–652) mutant. Moreover, cells expressing CARP-1 (Δ600–652) mutant were resistant to apoptosis, and had diminished levels of γH2AX, when compared with cells expressing wild-type CARP-1. Mutagenesis studies revealed that H2AX residues 1–35 harbored a CARP-1-binding epitope, while CARP-1 amino acids 636–650 contained an H2AX-interacting epitope. Surface plasmon resonance studies revealed that CARP-1 (636–650) peptide bound with H2AX (1–35) peptide with a dissociation constant (K_d) of 127 nM. Cells expressing enhanced GFP (EGFP)-tagged H2AX (1–35) peptide or EGFP-tagged CARP-1 (636–650) peptide were resistant to inhibition by Adriamycin or CFM-4.16. Treatment of cells with transactivator of transcription (TAT)-tagged CARP-1 (636–650) peptide resulted in a moderate, statistically significant abrogation of Adriamycin-induced growth inhibition of cancer cells. Our studies provide evidence for requirement of CARP-1 interaction with H2AX in apoptosis signaling by Adriamycin and CFM compounds.

Tumor hypoxia directed multimodal nanotherapy for overcoming drug resistance in renal cell carcinoma and reprogramming macrophages

Drug resistance is one of the significant clinical burden in renal cell carcinoma (RCC). The development of drug resistance is attributed to many factors, including impairment of apoptosis, elevation of carbonic anhydrase IX (CA IX, a marker of tumor hypoxia), and infiltration of tumorigenic immune cells. To alleviate the drug resistance, we have used Sorafenib (Sor) in combination with tumor hypoxia directed nanoparticle (NP) loaded with a new class of apoptosis inducer, CFM 4.16 (C4.16), namely CA IX-C4.16. The NP is designed to selectively deliver the payload to the hypoxic tumor (core), provoke superior cell death in parental (WT) and Everolimus-resistant (Evr-res) RCC and selectively downmodulate tumorigenic M2-macrophage. Copper-free 'click' chemistry was utilized for conjugating SMA-TPGS with Acetazolamide (ATZ, a CA IX-specific targeting ligand). The NP was further tagged with a clinically approved NIR dye (S0456) for evaluating hypoxic tumor core penetration and organ distribution. Imaging of tumor spheroid treated with NIR dye-labeled CA IX-SMA-TPGS revealed remarkable tumor core penetration that was modulated by CA IX-mediated targeting in hypoxic-A498 RCC cells. The significant cell killing effect with synergistic combination index (CI) of CA IX-C4.16 and Sor treatment suggests efficient reversal of Evr-resistance in A498 cells. The CA IX directed nanoplatform in combination with Sor has shown multiple benefits in overcoming drug resistance through (i) inhibition of p-AKT, (ii) upregulation of tumoricidal M1 macrophages resulting in induction of caspase 3/7 mediated apoptosis of Evr-res A498 cells in macrophage-RCC co-culturing condition, (iii) significant in vitro and in vivo Evr-res A498 tumor growth inhibition as compared to individual therapy, and (iv) untraceable liver and kidney toxicity in mice. Near-infrared (NIR) imaging of CA IX-SMA-TPGS-S0456 in Evr-res A498 RCC model exhibited significant accumulation of CA IX-oligomer in tumor core with >3-fold higher tumor uptake as compared to control. In conclusion, this proof-of-concept study demonstrates versatile tumor hypoxia directed nanoplatform that can work in synergy with existing drugs for reversing drug-resistance in RCC accompanied with re-education of tumor-associated macrophages, that could be applied universally for several hypoxic tumors.

Potential Applications of Nanotechnology in Urological Cancer

Nowadays, the potential scope of nanotechnology in uro-oncology (cancers of the prostate, bladder, and kidney) is broad, ranging from drug delivery, prevention, and diagnosis to treatment. Novel drug delivery methods using magnetic nanoparticles, gold nanoparticles, and polymeric nanoparticles have been investigated in prostate cancer. Additionally, renal cancer treatment may be profoundly influenced by applications of nanotechnology principles. Various nanoparticle-based strategies for kidney cancer therapy have been proposed. Partly due to the dilution of drug concentrations by urine production, causing inadequate drug delivery to tumor cells in the treatment of bladder cancer, various multifunctional bladder-targeted nanoparticles have been developed to enhance therapeutic efficiency. In each of these cancer research fields, nanotechnology has shown several advantages over widely used traditional methods. Different types of nanoparticles improve the solubility of poorly soluble drugs, and multifunctional nanoparticles have good specificity toward prostate, renal, and bladder cancer. Moreover, nanotechnology can also combine with other novel technologies to further enhance effectivity. As our understanding of nanotechnologies grows, additional opportunities to improve the diagnosis and treatment of urological cancer are excepted to arise. In this review, we focus on nanotechnologies with potential applications in urological cancer therapy and highlight clinical areas that would benefit from nanoparticle therapy.

A CARP-1 functional mimetic compound is synergistic with BRAF-targeting in non-small cell lung cancers

Non-small cell lung cancers (NSCLC) account for 85% of all lung cancers, and the epidermal growth factor receptor (EGFR) is highly expressed or activated in many NSCLC that permit use of EGFR tyrosine kinase inhibitors (TKIs) as frontline therapies. Resistance to EGFR TKIs eventually develops that necessitates development of improved and effective therapeutics. CARP-1/CCAR1 is an effector of apoptosis by Doxorubicin, Etoposide, or Gefitinib, while CARP-1 functional mimetic (CFM) compounds bind with CARP-1, and stimulate CARP-1 expression and apoptosis. To test whether CFMs would inhibit TKI-resistant NSCLCs, we first generated and characterized TKI-resistant NSCLC cells. The GI₅₀ dose of Erlotinib for parental and Erlotinib-resistant HCC827 cells was ∼0.1 μM and ≥15 μM, respectively. While Rociletinib or Ocimertinib inhibited the parental H1975 cells with GI₅₀ doses of ≤0.18 μM, the Ocimertinib-resistant pools of H1975 cells had a GI₅₀ dose of ∼12 μM. The GI₅₀ dose for Rociletinib-resistant H1975 sublines ranged from 4.5-8.0 μM. CFM-4 and its novel analog CFM-4.16 attenuated growth of the parental and TKI-resistant NSCLC cells. CFMs activated p38/JNKs, inhibited oncogenic cMet and Akt kinases, while CARP-1 depletion blocked NSCLC cell growth inhibition by CFM-4.16 or Erlotinib. CFM-4.16 was synergistic with B-Raf-targeting in NSCLC, triple-negative breast cancer, and renal cancer cells. A nano-lipid formulation (NLF) of CFM-4.16 in combination with Sorafenib elicited a superior growth inhibition of xenografted tumors derived from Rociletinib-resistant H1975 NSCLC cells in part by stimulating CARP-1 and apoptosis. These findings support therapeutic potential of CFM-4.16 together with B-Raf targeting in treatment of TKI-resistant NSCLCs.

CCAR-1 affects hemidesmosome biogenesis by regulating unc-52/perlecan alternative splicing in the C. elegans epidermis

Hemidesmosomes are epithelial-specific attachment structures that maintain tissue integrity and resist tension. Despite their importance, how hemidesmosomes are regulated at the post-transcriptional level is poorly understood. Caenorhabditiselegans hemidesmosomes (CeHDs) have a similar structure and composition to their mammalian counterparts, making C. elegans an ideal model for studying hemidesmosomes. Here, we focus on the transcription regulator CCAR-1, identified in a previous genetic screen searching for enhancers of mutations in the conserved hemidesmosome component VAB-10A (known as plectin in mammals). Loss of CCAR-1 function in a vab-10(e698) background results in CeHD disruption and muscle detachment from the epidermis. CCAR-1 regulates CeHD biogenesis, not by controlling the transcription of CeHD-related genes, but by affecting the alternative splicing of unc-52 (known as perlecan or HSPG2 in mammals), the predicted basement extracellular matrix (ECM) ligand of CeHDs. CCAR-1 physically interacts with HRP-2 (hnRNPR in mammals), a splicing factor known to mediate unc-52 alternative splicing to control the proportions of different UNC-52 isoforms and stabilize CeHDs. Our discovery underlines the importance of post-transcriptional regulation in hemidesmosome reorganization. It also uncovers previously unappreciated roles of CCAR-1 in alternative splicing and hemidesmosome biogenesis, shedding new light on the mechanisms through which mammalian CCAR1 functions in tumorigenesis.

Delineating the HMGB1 and HMGB2 interactome in prostate and ovary epithelial cells and its relationship with cancer

High Mobility Group B (HMGB) proteins are involved in cancer progression and in cellular responses to platinum compounds used in the chemotherapy of prostate and ovary cancer. Here we use affinity purification coupled to mass spectrometry (MS) and yeast two-hybrid (Y2H) screening to carry out an exhaustive study of HMGB1 and HMGB2 protein interactions in the context of prostate and ovary epithelia. We present a proteomic study of HMGB1 partners based on immunoprecipitation of HMGB1 from a non-cancerous prostate epithelial cell line. In addition, HMGB1 and HMGB2 were used as baits in yeast two-hybrid screening of libraries from prostate and ovary epithelial cell lines as well as from healthy ovary tissue. HMGB1 interacts with many nuclear proteins that control gene expression, but also with proteins that form part of the cytoskeleton, cell-adhesion structures and others involved in intracellular protein translocation, cellular migration, secretion, apoptosis and cell survival. HMGB2 interacts with proteins involved in apoptosis, cell motility and cellular proliferation. High confidence interactors, based on repeated identification in different cell types or in both MS and Y2H approaches, are discussed in relation to cancer. This study represents a useful resource for detailed investigation of the role of HMGB1 in cancer of epithelial origins, as well as potential alternative avenues of therapeutic intervention.

A Comprehensive Pan-Cancer Molecular Study of Gynecologic and Breast Cancers

We analyzed molecular data on 2,579 tumors from The Cancer Genome Atlas (TCGA) of four gynecological types plus breast. Our aims were to identify shared and unique molecular features, clinically significant subtypes, and potential therapeutic targets. We found 61 somatic copy-number alterations (SCNAs) and 46 significantly mutated genes (SMGs). Eleven SCNAs and 11 SMGs had not been identified in previous TCGA studies of the individual tumor types. We found functionally significant estrogen receptor-regulated long non-coding RNAs (lncRNAs) and gene/lncRNA interaction networks. Pathway analysis identified subtypes with high leukocyte infiltration, raising potential implications for immunotherapy. Using 16 key molecular features, we identified five prognostic subtypes and developed a decision tree that classified patients into the subtypes based on just six features that are assessable in clinical laboratories.

CARP-1 functional mimetics are novel inhibitors of drug-resistant triple negative breast cancers

Doxorubicin and Cisplatin are the frontline therapeutics for treatment of the triple negative breast cancers (TNBCs). Emergence of drug-resistance often contributes to failure of drugs and poor prognosis, and thus necessitates development of new and improved modalities to treat TNBCs. We generated and characterized chemotherapy-resistant TNBC cells following their culture in chronic presence of Doxorubicin or Cisplatin, and tested whether their viabilities were inhibited by a novel class of CARP- 1 functional mimetic (CFM) compounds. Analogs of parent compound CFM-4 were obtained through structure-activity based medicinal chemistry studies. CFM-4.16, a novel analog of CFM-4, caused superior inhibition of viability of TNBC cells when used in combination with doxorubicin. Doxorubicin and cisplatin inhibited viabilities of parental cells with GI₅₀ dose of 0.02–0.1 μM and 1.65 μM, respectively. The GI₅₀ dose of doxorubicin for doxorubicin-resistant TNBC cells was ≥ 10.0 μM. For Cisplatin-resistant cells, the GI₅₀ dose of Cisplatin was ≥ 6–15.0 μM for MDA-MB-468 sublines and ≥ 150.0 μM for MDA-MB-231 sublines. CFM-4.16 inhibited viability of chemotherapy-resistant TNBC cells, in part by inhibiting oncogenic cMet activation and expression, stimulating CARP-1 expression, caspase-8 cleavage and apoptosis. CFM-4.16 pretreatment enhanced anti-TNBC efficacies of inhibitors of cMET (Tevatinib) or cSrc (Dasatinib). CFM-4.16 suppressed growth of resistant TNBC cells in soft agar as well as in three-dimensional suspension cultures derived from enriched, stem-like cells. Finally, a nanolipid formulation of CFM-4.16 in combination with doxorubicin had superior efficacy in inhibiting TNBC xenograft growth. Our findings collectively demonstrate therapeutic potential of CFM-4.16 for parental and drug-resistant TNBCs.

A CARP-1 functional mimetic loaded vitamin E-TPGS micellar nano-formulation for inhibition of renal cell carcinoma

Current treatments for Renal Cell Carcinoma (RCC) include a combination of surgery, targeted therapy, and immunotherapy. Emergence of resistant RCCs contributes to failure of drugs and poor prognosis, and thus warrants development of new and improved treatment options for RCCs. Here we generated and characterized RCC cells that are resistant to Everolimus, a frontline mToR-targeted therapy, and tested whether our novel class of CARP-1 functional mimetic (CFM) compounds inhibit parental and Everolimus-resistant RCC cells. CFMs inhibited RCC cell viability in a dose-dependent manner that was comparable to Everolimus treatments. The GI₅₀ dose of Everolimus for parental A498 cells was ∼1.2μM while it was <0.02μM for the parental UOK262 and UOK268 cells. The GI₅₀ dose for Everolimus-resistant A498, UOK262, and UOK268 cells were ≥10.0μM, 1.8-7.0μM, and 7.0-≥10.0μM, respectively. CFM-4 and its novel analog CFM-4.16 inhibited viabilities of Everolimus resistant RCC cells albeit CFM-4.16 was more effective than CFM-4. CFM-dependent loss of RCC cell viabilities was due in part to reduced cyclin B1 levels, activation of pro-apoptotic, stress-activated protein kinases (SAPKs), and apoptosis. CFM-4.16 suppressed growth of resistant RCC cells in three-dimensional suspension cultures. However, CFMs are hydrophobic and their intravenous administration and dose escalation for in-vivo studies remain challenging. In this study, we encapsulated CFM-4.16 in Vitamin-E TPGS-based- nanomicelles that resulted in its water-soluble formulation with higher CFM-4.16 loading (30% w/w). This CFM-4.16 formulation inhibited viability of parental and Everolimus-resistant RCC cells in vitro, and suppressed growth of parental A498 RCC-cell-derived xenografts in part by stimulating apoptosis. These findings portent promising therapeutic potential of CFM-4.16 for treatment of RCCs.

4β-Hydroxywithanolide E Modulates Alternative Splicing of Apoptotic Genes in Human Hepatocellular Carcinoma Huh-7 Cells

Alternative splicing is a mechanism for increasing protein diversity from a limited number of genes. Studies have demonstrated that aberrant regulation in the alternative splicing of apoptotic gene transcripts may contribute to the development of cancer. In this study, we isolated 4β-Hydroxywithanolide E (4bHWE) from the traditional herb Physalis peruviana and investigated its biological effect in cancer cells. The results demonstrated that 4bHWE modulates the alternative splicing of various apoptotic genes, including HIPK3, SMAC/DIABLO, and SURVIVIN. We also discovered that the levels of SRSF1 phospho-isoform were decreased and the levels of H3K36me3 were increased in 4bHWE treatment. Knockdown experiments revealed that the splicing site selection of SMAC/DIABLO could be mediated by changes in the level of H3K36me3 in 4bHWE-treated cells. Furthermore, we extended our study to apoptosis-associated molecules, and detected increased levels of poly ADP-ribose polymerase cleavage and the active form of CASPASE-3 in 4bHWE-induced apoptosis. In vivo experiments indicated that the treatment of tumor-bearing mice with 4bHWE resulted in a marked decrease in tumor size. This study is the first to demonstrate that 4bHWE affects alternative splicing by modulating splicing factors and histone modifications, and provides a novel view of the antitumor mechanism of 4bHWE.

Increased MIR31HG lncRNA expression increases gefitinib resistance in non-small cell lung cancer cell lines through the EGFR/PI3K/AKT signaling pathway

The aim of the present study was to gain insight into the molecular mechanism of gefitinib resistance in non-small cell lung cancer (NSCLC), and demonstrate whether long noncoding RNA (lncRNA) expression signatures differ between gefitinib-sensitive PC9 and gefitinib-resistant PC9 (PC9-R) cell lines. PC9 and PC9-R cells were treated with gefitinib and, after 48 h, proliferation and apoptosis were analyzed using a Cell Counting Kit-8 (CCK-8) assay and flow cytometry. Microarray expression profiling of lncRNAs was undertaken in both PC9 and PC9-R cells, and the expression profiles were verified by reverse transcription quantitative-polymerase chain reaction. The EGFR/PI3K/AKT signaling pathway and mitochondrial apoptosis protein expression levels were assessed by western blot analysis. The PC9 cell line treated with gefitinib had a more significant effect on cell viability and apoptosis than the PC9-R cell line (P<0.05). Expression of various lncRNAs differed significantly between the two cell lines, and MIR31HG expression in particular was significantly higher in PC9-R cells. As expected, MIR31HG lncRNA knockdown sensitized PC9-R cells to gefitinib, and further experiments revealed that turning off the EGFR/PI3K/AKT signaling pathway activated expression of p53 in PC9-R cells transfected with si-MIR31HG. Furthermore, PC9-R cells transfected with si-MIR31HG induced cell apoptosis through the mitochondrial apoptosis pathway, and arrested the cell cycle in the G0/G1 phase. The results of the current study suggest that MIR31HG lncRNA levels in PC9-R cells are higher than in PC9 cells. Furthermore, overexpression of MIR31HG lncRNAs may contribute to gefitinib resistance in PC9-R cells through the EGFR/PI3K/AKT pathway, which impacts on cell proliferation, apoptosis and the cell cycle. MIR31HG lncRNA may therefore be a novel candidate biomarker for future therapeutic strategies involving EGFR-TKIs.