Mallotumides A-C: Potent Cytotoxic Cycloheptapeptides from the Roots of Mallotus spodocarpus.

The structures of potent cytotoxic cycloheptapeptides, mallotumides A-C (1-3, respectively) isolated from the roots of Mallotus spodocarpus Airy Shaw, were elucidated by extensive spectroscopic analysis. The absolute configuration of 1 was determined by single-crystal X-ray crystallographic data. All three cycloheptapeptides exhibited potent cytotoxicity against various cancer cell lines with IC50 values ranging from 0.60 to 4.02 nM.

Six-MicroRNA Prognostic Signature in Patients With Locally Advanced Head and Neck Squamous Cell Carcinoma.

PURPOSE: MicroRNAs (miRNAs) have been evaluated as biomarkers in cancers. Therefore, we aimed to identify a prognostic miRNA signature from The Cancer Genome Atlas (TCGA) database and validate it in the Ramathibodi (RA) locally advanced head and neck squamous cell carcinoma (LA-HNSCC) cohort. METHODS: The correlation between candidate miRNAs and the survival of patients with LA-HNSCC in TCGA database was analyzed. A prognostic miRNA signature model was generated that classified patients into high-risk and low-risk groups. This candidate miRNA signature was further validated in the independent RA cohort using droplet-digital polymerase chain reaction. RESULTS: In TCGA database, we compared the expression of 277 miRNAs between 519 head and neck squamous cell carcinoma tissues and 44 normal tissues. The expression of hsa-miR-10b, hsa-miR-148b, hsa-miR-99a, hsa-miR-127, hsa-miR-370, and hsa-miR-500a was independently associated with overall survival (OS). Thus, we established the miRNA signature risk score from these six miRNAs and categorized patients into low-risk and high-risk groups. The median OS of TCGA patients was significantly shorter in the low-risk group than in the high-risk group (P < .001). The six-miRNA signature was further validated in the RA cohort (N = 87). The median OS of the low-risk group was significantly shorter compared with the high-risk group (P = .03). In multivariate analysis, the six-miRNA signature was an independent prognostic factor for OS in the RA cohort (HR, 1.958; 95% CI, 1.006 to 3.812; P = .048). CONCLUSION: We identified a prognostic six-miRNA signature for patients with LA-HNSCC from TCGA cohort and validated it in our independent cohort. However, larger studies are warranted to confirm these results.

Extracellular Vesicles from EGFR T790M/L858R-mutant Non-small Cell Lung Cancer Promote Cancer Progression.

BACKGROUND/AIM: Tyrosine kinase inhibitors (TKIs) are the first-line therapy for non-small cell lung cancer (NSCLC) patients harboring activating epidermal growth factor receptor (EGFR) mutations. Unfortunately, most patients quickly develop an acquired resistance to EGFR-TKIs. However, the effects of NSCLC harboring EGFR-T790M mutation on aggressive NSCLC phenotypes is still unclear. This study aimed to investigate the extracellular vesicles (EVs) involvement in promoting the aggressiveness of NSCLC cells. MATERIALS AND METHODS: EVs were isolated from the culture media of TKI-sensitive (HCC827) and TKI-resistant (H1975) NSCLC cells using ultracentrifugation. Cell viability, proliferation, migration, and invasion were examined following incubation with indicated EVs. RESULTS: HCC827 and H1975 cells showed time-dependent uptake of PKH67 dye labeled EVs. Incubation of EVs derived from H1975 cells (EV-H1975) did not alter the TKI sensitivity of HCC827 cells. Interestingly, EV-H1975 significantly increased HCC827 cells proliferation, invasion, and migration. By a phospho-kinase array, EV-H1975 increased phosphorylation of several proteins related to cell proliferation, invasion, and migration, including FAK, AKT, and ERK1/2, in HCC827 cells. CONCLUSION: EGFR-T790M NSCLC cells promote TKI-sensitive NSCLC cell aggressiveness, at least partially, through mechanisms associated with EVs.

More than a Bubble: Extracellular Vesicle microRNAs in Head and Neck Squamous Cell Carcinoma.

MicroRNAs (miRNAs) are a class of small non-coding RNA molecules that play a pivotal regulatory role in a broad variety of biological processes. Dysregulation of miRNAs is associated with several human diseases, particularly cancer. Extracellular vesicles (EVs) are crucial components in intercellular communication. As part of the cargo of EVs, miRNAs are involved in EV-mediated cell-to-cell interactions, including promotion or suppression of tumor development. The knowledge on the molecular mechanisms and clinical importance of EV-miRNAs in head and neck squamous cell carcinoma (HNSCC) has rapidly grown over the past years. In the present review, the current understanding regarding the effect of EV-miRNAs on HNSCC tumorigenesis is summarized, which includes effects on tumor proliferation, angiogenesis, invasion and metastasis, the tumor microenvironment, immune modulation, and treatment resistance. EV-miRNA-based biomarkers in liquid biopsies such as blood and saliva may open up new possibilities for employing EV-miRNAs for screening and early diagnostics as well as disease monitoring. Future perspectives include the promise of EV-miRNAs as a novel therapeutic target.

Ex vivo expansion and functional activity preservation of adult hematopoietic stem cells by a diarylheptanoid from Curcuma comosa.

Hematopoietic stem cells (HSCs, CD34+ cells) have shown therapeutic efficacy for transplantation in various hematological disorders. However, a large quantity of HSCs is required for transplantation. Therefore, strategies to increase HSC numbers and preserve HSC functions through ex vivo culture are critically required. Here, we report that expansion medium supplemented with ASPP 049, a diarylheptanoid isolated from Curcuma comosa, and a cocktail of cytokines markedly increased numbers of adult CD34+ cells. Interestingly, phenotypically defined primitive HSCs (CD34+CD38-CD90+) were significantly increased under ASPP 049 treatment relative to control. ASPP 049 treatment also improved two functional properties of HSCs, as evidenced by an increased number of CD34+CD38- cells in secondary culture (self-renewal) and the growth of colony-forming units as assessed by colony formation assay (multilineage differentiation). Transplantation of cultured CD34+ cells into immunodeficient mice demonstrated the long-term reconstitution and differentiation ability of ASPP 049-expanded cells. RNA sequencing and KEGG analysis revealed that Hippo signaling was the most likely pathway involved in the effects of ASPP 049. These results suggest that ASPP 049 improved ex vivo expansion and functional preservation of expanded HSCs. Our findings provide a rationale for the use of ASPP 049 to grow HSCs prior to hematological disease treatment.

Plasma extracellular vesicle microRNA-491-5p as diagnostic and prognostic marker for head and neck squamous cell carcinoma.

Poor survival of patients with locally advanced head and neck squamous cell carcinoma (LA-HNSCC) is partly due to early diagnosis difficulties and the lack of reliable biomarkers for predicting treatment outcomes. In the discovery cohort, plasma-derived extracellular vesicles (EVs) from LA-HNSCC patients (n = 48) and healthy volunteers (n = 12) were used for profiling for microRNA (miRNA) expression by NanoString analysis. Ten EV-associated miRNAs were differentially expressed between LA-HNSCC patients and healthy volunteers. Subsequently, the results were validated in the individual discovery and additional cases (HNSCC, n = 73; control, n = 20) by quantitative RT-PCR. Among 10 EV-miRNAs, four (miR-27b-3p, miR-491-5p, miR-1910-5p, and miR-630) were significantly dysregulated in LA-HNSCC patients (n = 73) compared with healthy volunteers (n = 20). The miRNA prediction models were developed to discriminate HNSCC patients from healthy volunteers. The model using miR-491-5p was selected as a diagnostic biomarker for LA-HNSCC with a sensitivity and specificity of 46.6% and 100%, respectively (P < .001). The dynamic changes of miRNA model score (ΔmiRNAs) were determined using scores pre- and postdefinitive treatment to further investigate the prognostic value of miRNA prediction models. The univariate and multivariate analyses indicated that ΔmiR-491-5p was the most powerful and independent prognostic indicator for overall survival (hazard ratio [HR] 5.66, 95% confidence interval, 1.77-18.01; P = .003) and disease-free survival (HR 2.82, 95% CI, 1.13-7.05; P = .027) of HNSCC patients. In summary, the miR-491-5p prediction model could serve as a blood-based diagnostic marker for LA-HNSCC. Moreover, ΔmiR-491-5p could be a potential monitoring prognostic marker to reflect the survival of HNSCC patients.

Exosomal microRNAs as potential biomarkers for osimertinib resistance of non-small cell lung cancer patients.

BACKGROUND: Osimertinib is an epidermal growth factor receptor-tyrosine kinase inhibitor that specifically targets the T790M mutation in cancer.Unfortunately, most non-small cell lung cancer (NSCLC) patients develop osimertinib resistance. Currently, the molecular biomarkers for monitoring osimertinib resistance are not available. OBJECTIVE: This study aimed to examine the profile of exosomal miRNA in the plasma of osimertinib-resistant NSCLC patients. METHODS: Plasma exosomal miRNA profiles of 8 NSCLC patients were analyzed by next-generation sequencing at osimertinib-sensitive and osimertinib-resistance stage.The expression of dysregulated exosomal miRNAs was validated and confirmed in another cohort of 19 NSCLC patients by qPCR. The relationship between exosomal miRNA upregulation and clinical prognosis, survival analysis was evaluated by Kaplan-Meier curves. RESULTS: In osimertinib-resistant NSCLC patients, 10 exosomal miRNAs were significantly dysregulated compared to baseline. Upregulation of all 10 candidate exosomal miRNAs tended to correlate with increased latency to treatment failure and improved overall survival. Among them, 4 exosomal miRNAs, miR-323-3p, miR-1468-3p, miR-5189-5p and miR-6513-5p were essentially upregulated and show the potential to be markers for the discrimination of osimertinib-resistance from osimertinib-sensitive NSCLC patients with high accuracy (p< 0.0001). CONCLUSIONS: Our results highlight the potential role of these exosomal miRNAs as molecular biomarkers for the detection of osimertinib resistance.

Expression and roles of system L amino acid transporters in human embryonal carcinoma cells.

BACKGROUND: Testicular germ cell tumors (TGCTs) are the most common malignant cancer in young men. Although TGCTs are generally responsive to platinum-based chemotherapy particularly cisplatin, acquired resistance in patients with metastasis still occurs resulting in poor prognosis. Specifically, differentiation of embryonal carcinoma (EC) cells, the stem cells of TGCTs, can lead to the reduction of cisplatin responsiveness. Therefore, novel therapeutic strategies for TGCTs are needed. System L amino acid transporters have been reported to be up-regulated and to play an important role in tumorigenesis. However, expression and role of system L amino acid transporters in TGCTs remain elusive. MATERIALS AND METHODS: Expression of system L amino acid transporters was analyzed in TGCT samples from The Cancer Genome Atlas (TCGA). Expression of LAT1, LAT2, and 4F2hc was examined in human embryonal carcinoma cell line NTERA2. Roles of system L amino acid transporters on NTERA2 cell survival, cell proliferation, pluripotency, and cisplatin sensitivity were evaluated. RESULTS: Based upon TCGA datasets, we found that two isoforms of system L (LAT1 and LAT2) and their chaperone protein 4F2hc are highly expressed in EC samples compared with other groups. Treatment with the system L inhibitor BCH significantly suppressed leucine uptake into the pluripotent EC cell line NTERA2. The malignant phenotypes including cell viability, cell proliferation, and clonal ability were decreased following BCH treatment. Nonetheless, system L inhibition did not alter expression of stemness genes in NTERA2 cells. After NTERA2 differentiation, expressions of LAT1 and LAT2 were decreased. Finally, co-administration of BCH enhanced cisplatin sensitivity in both undifferentiated and differentiated cells. These effects were associated with the reduction in p70S6K phosphorylation. CONCLUSION: Taken together, these results shed light on the roles of system L amino acid transporters in TGCTs. Therefore, system L amino acid transporters could provide novel therapeutic targets for treatment against TGCTs.

Dysregulated microRNA expression profiles in cholangiocarcinoma cell-derived exosomes.

AIM: Cholangiocarcinoma (CCA) is a malignant tumor of bile duct epithelial cells. The prognosis of CCA is poor due to lack of effective therapeutic targets and detection at an advanced stage. Exosomes are secreted nano-sized vesicles and contribute to the malignancy of several cancers via transferring their miRNAs between cells. Thus, exosomal miRNAs may serve as new therapeutic targets and potential biomarkers for CCA. MAIN METHODS: Exosomes were isolated from three different CCA cell lines and normal human cholangiocyte cells, followed by miRNA profiling analysis. Potential role of dysregulated miRNA was investigated by knockdown experiment. KEY FINDINGS: We found that 38 and 460 miRNAs in CCA exosomes were significantly up- and down-regulated, respectively. Of these differentially expressed miRNAs, the hsa-miR-205-5p and miR-200 family members were markedly up-regulated for 600-1500 folds, whereas the miR-199 family members and their clustered miRNA, hsa-miR-214-3p, were down-regulated for 1000-2000 folds. The expression patterns of these representative exosomal miRNAs were similar to those observed in all types of CCA cells. The target genes of the top ten most up- and down-regulated miRNAs are significantly associated with well-characterized cancer-related pathways. Consistently, knockdown of the most up-regulated miRNA, miR-205-5p, reduced KKU-M213 cell invasion and migration. SIGNIFICANCE: We have demonstrated the distinct miRNA signatures in exosomes released from CCA cells, compared to normal human cholangiocyte cells. These exosomal miRNAs may have the potential to be novel therapeutic targets and biomarkers for CCA.

Interrogation of ethnomedicinal plants for synthetic lethality effects in combination with deficiency in the DNA repair endonuclease RAD1 using a yeast cell-based assay.

ETHNOPHARMACOLOGICAL RELEVANCE: Plant materials used in this study were selected based on the ethnobotanical literature. Plants have either been utilized by Thai practitioners as alternative treatments for cancer or identified to exhibit anti-cancer properties. AIM OF THE STUDY: To screen ethnomedicinal plants using a yeast cell-based assay for synthetic lethal interactions with cells deleted for RAD1, the yeast homologue of human ERCC4 (XPF) MATERIALS AND METHODS: Ethanolic extracts from thirty-two species of medicinal plants utilized in Thai traditional medicine were screened for synthetic lethal/sick interactions using a yeast cell-based assay. Cell growth was compared between the parental strain and rad1∆ yeast following exposure to select for specific toxicity of plant extracts. Candidate extracts were further examined for the mode of action using genetic and biochemical approaches. RESULTS: Screening a library of ethanolic extracts from medicinal plants identified Bacopa monnieri and Colubrina asiatica as having synthetic lethal effects in the rad1∆ cells but not the parental strain. Synthetic lethal effects for B. monneiri extracts were more apparent and this plant was examined further. Genetic analysis indicates that pro-oxidant activities and defective excision repair pathways do not significantly contribute to enhanced sensitivity to B. monneiri extracts. Exposure to B. monneiri extracts resulted in nuclear fragmentation and elevated levels of ethidium bromide staining in rad1∆ yeast suggesting promotion of an apoptosis-like event. Growth inhibition also observed in the human Caco-2 cell line suggesting the effects of B. monnieri extracts on both yeast and human cells may be similar. CONCLUSIONS: B. monneiri extracts may have utility in treatment of colorectal cancers that exhibit deficiency in ERCC4 (XPF).

Proteomics profiling of cholangiocarcinoma exosomes: A potential role of oncogenic protein transferring in cancer progression.

Cholangiocarcinoma (CCA), a common primary malignant tumor of bile duct epithelia, is highly prevalent in Asian countries and unresponsive to chemotherapeutic drugs. Thus, a newly recognized biological entity for early diagnosis and treatment is highly needed. Exosomes are small membrane bound vesicles found in body fluids and released by most cell types including cancer cells. The vesicles contain specific subset of proteins and nucleic acids corresponding to cell types and play essential roles in pathophysiological processes. The present study aimed to assess the protein profiles of CCA-derived exosomes and their potential roles. We have isolated exosomes from CCA cells namely KKU-M213 and KKU-100 derived from Thai patients and their roles were investigated by incubation with normal human cholangiocyte (H69) cells. Exosomes were internalized into H69 cells and had no effects on viability or proliferation of the host cells. Interestingly, the exosomes from KKU-M213 cells only induced migration and invasion of H69 cells. Proteomic analysis of the exosomes from KKU-M213 cells disclosed multiple cancer related proteins that are not present in H69 exosomes. Consistent with the protein profile, treatment with KKU-M213 exosomes induced ß-catenin and reduced E-cadherin expressions in H69 cells. Collectively, our results suggest that a direct cell-to-cell transfer of oncogenic proteins via exosomal pathway may be a novel mechanism for CCA progression and metastasis.