SLC38A5 promotes glutamine metabolism and inhibits cisplatin chemosensitivity in breast cancer.

BACKGROUND: Solute carrier family 38 member 5 (SLC38A5), as an amino acid transporter, play a vital role in cellular biological processes. In this study, we analyzed the function of SLC38A5 and its potential mechanism in breast cancer (BC) progression. METHODS: The expression of SLC38A5 in cancer and adjacent-normal tissues was analyzed by qRT-PCR and Western blot, and its correlation with patient prognosis was analyzed. The immunohistochemical staining of cancer tissues and adjacent-normal tissues was performed on SLC38A5-positive specimens. BC mice were successfully applied to examine the role of SLC38A5 on tumor proliferation using the CCK-8 assay. In BC cells and mouse tumor tissues, SLC38A5 and PCNA expression were determined by Western blotting. RESULTS: The study found that SLC38A5 was highly expressed in BC patients and associated with a poor survival. SLC38A5 silencing inhibited BC cell viability and glutamine uptake. In addition, SLC38A5 overexpression promoted BC cell viability via the glutamine metabolism. SLC38A5 inhibited cisplatin chemosensitivity in BC cells. Importantly, SLC38A5 silencing inhibited tumor growth in vivo. CONCLUSION: Our findings suggest that SLC38A5 enhances BC cell viability by glutamine metabolism, inhibits the chemical sensitivity of cisplatin in BC cells, and promotes tumor growth, emphasizing the clinical relevance of SLC38A5 in BC management as a novel potential therapeutic target.

Nutlin-3 suppresses tumorigenesis and progression of oral squamous cell carcinoma and enhances chemosensitivity to cisplatin.

Oral squamous cell carcinoma (OSCC) is an epithelial malignant tumor with great challenges of tumor metastasis and drug resistance. Nutlin-3 is a MDM2 inhibitor that can potently activate tumor suppressor gene p53. However, the exact role of Nutlin-3 in OSCC has not been identified yet. SCC-9 cells were treated with 0, 2.5, 5, 10, 20 µM Nutlin3. MDM2 and p53 protein levels were assessed using western blot analysis. Then, CCK8 assay, clone formation assay, TUNEL staining, wound healing and transwell assays were conducted to analyze the influences of Nutlin3 on the proliferation, apoptosis, migration, and invasion in SCC-9 cells. Moreover, SCC-9 cells were co-treated with 0, 0.5, 1, 2.5, 5 µM cisplatin and Nutlin3 to determine the effect of Nutlin3 on cisplatin chemosensitivity in OSCC. As expected, Nutlin-3 inhibited MDM2 but restored p53 in OSCC in a concentration-dependent manner. Meanwhile, Nutlin-3 suppressed the proliferation, clone formation, migration, invasion and epithelial-mesenchymal transition of SCC-9 cells and both boosted the apoptosis. In addition, Nutlin-3 caused a reduced cell viability and an elevated cell apoptosis rate in cisplatin-treated SCC-9 cells, indicating that Nutlin-3 enhanced cisplatin chemosensitivity in OSCC cells. Taken together, Nutlin-3 may suppress tumorigenesis and progression of OSCC and enhance chemosensitivity to cisplatin in OSCC.

USP39 attenuates the antitumor activity of cisplatin on colon cancer cells dependent on p53.

Cisplatin is the effective chemotherapeutic drug in colon cancer treatment, but its therapeutic efficacy is limited by intrinsic or acquired drug resistance and detrimental side effects. Therefore, improving the effect of cisplatin chemotherapy remains a great challenge. The previous study identified that USP39 was relevant to cisplatin resistance of lung cancer. However, the function and mechanisms of USP39 regulating the chemosensitivity of cisplatin in colorectal cancer remain unclear. In this study, we reveal that USP39 is associated with colon cancer cells sensitivity to cisplatin. Depletion of USP39 enhances the cisplatin-induced apoptosis in HCT116 cells. Conversely, overexpression of USP39 attenuates apoptosis in RKO cells. Furthermore, we demonstrate that USP39 depletion promotes apoptosis induced by cisplatin, which is related with the induction of oxidative stress and DNA damage response. Further studies show that USP39 regulates cisplatin-induced apoptosis dependent on p53. The underlying mechanism is demonstrated by knocking down USP39, that results in p53 upregulation, associated with its prolonged half-life. Collectively, our findings reveal that USP39 might be a negative factor of the p53 mediated cisplatin sensitivity of colon cancer, and suggest USP39 as a potential molecular target for cisplatin chemotherapy of colon cancer.

LncRNA MEG3 promotes cisplatin sensitivity of cervical cancer cells by regulating the miR-21/PTEN axis.

BACKGROUND: Cervical cancer (CC) is a common gynecological malignancy worldwide. Some patients perform serious resistance after chemotherapy, and long-stranded non-coding RNA MEG3 is reported to be involved in the regulation of chemoresistance in many solid tumors. However, its involvement in cervical adenocarcinoma has not been reported. METHODS: Hela cell lines, cisplatin-resistant cell lines (Hela-CR) and nude mice were used in this study. After MEG3 was overexpressed or knocked down in cells by the lentivirus vector, cell growth was detected by the CCK-8 assay, and cell migration was evaluated using Transwell assay. Quantitative real-time polymerase chain reaction (qRT-PCR) was performed to examine the expression of MEG3, miR-21 and PTEN mRNA. Apoptosis was detected by flow cytometry. The targeting relationship between mRNAs was predicted and verified using dual-luciferase reporter gene experiments. Western blot was executed to examine Bax, cleaved-caspase 3, Bcl-2, PTEN and GAPDH expression. Cells were injected into the mice to form xenograft tumors to compare tumorigenesis capacity. RESULTS: We demonstrated that MEG3 was down-regulated in cervical cancer by analyzing the TCGA database. Moreover, knockdown of MEG3 promoted CC cell proliferation, migration and inhibited the apoptosis. These changes of CC cells were more pronounced under cisplatin treatment. Further studies showed that the MEG3/miR-21/PTEN axis affected cisplatin sensitivity in cervical cancer cells, and these results of recue assay were used to confirm this conclusion. CONCLUSIONS: MEG3 performing as ceRNA promotes cisplatin sensitivity in CC cells through the miR-21/PTEN axis.

YTHDF2 interference suppresses the EMT of cervical cancer cells and enhances cisplatin chemosensitivity by regulating AXIN1.

M6A reader YTH structural domain family 2 (YTHDF2) has been recognized to play an oncogenic role in numerous tumors, but its role in cervical cancer has not been extensively discussed yet. This paper was designed to explore the role of YTHDF2 in cervical cancer and identify its underlying mechanism. The expression of YTHDF2 was first determined in cervical cancer cells by quantitative reverse-transcription polymerase chain reaction and western blot. Then, the migration, invasion, and epithelial-mesenchymal transition (EMT) process were observed in YTHDF2-knockdown Hela cells using wound healing, transwell and immunofluorescence assays. The cisplatin chemosensitivity of Hela cells was also investigated by assessing cell activity with cell counting kit-8 and TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling). After MeRIP-Seq assay and actinomycin D treatment to confirm the binding relationship between YTHDF2 and AXIN1, the migration, invasion, EMT process, and cisplatin chemosensitivity were assessed again in Hela cells silenced by YTHDF2 and AXIN1 or treated with Wnt agonist. YTHDF2 was increased in cervical cancer cells, and depletion of YTHDF2 led to reduced migration, invasion and EMT process but enhanced chemosensitivity of cisplatin in Hela cells. Furthermore, YTHDF2 could bind to and stabilize the expression of AXIN1. When the YTHDF2-knockdown Hela cells were further transfected with AXIN1 knockdown or treated with Wnt agonist, the effects of YTHDF2 knockdown on the migration, invasion and EMT process were partially abolished, together with reduced cisplatin chemosensitivity. To sum up, we reported that YTHDF2 interference could suppress the EMT of cervical cancer cells and enhance cisplatin chemosensitivity by regulating AXIN1.

Falcarindiol Enhances Cisplatin Chemosensitivity of Hepatocellular Carcinoma via Down-Regulating the STAT3-Modulated PTTG1 Pathway.

Hepatocellular carcinoma (HCC) is the most frequent primary liver malignancy globally and the third leading cause of cancer-related death. Chemotherapy is one of the main methods in treating HCC, while recent studies have found that the resistance of HCC to chemotherapeutic drugs reduces the efficacy of the chemotherapy. Falcarindiol (FAD) is a cytotoxic and anti-inflammatory polyacetylenic oxylipin found in food plants of the carrot family (Apiaceae), while its role in HCC remains to be explored. Here, HCC cells (Huh7 and LM3) were treated with FAD at different doses. Cell proliferation was tested by the cell counting kit-8 (CCK-8) method and colony formation assay, while the apoptosis was monitored by flow cytometry. The profiles of apoptosis-related proteins (Bax, bcl2, and Caspase-3), DNA repair proteins (Rad51, BRCA1, and MDC1), and the signal transducer and activator of transcription 3 (STAT3)/Pituitary Tumor Transforming Gene 1 (PTTG1) were verified by western blot (WB) or quantitative reverse transcription-polymerase chain reaction (qRT-PCR). The interaction between STAT3 and PTTG1 was verified by immunoprecipitation (IP). In addition, a xenograft tumor model was constructed in mice to explore the anti-tumor effects of FAD in vivo, and immunohistochemistry (IHC) was performed to count the number of Ki67-stained cells. As a result, FAD inhibited HCC cell proliferation and DNA repair, facilitated their apoptosis, and also enhanced cisplatin (DDP) chemosensitivity. The Combination Index (CI) evaluation showed that FAD and DDP had synergistic effects in repressing HCC cell proliferation. Besides, FAD dampened the STAT3/PTTG1 pathway expression. Further studies revealed that inhibiting STAT3 enhanced the inhibitive effect of FAD on HCC cells, whereas overexpressing PTTG1 attenuated the anti-tumor effect of FAD. Overall, our study illustrated that FAD is a potential anticancer drug and strengthens the chemosensitivity of HCC cells to DDP by inhibiting the STAT3/PTTG1 pathway.

MiR-149-5p regulates cisplatin chemosensitivity, cell growth, and metastasis of oral squamous cell carcinoma cells by targeting TGFß2.

BACKGROUND: Oral squamous cell carcinoma (OSCC) is a public health problem worldwide. MicroRNAs, acting as either oncogenes or tumor suppressors, have gathered much attention. The aim of this study was to characterize the role of miR-149-5p in drug resistance, cell growth, and metastasis and its underlying mechanism in oral squamous cell carcinoma. METHODS: The expressions of miR-149-5p and TGFß2 were measured by quantitative real-time polymerase chain reaction. The survival rate of cells treated with different concentrations of CDDP was checked by CCK-8. The cell proliferation and apoptosis was determined by CCK-8 and flow cytometry, respectively. Cell migration and invasion were examined using transwell assay. The interaction of miR-149-5p and TGFß2 was predicted by online software Targetscan and confirmed by luciferase reporter assay. The protein expression of TGFß2, p-SMAD2 and p-SMAD3 was quantified using western blot. RESULTS: The expression of miR-149-5p was obviously decreased in OSCC tissues and cell lines, and its expression was lower in a cisplatin resistant cell line (CAL-27/CDDP) than that of a normal OSCC cell line (CAL-27). CCK-8 assay suggested that miR-149-5p increased drug sensitivity in CAL-27 and CAL-27/CDDP cells. miR-149-5p attenuated proliferation, migration and invasion, and promoted apoptosis of CAL-27 and CAL-27/CDDP cells. In addition, TGFß2 was up-regulated in OSCC cells at both mRNA and protein levels. Moreover, miR-149-5p promoted cisplatin chemosensitivity and regulated cell proliferation, apoptosis, migration and invasion by targeting TGFß2 in CAL-27 and CAL-27/CDDP cells. CONCLUSION: miR-149-5p regulates cisplatin chemosensitivity, cell growth, apoptosis and metastasis by targeting TGFß2. miR-149-5p/TGFß2 axis has potential for therapy of OSCC.

DEPTOR improves cisplatin chemosensitivity in esophageal squamous cell carcinoma cells by inducing Caspase-1-mediated pyroptosis / 药学学报

Chemotherapy resistance is the main cause of poor prognosis in patients with advanced esophageal squamous cell carcinoma (ESCC). Pyroptosis is one of the anti-tumor mechanisms by chemotherapy drugs. Studies have shown that DEP-domain containing mTOR-interacting protein (DEPTOR) is correlated with sorafenib and gefitnib resistance, which is discovered as a naturally negative regulator of mammalian/mechanistic target of rapamicin (mTOR). In this study, DEPTOR knockdown (shDEPTOR) lentivirus was used to establish the stable DEPTOR knockdown ESCC cell lines. The results showed that knockdown of DEPTOR reduced chemosensitivity to cisplatin in ESCC cells in vitro. The lower expression of DEPTOR caused less extensive morphological characteristics of pyroptosis than that was observed in sh-con cells with the treatment of cisplain. Further studies showed that knockdown of DEPTOR induced downregulation of Caspase-1 expression and reduction of Caspase-1 activation, thereby inhibiting the activation of the classical pathway of pyroptosis. This paper demonstrates that DEPTOR can improve cisplatin chemosensitivity in ESCC cells via inducing Caspase-1-mediated pyroptosis.

Long noncoding RNA SFTA1P promoted apoptosis and increased cisplatin chemosensitivity via regulating the hnRNP-U-GADD45A axis in lung squamous cell carcinoma.

Chemotherapeutic insensitivity remains one of the major obstacles in clinical treatment of lung squamous cell carcinoma (LSCC). Recently, increasing evidence has suggested that long non-coding RNAs (lncRNAs) promote tumorigenesis in many cancer types. However, the potential biological roles and regulatory mechanisms of lncRNAs in response to cisplatin treatment are poorly understood. Here, we found that lncRNA SFTA1P (surfactant associated 1, pseudogene), highly expressed in lung, was down-regulated in LSCC tissues and could be induced upon cisplatin treatment in LSCC cells. Elevated SFTA1P induced apoptosis and enhanced the sensitivity to cisplatin of LSCC cells. We further identified that hnRNP-U (heterogeneous nuclear ribonucleoprotein U) was down-regulated in LSCCs and positively correlated with patients' poor prognosis as well as SFTA1P. Mechanistic studies revealed that SFTA1P could up-regulate hnRNP-U expression. In addition, we identified that hnRNP-U enhanced cisplatin-induced apoptosis through up-regulation of GADD45A, high expression of which was correlated with good prognosis in LSCC patients. Our findings demonstrated that SFTA1P might serve as a useful biomarker for LSCC diagnosis and a predictor for cisplatin chemotherapy response in patients with LSCC.