Paclitaxel Chemosensitivity Research Articles

Tumor-associated macrophages/C-X-C motif chemokine ligand 1 promotes breast cancer autophagy-mediated chemoresistance via IGF1R/STAT3/HMGB1 signaling

Autophagy-mediated chemoresistance is the core mechanism for therapeutic failure and poor prognosis in breast cancer. Breast cancer chemotherapy resistance is believed to be influenced by tumor-associated macrophages (TAMs), by which C-X-C motif chemokine ligand 1 (CXCL1) is the most abundant cytokine secreted. Yet, its role in mediating autophagy-related chemoresistance is still unknown. This study aimed to explore the molecular mechanisms by which TAMs/CXCL1 induced autophagy-mediated chemoresistance in breast cancer. It was found that TAMs/CXCL1 promoted chemoresistance of breast cancer cells through autophagy activation in vitro, and CXCL1 silence could enhance the chemosensitivity of paclitaxel-resistant breast cancer cells via autophagy inhibition. A high-throughput quantitative PCR chip and subsequent target validation showed that CXCL1 induced autophagy-mediated chemoresistance by inhibiting VHL-mediated IGF1R ubiquitination. The elevated IGF1R then promoted STAT3/HMGB1 signaling to facilitate autophagy. Additionally, TAMs/CXCL1 silence improved paclitaxel chemosensitivity by suppressing autophagy in breast cancer mice xenografts, and clinical studies further linked CXCL1 to IGF1R/HMGB1 signaling, as well as shorter free survival of recurrence. Taken together, these results not only uncover the crucial role of TAMs/CXCL1 signaling in mediating breast cancer chemoresistance through enhancing autophagy, but also shed novel light on the molecular mechanism of IGF1R/STAT3/HMGB1 pathway in regulating autophagy and its impact on cancer prognosis.

The deubiquitinase OTUD5 stabilizes SLC7A11 to promote progression and reduce paclitaxel sensitivity in triple-negative breast cancer

Ferroptosis is a newly defined form of programmed cell death characterized by iron-dependent lipid peroxide accumulation and is associated with the progression of cancer. Solute carrier family 7 member 11 (SLC7A11), a key component of cystine/glutamate antiporter, has been characterized as a critical regulator of ferroptosis. Although many studies have established the transcriptional regulation of SLC7A11, it remains largely unknown how the stability of SLC7A11 is regulated in cancers, especially in triple-negative breast cancer (TNBC). Here we demonstrated that ovarian tumor domain-containing protein 5 (OTUD5), which deubiquitinated and stabilized SLC7A11, played a key role in TNBC progression and paclitaxel chemosensitivity through modulating ferroptosis. The clinical data analysis showed OTUD5 was higher expressed in TNBC, which positively correlated with SLC7A11 level. Mechanistically, OTUD5 interacted with SLC7A11 and cleaved K48-linked polyubiquitin chains from SLC7A11 to enhance the stability of SLC7A11. Taken together, these findings uncover a functional and mechanistic role of OTUD5 in TNBC progression and paclitaxel sensitivity, indicating OTUD5 could be a potential target for TNBC treatment.

Chemotherapy-elicited extracellular vesicle CXCL1 from dying cells promotes triple-negative breast cancer metastasis by activating TAM/PD-L1 signaling

BackgroundTriple-negative breast cancer (TNBC) is the most aggressive subtype of breast cancer, and chemotherapy still serves as the cornerstone treatment functioning by inducing cytotoxic cell death. Notably, emerging evidence suggests that dying cell-released signals may induce cancer progression and metastasis by modulating the surrounding microenvironment. However, the underlying molecular mechanisms and targeting strategies are yet to be explored.MethodsApoptotic TNBC cells induced by paclitaxel or adriamycin treatment were sorted and their released extracellular vesicles (EV-dead) were isolated from the cell supernatants. Chemokine array analysis was conducted to identify the crucial molecules in EV-dead. Zebrafish and mouse xenograft models were used to investigate the effect of EV-dead on TNBC progression in vivo.ResultsIt was demonstrated that EV-dead were phagocytized by macrophages and induced TNBC metastasis by promoting the infiltration of immunosuppressive PD-L1+ TAMs. Chemokine array identified CXCL1 as a crucial component in EV-dead to activate TAM/PD-L1 signaling. CXCL1 knockdown in EV-dead or macrophage depletion significantly inhibited EV-dead-induced TNBC growth and metastasis. Mechanistic investigations revealed that CXCL1EV-dead enhanced TAM/PD-L1 signaling by transcriptionally activating EED-mediated PD-L1 promoter activity. More importantly, TPCA-1 (2-[(aminocarbonyl) amino]-5-(4-fluorophenyl)-3-thiophenecarboxamide) was screened as a promising inhibitor targeting CXCL1 signals in EVs to enhance paclitaxel chemosensitivity and limit TNBC metastasis without noticeable toxicities.ConclusionsOur results highlight CXCL1EV-dead as a novel dying cell-released signal and provide TPCA-1 as a targeting candidate to improve TNBC prognosis.Graphical abstract

An integrative pan-cancer analysis of WWC family genes and functional validation in lung cancer

The WW and C2 domain containing (WWC) protein family functions as scaffolds regulating cell proliferation and organ growth control through the Hippo signaling pathway. However, their pan-cancer dysregulation and mechanistic roles in signaling transduction have remained unclear. We performed integrated pan-cancer analyses of WWC family gene expression using data from The Cancer Genome Atlas (TCGA) across 33 different cancer types. Prognostic relevance was evaluated by survival analyses. WWC genetic alterations, DNA methylation, pathway activities, drug response, and tumor immunology were analyzed using online databases. Furthermore, we examined the functional roles of WWCs in lung cancer cells. We observed aberrant WWC expression in various cancers, which associated with patient prognosis. WWC hypermethylation occurred in many cancers and exhibited negative correlation with expression, alongside mutations linked to poor outcomes. Pathway analysis implicated WWCs as Hippo pathway scaffolds, while drug sensitivity analysis suggested associations with diverse chemotherapies. Additionally, pan-cancer analyses elucidated vital immunomodulatory roles for WWC through heterogeneous correlations with immune cell infiltrates, checkpoint molecules, tumor mutation burden, microsatellite instability, and chemokine pathways across cancers. Experimentally, WWCs suppressed lung cancer cell proliferation, migration, and invasion while enhancing apoptosis and paclitaxel chemosensitivity. Mechanistically, WWCs bound large tumor suppressor 1 and 2 (LATS1/2) kinases to stimulate phosphorylation cascades, thereby inhibiting nuclear translocation of the Yes-associated protein (YAP) oncoprotein. Taken together, our multi-omics characterization provides comprehensive evidence for WWCs as putative tumor suppressors across cancers via Hippo pathway modulation. WWCs may serve as prognostic markers and therapeutic targets in lung cancer.

MiR-203a-A multifaceted regulator modulating cancer hallmarks and therapy response.

MicroRNAs (miRNAs) are a class of noncoding RNAs of about 19-25 nucleotides, which serve as critical modulators of various cellular and biological processes by target gene regulation. Dysregulated expression of miRNAs modulates the pathophysiology of various human diseases, including cancer. Among miRNAs, miR-203a is one of the most extensively researched dysregulated miRNAs in different cancers. Our review investigated the roles of miR-203a in the hallmarks of cancer modulating different pathways through target gene regulations, chemoresistance, its crosstalk with other ncRNAs or genes in terms of ceRNAs impacting oncogenesis, and its potential applications in the diagnosis, prognosis, and chemotherapeutic responses in different cancer types. miR-203a impacts cancer cell behavior by regulating these exclusive hallmarks- sustaining proliferation, cell growth, invasion and metastasis, cell death, and angiogenesis. Besides, miR-203a is found in human circulating biofluids like plasma or serum of colorectal cancer, cervical cancer, and hepatocellular carcinoma, hinting at its potential as a biomarker. Further, miR-203a is involved in enhancing the chemosensitivity of cisplatin, docetaxel, paclitaxel, doxorubicin, and 5-fluorouracil in a variety of malignancies through their cognate target genes. These results suggest that miR-203a is a crucial multifaceted miRNA that controls cancer cell proliferation, metastasis, and chemotherapy response, shedding new light on its possible application.

The effect of propofol on chemosensitivity of paclitaxel in cervical cancer cells.

Propofol is a drug with potential anticancer effect. This study aimed to explore the effect of propofol on chemosensitivity of cervical cancer cells to paclitaxel. HeLa and CaSki cells were selected for drug experiments. Cell viability was evaluated via CCK-8 assay, and the combination index (CI) was calculated by CompuSyn software. A clinically relevant concentration and IC30 of propofol were selected in combination with 5 nM paclitaxel. BrdU incorporation, transwell, and flow cytometry assays were utilized to evaluate cell proliferation, migration, invasion, and apoptosis. The expression of β-tubulin, stathmin 1, and GAPDH proteins was evaluated by Western blot. The stathmin 1 cDNA plasmid was used to establish stathmin 1-overexpressing CaSki cells. At clinically relevant concentrations (0-80 μM), propofol did not affect cancer cell viability, but high concentrations (100-800 μM) reduced cell viability. The CI values of propofol with IC30 (200 μM in HeLa; 400 μM in CaSki) combined with 5 nM paclitaxel were <1. The effect of propofol with IC30 combined with paclitaxel on cell proliferation, migration, invasion, and apoptosis were stronger than individual effect, while 30 μM propofol had no effect. The Western blot results showed 30 μM propofol did not affect β-tubulin and stathmin 1 expression in cells, although paclitaxel upregulated β-tubulin expression while downregulating stathmin 1 expression. Compared with paclitaxel alone, cotreatment with propofol at its IC30 and paclitaxel decreased stathmin 1 expression but had no effect on β-tubulin expression. High stathmin 1 expression weakened the effect of paclitaxel on cell viability and apoptosis, while propofol partially reversed these effect. Propofol at clinically relevant concentrations had no effect on the malignant biological behaviors of cervical cancer cells, while propofol at high concentrations decreased.Propofol with IC30 and paclitaxel had synergetic effect on cancer cells through a reduction in stathmin 1 expression.

MiR-145 inhibits cell migration and increases paclitaxel chemosensitivity in prostate cancer cells.

Prostate cancer (PC) is one of the most commonly diagnosed malignancies among men worldwide. Paclitaxel is a chemotherapeutic agent widely used to treat different types of cancer. Recent studies revealed miRNAs control various genes that influence the regulation of many biological and pathological processes such as the formation and development of cancer, chemotherapy resistance, etc. Between three PC cell lines (PC3, DU-145, LNCAP), PC3 showed the lowest miR-145 expression and was chosen for experiments. PC3 cells were treated with paclitaxel and miR-145 separately or in combination. To measure the cell viability, migratory capacity, autophagy, cell cycle progression, and apoptosis induction, the MTT assay, wound-healing assay, and Annexin V/PI apoptosis assay were used, respectively. Moreover, quantitative real-time PCR (qRT-PCR) was employed to measure the expression level of genes involved in apoptosis, migration, and stemness properties. Obtained results illustrated that miR-145 transfection could enhance the sensitivity of PC3 cells to paclitaxel and increase paclitaxel-induced apoptosis by modulating the expression of related genes, including Caspase-3, Caspase-9, Bax, and Bcl-2. Also, results showed combination therapy increased cell cycle arrest at the sub-G1 phase. miR-145 and paclitaxel cooperatively reduced migration ability and related-metastatic and stemness gene expression, including MMP-2, MMP-9, CD44, and SOX-2. In addition, combination therapy can suppress MDR1 expression. These results confirmed that miR-145 combined with paclitaxel cooperatively could inhibit cell proliferation and migration and increase the chemosensitivity of PC3 cells compared to mono treatment. So, miR-145 combination therapy may be used as a promising approach for PC treatment.

MARK2 regulates chemotherapeutic responses through class IIa HDAC-YAP axis in pancreatic cancer.

Despite paclitaxel's wide use in cancer treatment, patient response rate is still low and drug resistance is a major clinical obstacle. Through a Phos-tag-based kinome-wide screen, we identified MARK2 as a critical regulator for paclitaxel chemosensitivity in PDAC. We show that MARK2 is phosphorylated by CDK1 in response to antitubulin chemotherapeutics and in unperturbed mitosis. Phosphorylation is essential for MARK2 in regulating mitotic progression and paclitaxel cytotoxicity in PDAC cells. Mechanistically, our findings also suggest that MARK2 controls paclitaxel chemosensitivity by regulating class IIa HDACs. MARK2 directly phosphorylates HDAC4 specifically during antitubulin treatment. Phosphorylated HDAC4 promotes YAP activation and controls expression of YAP target genes induced by paclitaxel. Importantly, combination of HDAC inhibition and paclitaxel overcomes chemoresistance in organoid culture and preclinical PDAC animal models. The expression levels of MARK2, HDACs, and YAP are upregulated and positively correlated in PDAC patients. Inhibition of MARK2 or class IIa HDACs potentiates paclitaxel cytotoxicity by inducing mitotic abnormalities in PDAC cells. Together, our findings identify the MARK2-HDAC axis as a druggable target for overcoming chemoresistance in PDAC.

Elevated AKIP1 expression is associated with tumor invasion, shorter survival time and decreased chemosensitivity in endometrial carcinoma.

A-kinase-interacting protein 1 (AKIP1), as a recently discovered oncoprotein, promotes cell malignant behaviors in gynecological malignancies. To the best of our knowledge, no study reports its clinical value in patients with endometrial carcinoma. The present study aimed to explore the association between AKIP1 expression and clinical features and survival in patients with endometrial carcinoma, and to assess the effect of AKIP1 knockdown on the regulation of chemosensitivity in vitro. The tumor and adjacent tissue specimens from 101 patients with endometrial carcinoma were retrieved for AKIP1 protein expression analysis using an immunohistochemistry (IHC) assay. Meanwhile, specimens from 54 patients with endometrial carcinoma were analyzed for AKIP1 mRNA expression using reverse transcription-quantitative PCR. Furthermore, an in vitro experiment was conducted in the Ishikawa cell line to determine the effect of AKIP1 modification on the chemosensitivity of cisplatin and paclitaxel. AKIP1 IHC score (P<0.001) and mRNA expression levels (P<0.001) were increased in tumor tissues compared with those in adjacent tissues. Moreover, increased AKIP1 IHC score was associated with lymphovascular invasion (P=0.007), advanced International Federation of Gynecology and Obstetrics (FIGO) stage (P=0.002) and shorter overall survival (OS) time (P=0.035) in the patients with endometrial carcinoma. Meanwhile, upregulated AKIP1 mRNA expression levels were associated with lymphovascular invasion (P=0.020) and advanced FIGO stage (P=0.027) in the patients with endometrial carcinoma. Multivariate Cox regression showed that tumor AKIP1 protein expression (high vs. low) independently predicted a shorter OS time (P=0.036). Silencing of AKIP1 decreased Ishikawa cell viability when treated with 5, 10, 20 and 40 µM cisplatin (all P<0.05) and decreased the half maximal inhibitory concentration value of cisplatin (P=0.003), whereas its effect on paclitaxel chemosensitivity was less obvious. Overall, elevated AKIP1 expression was associated with tumor invasion, shorter survival time and decreased chemosensitivity in endometrial carcinoma.

Apatinib inhibits tumour progression and promotes antitumour efficacy of cytotoxic drugs in oesophageal squamous cell carcinoma.

Apatinib, a highly selective inhibitor of vascular endothelial growth factor receptor‐2 (VEGFR‐2), inhibits the angiogenesis of tumours. The function and mechanism of apatinib in oesophageal squamous cell carcinoma (ESCC) remain unknown. In present study, we found that the development of ESCC in patients was controlled by treatment of combination of apatinib and a chemotherapeutic drug. Moreover, apatinib efficiently promotes cell apoptosis, inhibits cell proliferation, invasion, epithelial‐mesenchymal transition (EMT) and activity of the Akt/mTOR pathway in ESCC cells. Western blot analysis showed that apatinib significantly increased vimentin protein levels, decreased Bcl2, matrix metalloproteinase 9 (MMP9), E‐cadherin, p‐Akt and p‐mTOR protein levels in ESCC cells. Furthermore, apatinib enhanced chemosensitivity of cytotoxic drugs paclitaxel (TAX), 5‐fluorouracil (5‐FU) and cisplatin (DDP) by upregulating expression of vimentin protein, and downregulating expression of Bcl2, MMP9 and E‐cadherin protein in vitro. Compared with single‐agent groups, the combination of apatinib with each chemotherapeutic drug significantly repressed tumour growth and angiogenesis through blocking the expression of Ki67 and VEGFR‐2 in vivo. Taken together, apatinib efficiently inhibits cell growth through blocking Bcl2 and Akt/mTOR pathway, and suppresses metastasis via inhibiting MMP9 and EMT in ESCC cells. Apatinib promoted antitumour effect of chemotherapeutic agents through promoting cell apoptosis and inhibiting EMT and angiogenesis in ESCC.

Protein kinase RNA-activated controls mitotic progression and determines paclitaxel chemosensitivity through B-cell lymphoma 2 in ovarian cancer.

Anti-tubulin agents, such as paclitaxel, have been used extensively for treatment of several types of cancer, including ovarian, lung, breast, and pancreatic cancers. Despite their wide use in cancer treatment, however, patient response is highly variable and drug resistance remains a major clinical issue. Protein kinase RNA-activated (PKR) plays a critical role in immune response to viral infection. We identified PKR as a phospho-protein in response to anti-tubulin agents and this phosphorylation occurs independent of its own kinase activity. PKR is phosphorylated by cyclin-dependent kinase 1 (CDK1) during anti-tubulin treatment and unperturbed mitosis and that PKR regulates mitotic progression in a phosphorylation-dependent manner. Furthermore, inactivation of PKR confers resistance to paclitaxel in ovarian and breast cancer cells in vitro and in vivo. PKR expression levels and activity are decreased in chemotherapeutic recurrent ovarian cancer patients. Mechanistically, our findings suggest that PKR controls paclitaxel chemosensitivity through repressing Bcl2 expression. Pharmacological inhibition of Bcl2 with FDA-approved agent venetoclax overcomes paclitaxel resistance in preclinical animal models of ovarian cancer. Our results suggest that PKR is a critical determinant of paclitaxel cytotoxicity and that PKR-Bcl2 axis as a potential therapeutic target for the treatment of recurrent drug-resistant ovarian tumors.

RETRACTED: miR-98-5p inhibits gastric cancer cell stemness and chemoresistance by targeting branched-chain aminotransferases 1

AimsGastric cancer stem cells (GCSCs) have been used as a therapeutic target. This study aims to estimate the role of miR-98-5p (termed miR-98) in the development of GCSCs. Main methodsThe expression of miR-98 in CD44+ GCSCs was verified by RT-PCR. The miR-98 was overexpressed in CD44+ GCSCs by Lentivirus. The ability of self-renewal, invasion, chemoresistance and tumorigenicity was detected in vitro or in vivo after overexpression of miR-98. The target genes of miR-98 were predicted and verified by luciferase reporter assays. The effects miR-98/BCAT1 signaling on the chemoresistance and tumorigenicity of CD44+ GCSCs were investigated in a xenograft model by rescue experiments. Key findingsWe have shown that miR-98 was decreased in CD44+ GCSCs. The overexpression of miR-98 could inhibit the expression of stem-related genes and the ability of self-renewal, invasion, and tumorigenicity of GCSCs. Also, we found that miR-98 overexpression enhances the sensitivity to cisplatin treatment in vitro. Using a xenograft model, we showed that miR-98 overexpression reversed paclitaxel resistance to CD44+ GCSCs. Finally, we found that branched-chain aminotransferases 1 (BCAT1) is a target gene of miR-98. Overexpressed BCAT1 reversed xenograft tumor formation ability and attenuated the paclitaxel chemosensitivity induced by miR-98 downregulation. Furthermore, BCAT1 restoration affected the expression of invasion and drug resistance-related genes. SignificanceThis study revealed miR-98 inhibits gastric cancer cell stemness and chemoresistance by targeting BCAT1, suggesting that this miR-98/BCAT1 axis represents a potential therapeutic target in gastric cancer.

Abstract 3691A: Targeting MARK2-HDAC-YAP signaling to overcome paclitaxel resistance in PDAC

Abstract Nanoparticle albumin-bound (Nab)-paclitaxel (taxol) combined with gemcitabine has been approved as a first-line chemotherapy for advanced pancreatic ductal adenocarcinoma (PDAC) patients. However, the response rate is still very low due to the occurrence of drug resistance and attempts in reversing the resistance have not been successful in the clinic. MARK (microtubule affinity-regulating kinase) proteins (MARK1-4) are critical for microtubule dynamics by modulating MAPs (microtubule-associated proteins). They are members of the AMPK/Snf1 family and control cell polarity and asymmetric cell division. Dysregulation of MARKs has also been associated with pathological conditions such as cancer and Alzheimer disease. Several recent studies showed that MARK family members are important regulators of Hippo-YAP (Yes-associated protein) signaling, which is critical in cancer development, drug resistance, and stem cell biology. Through Phos-tag-based kinome-wide screens, we identified MARK2 as a critical determinant for mitotic progression and paclitaxel chemosensitivity. MARK2 is phosphorylated by cyclin-dependent kinase 1 (CDK1) during paclitaxel-induced mitotic arrest and normal mitosis. MARK2 inhibition did not affect growth under normal conditions, but greatly sensitized PDAC cells to paclitaxel-induced apoptosis. Mechanistically, our findings also suggest that MARK2 controls paclitaxel chemosensitivity by regulating class IIa HDACs (histone deacetylase). MARK2 directly phosphorylates HDAC4 on multiple sites upon paclitaxel treatment. Inhibition (with knockdown or inhibitors) of HDACs significantly enhanced paclitaxel-induced cell death in a MARK2-phosphorylation dependent manner in PDAC cells. MARK2-phosphorylated HDAC4 positively regulates YAP (the transcriptional coactivator of the Hippo pathway) activity and controls expression of YAP target genes induced by paclitaxel. MARK2, class IIa HDACs, and YAP expression levels are upregulated and positively correlated in PDAC patients. Importantly, combination of HDAC inhibition (Vorinostat/SAHA, FDA-approved) and paclitaxel overcomes paclitaxel-resistance in preclinical PDAC animal models. Together, our findings reveal the MARK2-HDAC-YAP axis as a druggable target for overcoming paclitaxel resistance in PDAC. Citation Format: Yongji Zeng, Yuanhong Chen, Jixin Dong. Targeting MARK2-HDAC-YAP signaling to overcome paclitaxel resistance in PDAC [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 3691A.

131P Abrogation of paclitaxel chemo-resistance via epigenetic immune checkpoints regulation in triple negative breast cancer

Chemotherapy is the standard monotherapy of Triple Negative Breast Cancer (TNBC) and a main cause for chemo-resistant cases. Anti-programmed death (PDL1) and Anti-Mesothelin (MSLN) therapies has thrust the immunotherapy into spotlight showing a potential cure for TNBC, yet they are understudied. Moreover, MSLN itself was proved to contribute in paclitaxel chemoresistance. MiR-34a along with our previously characterized LncRNA-XIST were proved to be potent tumor-suppressors in TNBC cell lines. This study aims to investigate the role of PD-L1 and MSLN epigenetic regulation in increasing chemo-sensitivity of paclitaxel in TNBC.

FNDC5 promotes paclitaxel sensitivity of non-small cell lung cancers via inhibiting MDR1

Therapeutic benefits and clinical application of paclitaxel for treating non-small cell lung cancers (NSCLCs) are extremely hampered due to the chemoresistance. A recent study found that fibronectin type III domain-containing protein 5 (FNDC5) was downregulated in NSCLCs cells and negatively correlated with the clinicopathological characteristics in patients with NSCLCs. However, the role and potential molecular basis for FNDC5 in paclitaxel sensitivity of NSCLCs remain unclear. Paclitaxel-sensitive or resistant NSCLCs cell lines were exposed to small interfering RNA against FNDC5 (siFndc5) or recombinant irisin in the presence or absence of paclitaxel. NSCLCs cell lines have decreased FNDC5 expression compared with the normal human lung epithelial cells, which was further downregulated in paclitaxel-resistant cells. Irisin treatment suppressed, whereas Fndc5 silence promoted NSCLCs cells proliferation under basal conditions. Besides, we found that FNDC5 increased paclitaxel chemosensitivity in paclitaxel-sensitive or resistant NSCLCs cell lines via downregulating multidrug resistance protein 1 (MDR1). Further studies revealed that FNDC5 inhibited MDR1 expression via blocking nuclear factor-κB (NF-κB) activation. FNDC5 promotes paclitaxel sensitivity of NSCLCs cells via inhibiting NF-κB/MDR1 signaling, and FNDC5 might be a novel therapeutic target for the treatment of NSCLCs.

The MRVI1-AS1/ATF3 signaling loop sensitizes nasopharyngeal cancer cells to paclitaxel by regulating the Hippo-TAZ pathway.

Long non-coding RNA (lncRNA) plays an important role in malignant tumor occurrence, development, and chemoresistance, but the mechanism of how they affect nasopharyngeal cancer (NPC) paclitaxel chemosensitivity is unclear. In this study, lncRNA array of CNE-1 and HNE-2 paclitaxel-resistant cells and their parental strains revealed that the paclitaxel-resistant strains had significantly lower MRVI1-AS1 (murine retrovirus integration site 1 homolog antisense RNA 1) expression than the parental strains, and that MRVI1-AS1 overexpression in vitro and in vivo increased paclitaxel chemosensitivity. Further, MRVI1-AS1 upregulated ATF3 (activating transcription factor 3) by simultaneously inhibiting miR-513a-5p (microRNA-513a-5p) and miR-27b-3p expression levels to increase NPC paclitaxel chemosensitivity. Chromatin immunoprecipitation and quantitative real-time PCR showed that ATF3 could feed-back MRVI1-AS1 regulation positively. Furthermore, MRVI1-AS1 and ATF3 could form a positive feedback loop, which promoted the expression of RASSF1 (Ras association domain family member 1), a Hippo-TAZ (tafazzin) signaling pathway regulatory factor, thereby inhibiting TAZ expression. The MTT (3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyltetrazolium bromide) assay and flow cytometry showed that the decreased TAZ increased NPC cell paclitaxel chemosensitivity. Overall, the results indicate that the MRVI1-AS1/ATF3 signaling pathway can increase NPC paclitaxel chemosensitivity by modulating the Hippo-TAZ signaling pathway. Therefore, targeting the loop may be a new NPC treatment strategy.

Adenosine triphosphate-based chemotherapy response assay predicts long-term survival of primary epithelial ovarian cancer.

The aim of this study is to analyze the long-term relapse-free survival and overall survival outcomes of primary ovarian cancer patients using adenosine triphosphate-based chemotherapy response analysis. In total, 162 primary epithelial ovarian cancer patients who underwent chemotherapy response assay for carboplatin, cisplatin, and paclitaxel by adenosine triphosphate-based chemotherapy response analysis prior to chemotherapy between December 2006 and November 2016 were retrospectively reviewed. Chemosensitivity with single or combined three agents and clinical characteristics of patients were studied to understand their correlation with long-term relapse-free survival and overall survival. Median follow-up time was 61.4 (range 1 - 130) months. Univariate analysis showed the paclitaxel-sensitive group (HR = 0.625, 95%CI = 0.393 to 0.994), combined carboplatin and paclitaxel-sensitive group (HR = 0.574, 95%CI = 0.352 to 0.937), and combined carboplatin, cisplatin, and paclitaxel-sensitive group (HR = 0.489, 95%CI = 0.295 to 0.810) were highly associated with better relapse-free survival than their corresponding non-sensitive groups. The carboplatin-sensitive group (HR = 0.533, 95%CI = 0.303 to 0.939), cisplatin-sensitive group (HR = 0.433. 95%CI = 0.251 to 0.748), and combined carboplatin- and cisplatin-sensitive group (HR = 0.286, 95%CI = 0.142 to 0.576) were highly associated with better overall survival than their corresponding non-sensitive groups. Combined carboplatin, cisplatin, and paclitaxel chemosensitivity, together with International Federation of Gynecology and Obstetrics (FIGO) stage were independent predictors for relapse-free survival. Single or combined chemosensitivity of cisplatin and/or carboplatin, together with residual tumor size and FIGO stage, were significant independent predictors for overall survival on a multivariate hazard model. Paclitaxel sensitivity is a prognostic factor of long-term relapse-free survival in patients with epithelial ovarian cancer, but platinum sensitivity is a more important prognostic factor for long-term overall survival.

Cyclin-dependent kinase 1-mediated AMPK phosphorylation regulates chromosome alignment and mitotic progression.

AMP-activated protein kinase (AMPK), a heterotrimeric serine/threonine kinase and cellular metabolic sensor, has been found to regulate cell cycle checkpoints in cancer cells in response to energetic stress, to harmonize proliferation with energy availability. Despite AMPK's emergent association with the cell cycle, it still has not been fully delineated how AMPK is regulated by upstream signaling pathways during mitosis. We report, for the first time, direct CDK1 phosphorylation of both the catalytic α1 and α2 subunits, as well as the β1 regulatory subunit, of AMPK in mitosis. We found that AMPK-knockout U2OS osteosarcoma cells have reduced mitotic indexes and that CDK1 phosphorylation-null AMPK is unable to rescue the phenotype, demonstrating a role for CDK1 regulation of mitotic entry through AMPK. Our results also denote a vital role for AMPK in promoting proper chromosomal alignment, as loss of AMPK activity leads to misaligned chromosomes and concomitant metaphase delay. Importantly, AMPK expression and activity was found to be critical for paclitaxel chemosensitivity in breast cancer cells and positively correlated with relapse-free survival in systemically treated breast cancer patients.

P16 Methylation Leads to Paclitaxel Resistance of Advanced Non-Small Cell Lung Cancer.

Paclitaxel-based chemotherapy is widely used as the first-line treatment for non-small cell lung cancer (NSCLC). However, only 20%-40% of patients have shown sensitivity to paclitaxel. This study aimed to investigate whether P16 methylation could be used to predict paclitaxel chemosensitivity of NSCLC. Advanced NSCLC (N=45) were obtained from patients who were enrolled in a phase-III randomized paclitaxel-based clinical trial. Genomic DNA samples were extracted from the biopsies prior to chemotherapy. P16 methylation was detected using MethyLight. The association between P16 methylation and the sensitivity of paclitaxel in cell lines was determined by in vitro assay using a P16-specific DNA demethylase (P16-TET) and methyltransferase (P16-Dnmt). The total response rate of the low-dose paclitaxel-based chemo-radiotherapy was significantly lower in P16 methylation-positive NSCLCs than that in the P16 methylation-negative NSCLCs (2/15 vs. 16/30: adjusted OR=0.085; 95%CI, 0.012-0.579). Results revealed that P16 demethylation significantly decreased paclitaxel resistance of lung cancer H1299 cells (IC50 values decreased from 2.15 to 1.13 µg/ml, P<0.001). In contrast, P16-specific methylation by P16-Dnmt significantly increased paclitaxel resistance of lung cancer HCC827 cells and gastric cancer BGC823 cells (IC50 values increased from 18.2 to 24.0 ng/ml and 0.18 to 0.81 µg/ml, respectively; P=0.049 and <0.001, respectively). The present results suggest that P16 methylation may lead to paclitaxel resistance and be a predictor of paclitaxel chemosensitivity of NSCLC.

Gambogenic acid reverses P-glycoprotein mediated multidrug resistance in HepG2/Adr cells and its underlying mechanism

Gambogenic acid (GNA), an active ingredient isolated from Gamboge, which possesses diverse antitumor effects in vivo and vitro. Here we were mainly designed to understand the role of GNA in drug resistance in HepG2/Adr cells. The alteration of cytotoxic drugs IC50 was examined using the MTT method. Cell apoptosis and uptake of P-glycoprotein (P-gp) substrates were measured under a flow cytometry and fluorescence microscope, respectively. Moreover, the ATPase activity, the expression of P-gp and P-gp-related proteins were also investigated. Results of the MTT method indicated that GNA increased the chemosensitivity of doxorubicin (DOX) and paclitaxel (PTX) in the HepG2/Adr cells and promoted the cell apoptosis in the presence of DOX. Meanwhile, it was also increased the retention of P-gp substrates DOX and Rhodamine 123 (Rho-123) while did not affect the ATPase activity. Furthermore, the down-regulation of P-gp expression could be contributed to multidrug resistance (MDR) upon a reversal concentration of 0.8 μg/mL GNA. Mechanistically, the expression of P-gp was reduced by GNA may result from the inhibition of the NF-kB and MAPK pathway. Collectively, GNA could be a potential inhibitor to reverse P-gp-mediated MDR in liver cancer therapy.