Molecular mechanisms of cisplatin resistance in cervical cancer

Efficacy and Safety of Pembrolizumab in Previously Treated Advanced Cervical Cancer: Results From the Phase II KEYNOTE-158 Study

PURPOSE

KEYNOTE-158 ( ClinicalTrials.gov identifier: NCT02628067) is a phase II basket study investigating the antitumor activity and safety of pembrolizumab in multiple cancer types. We present interim results from patients with previously treated advanced cervical cancer.

PATIENTS AND METHODS

Patients received pembrolizumab 200 mg every 3 weeks for 2 years or until progression, intolerable toxicity, or physician or patient decision. Tumor imaging was performed every 9 weeks for the first 12 months and every 12 weeks thereafter. The primary end point was objective response rate (ORR), assessed per Response Evaluation Criteria in Solid Tumors (version 1.1) by independent central radiologic review. Safety was a secondary end point.

RESULTS

Ninety-eight patients were treated. Median age was 46.0 years (range, 24 to 75 years), and 65.3% of patients had Eastern Cooperative Oncology Group performance status of 1. Eighty-two patients (83.7%) had programmed death-ligand 1 (PD-L1)-positive tumors (combined positive score ≥ 1), 77 having previously received one or more lines of chemotherapy for recurrent or metastatic disease. Median follow-up was 10.2 months (range, 0.6 to 22.7 months). ORR was 12.2% (95% CI, 6.5% to 20.4%), with three complete and nine partial responses. All 12 responses were in patients with PD-L1-positive tumors, for an ORR of 14.6% (95% CI, 7.8% to 24.2%); 14.3% (95% CI, 7.4% to 24.1%) of these responses were in those who had received one or more lines of chemotherapy for recurrent or metastatic disease. Median duration of response was not reached (range, ≥ 3.7 to ≥ 18.6 months). Treatment-related adverse events occurred in 65.3% of patients, and the most common were hypothyroidism (10.2%), decreased appetite (9.2%), and fatigue (9.2%). Treatment-related grade 3 to 4 adverse events occurred in 12.2% of patients.

CONCLUSION

Pembrolizumab monotherapy demonstrated durable antitumor activity and manageable safety in patients with advanced cervical cancer. On the basis of these results, the US Food and Drug Administration granted accelerated approval of pembrolizumab for patients with advanced PD-L1-positive cervical cancer who experienced progression during or after chemotherapy.

Upregulation of MTA1 expression by human papillomavirus infection promotes CDDP resistance in cervical cancer cells via modulation of NF-κB/APOBEC3B cascade

OBJECTIVE

Compelling evidence establishes the etiological role of viral proteins E6 and E7 of high-risk human papillomaviruses (HPV) in cervical carcinogenesis, but their contribution in chemoresistance that leads to advanced metastatic lesions remains poorly defined. Since metastasis-associated protein 1 (MTA1) upregulation and augmentation of APOBEC3B expression are both strongly associated with cervical cancer (CCa) development, and both molecules have been shown to be functionally associated with NF-κB pathway, we therefore sought to investigate the potential mechanistic link between MTA1, APOBEC3B and NF-κB during the pathogenesis of cisplatin (CDDP) resistance in HPV-positive CCa cells.

METHODS

MTA1 expression was assessed in HPV-transfected CCa cells using quantitative RT-PCR and immunoblotting. Effects of MTA1 deregulation on CDDP chemosensitivity in CCa cells were determined by measuring cell viability, apoptosis and in vivo oncogenic capacity. Finally, we studied the transcriptional regulation of the antiviral DNA cytosine deaminase APOBEC3B by MTA1 using multiple approaches including DNA deaminase activity assay, luciferase reporter assay, chromatin immunoprecipitation, co-immunoprecipitation and transient/stable transfection, at the molecular and functional levels.

RESULTS

Expression levels of MTA1 were significantly induced in HPV-positive CCa cells. Transduction experiments showed that the E6 oncoprotein alone was sufficient to cause MTA1 upregulation. Moreover, MTA1 knockdown potentiated CDDP sensitivity in highly metastatic CCa cells. Mechanistically, MTA1 acted as an indirect upstream modulator of APOBEC3B transcription during the pathogenesis of CDDP chemoresistance. HPV-mediated stimulation of APOBEC3B expression was accompanied by the enhanced recruitment of Iκκ α/β and p65 to the NF-κB consensus sites in the APOBEC3B promoter, and this recruitment was substantially abrogated by MTA1 siRNA treatment.

CONCLUSIONS

These findings reveal an obligatory coregulatory role of MTA1 in the indirect regulation of APOBEC3B expression via classical NF-κB pathway, and also suggest that inhibition of MTA1/NF-κB/APOBEC3B cascade may be repositioned to suppress cancer mutagenesis, dampen tumor evolution, and decrease the probability of adverse outcomes from CDDP resistance in CCa.

microRNAs: New prognostic, diagnostic, and therapeutic biomarkers in cervical cancer

Cervical cancer is as a kind of cancer beginning from the cervix. Given that cervical cancer could be observed in women who infected with papillomavirus, regular oral contraceptives, and multiple pregnancies. Early detection of cervical cancer is one of the most important aspects of the therapy of this malignancy. Despite several efforts, finding and developing new biomarkers for cervical cancer diagnosis are required. Among various prognostic, diagnostic, and therapeutic biomarkers, miRNA have been emerged as powerful biomarkers for detection, treatment, and monitoring of response to therapy in cervical cancer. Here, we summarized various miRNAs as an employable platform for prognostic, diagnostic, and therapeutic biomarkers in the treatment of cervical cancer.

Inhibition of cytosolic phospholipase A2 alpha increases chemosensitivity in cervical carcinoma through suppressing β-catenin signaling

Cytosolic phospholipase A2alpha (cPLA2α) is a key mediator of tumorigenesis. In this study, by using a combination of pharmacological and genetic approaches in cell models and patient samples, we identify cPLA2α as a selective target to increase chemosensitivity in cervical cancer. We found that transcript and protein levels of cPLA2α but not other forms of cPLA2 (e.g., cPLA2β and cPLA2αδ) were consistently increased in all tested malignant cervical cancer cells and tissues compared to normal counterparts, suggesting that cPLA2α upregulation is a common feature in cervical cancer. We further found that promoting growth and survival rather than invasion were the predominant roles of cPLA2α on cervical cancer. In addition, chemotherapeutic agents achieved ~100% inhibition efficacy in cPLA2α-depleted cervical cancer cells, demonstrating the important role of cPLA2α in chemoresistance. Importantly, we identify that β-catenin is critically involved in the molecular mechanism of cPLA2α's action in cervical cancer. In summary, our work demonstrates the multiple essential roles of cPLA2α in cervical cancer, particularly in chemoresistance, via a β-catenin-dependent manner. Our work also suggests that targeting cPLA2α has a therapeutic value in overcoming chemoresistance in cervical cancer or other cPLA2α-regulated cancers.

Review on Pharmacology of Cisplatin: Clinical Use, Toxicity and Mechanism of Resistance of Cisplatin

Cisplatin is a chemotherapeutic drug that has been used in the treatment of various types of human cancers such as ovarian, lung, head and neck, testicular and bladder. Cisplatin has demonstrated efficacy against various types of cancers such as germ cell tumors, sarcomas, carcinomas as well as lymphomas. The current study presents a pharmacological review on the drug including its mechanism of action, resistance mechanism, and toxicity as well as its clinical applications. The mechanism of action of cisplatin has been associated with ability to crosslink with the urine bases on the DNA to form DNA adducts, preventing repair of the DNA leading to DNA damage and subsequently induces apoptosis within cancer cells. However, the drug exhibits certain level of resistance including increased repair of the damaged DNA, reduction in the accumulation of the drug intracellular and cytosolic inactivation of cisplatin. The drug is also characterized by various toxic side effects including nausea, nephrotoxicity, Cardiotoxicity, hepatotoxicity and neurotoxicity. Due various side effects as well as drug resistance, other anti-cancer drugs that contain platinum such as carboplatin and oxaliplatin among others have been used in combination with cisplatin in chemotherapeutic treatment of cancer. Strong evidence from research has demonstrated higher efficacy of combination of chemotherapies of cisplatin together with other drugs in overcoming drug resistance and in reducing toxic effects as well. Future studies that explore combinational techniques that target various mechanisms such as reduction in the uptake of cisplatin as well as inflammation could enhance efficacy of cisplatin.

An Olive Leaf Extract Rich in Polyphenols Promotes Apoptosis in Cervical Cancer Cells by Upregulating p21Cip/WAF1 Gene Expression

Most of the common drugs used to treat the cervical cancer, which main etiological factor is the HPV infection, cause side effects and intrinsic/acquired resistance to chemotherapy. In this study we investigated whether an olive leaf extract (OLE), rich in polyphenols, was able to exert anti-tumor effects in human cervical cancer cells (HeLa). MTT assay results showed a reduction of HeLa cells viability OLE-induced, concomitantly with a gene and protein down-regulation of Cyclin-D1 and an up-regulation of p21, triggering intrinsic apoptosis. OLE reduced NFkB nuclear translocation, which constitutive activation, stimulated by HPV-oncoproteins, promotes cancer progression and functional studies revealed that OLE activated p21^Cip/WAF1 in a transcriptional-dependent-manner, by reducing the nuclear recruitment of NFkB on its responsive elements. Furthermore, OLE treatment counteracted epithelial-to-mesenchymal-transition and inhibited anchorage-dependent and -independent cell growth EGF-induced. Finally, MTT assay results revealed that OLE plus Cisplatin strengthened the reduction of cells viability Cisplatin-induced, as OLE inhibited NFkB, AkT and MAPK pathways, all involved in Cisplatin chemoresistance. In conclusion, we demonstrated that in HeLa cells OLE exerts pro-apoptotic effects, elucidating the molecular mechanism and that OLE could mitigate Cisplatin chemoresistance. Further studies are needed to explore the potential coadiuvant use of OLE for cervical cancer treatment.

Astragali radix total flavonoid synergizes cisplatin to inhibit proliferation and enhances the chemosensitivity of laryngeal squamous cell carcinoma

Laryngeal squamous cell carcinoma (LSCC) is the most common head and neck cancer. Astragali radix extracts play crucial roles in the regulation of cancer progression. However, the role of Astragali radix extracts in LSCC and the related mechanisms remains unclear. Here, we evaluated the inhibitory effects of the combined use of Astragali radix total flavonoid (TFA) and cisplatin (CDDP) on an LSCC mouse model by pharmacodynamics. Ultra-high-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) was employed to define the prototype of TFA in vivo. The potential drug targets were identified through the integrative analysis of LSCC microarrays, RNA sequencing data and the main bioactive component of TFA. Furthermore, a protein–protein interaction network, compound–target network and target–pathway network were constructed based on the prototype and potential drug targets to identify the main targets and pathways. Animal experiments showed that TFA has significant synergistic antitumor activity with cisplatin and attenuates the nephrotoxicity caused by CDDP chemotherapy, improving the survival of LSCC-bearing mice. Using UPLC-MS/MS, we identified 8 constituents of TFA in experimental mice serum: formononetin, ononin, calycosin, calycosin-7-O-β-D-glucoside, 7,2′-dihydroxy-3′,4′-dimethoxyisoflavan, 7,2′-dihydroxy-3′,4′-dimethoxyisoflavaneglucoside, 3-hydroxy-9,10-dimethoxypterocarpan and 9,10-dimethoxyptercarpan-3-O-β-d-glucoside. Integrative analysis predicted 19 target genes for TFA constituents, and the target genes were mainly involved in the EGFR-related cancer signaling, metabolism and oxidative stress. Collectively, these findings highlight the role of TFA in the regulation of LSCC and provide potential targets for a high-efficiency and low-toxicity therapeutic strategy of LSCC.

Astragali radix total flavonoid synergizes with cisplatin to inhibit tumorigenesis of laryngeal squamous cell carcinoma.

Phytochemicals: Current strategy to sensitize cancer cells to cisplatin

Cisplatin-based chemotherapeutic regimens are the most frequently used adjuvant treatments for many types of cancer. However, the development of chemoresistance to cisplatin results in treatment failure. Despite the significant developments in understanding the mechanisms of cisplatin resistance, effective strategies to enhance the chemosensitivity of cisplatin are lacking. Phytochemicals are naturally occurring plant-based compounds that can augment the anti-cancer activity of cisplatin, with minimal side effects. Notably, some novel phytochemicals, such as curcumin, not only increase the efficacy of cisplatin but also decrease toxicity induced by cisplatin. However, the exact mechanisms underlying this process remain unclear. In this review, we discussed the progress made in utilizing phytochemicals to enhance the anti-cancer efficacy of cisplatin. We also presented some ideal phytochemicals as novel agents for counteracting cisplatin-induced organ damage.

Cervical cancer cell lines are sensitive to sub-erythemal UV exposure

High risk human papillomavirus (HPV) infections are the causative agent in virtually every cervical cancer as well as a host of other anogenital and oropharyngeal malignancies. These viruses must activate DNA repair pathways to facilitate their replication, while avoiding the cell cycle arrest and apoptosis that can accompany DNA damage. HPV oncoproteins facilitate each of these goals, but also reduce genome stability. Our data dissect the cytotoxic and cytoprotective characteristics of HPV oncogenes in cervical cancer cells. These data show that while the transformation of keratinocytes by HPV oncogene leaves these cells more sensitive to UV, the oncogenes also protect against UV-induced apoptosis. Cisplatin and UV resistant cervical cancer cell lines were generated and probed for their sensitivity to genotoxic agents. Cervical cancer cells can acquire resistance to one DNA crosslinking agent (UV or cisplatin) without gaining broad tolerance of crosslinked DNA. Further, cisplatin resistance may or may not result in sensitivity to PARP1 inhibition.

γ-secretase inhibitor DAPT mitigates cisplatin-induced acute kidney injury by suppressing Notch1 signaling

Organ toxicity, including kidney injury, limits the use of cisplatin for the treatment of multiple human cancers. Hence, interventions to alleviate cisplatin-induced nephropathy are of benefit to cancer patients. Recent studies have demonstrated that pharmacological inhibition of the Notch signaling pathway enhances cisplatin efficacy against several cancer cells. However, whether augmentation of the anti-cancer effect of cisplatin by Notch inhibition comes at the cost of increased kidney injury is unclear. We show here that treatment of mice with cisplatin resulted in a significant increase in Notch ligand Delta-like 1 (Dll1) and Notch1 intracellular domain (N1ICD) protein expression levels in the kidneys. N-[N-(3,5-difluorophenacetyl)-L-alanyl]-S-phenylglycine t-butyl ester (DAPT), a γ-secretase inhibitor reversed cisplatin-induced increase in renal N1ICD expression and plasma or urinary levels of predictive biomarkers of acute kidney injury (AKI). DAPT also mitigated cisplatin-induced tubular injury and reduction in glomerular filtration rate. Real-time multiphoton microscopy revealed marked necrosis and peritubular vascular dysfunction in the kidneys of cisplatin-treated mice which were abrogated by DAPT. Cisplatin-induced Dll1/Notch1 signaling was recapitulated in a human proximal tubule epithelial cell line (HK-2). siRNA-mediated Dll1 knockdown and DAPT attenuated cisplatin-induced Notch1 cleavage and cytotoxicity in HK-2 cells. These data suggest that Dll1-mediated Notch1 signaling contributes to cisplatin-induced AKI. Hence, the Notch signaling pathway could be a potential therapeutic target to alleviate renal complications associated with cisplatin chemotherapy.

LncRNA XLOC_006390 facilitates cervical cancer tumorigenesis and metastasis as a ceRNA against miR-331-3p and miR-338-3p

OBJECTIVE

Cervical cancer is one of the most common malignant tumors. Our previous results showed that long non-coding RNA (lncRNA) XLOC_006390 plays an important role in cervical cancer. In this study, we have explored the mechanism of action of lncRNA XLOC_006390.

METHODS

LncRNA XLOC_006390 was proposed to exercise its function as a competing endogenous RNA (ceRNA), and its potential targeted miRNAs was predicted through the database LncBase Predicted v.2. Two miRNAs, miR-331-3p, and miR-338-3p, were chosen for the study. Expression of miRNAs and lncRNA in cervical cancer cells and tissues was detected by reverse transcription polymerase chain reaction. To determine the correlation, silencing of XLOC_006390, over-expression of miR-331-3p, and miR-338-3p was performed in SiHa and Caski cell lines, respectively.

RESULTS

Based on the interactive effect between miRNA and lncRNA, miR-331-3p and miR-338-3p were significantly downregulated in cervical cancer cells and tissues, and their expression levels were negatively related to that of lncRNA. Our results also showed that the expression of miR-331-3p target gene NRP2, miR-338-3p target genes PKM2, EYA2 was significantly downregulated when the XLOC_006390 was knocked down. Further, XLOC_006390 was found to facilitate cervical cancer tumorigenesis and metastasis by downregulating miR-331-3p and miR-338-3p expression.

CONCLUSION

Taken together, our study demonstrated that XLOC_006390 may serve as a ceRNA and reversely regulates the expression of miR-331-3p and miR-338-3p, thus facilitating cervical cancer tumorigenesis and metastasis.

Role of DDX53 in taxol-resistance of cervix cancer cells in vitro

Cancer/Testis antigen DDX53 shows high expression level in various tumors and is involved in anti-cancer drug resistance. However, the functional study of DDX53 in cervix cancer remains unknown. In this study, the role of DDX53 in taxol-resistance of cervix cancer cells was investigated. In taxol-resistant Hela^TR cells, DDX53 was significantly increased as compared to the parental HeLa cells. Hela^TR cells also showed upregulation of multidrug resistant gene MDR1, invasive characteristics and decreased apoptosis. In addition, increased autophagy level was observed in Hela^TR cells. Overexpression of DDX53 in HeLa and SiHa markedly led to greater resistance to taxol and cisplatin, whereas knockdown of DDX53 in Hela^TR cells restored sensitivity, demonstrating that DDX53 regulated taxol resistance in cervix cancer cells. DDX53 overexpression in HeLa and SiHa cells enhanced invasion, migration and anchorage independent growth, DDX53 knockdown showed inverse effects in HeLa^TR cells. When DDX53 expression was suppressed by siRNA, autophagic flux and drug resistance of Hela^TR cells were decreased. In addition, DDX53 was upregulated in cervix cancer tissues from patient with a glassy cell carcinoma of cervix. Taken together, these results suggest that DDX53 plays a critical role in taxol-resistance by activating autophagy and a potential therapeutic target for the treatment of taxol-resistant cervix cancer.

S100A9 regulates cisplatin chemosensitivity of squamous cervical cancer cells and related mechanism

OBJECTIVE

Our previous research has shown that the expression of S100 calcium-binding protein A9 (S100A9) in tumor cells was associated with neoadjuvant chemotherapy sensitivity in cervical squamous cell carcinoma. In the present study, we altered the expression of S100A9 through infecting lentivirus, investigated its effect on the chemosensitivity to cisplatin of cervical cancer cells and then made a primary exploration of the involved mechanism.

MATERIALS AND METHODS

Lentivirus was employed to upregulate and downregulate S100A9 expression in SiHa cells. The protein expression level of apoptotic-related proteins Bcl-2 and Bax, drug resistance-related proteins multiple drug resistance protein 1 (MRP1), P glycoprotein (P-gp), glutathione-S-transferase-π (GST-π), lung resistance-related protein (LRP), and FOXO1 signaling pathway related proteins was detected by Western blot. The CCK-8 assay was used to examine chemosensitivity to cisplatin, and the proportion of apoptosis cells was analyzed by the flow cytometry.

RESULTS

S100A9 overexpression could obviously increase the IC50 value of SiHa cells to cisplatin and decrease the apoptosis rate induced by cisplatin. Downregulation of S100A9 led to the opposite results. In S100A9 overexpression SiHa cells, the expression level of Bcl-2, LRP, GST-π, p-AKT, p-ERK, p-FOXO1, and Nanog was significantly increased, while FOXO1 expression was decreased. The opposite results were observed in S100A9 knockdown SiHa cells.

CONCLUSION

Downregulation of S100A9 could significantly increase apoptosis rate, resulting in enhancing sensitivity of SiHa cells to cisplatin, which may be related to Bcl-2, GST-π, and LRP protein and by altering the AKT/ERK-FOXO1-Nanog signaling pathway.

MicroRNA-7-5p Promotes Cisplatin Resistance of Cervical Cancer Cells and Modulation of Cellular Energy Homeostasis by Regulating the Expression of the PARP-1 and BCL2 Genes

Background

Resistance to cisplatin results in recurrence or relapse of cervical cancer in women. An understanding of the mechanisms of cisplatin resistance will be important to improve the efficacy of cisplatin treatment. The aim of this study was to investigate the role of microRNA-7-5p (mir-7-5p) in cisplatin-resistant cervical cancer cells in vitro.

Material/Methods

The expression levels of miR-7-5p were detected in cisplatin-resistant cervical cancer cells, HeLa, and SiHa cells (HPV16-positive), and in clinical tissue samples, using miR-7-5p inhibition and a luciferase reporter assay. Fifteen paired cervical cancer tissue samples and adjacent normal cervical tissues were obtained from 15 patients who underwent surgery for cervical cancer. Western blot and flow cytometry were used to investigate cell apoptosis. The expression of mir-7-5p was detected by quantitative real-time reverse transcription-polymerase chain reaction (qRT-PCR).

Results

The level of miR-7-5p was increased in cisplatin-resistant HeLa and SiHa cervical cancer cells. Increased expression of miR-7-5p inhibited DNA repair by modulating the expression of poly (ADP-ribose) polymerase 1 (PARP-1), reducing energy consumption, and promoting autophagy via suppression of the expression of Bcl-2. These findings supported that increasing energy generation and reducing energy consumption, resulted in miR-7-5p maintaining energy homeostasis during cisplatin treatment.

Conclusions

The findings of this study showed that there was a protective role of miR-7-5p in cervical cancer cells treated with cisplatin and that miR-7-5p expression maintained energy homeostasis in cisplatin-resistant cervical cancer cells. However, miR-7-5p reduced energy consumption via inhibiting PARP-1 expression, and miR-7-5p increased energy generation by suppressing the expression of Bcl-2.

Inhibiting 6-phosphogluconate dehydrogenase enhances chemotherapy efficacy in cervical cancer via AMPK-independent inhibition of RhoA and Rac1

BACKGROUND

The oxidative pentose phosphate pathway (PPP) is essential for cancer metabolism and growth. However, the contribution of 6-phosphogluconate dehydrogenase (6PGD), a key enzyme of PPP, to cervical cancer development remains largely unknown.

METHODS

mRNA and protein levels of 6PGD were analyzed in cervical cancer cells and tissues derived from patients and compared to normal counterparts. Using cell culture system and xenograft mouse model, the functions of 6PGD in cervical cancer are determined and its molecular mechanism is analyzed. 6PGD inhibitor physcion and siRNA knockdown were used.

RESULTS

In this work, we demonstrate that 6PGD is aberrantly upregulated and activated in cervical cancer cells and patient tissues compared to normal counterparts. Using different approaches and preclinical models, we show that 6PGD inhibition decreases growth and migration, and enhances chemosensitivity in cervical cancer. Mechanistically, inhibition of 6PGD activates AMP-activated protein kinase (AMPK) and decreases RhoA and Rac1 activities. AMPK depletion significantly reduces the effects of 6PGD inhibition in decreasing RhoA and Rac1 activities, growth and migration in cervical cancer cells.

CONCLUSIONS

Our work is the first to demonstrate the aberrant expression of 6PGD and its predominant roles in cervical cancer cell growth and migration, via a AMPK-dependent activation. Our findings suggest 6PGD as a potential therapeutic target to enhance chemosensitivity in cervical cancer.

In Vitro Study of Antitumor Effect of Antimicrobial Peptide Tachyplesin I in Combination with Cisplatin

We studied combined effect of β-hairpin antimicrobial peptide tachyplesin I and cytotoxic agent cisplatin on tumor and normal human cell lines. MTT assay and flow cytometry showed that tachyplesin I selectively sensitized cancer cells to cisplatin in specified concentration ratios. In vitro experiments demonstrated that combined use of tachyplesin I and cisplatin allows decreasing the effective dose of the cytostatic thus reducing nonspecific toxicity.

Glucose-Related Protein 78 Expression and Its Effects on Cisplatin-Resistance in Cervical Cancer

Background

GRP78, the 78-kDa glucose-regulated protein, occupies a significant position in endoplasmic reticulum stress. Emerging evidences have shown that GRP78 induces chemoresistance in several tumors; however, the role of GRP78 in cervical cancer (CVC) still needs to be elucidated clearly.

Material/Methods

In the present study, we evaluated the expression levels of GRP78 in CVC tissues collected from patients through immunocytochemistry, western blot, and real-time PCR. To explore the exact role of GRP78 in CVC cells in the presence of cisplatin, we generated GRP78 knockdown CVC cells through small interfering RNA. After transfection, the apoptosis rate was assessed by flow cytometry. Then the expression levels of caspase-3, CHOP, and Bcl-2 in GRP78 knockdown cells were determined by western blot.

Results

The GRP78 levels in CVC tissues were increased significantly. Three types of CVC cells HeLa, SiHa, and C33A were treated with different concentrations of cisplatin and cultured for 12 hours, 24 hours, and 48 hours respectively. And SiHa cells exhibited the highest resistance to cisplatin at all time. Specifically, after 25 μM cisplatin treatment, more than 80% of C33A cells underwent apoptosis, whereas the apoptotic rate of SiHa cells was only 30–40%. Data suggested that GRP78 silencing increased chemo-sensitivity and improved the effects of cisplatin-induced apoptosis in SiHa cells. Moreover, inhibition of GRP78 could upregulate caspase-3 and CHOP expression and downregulate Bcl-2 expression.

Conclusions

GRP78 may represent a key bio-marker of CVC and silencing GRP78 may strengthen the resistance against cisplatin. GRP78 may be a potential molecular target for CVC therapies in future.

SOX9/miR-130a/CTR1 axis modulates DDP-resistance of cervical cancer cell

Cisplatin (DDP) -based chemotherapy is a standard strategy for cervical cancer, while chemoresistance remains a huge challenge. Copper transporter protein 1 (CTR1), a copper influx transporter required for high affinity copper (probably reduced Cu I) transport into the cell, reportedly promotes a significant fraction of DDP internalization in tumor cells. In the present study, we evaluated the function of CTR1 in the cell proliferation of cervical cancer upon DDP treatment. MicroRNAs (miRNAs) have been regarded as essential regulators of cell proliferation, apoptosis, migration, as well as chemoresistance. By using online tools, we screened for candidate miRNAs potentially regulate CTR1, among which miR-130a has been proved to promote cervical cancer cell proliferation through targeting PTEN in our previous study. In the present study, we investigated the role of miR-130a in cervical cancer chemoresistance to DDP, and confirmed the binding of miR-130a to CTR1. SOX9 also reportedly act on cancer chemoresistance. In the present study, we revealed that SOX9 inversely regulated miR-130a through direct targeting the promoter of miR-130a. Consistent with previous studies, SOX9 could affect cervical cancer chemoresistance to DDP. Taken together, we demonstrated a SOX9/miR-130a/CTR1 axis which modulated the chemoresistance of cervical cancer cell to DDP, and provided promising targets for dealing with the chemoresistance of cervical cancer.

Inhibition of isoprenylcysteine carboxylmethyltransferase sensitizes common chemotherapies in cervical cancer via Ras-dependent pathway

Isoprenylcysteine carboxylmethyltransferase (Icmt) catalyzes the last step of post-translational protein prenylation, which is essential for the stability and proper functions of many oncogenic proteins, such as Ras. Despite extensive studies on the roles of Icmt in tumor transformation and progression, little is known on the involvement ofIcmt in the development of tumor resistance to chemotherapy. Here we show the upregulation of Icmt as a persistent response to chemotherapy in cervical cancer cells. In-depth functional analysis demonstrated that Icmt inhibition significantly inhibited growth, induced apoptosis and augmented the inhibitory effects of chemotherapy drugs in cervical cancer in cell culture system and xenograft mouse model. Importantly, combination of Icmt specific inhibitor cysmethynil with doxorubicin or paclitaxel at sublethal concentration achieved almost full inhibition of tumor cell growth and survival. The remarkable synergy between chemotherapy drugs and Icmt inhibition in cervical cancer cells is likely due to the additional suppression of Ras and its downstream signaling pathways. We are the first to demonstrate the contribution of Icmt in tumor cells in response to chemotherapy. Our work also highlights Icmt inhibition as a sensitizing strategy for the treatment of cervical cancer or other Ras-driven tumors.

Synergistic antitumor effect of combined paclitaxel with FEN1 inhibitor in cervical cancer cells

Studies on cervical cancer are urgently required to improve clinical outcomes. As a major anticancer drug for cervical cancer, paclitaxel has been used for many years in clinical therapy but its therapeutic efficacy is limited by common obstacle from cancer cells. The enhanced DNA repair pathways of cancer cells have been proved to survive DNA damage induced by chemotherapeutic drug. Inhibitors of specific DNA repair pathway can sensitize cancer cells to the treatment of chemotherapeutic drugs. In this paper we found that the effect of paclitaxel can be significantly improved when used in combination with FEN1 inhibitor SC13, suggesting a synergistic mechanism between the two compounds. Our studies suggest that FEN1 inhibition could be a novel strategy of tumor-targeting therapy for cervical cancer. Our work also revealed that paclitaxel demonstrates stronger synergistic effect with SC13 than other common used chemical drugs such as doxorubicin, carboplatin or camptothecin on cervical cancer cells.

Safety and Efficacy of Pembrolizumab in Advanced, Programmed Death Ligand 1–Positive Cervical Cancer: Results From the Phase Ib KEYNOTE-028 Trial

Purpose

The KEYNOTE-028 trial ( ClinicalTrials.gov identifier: NCT02054806) was designed to assess the safety and efficacy of pembrolizumab in 20 programmed death ligand 1–positive, advanced solid tumor cohorts. Here, we present the results from the cohort of patients with advanced cervical cancer.

Methods

Patients were treated with pembrolizumab 10 mg/kg every 2 weeks for up to 24 months. Response was assessed every 8 weeks for the first 6 months and every 12 weeks thereafter. The primary end point was overall response rate per Response Evaluation Criteria in Solid Tumors, version 1.1, by investigator review. Safety was a secondary end point.

Results

Twenty-four patients were enrolled in the cervical cancer cohort. The median age was 42 years (range, 26 to 62 years), 22 patients (92%) had received prior radiation therapy, and 15 patients (63%) had received two or more lines of therapy, including bevacizumab (10 of 24 patients), for advanced disease. At the data cutoff, median follow-up duration was 11.0 months (range, 1.3 to 32.2 months). Overall response rate was 17% (95% CI, 5% to 37%); four patients (17%) achieved a confirmed partial response, and three patients (13%) had stable disease. Median duration of response for the four patients who achieved a partial response was 5.4 months (4.1 to 7.5 months). Treatment related adverse events (AEs) were experienced by 18 patients (75%); only rash (n = 5; 21%) and pyrexia (n = 4; 17%) and occurred in ≥ 10% of patients. Five patients experienced grade 3 treatment-related AEs. No grade 4 treatment-related AEs or deaths were observed.

Conclusion

In patients with programmed death ligand 1–positive advanced cervical cancer, pembrolizumab demonstrated antitumor activity and exhibited a safety profile consistent with that seen in other tumor types.

Augmented expression of cardiac ankyrin repeat protein is induced by pemetrexed and a possible marker for the pemetrexed resistance in mesothelioma cells

Background

Pemetrexed (PEM) is an anti-cancer agent targeting DNA and RNA synthesis, and clinically in use for mesothelioma and non-small cell lung carcinoma. A mechanism of resistance to PEM is associated with elevated activities of several enzymes involved in nucleic acid metabolism.

Methods

We established two kinds of PEM-resistant mesothelioma cells which did not show any increase of the relevant enzyme activities. We screened genes enhanced in the PEM-resistant cells with a microarray analysis and confirmed the expression levels with Western blot analysis. A possible involvement of the candidates in the PEM-resistance was examined with a WST assay after knocking down the expression with si-RNA. We also analyzed a mechanism of the up-regulated expression with agents influencing AMP-activated protein kinase (AMPK) and p53.

Results

We found that expression of cardiac ankyrin repeat protein (CARP) was elevated in the PEM-resistant cells with a microarray and Western blot analysis. Down-regulation of CARP expression with si-RNA did not however influence the PEM resistance. Parent and PEM-resistant cells treated with PEM increased expression of CARP, AMPK, p53 and histone H2AX. The CARP up-regulation was however irrelevant to the p53 genotypes and not induced by an AMPK activator. Augmented p53 levels with nutlin-3a, an inhibitor for p53 degradation, and DNA damages were not always associated with the enhanced CARP expression.

Conclusions

These data collectively suggest that up-regulated CARP expression is a potential marker for development of PEM-resistance in mesothelioma and that the PEM-mediated enhanced expression is not directly linked with immediate cellular responses to PEM.

Electronic supplementary material

The online version of this article (10.1186/s12935-017-0493-8) contains supplementary material, which is available to authorized users.

AJUBA increases the cisplatin resistance through hippo pathway in cervical cancer

Though LIM-domain protein AJUBA was identified as a putative oncogene, the function and underlying mechanisms of AJUBA in cervical cancer remain largely unknown. Firstly, AJUBA expression was detected via real-time quantitative PCR in patients' samples. Furthermore, Hela and Siha cells were transfected with AJUBA-overexpressing plasmids, and then exposed to cisplatin, the apoptosis was measured by cytometry assay. In addition, the expression of YAP and TAZ was disclosed through western blot assay. Our results revealed that AJUBA expression was significantly higher in the cervical cancer patients resistant to cisplatin treatment compared with cervical cancer patients sensitive to cisplatin treatment. In addition, overall survival time was significantly shorter in the cervical cancer patients with high AJUBA expression compare with those with low AJUBA expression using kaplan-meier analysis. Hela and Siha cells transfected with AJUBA-expressing plasmids exposed to cisplatin treatment had higher survival rate compared with the cells transfected with empty vector control. Mechanistic studies revealed the AJUBA upregulated the downstream targets YAP and TAZ. These results suggest that high AJUBA level enhances cervical cancer cells drug resistance to cisplatin, also associates with decreased patient survival times.

Predictive role of galectin-1 and integrin α5β1 in cisplatin-based neoadjuvant chemotherapy of bulky squamous cervical cancer

Although galectin-1 and integrin α5β1 confer chemoresistance to certain types of cancer, whether their expression predicts the response to cisplatin-based neoadjuvant chemotherapy (NACT) in squamous cervical cancer remains unclear. Paired tumor samples (pre- and post-chemotherapy) were obtained from 35 bulky squamous cervical cancer patients treated with cisplatin-based NACT and radical hysterectomy at our hospital between January 2007 and August 2014. The expression of galectin-1 and integrin α5β1 in tumor cells and stromal cells was analyzed by immunohistochemistry. The correlation between galectin-1/integrin α5β1 and apoptosis-associated markers was investigated by using the The Cancer Genome Atlas (TCGA) RNA-sequencing data. Seventeen patients were identified as chemotherapy responders and 18 as non-responders. Galectin-1 and integrin α5β1-positive immunostaining was more frequently observed in stromal cells than its in tumor cells. The expression of galectin-1 and integrin α5β1 in stromal and tumor cells was significantly down-regulated in postchemotherapy cervical cancer tissues. High levels of galectin-1 and integrin α5β1 in stromal were associated with a negative chemotherapy response in squamous cervical cancer patients treated with cisplatin-based NACT. Additionally, the expression of galectin-1 and integrin α5 correlated negatively with caspase 3/caspase 8 by using the TCGA RNA-sequencing data. Galectin-1 and integrin α5β1 expression in stromal may serve as a prediction of the responses to cisplatin-based NACT for patients with bulky squamous cervical cancer. Galectin-1 and integrin α5β1 may be implicated in the development of chemoresistance in cervical cancer via suppressing apoptosis.

Relationship between clinical toxicities and ERCC1 rs3212986 and XRCC3 rs861539 polymorphisms in cervical cancer patients

BACKGROUND

Several studies have suggested that there are single nucleotide polymorphisms (SNPs) that can be considered potential biomarkers in the prognosis and therapeutic response of cancer patients. The present study investigated the association between ERCC1 rs3212986 and XRCC3 rs861539 polymorphisms and clinical toxicities induced by chemoradiotherapy (CRT) in cervical cancer.

METHODS

This hospital-based retrospective cohort study included 260 patients with cervical cancer, FIGO stages Ib2-IVa, who underwent CRT (cisplatin). Genetic polymorphisms analysis was performed by allelic discrimination with real-time polymerase chain reaction (RT-PCR).

RESULTS

Our results indicated a link between ERCC1 rs3212986 and the onset of late gastrointestinal toxicity (p = 0.038). Furthermore, using a recessive model (AA vs. CC/CA), we found that patients carrying AA homozygous genotype presented a fourfold increased risk of developing late gastrointestinal toxicity when compared with patients with the C allele (odds ratio = 3.727, 95% confidence interval, 1.199-11.588; p = 0.017). No association was found regarding the XRCC3 rs861539 polymorphism and any clinical toxicity event.

CONCLUSIONS

This is the first study evaluating the relationship between these polymorphisms and clinical toxicities in cervical cancer patients submitted to CRT with cisplatin. These results may contribute toward a better understanding of the influence of genetic polymorphisms in genes associated with DNA repair in the clinical response to CRT of patients with cervical cancer.

Cisplatin regulates cell autophagy in endometrial cancer cells via the PI3K/AKT/mTOR signalling pathway

Endometrial cancer is the most common gynaecological malignancy encountered in developed countries and the second most common in the developing world. The five-year survival rate of patients with endometrial cancer diagnosed at a late stage is <30%. Therefore, it is critical to develop a suitable chemotherapeutic regimen for late-stage endometrial cancer. Cisplatin (CDDP) is a first-line chemotherapeutic drug for endometrial cancer chemotherapy. The present study investigated the molecular mechanism underlying the effect of CDDP on endometrial cancer from the perspective of cell autophagy. Ishikawa cells were treated with 10, 20, 40 or 80 µg/ml CDDP for 12, 24, 48 and 72 h. The cells were then harvested and subjected to cell proliferation assays. Based on the results, 20 µg/ml CDDP was selected as the treatment used for 12 and 24 h for the assays. To detect the effect of CDDP on Ishikawa cell autophagy, autophagosome formation was observed using a transmission electron microscope, and the expression level of autophagy-related gene microtubule-associated protein 1 light chain 3α, was examined using immunofluorescence microscopy. The results demonstrated that CDDP treatment promoted cell autophagy in Ishikawa cells. In addition, the total and phosphorylated protein levels of phosphoinositide 3-kinase (PI3K) p85, protein kinase B (AKT) and mammalian target of rapamycin (mTOR), the key proteins of the PI3K/AKT/mTOR signalling pathway, were detected by western blot analysis. The results indicated that CDDP treatment inactivated the PI3K/AKT/mTOR signalling pathway. To further examine whether CDDP affects cell autophagy in Ishikawa cells via the PI3K/AKT/mTOR signalling pathway, the cells were co-treated with a PI3K activator, insulin-like growth factor-1 (IGF-1). The results demonstrated that IGF-1 co-treatment reversed the effect of CDDP on cell autophagy in Ishikawa cells. In brief, the present study hypothesized that CDDP may regulate cell autophagy in the Ishikawa endometrial cancer cell line via the PI3K/AKT/mTOR signalling pathway.

Targeting the eIF4E/β-catenin axis sensitizes cervical carcinoma squamous cells to chemotherapy

Chemotherapy has improved the clinical outcomes of cervical cancer patients. However, patients develop chemoresistance, whose underlying mechanisms are not well understood. In this study, we investigated the phosphorylation levels of eukaryotic translation initiation factor 4E (eIF4E) in cervical cancer cells subjected to chemotherapy. Results showed that chemotherapeutic drugs significantly increased eIF4E phosphorylation at S209 in HeLa and SiHa cells. Upregulation of phosphorylated eIF4E (p-eIF4E) levels has also been shown in cisplatin-resistant HeLa cells and has been observed to be a common response of cervical cancer patients undergoing chemotherapy. We further showed that chemotherapeutic drugs increase β-catenin activity and mRNA levels of Wnt/β-catenin target genes in cervical cancer cells but not in eIF4E-depleted cells, suggesting that chemotherapeutic drugs activate Wnt/β-catenin signaling in an eIF4E-dependent manner. Inhibiting eIF4E via siRNA knockdown or Wnt/β-catenin using the Wnt inhibitor pyrvinium effectively enhanced the anti-proliferative and pro-apoptotic effects of cisplatin in cervical cancer cells both in vitro and in vivo. Our findings demonstrate that eIF4E/β-catenin signaling plays a positive regulatory role in the resistance of cervical cancer cell to chemotherapy and thus highlight the therapeutic value of eIF4E or β-catenin inhibition in overcoming chemoresistance.