Chemotherapy for recurrent or metastatic squamous cell carcinoma of the head and neck

Functional role of miR-148a in oropharyngeal cancer: influence on pregnane X receptor and P-glycoprotein expression

MicroRNAs are short noncoding RNAs of about 19-25 nucleotides that usually target the 3' untranslated regions of mRNAs thus mediating post-transcriptional regulation of gene expression. Previous data indicate a role for miR-148a in the regulation of the pregnane X receptor (PXR/NR1I2), a nuclear receptor that regulates the expression of drug transporters like P-glycoprotein (P-gp/ABCB1). Our study investigated the effect of miR-148a on the post-transcriptional regulation of PXR and its target gene ABCB1 in oropharyngeal cancer cell lines (OPSCC). miR-148a was over-expressed and knocked-down in three OPSCC cell lines (HNO41, HNO206, and HNO413) by transfection with miR-148a mimic and miR-148a antagomir, respectively. Expression of miR-148a, NR1I2, and ABCB1 mRNA was quantified via real-time qPCR, protein expression of PXR was assessed by immunoblotting. Transfection of miR-148a mimic led to increased miR-148a levels in all cell lines and transfection of miR-148a antagomir reduced miR-148a expression in HNO206 and HNO413. Whereas these changes had no significant effect on PXR mRNA expression, protein expression was reduced in HNO41 by transfection with miR-148a and increased in HNO413 by transfection with miR-148a antagomir. Transfection of miR-148a downregulated ABCB1 mRNA in all cell lines, whereas antagonizing miR-148a had no significant effect. Our data demonstrate a modulation of PXR/NR1I2 and ABCB1 expression in OPSCC by miR-148a, however the effect was not uniform in all cell lines and depended on the range of expression of miR-148 and the genotype of rs1054190 SNP in NR1I2 3'UTR. Thus, our findings argue against an unequivocal association between miR-148a and PXR levels in OPSCC.

Multi-kinase inhibitors and cisplatin for head and neck cancer treatment in vitro

Multidrug resistance (MDR) remains one of the major causes of suboptimal outcome following therapy in head and neck squamous cell carcinoma (HNSCC). ATP-binding cassette (ABC) transporters are overexpressed in HNSCC, which contributes to the limited effect of chemotherapeutic treatment. In addition to their named function, tyrosine kinase inhibitors (TKIs) have been revealed to impact on ABC transporter activity and expression. Therefore, the present study aimed to investigate the effects of combination therapy using different TKIs combined with cisplatin. Reverse transcription-quantitative PCR was used to characterize ABC transporter and receptor expression in 5 HNSCC cell lines treated with 3 different TKIs (pazopanib, dovitinib, nintedanib) and cisplatin. Treatment efficacy was analyzed using a crystal violet staining assay. Analysis of ABC transporter (ABCB1, ABCC1 and ABCG2) genetic alterations was performed using The Cancer Genome Atlas. Statistical analysis was conducted to evaluate the effects of mono- and combination treatment. With the exception of ABCB1, all of the investigated ABC transporters were expressed in each cell line. The additive effects of TKI + cisplatin combination treatment were observed for pazopanib in three cell lines, nintedanib in four cell lines, and were not observed for dovitinib in any of the cell lines investigated. The combination of multi-kinase inhibitors and conventional chemotherapy in HNSCC may strengthen the use of current therapeutic strategies; nintedanib appears to be the most suitable TKI for combination therapy. Further efforts are required to classify TKI efficacy with regard to cisplatin resistance.

Niclosamide Induces Cell Cycle Arrest in G1 Phase in Head and Neck Squamous Cell Carcinoma Through Let-7d/CDC34 Axis

Niclosamide is a traditional anti-tapeworm drug that exhibits potent anti-cancer activity. Our previous study showed that niclosamide induces cell cycle arrest in G1 phase. Nevertheless, the underlying mechanism remains unknown. The following study investigated the molecular mechanism through which niclosamide induced G1 arrest in head and neck squamous cell carcinoma (HNSCC) cell lines. The effect of niclosamide on human HNSCC cell line WSU-HN6 and CNE-2Z were analyzed using IncuCyte ZOOM^TM assay, flow cytometry (FCM), real-time PCR and western blot. Luciferase assay was conducted to demonstrate the interaction between let-7d (a let-7 family member which functions as a tumor suppressor by regulating cell cycle) and 3′UTR of CDC34 mRNA. Xenografts tumor model was established to evaluate the niclosamide treatment efficacy in vivo. Briefly, an exposure to niclosamide treatment led to an increased let-7d expression and a decreased expression of cell cycle regulator CDC34, finally leading to G1 phase arrest. Moreover, an overexpression of let-7d induced G1 phase arrest and downregulated CDC34, while the knockdown of let-7d partially rescued the niclosamide-induced G1 phase arrest. Luciferase assay confirmed the direct inhibition of CDC34 through the targeting of let-7d. Furthermore, niclosamide markedly inhibited the xenografts growth through up-regulation of let-7d and down-regulation of CDC34. To sum up, our findings suggest that niclosamide induces cell cycle arrest in G1 phase in HNSCC through let-7d/CDC34 axis, which enriches the anti-cancer mechanism of niclosamide.

Histone Methyltransferase G9a Drives Chemotherapy Resistance by Regulating the Glutamate-Cysteine Ligase Catalytic Subunit in Head and Neck Squamous Cell Carcinoma

Transient chemotherapeutic response is a major obstacle to treating head and neck squamous cell carcinomas (HNSCC). Histone methyltransferase G9a has recently been shown to be abundantly expressed in HNSCC, and is required to maintain the malignant phenotype. In this study, we found that high G9a expression is significantly associated with poor chemotherapeutic response and disease-free survival in HNSCC patients. Similarly, G9a expression and enzymatic activity were elevated in cisplatin-resistant HNSCC cells. Genetic or pharmacologic inhibition of G9a sensitized the resistant cells to cisplatin, increasing cellular apoptosis. Mechanistic investigations indicated that G9a contributes to transcriptional activation of the glutamate-cysteine ligase catalytic subunit (GCLC), which results in upregulation of cellular glutathione (GSH) and drug resistance. In addition, we observed a significant positive correlation between G9a and GCLC expression in tumors of HNSCC patients. Taken together, our findings provide evidence that G9a protects HNSCC cells against chemotherapy by increasing the synthesis of GSH, and imply G9a as a promising target for overcoming cisplatin resistance in HNSCC. Mol Cancer Ther; 16(7); 1421-34. ©2017 AACR.

Temporal changes in the efficacy of chemotherapy for recurrent or metastatic squamous cell carcinoma of the head and neck: a systematic review and meta-analysis

BACKGROUND

Cytotoxic chemotherapy remains a standard treatment option for patients with recurrent or metastatic squamous cell carcinoma of the head and neck (RMSCCHN), but its effectiveness is debatable. We hypothesized palliative chemotherapy efficacy has decreased due to intensification of primary treatment, and investigated this by examining time trends of objective response rates (ORRs) in published reports of randomized trials (RCTs).

METHODS

RCTs with at least one arm studying chemotherapy alone in RMSCCHN patients and reporting ORR were identified and data extracted. Eligible regimens had at least 6 trial arms reporting ORR over 20 years. Weighted linear regressions of ORR by year of publication for eligible regimens were done, and predictors of ORR and survival were examined.

RESULTS

Three regimens were eligible for analysis: low dose methotrexate, single agent cisplatin, and cisplatin plus infusional 5-fluorouracil (PF). Linear regression showed decreasing ORRs over time for all three regimens studied: 23.5 to 9.8% (1980-2010) for methotrexate (p=0.06), 19.6 to 8.8% (1980-2010) for cisplatin (p=0.0013), and 37.6 to 27.9% (1990-2010) for PF (p=0.11). Trial sample size, oropharynx cancer primary site, use of PF, and prior treatment increased over time. Use of PF and year of publication were the strongest predictors of ORR.

CONCLUSIONS

These data confirm the limited effectiveness of currently available palliative chemotherapy regimens for RMSCCHN patients. Novel therapeutics offering improvements in quality and quantity of life are urgently needed for these patients. Based on these results, the study of such agents as first-line therapy in RMSCCHN patients is entirely justifiable.

Antiproliferative efficacies but minor drug transporter inducing effects of paclitaxel, cisplatin, or 5-fluorouracil in a murine xenograft model for head and neck squamous cell carcinoma

Drug-induced multidrug resistance (MDR) has been linked to overexpression of drug transporting proteins in head and neck squamous cell carcinoma (HNSCC) in vitro. The aim of this work was to reassess these findings in a murine xenograft model. NOD-SCID mice xenotransplanted with 10 (6) HNO97 cells were treated for four consecutive weeks with weekly paclitaxel, biweekly cisplatin (both intraperitoneal), or 5-fluorouracil (5-FU, administered by osmotic pump). Tumor volume and body weight were weekly documented. Expression of drug transporters and Ki-67 marker were examined using quantitative real-time polymerase chain reaction and/or immunohistochemistry. Both paclitaxel and cisplatin significantly reduced tumor volumes after 2-3 weeks. 5-FU-treated animals had significantly lower body weights after 2 or 4 weeks of chemotherapy. None of the drugs affected expression of drug transporters at the mRNA level. However, P-glycoprotein (Pgp) protein expression was increased by paclitaxel (P<0.01). Ki-67 expression did not change during treatment irrespective of the drug applied. Paclitaxel and cisplatin are effectively tumor volume reducing drugs in a murine xenograft model of HNSCC. Paclitaxel enhanced Pgp expression at the protein level, but not at the mRNA level suggesting transcriptional induction to be of minor relevance. In contrast, posttranscriptional mechanisms or Darwinian selection of intrinsically drug transporter overexpressing MDR cells might lead to iatrogenic chemotherapy resistance in HNSCC.

Methotrexate Revisited—in Recurrent Head and Neck Cancer

Aims

Response of single agent chemotherapy in improving quality of life in patients with recurrent head and neck cancers.

Methods and material

This is a study of the 18 patients with advanced cancers of head and neck, who had failed earlier attempts of radical treatment with Surgery, Radiotherapy ± chemotherapy and have residual or recurrent tumours, were treated with single agent Injection Methotrexate 50 mg/m2 weekly. Follow up visit complaints and clinical examination details were recorded. History regarding pain, speech and diet was collected for every visit. Severity of pain was divided with the National Cancer Institute's Common Terminology Criteria for Adverse Events (CTCAE) version 3.0 pain scales. Symptom control was done with analgesics, antiemetic and infection control.

Results

Weekly single agent chemotherapy with injection Methotrexate has significantly improved the quality of life of patients. 38.8% of patients have shown good response with decrease in the tumour bulk by more than 50% and other 39% of patients have stable disease on Injection Methotrexate. 22.2% patients have shown disease progression on single agent chemotherapy. Overall 83.3% patients have shown improvement in Quality of life in terms of symptomatic control. After 6 weekly treatments with injection methotrexate 63% patients were pain free with 16% patients reported decrease in pain. 87.5% of patients have shown improvement in speech and diet. Improvement in symptoms has shown decrease in depression in cancer patients. Grade 3 toxicity observed was Neutropenia (11.1%), anaemia (11.1%) and Mucositis (16.6%) which was managed adequately. Median survival with good quality of life is 5.4 months.

Conclusions

Single agent methotrexate chemotherapy on an out-patient basis can provide good quality of life. Decrease in pain along with improvement in speech and diet has shown decrease in incidence of depression and overall positive impact on psychosocial status. Few cases have shown sustained regression of gross disease adding to maintained quality of life with better socio-economic compliance.

Regulation of excision repair cross-complementation group 1 by Snail contributes to cisplatin resistance in head and neck cancer

PURPOSE

We investigated the mechanism and clinical significance of the epithelial-mesenchymal transition (EMT)-induced chemoresistance in head and neck squamous cell carcinoma (HNSCC).

EXPERIMENTAL DESIGN

The correlation between the expression of different EMT regulators and chemoresistance genes, such as excision repair cross complementation group 1 (ERCC1), was evaluated in cancer cell lines from the NCI-60 database and four human HNSCC cell lines. Ectopic expression of Snail or short-interference RNA-mediated repression of Snail or ERCC1 was done in HNSCC cell lines. Cell viability was examined for cells after cisplatin treatment. A luciferase reporter assay and chromatin immunoprecipitation were used to identify the transcriptional regulation of ERCC1 by Snail. Immunohistochemical analysis of Snail, Twist1, ERCC1, hypoxia inducible factor-1 α (HIF-1α), and NBS1 were done in samples from 72 HNSCC patients receiving cisplatin-based chemotherapy.

RESULTS

The correlation between the expression of Snail and ERCC1 was confirmed in different cell lines, including HNSCC cells. In HNSCC cell lines, overexpression of Snail in the low endogenous Snail/ERCC1 cell lines FaDu or CAL-27 increased ERCC1 expression, and hypoxia or overexpression of NBS1 also upregulated ERCC1. Knockdown of Snail in the high endogenous Snail/ERCC1 cell line OECM-1 downregulated ERCC1 expression and attenuated cisplatin resistance. Furthermore, suppression of ERCC1 in Snail- or NBS1-overexpressing HNSCC cells enhanced sensitivity to cisplatin. Snail directly regulated ERCC1 transcription. In patients with HNSCC, coexpression of Snail and ERCC1 correlated with cisplatin resistance and a poor prognosis.

CONCLUSIONS

Activation of ERCC1 by Snail is critical in the generation of cisplatin resistance of HNSCC cells.

Alterations in the p53 pathway and their association with radio- and chemosensitivity in head and neck squamous cell carcinoma

Chemotherapy and/or radiotherapy are established measures in treatment protocols of head and neck squamous cell carcinoma (HNSCC). However, we still lack reliable predictive markers for the response to radio- and chemotherapy. The p53 pathway is involved in stress response and thus might influence chemo-/radiosensitivity. Using 29 HNSCC cell lines previously characterized for p53 mutations, we simultaneously analyzed several key players in the p53 pathway by RT-PCR, transcript sequencing and immunohistochemistry, and investigated their association with chemosensitivity and radiosensitivity. Cell lines with p53 mutations were slightly more sensitive to cisplatin than those with wild-type p53. The type of mutation did not influence radio- or chemosensitivity. p14(ARF), an activator of p53, was lost or mutated in all cell lines. Three cell lines showed overexpression of HDM-2, a major negative regulator of p53; however, HDM-2 levels did not correlate with radio- or chemosensitivity. HPV-16 oncoproteins were detected in one highly chemoresistant cell line. Our findings suggest that molecular events resulting in the inactivation of the p53 pathway occur in all HNSCC cell lines. However, single alterations in the p53 pathway are not reliable predictors for the response to radio- or chemotherapy in HNSCC.

Valproic acid as a therapeutic agent for head and neck squamous cell carcinomas

PURPOSES

Here we investigate if valproic acid (VA) can enhance the efficacy of commonly used therapies for head and neck squamous cell carcinomas (HNSCC) and the molecular mechanisms that may be related to its anticancer effects.

METHODS

Proliferation and viability of distinct cell types subjected to VA treatment alone or in combination regimens were measured through BrdU incorporation and LDH release, respectively. Molecular markers compatible with histone deacetylase inhibitory activity of VA were assessed through western blots assays in lysates obtained from cultured cells and tumour biopsies.

RESULTS

Treatment of all cell types with VA resulted in a dose-dependent increase in histone H3 acetylation and p21 expression, as well as dose-dependent cytostasis. In contrast, the cytotoxic response to VA was variable and did not correlate with cytostasis, histone acetylation or p21 induction. The variability in response to VA was also observed in tumour biopsy samples collected from patients prior to and following a 1 week oral course of VA. In addition, we found that a combination of a clinically achievable concentration of VA plus cisplatin caused a threefold to sevenfold increase in cisplatin cytotoxicity in vitro.

CONCLUSIONS

VA acts as a histone deacetylase inhibitor (HDI) in SCC cells and normal human keratinocytes (HKs), potentiates the cytotoxic effect of cisplatin in SCC cell lines and decreases the viability of SCC cells as opposed to HKs. Taken together, the results provide initial evidence that VA might be a valuable drug in the development of better therapeutic regimens for HNSCC.

A phase Ib and pharmacokinetic trial of patupilone combined with carboplatin in patients with advanced cancer

PURPOSE

Patupilone is a microtubule-targeting chemotherapeutic agent with clinical activity in a broad range of taxane-sensitive/resistant tumor types. The present phase Ib study examined the safety/tolerability and pharmacokinetics of patupilone in combination with carboplatin in patients with advanced solid tumors.

EXPERIMENTAL DESIGN

Patients with advanced cancer received patupilone via a 5- to 10-min i.v. infusion at doses of 3.6 to 6.0 mg/m(2) q3w, immediately followed by carboplatin area under the curve (AUC) 5 or 6 mg/mL/min.

RESULTS

Of the 37 patients enrolled, the majority previously received taxanes (81%) and/or platinum-containing drugs (97.3%). The maximum tolerated dose (MTD) of patupilone with carboplatin AUC 6 was 4.8 mg/m(2); additional patients were enrolled to consolidate experience at this dose. Of the 22 patients who received the MTD, the most common nonhematologic adverse events were fatigue in six (27.3%) and diarrhea, nausea, vomiting, abdominal pain, and neuropathy in one each (4.5%; all grade 3); hematologic toxicities included two patients (9.1%) with grade 3 neutropenia. The pharmacokinetics of patupilone were similar to those in a previous study of patupilone monotherapy. Of the 26 patients with recurrent platinum-sensitive ovarian cancer, tumor response was assessable by response evaluation criteria in solid tumors in 17; 1 patient (6%) achieved a complete response, and 10 (59%) achieved a partial response.

CONCLUSIONS

The combination of patupilone 4.8 mg/m(2)/carboplatin AUC 6 was well tolerated and showed antitumor activity similar to established regimens in patients with recurrent platinum-sensitive ovarian cancer. The optimal dose for this regimen is currently being further refined in phase II trials.

Überleben mit hämatogen metastasierten HNO-Tumoren

QUESTIONS

The objective of this retrospective analysis was to investigate parameters with a potential impact on survival in a collective of 114 patients with distant metastatic disease after head and neck cancer.

PATIENTS AND METHODS

The primary endpoint was the survival with distant metastatic disease, the secondary endpoint was overall survival. Primary therapy, local recurrence, second neoplasms, palliative chemotherapy (CHT) and radiotherapy (RT), as well as Karnofsky performance status (KPS) at the time of diagnosis of the metastases were analyzed as potential impact parameters using the log-rank test with subsequent Cox regression analysis.

RESULTS

Palliative CHT (P=0.0020) and KPS (P=0.0011) had a significant positive impact on the median survival probability with metastases (8.2 months) using the log-rank test, KPS at the time of diagnosis of metastases remained as an independent prognostic parameter in the Cox regression (P=0.0013). Primary therapy, local tumor control and KPS had a significant positive influence on the median overall survival probability (18.5 months) univariately (P=0.0139, P=0.0106, P= 0.0096) and multivariately (P=0.0123, and P=0.0063, P=0.0197, respectively).

CONCLUSIONS

KPS at the time of diagnosis of metastases is an independent prognostic parameter for both endpoints. Lacking evidence for life prolongation, palliative therapies should therefore first and foremost focus on the stabilization of the KPS.

Pemetrexed: a multitargeted antifolate

BACKGROUND

The US Food and Drug Administration approved pemetrexed in February 2004 for the treatment of malignant pleural mesothelioma (MPM) in combination with cisplatin in patients with unresectable disease or for whom curative surgery is not an option. Pemetrexed is the first agent approved for the treatment of MPM. In August 2004, pemetrexed was approved as a second-line, single-agent treatment of locally advanced or metastatic non-small cell lung cancer (NSCLC).

OBJECTIVES

The goals of this article were to summarize the pharmacology, pharmacokinetics, efficacy, and safety of pemetrexed, and to review its current and potential roles in therapy for MPM, NSCLC, and other oncologic conditions.

METHODS

Relevant English-language literature was identified through searches of PubMed (1966-December 2004), International Pharmaceutical Abstracts, and the Proceedings of the American Society of Clinical Oncology (January 1995-December 2004). Search terms included pemetrexed, Alimta, MTA, multitargeted antifolate, LY231514, mesothelioma, MPM, non-small cell lung cancer, NSCLC, breast cancer, and pancreatic cancer. In addition to published literature, abstracts and posters presented at national and international scientific meetings were reviewed.

RESULTS

Myelosuppression was the predominant dose-limiting toxicity of pemetrexed reported in Phase I studies. Identification of the correlation between poor folate status and increased pemetrexed toxicity in a multivariate analysis led to the requirement of folic acid and vitamin B12 supplementation for patients in all pemetrexed studies, with a resulting noted decrease in pemetrexed toxicity. A single, multicenter, randomized Phase III trial compared the efficacy of pemetrexed in combination with cisplatin versus cisplatin alone in the treatment of MPM. Response rates were 41.3% in the pemetrexed/cisplatin combination and 16.7% with single-agent cisplatin (P < 0.001). The median survival time for the pemetrexed/cisplatin combination was significantly longer at 12.1 months versus 9.3 months for cisplatin alone (P = 0.02). One international, multicenter, randomized Phase III trial in patients with NSCLC compared single-agent pemetrexed versus docetaxel in patients previously treated with chemotherapy. Overall response rates (9.1% and 8.8%) and median survival (8.3 months and 7.9 months) did not differ between pemetrexed and docetaxel (P = 0.105 and P = 0.226, respectively). Hematologic adverse effects-grade 3/4 neutropenia (40.2% vs 5.3%; P < 0.001), febrile neutropenia (12.7% vs 1.9%; P < 0.001), and neutropenic infections (3.3% vs 0%; P = 0.004)-were significantly greater in the docetaxel-treated patients than in the pemetrexed-treated patients, as was alopecia (37.7% vs 6.4%; P < 0.001). Results of an international, multicenter Phase III trial of pemetrexed in combination with gemcitabine conducted in patients with pancreatic cancer indicate that the combination is no more efficacious than single-agent gemcitabine. Results in other disease states are still preliminary.

CONCLUSIONS

Pemetrexed is a multitargeted antifolate that has demonstrated antitumor activity in various tumor types as a single agent and in combination with other chemotherapeutic agents. Efficacy for the treatment of MPM in combination with cisplatin has been demonstrated, and approval as a second-line agent in NSCLC was based on response rate as a surrogate end point for survival. The addition of folic acid and vitamin B12 supplementation markedly reduced.

A Phase II study of SU5416 in patients with advanced or recurrent head and neck cancers

BACKGROUND

SU5416 (semaxanib) is a synthetic small molecule inhibitor of the tyrosine kinase domain of vascular endothelial growth factor receptor 2 (VEGFR2). This Phase II study was conducted to determine the safety and efficacy of SU5416 in patients with recurrent or metastatic head and neck cancers.

PATIENTS AND METHODS

This was an open label, single arm, Phase 2 study for patients who had received no more than 2 cytotoxic regimens. Thirty-five patients received intravenous SU5416 (145 mg/m(2)) twice per week by intravenous catheter. Radiologic imaging for response assessment was planned at the conclusion of each 8 week cycle. Serum VEGF levels and power Doppler ultrasound tumor imaging were explored as potential surrogate markers for SU5416 activity.

RESULTS

Thirty-two patients had received prior radiotherapy, including 18 patients who received prior concurrent chemoradiotherapy. Twelve patients had received prior chemotherapy in the recurrent disease setting. Thirty-one patients were evaluable for response. There was one partial response and one minor response. The median number of 8-week cycles received was 1 (range 1-4). Median overall survival was 6.25 months. The most common > or = grade 3 toxicity was headache (31%). There was one fatal carotid artery hemorrhage. Fatigue, nausea, and vomiting were common grade 1-2 adverse events. Power Doppler ultrasound demonstrated decreased tumor vascularity in 5 of 7 patients.

CONCLUSIONS

Treatment with SU5416 in patients with head and neck cancers is feasible, but objective responses are rare. Studies evaluating more potent anti-angiogenic agents in this disease are of interest.

New and emerging radiosensitizers and radioprotectors

The combination of chemotherapy and radiation has led to clinical breakthroughs in several disease sites, and current work continues to define optimum combinations of proven chemotherapy as well as more recently available, noncytotoxic agents. Administration of systemic therapies allows modulation of radiation response to improve tumor control (radiosensitization) or to prevent normal tissue toxicity (radioprotection). Substantial progress has been made in identifying the targets of standard chemotherapeutic radiation sensitizers and protectors as well as in the introduction of a new generation of molecularly targeted therapies in combination with radiation. We have reviewed the most recent, predominantly early phase clinical trials combining systemic agents with radiation. Although the proof of an improved schedule ultimately needs to come from well-run Phase III trials, the search among schedules could be shortened by the use of surrogate endpoints such as presence of active drug metabolites in the tumor. This has been accomplished only in a few cases and needs to become a more standard part of radiation sensitizer and protector trials.

Satraplatin: an orally available platinum analog for the treatment of cancer

Satraplatin is a novel, orally bioavailable, platinum anticancer drug. Platinum analogs form the mainstay of treatment for a number of cancers, including lung, ovarian, colorectal and head and neck cancer. A disadvantage of the currently marketed platinum analogs is that they must all be administered via intravenous infusion. In addition, their utility is often limited by toxicity, particularly neurotoxicity, ototoxicity and renal toxicity. Satraplatin has preclinical antitumor activity comparable with that of cisplatin and, clinically, has a more manageable side-effect profile. Satraplatin is active in lung, ovarian and prostate cancer, and appears to have good efficacy in combination with radiation for lung and head and neck cancer. Preclinical data suggest it may also be effective for the treatment of certain cisplatin-refractory tumors. A large, randomized Phase III trial is currently evaluating satraplatin in combination with prednisone for the treatment of patients with hormone-refractory prostate cancer whose disease has progressed following prior systemic therapy. Positive results from this trial would support regulatory approval for satraplatin for this indication. The availability of an active oral platinum agent, such as satraplatin, with few of the serious toxicities associated with traditional intravenous platinum compounds makes satraplatin an alternative to other platinum agents and a new treatment option in the oncologist's armamentarium.

Targeting signal transducer and activator of transcription 3 with G-quartet oligonucleotides: a potential novel therapy for head and neck cancer

Signal transducer and activator of transcription 3 (Stat3) is a critical mediator of oncogenic signaling activated frequently in many types of human cancer where it contributes to tumor cell growth and resistance to apoptosis. Stat3 has been proposed as a promising target for anticancer drug discovery. Recently, we developed a series of G-quartet oligodeoxynucleotides (GQ-ODN) as novel and potent Stat3 inhibitors, which significantly suppressed the growth of prostate and breast tumors in nude mice. In the present study, we showed that GQ-ODN specifically inhibited DNA-binding activity of Stat3 as opposed to Stat1. Computer-based docking analysis revealed that GQ-ODN predominantly interacts with the SH2 domains of Stat3 homodimers to destabilize dimer formation and disrupt DNA-binding activity. We employed five regimens in the treatment of nude mice with tumors of head and neck squamous cell carcinoma (HNSCC): placebo, paclitaxel, GQ-ODN T40214, GQ-ODN T40231, and T40214 plus paclitaxel. The mean size of HNSCC tumors over 21 days only increased by 1.7-fold in T40214-treated mice and actually decreased by 35% in T40214 plus paclitaxel-treated mice whereas the mean size of HNSCC tumors increased 9.4-fold in placebo-treated mice in the same period. These findings show that GQ-ODN has potent activity against HNSCC tumor xenografts alone and in combination with paclitaxel.

Reduced Cisplatin Sensitivity of Head and Neck Squamous Cell Carcinoma Cell Lines Correlates with Mutations Affecting the COOH-Terminal Nuclear Localization Signal of p53

PURPOSE

Head and neck squamous cell carcinomas (HNSCC) are the most frequent malignancies of the upper aerodigestive tract. Cisplatin resistance is a major problem in the treatment of a large number of HNSCC cancer patients. In this study, nine randomly selected HNSCC cell lines were investigated regarding expression, presence of mutations, nucleocytoplasmic distribution of p53, and sensitivity to cisplatin.

EXPERIMENTAL DESIGN

Protein expression was evaluated by Western blot analysis. The whole open reading frame of p53 was determined by reverse transcription-PCR sequencing. Nucleocytoplasmic distribution was evaluated by confocal laser scanning microscopy. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide viability assay was used to test for cisplatin sensitivity.

RESULTS

p53 mutations were found in all nine investigated HNSCC cell lines. Nuclear p53 signal was detected in six cell lines, whereas three cell lines exhibited total loss of nuclear p53 signal. Nuclear signal depended on the presence or absence of the COOH-terminal nuclear localization signal in p53. Cisplatin sensitivity was highly reduced in the group with loss of nuclear p53 signal compared with those with detectable nuclear signal. Transfection of wild-type and mutant p53 into a rat embryonic cell system showed highly reduced activity of the nuclear localization signal mutant p53 protein.

CONCLUSION

Taken together, these data suggest that "loss of nuclear p53 signal" correlates with cisplatin resistance in HNSCC. If these results can be validated on a larger number of tumor samples, including fresh tumor tissues, it potentially could help in sparing a subgroup of HNSCC patients the side effects associated with unnecessary chemotherapy by identifying cisplatin nonresponders before chemotherapy induction.