Radiosensitizers in cervical cancer. Cisplatin and beyond

Cervical cancer continues to be a significant health burden worldwide. Globally, the majority of cancers are locally advanced at diagnosis; hence, radiation remains the most frequently used therapeutical modality. Currently, the value of adding cisplatin or cisplatin-based chemotherapy to radiation for treatment of locally advanced cervical cancer is strongly supported by randomized studies and meta-analyses. Nevertheless, despite these significant achievements, therapeutic results are far from optimal; thus, novel therapies need to be assayed. A strategy currently being investigated is the use of newer radiosensitizers alone or in combination with platinum compounds. In the present work, we present preclinical information on known and newer cytotoxic agents as radiosensitizers on cervical cancer models, as well as the clinical information emanating from early phase trials that incorporate them to the cervical cancer management. In addition, we present the perspectives on the combined approach of radiation therapy and molecular target-based drugs with proven radiosensitizing capacity

Hydralazine target: From blood vessels to the epigenome

Hydralazine was one of the first orally active antihypertensive drugs developed. Currently, it is used principally to treat pregnancy-associated hypertension. Hydralazine causes two types of side effects. The first type is an extension of the pharmacologic effect of the drug and includes headache, nausea, flushing, hypotension, palpitation, tachycardia, dizziness, and salt retention. The second type of side effects is caused by immunologic reactions, of which the drug-induced lupus-like syndrome is the most common, and provides clues to underscoring hydralazine's DNA demethylating property in connection with studies demonstrating the participation of DNA methylation disorders in immune diseases. Abnormalities in DNA methylation have long been associated with cancer. Despite the fact that malignant tumors show global DNA hypomethylation, regional hypermethylation as a means to silence tumor suppressor gene expression has attracted the greatest attention. Reversibility of methylation-induced gene silencing by pharmacologic means, which in turns leads to antitumor effects in experimental and clinical scenarios, has directed efforts toward developing clinically useful demethylating agents. Among these, the most widely used comprise the nucleosides 5-azacytidine and 2'deoxy-5-azacytidine; however, these agents, like current cytotoxic chemotherapy, causes myelosuppression among other side effects that could limit exploitation of their demethylating properties. Among non-nucleoside DNA demethylating drugs currently under development, the oral drug hydralazine possess the ability to reactivate tumor suppressor gene expression, which is silenced by promoter hypermethylation in vitro and in vivo. Decades of extensive hydralazine use for hypertensive disorders that demonstrated hydralazine's clinical safety and tolerability supported its testing in a phase I trial in patients with cancer, confirming its DNA demethylating activity. Hydralazine is currently being evaluated, along with histone deacetylase inhibitors either alone or as adjuncts to chemotherapy and radiation, for hematologic and solid tumors in phase II studies

Radiation-sparing managements for cervical cancer: a developing countries perspective

Cervical cancer is the seventh most frequent cancer worldwide but more than 80% of cases occur in developing countries. Till date, radiation therapy with external beam and brachytherapy remains as the core treatment for most stages of cervical cancer. However, radiation treatment protocols and equipment modelled on the best developed countries can be seldom applied directly to developing countries owing to financial constraints and lack of qualified personnel, thus, a substantial proportion of patients do not have access to even palliative radiation therapy. Treatment options when the standard therapy is either not available or difficult to reproduce in particular settings is highly desirable with the potential to save lives that otherwise could be lost by the lack of adequate treatment. These options of treatment ideally had to have show, 1) that these are not inferior to the "standard" in terms of either survival or quality of life; 2) that these can be delivered in settings were the "standard" is not available or if available its quality is poor; and 3) that the treatment option be accepted by the population to be treated. Based on these considerations, it is obvious that cervical cancer patients, particularly those who live in countries with limited resources and therefore may not have sufficient radiation therapy resources are in need of newer therapeutical options. There is now a considerable amount of information emanating from clinical studies where surgery has a major role in treating this disease. These forms of "radiation-sparing" treatments include total mesometrial resection that could make unnecessary the use of adjuvant radiation; neoadjuvant chemotherapy that could avoid the use of adjuvant radiation in around 85% of patients and preoperative chemoradiation that could make brachytherapy dispensable. The feasibility and therapeutical value of these potential forms of management need to be prospectively evaluated

Brachytherapy versus radical hysterectomy after external beam chemoradiation: a non-randomized matched comparison in IB2-IIB cervical cancer patients

<p>Abstract</p> <p>Background</p> <p>A current paradigm in the treatment of cervical cancer with radiation therapy is that intracavitary brachytherapy is an essential component of radical treatment. This is a matched retrospective comparison of the results of treatment in patients treated with external beam chemoradiation (EBRT-CT) and radical hysterectomy versus those treated with identical chemoradiation followed by brachytherapy.</p> <p>Methods</p> <p>In this non-randomized comparison EBRT-CT protocol was the same in both groups of 40 patients. In the standard treated patients, EBRT-CT was followed by one or two intracavitary Cesium (low-dose rate) applications within 2 weeks of finishing external radiation to reach a point A dose of at least 85 Gy. In the surgically treated patients, radical hysterectomy with bilateral pelvic lymph node dissection and para-aortic lymph node sampling were performed within 7 weeks after EBRT-CT. Response, toxicity and survival were evaluated.</p> <p>Results</p> <p>A total of 80 patients were analyzed. The patients receiving EBRT-CT and surgery were matched with the standard treated cases. There were no differences in the clinicopathological characteristics between groups or in the delivery of EBRT-CT. The pattern of acute and late toxicity differed. Standard treated patients had more chronic proctitis while the surgically treated had acute complications of surgery and hydronephrosis. At a maximum follow-up of 60 months, median follow-up 26 (2–31) and 22 (3–27) months for the surgery and standard therapy respectively, eight patients per group have recurred and died. The progression free and overall survival are the same in both groups.</p> <p>Conclusion</p> <p>The results of this study suggest that radical hysterectomy can be used after EBRT-CT without compromising survival in FIGO stage IB2-IIB cervical cancer patients in settings were brachytherapy is not available. A randomized study is needed to uncover the value of surgery after EBRT-CT.</p

Prognostic significance of pathological response after neoadjuvant chemotherapy or chemoradiation for locally advanced cervical carcinoma

BACKGROUND: Cisplatin-based chemoradiation is the standard of care for locally advanced cervical cancer patients; however, neoadjuvant modalities are currently being tested. Neoadjuvant studies in several tumor types have underscored the prognostic significance of pathological response for survival; however there is a paucity of studies in cervical cancer investigating this issue. METHODS: Four cohorts of patients with locally advanced cervical carcinoma (stages IB2-IIIB); included prospectively in phase II protocols of either neoadjuvant chemotherapy with 1) cisplatin-gemcitabine, 2) oxaliplatin-gemcitabine, 3) carboplatin-paclitaxel or 4) chemoradiation with cisplatin or cisplatin-gemcitabine followed by radical hysterectomy were analyzed for pathological response and survival. RESULTS: One-hundred and fifty three (86%) of the 178 patients treated within these trials, underwent radical hysterectomy and were analyzed. Overall, the mean age was 44.7 and almost two-thirds were FIGO stage IIB. Pathological response rates were as follows: Complete (pCR) in 60 cases (39.2%), Near-complete (p-Near-CR) in 24 (15.6 %) and partial (pPR) in 69 cases (45.1%). A higher proportion rate of pCR was observed in patients treated with chemoradiotherapy (with cisplatin [19/40, 47.5%]; or with cisplatin-gemcitabine [24/41, 58.5%] compared with patients receiving only chemotherapy, 6/23 (26%), 3/8 (37.5%) and 8/41 (19.5%) for cisplatin-gemcitabine, oxaliplatin-gemcitabine and carboplatin-paclitaxel respectively [p = 0.0001]). A total of 29 relapses (18.9%) were documented. The pathological response was the only factor influencing on relapse, since only 4/60 (6.6%) patients with pCR relapsed, compared with 25/93 (26.8%) patients with viable tumor, either pNear-CR or pPR (p = 0.001). Overall survival was 98.3% in patients with pCR versus 83% for patients with either pNear-CR or pPR (p = 0.009). CONCLUSION: Complete pathological response but no Near-complete and partial responses is associated with longer survival in cervical cancer patients treated with neoadjuvant chemotherapy or chemoradiotherapy

Antineoplastic effects of the DNA methylation inhibitor hydralazine and the histone deacetylase inhibitor valproic acid in cancer cell lines

BACKGROUND: Among the epigenetic alterations occurring in cancer, DNA hypermethylation and histone hypoacetylation are the focus of intense research because their pharmacological inhibition has shown to produce antineoplastic activity in a variety of experimental models. The objective of this study was to evaluate the combined antineoplastic effect of the DNA methylation inhibitor hydralazine and the histone deacetylase inhibitor valproic acid in a panel of cancer cell lines. RESULTS: Hydralazine showed no growth inhibitory effect on cervical, colon, breast, sarcoma, glioma, and head & neck cancer cell lines when used alone. On the contrary, valproic acid showed a strong growth inhibitory effect that is potentiated by hydralazine in some cell lines. Individually, hydralazine and valproic acid displayed distinctive effects upon global gene over-expression but the number of genes over-expressed increased when cells were treated with the combination. Treatment of HeLa cells with hydralazine and valproic acid lead to an increase in the cytotoxicity of gemcitabine, cisplatin and adriamycin. A higher antitumor effect of adriamycin was observed in mice xenografted with human fibrosarcoma cells when the animals were co-treated with hydralazine and valproic acid. CONCLUSION: Hydralazine and valproic acid, two widely used drugs for cardiovascular and neurological conditions respectively have promising antineoplastic effects when used concurrently and may increase the antitumor efficacy of current cytotoxic agents

Histone acetylation and histone deacetylase activity of magnesium valproate in tumor and peripheral blood of patients with cervical cancer. A phase I study

BACKGROUND: The development of cancer has been associated with epigenetic alterations such as aberrant histone deacetylase (HDAC) activity. It was recently reported that valproic acid is an effective inhibitor of histone deacetylases and as such induces tumor cell differentiation, apoptosis, or growth arrest. METHODS: Twelve newly diagnosed patients with cervical cancer were treated with magnesium valproate after a baseline tumor biopsy and blood sampling at the following dose levels (four patients each): 20 mg/kg; 30 mg/kg, or 40 mg/kg for 5 days via oral route. At day 6, tumor and blood sampling were repeated and the study protocol ended. Tumor acetylation of H3 and H4 histones and HDAC activity were evaluated by Western blot and colorimetric HDAC assay respectively. Blood levels of valproic acid were determined at day 6 once the steady-state was reached. Toxicity of treatment was evaluated at the end of study period. RESULTS: All patients completed the study medication. Mean daily dose for all patients was 1,890 mg. Corresponding means for the doses 20-, 30-, and 40-mg/kg were 1245, 2000, and 2425 mg, respectively. Depressed level of consciousness grade 2 was registered in nine patients. Ten patients were evaluated for H3 and H4 acetylation and HDAC activity. After treatment, we observed hyperacetylation of H3 and H4 in the tumors of nine and seven patients, respectively, whereas six patients demonstrated hyperacetylation of both histones. Serum levels of valproic acid ranged from 73.6–170.49 μg/mL. Tumor deacetylase activity decreased in eight patients (80%), whereas two had either no change or a mild increase. There was a statistically significant difference between pre and post-treatment values of HDAC activity (mean, 0.36 vs. 0.21, two-tailed t test p < 0.0264). There was no correlation between H3 and H4 tumor hyperacetylation with serum levels of valproic acid. CONCLUSION: Magnesium valproate at a dose between 20 and 40 mg/kg inhibits deacetylase activity and hyperacetylates histones in tumor tissues