Development of an in vitro chemo-radiation response assay for cervical carcinoma

Synergistic locoregional chemoradiotherapy using a composite liposome-in-gel system as an injectable drug depot

The use of radiosensitizers in clinical radiotherapy is limited by systemic toxicity. The biopolymeric, biodegradable, injectable liposome-in-gel-paclitaxel (LG-PTX) system was developed for regional delivery of the radiosensitizer paclitaxel (PTX), and its efficacy was evaluated with concurrent fractionated radiation. LG-PTX is composed of nano-sized drug-loaded fluidizing liposomes, which are incorporated into a porous biodegradable gellan hydrogel. This allows enhanced drug permeation while maintaining a localization of the drug depot. LG-PTX had an IC₅₀ of 325±117 nM in B16F10 melanoma cells, and cytotoxicity with concurrent doses of fractionated radiation showed significant increase in apoptotic cells (75%) compared to radiation (39%) or LG-PTX (43%) alone. Peri-tumoral injection in tumor-bearing mice showed PTX localization in the tumor 2 hours after administration, with no drug detected in plasma or other organs. LG-PTX administration with doses of focal radiation (5×3 Gy) significantly reduced tumor volumes compared to control (6.4 times) and radiation alone (1.6 times) and improved animal survival. LG-PTX thus efficiently localizes the drug at the tumor site and synergistically enhances the effect of concurrent radiotherapy. This novel liposome-in-gel system can potentially be used as a platform technology for the delivery of radiosensitizing drugs to enhance the efficacy of chemoradiotherapy.

In vitro chemoresponse analysis of cervical cancer patient specimens

PURPOSE

The objective of this study was to report the results of in vitro chemoresponse analysis of primary, metastatic, and recurrent human cervical cancers.

METHODS

There were 557 tumor specimens submitted for testing from August 2006 to June 2010. Single agents tested were cisplatin, carboplatin, paclitaxel, docetaxel, epirubicin, fluorouracil, 4-hydroxy ifosfamide (active metabolite of ifosfamide), SN-38 (active metabolite of irinotecan), topotecan, and vinorelbine. Doublets tested were carboplatin/paclitaxel and cisplatin/topotecan. Tumor response was determined from dose-response curves. Results were scored as responsive, intermediate, or nonresponsive. Chemoresponse was reported as the combined responsive and intermediate results.

RESULTS

Three hundred fifty-three (63.4%) of 557 submitted specimens were successfully assayed. Confirmation of histology and tumor status (primary, metastatic, or recurrent) was available for 273 specimens. The chemoresponse of the most active agents in primary cancers (n = 151) was 75% for SN-38, 71% for 4-hydroxy ifosfamide, 62% for topotecan, and 73% for carboplatin/paclitaxel. The chemoresponse of metastatic cancers (n = 66) was 54% for SN-38, 51% for 4-hydroxy ifosfamide, 44% for epirubicin, and 53% for carboplatin/paclitaxel. The chemoresponse for recurrent cancers (n = 56) was 44% for epirubicin, 41% for 4-hydroxy ifosfamide, 39% for vinorelbine, 39% for paclitaxel, 36% for topotecan, 46% for carboplatin/paclitaxel, and 35% for cisplatin/topotecan. The overall chemoresponse was greater in primary cancers (58%) than in recurrent cancers (35%) (P < 0.0001).

CONCLUSIONS

In vitro chemoresponse analysis of cervical cancer biospecimens is feasible. Chemoresponse results are variable depending on tumor status. Clinical studies of assay-directed therapy should be developed.

Prospective evaluation of an in vitro radiation resistance assay in locally advanced cancer of the uterine cervix: a Southwest Oncology Group Study

OBJECTIVES

To investigate the feasibility of performing a fresh-tissue, in vitro radiation resistance assay (IVRRA) in a cooperative group setting and to assess the association of IVRRA results with clinical outcomes.

METHODS

Women with Stages IIB-IVA carcinoma of the uterine cervix without obvious para-aortic lymphadenopathy on imaging were eligible. Primary tumor biopsies were shipped to a central testing facility where agar-based cell suspensions were exposed to 300 cGy of RT ± cisplatin and cultured for 5 days. ³H-thymidine incorporation was used to determine percent cell inhibition (PCI) of test specimen compared to that of the untreated control. Tumors were considered to exhibit extreme radiation resistance (ERR), intermediate radiation resistance (IRR) or low radiation resistance (LRR) based on a standard data set from 39 previously studied specimens. Standardized doses of external beam radiation and intracavitary brachytherapy, when feasible, in addition to platinum-based chemotherapy were mandated. Progression-free survival (PFS) was the primary endpoint. Clinical response and overall survival (OS) were secondary endpoints. Clinical investigators were blinded to assay data and vice versa.

RESULTS

Thirty-six patients were enrolled, but analysis was limited to 17 patients whose specimens were adequate for IVRRA. The median follow-up time among patients still alive at last contact was 40 months (range: 0-56 months). There was no association between IVRRA and response. In the Cox model, IRR/ERR tumors showed worse PFS [HR = 11.2 (95% CI 1.3-96, p = 0.03)] and worse OS [HR=11.7 (95% CI 1.4-99.6, p = 0.03)] compared to LRR tumors when IVRRA was performed with RT alone, but there were no associations between IVRRA and PFS or OS when cisplatin was added to the IVRRA.

CONCLUSIONS

IVRRA (RT alone) results correlated with PFS and OS in this prospective trial, but follow-up trials are indicated to address feasibility and to confirm results in an expanded cohort. If confirmed, IVRRA could potentially direct molecular identification of novel targeted therapeutic approaches which might counteract radiation resistance.

Predicting the response of advanced cervical and ovarian tumors to therapy

The management of advanced cervical and ovarian cancers remains a significant challenge as many women fail to respond to recommended therapy, resulting in disease progression and ultimately patient death. Because of tumor heterogeneity, it is rare for all cancers of a particular type to respond to a specific therapy; and, as a result, many patients receive treatment from which they derive little or no benefit, leading to increased morbidity and undue costs. A marker that could rapidly predict or forecast disease outcome would clearly be beneficial in allowing the administration of a tailored regime for each patient while reducing toxicity and cost. Traditional prognostic factors of tumor size, grade, and stage are not ideal for predicting patient outcome, whereas the use of in vitro assays to detect chemosensitivity or resistance has not yet translated into routine clinical practice. Similarly, biomarkers and tumor markers vary in their predictive ability. DNA array technology offers great promise in predicting the response to therapy based on gene expression profiles, and can allow for targeted therapies against specific molecular alterations that cause disease. Imaging techniques, particularly those with the ability to characterize biological tissues and provide functional, structural, and molecular information, have the potential to noninvasively integrate physical and metabolic information. These include F-18-fluorodeoxyglucose positron emission tomography, dynamic contrast-enhanced magnetic resonance imaging, and diffusion weighted magnetic resonance imaging, all techniques that attempt to evaluate and predict therapy response and so influence clinical outcome. This review examines different methods of predicting the response to treatment in advanced cervical and ovarian tumors.

TARGET AUDIENCE

Obstetricians & Gynecologists, Family Physicians.

LEARNING OBJECTIVES

After completion of this article, the reader should be able to describe why prediction of response to therapy for cervical and ovarian cancers is important, describe obstacles to use of in vitro assays to predict outcomes for therapy for ovarian and cervical cancers, and explain potentially new predictive markers.

Effects of cisplatin and gamma-irradiation on cell survival, the induction of chromosomal aberrations and apoptosis in SW-1573 cells

PURPOSE

Cisplatin was found to radiosensitize SW-1573 cells by inhibition of PLDR. Therefore, it was investigated whether cisplatin combined with gamma-radiation leads to an increase in the number of chromosomal aberrations or apoptotic cells compared with radiation alone.

METHODS

Confluent cultures of the human lung carcinoma cell line SW-1573 were treated with 1 microM cisplatin for 1 h, 4 Gy gamma-radiation, or a combination of both. Cell survival was studied by the clonogenic assay. Aberrations were analysed by FISH in prematurely condensed chromosomes (PCC) and the induction of apoptosis by counting fragmented nuclei.

RESULTS

A radiosensitizing effect of cisplatin on cell survival was observed if time for PLDR was allowed. An increased number of chromosomal fragments were observed immediately after irradiation compared with 24 h after irradiation whereas color junctions are only formed 24 h after irradiation. No increase in chromosomal aberrations was found after combined treatment, but a significantly enhanced number of fragmented nuclei were observed when confluent cultures were replated after allowing PLDR.

CONCLUSION

The inhibition of PLDR by cisplatin in delayed plated SW-1573 cells did not increase chromosomal aberrations, but increased the induction of apoptosis.

Gene expression profiling of in vitro radiation resistance in cervical carcinoma: a feasibility study

OBJECTIVE(S)

To determine the feasibility of integrating an in vitro chemo-radiation response assay (IVRRA) with a gene microarray system to investigate the molecular patterns of expression that contribute to radiation resistance in cervical cancer.

METHODS

Viable primary untreated cervical cancer specimens were obtained and exposed to gamma irradiation at a dose of 3 Gy in the IVRRA to determine in vitro radiation sensitivity. RNA was purified for microarray analysis with the Affymetrix Human Genome U95A Array carrying more than 12,000 gene probes. Gene expression analysis was performed, and specimen transcript patterns were correlated with radiation response using an iteration analysis model and Pearson's correlation coefficient.

RESULTS

A feasibility set of eight tumor specimens was studied. Tumors were classified into 4 extreme (ERR), 2 intermediate (IRR) and 2 low radiation resistance (LRR) categories. An intrinsic radiation response gene set of 54 genes transcripts with 100% accuracy for the classification of each tumor's radiation response category was identified.

CONCLUSION(S)

Gene sets associated with in vitro radiation response profiles in cervical cancer can be generated using the IVRRA and microarray technology. This has direct applications to the study of the biological pathways contributing to radiation resistance and may lead to the development of alternative treatment modalities. The potential of these technologies for cancers in which radiotherapy is employed warrants further investigation.

The action of ionizing irradiation alone or in combination with cisplatin on malignant cells: Investigations in vitro

The paper gives a brief review of the literature data based on in vitro investigations of cytotoxic action of cisplatin and irradiation, applied alone or in combination, to carcinoma cell lines and fresh tumor explants. Presented data, observed in the light of data obtained in clinics, indicate that in vivo some additional tumor destructive activity might be induced by applied therapy. Therefore examinations of the antitumor effect of some treatment need to be more complex and must include determination of the effects of applied therapy on set of parameters, which control tumor growth in vivo.