Radiosensitization with chemotherapeutic agents

Progression in low-intensity ultrasound-induced tumor radiosensitization

BACKGROUND

Radiotherapy (RT) is a widely utilized tumor treatment approach, while a significant obstacle in this treatment modality is the radioresistance exhibited by tumor cells. To enhance the effectiveness of RT, scientists have explored radiosensitization approaches, including the use of radiosensitizers and physical stimuli. Nevertheless, several approaches have exhibited disappointing results including adverse effects and limited efficacy. A safer and more effective method of radiosensitization involves low-intensity ultrasound (LIUS), which selectively targets tumor tissue and enhances the efficacy of radiation therapy.

METHODS

This review summarized the tumor radioresistance reasons and explored LIUS potential radiosensitization mechanisms. Moreover, it covered diverse LIUS application strategies in radiosensitization, including the use of LIUS alone, ultrasound-targeted intravascular microbubble destruction, ultrasound-mediated targeted radiosensitizers delivery, and sonodynamic therapy. Lastly, the review presented the limitations and prospects of employing LIUS-RT combined therapy in clinical settings, emphasizing the need to connect research findings with practical applications.

RESULTS AND CONCLUSION

LIUS employs cost-effective equipment to foster tumor radiosensitization, curtail radiation exposure, and elevate the quality of life for patients. This efficacy is attributed to LIUS's ability to utilize thermal, cavitation, and mechanical effects to overcome tumor cell resistance to RT. Multiple experimental analyses have underscored the effectiveness of LIUS in inducing tumor radiosensitization using diverse strategies. While initial studies have shown promising results, conducting more comprehensive clinical trials is crucial to confirm its safety and effectiveness in real-world situations.

Oncolytic Virus-Driven Biotherapies from Bench to Bedside

With advances in cancer biology and an ever-deepening understanding of molecular virology, oncolytic virus (OV)-driven therapies have developed rapidly and become a promising alternative to traditional cancer therapies. In recent years, satisfactory results for oncolytic virus therapy (OVT) are achieved at both the cellular and organismal levels, and efforts are being increasingly directed toward clinical trials. Unfortunately, OVT remains ineffective in these trials, especially when performed using only a single OV reagent. In contrast, integrated approaches, such as using immunotherapy, chemotherapy, or radiotherapy, alongside OVT have demonstrated considerable efficacy. The challenges of OVT in clinical efficacy include the restricted scope of intratumoral injections and poor targeting of intravenous administration. Further optimization of OVT delivery is needed before OVs become a viable therapy for tumor treatment. In this review, the development process and antitumor mechanisms of OVs are introduced. The advances in OVT delivery routes to provide perspectives and directions for the improvement of OVT delivery are highlighted. This review also discusses the advantages and limitations of OVT monotherapy and combination therapy through the lens of recent clinical trials and aims to chart a course toward safer and more effective OVT strategies.

Superparamagnetic Iron Oxide Nanoparticles (SPION): From Fundamentals to State-of-the-Art Innovative Applications for Cancer Therapy

Despite significant advances in cancer therapy over the years, its complex pathological process still represents a major health challenge when seeking effective treatment and improved healthcare. With the advent of nanotechnologies, nanomedicine-based cancer therapy has been widely explored as a promising technology able to handle the requirements of the clinical sector. Superparamagnetic iron oxide nanoparticles (SPION) have been at the forefront of nanotechnology development since the mid-1990s, thanks to their former role as contrast agents for magnetic resonance imaging. Though their use as MRI probes has been discontinued due to an unfavorable cost/benefit ratio, several innovative applications as therapeutic tools have prompted a renewal of interest. The unique characteristics of SPION, i.e., their magnetic properties enabling specific response when submitted to high frequency (magnetic hyperthermia) or low frequency (magneto-mechanical therapy) alternating magnetic field, and their ability to generate reactive oxygen species (either intrinsically or when activated using various stimuli), make them particularly adapted for cancer therapy. This review provides a comprehensive description of the fundamental aspects of SPION formulation and highlights various recent approaches regarding in vivo applications in the field of cancer therapy.

Concurrent versus sequential chemoradiotherapy for unresectable locally advanced stage III non-small cell lung cancer: Retrospective analysis in a single United Kingdom cancer centre

INTRODUCTION

Stage III unresectable locally advanced non-small cell lung cancer (NSCLC) is a complex disease group with poor long-term survival. Clinical data suggests curative intent concurrent chemoradiotherapy (CCRT) is superior to a sequential (SCRT) approach but comes with additional toxicities. We report real world data regarding overall survival and toxicity to aid clinical decision making in balancing optimal management and treatment tolerability.

METHODS

Retrospective analysis of survival data, treatment toxicities, and rates of treatment completion were performed for 241 patients who underwent chemoradiotherapy for unresectable stage III NSCLC within Leeds Cancer Centre from January 2011 to December 2014.

RESULTS

Median survival was 18.8 months following SCRT compared to 22.7 months following CCRT HR 0.90 (95% CI 0.67-1.20, P = 0.46). Median follow up was 21 months. The clinical benefit rate for CCRT compared to SCRT was 22.7% versus 24%. In the CCRT group 63.8% patients completed treatment compared to 46% in the SCRT arm (P < 0.01). 90-day mortality rates were low in CCRT and SCRT cohorts at 4.3% and 1% respectively. There was greater pulmonary toxicity following CCRT versus SCRT (13.5% versus 1.0%, P < 0.01).

CONCLUSION

This study provides real world data regarding the radical treatment of unresectable stage III NSCLC. Increased hospital admissions and pneumonitis toxicities did not adversely affect treatment completion for those undergoing CCRT; this was likely due to careful patient selection based on performance status. SCRT still remains an important treatment modality for patients who cannot tolerate the upfront CCRT approach but could still be treated with curative intent.

Synchronization of Nanoparticle Sensitization and Radiosensitizing Chemotherapy through Cell Cycle Arrest Achieving Ultralow X-ray Dose Delivery to Pancreatic Tumors

Pancreatic cancer is among the leading causes of cancer-related death and remains a formidable therapeutic challenge. To date, surgical resection and chemotherapy have been the standards of care. Methotrexate (MTX), which is recognized as a refractory drug for pancreatic cells, was conjugated to the surface of LiYF₄:Ce³⁺ nanoparticles (NP-MTX) through a photocleavable linker molecule. When LiYF₄:Ce³⁺ NPs are stimulated by X-rays, they emit light, which induces the photocleavage of the photolabile linker molecule to release MTX. MTX can target pancreatic tumors, which overexpress folic acid (FA) receptors and are internalized into the cell through receptor-mediated endocytosis. The synergistic effect of the NP-MTX treatment initiated by X-ray irradiation occurs due to the combination of nanoparticle sensitization and the radiosensitizing chemotherapy of the photocleaved MTX molecule. This dual sensitization effect mediated by NP-MTX enabled 40% dose enhancement, which corresponded with an increase in the generation of cytotoxic cellular reactive oxygen species (ROS) and enhanced S phase arrest within the cell cycle. The delivery of an ultralow radiation dose of 0.1 Gy resulted in the photocleavage of MTX from NP-MTX, and this strategy demonstrated in vivo efficacy against AsPC-1 and PANC-1 xenografted pancreatic tumors.

Why Concurrent CDDP and Radiotherapy Has Synergistic Antitumor Effects: A Review of In Vitro Experimental and Clinical-Based Studies

Chemo-radiotherapy, which combines chemotherapy with radiotherapy, has been clinically practiced since the 1970s, and various anticancer drugs have been shown to have a synergistic effect when used in combination with radiotherapy. In particular, cisplatin (CDDP), which is often the cornerstone of multi-drug combination cancer therapies, is highly versatile and frequently used in combination with radiotherapy for the treatment of many cancers. Therefore, the mechanisms underlying the synergistic effect of CDDP and radiotherapy have been widely investigated, although no definitive conclusions have been reached. We present a review of the combined use of CDDP and radiotherapy, including the latest findings, and propose a mechanism that could explain their synergistic effects. Our hypothesis involves the concepts of overlap and complementation. “Overlap” refers to the overlapping reactions of CDDP and radiation-induced excessive oxidative loading, which lead to accumulating damage to cell components, mostly within the cytoplasm. “Complementation” refers to the complementary functions of CDDP and radiation that lead to DNA damage, primarily in the nucleus. In fact, the two concepts are inseparable, but conceptualizing them separately will help us understand the mechanism underlying the synergism between radiation therapy and other anticancer drugs, and help us to design future radiosensitizers.

Potential of MRI in Radiotherapy Mediated by Small Conjugates and Nanosystems

Radiation therapy has made tremendous progress in oncology over the last decades due to advances in engineering and physical sciences in combination with better biochemical, genetic and molecular understanding of this disease. Local delivery of optimal radiation dose to a tumor, while sparing healthy surrounding tissues, remains a great challenge, especially in the proximity of vital organs. Therefore, imaging plays a key role in tumor staging, accurate target volume delineation, assessment of individual radiation resistance and even personalized dose prescription. From this point of view, radiotherapy might be one of the few therapeutic modalities that relies entirely on high-resolution imaging. Magnetic resonance imaging (MRI) with its superior soft-tissue resolution is already used in radiotherapy treatment planning complementing conventional computed tomography (CT). Development of systems integrating MRI and linear accelerators opens possibilities for simultaneous imaging and therapy, which in turn, generates the need for imaging probes with therapeutic components. In this review, we discuss the role of MRI in both external and internal radiotherapy focusing on the most important examples of contrast agents with combined therapeutic potential.

[Results of surgical and combined treatment of non-small cell lung cancer]

AIM

To study the results of surgical and combined treatment of non-small cell lung cancer stage III using preoperative chemotherapy and intraoperative radiotherapy.

MATERIAL AND METHODS

The study included 152 patients with non-small cell lung cancer stage III. Overall and recurrence-free 5-year survival were 20.4% and 14.3% respectively. These values were significantly higher in case of combined treatment consisting of radical surgery and intraoperative radiotherapy (29.2% and 18.7% respectively, p<0.05).

RESULTS

The best results were obtained in case of preoperative chemotherapy with paclitaxel/carboplatin, radical surgery and intraoperative radiotherapy on background of radiosensitization with cisplatin. Overall and recurrence-free 5-year survival were 47.9% and 41.7% respectively (p<0.05). Incidence of postoperative complications and mortality rate did not significantly differ between surgical and combined treatment (p>0.05).

Radiosensitization of TPGS-emulsified docetaxel-loaded poly(lactic-co-glycolic acid) nanoparticles in CNE-1 and A549 cells

Docetaxel is among the most effective radiosensitizers. It is widely used as radiosensitizer in many tumors, including head and neck carcinoma. Nevertheless, poor solubility and severe hypersensitivity limit its clinical use and its therapeutic effect remains to be improved. In this study, docetaxel-loaded polymeric nanoparticles were prepared by nanoprecipitation method to be new radiosensitizer with lower side effects and higher efficacy. The physiochemical characteristics of the nanoparticles were studied. Two human tumor cell lines which are resistant to radiotherapy were used in this research. We have compared the radioenhancement efficacy of docetaxel-loaded nanoparticles with docetaxel in A549 and CNE-1 cells. Compared with docetaxel, radiosensitization of docetaxel-loaded nanoparticles was improved significantly (sensitization enhancement ratio in A549 increased 1.24-fold to 1.68-fold when the radiation was applied 2 h after the drug, p < 0.01, sensitization enhancement ratio in CNE-1 increased 1.32-fold to 1.61-fold, p < 0.05). We explored the mechanisms for the radiosensitization efficiency and the difference between docetaxel and docetaxel-loaded poly(lactic-co-glycolic acid) (PLGA) nanoparticles. The improved radiosensitization efficacy was associated with enhanced G2/M arrest, promoted apoptosis and the role of D-alpha-tocopheryl polyethylene glycol 1000 succinate which will enhance the cell uptake and inhibit the multiple drug resistance. Moreover, the radiosensitization efficacy of docetaxel-loaded nanoparticles was more prominent than docetaxel. In conclusion, tocopheryl polyethylene glycol 1000 succinate-emulsified docetaxel-loaded PLGA nanoparticles were more efficacious and fewer adverse effects were observed than with the commercial docetaxel formulation. Thus, PLGA nanoparticles hold promise as a radiosensitizing agent.

Chemoradiotherapeutic Magnetic Nanoparticles for Targeted Treatment of Nonsmall Cell Lung Cancer

Lung cancer is the leading cause of cancer-related death in the United States and approximately 85% of all lung cancers are classified as nonsmall cell (NSCLC). We here use an innovative approach that may ultimately allow for the clinician to target tumors and aggressively reduce tumor burden in patients with NSCLC. In this study, a platinum (Pt)-based chemotherapeutic (cisplatin, carboplatin, or oxaliplatin) and holmium-165 (Ho), which can be neutron-activated to produce the holmium-166 radionuclide, have been incorporated together in a garnet magnetic nanoparticle (HoIG-Pt) for selective delivery to tumors using an external magnet. The synthesized magnetic HoIG nanoparticles were characterized using PXRD, TEM, ICP-MS, and neutron-activation. Platinum(II) drugs were incorporated onto HoIG, and these were characterized using FTIR, EDX, ICP-MS, and zeta potential measurements, and in vitro and in vivo studies were performed using a HoIG-platinum system. Results indicate that neutron-activated (166)HoIG-cisplatin is more toxic toward NSCLC A549 cells than is blank (166)HoIG and free cisplatin, and that when an external magnetic field is applied in vivo, higher tumor to liver ratios of Ho are observed than when no magnet is applied, suggesting that magnetic targeting is achieved using this system. Furthermore, an efficacy study demonstrated the inhibition of tumor growth by chemoradiotherapeutic magnetic nanoparticles, compared to no treatment controls.

Assessing the Effects of Concurrent versus Sequential Cisplatin/Radiotherapy on Immune Status in Lung Tumor-Bearing C57BL/6 Mice

Concurrent and sequential cisplatin-based chemoradiotherapy regimens are standard therapeutic approaches in cancer treatment. Recent clinical data suggest that these different dosing schedules may adversely affect antigen-specific immunotherapy. The goal of the present preclinical study was to explore the effects of concurrent and sequential cisplatin/radiotherapy on immune status in a lung cancer mouse model. A total of 150 C57BL/6 mice were randomized into six treatment groups: control; 8 Gy thoracic radiotherapy (dose schedules 1 and 2); cisplatin 2.5 mg/kg i.p.; cisplatin + radiotherapy (concurrent); and cisplatin + radiotherapy (sequential; n = 25, all groups). At the end of the study (week 41), serum cytokines were assessed by multiplex immunoassay, surface markers of spleen-derived lymphocytes were assessed by immunostaining and flow cytometry, lung tumor expression of programmed death ligands 1 and 2 (PD-L1/2) was evaluated by immunohistochemistry, and miRNA profiling was performed in serum and lymphocytes by quantitative real-time PCR. Lung whole mounts were prepared to assess treatment effects on lung tumor foci formation. The results showed that sequential chemoradiotherapy (two cycles of cisplatin followed by 8 Gy radiotherapy) had equivalent antitumor activity as concurrent therapy. However, sequential cisplatin/radiotherapy resulted in significant differences in several immune response biomarkers, including regulatory T cells, miR-29c, expression of costimulatory molecule CD28, and serum IFNγ. PD-L1 and PD-L2 were strongly expressed in tumor foci, but no trend was seen between groups. These results suggest that monitoring immune status may be necessary when designing treatment regimens combining immunotherapy with chemoradiotherapy.

Phase I study of vincristine, irinotecan, and ¹³¹I-metaiodobenzylguanidine for patients with relapsed or refractory neuroblastoma: a new approaches to neuroblastoma therapy trial

PURPOSE

(131)I-metaiodobenzylguanidine (MIBG) is a targeted radiopharmaceutical with activity in patients with relapsed or refractory neuroblastoma. Irinotecan is a known radiosensitizer with activity in neuroblastoma. This phase I study aimed to determine the recommended phase 2 dose of MIBG together with fixed doses of vincristine and irinotecan.

EXPERIMENTAL DESIGN

Patients 1 to 30 years old with relapsed or refractory neuroblastoma and MIBG-avid tumors were eligible. All patients had autologous hematopoietic stem cells (PBSC) available and met standard phase I organ function requirements. Irinotecan (20 mg/m(2)/dose IV) was given on days 0 to 4 and 7 to 11, with vincristine (1.5 mg/m(2) IV) on days 0 and 7. MIBG was given on day 1 following a 3 + 3 phase I dose escalation design starting at 8 mCi/kg MIBG. PBSCs were administered at dose level 8 mCi/kg for prolonged myelosuppression and for all patients at 12 mCi/kg or more.

RESULTS

Twenty-four patients evaluable for dose escalation (median age, 6.7 years; range, 1.9-26.8 years) received 1 (n = 17), 2 (n = 5), or 3 (n = 2) cycles of therapy. Myelosuppression and diarrhea were the most common toxicities. Two of 6 patients at the 18 mCi/kg dose level had dose-limiting toxicity (DLT), including one with protocol-defined DLT with prolonged mild aspartate aminotransferase elevation. Eighteen mCi/kg was the recommended phase 2 dose. Six additional patients were treated at 18 mCi/kg, with one additional DLT. Responses (2 complete and 4 partial responses) occurred in 6 of 24 (25%) evaluable patients.

CONCLUSIONS

MIBG is tolerable and active at 18 mCi/kg with standard doses of vincristine and irinotecan.

Effects of phytochemicals on ionization radiation-mediated carcinogenesis and cancer therapy

Ionizing radiation (IR)-induced cellular damage is implicated in carcinogenesis as well as therapy of cancer. Advances in radiation therapy have led to the decrease in dosage and localizing the effects to the tumor; however, the development of radioresistance in cancer cells and radiation toxicity to normal tissues are still the major concerns. The development of radioresistance involves several mechanisms, including the activation of mitogenic and survival signaling, induction of DNA repair, and changes in redox signaling and epigenetic regulation. The current strategy of combining radiation with standard cytotoxic chemotherapeutic agents can potentially lead to unwanted side effects due to both agents. Thus agents are needed that could improve the efficacy of radiation killing of cancer cells and prevent the damage to normal cells and tissues caused by the direct and bystander effects of radiation, without have its own systemic toxicity. Chemopreventive phytochemicals, usually non-toxic agents with both cancer preventive and therapeutic activities, could rightly fit in this approach. In this regard, naturally occurring compounds, including curcumin, parthenolide, genistein, gossypol, ellagic acid, withaferin, plumbagin and resveratrol, have shown considerable potential. These agents suppress the radiation-induced activation of receptor tyrosine kinases and nuclear factor-κB signaling, can modify cell survival and DNA repair efficacy, and may potentiate ceramide signaling. These radiosensitizing and counter radioresistance mechanisms of phytochemicals in cancer cells are also associated with changes in epigenetic gene regulation. Because radioresistance involves multiple mechanisms, more studies are needed to discover novel phytochemicals having multiple mechanisms of radiosensitization and to overcome radioresistance of cancer cells. Pre-clinical studies are needed to address the appropriate dosage, timing, and duration of the application of phytochemicals with radiation to justify clinical trials. Nonetheless, some phytochemicals in combination with IR may play a significant role in enhancing the therapeutic index of cancer treatment.

Tumor Growth Inhibitory Effect of Juglone and Its Radiation Sensitizing Potential

The present study aimed at evaluating the anticancer and radiosensitizing potential of juglone against a chemoresistant and radioresistant tumor (B16F1 melanoma) growing on C57BL/6J mice. Volume doubling time, growth delay, and median survival were used to assess the in vivo anticancer and radiosensitizing potential of juglone. In vitro radiosensitizing potential of juglone was studied using clonogenic, comet, and reactive oxygen species induction assays. Treatment of tumor-bearing mice with sublethal doses of juglone caused a dose-dependent inhibition of tumor growth as evident from the growth delay and median survival values. Comet assay using tumor tissue and blood showed differential toxicity of juglone, where higher levels of DNA damage was seen in tumor tissue compared with blood cells. Pretreatment of tumor-bearing mice with optimum dose of juglone before radiation resulted in significant tumor growth inhibition compared with radiation alone. From the clonogenic assay, the authors observed a sensitization enhancement ratio of 1.37 for the combination treatment compared with radiation alone. Furthermore, comet assay studies revealed the potential of juglone to enhance the radiation-induced DNA damage and cause a delay in its repair. Juglone pretreatment before radiation also resulted in a significant elevation in the intracellular reactive oxygen species levels compared with radiation alone. In conclusion, the results of this study show the potential of juglone to inhibit the growth of melanoma in vivo. The study also revealed the potential of juglone to augment the radiation-induced cell death of melanoma cells, which may be attributed to oxidative stress–mediated DNA damage and its delayed repair.

Differential activation of NF-κB and nitric oxide in lymphocytes regulates in vitro and in vivo radiosensitivity

Lymphocytes are more sensitive to radiation in vivo than in vitro. However, the mechanism of this differential response is poorly understood. In the present study, it was found that the lipid peroxidation and cell death were significantly higher in lymphocytes following whole body irradiation (WBI) as compared to lymphocytes exposed to radiation in vitro. EL-4 cells transplanted in mice were also more sensitive to radiation than EL-4 cells irradiated in vitro. DNA repair, as assessed by comet assay, was significantly faster in lymphocytes exposed to 4Gy radiation in vitro as compared to that in lymphocytes obtained from whole body irradiated mice exposed to the same dose of radiation. This was associated with increased NF-κB activation in response to genotoxic stress and lesser activation of caspase in lymphocytes in vitro compared to in vivo. To explain the differential radiosensitivity, we postulated a role of nitric oxide, an extrinsic diffusible mediator of radiosensitivity that has also been implicated in DNA repair inhibition. Nitric oxide levels were significantly elevated in the plasma of whole body irradiated mice but not in the supernatant of cells irradiated in vitro. Addition of sodium nitroprusside (SNP), a nitric oxide donor to cells irradiated in vitro inhibited the repair of DNA damage and enhanced apoptosis (increased Bax to Bcl-2 ratio). Administration of l-NAME, a nitric oxide synthase inhibitor, to mice significantly protected lymphocytes against WBI-induced DNA damage and inhibited in vivo radiation-induced production of nitric oxide. These results confirm that the observed differential radiosensitivity of lymphocytes was due to slow repair of DNA due to nitric oxide production in vivo.

SNPs in genes coding for ROS metabolism and signalling in association with docetaxel clearance

The dose of docetaxel is currently calculated based on body surface area and does not reflect the pharmacokinetic, metabolic potential or genetic background of the patients. The influence of genetic variation on the clearance of docetaxel was analysed in a two-stage analysis. In step one, 583 single-nucleotide polymorphisms (SNPs) in 203 genes were genotyped on samples from 24 patients with locally advanced non-small cell lung cancer. We found that many of the genes harbour several SNPs associated with clearance of docetaxel. Most notably these were four SNPs in EGF, three SNPs in PRDX4 and XPC, and two SNPs in GSTA4, TGFBR2, TNFAIP2, BCL2, DPYD and EGFR. The multiple SNPs per gene suggested the existence of common haplotypes associated with clearance. These were confirmed with detailed haplotype analysis. On the basis of analysis of variance (ANOVA), quantitative mutual information score (QMIS) and Kruskal-Wallis (KW) analysis SNPs significantly associated with clearance of docetaxel were confirmed for GSTA4, PRDX4, TGFBR2 and XPC and additional putative markers were found in CYP2C8, EPHX1, IGF2, IL1R2, MAPK7, NDUFB4, TGFBR3, TPMT (2 SNPs), (P<0.05 or borderline significant for all three methods, 14 SNPs in total). In step two, these 14 SNPs were genotyped in additional 9 samples and the results combined with the genotyping results from the first step. For 7 of the 14 SNPs, the results are still significant/borderline significant by all three methods: ANOVA, QMIS and KW analysis strengthening our hypothesis that they are associated with the clearance of docetaxel.

ERCC1 protein expression predicts the response of cisplatin-based neoadjuvant chemotherapy in non-small-cell lung cancer

The excision repair cross-complementation group 1 (ERCC1) and BRCA1 have been identified as predictors of clinical outcomes among patients with non-small-cell lung cancer (NSCLC) treated with cisplatin-based chemotherapy. In this study, we immunohistochemically examined the ERCC1 and BRCA1 protein expression levels in 35 patients with metastatic mediastinal lymph nodes obtained prior to treatment as retrospective study. These patients had been enrolled in our studies on neoadjuvant chemotherapy with cisplatin and irinotecan (15 patients) or chemoradiotherapy with cisplatin and docetaxel plus concurrent thoracic radiation (20 patients). The relations between the ERCC1 or BRCA1 protein expression and the clinical outcomes of the patients were then examined. The rates of radiological response and pathological effectiveness were significantly higher among patients with ERCC1-negative tumors, compared with those with positive tumors in the neoadjuvant chemotherapy group (radiological response rates; 100% vs. 42.8%, P=0.013; pathological effectiveness; 100% vs. 47.1%, P=0.038), but no associations were observed in the neoadjuvant chemoradiotherapy group. Regarding survival, no significant differences in overall survival or disease-free survival were observed between patients with ERCC1-negative and positive tumors in both the neoadjuvant chemotherapy and chemoradiotherapy groups. In summary, we showed that a ERCC1-negative protein status was significantly related to tumor responsiveness to neoadjuvant chemotherapy with cisplatin and irinotecan, but such a status was not a clear prognostic predictor to cisplatin-based neoadjuvant therapy in NSCLC patients. Further study is needed to clarify the value of molecular predictors for customizing therapy for patients with NSCLC.

Targeting NF-kappaB in anticancer adjunctive chemotherapy

After more than three decades of its declaration, the war against cancer still appears far from being won. Although there have been decisive victories in a few battles, such as the one against testicular cancer, the overall result is sobering. Hopes for an imminent cure had been raised among the public by the promises of molecular biology, combinatorial chemistry and high-throughput screening. These promises have manifested themselves in the widely proclaimed strategy of rationally targeted anticancer drug discovery, which may be summarized as the 'one-gene-one target-one drug' approach. Over the years, however, it has gradually become clear that, in most cases, treatment of cancer with a single drug may at best delay progression of the disease but is unlikely to lead to a cure. Thus, it appears that rationally targeted monotherapy will have to be replaced by rationally targeted combination therapy. Inhibitors of NF-kappaB look likely to become an important weapon in the anticancer combination therapy arsenal.

Docetaxel and concurrent radiotherapy after two cycles of induction chemotherapy with cisplatin and vinorelbine in patients with locally advanced non-small-cell lung cancer. A phase II trial conducted by the Groupe Francais de Pneumo-Cancerologie (GFPC)

CONTEXT

The most satisfactory treatment for patients with locally advanced non-small-cell lung cancer (NSCLC) is combination chemotherapy-radiotherapy (CT-RT). The optimal treatment modalities remain to be determined.

OBJECTIVE

We conducted a multicenter phase II trial of the docetaxel-radiotherapy combination after induction chemotherapy with cisplatin-vinorelbine. The main endpoint was the objective response rate.

PATIENTS AND METHODS

Patient with inoperable stage locally advanced NSCLC received induction chemotherapy consisting of two cycles of cisplatin 100 mg/m2 on D1 and vinorelbine 25 mg/m2 on D1, D8, D15 and D22. Patients with responses or stable disease then received concurrent RT-CT consisting of 25 mg/m2/week docetaxel and single-fraction radiotherapy (66 grays (Gy) in 33 fractions) over 6.5 weeks.

RESULTS

Fifty-six patients were enrolled from 1 July 2000 to 31 December 2001. Sixteen patients left the trial after induction chemotherapy, eight for progression, five for toxicity, and two for intercurrent events. One patient underwent surgery after induction chemotherapy. In total, 40 of the 56 patients received RT-CT. Twelve (30%) of these 40 patients experienced grade III or IV pulmonary or esophageal toxicity. In the intention-to-treat analysis, the objective response rate was 46.4% (95% CI 33.0-60.2). The median time to progression was 6.2 months [1.1-26.0]. The median survival time was 13 months [0.3-44.9 months]. Nine patients progressed during RT-CT, six with brain metastases.

CONCLUSION

Weekly docetaxel with concurrent radiotherapy, following chemotherapy is acceptable. The tumor response rate is moderate. Further trials are required to determine the risk-benefit relationship of this treatment schedule, and the possible benefit of adding other cytotoxic drugs.

Camptothecin: current perspectives

This review provides a detailed discussion of recent advances in the medicinal chemistry of camptothecin, a potent antitumor antibiotic. Two camptothecin analogues are presently approved for use in the clinic as antitumor agents and several others are in clinical trials. Camptothecin possesses a novel mechanism of action involving the inhibition of DNA relaxation by DNA topoisomerase I, and more specifically the stabilization of a covalent binary complex formed between topoisomerase I and DNA. This review summarizes the current status of studies of the mechanism of action of camptothecin, including topoisomerase I inhibition and additional cellular responses. Modern synthetic approaches to camptothecin and several of the semi-synthetic methods are also discussed. Finally, a systematic evaluation of novel and important analogues of camptothecin and their contribution to the current structure-activity profile are considered.

Preoperative concurrent chemoradiotherapy with cisplatin and docetaxel in patients with locally advanced non-small-cell lung cancer

The objective of this study was to assess the feasibility and effectiveness of an induction chemoradiotherapy regimen followed by surgery in patients with locally advanced non-small-cell lung cancer (LA-NSCLC). A total of 22 patients with LA-NSCLC were treated with induction chemoradiotherapy consisting of cisplatin (40 mg m⁻²) and docetaxel (40 mg m⁻²) given on days 1, 8, 29 and 36 plus concurrent thoracic irradiation at a dose of 40–60 Gy (2 Gy fraction⁻¹ day⁻¹). Surgical resection was performed within 6 weeks after completion of induction therapy. Objective response to the induction therapy was obtained in 16 patients (73%). In all, 20 patients (91%) underwent surgery and complete resection was achieved in 19 patients (86%). Pathological downstaging and pathological complete response were obtained in 14 (64%) and five (23%) patients, respectively. With a median follow-up period of 32 months, the calculated 3-year overall and progression-free survival rates were 66 and 61%, respectively. It is noteworthy that the 3-year overall survival rate in 14 patients achieving pathological downstaging was extremely high (93%). Toxicity was manageable with standard approaches. No treatment-related deaths occurred. This combined modality treatment is feasible and highly effective in patients with LA-NSCLC. The results warrant further large-scale study to confirm the effectiveness of this regimen.

Defective stress kinase and Bak activation in response to ionizing radiation but not cisplatin in a non-small cell lung carcinoma cell line

We have here examined ionizing radiation (IR)-induced apoptotic signaling in one IR-sensitive small cell lung carcinoma (SCLC) and one resistant non-small cell lung carcinoma (NSCLC) cell line, both harboring mutant p53. In the sensitive SCLC cell line, IR induced conformational modulation of Bak and Bax, mitochondrial depolarization, and nuclear fragmentation. These events were not observed in the IR-resistant NSCLC cell line. However, in the same cells, cisplatin, a DNA-damaging drug, induced Bak and Bax modulation, mitochondrial depolarization, and nuclear fragmentation. Pre-mitochondrial signaling events were examined in order to further characterize the differing IR response. In the SCLC cell line, IR-induced apoptotic signaling was found to involve a MEKK1-related pathway and activation of the stress-activated kinases JNK and p38. In comparison, the NSCLC cell line had higher basal levels of activity of JNK and p38, and IR treatment did not further activate these kinases. However, NSCLC cells were sensitive to Bak modulation and apoptosis induced by a kinase-active mutant of MEKK1. Together, the results delineate a mechanism of IR resistance in NSCLC cells and indicate that IR and cisplatin induce Bak modulation and apoptosis via different pathways.

Report from the Radiation Oncology Committee of the Southwest Oncology Group (SWOG)

To achieve the ultimate goal of cancer treatment, which is 100% cancer control with negligible toxicity, the therapeutic window must be enlarged, allowing for higher doses of beneficial treatments with reduced toxicity. The advent of image- and metabolism-guided therapy offers the best opportunity to date for combining modern radiation targeting and imaging techniques. Indeed, for the first time, it is reasonable to locally target metastatic disease with the goal of sterilization. Combining these focal radiation techniques with novel targeted antiproliferative agents and full-dose classic cytotoxic chemotherapy will become more effective as we learn to use these compounds in a less systemically toxic manner and as radiation fields become more defined. In addition, increasing numbers of biologic modifiers of normal tissue response are becoming available, and they suggest great promise for decreasing the normal tissue toxicity resulting from both radiation and chemotherapy treatments. Thus, radiation metastectomy for gross metastases, used together with systemic control of micrometastatic disease, may yield improved survival rates. This hypothesis is ready for testing in cancers of the breast, prostate, colon, and in sarcomas. Enlarging the therapeutic window is a major goal that would allow for an increasingly favorable therapeutic gain.

Phase I/II study of concurrent twice-weekly paclitaxel and weekly cisplatin with radiation therapy for stage III non-small cell lung cancer

The optimal chemoradiation regimen for stage III non-small cell lung cancer (NSCLC) has not been determined. In this phase I/II study, the use of twice-weekly paclitaxel concomitant with weekly cisplatin and thoracic radiotherapy (RT) was evaluated. Patients with stage III NSCLC (without pleural effusion or cervical lymphadenopathy) were treated with thoracic RT (60 Gy in 30 fractions over 6 weeks) with concurrent weekly cisplatin 20 mg/m(2) and escalating doses of twice-weekly paclitaxel (starting dose of paclitaxel of 20 mg/m(2) increased in increments of 5 mg/m(2)) in successive cohorts of three to six patients until two or more patients experienced dose limiting toxicities (DLTs) at a particular dose level. All patients were planned to be given a further two cycles of consolidation chemotherapy consisting of paclitaxel 175 mg/m(2) and carboplatin AUC 5 after completion of RT. Twenty-five patients were enrolled in this study from two institutions. At a dose of paclitaxel 35 mg/m(2), two of four treated patients had DLTs (1 grade 3 oesophagitis and pulmonary toxicity; 1 grade 3 oesophagitis and infection). The recommended dose was therefore determined to be 30 mg/m(2) and a total of 15 patients were enrolled in an expanded cohort at this level. The overall response rate for all patients was 64% (95% CI: 43-82%). The estimated median survival was 23.6 months with an estimated 1-year and 2-year survival of 72 and 49%, respectively. Paclitaxel can be safely given twice-weekly at a dose of 30 mg/m(2) in combination with weekly cisplatin (20 mg/m(2)) and thoracic RT (60 Gy), and this regimen has significant activity in stage III NSCLC.