Targeted agents in non-small cell lung cancer (NSCLC): Clinical developments and rationale for the combination with thoracic radiotherapy

Emerging roles of PHLPP phosphatases in lung cancer

Pleckstrin homologous domain leucine-rich repeating protein phosphatases (PHLPPs) were originally identified as protein kinase B (Akt) kinase hydrophobic motif specific phosphatases to maintain the cellular homeostasis. With the continuous expansion of PHLPPs research, imbalanced-PHLPPs were mainly found as a tumor suppressor gene of a variety of solid tumors. In this review, we simply described the history and structures of PHLPPs and summarized the recent achievements in emerging roles of PHLPPs in lung cancer by 1) the signaling pathways affected by PHLPPs including Phosphoinositide 3-kinase (PI3K)/AKT, RAS/RAF/mitogen-activated protein kinase (MEK)/extracellular signal-regulated kinase (ERK) and Protein kinase C (PKC) signaling cascades. 2) function of PHLPPs regulatory factor USP46 and miR-190/miR-215, 3) the potential roles of PHLPPs in disease prognosis, Epidermal growth factor receptors (EGFR)- tyrosine kinase inhibitor (TKI) resistance and DNA damage, 4) and the possible function of PHLPPs in radiotherapy, ferroptosis and inflammation response. Therefore, PHLPPs can be considered as either biomarker or prognostic marker for lung cancer treatment.

Overexpressed RBPMS-AS1 increased cell radiosensitivity by sponging miR-19a-3p in lung cancer cell lines (A549 and SK-MES-1) via regulating PTEN/AKT axis

PURPOSE

This paper intended to study RBPMS-AS1 in lung cancer (LC) radiosensitivity.

MATERIALS AND METHODS

LC cells were transfected with RBPMS-AS1 overexpression plasmid and miR-19a-3p mimic and treated with radiation. PTEN, AKT, p-AKT, RBPMS-AS1, and miR-19a-3p expressions were detected via Western blot and qRT-PCR. The localization of RBPMS-AS1 in cells was determined through fluorescence in situ hybridization assay. The targeting relationships of RBPMS-AS1 and miR-19a-3p/miR-19a-3p and PTEN were determined through RIP and dual luciferase reporter analysis. Cell survival, viability, and apoptosis were assessed through colony formation, CCK-8, and flow-cytometry assays.

RESULTS

RBPMS-AS1 was downregulated in LC and mainly distributed in cytoplasm. RBPMS-AS1 targeted miR-19a-3p in LC cells. Radiation suppressed LC cell survival, viability, and induced apoptosis, as overexpressed RBPMS-AS1 performed the similar effects and enhanced those effects induced by radiation. MiR-19a-3p mimic reversed the effect of overexpressed RBPMS-AS1 on enhancing radiation-induced LC cell apoptosis. MiR-19a-3p targeted PTEN and miR-19a-3p mimic reversed the effect of overexpressed RBPMS-AS1 on PTEN and phosphorylation of AKT in LC cells.

CONCLUSION

Overexpressed RBPMS-AS1 sponged miR-19a-3p to increase cell radiosensitivity in LC via regulating PTEN/AKT axis.

Review: Mechanisms and perspective treatment of radioresistance in non-small cell lung cancer

Radiotherapy is the major treatment of non-small cell lung cancer (NSCLC). The radioresistance and toxicity are the main obstacles that leading to therapeutic failure and poor prognosis. Oncogenic mutation, cancer stem cells (CSCs), tumor hypoxia, DNA damage repair, epithelial-mesenchymal transition (EMT), and tumor microenvironment (TME) may dominate the occurrence of radioresistance at different stages of radiotherapy. Chemotherapy drugs, targeted drugs, and immune checkpoint inhibitors are combined with radiotherapy to treat NSCLC to improve the efficacy. This article reviews the potential mechanism of radioresistance in NSCLC, and discusses the current drug research to overcome radioresistance and the advantages of Traditional Chinese medicine (TCM) in improving the efficacy and reducing the toxicity of radiotherapy.

Targeting the DNA Damage Response Machinery for Lung Cancer Treatment

Lung cancer is considered the most commonly diagnosed cancer and one of the leading causes of death globally. Despite the responses from small-cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC) patients to conventional chemo- and radiotherapies, the current outcomes are not satisfactory. Recently, novel advances in DNA sequencing technologies have started to take off which have provided promising tools for studying different tumors for systematic mutation discovery. To date, a limited number of DDR inhibition trials have been conducted for the treatment of SCLC and NSCLC patients. However, strategies to test different DDR inhibitor combinations or to target multiple pathways are yet to be explored. With the various biomarkers that have either been recently discovered or are the subject of ongoing investigations, it is hoped that future trials would be designed to allow for studying targeted treatments in a biomarker-enriched population, which is defensible for the improvement of prognosis for SCLC and NSCLC patients. This review article sheds light on the different DNA repair pathways and some of the inhibitors targeting the proteins involved in the DNA damage response (DDR) machinery, such as ataxia telangiectasia and Rad3-related protein (ATR), DNA-dependent protein kinase (DNA-PK), and poly-ADP-ribose polymerase (PARP). In addition, the current status of DDR inhibitors in clinical settings and future perspectives are discussed.

Genome-wide CRISPR/Cas9 screening identifies CARHSP1 responsible for radiation resistance in glioblastoma

Glioblastomas (GBM) is the most common primary malignant brain tumor, and radiotherapy plays a critical role in its therapeutic management. Unfortunately, the development of radioresistance is universal. Here, we identified calcium-regulated heat-stable protein 1 (CARHSP1) as a critical driver for radioresistance utilizing genome-wide CRISPR activation screening. This is a protein with a cold-shock domain (CSD)-containing that is highly similar to cold-shock proteins. CARHSP1 mRNA level was upregulated in irradiation-resistant GBM cells and knockdown of CARHSP1 sensitized GBM cells to radiotherapy. The high expression of CARHSP1 upon radiation might mediate radioresistance by activating the inflammatory signaling pathway. More importantly, patients with high levels of CARHSP1 had poorer survival when treated with radiotherapy. Collectively, our findings suggested that targeting the CARHSP1/TNF-α inflammatory signaling activation induced by radiotherapy might directly affect radioresistance and present an attractive therapeutic target for GBM, particularly for patients with high levels of CARHSP1.

Phase I trial of the MEK inhibitor selumetinib in combination with thoracic radiotherapy in non-small cell lung cancer

Background

The RAS/RAF/MEK/ERK signalling pathway has a pivotal role in cancer proliferation and modulating treatment response. Selumetinib inhibits MEK and enhances effects of radiotherapy in preclinical studies.

Patients and methods

Single-arm, single-centre, open-label phase I trial. Patients with stage III NSCLC unsuitable for concurrent chemo-radiotherapy, or stage IV with dominant thoracic symptoms, were recruited to a dose-finding stage (Fibonacci 3 + 3 design; maximum number = 18) then an expanded cohort (n = 15). Oral selumetinib was administered twice daily (starting dose 50 mg) commencing 7 days prior to thoracic radiotherapy, then with radiotherapy (6-6.5 weeks; 60-66 Gy/30-33 fractions). The primary objective was to determine the recommended phase II dose (RP2D) of selumetinib in combination with thoracic radiotherapy.

Results

21 patients were enrolled (06/2010-02/2015). Median age: 62y (range 50-73). M:F ratio 12(57%):9(43%). ECOG PS 0:1, 7(33%):14(67%). Stage III 16(76%); IV 5(24%). Median GTV 64 cm³ (range 1-224 cm³). 15 patients comprised the expanded cohort at starting dose. All 21 patients completed thoracic radiotherapy as planned and received induction chemotherapy. 13 (62%) patients received the full dose of selumetinib.In the starting cohort no enhanced radiotherapy-related toxicity was seen. Two patients had dose-limiting toxicity (1x grade 3 diarrhoea/fatigue and 1x pulmonary embolism). Commonest grade 3-4 adverse events: lymphopaenia (19/21 patients) and hypertension (7/21 patients). One patient developed grade 3 oesophagitis. No patients developed grade ≥3 radiation pneumonitis. Two patients were alive at the time of analysis (24 and 26 months follow-up, respectively). Main cause of first disease progression: distant metastases ± locoregional progression (12/21 [57.1%] patients). Six patients had confirmed/suspected pneumocystis jiroveci pneumonia.

Conclusion

We report poor outcome and severe lymphopenia in most patients treated with thoracic radiotherapy and selumetinib at RP2D in combination, contributing to confirmed/clinically suspected pneumocystis jiroveci pneumonia. These results suggest that this combination should not be pursued in a phase II trial.ClinicalTrials.gov reference: NCT01146756.

Circulating Exosomal miR-96 as a Novel Biomarker for Radioresistant Non-Small-Cell Lung Cancer

Patients with non-small-cell lung cancer (NSCLC) frequently develop radioresistance, resulting in poor response to radiation and unfavourable prognosis. Early detection of radioresistance hence can guide the adjustment of treatment regimens in time. Exosomes are lipid bilayer-enclosed vesicles with sub-micrometer size that are released by various cells. Exosomes contain a tissue-specific signature wherein a variety of proteins and nucleic acids are selectively packaged. Growing evidence shows exosomes are involved in cancer pathophysiology and exosomes as the latest addition to the liquid biopsy portfolio have been used in cancer diagnosis. Compared to cell free RNA, exosomal lipid envelope can effectively protect RNA cargo against degradation. Therefore, exosomes may hold great promise for the identification of radioresistance. Here, we report six plasma exosomal miRNAs could be used to distinguish radioresistant NSCLC patients from radiosensitive NSCLC patients and to evaluate the prognosis of NSCLC. Samples were obtained from 52 NSCLC patients with or without radioresistance and 45 age-matched healthy volunteers. Exosomes in 1 ml plasma were isolated followed by extraction of small RNA. The expression levels of miRNAs were determined by quantitative real-time PCR. Potential miRNA markers were further evaluated in additional 52 NSCLC patients. We found exosomal miR-1246 and miR-96 are significantly overexpressed in NSCLC patients. Moreover, exosomal miR-96 in patients with radioresistant NSCLC is significantly higher than that of controls. Exosomal miR-96 also demonstrates a significant correlation with vascular invasion and poor overall survival. Altogether, our results indicate that exosomal miR-96 could be a non-invasive diagnostic and prognostic marker of radioresistant NSCLC.

Characteristics and Predictors of Radiographic Local Failure in Patients With Spinal Metastases Treated With Palliative Conventional Radiation Therapy

Purpose

Although local control is an important issue for longer-term survivors of spinal metastases treated with conventional external beam radiation therapy (EBRT), the literature on radiographic local failure (LF) in these patients is sparse. To inform clinical decision-making, we evaluated rates, consequences, and predictors of radiographic LF in patients with spinal metastases managed with palliative conventional EBRT alone.

Methods and Materials

We retrospectively reviewed 296 patients with spinal metastases who received palliative EBRT at a single institution (2006-2013). Radiographic LF was defined as radiologic progression within the treatment field, with death considered a competing risk. Kaplan-Meier, cumulative incidence, and Cox regression analyses determined overall survival estimates, LF rates, and predictors of LF, respectively.

Results

There were 182 patients with follow-up computed tomography or magnetic resonance imaging; median overall survival for these patients was 7.7 months. Patients received a median of 30 Gy in 10 fractions to a median of 4 vertebral bodies. Overall, 74 of 182 patients (40.7%) experienced LF. The 6-, 12-, and 18-month LF rates were 26.5%, 33.1%, and 36.5%, respectively, while corresponding rates of death were 24.3%, 38.1%, and 45.9%. Median time to LF was 3.8 months. Of those with LF, 51.4% had new compression fractures, 39.2% were admitted for pain control, and 35.1% received reirradiation; median time from radiation therapy (RT) to each of these events was 3.0, 5.7, and 9.2 months, respectively. Independent predictors of LF included single-fraction RT (8 Gy) (hazard ratio [HR], 2.592; 95% confidence interval [CI], 1.437-4.675; P = .002), lung histology (HR, 3.568; 95% CI, 1.532-8.309; P = .003), and kidney histology (HR, 4.937; 95% CI, 1.529-15.935; P = .008).

Conclusions

Patients experienced a >30% rate of radiographic LF by 1 year after EBRT. Single-fraction RT and lung or kidney histology predicted LF. Given the high rates of LF for patients with favorable prognosis, assessing the risk of death versus LF is important for clinical decision-making.

miR‑7/SP1/TP53BP1 axis may play a pivotal role in NSCLC radiosensitivity

MicroRNA‑7 (miR‑7) has been identified as a tumor suppressor in non‑small cell lung cancer (NSCLC) and a radiosensitivity regulator. Numerous studies have revealed that specific protein 1 (SP1) plays a critical role in the tumorigenesis of various types of cancers and regulates radiosensitivity and tumor suppressor p53‑binding protein 1 (TP53BP1), which plays an essential role in DNA repair. However, it is not clear whether miR‑7 has a regulatory effect on SP1 and TP53BP1 in NSCLC. In the present study it was revealed that miR‑7 directly binds to the 3'UTR of SP1, thereby suppressing SP1 expression to regulate radiosensitivity. Overexpression of miR‑7 and SP1 and knockdown of miR‑7 and SP1 were performed using lentiviral transfection. Protein and mRNA abundance of SP1 and TP53BP1 were determined using western blotting and RT‑qPCR, respectively, while miR‑7 binding to SP1 was validated using a luciferase reporter assay. Biological function analysis indicated that miR‑7 negatively regulated SP1 and inhibited cell proliferation, migration, and invasion when combined with radiation. It was also revealed that the expression of TP53BP1 was positively regulated by SP1 or negatively regulated by miR‑7. In conclusion, SP1 was a target of miR‑7, and the decreased expression of SP1 resulting from miR‑7 overexpression in NSCLC was vital for improving radiosensitivity in NSCLC cells. Moreover, SP1 expression was detected in 95 paired NSCLC and adjacent normal tissues, and it was determined that SP1 was significantly upregulated in NSCLC tissues and that its upregulation was correlated with the degree of tissue differentiation. Thus, SP1 and/or miR‑7 may be potential molecular targets in NSCLC radiotherapy.

IQGAP3 interacts with Rad17 to recruit the Mre11-Rad50-Nbs1 complex and contributes to radioresistance in lung cancer

IQ motif containing GTPase-activating protein 3 (IQGAP3) has been implicated in diverse cellular processes, including neuronal morphogenesis, cell proliferation and motility, and epithelial-mesenchymal transition. However, its role in cancer radioresistance is completely unknown. Here, we report that IQGAP3 is overproduced in lung cancer patients and correlates with poor clinical outcomes. Functionally, we demonstrate that depletion of IQGAP3 impairs oncogenesis and overcomes radioresistance in lung cancer in vitro and in vivo. Mechanistically, we uncover that IQGAP3 interacts with Rad17 and controls its expression to activate the ATM/Chk2 and ATR/Chk1 signaling pathways by recruiting the Mre11-Rad50-Nbs1 (MRN) complex in response to DNA damage. Moreover, Rad17 is identified as the major downstream effector that mediates the functions of IQGAP3 in lung cancer. Clinically, IQGAP3 overexpression positively correlates with Rad17 upregulation in human lung cancer tissues. Collectively, these data support key role for IQGAP3 in promoting lung cancer radioresistance by interacting with Rad17 and suggest that targeting IQGAP3 may be an attractive strategy for lung cancer radiotherapy.

Anti-tumor efficacy of CKD-516 in combination with radiation in xenograft mouse model of lung squamous cell carcinoma

BACKGROUND

Hypoxic tumors are known to be highly resistant to radiotherapy and cause poor prognosis in non-small cell lung cancer (NSCLC) patients. CKD-516, a novel vascular disrupting agent (VDA), mainly affects blood vessels in the central area of the tumor and blocks tubulin polymerization, thereby destroying the aberrant tumor vasculature with a rapid decrease in blood, resulting in rapid tumor cell death. Therefore, we evaluated the anti-tumor efficacy of CKD-516 in combination with irradiation (IR) and examined tumor necrosis, delayed tumor growth, and expression of proteins involved in hypoxia and angiogenesis in this study.

METHODS

A xenograft mouse model of lung squamous cell carcinoma was established, and the tumor was exposed to IR 5 days per week. CKD-516 was administered with two treatment schedules (day 1 or days 1 and 5) 1 h after IR. After treatment, tumor tissues were stained with hematoxylin and eosin, and pimonidazole. HIF-1α, Glut-1, VEGF, CD31, and Ki-67 expression levels were evaluated using immunohistochemical staining.

RESULTS

Short-term treatment with IR alone and CKD-516 + IR (d1) significantly reduced tumor volume (p = 0.006 and p = 0.048, respectively). Treatment with CKD-516 + IR (d1 and d1, 5) resulted in a marked reduction in the number of blood vessels (p < 0.005). More specifically, CKD-516 + IR (d1) caused the most extensive tumor necrosis, which resulted in a significantly large hypoxic area (p = 0.02) and decreased HIF-1α, Glut-1, VEGF, and Ki-67 expression. Long-term administration of CKD-516 + IR reduced tumor volume and delayed tumor growth. This combination also greatly reduced the number of blood vessels (p = 0.0006) and significantly enhanced tumor necrosis (p = 0.004). CKD-516 + IR significantly increased HIF-1α expression (p = 0.0047), but significantly reduced VEGF expression (p = 0.0046).

CONCLUSIONS

Taken together, our data show that when used in combination, CKD-516 and IR can significantly enhance anti-tumor efficacy compared to monotherapy in lung cancer xenograft mice.

Long non-coding RNA CASC2 enhances irradiation-induced endoplasmic reticulum stress in NSCLC cells through PERK signaling

Radiotherapy is instrumental in the treatment of inoperable non-small cell lung cancer (NSCLC). Studies have revealed that radiotherapy induces endoplasmic reticulum (ER) stress, which consequently induces apoptosis and sensitization of cancer cells. A recent study has revealed that long non-coding RNA (lncRNA) CASC2 is negatively correlated with the malignancy of NSCLC cells. The present study investigated the effects and molecular mechanisms of CASC2 on radiosensitivity and ER stress in NSCLC cells. The overexpression of CASC2 markedly decreased cell survival and increased apoptosis, expression of PERK, phosphorylated-eIF2α and CHOP in irradiated human NSCLC cells, whereas knocking down PERK reversed these effects. Moreover, CASC2 considerably promoted the stability of PERK mRNA, but had no effect on the activity of PERK gene promoter in irradiated NSCLC cells. Strikingly, CASC2 exhibited no apparent effect on non-irradiated NSCLC cells. This study demonstrated that lncRNA CASC2 increases the stability of PERK mRNA, which consequently triggers the PERK/eIF2α/CHOP ER stress pathway and promotes radiosensitivity or apoptosis in irradiated NSCLC cells. Results of the present study suggest that CASC2 can act as an effective therapeutic target to enhance the efficacy of radiotherapy in the treatment of NSCLC.

Antitumor, Inhibition of Metastasis and Radiosensitizing Effects of Total Nutrition Formula on Lewis Tumor-Bearing Mice

Non-small-cell lung cancer (NSCLC) causes high mortality. Radiotherapy is an induction regimen generally applied to patients with NSCLC. In view of therapeutic efficacy, the outcome is not appealing in addition to bringing about unwanted side effects. Total nutrition is a new trend in cancer therapy, which benefits cancer patients under radiotherapy. Male C57BL/6JNarl mice were experimentally divided into five groups: one control group, one T group (borne with Lewis lung carcinoma but no treatment), and three Lewis lung carcinoma-bearing groups administrated with a total nutrition formula (T + TNuF group), a local radiotherapy plus daily 3 Gy in three fractions (T + R group), or a combination TNuF and radiotherapy (T + R + TNuF group). These mice were assessed for their mean tumor volumes, cachectic symptoms and tumor metastasis. TNuF administration significantly suppressed tumor growth and activated apoptotic cell death in NSCLC-bearing mice under radiation. The body-weight gain was increased, while the radiation-induced cachexia was alleviated. Analysis of mechanisms suggests that TNuF downregulates EGFR and VEGF signaling pathways, inhibiting angiogenesis and metastasis. In light of radiation-induced tumor cell death, mitigation of radiation-induced cachexia and inhibition of tumor cell distant metastasis, the combination of TNuF and radiotherapy synergistically downregulates EGFR and VEGF signaling in NSCLC-bearing mice.

Extracellular signal-regulated kinase 5 increases radioresistance of lung cancer cells by enhancing the DNA damage response

Radiotherapy is a frequent mode of cancer treatment, although the development of radioresistance limits its effectiveness. Extensive investigations indicate the diversity of the mechanisms underlying radioresistance. Here, we aimed to explore the effects of extracellular signal-regulated kinase 5 (ERK5) on lung cancer radioresistance and the associated mechanisms. Our data showed that ERK5 is activated during solid lung cancer development, and ectopic expression of ERK5 promoted cell proliferation and G2/M cell cycle transition. In addition, we found that ERK5 is a potential regulator of radiosensitivity in lung cancer cells. Mechanistic investigations revealed that ERK5 could trigger IR-induced activation of Chk1, which has been implicated in DNA repair and cell cycle arrest in response to DNA double-strand breaks (DSBs). Subsequently, ERK5 knockdown or pharmacological inhibition selectively inhibited colony formation of lung cancer cells and enhanced IR-induced G2/M arrest and apoptosis. In vivo, ERK5 knockdown strongly radiosensitized A549 and LLC tumor xenografts to inhibition, with a higher apoptotic response and reduced tumor neovascularization. Taken together, our data indicate that ERK5 is a novel potential target for the treatment of lung cancer, and its expression might be used as a biomarker to predict radiosensitivity in NSCLC patients.

Resistance to radiotherapy in patients with lung cancer may be countered by targeting a protein involved in promoting DNA repair. Radiotherapy causes DNA double-stranded breaks in lung cancer cells in order to kill them. However, cancer cells can show improved DNA repair and responses to damage, resulting in resistance to treatment. Zi-Chun Hua, Hongqin Zhuang at Nanjing University in China and co-workers examined the activity of the extracellular signal-related kinase 5 (ERK5) protein in response to the stress of ionizing radiation. They found that after radiation exposure ERK5 increased expression of another protein involved in DNA repair, facilitating cancer cell recovery. Knocking out ERK5 suppressed this resistance to radiotherapy. ERK5 could be a valuable target for treating lung cancer, and ERK5 expression level could be used as a biomarker for patient sensitivity to radiotherapy.

Advances in targeting the transforming growth factor β1 signaling pathway in lung cancer radiotherapy

Lung cancer was demonstrated to be the most lethal type of malignant tumor amongst humans in the global cancer statistics of 2012. As one of the primary treatments, radiotherapy has been reported to induce remission in, and even cure, patients with lung cancer. However, the side effects of radiotherapy may prove lethal in certain patients. In past decades, the transforming growth factor β1 (TGFB1) signaling pathway has been revealed to serve multiple functions in the control of lung cancer progression and the radiotherapy response. In mammals, this signaling pathway is initiated through activation of the TGFB1 receptor complex, which signals via cytoplasmic SMAD proteins or other downstream signaling pathways. Multiple studies have demonstrated that TGFB1 serves important functions in lung cancer radiotherapy. The present study summarized and reviewed recent progress in elucidating the function of the TGFB1 signaling pathway in predicting radiation pneumonitis, as well as current strategies for targeting the TGFB1 signaling pathway in lung cancer radiotherapy, which may provide potential targets for lung cancer therapy.

European Organization for Research and Treatment of Cancer (EORTC) recommendations for planning and delivery of high-dose, high precision radiotherapy for lung cancer

PURPOSE

To update literature-based recommendations for techniques used in high-precision thoracic radiotherapy for lung cancer, in both routine practice and clinical trials.

METHODS

A literature search was performed to identify published articles that were considered clinically relevant and practical to use. Recommendations were categorised under the following headings: patient positioning and immobilisation, Tumour and nodal changes, CT and FDG-PET imaging, target volumes definition, radiotherapy treatment planning and treatment delivery. An adapted grading of evidence from the Infectious Disease Society of America, and for models the TRIPOD criteria, were used.

RESULTS

Recommendations were identified for each of the above categories.

CONCLUSION

Recommendations for the clinical implementation of high-precision conformal radiotherapy and stereotactic body radiotherapy for lung tumours were identified from the literature. Techniques that were considered investigational at present are highlighted.

Evaluation of concurrent chemoradiotherapy for locally advanced NSCLC according to EGFR mutation status

Concurrent chemoradiotherapy (cCRT) is the standard treatment for patients with locally advanced non-small cell lung cancer (LA-NSCLC). However, the efficacy and safety of this treatment has not been compared between patients who possess epidermal growth factor receptor (EGFR) mutations and patients with wild-type EGFR. The objective of the present study was to evaluate the effect of the presence of EGFR gene mutations in patients with LA-NSCLC receiving cCRT. Between January 2007 and December 2013, the records of 64 patients were reviewed retrospectively. The data were statistically analyzed to evaluate the efficacy of cCRT according to EGFR mutation status. In total, 15/64 were revealed to possess EGFR mutations, 23%, and comprised the mutant EGFR group. The progression-free survival time was significantly shorter in the mutant EGFR group compared with the patient group with tumors exhibiting wild-type EGFR, 6.3 and 9.5 months, respectively (P<0.001). The overall survival rate was longer in the mutant EGFR group compared with the wild-type EGFR group, although the difference was not statistically significant, 37.1 and 21.1 months, respectively (P=0.26). The disease recurred in all of the patients of the mutant EGFR group, whilst the recurrence rate in the wild-type EGFR group was 89%. The frequency of distant metastasis was significantly higher in the mutant EGFR group compared with the wild-type EGFR group. In conclusion, these data suggest that additional studies are required to identify strategies for reinforcing the efficacy of cCRT, with a focus on the potential use of EGFR tyrosine kinase inhibitors for patients exhibiting an EGFR mutation.

Intracellular calcium promotes radioresistance of non-small cell lung cancer A549 cells through activating Akt signaling

Radiotherapy is a major therapeutic approach in non-small cell lung cancer but is restricted by radioresistance. Although Akt signaling promotes radioresistance in non-small cell lung cancer, it is not well understood how Akt signaling is activated. Since intracellular calcium (Ca²⁺) could activate Akt in A549 cells, we investigated the relationship between intracellular calcium (Ca²⁺) and Akt signaling in radioresistant A549 cells by establishing radioresistant non-small cell lung cancer A549 cells. The radioresistant cell line A549 was generated by dose-gradient irradiation of the parental A549 cells. The cell viability, proliferation, and apoptosis were, respectively, assessed using the cell counting kit-8, EdU labeling, and flow cytometry analysis. The phosphorylation of Akt was evaluated by Western blotting, and the intracellular Ca²⁺ concentration was assessed by Fluo 4-AM. The radioresistant A549 cells displayed mesenchymal morphology. After additional irradiation, the radioresistant A549 cells showed decreased cell viability and proliferation but increased apoptosis. Moreover, the intracellular Ca²⁺ concentration and the phosphorylation level on the Akt473 site in radioresistant A549 cells were higher than those in original cells, whereas the percentage of apoptosis in radioresistant A549 cells was less. All these results could be reversed by verapamil. In conclusion, our study found that intracellular Ca²⁺ could promote radioresistance of non-small cell lung cancer cells through phosphorylating of Akt on the 473 site, which contributes to a better understanding on the non-small cell lung cancer radioresistance, and may provide a new target for radioresistance management.

Antagonism of EGFR and Notch limits resistance to EGFR inhibitors and radiation by decreasing tumor-initiating cell frequency

Epidermal growth factor receptor (EGFR) blockade and radiation are efficacious in the treatment of cancer, but resistance is commonly reported. Studies have suggested that dysregulation of Notch signaling and enrichment of the cancer stem cell population underlie these treatment challenges. Our data show that dual targeting of EGFR and Notch2/3 receptors with antibody CT16 not only inhibited signaling mediated by these receptors but also showed a strong anti-stem cell effect both in vitro and in vivo. Treatment with CT16 prevented acquired resistance to EGFR inhibitors and radiation in non-small cell lung cancer (NSCLC) cell line models and patient-derived xenograft tumors. CT16 also had a superior radiosensitizing impact compared with EGFR inhibitors. CT16 in combination with radiation had a larger antitumor effect than the combination of radiation with EGFR inhibitors or tarextumab. Mechanistically, CT16 treatment inhibits the stem cell-like subpopulation, which has a high mesenchymal gene expression and DNA repair activity, and reduces tumor-initiating cell frequency. This finding highlights the capacity of a combined blockade of EGFR and Notch signaling to augment the response to radiation and suggests that CT16 may achieve clinical efficacy when combined with radiation in NSCLC treatment.

ANTITUMOR AND APOPTOTIC EFFECTS OF CUCURBITACIN A IN A-549 LUNG CARCINOMA CELLS IS MEDIATED VIA G2/M CELL CYCLE ARREST AND M-TOR/PI3K/AKT SIGNALLING PATHWAY

Background:

The main aim of this study was to demonstrate the antitumor potential of cucurbitacin A on A-549 NSCLC (non-small cell lung cancer cells). The effects of Cucurbitacin A on apoptotic induction, cell physic, cell cycle failure and m-TOR/PI3K/Akt signalling pathway were also investigated in the present study.

Materials and Methods:

MTT assay and clonogenic assay were carried out to study effects of this compound on cell cytotoxicity and colony forming tendency in A-549 cells. Moreover, phase and fluorescence microscopic techniques were used to examine the effects on cell morphology and induction of apoptosis. The effects on cell cycle phase distribution were investigated by flow cytometry and effects on m-TOR/PI3K/Akt signalling proteins were assessed by western blot analysis.

Results:

Results showed that cucurbitacin A induced dose-dependent cytotoxic effects along with suppressing the colony forming tendency in these cells. Cucurbitacin A also induced morphological changes in these cells featuring chromatin condensation, cell shrinkage and apoptotic body formation. G2/M phase cell cycle collapse was also induced by Cucurbitacin A along with inhibition of expression levels of m-TOR/PI3K/Akt proteins.

Conclusions:

In conclusion, cucurbitacin A inhibits cancer growth in A-549 NSCLC cells by inducing apoptosis, targeting m-TOR/PI3K/Akt signalling pathway and G2/M cell cycle.

DANGER is involved in high glucose-induced radioresistance through inhibiting DAPK-mediated anoikis in non-small cell lung cancer

¹⁸F-labeled fluorodeoxyglucose (FDG) uptake during FDG positron emission tomography seems to reflect increased radioresistance. However, the exact molecular mechanism underlying high glucose (HG)-induced radioresistance is unclear. In the current study, we showed that ionizing radiation-induced activation of the MEK-ERK-DAPK-p53 signaling axis is required for anoikis (anchorage-dependent apoptosis) of non-small cell lung cancer (NSCLC) cells in normal glucose media. Phosphorylation of DAPK at Ser734 by ERK was essential for p53 transcriptional activity and radiosensitization. In HG media, overexpressed DANGER directly bound to the death domain of DAPK, thus inhibiting the catalytic activity of DAPK. In addition, inhibition of the DAPK-p53 signaling axis by DANGER promoted anoikis-resistance and epithelial-mesenchymal transition (EMT), resulting in radioresistance of HG-treated NSCLC cells. Notably, knockdown of DANGER enhanced anoikis, EMT inhibition, and radiosensitization in a mouse xenograft model of lung cancer. Taken together, our findings offered evidence that overexpression of DANGER and the subsequent inhibitory effect on DAPK kinase activity are critical responses that account for HG-induced radioresistance of NSCLC.

The Challenges Faced in Developing Novel Drug Radiation Combinations in Non-small Cell Lung Cancer

Lung cancer is the most common cancer diagnosed in the UK. Outcomes for patients with this disease remain poor and new strategies to treat this disease require investigation. One potential option is to combine novel agents with radiotherapy in clinical studies. Here we discuss some of the important issues to consider when combining novel agents with radiotherapy, together with potential solutions as discussed at a recent Clinical Translational Radiotherapy Group (CTRad) workshop.

DDB2 increases radioresistance of NSCLC cells by enhancing DNA damage responses

Radiotherapy resistance is one of the major factors limiting the efficacy of radiotherapy in lung cancer patients. The extensive investigations indicate the diversity in the mechanisms underlying radioresistance. Here, we revealed that DNA damage binding protein 2 (DDB2) is a potential regulator in the radiosensitivity of non-small cell lung cancer (NSCLC) cells. DDB2, originally identified as a DNA damage recognition factor in the nucleotide excision repair, promotes the survival and inhibits the apoptosis of NSCLC cell lines upon ionizing radiation (IR). Mechanistic investigations demonstrated that DDB2 is able to facilitate IR-induced phosphorylation of Chk1, which plays a critical role in the cell cycle arrest and DNA repair in response to IR-induced DNA double-strand breaks (DSBs). Indeed, knockdown of DDB2 compromised the G2 arrest in the p53-proficient A549 cell line and reduced the efficiency of homologous recombination (HR) repair. Taken together, our data indicate that the expression of DDB2 in NSCLC could be used as a biomarker to predict radiosensitivity of the patients. Targeting Chk1 can be used to increase the efficacy of radiotherapy in patients of NSCLC possessing high levels of DDB2.

Molecular targeted therapy to improve radiotherapeutic outcomes for non-small cell lung carcinoma

Effective treatments for non-small cell lung carcinoma (NSCLC) remain elusive. The use of concurrent chemotherapy with radiotherapy (RT) has improved outcomes, but a significant proportion of NSCLC patients are too frail to be able to tolerate an intense course of concurrent chemoradiotherapy. The development of targeted therapies ignited new hope in enhancing radiotherapeutic outcomes. The use of targeted therapies against the epidermal growth factor receptor (EGFR) has offered slight but significant benefits in concurrent use with RT for certain patients in certain situations. However, despite theoretical promise, the use of anti-angiogenics, such as bevacizumab and endostatin, has not proven clinically safe or useful in combination with RT. However, many new targeted agents against new targets are being experimented for combined use with RT. It is hoped that these agents may provide a significant breakthrough in the radiotherapeutic management of NSCLC. The current review provides a brief discussion about the targets, the targeted therapies, the rationale for the use of targeted therapies in combination with RT, and a brief review of the existing data on the subject.

Radiation-induced miR-208a increases the proliferation and radioresistance by targeting p21 in human lung cancer cells

BACKGROUND

Lung cancer has long been the most dangerous malignant tumor among males in both well developed and poorly developed countries. Radiotherapy plays a critical role in the curative management of inoperable non-small cell lung cancer (NSCLC) and is also used as a post-surgical treatment in lung cancer patients. Radioresistance is an important factor that limits the efficacy of radiotherapy for NSCLC patients. Increasing evidence suggests that microRNAs (miRNAs) possess diverse cellular regulatory roles in radiation responses.

METHODS

In this study, we used miRNA microarray technology to identify serum miRNAs that were differentially expressed before and after radiotherapy in lung cancer patients. We further examined the biological function of miR-208a on cell viability, apoptotic death and cell cycle distribution in human lung cancer cells and explored the probable mechanism.

RESULTS

Nine miRNAs, including miR-29b-3p, miR-200a-3p, and miR-126-3p were significantly down-regulated, whereas miR-208a was the only miRNA that was up-regulated in the serum of the patients after radiation treatment (P < 0.05). The expression of miR-208a could be induced by X-ray irradiation in lung cancer cells. Forced expression of miR-208a promoted cell proliferation and induced radioresistance via targeting p21 with a corresponding activation of the AKT/mTOR pathway in lung cancer cells, whereas down-regulation of miR-208a resulted in the opposite effects. In addition, down-regulation of miR-208a increased the percentage of cells undergoing apoptosis and inhibited the G1 phase arrest in NSCLC cells. Moreover, miR-208a from the serum exosome fraction of lung cancer patients could shuttle to A549 cells in a time-dependent manner, which was likely to contribute to the subsequent biological effects.

CONCLUSIONS

The present study provides evidence that miR-208a can affect the proliferation and radiosensitivity of human lung cancer cells by targeting p21 and can be transported by exosomes. Thus, miR-208a may serve as a potential therapeutic target for lung cancer patients.

Synergistic Antiproliferative Effects of a New Cucurbitacin B Derivative and Chemotherapy Drugs on Lung Cancer Cell Line A549

Nonsmall cell lung cancer (NSCLC) represents an important cause of mortality worldwide due to its aggressiveness and growing resistance to currently available therapy. Cucurbitacins have emerged as novel potential anticancer agents showing strong antiproliferative effects and can be promising candidates for combined treatments with clinically used anticancer agents. This study investigates the synergistic antiproliferative effects of a new semisynthetic derivative of cucurbitacin B (DACE) with three chemotherapy drugs: cisplatin (CIS), irinotecan (IRI), and paclitaxel (PAC) on A549 cells. The most effective combinations were selected for studies of the mechanism of action. Using an in silico tool, DACE seems to act by a different mechanism of action when compared with that of different classes of drugs already used in clinical settings. DACE also showed potent synergic effects with drugs, and the most potent combinations induced G2/M cell cycle arrest by modulating survivin and p53 expression, disruption of F-actin cytoskeleton, and cell death by apoptosis. These treatments completely inhibited the clonogenic potential and did not reduce the proliferation of nontumoral lung cells (MRC-5). DACE also showed relevant antimigratory and anti-invasive effects, and combined treatments modulated cell migration signaling pathways evolved with metastasis progression. The effects of DACE associated with drugs was potentiated by the oxidant agent l-buthionine-sulfoximine (BSO), and attenuated by N-acetilcysteine (NAC), an antioxidant agent. The antiproliferative effects induced by combined treatments were attenuated by a pan-caspase inhibitor, indicating that the effects of these treatments are dependent on caspase activity. Our data highlight the therapeutic potential of DACE used in combination with known chemotherapy drugs and offer important insights for the development of more effective and selective therapies against lung cancer.

Endostar enhances the antitumor effects of radiation by affecting energy metabolism and alleviating the tumor microenvironment in a Lewis lung carcinoma mouse model

Lung cancer is a leading cause of morbidity and mortality. Previous studies have identified that an improvement in treatment efficacy was achieved using Endostar; however, the role of Endostar in lung cancer remains poorly understood. The present study investigated whether the enhanced antitumor effects of Endostar in combination with radiation involved changes in the metabolism and microenvironment in non-small cell lung cancer. A Lewis lung carcinoma mouse model was used, including the control, Endostar (ES), radiotherapy (RT) and Endostar plus radiotherapy (ES + RT) groups. The tumor inhibition rates and growth were described based on changes in tumor volume. In addition, ultraviolet enzymatic analysis was performed to determine the lactate level and reverse transcription-polymerase chain reaction was used to measure the mRNA expression of lactate dehydrogenase (LDH). A Meph-3 pH meter was used to detect the ranges of tumor interstitial tissue pH, and immunohistochemical analysis was adopted to examine hypoxia within the tumor microenvironment. The tumor inhibition rate of the ES + RT group was significantly higher compared with the other three groups (P<0.05). Following treatment, the lactate levels decreased in all three treatment groups compared with the control, particularly in the ES + RT group (P<0.05). Reduced LDH expression and hypoxic fraction in the tumor microenvironment were also observed in the ES + RT group (P<0.05). Furthermore, changes from acidic to alkaline pH in the tumor microenvironment were detected in the ES + RT group. The present study suggested that Endostar is involved in the regulation of metabolism and tumor microenvironment hypoxia, which may be responsible for the enhanced antitumor effect of Endostar in combination with radiotherapy.

Systemic delivery of micelles loading with paclitaxel using N-succinyl-palmitoyl-chitosan decorated with cRGDyK peptide to inhibit non-small-cell lung cancer

This study aimed to prepare efficient cRGDyK peptide-decorated micelles for the targeted therapy of non-small-cell lung cancer (NSCLC). An amphiphilic copolymer N-succinyl-palmitoyl-chitosan (SPCS) was synthesized and characterized. cRGDyK peptide is a ligand that can target tumors via specific binding integrin receptor overexpressed on tumor neovascularization and cells. cRGDyK-functionalized SPCS micelles loaded with paclitaxel (PTX/cRGDyK-SPCS) were prepared by film dispersion method and then characterized according to morphology, size, and zeta potential. PTX/cRGDyK-SPCS micelles presented pH-triggered drug release behavior under acidic conditions. The accumulation of micelles detected by laser confocal fluorescence microscopy and flow cytometry showed that cRGDyK-SPCS micelles were easily taken up by A549 cells marked with the luciferase gene (luc-A549). Meanwhile, co-localization of the micelles and lysosomes was recorded dynamically using a live cell station. MTT assays and cell apoptosis studies revealed that cell viability was significantly inhibited by PTX/cRGDyK-SPCS micelles. More importantly, in vivo animal studies showed that cRGDyK-SPCS micelles mainly accumulated in the orthotopic tumor site. PTX/cRGDyK-SPCS micelles exhibited better anti-tumor activity in subcutaneous and orthotopic lung tumors compared with PTX/SPCS micelles and Taxol(®). These results suggested that PTX/cRGDyK-SPCS micelles had better cancer targeting capacity and superior anti-tumor efficacy. Thus, these micelles have great potential as novel carriers in delivering anti-tumor drugs.

mRNA and microRNA expression profiles of radioresistant NCI-H520 non-small cell lung cancer cells

To elucidate the mechanism of radioresistance in non-small cell lung cancer (NSCLC) cells and to identify key molecules conferring radioresistance, the radioresistant subclone NCI-H520/R, derived from the NCI-H520 NSCLC cell line, was established with eight rounds of sublethal irradiation. The radioresistant features were subsequently assessed using a clonogenic assay, analysis of apoptosis and an MTT assay, the gene expression levels were examined using an Agilent Whole Human Genome 4×44 k Oligo microarray and Agilent Human miRCURY™ LNA array, and confirmed by reverse transcription-quantitative polymerase chain reaction. Pathway analysis and Gene Ontology (GO) analysis were performed to determine the biological functions of the subset of differentially expressed genes. miRNA-mRNA correlation analysis between the expression levels of each miRNA and all its predicted target genes was performed to further understand the radioresistance in the NCI-H520 cells. Following eight rounds of sublethal irradiation, a total of 2,862 mRNAs were significantly differentially expressed in the NCI-H520/R cells, including 893 upregulated genes and 1,969 downregulated genes. A total of 162 upregulated miRNAs and 274 downregulated miRNAs were significantly deregulated in the NCI-H520/R cells. Multiple core regulatory processes and signaling pathways were identified as being of likely relevance to radioresistance in NCI-H520/R cells, including the mitogen-activated protein kinase signaling pathway and neurotrophin signaling pathway. The expression of genes associated with radioresistance reflects the complex biological processes involved in clinical cancer cell eradication and requires further investigation for future enhancement of therapy.

Downregulation of ubiquitin inhibits the proliferation and radioresistance of non-small cell lung cancer cells in vitro and in vivo

Radioresistance has been an important factor in restricting efficacy of radiotherapy for non-small cell lung cancer (NSCLC) patients and new approaches to inhibit cancer growth and sensitize irradiation were warranted. Despite the important role of ubiquitin/proteasome system (UPS) during cancer progression and treatment, the expression and biological role of ubiquitin (Ub) in human NSCLC has not been characterized. In this study, we found that ubiquitin was significantly overexpressed in 75 NSCLC tissues, compared to their respective benign tissues by immunohistochemistry (P < 0.0001). Knock-down of ubiquitin by mixed shRNAs targeting its coding genes ubiquitin B (UBB) and ubiquitin C (UBC) suppressed the growth and increased the radiosensitivity in NSCLC H1299 cells. Apoptosis and γ H2AX foci induced by X-ray irradiation were enhanced by knock-down of ubiquitin. Western blot and immunostaining showed that knock-down of ubiquitin decreased the expression and translocation of NF-κB to the nucleus by reduced phospho-IκBα after irradiation. Suppression of ubiquitin decreased the proliferation and radioresistance of H1299 transplanted xenografts in nude mice by promoting apoptosis. Taken together, our results demonstrate the critical role of ubiquitin in NSCLC proliferation and radiosensitivity. Targeting ubiquitin may serve as a potentially important and novel approach for NSCLC prevention and therapy.

Concurrent systemic therapy with radiotherapy for the treatment of poor-risk patients with unresectable stage III non-small-cell lung cancer: a review of the literature

BACKGROUND

There is no consensus on the therapeutic approach to poor-risk patients with unresectable stage III non-small-cell lung cancer (NSCLC), despite the increasing number of these patients in current clinical practice. In terms of survival, the combination of concurrent systemic therapy with standard radiotherapy might be advantageous over radiotherapy alone. The purpose of this review is to ascertain the feasibility, safety and efficacy of the combination of concurrent systemic therapy and standard radiotherapy in these patients.

METHODS

A computer-based literature search was carried out using PubMed and Science Direct for relevant publications; data reported at major conferences in abstract form were also included.

RESULTS

In unresectable stage III NSCLC, advanced age, poor performance status, weight loss and comorbidities are factors that influence treatment options and disease outcomes in clinical practice. Prospective studies including poor-risk patients have been reviewed. Trials specifically recruiting poor-risk patients have been separated into those using chemotherapy and those using targeted agents with or without chemotherapy. Only two phase III studies specifically including poor-risk patients have been published. Some recent studies suggested that tolerable radio-sensitizing therapy combined with radiotherapy can provide longer survival outcomes than those reported earlier with chemo-radiotherapy or with radiotherapy alone.

CONCLUSIONS

There is an unmet need to develop well-designed clinical trials with tolerable combinations of systemic therapy and radiotherapy specifically tailored to this lung cancer population. Such trials should incorporate careful comorbidity measurement and, in older adults, a validated geriatric assessment.

Interaction of radiation therapy with molecular targeted agents

The development of molecular targeted therapeutics in oncology builds on many years of scientific investigation into the cellular mechanics of malignant transformation and progression. The past two decades have brought an accelerating pace to the clinical investigation of new molecular targeted agents, particularly in the setting of metastatic disease. The integration of molecular targeted agents into phase III clinical trial design has lagged in the curative treatment setting, particularly in combination with established therapeutic modalities such as radiation. In this review, we discuss the interaction of radiation and molecular targeted therapeutics. The dynamics of cellular and tumor response to radiation offer unique opportunities for beneficial interplay with molecular targeted agents that may go unrecognized with conventional screening and monotherapy clinical testing of novel agents. By using epidermal growth factor receptor (EGFR) as a primary example, we discuss recent clinical studies that illustrate the potential synergy of molecular targeted agents with radiation and highlight the clinical value of such interactions. For various molecular targeted agents, their greatest clinical impact may rest in combination with radiation, and efforts to facilitate systematic investigation of this approach appear highly warranted.

Combining targeted agents and hypo- and hyper-fractionated radiotherapy in NSCLC

Radical radiotherapy remains the cornerstone of treatment for patients with unresectable locally advanced non small cell lung cancer (NSCLC) either as single modality treatment for poor performance status patients or with sequential or concomitant chemotherapy for good performance status patients. Advances in understanding of tumour molecular biology, targeted drug development and experiences of novel agents in the advanced disease setting have brought targeted agents into the NSCLC clinic. In parallel experience using modified accelerated fractionation schedules in locally advanced disease have demonstrated improved outcomes compared to conventional fractionation in the single modality and sequential chemo-radiotherapy settings. Early studies of targeted agents combined with (chemo-) radiotherapy in locally advanced disease in different clinical settings are discussed below and important areas for future studies are high-lighted.

Targeted drugs in combination with radiotherapy for the treatment of solid tumors: current state and future developments

The continuously rising use of novel drugs, especially of molecules belonging to the group of targeted drugs is now shaping the therapeutic landscape. However, treatment combinations of targeted drugs with radiotherapy are still rare. Only the monoclonal antibody cetuximab (Erbitux®) has been approved for the treatment of locally advanced squamous cell cancer of the head and neck in combination with radiotherapy. Several targeted compounds are in advanced stages of clinical development for combination treatments with radiotherapy, of which substances with either anti-EGFR or anti-angiogenic mechanisms, such as trastuzumab, panitumumab, erlotinib, cilengitide and bevacizumab are the most promising. Aim of this article is to provide, mainly from a radio-oncological point of view, an overview about the current state as well as to give an outlook on the near future of the most advanced targeted combined treatment concepts for solid tumors.

Progress of clinical research on targeted therapy combined with thoracic radiotherapy for non-small-cell lung cancer

The combination of radiotherapy and targeted therapy is an important approach in the application of targeted therapy in clinical practice, and represents an important opportunity for the development of radiotherapy itself. Numerous agents, including epidermal growth factor receptor, monoclonal antibodies, tyrosine kinase inhibitors, and antiangiogenic therapies, have been used for targeted therapy. A number of studies of radiotherapy combined with targeted therapy in non-small-cell lung carcinoma have been completed or are ongoing. This paper briefly summarizes the drugs involved and the important related clinical research, and indicates that considerable progress has been made with the joint efforts of the two disciplines. Many issues, including drug selection, identification of populations most likely to benefit, timing of administration of medication, and side effects of treatment require further investigation. However, further fundamental research and accumulation of clinical data will provide a more comprehensive understanding of these therapies. Targeted therapy in combination with radiotherapy has a bright future.

Concomitant EGFR inhibitors combined with radiation for treatment of non-small cell lung carcinoma

Epidermal growth factor receptor (EGFR) is considered to be one of the key driver genes in non-small cell lung cancer (NSCLC). Several clinical trials have shown great promise of EGFR tyrosine kinase inhibitors (TKIs) in the first-line treatment of NSCLC. Many advances have been made in the understanding of EGFR signal transduction network and the interaction between EGFR and tumor microenvironment in mediating cancer survival and development. The concomitant targeted therapy and radiation is a new strategy in the treatment of NSCLC. A number of preclinical studies have demonstrated synergistic anti-tumor activity in the combination of EGFR inhibitors and radiotherapy in vitro and in vivo. In the present review, we discuss the rationale of the combination of EGFR inhibitors and radiotherapy in the treatment of NSCLC.

[Clinical developments for the EGFR-TKI combined with radiotherapy in advanced non-small cell lung cancer]

Lung cancer is one of the most common malignant tumor in the world, severely threatening human life. Recently, targeted therapy such as the epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) made huge progress in treatment of lung cancer. EGFR-TKIs, with its high selectivity and low toxicity, is the first choice for EGFR-mutated patients in stage IV non-small cell lung cancer (NSCLC). However, secondary drug resistance becomes a clinical problem to be urgently resolved. In recent years, a series of preclinical studies showed that EGFR-TKI can enhance the antitumor activity of ionizing radiation. Therefore, EGFR-TKI combined with radiation is extremely promising therapy pattern for advanced NSCLC. This review will discuss the research status in EGFR-TKI and radiotherapy for advanced NSCLC.

Long-term survival of stage T4N0-1 and single station IIIA-N2 NSCLC patients treated with definitive chemo-radiotherapy using individualised isotoxic accelerated radiotherapy (INDAR)

BACKGROUND

Non-small cell lung cancer (NSCLC) stage T4N0-1 or single nodal station IIIA-N2 are two stage III sub-groups for which the outcome of non-surgical therapy is not well known. We investigated the results of individualised isotoxic accelerated radiotherapy (INDAR) and chemotherapy in this setting.

METHODS

Analysis of NSCLC patients included in 2 prospective trials (NCT00573040 and NCT00572325) stage T4N0-1 or IIIA-N2 with 1 pathologic nodal station, treated with chemo-radiotherapy (CRT) using INDAR with concurrent or sequential platinum-based chemotherapy. Overall survival (OS) was updated and calculated from date of diagnosis (Kaplan-Meier). Toxicity was scored following CTCAEv3.0. To allow comparison with other articles the subgroups were also analysed separately for toxicity, progression free and overall survival.

RESULTS

83 patients (42 T4N0-1 and 41 IIIA-N2) were identified: the median radiotherapy dose was 65Gy. Thirty-seven percent of patients received sequential CRT and 63% received concurrent CRT. At a median follow-up of 48 months the median OS for T4N0-1 patients was 34 months with 55% 2-year survival and 25% 5-year survival. For stage IIIA-N2 at a median follow-up of 50 months the median OS was 26 months with 2- and 5-year survival rates of 53% and 24%, respectively.

CONCLUSION

Chemo-radiation using INDAR yields promising survival results in patients with single-station stage IIIA-N2 or T4N0-1 NSCLC.