Hyperthermia inhibits recombination repair of gemcitabine-stalled replication forks

Development and investigation of a novel device with gemcitabine for hyperthermic intravesical chemotherapy

PURPOSE

To evaluate the safety and efficacy of a novel hyperthermic intravesical chemotherapy (HIVEC) device in combination with gemcitabine.

MATERIALS AND METHODS

A pilot clinical trial was performed on patients with high-risk non-muscle invasive bladder cancer (NMIBC), who received HIVEC via the novel device (BR-PRG). Treatment regimen included eight weekly instillations of intravesical GEM (3 g in 150 mL normal saline [NS]) at a temperature of 45 °C for 60 min. Assessment of adverse events (AEs) was the primary objective of the trial. Disease recurrence and the thermal stability of GEM were also analyzed.

RESULTS

A total of 116 HIVEC treatments were delivered. Fifteen and eighteen patients were included in the effectiveness and safety analysis, respectively. Median follow-up was 12 months; five patients experienced a disease recurrence. One-year cumulative incidence of recurrence was 23.8% in EORTC intermediate risk group and 37.5% in high-risk group. Ten patients experienced at least one AE, with the most common being acute urinary tract infection, followed by urinary tract pain, and hematuria. Two patients experienced acute cystitis (grade 3 AE) and instillations were postponed until full recovery. Other AEs were minor, and no systemic toxicity was observed. The contents of GEM in solution of 0.9% NS or NS mixed with artificial urine were stable at 25 °C, 37 °C, 43 °C, 45 °C, 47 °C and 50 °C for 2 h.

CONCLUSION

GEM can be an ideal drug for use in HIVEC due to its good thermal stability. BR-PRG, combined with GEM was safe and effective in administering HIVEC.

Effect of hyperthermia and proton beam radiation as a novel approach in chordoma cells death and its clinical implication to treat chordoma

PURPOSE

Chordoma is a locally aggressive tumor that most commonly affects the base of the skull/clivus, cervical, and sacral spine. Conventional radiotherapy (RT), cannot be safely increased further to improve disease control due to the risk of toxicity to the surrounding critical structures. Tumor-targeted hyperthermia (HT) combined with Proton Beam Radiation Therapy (PBRT) is known to act as a potent radiosensitizer in cancer control. In this study, we investigated whether PBRT efficacy for chordoma can be enhanced in combination with HT as a radiosensitizer.

MATERIAL AND METHODS

Human chordoma cell lines, U-CH2 and Mug-chor1 were treated in vitro with HT followed by PBRT with variable doses. The colony-forming assay was performed, and dose-response was characterized by linear-quadratic model fits. HSP-70 and Brachyury (TBXT) biomarkers for chordoma aggression levels were quantified by western blot analysis. Gene microarray analysis was performed by U133 Arrays. Pathway Analysis was also performed using IPA bioinformatic software.

RESULTS

Our findings in both U-CH₂ and Mug-Chor1 cell lines demonstrate that hyperthermia followed by PBRT has an enhanced cell killing effect when compared with PBRT-alone (p < .01). Western blot analysis showed HT decreased the expression of Brachyury protein (p < .05), which is considered a biomarker for chordoma tumor aggression. HT with PBRT also exhibited an RT-dose-dependent decrease of Brachyury expression (p < .05). We also observed enhanced HSP-70 expression due to HT, RT, and HT + RT combined in both cell lines. Interestingly, genomic data showed 344 genes expressed by the treatment of HT + RT compared to HT (68 genes) or RT (112 genes) as individual treatment. We also identified activation of death receptor and apoptotic pathway in HT + RT treated cells.

CONCLUSION

We found that Hyperthermia (HT) combined with Proton Beam Radiation (PBRT) could significantly increase chordoma cell death by activating the death receptor pathway and apoptosis which has the promise to treat metastatic chordoma.

Whole-body hyperthermia combined with chemotherapy and intensity-modulated radiotherapy for treatment of advanced nasopharyngeal carcinoma: a retrospective study with propensity score matching

BACKGROUND

Several studies have reported the combination of intracavity or cervical lymph node hyperthermia with chemoradiotherapy (CRT) to improve clinical outcomes in nasopharyngeal carcinoma (NPC), but the combination with whole-body hyperthermia (WBH) for treating NPC is unexplored. We aimed to assess the efficacy of the combination of radiotherapy, chemotherapy and WBH in patients with locoregionally advanced NPC.

METHODS

Between July 2008 and November 2012, 239 newly diagnosed NPC patients were enrolled in a pre-propensity score-matched cohort, including 193 patients who received CRT (CRT group) and 46 who underwent CRT with WBH (HCRT group). The feasibility and clinical outcomes of both groups were evaluated and toxicities assessed. Survival rates were assessed using the Kaplan-Meier method, log-rank test and Cox regression.

RESULTS

Following propensity score matching, 46 patients from each group were included. The 5-year overall survival (OS) rates were 65.2% in the CRT group and 80.3% in the HCRT group (p=.027). In contrast, the other survival outcomes at 5 years were similar between the groups: locoregional recurrence-free survival (LRRFS), 74.7% vs. 87.6% (p=.152); distant metastasis-free survival (DMFS), 67.4% vs. 77.9% (p=.125); and progression-free survival (PFS), 53.1% vs. 69.2% (p=.115). In the multivariate analyses, the only two independent predictors of OS were clinical stage and HCRT.

CONCLUSIONS

These results suggest that WBH, when combined with CRT, can improve the OS of patients with advanced NPC.

mTORC2 regulates ribonucleotide reductase to promote DNA replication and gemcitabine resistance in non-small cell lung cancer

Ribonucleotide reductase (RNR) is the key enzyme that catalyzes the production of deoxyribonucleotides (dNTPs) for DNA replication and it is also essential for cancer cell proliferation. As the RNR inhibitor, Gemcitabine is widely used in cancer therapies, however, resistance limits its therapeutic efficacy and curative potential. Here, we identified that mTORC2 is a main driver of gemcitabine resistance in non-small cell lung cancers (NSCLC). Pharmacological or genetic inhibition of mTORC2 greatly enhanced gemcitabine induced cytotoxicity and DNA damage. Mechanistically, mTORC2 directly interacted and phosphorylated RNR large subunit RRM1 at Ser 631. Ser631 phosphorylation of RRM1 enhanced its interaction with small subunit RRM2 to maintain sufficient RNR enzymatic activity for efficient DNA replication. Targeting mTORC2 retarded DNA replication fork progression and improved therapeutic efficacy of gemcitabine in NSCLC xenograft model in vivo. Thus, these results identified a mechanism through mTORC2 regulating RNR activity and DNA replication, conferring gemcitabine resistance to cancer cells.

Mre11 exonuclease activity removes the chain-terminating nucleoside analog gemcitabine from the nascent strand during DNA replication

The Mre11 nuclease is involved in early responses to DNA damage, often mediated by its role in DNA end processing. MRE11 mutations and aberrant expression are associated with carcinogenesis and cancer treatment outcomes. While, in recent years, progress has been made in understanding the role of Mre11 nuclease activities in DNA double-strand break repair, their role during replication has remained elusive. The nucleoside analog gemcitabine, widely used in cancer therapy, acts as a replication chain terminator; for a cell to survive treatment, gemcitabine needs to be removed from replicating DNA. Activities responsible for this removal have, so far, not been identified. We show that Mre11 3' to 5' exonuclease activity removes gemcitabine from nascent DNA during replication. This contributes to replication progression and gemcitabine resistance. We thus uncovered a replication-supporting role for Mre11 exonuclease activity, which is distinct from its previously reported detrimental role in uncontrolled resection in recombination-deficient cells.

Radiofrequency deep hyperthermia combined with chemotherapy in the treatment of advanced non-small cell lung cancer

Background

In the era of precision medicine, chemotherapy is still considered the cornerstone of treatment for lung cancer patients without gene mutations. How to reduce the toxicity and increase the efficiency of chemotherapy is worth exploring. This study aimed to investigate the curative effects and safety of hyperthermia combined with chemotherapy (HCT) for advanced patients with non-small cell lung cancer (NSCLC), especially those with malignant pleural effusion.

Methods

We retrospectively evaluated medical records of 93 patients with advanced NSCLC (stage IIIB-IV) from March 2011 to January 2014. The patients were divided into HCT and chemotherapy (CT) groups. The HCT group was treated with gemcitabine and cisplatin (GP) regimen combined with regional radiofrequency deep hyperthermia, while the CT group was treated with GP regimen only. Those with malignant pleural effusion extra underwent thoracentesis and intrapleural injection chemotherapy combined with hyperthermic or not. Clinical treatment results and adverse reactions were compared and analyzed after treatment. SPSS 19.0 software (SPSS Inc., USA) was used for statistical data processing. P values less than 0.05 were accepted to be statistically significant.

Results

Among the 93 patients, HCT group included 48 patients (16 patients with malignant pleural effusion), CT group included 45 patients (10 patients with malignant pleural effusion). There was no significant difference between the two groups in patient characteristics. The overall response rate (ORR) of pleural effusions was much better in HCT group than that in CT group (81.2% vs. 40.0%, P = 0.046). The patients in HCT group had lower incidence rate of weakness (12.5% vs. 46.7%, χ² = 13.16, P < 0.001) and gastrointestinal (25.0% vs. 77.8%, χ² = 25.88, P < 0.001) adverse reactions than that in CT group. The objective tumor response and survival showed no significant differences.

Conclusions

Hyperthermia combined with chemotherapy might lead to the development of better therapeutic strategy for advanced NSCLC with malignant pleural effusion patients. Also, it could greatly reduce the chemotherapy toxic effects in the incidence of weakness and gastrointestinal adverse reactions in advanced NSCLC patients.

Preclinical In Vitro and In Vivo Evidence of an Antitumor Effect of CX-4945, a Casein Kinase II Inhibitor, in Cholangiocarcinoma

PURPOSE: We investigated the antitumor effect of the casein kinase II (CK2) inhibitor CX-4945 on cholangiocarcinoma (CCA). METHODS: We assessed the effect of CX-4945 alone and/or in combination with gemcitabine and cisplatin on cell viability, colony formation, and apoptosis of CCA cell lines and on in vivo growth of HuCCT1 xenografts. RESULTS: CX-4945 dose-dependently decreased viability of HuCCT1, EGI-1, and Liv27 and decreased phospho-AKT/total AKT and phospho-PTEN/total PTEN ratios. CX-4945 significantly increased caspase 3/7 activity in a dose- and time-dependent manner. CX-4945 significantly enhanced the effect of gemcitabine or cisplatin on HuCCT1, EGI-1, and Liv27 cells and inhibited the phosphorylation of DNA repairing enzymes XRCC1 and MDC1. Further, CX-4945 alone significantly inhibited growth of HuCCT1 mouse xenograft tumors. Combining CX-4945 with gemcitabine and cisplatin was more potent than CX-4945 alone or gemcitabine/cisplatin. The effect of CX-4945 on cell proliferation, apoptosis, the PI3K/AKT pathway, and DNA repair was confirmed in the mouse xenografts. CONCLUSION: CX-4945 has an antiproliferative effect on CCA and enhances the effect of gemcitabine and cisplatin through its inhibitory effect on the PI3K/AKT pathway and DNA repair.

PARP inhibitors synergize with gemcitabine by potentiating DNA damage in non-small-cell lung cancer

Poly (ADP-ribose) polymerase (PARP) inhibitors have demonstrated great promise in the treatment of patients with deficiencies in homologous recombination (HR) DNA repair, such as those with loss of BRCA1 or BRCA2 function. However, emerging studies suggest that PARP inhibition can also target HR-competent cancers, such as non-small-cell lung cancer (NSCLC), and that the therapeutic effect of PARP inhibition may be improved by combination with chemotherapy agents. In our study, it was found that PARP inhibitors talazoparib (BMN-673) and olaparib (AZD-2281) both had synergistic activity with the common first-line chemotherapeutic gemcitabine in a panel of lung cancer cell lines. Furthermore, the combination demonstrated significant in vivo antitumor activity in an H23 xenograft model of NSCLC compared to either agent as monotherapy. This synergism occurred without loss of HR repair efficiency. Instead, the combination induced synergistic single-strand DNA breaks, leading to accumulation of toxic double-strand DNA lesions in vitro and in vivo. Our study elucidates the underlying mechanisms of synergistic activity of PARP inhibitors and gemcitabine, providing a strong motivation to pursue this combination as an improved therapeutic regimen.

Pancreatic adenocarcinoma response to chemotherapy enhanced with non-invasive radio frequency evaluated via an integrated experimental/computational approach

Although chemotherapy combined with radiofrequency exposure has shown promise in cancer treatment by coupling drug cytotoxicity with thermal ablation or thermally-induced cytotoxicity, limited access of the drug to tumor loci in hypo-vascularized lesions has hampered clinical application. We recently showed that high-intensity short-wave capacitively coupled radiofrequency (RF) electric-fields may reach inaccessible targets in vivo. This non-invasive RF combined with gemcitabine (Gem) chemotherapy enhanced drug uptake and effect in pancreatic adenocarcinoma (PDAC), notorious for having poor response and limited therapeutic options, but without inducing thermal injury. We hypothesize that the enhanced cytotoxicity derives from RF-facilitated drug transport in the tumor microenvironment. We propose an integrated experimental/computational approach to evaluate chemotherapeutic response combined with RF-induced phenotypic changes in tissue with impaired transport. Results show that RF facilitates diffusive transport in 3D cell cultures representing hypo-vascularized lesions, enhancing drug uptake and effect. Computational modeling evaluates drug vascular extravasation and diffusive transport as key RF-modulated parameters, with transport being dominant. Assessment of hypothetical schedules following current clinical protocol for Stage-IV PDAC suggests that unresponsive lesions may be growth-restrained when exposed to Gem plus RF. Comparison of these projections to experiments in vivo indicates that synergy may result from RF-induced cell phenotypic changes enhancing drug transport and cytotoxicity, thus providing a potential baseline for clinically-focused evaluation.

Unique heating curves generated by radiofrequency electric-field interactions with semi-aqueous solutions

Aqueous and nanoparticle-based solutions have been reported to heat when exposed to an alternating radiofrequency (RF) electric-field. Although the theoretical models have been developed to accurately model such a behavior given the solution composition as well as the geometrical constraints of the sample holder, these models have not been investigated across a wide-range of solutions where the dielectric properties differ, especially with regard to the real permittivity. In this work, we investigate the RF heating properties of non-aqueous solutions composed of ethanol, propylene glycol, and glycine betaine with and without varying amounts of NaCl and LiCl. This allowed us to modulate the real permittivity across the range 25-132, as well as the imaginary permittivity across the range 37-177. Our results are in excellent agreement with the previously developed theoretical models. We have shown that different materials generate unique RF heating curves that differ from the standard aqueous heating curves. The theoretical model previously described is robust and accounts for the RF heating behavior of materials with a variety of dielectric properties, which may provide applications in non-invasive RF cancer hyperthermia.

Effects of hyperthermia as a mitigation strategy in DNA damage-based cancer therapies

Utilization of thermal therapy (hyperthermia) is defined as the application of exogenous heat induction and represents a concept that is far from new as it goes back to ancient times when heat was used for treating various diseases, including malignancies. Such therapeutic strategy has gained even more popularity (over the last few decades) since various studies have shed light into understanding hyperthermia's underlying molecular mechanism(s) of action. In general, hyperthermia is applied as complementary (adjuvant) means in therapeutic protocols combining chemotherapy and/or irradiation both of which can induce irreversible cellular DNA damage. Furthermore, according to a number of in vitro, in vivo and clinical studies, hyperthermia has been shown to enhance the beneficial effects of DNA targeting therapeutic strategies by interfering with DNA repair response cascades. Therefore, the continuously growing evidence supporting hyperthermia's beneficial role in cancer treatment can also encourage its application as a DNA repair mitigation strategy. In this review article, we aim to provide detailed information on how hyperthermia acts on DNA damage and repair pathways and thus potentially contributing to various adjuvant therapeutic protocols relevant to more efficient cancer treatment strategies.

A New Imaging Platform for Visualizing Biological Effects of Non-Invasive Radiofrequency Electric-Field Cancer Hyperthermia

Herein, we present a novel imaging platform to study the biological effects of non-invasive radiofrequency (RF) electric field cancer hyperthermia. This system allows for real-time in vivo intravital microscopy (IVM) imaging of radiofrequency-induced biological alterations such as changes in vessel structure and drug perfusion. Our results indicate that the IVM system is able to handle exposure to high-power electric-fields without inducing significant hardware damage or imaging artifacts. Furthermore, short durations of low-power (< 200 W) radiofrequency exposure increased transport and perfusion of fluorescent tracers into the tumors at temperatures below 41°C. Vessel deformations and blood coagulation were seen for tumor temperatures around 44°C. These results highlight the use of our integrated IVM-RF imaging platform as a powerful new tool to visualize the dynamics and interplay between radiofrequency energy and biological tissues, organs, and tumors.

Effects of hyperthermia on DNA repair pathways: one treatment to inhibit them all

The currently available arsenal of anticancer modalities includes many DNA damaging agents that can kill malignant cells. However, efficient DNA repair mechanisms protect both healthy and cancer cells against the effects of treatment and contribute to the development of drug resistance. Therefore, anti-cancer treatments based on inflicting DNA damage can benefit from inhibition of DNA repair. Hyperthermia – treatment at elevated temperature – considerably affects DNA repair, among other cellular processes, and can thus sensitize (cancer) cells to DNA damaging agents. This effect has been known and clinically applied for many decades, but how heat inhibits DNA repair and which pathways are targeted has not been fully elucidated. In this review we attempt to summarize the known effects of hyperthermia on DNA repair pathways relevant in clinical treatment of cancer. Furthermore, we outline the relationships between the effects of heat on DNA repair and sensitization of cells to various DNA damaging agents.