Palifermin for management of treatment-induced oral mucositis in cancer patients

Production of a 135-residue long N-truncated human keratinocyte growth factor 1 in Escherichia coli

BACKGROUND

Palifermin (trade name Kepivance®) is an amino-terminally truncated recombinant human keratinocyte growth factor 1 (KGF-1) with 140 residues that has been produced using Escherichia coli to prevent and treat oral mucositis following radiation or chemotherapy. In this study, an amino-terminally shortened KGF-1 variant with 135 residues was produced and purified in E. coli, and its cell proliferation activity was evaluated.

RESULTS

We expressed soluble KGF-1 fused to thioredoxin (TRX) in the cytoplasmic fraction of E. coli to improve its production yield. However, three N-truncated forms (KGF-1 with 140, 138, and 135 residues) were observed after the removal of the TRX protein from the fusion form by cleavage of the human enterokinase light chain C112S (hEK_L C112S). The shortest KGF-1 variant, with 135 residues, was expressed by fusion with TRX via the hEK_L cleavage site in E. coli and purified at high purity (> 99%). Circular dichroism spectroscopy shows that purified KGF-1₁₃₅ had a structure similar to that of the KGF-1₁₄₀ as a random coiled form, and MCF-7 cell proliferation assays demonstrate its biological activity.

CONCLUSIONS

We identified variations in N-terminus-truncated KGF-1 and selected the most stable form. Furthermore, by a simple two-step purification, highly purified KGF-1₁₃₅ was obtained that showed biological activity. These results demonstrate that KGF-1₁₃₅ may be considered an alternative protein to KGF-1.

Photobiomodulation effects on head and neck squamous cell carcinoma (HNSCC) in an orthotopic animal model

BACKGROUND

Photobiomodulation (PBM) has shown efficacy in preventing and treating cancer therapy-induced mucositis and dermatitis. However, there is contradictory information regarding the effect of PBM on (pre)malignant cells, which has led to questions regarding the safety of this technique. We address this issue using an orthotopic mouse model (Cal-33) with human squamous cell carcinoma of the oral cavity.

METHODS

Mice with actively growing orthotopic Cal-33 head and neck carcinoma tumors were divided into 4 groups: control, PBM only, radiation therapy (RT) only, and PBM + RT. We performed three experiments: (1) PBM at 660 nm, 18.4 J/cm², and 5 RT × 4 Gy doses delivered daily; (2) PBM at 660 nm, 18.4 J/cm², and 1 × 15 Gy RT; and (3) PBM at 660 nm + 850 nm, 45 mW/cm², 3.4 J/cm², and 1 × 15 Gy RT. Mice were weighed daily and tumor volumes were evaluated by IVIS. Survival time was also evaluated.

RESULTS

Animals treated with RT survived significantly longer and had significantly smaller tumor volume when compared with the control and PBM-only treatment groups. No significant differences were noted between the RT alone and PBM + RT groups in any of the experiments.

CONCLUSION

Our results suggest that PBM at the utilized parameters does not provide protection to the tumor from the killing effects of RT.

Craniomaxillofacial Disorders and Solutions in Humans and Animals

Cross-disciplinary collaborations have initiated translational studies in an effort to harness naturally occurring diseases in companion animals to accelerate the development of new treatment modalities, drugs, and device inventions. These synergistic collaborations can identify clinically relevant models that offer the opportunity to conduct rigorous translational investigations. However, the relationship between craniomaxillofacial diseases in companion animals and humans has been widely overlooked. We report here an innovative and visionary 2-d symposium that was organized to gather professionals working on craniomaxillofacial disorders and solutions in humans and/or animals from multiple disciplines, including veterinary physicians, basic scientists, biomedical engineers, physicians, and dentists. The symposium provided a platform for junior and senior investigators and basic science and clinical researchers to network, collaborate, and develop a new clinical and translational framework for accelerated therapy development.

Text mining-based in silico drug discovery in oral mucositis caused by high-dose cancer therapy

INTRODUCTION

Oral mucositis (OM) is a major dose-limiting side effect of chemotherapy and radiation used in cancer treatment. Due to the complex nature of OM, currently available drug-based treatments are of limited efficacy.

OBJECTIVES

Our objectives were (i) to determine genes and molecular pathways associated with OM and wound healing using computational tools and publicly available data and (ii) to identify drugs formulated for topical use targeting the relevant OM molecular pathways.

METHODS

OM and wound healing-associated genes were determined by text mining, and the intersection of the two gene sets was selected for gene ontology analysis using the GeneCodis program. Protein interaction network analysis was performed using STRING-db. Enriched gene sets belonging to the identified pathways were queried against the Drug-Gene Interaction database to find drug candidates for topical use in OM.

RESULTS

Our analysis identified 447 genes common to both the "OM" and "wound healing" text mining concepts. Gene enrichment analysis yielded 20 genes representing six pathways and targetable by a total of 32 drugs which could possibly be formulated for topical application. A manual search on ClinicalTrials.gov confirmed no relevant pathway/drug candidate had been overlooked. Twenty-five of the 32 drugs can directly affect the PTGS2 (COX-2) pathway, the pathway that has been targeted in previous clinical trials with limited success.

CONCLUSIONS

Drug discovery using in silico text mining and pathway analysis tools can facilitate the identification of existing drugs that have the potential of topical administration to improve OM treatment.

Keratinocyte growth factor administration attenuates murine pulmonary mycobacterium tuberculosis infection through granulocyte-macrophage colony-stimulating factor (GM-CSF)-dependent macrophage activation and phagolysosome fusion

Augmentation of innate immune defenses is an appealing adjunctive strategy for treatment of pulmonary Mycobacterium tuberculosis infections, especially those caused by drug-resistant strains. The effect of intranasal administration of keratinocyte growth factor (KGF), an epithelial mitogen and differentiation factor, on M. tuberculosis infection in mice was tested in prophylaxis, treatment, and rescue scenarios. Infection of C57BL6 mice with M. tuberculosis resulted in inoculum size-dependent weight loss and mortality. A single dose of KGF given 1 day prior to infection with 10(5) M. tuberculosis bacilli prevented weight loss and enhanced pulmonary mycobacterial clearance (compared with saline-pretreated mice) for up to 28 days. Similar effects were seen when KGF was delivered intranasally every third day for 15 days, but weight loss and bacillary growth resumed when KGF was withdrawn. For mice with a well established M. tuberculosis infection, KGF given every 3 days beginning on day 15 postinoculation was associated with reversal of weight loss and an increase in M. tuberculosis clearance. In in vitro co-culture experiments, M. tuberculosis-infected macrophages exposed to conditioned medium from KGF-treated alveolar type II cell (MLE-15) monolayers exhibited enhanced GM-CSF-dependent killing through mechanisms that included promotion of phagolysosome fusion and induction of nitric oxide. Alveolar macrophages from KGF-treated mice also exhibited enhanced GM-CSF-dependent phagolysosomal fusion. These results provide evidence that administration of KGF promotes M. tuberculosis clearance through GM-CSF-dependent mechanisms and enhances host defense against M. tuberculosis infection.

Topical KGF treatment as a therapeutic strategy for vaginal atrophy in a model of ovariectomized mice

One of the most frequent complaints for post-menopausal women is vaginal atrophy, because of reduction in circulating oestrogens. Treatments based on local oestrogen administration have been questioned as topic oestrogens can reach the bloodstream, thus leading to consider their safety as controversial, especially for patients with a history of breast or endometrial cancers. Recently, growth factors have been shown to interact with the oestrogen pathway, but the mechanisms still need to be fully clarified. In this study, we investigated the effect of keratinocyte growth factor (KGF), a known mitogen for epithelial cells, on human vaginal mucosa cells, and its potential crosstalk with oestrogen pathways. We also tested the in vivo efficacy of KGF local administration on vaginal atrophy in a murine model. We demonstrated that KGF is able to induce proliferation of vaginal mucosa, and we gained insight on its mechanism of action by highlighting its contribution to switch ERα signalling towards non-genomic pathway. Moreover, we demonstrated that KGF restores vaginal trophism in vivo similarly to intravaginal oestrogenic preparations, without systemic effects. Therefore, we suggest a possible alternative therapy for vaginal atrophy devoid of the risks related to oestrogen-based treatments, and a patent (no. RM2012A000404) has been applied for this study.

Factors associated with pharyngoesophageal stricture in patients treated with concurrent chemotherapy and radiation therapy for oropharyngeal squamous cell carcinoma

BACKGROUND

The purpose of this study was to elucidate factors associated with pharyngoesophageal strictures after treatment for head and neck squamous cell carcinoma (SCC).

METHODS

We conducted a retrospective review of patients receiving cisplatin and 5-fluorouracil chemotherapy combined with concurrent hyperfractionated radiation therapy for oropharyngeal squamous cell carcinoma.

RESULTS

Strictures developed in 13 of 67 patients (19%). Strictures were associated with tumor location (tonsil vs base of tongue; p = .03), neck dissection after completion of therapy (p = .03), and the duration of treatment-induced mucositis (weeks with mucositis grade ≥2; National Cancer Institute (NCI) Common Toxicity Criteria; p < .001). Age, sex, race, tumor stage, nodal stage, American Joint Committee on Cancer (AJCC) stage, human papillomavirus (HPV) status, smoking, radiation dose, maximum severity of mucositis, amifostine use, and pretreatment swallow dysfunction were not significantly associated with stricture. In multivariate analysis, only duration of mucositis, after controlling for age, sex, and tumor location, remained highly significant (p < .01).

CONCLUSION

The duration of treatment-related mucositis is an independent risk factor for stricture formation in patients with oropharyngeal SCC treated with concurrent chemotherapy and radiation therapy.