Double-blind placebo-controlled randomized clinical trial evaluating doxycycline effects on chemotherapy-induced oral mucositis

Selective Inhibitors of Medium-Size S1' Pocket Matrix Metalloproteinases: A Stepping Stone of Future Drug Discovery

Among various matrix metalloproteinases (MMPs), MMPs having medium-size S1' pockets are established as promising biomolecular targets for executing crucial roles in cancer, cardiovascular diseases, and neurodegenerative diseases. However, no such MMP inhibitors (MMPIs) are available to date as drug candidates despite a lot of continuous research work for more than three decades. Due to a high degree of structural resemblance among these MMPs, designing selective MMPIs is quite challenging. However, the variability and uniqueness of the S1' pockets of these MMPs make them promising targets for designing selective MMPIs. In this perspective, the overall structural aspects of medium-size S1' pocket MMPs including the unique binding patterns of enzyme-inhibitor interactions have been discussed in detail to acquire knowledge regarding selective inhibitor designing. This overall knowledge will surely be a curtain raiser for the designing of selective MMPIs as drug candidates in the future.

Doxycycline: An option in the treatment of ulcerated oral lesions?

WHAT IS KNOWN AND OBJECTIVES

In addition to its antimicrobial effect, doxycycline has potent anti-inflammatory activity. In view of these pharmacological characteristics, its use in the management of inflammatory, autoimmune and granulomatous diseases has been proposed. The objective of this study was to investigate, through a systematic literature review, the effect of doxycycline on pain and healing of ulcerated lesions of the mouth.

METHODS

An electronic search was performed in accordance with PRISMA guidelines in PubMed, Cochrane Central Register, Web of Science, Bireme/LILACS and Scopus databases. Controlled, randomized clinical trials were selected. The concentration of doxycycline, frequency of application, pain relief and clinical remission of the lesions were analysed.

RESULTS AND DISCUSSION

According to the inclusion criteria, five articles were selected. In four of these studies, doxycycline was used in the treatment of aphthous stomatitis, and in one study, it was used in the treatment of herpes labialis. In all studies, the drug was used topically, both as a hydrogel and as a crushed tablet (along with a prosthetic adhesive). The groups treated with doxycycline showed faster healing of lesions and lower pain scores compared to placebo.

WHAT IS NEW AND CONCLUSION

The present study suggests that topical doxycycline has a positive effect on the treatment of recurrent aphthous ulceration and herpes labialis. Experimental animal studies and double-blind randomized clinical trials should be performed on other oral lesions, such as traumatic ulcers and mucositis.

Selective MMP Inhibition, Using AZD3342, to Reduce Gastrointestinal Toxicity and Enhance Chemoefficacy in a Rat Model

BACKGROUND

The common cytotoxic mechanisms that underpin chemoefficacy and toxicity have hampered efforts to deliver effective supportive care interventions, particularly for gastrointestinal (GI) toxicity. Matrix metalloproteinases (MMPs) have been implicated in both tumor growth and GI toxicity, and as such MMP inhibitors present as a novel therapeutic avenue to simultaneously enhance treatment efficacy and reduce toxicity.

OBJECTIVES

The aim of this study was to determine the efficacy of an MMP-9/12 inhibitor, AZD3342, on tumor growth and GI toxicity in a rat model.

METHODS

Female tumor-bearing Dark Agouti rats (n = 90) were divided into 4 groups: vehicle control; methotrexate (MTX); AZD3342, and MTX + AZD3342. Tumors were measured daily (for 5 days) using digital calipers. GI toxicity was assessed using well-established clinical markers (diarrhea/weight loss), histopathological analysis, and functional assessment of intestinal barrier permeability.

RESULTS

AZD3342 delayed the onset of severe diarrhea by 1 day (vs. MTX) but was unable to improve the overall severity of diarrhea. No changes were detected in tissue morphology or intestinal barrier function. AZD3342 alone suppressed tumor growth (p = 0.003 vs. vehicle) but did not enhance the efficacy of MTX.

CONCLUSIONS

This study showed partial efficacy of AZD3342 in reducing tumor growth and delaying the onset of severe diarrhea caused by MTX in rats. We suggest further studies be undertaken targeting appropriate scheduling of AZD3342 as well as investigating different cytotoxic therapies that strongly activate MMP signaling.