You will be shown a paragraph from a biomedical research article. Your task is to extract all drug combinations appearing in a specific sentence within in the paragraph. Each drug combination should be assigned to one of the following three categories:

- POS: Indicates a positive interaction between the drugs in the combination; for instance, drugs that have an additive or synergistic effect.
- NEG: Indicates a negative interaction between the drugs in the combination; for instance, combining these drugs might result in adverse side effects, or might reduce their efficacy.
- COMB: Indicates that the drugs are given in combination, but the type of interaction between the drugs cannot be determined based on the provided context.

Please format your answer as a json array. Each entry in the array should itself be an array formatted as [<drug_1>, <drug_2>, ..., <drug_n>, <category>] where <category> is one of the three categories listed above and <drug_1>, ..., <drug_n> are drug names copied verbatim from the input sentence. Different combinations may involve different numbers of drugs; in other words, the `n` in <drug_n> may vary.

As an example, the following output describes two extracted drug combinations; one between two drugs, and one between three drugs:

[["artesunate", "artemether", "COMB"], ["Nifedipine", "Labetalol", "Prazosin", "POS"]]

The paragraph and specific sentence are below. You should only extract relationships expressed in the specific sentence; the paragraph is provided for context.

In your output, return only the json array and no other text. If no drug combinations appear, return an empty array `[]`.

paragraph: [ Effects of endostatin and doxycycline on microcirculation patterns in melanoma and their relevant molecular mechanisms ] . To investigate the effects of endostatin and doxycycline on microcirculation patterns in melanoma and their molecular mechanisms. ### methods To establish mouse B16 melanoma model by subcutaneous injection of B16 melanoma cell suspension. The mice were divided into 3 experimental groups and 1 control group. To treat the mice in the 3 experimental groups with endostatin, doxycycline, endostatin and doxycycline, respectively, and the control group without any treatment. The tumor volume was measured and recorded to make comparison of their growth rate. To assess the expression of MMP-2, MMP-9 and TIMP-2 by immunohistochemical staining. The three microcirculation patterns of endothelium-dependent vessels, mosaic vessels and vasculogenic mimicry were counted. The activity of MMP-2, MMP-9 between different groups was examined by gelatin zymography. ### results Tumor growth in the three experimental groups was statistically significantly slower than that in the control group. The expression of MMP-2, MMP-9 and TIMP-2 in each treated group was significantly different with that in the control group. The amount of three microcirculation patterns in three experimental groups was less than that of the control group, and the amount of MV and VM in each experimental group was significantly less than that in the control group. By gelatin zymography, the enzyme activity of MMP-9, actived-MMP-2 and MMP-2/proMMP-2 in ES, DOX and ES + DOX group was lower than that in the control group, but the enzyme activity of pro-MMP-2 among the four groups was not significantly different. ### conclusion The combined use of doxycycline and endostatin in melanoma can inhibit the expression of MMPs, influencing the formation of different microcirculation patterns in melanoma.

sentence: [ Effects of endostatin and doxycycline on microcirculation patterns in melanoma and their relevant molecular mechanisms ] .
[["endostatin", "doxycycline", "COMB"]]