CN113143907A

CN113143907A - Application of dihydromyricetin in preparation of medicine for treating oral cancer

Info

Publication number: CN113143907A
Application number: CN202110298607.2A
Authority: CN
Inventors: 朱润芝; 燕翔; 夏添; 王茜桐; 叶飞; 袁啸; 杨敏
Original assignee: Childrens Hospital of Zhejiang University School of Medicine
Current assignee: Childrens Hospital of Zhejiang University School of Medicine
Priority date: 2021-03-19
Filing date: 2021-03-19
Publication date: 2021-07-23
Anticipated expiration: 2041-03-19
Also published as: CN113143907B

Abstract

The invention relates to an application of dihydromyricetin in preparing a medicament for treating oral cancer. The dihydromyricetin can inhibit the survival rate of oral cancer cells in a dose-dependent manner, promote the apoptosis of the oral cancer cells by up-regulating the expression of an apoptosis-related factor PARP, inhibit the autophagy of the oral cancer cells by reducing the expression of an autophagy-related factor Atg-7 or LC3B, and enhance the anti-cancer effect of the dihydromyricetin on the oral cancer by an autophagy inhibitor bavlomycin A1.

Description

Application of dihydromyricetin in preparation of medicine for treating oral cancer

Technical Field

The invention relates to the technical field of medicines, in particular to application of dihydromyricetin or pharmaceutically acceptable salt thereof in preparing a medicine for treating oral cancer.

Background

Oral cancer refers to a malignant tumor that occurs in the oral cavity. Including lip cancer, gum cancer, tongue cancer, soft and hard palate cancer, maxillofacial cancer, carcinoma of the floor of the mouth, oropharyngeal cancer, salivary gland cancer, and carcinoma of the maxillary sinus, and cancer occurring in the facial skin mucosa. Oral cancer is one of the more common malignant tumors of the head and neck. Oral cancer is common in men. In the case of oral cancer, the cancer of the tongue is most common, followed by a buccal mucosa cancer. Oral cancer is one of high-grade malignant tumors in China, and the incidence rate of the oral cancer is the first malignant tumor of ears, noses and throats. The common clinical symptoms are nasal obstruction, blood in nasal discharge, ear obstruction, hearing loss, double vision, headache and the like. Oral cancer is mostly moderately sensitive to radiation therapy, which is the first treatment option for oral cancer. However, surgical resection and chemotherapy are indispensable for the treatment of more differentiated cancers, later disease processes and recurrence after radiotherapy.

Apoptosis (apoptosis) is an important life phenomenon in multicellular organisms and can be divided into two successive processes of apoptosis presentation and apoptosis implementation. Caspase is considered to be a central performer of apoptosis, and its function to perform apoptosis depends on the enzymatic activity of substrate proteins. Under the stimulation of various physiological and pathological factors, through the complex interaction of multiple factors and multiple ways, Caspase is activated and degrades acting substrates to generate terminal effect events, characteristic morphological physicochemical change is caused, and the process of apoptosis is completed. PARP, as a genome monitoring and DNA repair enzyme, is the first proteolytic substrate identified to be degraded by caspase-3 and other cysteine proteases in apoptosis, and is the most characteristic. Thus, changes in PARP expression in cells are important markers of apoptosis.

Autophagy (autophagy) is a cell biological behavior commonly existing in eukaryotic cells, and is essentially formed by wrapping damaged organelles in cells by a double-layer membrane to form autophagy corpuscles, the source of the membrane is not clear at present, and then the autophagy corpuscles are fused with lysosomes to form autophagy lysosomes so as to degrade the wrapped contents, thereby realizing the metabolism needs of the cells and the renewal of certain organelles. At present, some scholars think that autophagy of cells has a certain protective effect on the cells, especially has great significance on the survival of tumor cells, can enable the tumor cells to maintain the metabolic balance of the tumor cells, obtain necessary protein and timely update damaged organelles, and is one of important mechanisms of tumor drug resistance. It has been shown that sensitivity of cancer cells to chemotherapeutic drugs can be increased by autophagy inhibitors or by knocking out autophagy-related genes.

Dihydromyricetin (DHM), also known as Ampelopsin (Ampelopsin). Flavonoid extracted from leaf of Ampelopsis grossedentata of Ampelopsis of Vitaceae, and having molecular formula of C₁₅H₁₂O₈. As a flavonoid compound, the flavonoid compound shows stronger oxidation resistance and cell growth promotion characteristics. Some experiments show that the dihydromyricetin can effectively relieve the liver tissue necrosis of the acute liver failure, can promote the proliferation of liver cells and obviously improve the survival rate of the acute liver failure model mouse. However, no report has been found on the use of dihydromyricetin for preventing or treating oral cancer.

Disclosure of Invention

The invention discovers that dihydromyricetin can inhibit the proliferation of oral cancer cells, promotes the apoptosis of the oral cancer cells by increasing the expression of apoptosis-related factors PARP and cleared-PARP, and inhibits the autophagy of the oral cancer cells by inhibiting the expression of autophagy-related factors LC3B or Atg-7. The combination of the dihydromyricetin and the autophagy inhibitor bavlomycin A1 further enhances the proliferation inhibition effect of the dihydromyricetin on oral cancer cells, and the combination of the dihydromyricetin and the autophagy inhibitor can achieve the effect of synergistically inhibiting the proliferation of the oral cancer cells (P < 0.01). This result demonstrates that inhibition of autophagy can significantly enhance the proliferation inhibitory activity of dihydromyricetin. Dihydromyricetin plays a role in resisting oral cancer by promoting apoptosis and autophagy inhibition mechanisms of oral cancer cells.

Based on the above contents, the invention provides the following technical scheme:

in one aspect, the invention provides an application of dihydromyricetin or pharmaceutically acceptable salt thereof in preparing a medicament for preventing and/or treating oral cancer.

Further, the oral cancer is selected from the group consisting of buccal cancer, lip cancer, oral squamous cancer, salivary gland cancer, tongue cancer, gum cancer, soft and hard palate cancer, maxilla cancer, cancer of the floor of the mouth, cancer of the maxillary sinus, and cancer occurring in the facial skin mucosa. The oral cancer is preferably tongue cancer, more preferably tongue squamous cell carcinoma.

Further, the dihydromyricetin or the pharmaceutically acceptable salt thereof promotes the apoptosis of the oral cancer cells by up-regulating the expression of an oral cancer cell apoptosis-related protein PARP.

Further, the dihydromyricetin or the pharmaceutically acceptable salt thereof inhibits autophagy of oral cancer cells.

Further, the dihydromyricetin or the pharmaceutically acceptable salt thereof inhibits autophagy of oral cancer cells by reducing the expression of autophagy-related protein Atg-7 or LC 3B.

In another aspect, the present invention provides a use of dihydromyricetin or a pharmaceutically acceptable salt thereof for preparing an autophagy inhibitor.

Further, the dihydromyricetin or the pharmaceutically acceptable salt thereof reduces the expression of the autophagy-related protein Atg-7 or LC3B in oral cancer cells.

In a third aspect, the present invention provides a use of a combination of dihydromyricetin or a pharmaceutically acceptable salt thereof and an autophagy inhibitor in the preparation of a medicament for preventing and/or treating oral cancer.

Further, the oral cancer is selected from buccal cancer, lip cancer, oral squamous cancer, salivary gland cancer, tongue cancer, gum cancer, soft and hard palate cancer, maxilla cancer, oral floor cancer, maxillary sinus cancer, and cancer occurring in facial skin mucosa, the oral cancer is preferably tongue cancer, more preferably tongue squamous cell cancer.

Further, the autophagy inhibitor is bavlomycin a 1.

Preferably, the effective concentration of dihydromyricetin is 20-60 μ M, and the effective concentration of autophagy inhibitor is 0.1 μ M.

Pharmaceutical composition

In another aspect, the present invention provides a pharmaceutical composition comprising dihydromyricetin or a pharmaceutically acceptable salt thereof and one or more pharmaceutically acceptable adjuvants. All modes of administration are contemplated, for example, oral, rectal, parenteral, topical, or by intravenous, intramuscular, intrasternal, or subcutaneous injection, or in a form suitable for inhalation. The formulations may conveniently be presented in discrete dosage units and may be prepared by any of the methods well known in the art of pharmacy, as appropriate. The compounds will generally be formulated with one or more pharmaceutically acceptable ingredients in accordance with known and established practice. Thus, the pharmaceutical compositions may be formulated as liquids, powders, injectable solutions, suspensions, suppositories, and the like.

Formulations for oral use may be presented as tablets or hard capsules wherein the compound is mixed with an inert solid diluent, for example, calcium carbonate, calcium phosphate or kaolin, or as soft gelatin capsules wherein the active ingredient is mixed with water or a miscible solvent such as propylene glycol, PEG and ethanol, or an oily medium such as peanut oil, liquid paraffin or olive oil.

For topical administration in the mouth, the pharmaceutical compositions may take the form of buccal or sublingual tablets, drops or lozenges formulated in conventional manner.

The dihydromyricetin or pharmaceutically acceptable salt thereof may be formulated for parenteral administration by injection, conveniently intravenous, intramuscular or subcutaneous injection, for example by bolus injection or continuous intravenous infusion. Formulations for injection may be presented in unit dosage form, e.g., in ampoules or in multi-dose containers, with an added preservative. The pharmaceutical compositions may take such forms as suspensions, solutions or emulsions in aqueous vehicles, and may contain formulatory agents such as suspending, stabilizing and/or dispersing agents. Alternatively, the compounds may be in powder form for constitution with a suitable vehicle, e.g., sterile, pyrogen-free water, before use.

For intranasal administration, the dihydromyricetin or a pharmaceutically acceptable salt thereof may be used, for example, as a liquid spray, as a powder or in the form of drops.

For administration by inhalation, the dihydromyricetin or a pharmaceutically acceptable salt thereof may be conveniently delivered in aerosol packages by pressurized packs or nebulisers, with the use of a suitable propellant, for example dichlorodifluoromethane, trichlorofluoromethane, dichlorotetrafluoroethane, tetrafluoroethane, heptafluoropropane, carbon dioxide or other suitable gas.

Aqueous suspensions may include pharmaceutically acceptable suspending agents, for example, sodium carboxymethylcellulose, hydroxypropylcellulose, sodium alginate, polyvinylpyrrolidone, and gum arabic; dispersing or wetting agents are, for example, naturally-occurring phosphatides, for example lecithin, or condensation products of an alkylene oxide with fatty acids, for example polyoxyethylene stearate, condensation products of ethylene oxide with long chain aliphatic alcohols, for example heptadecaethylene-oxycetanol, or condensation products of ethylene oxide with partial esters derived from fatty acids and a hexitol such as polyoxyethylene sorbitol monooleate, or condensation products of ethylene oxide with partial esters derived from fatty anhydrides and hexitol anhydrides, for example polyoxyethylene sorbitan monooleate.

Drawings

FIG. 1 chemical Structure of Dihydromyricetin

FIG. 2 inhibition of SSC-4 cells by DHM at different concentrations

FIG. 3 inhibition of SSC-9 cells by DHM at different concentrations

FIG. 4 Effect of DHM treatment on SSC-4 apoptosis-related factors 24h

FIG. 5 Effect of DHM treatment on SSC-9 apoptosis-related factors 24h

FIG. 6 Effect of DHM treatment on SSC-4 autophagy-related factors 24h

FIG. 7 Effect of DHM treatment on SSC-9 autophagy-related factors 24h

FIG. 8 inhibition rates of DHM and BafA1 in combination on SSC-4 cells

FIG. 9 inhibition rates of DHM and BafA1 in combination on SSC-9 cells

Advantageous effects

Detailed Description

The present invention is described in more detail below to facilitate an understanding of the present invention.

Example 1 Effect of DHM on the proliferation of oral cancer cell lines

In vitro culture of oral cancer cell strain

1. Cell source

Human tongue squamous carcinoma cell lines SCC-4 and SCC-9 are owned by the laboratory.

2. Cell culture and passage

For both SCC-4 and SCC-9 cells, 1640 medium (Gibco) was used, and 10% fetal bovine serum (FBS, Gibco) was added to the medium at the time of cell culture. Culturing at 37 ℃ in a 5% CO2 incubator, and digesting and subculturing by using 0.25% pancreatin-EDTA when the cells grow to 80-90% of the bottom of the culture dish.

Secondly, the Effect of DHM on cell proliferation Capacity

Main test materials: dissolving dihydromyricetin (dihydromyricetin, DHM, Sigma) in dimethyl sulfoxide (DMSO) to obtain 50mM concentrated solution, storing at-20 deg.C, and diluting to 1.25,2.5,5,10,20,40,80 and 160 μ M respectively when using; cell Counting Kit (CCK-8, Beyotime), stored at 4 ℃ and directly taken; pancreatin (Gibco); PBS; 96-well plates (CORNING).

The test method comprises the following steps: the cells were digested, centrifuged and resuspended in the corresponding medium, seeded in 96-well plates at a density of 5X 103/well, incubated at 37 ℃ for 24h in a 5% CO2 incubator, the stock medium was removed, freshly prepared medium containing 1.25,2.5,5,10,20,40,80 and 160. mu.M DHM was added and incubation continued for 24h,48h and 72h respectively, 10. mu.L CCK-8 was added to each well, incubated again at 37 ℃ for 2h in a 5% CO2 incubator, carefully shaken and mixed and the absorbance of each well was measured at OD 450nm using a microplate reader. Three replicate groups were set for each concentration.

Third, test results

After 24h of DHM treatment, the SSC-4 inhibition rates of 1.25,2.5,5,10,20,40,80 and 160. mu.M DHM were 15.31%, 32.14%, 34.59%, 35.51% and 43.62%, respectively

43.16% 49.75% 49.36%, the inhibition rate did not change much with increasing DHM concentration. The SSC-4 inhibition by DHM at 1.25,2.5,5,10,20,40,80 and 160. mu.M after 48h of DHM treatment was 51.12%, 52.33%, 53.44%, 85.71% and 89.72%, respectively

85.49% 88.72% 78.11%, the inhibition rate increased in a dose-dependent manner with increasing DHM concentration. After 72h of DHM treatment, SSC-4 inhibition by DHM at 1.25,2.5,5,10,20,40,80 and 160. mu.M was 28.69%, 32.21%, 45.26% and 56.05%, respectively

91.95% 93.66% 93.96% 93.95%, the inhibition rate increased in a dose-dependent manner with increasing DHM concentration (fig. 2).

The SSC-9 inhibition by DHM was 11.30%, 22.40% and 80.60% for 40,80 and 160. mu.M, respectively, after 24h from DHM treatment. The SSC-9 inhibition by DHM was 12.68%, 18.16% and 88.19% at 40,80 and 160. mu.M, respectively, after 48h from DHM treatment. The SSC-9 inhibition rates of 40,80 and 160. mu.M DHM were 2.49% respectively since 72h DHM treatment

6.51 percent and 87.75 percent. DHM has a certain dose-dependent effect on SCC-9 cells, and 80 mu M starts to inhibit the cells by more than 80% after 24h,48h and 72h of DHM action (figure 3)

Example 2 apoptosis-related factor expression Werstern Blotting assay

First, cell culture and passage

Human tongue squamous carcinoma cell lines SCC-4 and SCC-9 are owned by the laboratory, and 10% fetal bovine serum (FBS, Gibco) was added to a 1640 medium (Gibco) during cell culture. The cell line is cultured in a 5% CO2 incubator at 37 ℃, and when the cells grow to 80-90% of the bottom of the culture dish, the cells are digested by using 0.25% pancreatin-EDTA and passaged.

Second, expression detection of apoptosis-related factor

Main test materials: DHM dissolved in dimethyl sulfoxide (DMSO) to prepare 50mM concentrated solution, and the concentrated solution is stored at the temperature of-20 ℃ and is respectively diluted to 20 and 40 mu M when in use, so that the DHM is ready to use; RIPA lysate (Beyotime); PMSF; BCA protein concentration assay kit (Beyotime), rabbit anti-human primary antibody (P53, PARP, cleared-PARP, Caspase3, Actin); horseradish peroxidase conjugated goat anti-rabbit secondary antibody; acrylamide, SDS, ammonium sulfite, Tris-Base, PVDF membrane, ECL luminescence solution (GE Healthcare).

The test method comprises the following steps: after the cells were digested into a cell suspension, the cells were plated in a 60mm petri dish at an appropriate density, incubated at 37 ℃ for about 24 hours in a 5% CO2 incubator, and when the cells grew to about 60% of the bottom of the petri dish, the original culture solution was removed, and freshly prepared culture solutions containing DHM at concentrations of 20. mu.M and 40. mu.M, respectively, were added to continue the culture, and a culture solution without DHM (0. mu.M) was used as a control. The culture was terminated 24h after the addition of DHM, the culture broth was removed and washed twice with PBS, and cells were lysed by adding RIPA lysate containing 1% PMSF. The lysate was centrifuged at 4 ℃ and 12000 Xg/min for 10min, the supernatant was collected, the protein concentration was determined, the protein amount was aliquoted, the protein was separated by 10% SDS-PAGE electrophoresis, transferred to PVDF membrane, blocked with 5% skim milk, washed with TBST (1% Tween 20) and the primary antibody (P53, PARP, cleared-PARP, Caspase3, Actin) was incubated overnight at 4 ℃. TBST wash 5 times for 5min, secondary antibody incubation 1h at room temperature, TBST wash 5 times for 5min, chemiluminescence using ECL luminescence and exposure to dark room, analysis of associated protein expression trends.

Third, test results

SCC-4 cells and SSC-9 cells show a descending trend of P53 and Caspase3 expression along with the increase of DHM concentration when being treated for 24 hours by DHM; the expression of PARP and cleaned-PARP showed increasing trend (FIG. 4, FIG. 5).

The above results indicate that DHM can increase the expression of the SSC-4 and SSC-9 apoptosis-related factor PARP, which may promote SSC-4 and SSC-9 apoptosis by activating PARP.

Example 3 expression of autophagy-related factors Werstern Blotting assay

First, cell culture and passage

Second, expression detection of cell autophagy-related factor

Main test materials: DHM dissolved in dimethyl sulfoxide (DMSO) to prepare 50mM concentrated solution, and the concentrated solution is stored at the temperature of-20 ℃ and is respectively diluted to 20 and 40 mu M when in use, so that the DHM is ready to use; RIPA lysate (Beyotime); PMSF; BCA protein concentration assay kit (Beyotime), rabbit anti-human primary antibody (Atg-7, LC3B, Actin); horseradish peroxidase conjugated goat anti-rabbit secondary antibody; acrylamide, SDS, ammonium sulfite, Tris-Base, PVDF membrane, ECL luminescence solution (GE Healthcare).

The test method comprises the following steps: after the cells were digested into a cell suspension, the cells were plated in a 60mm petri dish at an appropriate density, incubated at 37 ℃ for about 24 hours in a 5% CO2 incubator, and when the cells grew to about 60% of the bottom of the petri dish, the original culture solution was removed, and freshly prepared culture solutions containing DHM at concentrations of 20. mu.M and 40. mu.M, respectively, were added to continue the culture, and a culture solution without DHM (0. mu.M) was used as a control. The culture was terminated 24h after the addition of DHM, the culture broth was removed and washed twice with PBS, and cells were lysed by adding RIPA lysate containing 1% PMSF. The lysate was centrifuged at 4 ℃ and 12000 Xg/min for 10min, the supernatant was collected, the protein concentration was determined, the protein amount was measured, the protein was separated by 10% SDS-PAGE electrophoresis, transferred to PVDF membrane, blocked with 5% skim milk, washed with TBST (1% Tween 20), and incubated overnight at 4 ℃ with primary antibody (Atg-7, LC3B, Actin). TBST wash 5 times for 5min, secondary antibody incubation 1h at room temperature, TBST wash 5 times for 5min, chemiluminescence using ECL luminescence and exposure to dark room, analysis of associated protein expression trends.

Third, test results

After 24h of DHM treatment, the expression of the Atg-7 of the SCC-4 cells shows a descending trend along with the increase of the concentration of the DHM; the expression of LC3B was not significantly changed (fig. 6).

SCC-9 cells show a decreasing trend of LC3B expression with increasing DHM concentration at 24h of DHM treatment; the expression of Atg-7 was not significantly changed (FIG. 7).

The above results indicate that DHM has autophagy inhibition effect on human tongue squamous carcinoma cell lines, which may prevent self-repair of tumor cells by autophagy inhibition mechanism.

Example 4 Effect of DHM in combination with autophagy inhibitors on cell proliferative Capacity

In vitro culture of oral cancer cell strain

1. Cell source

2. Cell culture and passage

Effect of DHM in combination with Barvlosin A1 on cell proliferation potency

Main test materials: dissolving dihydromyricetin (dihydromyricetin, DHM, Sigma) in dimethyl sulfoxide (DMSO) to obtain 50mM concentrated solution, storing at-20 deg.C, and diluting to 1.25,2.5,5,10,20,40,80 and 160 μ M respectively when using; the bafilomycin A1(bafilomycin A1, BafA1) is prepared into 0.1 mu M, and is ready to use; cell Counting Kit (CCK-8, Beyotime), stored at 4 ℃ and directly taken; pancreatin (Gibco); PBS; 96-well plates (CORNING).

The test method comprises the following steps: SSC-4 cells are digested, centrifuged and resuspended in the corresponding medium at 5X 10³Density of/well was plated in 96-well plates, incubated at 37 ℃ in a 5% CO2 incubator for 24h, stock culture was removed, and freshly prepared solutions containing: group A20. mu.M DHM; group B: 0.1 μ M BafA 1; group C20. mu.M DHM and 0.And (3) continuously culturing 1 mu M of culture solution of BafA1 and the blank culture solution control group D, terminating the culture at 24h,48h and 72h of culture, adding 10 mu L of CCK-8 into each well, placing the wells in an incubator at 37 ℃ and 5% CO2 again for 2h, carefully shaking and uniformly mixing, and detecting the light absorption value of each well at OD 450nm of a microplate reader. Three replicate groups were set for each group.

The test method comprises the following steps: SSC-9 cells are digested, centrifuged and resuspended in the corresponding medium at 5X 10³Density of/well was plated in 96-well plates, incubated at 37 ℃ in a 5% CO2 incubator for 24h, stock culture was removed, and freshly prepared solutions containing: group A60. mu.M DHM; group B: 0.1 μ M BafA 1; culturing the culture solution of the group C60 mu M DHM, the group C0.1 mu M BafA1 and the group D blank culture solution control group continuously, stopping culturing for 24h,48h and 72h respectively, adding 10 mu L CCK-8 into each well, culturing again in a 37 ℃ and 5% CO2 incubator for 2h, carefully shaking and uniformly mixing, and detecting the light absorption value of each well at OD 450nm of a microplate reader. Three replicate groups were set for each group.

Third, test results

Since tumor autophagy is an important mechanism leading to drug resistance in many tumors, we further investigated the effect of DHM in combination with the autophagy inhibitor bavlomycin A1 on the proliferative capacity of SSC-4 and SSC-9.

The results show that: group A20. mu.M DHM inhibited SSC-4 by 36.65% (24h)

83.65% (48h) 59.35% (72h), SSC-4 inhibition by 0.1 μ M BafA1 alone < 10% in group B, no significant difference (P >0.05) compared to group D of the blank control, SSC-4 inhibition by 20 μ M MDHM +0.1 μ M BafA1 in combination of 56.73% (24h) 92.69% (48h) 83.30% (72h), significant difference (P <0.05) compared to group A. (FIG. 8)

The inhibition rate of 60 μ M DHM on SSC-9 in group A is 51.25% (24h) 62.96% (48h) 61.66% (72h), the inhibition rate of 0.1 μ M BafA1 on SSC-4 in group B alone is < 10%, and the inhibition rate on SSC-9 in combination with 60 μ M MDHM +0.1 μ M BafA1 is 78.46% (24h) 94.67% (48h) 96.21% (72h) which is very significant compared with group A, and has no significant difference (P <0.05) compared with group A. (FIG. 9)

The results show that the autophagy inhibitor bavlomycin A1 can enhance the inhibition effect of DHM on tongue squamous cell carcinoma SSC-4 and SSC-9, and the combination of the two results produces a synergistic effect.

The foregoing describes preferred embodiments of the present invention, but is not intended to limit the invention thereto. Modifications and variations of the embodiments disclosed herein may be made by those skilled in the art without departing from the scope and spirit of the invention.

Claims

1. Application of dihydromyricetin or pharmaceutically acceptable salt thereof in preparing medicine for preventing and/or treating oral cancer.

2. Use according to claim 1, characterized in that the cancer of the oral cavity is selected from the group consisting of carcinoma of the cheek, carcinoma of the lip, carcinoma of the oral squamous cell, carcinoma of the salivary glands, carcinoma of the tongue, carcinoma of the gingiva, carcinoma of the soft and hard palate, carcinoma of the jawbone, carcinoma of the floor of the mouth, carcinoma of the maxillary sinuses and the cancers occurring in the cutaneous mucosa of the facial skin, said cancer of the oral cavity being preferentially carcinoma of the tongue, more preferably squamous cell carcinoma of the tongue.

3. The use according to any one of claims 1-2, wherein said dihydromyricetin or pharmaceutically acceptable salt thereof promotes apoptosis of oral cancer cells by up-regulating expression of the oral cancer cell apoptosis-related protein PARP.

4. The use according to any one of claims 1-2, wherein said dihydromyricetin, or a pharmaceutically acceptable salt thereof, inhibits autophagy of oral cancer cells.

5. The use according to claim 7, wherein said dihydromyricetin or a pharmaceutically acceptable salt thereof inhibits autophagy of oral cancer cells by reducing the expression of autophagy-related protein Atg-7 or LC 3B.

6. Use of dihydromyricetin or a pharmaceutically acceptable salt thereof in the preparation of an autophagy inhibitor.

7. The use according to claim 6, wherein said dihydromyricetin or pharmaceutically acceptable salt thereof reduces the expression of autophagy-related protein Atg-7 or LC3B in oral cancer cells.

8. Use of a combination of dihydromyricetin or a pharmaceutically acceptable salt thereof and an autophagy inhibitor in the preparation of a medicament for the prevention and/or treatment of oral cancer.

9. Use according to claim 8, the oral cancer being selected from the group consisting of buccal carcinoma, lip cancer, oral squamous carcinoma, salivary gland cancer, tongue cancer, gingival cancer, soft and hard palate cancer, jawbone cancer, oral floor cancer, cancer of the maxillary sinus and cancer occurring in the facial skin mucosa, the oral cancer being preferably tongue cancer, more preferably squamous cell carcinoma of the tongue.

10. Use according to claim 9, wherein the autophagy inhibitor is bavlomycin a1, preferably the effective concentration of dihydromyricetin is 20-60 μ M and the effective concentration of autophagy inhibitor is 0.1 μ M.