Application of honokiol in the preparation of a drug for treating retinoblastoma

Abstract

This application relates to the technical field of drug applications. This application discloses the use of honokiol in the preparation of a drug for treating retinoblastoma. It is discovered for the first time that honokiol has a new effect in treating retinoblastoma, can effectively inhibit the proliferation of retinoblastoma cells, and is of great significance for the development of new drugs for treating retinoblastoma. Experiments have proven that honokiol can inhibit the proliferation of RB cells by promoting apoptosis of RB cells and inducing cell cycle arrest. This application also discovers for the first time that honokiol has a significant therapeutic effect on multi-drug resistant RB cells, providing a new idea for solving the clinical problem of RB chemotherapy resistance. Experiments have proven that honokiol still maintains good sensitivity to RB drug-resistant cells, and its killing effect on RB / CBP drug-resistant cells is similar to that of RB non-drug-resistant cells.

Description

Technical Field

[0001] The present application relates to the technical field of drug applications, and particularly relates to the application of honokiol in the preparation of a drug for treating retinoblastoma. Background Art

[0002] Retinoblastoma (RB) is a dangerous intraocular malignant tumor. Most patients develop the disease before the age of 5. There are approximately 9,000 new cases worldwide each year, ranking first in the incidence of intraocular malignant tumors. RB is the main cause of childhood blindness, prone to intracranial and distant metastases, and often endangers the lives of children.

[0003] Early treatment of RB mostly involves local radiotherapy, photocoagulation or cryotherapy. For patients with advanced RB, combined treatment methods based on chemotherapy are mostly used. However, chemotherapy treatment is prone to drug resistance and inevitable toxicity. Among them, multidrug resistance is the main obstacle in clinical treatment and an important reason for chemotherapy failure. Therefore, there is an urgent need to develop new RB treatment drugs that are safe, effective and have anti-chemotherapy drug resistance.

[0004] Natural products have always been considered an important source of clinical drugs. Many widely used active ingredients of traditional Chinese medicines have good killing effects on tumors. Honokiol (HNK) is a bisphenolic phytocompound extracted from the bark and cones of the traditional Chinese medicine Magnolia officinalis, and has various pharmacological effects such as anti-cancer, anti-inflammatory, antibacterial and antioxidant. At present, the therapeutic effect of HNK on RB, especially the anti-RB effect, has not been reported. Summary of the Invention

[0005] In view of this, the present application provides the application of honokiol in the preparation of a drug for treating retinoblastoma to solve the problem of poor therapeutic effect of retinoblastoma, especially the problem of chemotherapy failure caused by multidrug resistance during the treatment of RB cells.

[0006] In the first aspect, the present application provides the application of honokiol in the preparation of a drug for treating retinoblastoma.

[0007] In an optional embodiment, the structural formula of honokiol in the application of honokiol in the preparation of a drug for treating retinoblastoma is as follows:

[0008]

[0009] In an optional embodiment, the drug is a drug that has an inhibitory effect on human retinoblastoma cells.

[0010] In an optional embodiment, the drug has the effect of inducing apoptosis of human retinoblastoma cells.

[0011] In an alternative embodiment, the drug has the effect of upregulating the expression of caspase-3 in human retinoblastoma cells.

[0012] In an alternative embodiment, the drug has the effect of downregulating the expression of survivin in human retinoblastoma cells.

[0013] In an alternative embodiment, the drug has the effect of inducing cell cycle arrest in human retinoblastoma cells.

[0014] In an alternative embodiment, the drug has an inhibitory effect on drug-resistant human retinoblastoma cells.

[0015] In an alternative embodiment, the drug has an inhibitory effect on human retinoblastoma cells resistant to carboplatin (CBP).

[0016] Compared with the prior art, the beneficial effects of the present application are as follows:

[0017] The present application provides an application of honokiol in the preparation of a drug for treating retinoblastoma. It is first discovered that honokiol has a new effect in treating retinoblastoma, can effectively inhibit the proliferation of retinoblastoma cells, and is of great significance for developing new drugs for treating retinoblastoma. Experiments have proved that honokiol can inhibit the proliferation of RB cells by promoting apoptosis and inducing cell cycle arrest.

[0018] The present application also first discovers that honokiol has a significant therapeutic effect on multi-drug resistant RB cells, providing a new idea for solving the clinical problem of RB chemotherapy resistance. Experiments have proved that honokiol still maintains good sensitivity to RB drug-resistant cells, and its killing effect on RB / CBP drug-resistant cells is similar to that of RB non-drug-resistant cells. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0020] Figure 1 It is the detection of the inhibitory effect of HNK on RB cells by the CCK-8 method in Test Example 1 of the present application;

[0021] Figure 2a It is the detection of the apoptosis of RB cells induced by HNK by flow cytometry in Test Example 1 of the present application;

[0022] Figure 2b It is the comparison of the apoptosis rates of RB cells induced by HNK solutions with different concentrations in Test Example 1 of the present application;

[0023] Figure 3 It is the detection of the effect of HNK on the apoptosis of RB cells by immunofluorescence assay in Test Example 1 of the present application;

[0024] Figure 4a It is the detection of the cell cycle arrest of RB cells induced by HNK by flow cytometry in Test Example 1 of the present application;

[0025] Figure 4b It is the comparison of the cell cycle arrest of RB cells induced by HNK solutions with different concentrations in Test Example 1 of the present application;

[0026] Figure 5 It is the observation of RB cells and RB / CBP drug-resistant cells under a microscope in Test Example 2 of the present application;

[0027] Figure 6 It is the growth curves of RB cells and RB / CBP drug-resistant cells in Test Example 2 of the present application;

[0028] Figure 7 It is the inhibitory effects of carboplatin, etoposide, and vincristine on RB cells and RB / CBP drug-resistant cells in Test Example 2 of the present application;

[0029] Figure 8 It is the inhibitory effect of honokiol at different concentrations and different time points on RB / CBP drug-resistant cells in Test Example 2 of the present application. Detailed implementation manners

[0030] The following embodiments are provided to better further understand the present application, which are not limited to the described optimal implementation manners, and do not constitute limitations on the content and protection scope of the present application. Any product identical or similar to the present application obtained by anyone under the inspiration of the present application or by combining the features of the present application with those of other existing technologies falls within the protection scope of the present application.

[0031] Unless otherwise stated or there are contradictions, the terms or phrases used herein have the following meanings:

[0032] In the present application, regarding the percentage content, unless otherwise specified, for solid-liquid mixing and solid-solid mixing, it refers to the mass percentage, and for liquid-liquid mixing, it refers to the volume percentage.

[0033] In the present application, regarding the percentage concentration, unless otherwise specified, it refers to the final concentration. The final concentration refers to the proportion of the added component in the system after adding the component.

[0034] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the technical field to which this application belongs. The terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0035] This application does not specifically limit the method for obtaining honokiol, which can be prepared by conventional methods in the art and implemented by those skilled in the art, or commercially available products can be purchased conventionally. The honokiol used in the following experiments is a commercially purchased honokiol standard product.

[0036] The chemical structural formula of honokiol (HNK) is:

[0037]

[0038] The human retinoblastoma cell line WERI-Rb-1 (RB cells) used in the following experiments was purchased from the Cell Bank of the Chinese Academy of Sciences and cultured in RPMI-1640 cell medium containing 10% fetal bovine serum and 100 U / ml penicillin / streptomycin, and placed in an incubator at 37 °C and 5% CO2 for culture.

[0039] RPMI-1640 cell medium was purchased from Gibco, USA;

[0040] DMSO was purchased from Gibco, USA;

[0041] Honokiol was purchased from Beijing Solarbio Science & Technology Co., Ltd., China;

[0042] Carboplatin was purchased from Beijing Solarbio Science & Technology Co., Ltd., China;

[0043] Etoposide was purchased from Beijing Solarbio Science & Technology Co., Ltd., China;

[0044] Vincristine was purchased from Beijing Solarbio Science & Technology Co., Ltd., China.

[0045] The following further describes this application in detail with specific embodiments, and these embodiments should not be construed as limiting the scope claimed by this application. For those experiments without specific experimental steps or conditions noted below, the operations or conditions of the conventional experimental steps described in the literature in this field can be followed. For reagents or instruments without the manufacturer noted, they are all conventional reagent products that can be obtained through commercial purchase.

[0046] Experimental Example 1 Inhibitory Effect of HNK on RB Cells

[0047] 1. Use the CCK-8 method to determine the inhibitory effect of HNK on RB cells

[0048] RB cells were treated with HNK at different concentrations (0, 20 μM, 40 μM, 60 μM, 80 μM, 100 μM, 120 μM) to study the inhibitory effect of HNK on the proliferation of RB cells, and the survival rate of RB cells at different time points (24 h and 48 h) was detected by CCK-8. The specific steps are as follows:

[0049] RB cells in the logarithmic growth phase were seeded into 96-well plates at a density of 5×10 3 cells per well. HNK was prepared into a 1 mM stock solution with DMSO and then diluted into HNK solutions with different concentrations using serum-free cell culture medium (RPMI-1640 cell culture medium). In experimental groups 1-6, equal volumes of HNK solutions with final concentrations of 20 μM, 40 μM, 60 μM, 80 μM, 100 μM, or 120 μM were added respectively, and the control group was added with an equal volume of DMSO solvent control. Each group was cultured for 24 h and 48 h respectively. Then, 20 μl of CCK-8 reagent was added to each well and cultured for 3 h. The absorbance value (OD) was measured using an enzyme-linked immunosorbent assay (ELISA) reader at 450 nm. The experimental results are as Figure 1 shown, where the abscissa is the concentration of the HNK solution and the ordinate is the survival rate of RB cells; the left figure shows the inhibitory effect of HNK on the proliferation of RB cells when the cells were cultured for 24 h, and the right figure shows the inhibitory effect of HNK on the proliferation of RB cells when the cells were cultured for 48 h.

[0050] The results showed that compared with the control group, the addition of HNK solutions at concentrations of 40 μM, 60 μM, 80 μM, 100 μM, and 120 μM could significantly inhibit the proliferation of RB cells, and with the increase of HNK concentration and the prolongation of the inhibition time, the survival rate of RB cells decreased continuously (P<0.001), that is, the inhibitory effect of HNK showed dose- and time-dependence.

[0051] 2. Honokiol inhibits the proliferation of RB cells by inducing apoptosis

[0052] The apoptosis rate of cells was detected by Annexin V-FITC / PI double staining method. RB cells in the logarithmic growth phase were seeded into 6-well plates at a density of 1×10 6 cells per well. HNK was prepared into a 1 mM stock solution with DMSO and then diluted into HNK solutions with different concentrations using serum-free cell culture medium (RPMI-1640 cell culture medium). In the experimental groups, equal volumes of HNK solutions with final concentrations of 40 μM and 60 μM were added respectively, and the control group was added with an equal volume of DMSO solvent control. The cells were cultured for 24 h respectively. The cells were collected by centrifugation, washed twice with ice-cold PBS, and resuspended. FITC-labeled Annexin-V and propidium iodide (PI) solutions were added and cultured for 15 minutes at room temperature in the dark. The apoptosis rate of cells was detected by flow cytometry.

[0053] In addition, immunofluorescence assay was used to detect the apoptosis of RB cells induced by HNK. RB cells in the logarithmic growth phase were seeded into 6-well plates at a density of 1×10 6 cells per well. The experimental groups were treated with equal volumes of HNK solutions at final concentrations of 40 μM and 60 μM, respectively, and the control group was treated with an equal volume of DMSO as a solvent control. After culturing for 24 h, the cells were collected by centrifugation, washed with PBS, and fixed with 4% paraformaldehyde. The cells were permeabilized with Triton X-100 (0.5%) and blocked with 5% BSA. Then, the cells were incubated with caspase-3 or survivin primary antibody at a dilution of 1:500 at 4 °C overnight. After washing the cells 3 times with TBST, they were incubated with fluorescently conjugated secondary antibody. After washing 3 times with PBST, the cells were stained with DAPI for 1 minute.

[0054] Flow cytometry was used to detect the apoptosis of RB cells induced by HNK as Figure 2a shown. The comparison of the apoptosis rates of RB cells induced by different concentrations of HNK solution is shown in Figure 2b , where the abscissa represents the apoptosis of cells at different stages, and the ordinate represents the apoptosis rate.

[0055] It can be seen from the figure that the apoptosis rates of RB cells in the HNK (40 μM and 60 μM) treatment groups were significantly increased, and the apoptosis rate of RB cells in the high-dose HNK group was significantly higher than that in the low-dose HNK group. The results showed that after 24 h, compared with the control group (the early and late apoptosis rates were 11.20% and 9.64%, respectively), the stimulation with HNK 60 μM (the early and late apoptosis rates were 15.72% and 51.83%, respectively) significantly increased the proportions of early and late apoptotic RB cells (P<0.01), and HNK mainly increased the late apoptosis of RB cells. The above results indicate that HNK can inhibit the proliferation of RB cells by inducing apoptosis.

[0056] Analysis of the results of immunofluorescence assay showed that as Figure 3 shown, compared with the control group, the stimulation with HNK (40 μM and 60 μM) could up-regulate the expression of caspase-3 and down-regulate the expression of survivin in RB cells, and the effect of the high-dose HNK group was more significant. The above results indicate that HNK induces apoptosis by changing the expression of caspase-3 and survivin in RB cells.

[0057] 3. Honokiol inhibits the proliferation of RB cells by inducing cell cycle arrest

[0058] Flow cytometry was used to detect the cell cycle arrest of RB cells induced by HNK. RB cells in the logarithmic growth phase were seeded into 6-well plates at a density of 1×10 6Cells. In the experimental groups, an equal volume of HNK solution with final concentrations of 40 μM and 60 μM respectively was added, and in the control group, an equal volume of DMSO solvent was added as a control. The cells were cultured for 24 h. The cells were centrifuged and collected, fixed overnight with 70% ethanol pre-cooled to 4 °C, and then stained with 400 μl of PI solution and 100 μl of ribonuclease A solution at room temperature in the dark for 15 min. The concentration of the PI solution was 50 μg / ml, and the concentration of the ribonuclease A (Ribonuclease A, RNase A) solution was 100 μg / ml. Then, the cell cycle distribution of RB cells was detected by flow cytometry.

[0059] Flow cytometry was used to determine whether HNK inhibits RB cell proliferation by inducing cell cycle arrest. To evaluate the effect of HNK on the RB cell cycle, we treated RB cells with different concentrations of HNK solution (0, 40 μM, 60 μM) for 24 h. The experimental results of detecting HNK-induced RB cell cycle arrest by flow cytometry are as Figure 4a shown, and the comparison of HNK-induced RB cell cycle arrest at different concentrations is as Figure 4b shown, where the abscissa is the cells in different groups; the ordinate is the cell cycle ratio.

[0060] HNK solutions at different concentrations (40 μM and 60 μM) both significantly increased the proportion of RB cells in the G0 / G1 phase (p < 0.05; p < 0.01). The above results indicate that HNK can inhibit the proliferation of RB cells by inducing cell cycle arrest of RB cells in G0 / G1.

[0061] Experimental Example 2 Inhibitory effect of honokiol on carboplatin-resistant retinoblastoma cells

[0062] 1. Construction of RB / CBP-resistant cells

[0063] RB / CBP-resistant cells (RB cells stably growing in carboplatin solution) were constructed by the method of increasing the concentration of carboplatin step by step as follows: RB cells in the logarithmic growth phase were seeded in 96-well plates, 5×10 3Cells. For the first stimulation, a low-concentration carboplatin solution with a final concentration of 25 μM was used (preparation of carboplatin solution: CBP was prepared into a 10 mM stock solution with serum-free medium, and then diluted into carboplatin solutions of different concentrations with serum-free cell medium. The serum-free cell medium was RPMI-1640 cell medium). The cells were stimulated for 2 h, then centrifuged, rinsed once with 5 ml of serum-free cell medium, and after centrifugation, replaced with fresh cell medium (RPMI-1640 cell medium containing 10% fetal bovine serum and 100 U / ml penicillin / streptomycin) for culture. Some cells died until the live cells grew to a certain concentration again (i.e., a large number of cell aggregates appeared). Then, the above steps and the same concentration and volume of carboplatin solution were repeated for stimulation. This concentration of carboplatin solution was stimulated 3 - 4 times in total. After the RB cells could grow stably in the 25 μM carboplatin solution (i.e., a large number of cell aggregates could appear), the same volume of a higher-concentration carboplatin solution was added. Each time, a carboplatin solution with an increasing concentration of 25 μM was used for stimulation (the stimulation concentrations of the carboplatin solution were 50 μM, 75 μM, 100 μM, 125 μM, and 150 μM in sequence). The stimulation process was the same as above. After the RB cells could grow stably in the carboplatin solution with the increased concentration, the concentration of the carboplatin solution was increased again.

[0064] The experimental results showed that by stimulating RB cells with the method of increasing carboplatin concentration, after continuous intermittent stimulation for 6 months, the RB / CBP drug-resistant cells could grow stably in the carboplatin solution with a final concentration of 150 μM. The RB cells without carboplatin solution stimulation and the RB / CBP drug-resistant cells (RB cells growing stably in the carboplatin solution with a final concentration of 150 μM) stimulated by the carboplatin solution were observed under a microscope as Figure 5 shown. By comparing and observing RB cells and RB / CBP drug-resistant cells under a microscope, it was found that the growth density of RB cells was high, and the cells were easily aggregated into grape-like clusters, while the growth density of RB / CBP drug-resistant cells was relatively low, the cells were more dispersed, and it was not easy to form clusters. In summary, through the method of increasing carboplatin concentration for stimulation, RB / CBP drug-resistant cells were constructed and awaited further drug sensitivity testing.

[0065] 2. Growth of RB / CBP drug-resistant cells

[0066] RB cells in the logarithmic growth phase and RB / CBP drug-resistant cells were respectively inoculated into 96-well plates, with 5×10 3 cells per well, and cultured for 0, 12 h, 24 h, 48 h, 72 h, and 96 h respectively. Then, 20 μl of CCK-8 reagent was added to each well and cultured for 3 h. The absorbance value (OD) was measured at 450 nm using an enzyme-linked immunosorbent assay reader. With the absorbance value as the vertical axis and time as the horizontal axis, the growth curves of RB cells and RB / CBP drug-resistant cells were respectively plotted, and then the growth curves before and after drug resistance were compared.

[0067] The growth curves of RB cells and RB / CBP drug-resistant cells are as Figure 6 shown; the left figure is the growth curve of RB cells; the right figure is the growth curve of RB / CBP drug-resistant cells; as shown in the figure, starting from 12 h, with the extension of the culture time, the proliferation ability of the two groups of cells gradually increased, but the proliferation ability of RB / CBP drug-resistant cells was significantly lower than that of RB cells. Compared with RB cells, RB / CBP drug-resistant cells grew more slowly, the highest cell concentration decreased, and the time to reach the peak cell concentration was delayed (the time to reach the peak cell concentration of RB cells was 48 h, and the time to reach the peak cell concentration of RB / CBP drug-resistant cells was 72 h). The above results indicate that the proliferation ability of carboplatin-resistant RB cells decreased, and the main pathways of their recurrence or metastasis may not occur through cell proliferation.

[0068] 3. Determination of drug sensitivity and multidrug resistance of CBP / RB drug-resistant cells

[0069] The CCK-8 method was used to detect the sensitivity of RB cells and RB / CBP drug-resistant cells to carboplatin, etoposide, and vincristine, respectively. The specific steps are as follows:

[0070] RB cells in the logarithmic growth phase were seeded in 96-well plates, with 5×10 3 cells per well. Equal volumes of carboplatin solutions with gradient concentrations (50 μM, 100 μM, 200 μM, 300 μM, 400 μM) were added respectively. After culturing for 24 h, the absorbance value (OD) of each well was measured.

[0071] RB / CBP drug-resistant cells in the logarithmic growth phase were taken, with 5×10 3 cells per well. Equal volumes of carboplatin solutions with gradient concentrations (100 μM, 200 μM, 400 μM, 800 μM, 1000 μM) were added respectively. After culturing for 24 h, the absorbance value (OD) of each well was measured.

[0072] Tumor cell survival rate (%) = absorbance of experimental well (OD) / absorbance of control well (OD) × 100%, and the half-maximal inhibitory concentration (IC50) was calculated; the resistance index (RI) of RB / CBP drug-resistant cells to carboplatin = IC50 (RB / CBP drug-resistant cells) / IC50 (RB cells).

[0073] According to the above steps, etoposide solutions or vincristine solutions with gradient concentrations were prepared with etoposide (Vepeside, VP) or vincristine (Vincristine, VCR), and were added to equal amounts of RB cells or RB / CBP drug-resistant cells in the logarithmic growth phase respectively. After culturing for 24 h, the absorbance value (OD) of each well was measured. The IC50 and resistance index RI of etoposide and vincristine to RB cells and CBP / RB drug-resistant cells were calculated.

[0074] The inhibitory effects of carboplatin, etoposide, and vincristine on RB cells and RB / CBP-resistant cells are as Figure 7 shown. Among them, the abscissa represents the concentration of the drug solution, and the ordinate represents the survival rate of tumor cells; a is the inhibitory effect of carboplatin on RB cells; b is the inhibitory effect of carboplatin on RB / CBP-resistant cells; c is the inhibitory effect of etoposide on RB cells; d is the inhibitory effect of etoposide on RB / CBP-resistant cells; e is the inhibitory effect of vincristine on RB cells; f is the inhibitory effect of vincristine on RB / CBP-resistant cells.

[0075] The drug resistance of RB / CBP-resistant cells to carboplatin, etoposide, and vincristine is shown in Table 1.

[0076] Table 1 Comparison of drug resistance between RB cells and RB / CBP-resistant cells

[0077]

[0078] According to the drug resistance judgment criteria (drug resistance index RI < 5 is low drug resistance, 5 - 15 is moderate drug resistance, > 15 is high drug resistance), it can be seen that RB / CBP-resistant cells are moderately resistant to etoposide and vincristine and are lowly resistant to CBP. Thus, it can be concluded that RB / CBP-resistant cells show significant multi-drug resistance after being stimulated by gradient concentrations of carboplatin at intervals for up to 6 months.

[0079] 4. Inhibitory effect of honokiol on RB / CBP-resistant cells

[0080] The inhibitory effect of HNK on RB / CBP-resistant cells was determined by the CCK-8 method.

[0081] RB / CBP-resistant cells in the logarithmic growth phase were seeded in 96-well plates at 5×10 3 cells per well. In the experimental groups, equal volumes of HNK solutions with final concentrations of 30 μM, 40 μM, and 50 μM were added respectively, and in the control group, an equal volume of DMSO solvent was used as a control. After culturing for 24 h and 48 h respectively, the absorbance value (OD) of each well was measured. The inhibitory effects of different concentrations of HNK on RB / CBP-resistant cells are as Figure 8 shown.

[0082] Figure 8 are the inhibitory effects of HNK at different concentrations and different time points on RB / CBP-resistant cells; the left figure shows the inhibitory effects of different concentrations of HNK on RB / CBP-resistant cells after culturing for 24 h; the right figure shows the inhibitory effects of different concentrations of HNK on RB / CBP-resistant cells after culturing for 48 h.

[0083] As can be seen from the figure, with the increase of HNK concentration, the inhibition rate of RB / CBP drug-resistant cells increased significantly. The research results showed that different concentrations of HNK (30 μM, 40 μM, 50 μM) could inhibit the proliferation of RB / CBP drug-resistant cells to varying degrees (P < 0.001), and with the increase of HNK concentration and the prolongation of culture time, the inhibitory effect was enhanced. Thus, it can be seen that HNK still maintained good sensitivity to RB / CBP drug-resistant cells, and the inhibitory intensity on RB / CBP drug-resistant cells was similar to that of RB non-drug-resistant cells.

[0084] In summary, this application first discovered the new effect of honokiol in the treatment of RB, which can effectively inhibit the proliferation of RB cells, and is of great significance for the development of new therapeutic drugs for RB. It can be seen from Test Example 1 that honokiol can significantly inhibit the proliferation of RB cells, and with the increase of honokiol drug concentration and the prolongation of the inhibition time, the survival rate of RB cells continuously decreases, showing dose and time dependence. Honokiol can inhibit the proliferation of RB cells by promoting apoptosis and inducing cell cycle arrest.

[0085] This study also first found that honokiol has a significant therapeutic effect on multi-drug resistant RB cells, providing a new idea for solving the clinical problem of RB chemotherapy drug resistance. Chemotherapy is an important treatment method for RB, but multi-drug resistance in chemotherapy is the main obstacle in clinical treatment and an important cause of chemotherapy failure. It can be seen from Test Example 2 that by stimulating RB cells intermittently with gradient concentrations of carboplatin for up to 6 months, multi-drug resistant RB cells were successfully constructed. Through experiments, it was proved that honokiol still maintained good sensitivity to RB drug-resistant cells, and the killing effect on RB / CBP drug-resistant cells was similar to that of RB non-drug-resistant cells.

[0086] Obviously, the above embodiments are only examples clearly described and not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation manners here. And the obvious changes or modifications derived therefrom are still within the protection scope of this application.

Claims

1. Use of honokiol in the preparation of a drug for treating carboplatin-resistant retinoblastoma, characterized in that, The structural formula of the honokiol is as follows:

2. The application according to claim 1, characterized in that The drug is a drug that has an inhibitory effect on human retinoblastoma cells.

3. The application according to claim 2, wherein The drug has the effect of inducing apoptosis of human retinoblastoma cells.

4. The application according to claim 3, characterized in that, The drug has the effect of up-regulating the expression of caspase-3 in human retinoblastoma cells.

5. The application according to claim 3, characterized in that, The drug has the effect of down-regulating the expression of survivin in human retinoblastoma cells.

6. The application according to claim 3, characterized in that The drug has the effect of inducing cell cycle arrest in human retinoblastoma cells.

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