阅读说明：本技术 一种靶向卵泡刺激素受体的肿瘤成像与治疗探针及其制备方法与应用 (Tumor imaging and treating probe targeting follicle-stimulating hormone receptor, and preparation method and application thereof ) 是由 石梅 张晓燕 周晓波 刘齐雨 李富友 李小平 徐丛剑 于 2020-12-14 设计创作，主要内容包括：为了解决术中准确识别病灶,在近红外荧光染料用于显像优势的基础上,增加其特异性显像。本发明提供一种靶向卵泡刺激素受体的肿瘤成像与治疗探针及其制备方法。本发明由卵泡刺激素多肽(LYTRDLVYKDPARPKIQKTCTF)与近红外荧光染料Rh760偶联而成卵泡刺激素受体靶向的肿瘤成像与治疗探针FSH-Rh760,优点是,本发明利用FSHR在卵巢癌中高表达,基于FSH多肽与FSHR特异性结合的原理,靶向识别卵巢癌细胞。利用近红外荧光染料Rh760穿透深度更深、背景信号更低的优点,在荧光成像和荧光指导手术中有良好的应用前景。本发明的靶向探针FSH-Rh760可用于卵巢癌的光热治疗,作为手术治疗的补充,改善卵巢癌预后。(In order to solve the problem of accurate identification of the focus in the operation, the specific imaging of the focus is increased on the basis of the advantage of using near infrared fluorescent dye for imaging. The invention provides a tumor imaging and treating probe targeting a follicle-stimulating hormone receptor and a preparation method thereof. The follicle-stimulating hormone receptor targeted tumor imaging and treatment probe FSH-Rh760 is formed by coupling follicle-stimulating hormone polypeptide (LYTRDLVYKDPARPKIQKTCTF) and near-infrared fluorescent dye Rh760, and the ovarian cancer cell targeted identification method has the advantages that FSHR is highly expressed in ovarian cancer, and ovarian cancer cells are targeted and identified based on the principle that FSHR is specifically combined with FSHR. The advantages of deeper penetration depth and lower background signal of the near-infrared fluorescent dye Rh760 are utilized, and the method has good application prospect in fluorescence imaging and fluorescence guided surgery. The targeting probe FSH-Rh760 can be used for photothermal therapy of ovarian cancer, and can be used as a supplement of surgical therapy to improve the prognosis of ovarian cancer.)

1. A follicle-stimulating hormone receptor targeted tumor imaging and therapy probe FSH-Rh760 has a structural formula as follows:

。

2. the method for preparing FSH-Rh760 as a follicle stimulating hormone receptor-targeted tumor imaging and therapy probe according to claim 1, which is formed by coupling follicle stimulating hormone polypeptide (LYTRDLVYKDPARPKIQKTCTF) with near-infrared fluorescent dye Rh760, and comprises the following steps:

(1) adding 0.2 mmol of compound Rh760, 100 mg of Katt condensation reagent, 150 mg of piperazine and 10 mL of dichloromethane solution into a 50 mL round-bottom flask, stirring at room temperature for reaction for 2 hours, removing the solvent by reduced pressure distillation after the reaction is finished, and purifying and separating by column chromatography by using dichloromethane and methanol as eluent to obtain 105 mg of compound Rh 760-Paz;

(2) adding 0.2 mmol of compound Rh760-Paz, 86 mg of glutaric anhydride and 20 mL of dichloromethane solution into a 50 mL round-bottom flask, stirring at room temperature for reaction for 2 hours, removing the solvent by reduced pressure distillation after the reaction is finished, and purifying and separating by column chromatography by using dichloromethane and methanol as eluent to obtain 150 mg of compound Rh 760-GA;

(3) the FSH polypeptide sequence is LYTRDLVYKDPARPKIQKTCTF, 0.5 g of 2-cl resin is weighed, 4 ml of DCM is added for soaking for 5 min, DMF is used for washing for 2 times, 0.2 mmol of Fmoc-D-Tyr (tbu) -OH, 6 ml of DCM and 0.5 ml of DIEA are added for reaction for 90 min, 0.5 ml of analytical methanol and 1 ml of DCM are added after the reaction is finished, and the reaction is blocked for 20 min; washing with DMF for 4 times, adding 20% piperidine and 80% piperidine for reaction for 20 min to remove Fmoc, washing with DMF for 5 times, taking 10-20 particles of resin, adding 2 drops of ninhydrin and 2 drops of pyridine, and developing at 100 ℃ for 2 min; ③ weighing 0.45 mmol of amino acid Fmoc-D-Thr (tbu) -oh and 0.45 mmol of HOBT, adding 5 ml of DMF and 0.5 ml of DIC for reaction for 1 h, washing with DMF for 4 times, taking about 30 resin particles for detection, and obtaining colorless product;

(4) repeating the steps 2 and 3 until the end of peptide chain coupling, removing Fmoc, and coupling RH760-GA, wherein the method is the same as the step 3;

(5) the resin was drained with methanol and 10 addedml is composed of 95% TFa, 1% H₂And (3) shaking and cutting the cutting fluid consisting of O, 2% EDT and 2% TIS for 2h, settling the obtained reaction solution by using 40 ml of ethyl glacial ether to obtain a blue-green solid, and separating, purifying and freeze-drying by HPLC (high performance liquid chromatography) to obtain a blue-green solid product.

3. Use of the probe FSH-Rh760 according to claim 1 for targeted imaging and therapy of follicle stimulating hormone receptors.

Technical Field

The invention relates to a tumor imaging and treating probe targeted by a follicle-stimulating hormone receptor, and a preparation method and application thereof.

Background

Ovarian cancer mortality is at the head of female reproductive system malignancies. In 87% of cases, the survival rate is only 15% after 10 years, which is already advanced (stages III and IV). Tumor debulking in combination with chemotherapy is the primary treatment modality for advanced ovarian cancer. The thoroughness of the surgery is closely related to the prognosis of ovarian cancer. Accurate identification of lesions is critical in the procedure to achieve complete resection. The existing imaging examination such as ultrasound, X-ray, CT, MRI and the like is tumor nonspecific imaging and is difficult to be used for real-time imaging in operation. The fluorescence guided surgery uses a tumor targeted imaging probe, is specifically combined with tumor cells and labeled, and guides the excision of a focus in an intraoperative real-time fluorescence imaging mode. The tumor targeting probe consists of a targeting group and a fluorescent probe, wherein the targeting group determines the imaging specificity, and the fluorescent probe needs to have good penetrability and stability.

The ovary is regulated by hypothalamic-pituitary-ovarian axis related hormones, such as Follicle Stimulating Hormone (FSH). Under physiological conditions, Follicle-stimulating hormone receptor (FSHR) is mainly expressed in ovary and has high specificity. Ovarian cancer is also closely related to hypothalamic-pituitary-ovarian axis hormones, with FSHR expression rates of approximately 50-60% in ovarian cancer. Ovarian cancer targeted therapy with FSHR as a target has been advanced, so FSHR is expected to become a target for specific imaging of ovarian cancer.

FSH polypeptides that bind specifically to FSHR may be used as targeting groups for imaging probes. The short peptide is a common targeting strategy and has mature application in tumor targeting therapy, and the research on tumor targeting imaging is gradually increased. Compared with monoclonal antibody, the short peptide has the advantages of weak immunogenicity, rapid in vivo distribution, simple synthesis, easy modification and the like. Tumor targeted imaging probes based on small molecule polypeptides have entered clinical trials.

Compared with the traditional imaging mode, Near infrared fluorescence (NIR) imaging has the characteristics of real time and rapidness, and the Near infrared fluorescent dye has the advantages of deeper penetration depth and lower background signal, and is more suitable for intraoperative imaging. However, the near-infrared fluorescent dye cannot be specifically combined with tumor cells, and the false positive rate of indocyanine green for ovarian cancer imaging is reported to reach 62%. The near-infrared fluorescent dye Rh760 has high luminous efficiency in a near-infrared band, and the molecule is electrically neutral, compared with most of near-infrared fluorescent dyes with positive charges or negative charges, the electrically neutral characteristic can avoid electrostatic interaction with other molecules in biological tissues to a greater extent, so that the influence of the introduction of dye molecules on the targeting property of polypeptide molecules is weakened.

Disclosure of Invention

In order to solve the problem of accurate identification of the focus in the operation, the specific imaging of the focus is increased on the basis of the advantage of using near infrared fluorescent dye for imaging. The invention provides a tumor imaging and treating probe targeting a follicle-stimulating hormone receptor and a preparation method thereof.

The invention is a follicle-stimulating hormone receptor targeted tumor imaging and treatment probe FSH-Rh760 formed by coupling follicle-stimulating hormone polypeptide (LYTRDLVYKDPARPKIQKTCTF) and near-infrared fluorescent dye Rh760, and the structural formula is as follows:

。

the preparation method of the follicle-stimulating hormone receptor targeted tumor imaging and treatment probe FSH-Rh760 comprises the following steps:

(1) a solution of 0.2 mmol of the compound Rh760, 100 mg (0.25 mmol) of the kat condensation reagent, 150 mg (1 mmol) of piperazine and 10 mL of dichloromethane was added to a 50 mL round bottom flask, and the reaction was stirred at room temperature for 2 hours, after the reaction was completed, the solvent was distilled off under reduced pressure, and the compound Rh760-Paz (105 mg) was isolated by column chromatography purification using dichloromethane and methanol as eluents, with the yield: 80 percent;¹H NMR (400 MHz, DMSO-d6, δ) 8.99 (bs, 1H), 7.62 (m, 2H), 7.53 (d, J = 8.4 Hz, 1H), 7.35 (d, J = 8.4 Hz, 1H), 6.76 (dd, J = 9.2 Hz, J = 2.4 Hz, 1H), 6.71 (d, J = 9.2 Hz, 1H), 6.62 (d, J = 2.4 Hz, 1H), 3.45 (q, J = 13.6 Hz, 4H), 3.15-3.45 (m, 6H), 2.2-2.6 (m, 8H), 2.0-2.30 (m, 2H), 1.60 (s, 6H), 1.14 (t, J = 7.2 Hz, 6H)；

(2) 0.2 mmol of the compound Rh760-Paz, 86 mg (10 mmol) of glutaric anhydride and 20 mL of dichloromethane solution were added to a 50 mL round-bottomed flask, and the reaction was stirred at room temperature for 2 hours, after the completion of the reaction, the solvent was distilled off under reduced pressure, and the compound Rh760-GA (150 mg) was isolated by column chromatography purification using dichloromethane and methanol as eluents, in yield: 95 percent;¹H NMR (400 MHz, DMSO-d6, δ) 8.99 (bs, 1H), 7.62 (m, 2H), 7.53 (d, J = 8.4 Hz, 1H), 7.35 (d, J = 8.4 Hz, 1H), 6.76 (dd, J = 9.2 Hz, J = 2.4 Hz, 1H), 6.71 (d, J = 9.2 Hz, 1H), 6.62 (d, J = 2.4 Hz, 1H), 3.45 (q, J = 13.6 Hz, 4H), 3.15-3.45 (m, 6H), 2.2-2.6 (m, 8H), 2.0-2.30 (m, 2H), 1.60 (s, 6H), 1.14 (t, J = 7.2 Hz, 6H)；

(3) the FSH polypeptide sequence is LYTRDLVYKDPARPKIQKTCTF, 0.5 g of 2-cl resin is weighed, 4 ml of DCM is added for soaking for 5 min, DMF is used for washing for 2 times, 0.2 mmol of Fmoc-D-Tyr (tbu) -OH, 6 ml of DCM and 0.5 ml of DIEA are added for reaction for 90 min, 0.5 ml of analytical methanol and 1 ml of DCM are added after the reaction is finished, and the reaction is blocked for 20 min; ② washing with DMF for 4 times, adding piperidine (20% piperidine +80% DMF) for reaction for 20 min to remove Fmoc, washing with DMF for 5 times, taking a small amount of resin (10-20 particles), adding ninhydrin (5 g/100ml analytical ethanol) 2 drops and pyridine 2 drops, and developing at 100 ℃ for 2 min; ③ weighing the next amino acid Fmoc-D-Thr (tbu) -oh (0.45 mmol) + HOBT (0.45 mmol), adding 5 ml DMF and 0.5 ml DIC for reaction for 1 h, washing with DMF for 4 times, taking a small amount of resin (about 30 particles), and detecting to obtain colorless product; fourthly, repeating the third step and the fourth step until the peptide chain coupling is finished, removing Fmoc, and coupling RH760-GA, wherein the method is the same as the third step; fifthly, the resin is pumped to dryness by methanol, 10 ml of cutting fluid (95 percent TFa +1 percent H) is added₂O +2% EDT +2% TIS) for 2h, precipitating the obtained reaction solution with 40 ml of ethyl glacial ether to obtain a blue-green solid, and separating, purifying and freeze-drying by HPLC to obtain a blue-green solid product.

The present invention is applicable to:

(1) based on the photothermal conversion characteristic of Rh760, the compound can be effectively used for treating cancer lesions by infrared illumination;

(2) based on the characteristics that the therapeutic probe FSH-Rh760 recognizes tumor cells in vivo and the near-infrared fluorescent dye Rh760 has deeper penetration depth and lower background signal, the fluorescent probe FSH-Rh760 can be effectively used in fluorescence imaging and fluorescence guided surgery.

The invention detects the binding capacity of the probe and ovarian cancer cells in a cell line, and the result shows that the binding capacity of the targeting probe FSH-Rh760 is stronger than that of Rh 760. The in-vivo imaging capability of the probe is detected by using a nude mouse abdominal cavity tumor implantation model, and the result shows that the targeting probe FSH-Rh760 can be specifically combined with an abdominal cavity metastasis, and the effect is superior to that of Rh 760. The photothermal treatment effect of the probe is evaluated by using a nude mouse abdominal cavity tumor implantation model, and the number of abdominal cavity transfer foci of the targeted probe FSH-Rh760 photothermal treatment group is obviously reduced compared with that of a control group.

The invention has the advantages that:

1. the ovarian cancer cell targeted recognition method utilizes high FSHR expression in ovarian cancer and is based on the principle that FSHR is specifically combined with FSHR.

2. The invention has good application prospect in fluorescence imaging and fluorescence guiding operation by utilizing the advantages of deeper penetration depth and lower background signal of the near-infrared fluorescent dye Rh 760.

3. The targeting probe FSH-Rh760 can be used for photothermal therapy of ovarian cancer, and can be used as a supplement of surgical therapy to improve the prognosis of ovarian cancer.

The invention can identify ovarian cancer cells and focus of FSHR in vivo and in vitro in a targeted manner, well distinguish the ovarian cancer implantation metastasis, intestinal canal and other normal tissues, and the preoperative photothermal treatment can reduce the focus and is beneficial to improving the surgical resection rate; photothermal therapy is applied to the focus which is difficult to excise after the operation, so that the tumor load can be reduced, and the prognosis can be improved. On the basis of specific identification of ovarian cancer focuses by the FSH-Rh760 probe, the photothermal conversion property of the ovarian cancer focus is further utilized to carry out photothermal treatment and kill tumor cells.

Drawings

FIG. 1 synthetic route to FSH-Rh760 probe;

FIG. 2 UV absorption and fluorescence spectra of FSH-Rh760 and Rh 760;

FIG. 3 binding of FSH-Rh760 to ovarian cancer cells;

FIG. 4 FSH-Rh760 for imaging of ovarian cancer abdominal metastases in nude mice;

FIG. 5 temperature ramp curves for FSH-Rh760 photothermal therapy;

FIG. 6 FSH-Rh760 for photothermal treatment of ovarian cancer abdominal metastases in nude mice.

Detailed Description

The invention provides a novel FSH receptor-targeted tumor imaging and treatment probe FSH-Rh760, which is formed by coupling FSH polypeptide and a near-infrared fluorescent dye Rh 760.

The specific embodiment for preparing the near-infrared fluorescent probe is as follows:

(1) a solution of 0.2 mmol of Rh760, 100 mg (0.25 mmol) of Katt condensation reagent, 150 mg (1 mmol) of piperazine and 10 mL of dichloromethane was charged in a 50 mL round-bottomed flask, and the reaction was stirred at room temperature for 2 hours, after completion of the reaction, the solvent was distilled off under reduced pressure, and the compound Rh760-Paz (105 mg) was isolated by column chromatography using dichloromethane and methanol as eluents. Yield: 80 percent.¹H NMR (400 MHz, DMSO-d6, δ) 8.99 (bs, 1H), 7.62 (m, 2H), 7.53 (d, J = 8.4 Hz, 1H), 7.35 (d, J = 8.4 Hz, 1H), 6.76 (dd, J = 9.2 Hz, J = 2.4 Hz, 1H), 6.71 (d, J = 9.2 Hz, 1H), 6.62 (d, J = 2.4 Hz, 1H), 3.45 (q, J = 13.6 Hz, 4H), 3.15-3.45 (m, 6H), 2.2-2.6 (m, 8H), 2.0-2.30 (m, 2H), 1.60 (s, 6H), 1.14 (t, J = 7.2 Hz, 6H)。

(2) A solution of 0.2 mmol of the compound Rh760-Paz, 86 mg (10 mmol) of glutaric anhydride and 20 mL of dichloromethane was added to a 50 mL round-bottomed flask, and the reaction was stirred at room temperature for 2 hours, after completion of the reaction, the solvent was distilled off under reduced pressure, and the compound Rh760-GA (150 mg) was isolated by column chromatography using dichloromethane and methanol as eluents. Yield: 95 percent.¹H NMR (400 MHz, DMSO-d6, δ) 8.99 (bs, 1H), 7.62 (m, 2H), 7.53 (d, J = 8.4 Hz, 1H), 7.35 (d, J = 8.4 Hz, 1H), 6.76 (dd, J = 9.2 Hz, J = 2.4 Hz, 1H), 6.71 (d, J = 9.2 Hz, 1H), 6.62 (d, J = 2.4 Hz, 1H), 3.45 (q, J = 13.6 Hz, 4H), 3.15-3.45 (m, 6H), 2.2-2.6 (m, 8H), 2.0-2.30 (m, 2H), 1.60 (s, 6H), 1.14 (t, J = 7.2 Hz, 6H)。

(3) The FSH polypeptide sequence is LYTRDLVYKDPARPKIQKTCTF. Weighing 0.5 g of 2-cl resin, adding 4 ml of DCM to soak for 5 min, washing with DMF for 2 times, adding 0.2 mmol of Fmoc-D-Tyr (tbu) -OH, 6 ml of DCM and 0.5 ml of DIEA, and reacting for 90 min. After the reaction, 0.5 ml of analytical methanol and 1 ml of DCM were added, and the reaction was stopped for 20 min. ② washing with DMF for 4 times, adding piperidine (20% piperidine +80% DMF) to react for 20 min to remove Fmoc. Washing with DMF for 5 times, collecting small amount of resin (10-20 granules), adding ninhydrin (5 g/100ml analytical ethanol) 2 drops and pyridine 2 drops, and developing at 100 deg.C for 2 min. (iii) weighing downOne amino acid Fmoc-D-Thr (tbu) -oh (0.45 mmol) + HOBT (0.45 mmol), 5 ml DMF, 0.5 ml DIC were added for 1 h, washed 4 times with DMF, and a small amount of resin (about 30 particles) was detected as colorless. Fourthly, repeating the third step and the fourth step until the peptide chain coupling is finished, removing Fmoc, and coupling RH 760-GA. Fifthly, the resin is pumped to dryness by methanol, 10 ml of cutting fluid (95 percent TFa +1 percent H) is added₂O +2% EDT +2% TIS) was cut with shaking for 2 h. The resulting reaction solution was precipitated with 40 ml of ethyl acetate to obtain a blue-green solid. Separating by HPLC, purifying, and lyophilizing to obtain blue-green solid product. The synthetic route of FSH-Rh760 is shown in FIG. 1.

FSH-Rh760 and Rh760 solutions (solvent DMSO) were prepared at a concentration of 2. mu.M, and the UV absorption spectrum of the probe was detected using a spectrophotometer, and the fluorescence spectrum of the probe was detected using a fluorescence spectrometer, as shown in FIG. 2.

The specific implementation mode of the near-infrared fluorescent probe for targeted imaging and treatment of ovarian cancer is as follows:

human ovarian carcinoma cell line A2780, IGROV1 (high expression FSHR) and human ovarian carcinoma cell line SKOV3 (low expression FSHR) in logarithmic growth phase at 2X10³One/well was seeded on chamber slides and the experiment was started with 50% confluency of cells. The culture medium was aspirated off, 10. mu.M FSH-Rh760 and Rh760 were added, respectively, and incubation was carried out at 37 ℃ for 90 min. The supernatant was aspirated and washed 3 times with PBS. Fixation with 4% paraformaldehyde at room temperature for 10 min. The fixative was aspirated and washed 1 time with PBS. Cell membrane dye WGA488 was added and incubated for 10 min at room temperature. Cell membrane dye was aspirated and washed 3 times with PBS. The slides were mounted with fluorescent mounting tablets containing DAPI and observed under confocal microscopy. The fluorescence intensity of the targeting probe FSH-Rh760 is higher than that of Rh760, and the fluorescence intensity of the cells A2780 and IGROV1 with high FSHR expression is higher than that of the cells SKOV3 with low FSHR expression (figure 3). Cell experiment results show that the binding force of the targeting probe FSH-Rh760 to ovarian cancer cells expressing FSHR is stronger than that of Rh 760.

Digesting a human ovarian cancer cell line A2780-Luc (transfection Luciferase gene) to prepare single cell suspension, and adding the single cell suspension into each cell at a ratio of 1x10⁷200 ul was inoculated into the abdominal cavity of female nude mice. The tumor cells are sown and grown in the abdominal cavity, and after 2 weeks, the number of the planted foci can exceed 10, and the size is about 0.1-1 cm. The tumor-bearing mice of the experimental group are injected with 60 mug (3 mg/kg) of targeting probe FSH-Rh760 in the abdominal cavity, and the tumor-bearing mice of the control group are injected with 10.4 mug (0.52 mg/kg) of control probe Rh760 in the abdominal cavity. The mice were sacrificed 2h after injection of the imaging probe, the abdominal cavity was opened for simultaneous near-infrared fluorescence imaging and bioluminescence imaging (excitation wavelength 740 nm, emission wavelength 790 nm), and the bioluminescence signal was compared with the fluorescence signal. The targeting probe FSH-Rh760 has an obvious signal in an abdominal cavity implanting range, and a fluorescent signal is consistent with a bioluminescent signal; the control probe Rh760 signal was concentrated in the liver and was not imaged at the tumor foci (fig. 4). The imaging result of the nude mouse abdominal cavity tumor implantation model indicates that the targeting probe FSH-Rh760 can specifically identify ovarian cancer metastasis.

Digesting human ovarian cancer cell line A2780 to prepare single cell suspension, and adding each single cell suspension at a ratio of 1x10⁷200 ul was inoculated into the abdominal cavity of female nude mice. Tumor-bearing mice were randomly divided into 6 groups (5 per group): FSH-Rh760+ laser group, PBS + laser group, FSH-Rh760 group, Rh760 group and PBS group. 7 days after cell inoculation, 3 groups of mice receiving photothermal therapy were irradiated with laser once every 3 days for 4 times; the 3 groups of mice corresponding to the mice were not irradiated with laser, and the other treatments were not changed. 3 groups of mice receiving photothermal therapy: the mice in the experimental group are injected with 120 mug (6 mg/kg) of targeting probe FSH-Rh760 in the abdominal cavity, and the mice in the control group are injected with 20.8 mug (1.04 mg/kg) of control probe Rh760 in the abdominal cavity or PBS solution with the same volume. Irradiating the whole abdomen of the tumor-bearing mouse with near infrared fluorescent light source 2h after injecting the imaging probe, wherein the excitation light wavelength is 808 nm, and the power density is 1.60W/cm²The irradiation time was 10 min. The abdominal body temperature change of the mice under laser irradiation is monitored by a thermal imaging camera, and the temperature rise curves of the mice of the experimental group and the control group are shown in figure 5. Mice were sacrificed 19 days after cell inoculation and the number of ovarian cancer metastases in the abdominal cavity was counted. The results showed that the number of metastases was significantly reduced in the FSH-Rh760 photothermal treatment group compared to the other 5 groups (fig. 6), indicating that the FSH-Rh760 photothermal treatment, which is a targeting probe, was effective in reducing the number of ovarian cancer metastases.