生长抑素受体介导的放射性核素治疗

生长抑素受体介导的放射性核素治疗(peptide receptor radionuclide therapy,PRRT)是用于不能手术治疗或有远处转移的胃、肠和胰腺等神经内分泌肿瘤病人的一种新型治疗方法,本文旨在综述近年来不同核素标记生长抑素类似物的临床评价及相关研究。     

溶瘤病毒靶向治疗肿瘤的策略

近年来,随着国内外几款溶瘤病毒制剂的相继上市,溶瘤病毒疗法成为肿瘤免疫治疗的焦点。溶瘤病毒可选择性感染并裂解肿瘤细胞,同时释放肿瘤相关抗原激活机体的抗肿瘤免疫反应,达到杀伤肿瘤细胞和抑制肿瘤生长的目的。溶瘤病毒对肿瘤的靶向杀伤作用决定了其安全性和溶瘤效果。为了开发出安全高效的溶瘤病毒,目前主要采用以下策略：利用某些病毒载体对肿瘤细胞的天然靶向性,使溶瘤病毒选择性地在肿瘤细胞内复制并杀伤肿瘤细胞;或者对病毒基因组进行缺失和插入等修饰,通过靶向肿瘤细胞特异性表面受体、胞内信号通路或者肿瘤微环境等提高溶瘤病毒的肿瘤靶向性。其中,肿瘤微环境中的低氧状态、新血管生成以及免疫抑制状态等都可成为溶瘤病毒的靶点。而溶瘤病毒通过表达细胞因子和免疫检查点抑制剂,或者与CAR-T细胞联合作用,靶向调节肿瘤微环境中免疫抑制状态,成为提高溶瘤病毒肿瘤靶向性的常用方法。本文将对以上溶瘤病毒靶向治疗肿瘤策略的研究进展进行综述。     

JNM:科学家或有望开发出抵御多种癌症的新型疗法

正近日,一项刊登在国际杂志The Journal of Nuclear Medicine上的研究报告中,来自澳大利亚的研究人员通过研究阐明了靶向作用生长抑素受体的肽类受体放射性核素疗法在治疗除神经内分泌瘤(NETs)之外的其它恶性肿瘤上的潜能;研究者表示,将FDA批准的诊断显像剂Netspot与实验性药物Lutathera相互配对或许就能够明显改善生长抑素受体阳性的NETs患者的无进展生存率。     

生长抑素受体在人神经内分泌癌组织中的表达及受体激活对细胞生长的抑制

生长抑素（somatostatin,SST）通过与细胞膜上的G蛋白偶联的生长抑素受体（somatostatin receptors,SSTRs）结合而发挥其抑制细胞增殖的作用,因而生长抑素类似物（somatostatin analogue, SSA）常被用于肿瘤辅助治疗。然而,治疗效果存在相当大的个体差异,推测生长抑素类似物治疗效果不佳,与内源性生长抑素受体表达缺失或者表达量和亚型组合有关。为此,检测各亚型SSTR在几例罕见的神经内分泌肿瘤中的表达,并检测过表达SSTR2和SSTR5以及受体激活对细胞增殖的抑制效果,分析受体激活的可能机制,有助于临床筛选适合SSA肿瘤辅助治疗的病例,预估SSA的治疗效果。免疫组化检测肿瘤组织SSTR1-5的表达。在培养的293T细胞中过表达SSTR2和SSTR5,免疫共沉淀检测受体相互作用,免疫荧光和共聚焦显微镜检测受体细胞内定位。用MTT法检测受体过表达及激活对培养的人肺癌细胞NCI-H460细胞增殖的影响,用流式细胞技术检测细胞周期分布。SSTR1-5在10例神经内分泌肿瘤组织中均有不同程度的表达,表达亚型及表达量与肿瘤类型和年龄无关,SSTR5在所有肿瘤组织中均表达。SSTR2与SSTR5可形成受体相互作用。SSTR2与SSTR5活化后相互作用增加并定位于细胞质。共表达SSTR2和SSTR5显著抑制细胞增殖,并与受体激活剂呈现剂量相关性。SSTR2/SSTR5的共表达及激活显著减少S期的细胞而滞留于G₁期。     

放射性药物在肿瘤靶向治疗中的应用

放射性药物指供临床诊断或治疗用的放射性核素制剂或其标记化合物。放射性核素靶向治疗是利用对肿瘤细胞具有特异高亲和力的分子载体将核素定向导入特定的肿瘤组织,对肿瘤进行治疗。与传统的放疗和化疗相比,其具有选择性杀伤肿瘤细胞的特点。随着核医学的发展,SPECT/CT、PET/CT的普及,新靶点的发现和新型放射性药物的研发,利用放射性药物进行靶向治疗在肿瘤临床治疗中占据的地位越来越重要。本文简述了放射性药物的分类、组成及特点;综述了针对肿瘤相关抗原的放射免疫药物在非霍奇金淋巴瘤、结直肠癌和前列腺癌中的应用;受体介导的放射性核素药物在治疗神经内分泌肿瘤、前列腺癌和乳腺癌中的临床应用以及基于基因修饰的放射性药物在肿瘤靶向治疗中的实验研究进展。最后总结了放射性药物在肿瘤靶向治疗中的应用前景与面临的挑战,以期为靶向治疗肿瘤的放射性药物的开发和临床应用提供一些参考。     

转铁蛋白受体——肿瘤的标志物和靶向治疗

转铁蛋白受体不仅介导细胞内铁的摄取和参与细胞生长调节,而且能够在肿瘤细胞表面高度表达,被认为是一种有效的肿瘤标志物,广泛应用于各类恶性肿瘤的靶向治疗。利用转铁蛋白或转铁蛋白受体的单克隆抗体与转铁蛋白受体的特异性结合作用,通过受体介导的内吞机制实现化疗药物、蛋白毒素或治疗性基因等的细胞摄入。随着对转铁蛋白受体的深入研究,靶向转铁蛋白受体的肿瘤药物将在基因治疗和跨血脑屏障运输等多方面得到进一步应用。     

溶瘤病毒的免疫学机制及临床研究进展

溶瘤病毒（oncolytic virus,OVs）历经百年发展,应用于当前最具潜力的肿瘤免疫疗法。它主要是天然的或基因修饰的DNA病毒和RNA病毒。近年来随着基因工程技术的飞跃发展,经基因改造的溶瘤病毒在肿瘤治疗领域取得很大进展,很多不同类型的病毒（包括单纯疱疹病毒、腺病毒、痘病毒、麻疹病毒和呼肠孤病毒等）正处于临床前研究、临床试验阶段或已批准上市,显示了良好的安全性和临床疗效。普遍认为溶瘤病毒靶向杀伤肿瘤细胞是通过选择性在肿瘤细胞内自我复制,最终裂解肿瘤细胞,同时可激发机体的免疫应答反应,进而增强抗肿瘤免疫效果,靶向杀伤肿瘤细胞而对正常细胞无明显影响。运用基因重组技术将溶瘤病毒与免疫检查点相结合以及肿瘤免疫联合疗法的兴起和不断进步,使溶瘤病毒的应用更加广泛,但仍存在病毒靶向性、安全性、给药途径等瓶颈问题。本文综述了溶瘤病毒的发展史、病毒分类、不同类型溶瘤病毒产品的临床研究进展、溶瘤病毒靶向杀伤肿瘤的免疫学机制及未来发展面临的挑战与展望等。     

溶瘤病毒在神经胶质瘤治疗中的研究进展

神经胶质瘤是增殖能力强、复发率高的原发性脑肿瘤,手术、放化疗等传统疗法效果较差,因此需要寻找更加有效的治疗方法。溶瘤病毒作为新型免疫疗法已被证明具有靶向性强、溶瘤效果显著及副作用少等优势。近年来溶瘤病毒在神经胶质瘤的临床治疗上取得一些突破性进展,其安全性和有效性得到了验证。现对近几年来溶瘤病毒单药治疗及与放化疗、免疫疗法等其他手段联合治疗神经胶质瘤的临床前研究和临床试验进展作详细介绍,对现阶段存在的问题进行讨论,并对未来研究进行展望。     

基于水疱性口炎病毒(VSV)的溶瘤病毒研究进展

溶瘤病毒利用肿瘤细胞抗病毒信号通路缺损或病毒受体过表达的特点,实现在其中选择性高复制进而杀伤肿瘤细胞,同时刺激机体产生特异性抗肿瘤免疫反应,是目前肿瘤治疗研究领域的热点。水疱性口炎病毒(vesicular stomatitis virus,VSV)能依赖肿瘤细胞干扰素信号通路的缺陷特异性靶向肿瘤细胞,具有复制高效、广泛组织嗜性、人群低致病性、基因组较小且易操纵等优势,是一种具有发展潜力的溶瘤病毒载体。对水疱性口炎病毒的病毒学特征以及目前基于VSV溶瘤病毒关于提高肿瘤选择性、延长半衰期、增强溶瘤效果的研究进展进行综述,为基于VSV溶瘤制剂的开发提供依据,为肿瘤治疗提供新的策略。     

溶瘤单纯疱疹病毒治疗技术及其进展

溶瘤病毒治疗是当前肿瘤治疗技术的研究热点,溶瘤单纯疱疹病毒是目前研究最多的,也是抗肿瘤作用最好的溶瘤病毒之一,本文就主要介绍溶瘤单纯疱疹病毒的优势、遗传操作、发展策略、研究进展及靶向性策略等。     

La radiothérapie interne vectorisée par les analogues de la somatostatine,en pratique,en 2019

Somatostatin receptors are overexpressed in differentiated gastroenteropancreatic neuroendocrine tumors (GEP-NET). Radiolabeled somatostatin analogs have been used for a few decades for imaging and more recently for peptide receptor radionuclide therapy (PRRT) in a theranostic approach. Medical access to PRRT has long been limited to a few European specialized medical centers despite promising results in large cohorts of patients. NETTER-1, a phase 3 randomized trial, has demonstrated a drastic improvement of midgut NET patients progression-free survival in PRRT arm as compared to somatostatin analogs, leading to marketing authorizations in USA and Europe. PRRT clinical availability is growing in France, with around 20 medical centers offering this innovative treatment for GEP-NET patients care in 2019. PPRT success-story should lead to improvements of radionuclide therapy developments, which will reshape our medical specialty to a more “clinically” practice. This review aims to detail PRRT in clinical practice in France in 2019, with emphasize on treatment indications, planning and practical aspects. Radioprotection aspects and future optimization perspectives will also be discussed.     

Somatostatin controls Kaposi's sarcoma tumor growth through inhibition of angiogenesis.

Somatostatin and its analogs are active in the inhibition of SST receptor-positive endocrine neoplasms, but their activity and mechanism in nonendocrine tumors is not clear. Somatostatin potently inhibited growth of a Kaposi's sarcoma xenograft in nude mice, yet in vitro the tumor cells did not express any known somatostatin receptors and were not growth inhibited by somatostatin. Histological examination revealed limited vascularization in the somatostatin-treated tumors as compared with the controls. Somatostatin was a potent inhibitor of angiogenesis in an in vivo assay. In vitro, somatostatin inhibited endothelial cell growth and invasion. Migration of monocytes, important mediators of the angiogenic cascade, was also inhibited by somatostatin. Both cells types expressed somatostatin receptor mRNAs. These data demonstrate that somatostatin is a potent antitumor angiogenesis compound directly affecting both endothelial and monocytic cells. The debated function of somatostatin in tumor treatment and the design of therapeutic protocols should be reexamined considering these data.     

Lung cancer and oncolytic virotherapy——enemy's enemy

Lung cancer is one of the malignant tumors that seriously threaten human health worldwide, while the covid-19 virus has become people's nightmare after the coronavirus pandemic. There are too many similarities between cancer cells and viruses, one of the most significant is that both of them are our enemies. The strategy to take the advantage of the virus to beat cancer cells is called Oncolytic virotherapy. When immunotherapy represented by immune checkpoint inhibitors has made remarkable breakthroughs in the clinical practice of lung cancer, the induction of antitumor immunity from immune cells gradually becomes a rapidly developing and promising strategy of cancer therapy. Oncolytic virotherapy is based on the same mechanisms that selectively kill tumor cells and induce systemic anti-tumor immunity, but still has a long way to go before it becomes a standard treatment for lung cancer. This article provides a comprehensive review of the latest progress in oncolytic virotherapy for lung cancer, including the specific mechanism of oncolytic virus therapy and the main types of oncolytic viruses, and the combination of oncolytic virotherapy and existing standard treatments. It aims to provide new insights and ideas on oncolytic virotherapy for lung cancer.     

Inhibition of human non-small cell lung cancers with a targeted cytotoxic somatostatin analog, AN-162

Human non-small cell lung cancers (NSCLCs) express receptors for somatostatin. The cytotoxic analog of somatostatin AN-162 (AEZS-124), consisting of doxorubicin linked to a somatostatin analog RC-121 binds to receptors for somatostatin and is targeted to tumors expressing these receptors. The aim of this study was to investigate the effect of targeted cytotoxic somatostatin analog AN-162 on a panel of human NSCLC cell lines (A549, H460, H838, H1299) in vitro (at 0.5–100 μM concentrations) and in vivo on H460 and H1299 NSCLCs xenografted into nude mice (at the dose of 2.5 μmol/kg, i.v., once a week). The expression of mRNA for somatostatin receptor subtypes was investigated by RT-PCR in cell lines and tumor tissues. Somatostatin receptor proteins were also characterized by ligand competition assay and Western blotting. AN-162 significantly decreased cell proliferation in vitro and tumor growth (p < 0.05 vs. all groups) of H460 and H1299 NSCLCs in vivo. Based on real-time PCR array data, AN-162 induced several apoptosis-related genes in vivo in both models. Our results suggest that cytotoxic somatostatin analog AN-162 (AEZS-124) should be considered for the further development of a therapy of patients with NSCLC.     

Somatostatin receptor imaging in the diagnosis and treatment of neuroendocrine tumors.

Somatostatin analogs are used in the control of hormonal hypersecretion and tumor growth of patients with acromegaly, islet cell carcinomas and carcinoids. Recently we showed that somatostatin receptor positive tumors can be visualized in vivo after the administration of radioactive isotope-labelled somatostatin analogs. Receptor imaging was positive in 18/21 islet cell tumors, 30/31 carcinoids, 26/28 paragangliomas, 9/14 medullary thyroid carcinomas, 5/7 small cell lung cancers, 6/7 neuroblastomas, 38/49 primary breast cancers, and 0/18 pancreatic adenocarcinomas. Also 11/11 meningiomas, 4/4 astrocytomas and 0/3 glioblastomas could be visualized. Somatostatin receptor imaging is an easy, harmless and painless diagnostic method. It is an in vivo method for the recognition of neuroendocrine cancers. It localizes multiple and/or metastatic tumors, predicts the successful control of hormonal hypersecretion by octreotide and seems of prognostic value in certain types of cancer. This scintigraphic method might help in patient selection for clinical trials with somatostatin analogs in the treatment of neuroendocrine cancers.     

Oncolytic virotherapy for cancer treatment: challenges and solutions

Advances in gene modification and viral therapy have led to the development of a variety of vectors in several viral families that are capable of replication specifically in tumor cells. Because of the nature of viral delivery, infection, and replication, this technology, oncolytic virotherapy, may prove valuable for treating cancer patients, especially those with inoperable tumors. Current limitations exist, however, for oncolytic virotherapy. They include the body's B and T cell responses, innate inflammatory reactions, host range, safety risks involved in using modified viruses as treatments, and the requirement that most currently available oncolytic viruses require local administration. Another important constraint is that genetically enhanced vectors may or may not adhere to their replication restrictions in long-term applications. Several solutions and strategies already exist, however, to minimize or circumvent many of these limitations, supporting viral oncolytic therapy as a viable option and powerful tool in the fight against cancer.     

Cancer cell specific cytotoxic gene expression mediated by ARF tumor suppressor promoter constructs

In current cancer treatment protocols, such as radiation and chemotherapy, side effects on normal cells are major obstacles to radical therapy. To avoid these side effects, a cancer cell-specific approach is needed. One way to specifically target cancer cells is to utilize a cancer specific promoter to express a cytotoxic gene (suicide gene therapy) or a viral gene required for viral replication (oncolytic virotherapy). For this purpose, the selected promoter should have minimal activity in normal cells to avoid side effects, and high activity in a wide variety of cancers to obtain optimal therapeutic efficacy.     

Oncosuppressive Suicide Gene Virotherapy “PVH1-yCD/5-FC” for Pancreatic Peritoneal Carcinomatosis Treatment: NFκB and Akt/PI3K Involvement

Peritoneal carcinomatosis is common in advanced pancreatic cancer. Despite current standard treatment, patients with this disease until recently were considered incurable. Cancer gene therapy using oncolytic viruses have generated much interest over the past few years. Here, we investigated a new gene directed enzyme prodrug therapy (GDEPT) approach for an oncosuppressive virotherapy strategy using parvovirus H1 (PV-H1) which preferentially replicates and kills malignant cells. Although, PV-H1 is not potent enough to destroy tumors, it represents an attractive vector for cancer gene therapy. We therefore sought to determine whether the suicide gene/prodrug system, yCD/5-FC could be rationally combined to PV-H1 augmenting its intrinsic oncolytic activity for pancreatic cancer prevention and treatment. We showed that the engineered recombinant parvovirus rPVH1-yCD with 5-FC treatment increased significantly the intrinsic cytotoxic effect and resulted in potent induction of apoptosis and tumor growth inhibition in chemosensitive and chemoresistant cells. Additionally, the suicide gene-expressing PV-H1 infection reduced significantly the constitutive activities of NFκB and Akt/PI3K. Combination of their pharmacological inhibitors (MG132 and {"type":"entrez-nucleotide","attrs":{"text":"LY294002","term_id":"1257998346","term_text":"LY294002"}}LY294002) with rPVH1-yCD/5-FC resulted in substantial increase of antitumor activity. In vivo, high and sustained expression of NS1 and yCD was observed in the disseminated tumor nodules and absent in normal tissues. Treatment of mice bearing intraperitoneal pancreatic carcinomatosis with rPVH1-yCD/5-FC resulted in a drastic inhibition of tumor cell spreading and subsequent increase in long-term survival. Together, the presented data show the improved oncolytic activity of wPV-H1 by yCD/5-FC and thus provides valuable effective and promising virotherapy strategy for prevention of tumor recurrence and treatment. In the light of this study, the suicide gene parvovirotherapy approach represents a new weapon in the war against pancreatic cancer. Moreover, these preliminary accomplishments are opening new field for future development of new combined targeted therapies to have a meaningful impact on advanced cancer.