TGF—β在前列腺癌骨转移中的研究进展

进展期前列腺癌多会发生骨转移,导致患者骨质破坏甚至死亡。前列腺癌发生骨转移的机制目前尚未研究清楚。既往多认为是因为前列腺癌细胞表面携带者容易在骨环境中生长的表型。但是目前多认为是肿瘤细胞与骨骼微环境之间的相互作用导致的结果。它们之间是通过细胞因子来传递信息。在众多因子中,TGF-β对前列腺癌骨转移灶中的各种细胞都起着重要作用。研究表明在体外实验中TGF-β的作用极易受到细胞生长环境的影响,表现出不同的功能。这提示着TGF-β信号通路和其他信号通路之间存在非常强的交互作用。本文的重点在于对TGF-β在前列腺癌骨转移中的作用研究进展进行综述,阐述TGF-β对转移灶中不同细胞的作用．为今后肿瘤的治疗研究寻找一个好的方向。     

TGF-β在前列腺癌骨转移中的研究进展

进展期前列腺癌多会发生骨转移,导致患者骨质破坏甚至死亡。前列腺癌发生骨转移的机制目前尚未研究清楚。既往多认为是因为前列腺癌细胞表面携带者容易在骨环境中生长的表型。但是目前多认为是肿瘤细胞与骨骼微环境之间的相互作用导致的结果。它们之间是通过细胞因子来传递信息。在众多因子中,TGF-β对前列腺癌骨转移灶中的各种细胞都起着重要作用。研究表明在体外实验中TGF-β的作用极易受到细胞生长环境的影响,表现出不同的功能。这提示着TGF-β信号通路和其他信号通路之间存在非常强的交互作用。本文的重点在于对TGF-β在前列腺癌骨转移中的作用研究进展进行综述,阐述TGF-β对转移灶中不同细胞的作用,为今后肿瘤的治疗研究寻找一个好的方向。     

p62蛋白功能及相关信号通路研究

p62是一种多功能蛋白,其蛋白分子包含多个结构域,通过与不同蛋白质结合形成细胞中重要的信号中心,从而调控多种信号通路,影响细胞的生长、衰老,甚至死亡等生理过程。p62蛋白通过对mTORC1信号通路的影响在氨基酸信号通路中发挥着关键的调控作用。p62蛋白是自噬体与底物之间的适配蛋白,在细胞自噬过程中起到分子调节器的作用。p62蛋白具有质核穿梭功能,在DNA损伤修复和氧化应激反应中具有重要作用,其异常积累会引起细胞的恶性转变,导致肿瘤的发生。现综述p62在调节多种信号通路,如自噬、氨基酸感知、凋亡及肿瘤发生等过程中的作用。     

前列腺癌雄激素受体和PI3K/Akt信号通路相互作用研究进展

前列腺癌的发生、进展依赖于雄激素,因此去势手术成为治疗晚期前列腺癌的标准疗法。但是去势后大多前列腺癌最终将转化为雄激素非依赖性前列腺癌,甚至进展为激素难治性前列腺癌,使得肿瘤的进展不受低水平雄激素的影响。即使如此,大多数激素非依赖性前列腺癌,依然阳性表达雄激素受体。因而雄激素受体在前列腺癌发生发展中起着重要作用。而PI3K/Akt信号通路能够通过维持细胞生存、抑制细胞凋亡、促进细胞代谢及血管生成等促进前列腺癌进展。本综述旨在总结前人研究,阐述雄激素受体和PI3K/Akt信号通路之间相互作用关系。研究表明Akt信号通路能够正性或者负性调控AR蛋白表达、蛋白的稳定性及其转录活性,从而维持细胞的生存、代谢。而AR即可以通过基因转录途径抑制Akt活化又能通过非转录基因途径激活Akt及其下游蛋白。因此,AR和Akt信号通路相互协同促进前列腺癌的发生及其向雄激素非依赖性前列腺癌进展。     

前列腺癌雄激素受体和PI3K/Akt 信号通路相互作用研究进展

前列腺癌的发生、进展依赖于雄激素,因此去势手术成为治疗晚期前列腺癌的标准疗法。但是去势后大多前列腺癌最终将转化为雄激素非依赖性前列腺癌,甚至进展为激素难治性前列腺癌,使得肿瘤的进展不受低水平雄激素的影响。即使如此,大多数激素非依赖性前列腺癌,依然阳性表达雄激素受体。因而雄激素受体在前列腺癌发生发展中起着重要作用。而PI3K/Akt信号通路能够通过维持细胞生存、抑制细胞凋亡、促进细胞代谢及血管生成等促进前列腺癌进展。本综述旨在总结前人研究,阐述雄激素受体和PI3K/Akt信号通路之间相互作用关系。研究表明Akt信号通路能够正性或者负性调控AR蛋白表达、蛋白的稳定性及其转录活性,从而维持细胞的生存、代谢。而AR即可以通过基因转录途径抑制Akt活化又能通过非转录基因途径激活Akt及其下游蛋白。因此,AR和Akt信号通路相互协同促进前列腺癌的发生及其向雄激素非依赖性前列腺癌进展。     

TGF-β信号通路介导的相关疾病及靶向治疗

TGF-β信号通路是一个由众多细胞因子组成的大家族,调节着包括细胞生长、上皮-间质转化、迁移、分化以及凋亡等在内的许多细胞功能,在组织与器官的正常生长、胚胎发育等过程中起着关键作用.一旦TGF-β信号传导过程发生异常,随之而来的就是一系列发育缺陷和疾病的产生,如肿瘤的发生,组织器官的纤维化,结缔组织以及骨骼疾病等.通过对TGF-β信号通路在不同疾病发生中的作用进行研究,目前已经开发了许多靶向此通路的治疗策略,如单克隆抗体、受体激酶抑制剂和反义寡聚核苷酸等.本综述总结了 TGF-β信号通路在不同疾病发生中的作用,并对最新的靶向此信号通路的治疗策略进行讨论.     

Hippo信号通路生物学作用研究进展

Hippo信号通路是20世纪末在黑腹果蝇中进行基因筛选时发现的,该通路受各种生化、物理和结构信号的影响,调控细胞生长、分化,组织和器官发育以及内环境稳态等基本生物学过程。研究表明Hippo信号通路失调会引起一系列疾病的发生。本文阐述了目前Hippo信号通路在胚胎发育、器官和组织稳态调节、肿瘤的发生发展和细胞自噬等一系列生物学过程以及靶向治疗中的研究进展,其中Hippo信号通路通过细胞自噬来维持机体细胞内环境稳态成为新的研究热点。对该通路的功能和调控机制的深入研究也为组织器官修复再生医学及癌症治疗提供参考。     

肿瘤细胞Hedgehog信号通路及其抑制剂

越来越多的证据显示, 肿瘤的发生、生长、转移、复发以及耐药等均与肿瘤干细胞密切相关.Hedgehog (Hh)信号通路调节胚胎发育和成体许多组织器官干细胞的自我更新与增殖.然而, 那些在正常发育过程中受到Hh信号通路调节的组织器官, 在该信号通路异常时常常发生肿瘤.这些肿瘤包括肝癌、神经胶质瘤、基底细胞癌、横纹肌肉瘤、胰腺癌、小细胞肺癌、胃癌、结肠癌、前列腺癌、黑色素瘤和多发性骨髓瘤等.介绍了近年来Hh信号通路在肿瘤发生和发展过程中的机制、在维持肿瘤干细胞自我更新方面的作用, 以及该通路的特异性抑制剂, 以显示其在肿瘤治疗中潜在的重要意义.最后, 提出了今后肿瘤干细胞Hh通路研究的重点和新思路.     

活性氧介导的信号通路在衣原体感染过程中的作用机制

活性氧(reactive oxygen species,ROS)是一种重要的信号分子,能介导多条信号通路,从而影响宿主细胞的生长与增殖。衣原体为细胞内寄生菌,其感染过程会导致ROS的表达水平增加,ROS可介导多种信号通路,通过氧化修饰蛋白、改变细胞内氧化还原平衡,从而影响衣原体的生长与繁殖。对ROS介导的信号通路在衣原体感染过程中的作用机制作一综述。     

真菌Hog1 MAPK信号通路研究进展

丝裂原活化蛋白激酶(MAPK)信号通路广泛存在于真核细胞并且高度保守,是生物体内非常重要的信号转导系统之一。胞外刺激信号通过细胞膜上的特异性受体传递给胞内MAPK信号通路,该信号通路通过磷酸化下游转录因子、调节各种酶类来调控转录水平及生化反应等,进而使细胞适应外界环境变化。Hog1 MAPK信号通路能够被胞外高渗透压胁迫等刺激激活,对细胞在高渗环境下的存活至关重要。近年来,越来越多的研究发现虽然该信号通路在真核生物中高度保守,但不同物种中的组成仍有差异,且该信号通路的功能也相对多元化。本文综述了Hog1 MAPK信号通路的组成、功能及其与其他信号通路之间的cross-talk,旨在为今后深入研究该信号通路的作用机制及其与其他信号通路间的cross-talk提供参考。     

Prostate cancer bone metastases promote both osteolytic and osteoblastic activity

Advanced prostate cancer is frequently accompanied by the development of metastasis to bone. In the past, prostate cancer bone metastases were characterized as being osteoblastic (i.e., increasing bone density) based on radiographs. However, emerging evidence suggests that development of prostate cancer bone metastases requires osteoclastic activity in addition to osteoblastic activity. The complexities of how prostate tumor cells influence bone remodeling are just beginning to be elucidated. Prostate cancer cells produce a variety of pro-osteoblastic factors that promote bone mineralization. For example, both bone morphogenetic proteins and endothelin-1 have well recognized pro-osteoblastic activities and are produced by prostate cancer cells. In addition to factors that enhance bone mineralization prostate cancer cells produced factors that promote osteoclast activity. Perhaps the most critical pro-osteoclastogenic factor produced by prostate cancer cells is receptor activator of NFkappaB ligand (RANKL), which has been shown to be required for the development of osteoclasts. Blocking RANKL results in inhibiting prostate cancer-induced osteoclastogenesis and inhibits development and progression of prostate tumor growth in bone. These findings suggest that targeting osteoclast activity may be of therapeutic benefit. However, it remains to be defined how prostate cancer cells synchronize the combination of osteoclastic and osteoblastic activity. We propose that as the bone microenvironment is changed by the developing cancer, this in turn influences the prostate cancer cells' balance between pro-osteoclastic and pro-osteoblastic activity. Accordingly, the determination of how the prostate cancer cells and bone microenvironment crosstalk are important to elucidate how prostate cancer cells modulate bone remodeling.     

Bone matrix osteonectin limits prostate cancer cell growth and survival

There is considerable interest in understanding prostate cancer metastasis to bone and the interaction of these cells with the bone microenvironment. Osteonectin/SPARC/BM-40 is a collagen binding matricellular protein that is enriched in bone. Its expression is increased in prostate cancer metastases, and it stimulates the migration of prostate carcinoma cells. However, the presence of osteonectin in cancer cells and the stroma may limit prostate tumor development and progression. To determine how bone matrix osteonectin affects the behavior of prostate cancer cells, we modeled prostate cancer cell-bone interactions using the human prostate cancer cell line PC-3, and mineralized matrices synthesized by wild type and osteonectin-null osteoblasts in vitro. We developed this in vitro system because the structural complexity of collagen matrices in vivo is not mimicked by reconstituted collagen scaffolds or by more complex substrates, like basement membrane extracts. Second harmonic generation imaging demonstrated that the wild type matrices had thick collagen fibers organized into longitudinal bundles, whereas osteonectin-null matrices had thinner fibers in random networks. Importantly, a mouse model of prostate cancer metastases to bone showed a collagen fiber phenotype similar to the wild type matrix synthesized in vitro. When PC-3 cells were grown on the wild type matrices, they displayed decreased cell proliferation, increased cell spreading, and decreased resistance to radiation-induced cell death, compared to cells grown on osteonectin-null matrix. Our data support the idea that osteonectin can suppress prostate cancer pathogenesis, expanding this concept to the microenvironment of skeletal metastases.     

Growth/differentiation factor-15 inhibits differentiation into osteoclasts—A novel factor involved in control of osteoclast differentiation

Survival and capability of cancer cells to form metastases fundamentally depend on interactions with their microenvironment. Secondary tumors originating from prostate carcinomas affect remodeling of bone tissue and can induce both osteolytic and osteocondensing lesions. However, particular molecular mechanisms responsible for selective homing and activity of cancer cells in bone microenvironment have not been clarified yet. Growth/differentiation factor-15 (GDF-15), a distant member of the TGF-β protein family, has recently been associated with many human cancers, including prostate.     

Interleukin‐27 expression modifies prostate cancer cell crosstalk with bone and immune cells in vitro

Prostate cancer is frequently associated with bone metastases, where the crosstalk between tumor cells and key cells of the bone microenvironment (osteoblasts, osteoclasts, immune cells) amplifies tumor growth. We have explored the potential of a novel cytokine, interleukin‐27 (IL‐27), for inhibiting this malignant crosstalk, and have examined the effect of autocrine IL‐27 on prostate cancer cell gene expression, as well as the effect of paracrine IL‐27 on gene expression in bone and T cells. In prostate tumor cells, IL‐27 upregulated genes related to its signaling pathway while downregulating malignancy‐related receptors and cytokine genes involved in gp130 signaling, as well as several protease genes. In both undifferentiated and differentiated osteoblasts, IL‐27 modulated upregulation of genes related to its own signaling pathway as well as pro‐osteogenic genes. In osteoclasts, IL‐27 downregulated several genes typically involved in malignancy and also downregulated osteoclastogenesis‐related genes. Furthermore, an osteogenesis‐focused real‐time PCR array revealed a more extensive profile of pro‐osteogenic gene changes in both osteoblasts and osteoclasts. In T‐lymphocyte cells, IL‐27 upregulated several activation‐related genes and also genes related to the IL‐27 signaling pathway and downregulated several genes that could modulate osteoclastogenesis. Overall, our results suggest that IL‐27 may be able to modify interactions between prostate tumor and bone microenvironment cells and thus could be used as a multifunctional therapeutic for restoring bone homeostasis while treating metastatic prostate tumors. J. Cell. Physiol. © 2012 Wiley Periodicals, Inc.     

A paradigm for the treatment of prostate cancer bone metastases based on an understanding of tumor cell-microenvironment interactions

The pliability of cancer cells to mutate into several different phenotypes in an attempt to find one that will survive and colonize at the metastatic site is a tremendous "hurdle" to overcome in designing novel cancer therapeutics. New targets of therapy are essential if we are to effectively overcome the evasiveness of cancer. The interaction between the tumor cell and the surrounding microenvironment creates a vicious cycle that perpetuates disease survival and progression. The future of cancer therapy resides in the ability to focus on the recruited and exploited relationships of the cancer cell with the host environment. These therapies target cancer cell growth early and interrupt the vicious cycle that is created by the tumor cells interacting with bone components by inhibiting osteoclasts, osteoblasts, stromal cells, and endothelial cells. They alter the bone microenvironment, creating a hostile "soil" that prevents the "seed" from developing into bone metastases and represent a potential new platform for the development of prostate cancer therapeutics.     

Murine mammary tumor cells with a claudin-low genotype

In adults, bone is the preferential target site for metastases from primary cancers of prostate, breast, lungs and thyroid. The tendency of these cancers to metastasize to bone is determined by the anatomical distribution of the blood vessels, by the genetic profile of the cancer cells and by the biological characteristics of the bone microenvironment that favour the growth of metastatic cells of certain cancers. Metastases to bone may have either an osteolytic or an ostoblastic phenotype. The interaction in the bone microenvironment between biological factors secreted by metastatic cells, and by osteoblasts and osteoclasts, and the osteolytic and osteoblastic factors released from the organic matrix mediate a vicious cycle characterized by metastatic growth and by ongoing progressive bone destruction. This interaction determines the phenotype of the metastatic bone disease.     

前列腺癌nm23H1mRNA、TGF-β1mRNA表达及其与肿瘤转移、生存率的相关性研究

应用原位杂交法检测42例前列腺癌组织nm23H1mRNA、TGF-β1mRNA表达,并以CD31抗体为标记,经EnVision~(TM)免疫组织化学及Leica-Qwin计算机图像分析,用Weidner最高血管密度计数法,计数阳性MVD,研究前列腺癌组织nm23H1mRNA、TGF-β1mRNA和CD31的表达与前列腺癌中的新生血管的生成、肿瘤血道转移和调查患者术后的生存率关系。前列腺癌nm23H1mRNA阳性表达66．67%(28例),nm23H1mRNA阳性表达与前列腺癌骨转移、TNM分期、MVD呈负相关(P＜0．05)：TGF-β1mRNA阳性表达78．75%(33例),其与前列腺癌骨转移、TNM分期、MVD呈正相关(P＜0．05),与癌周组织的nm23H1mRNA和TGF-β1mRNA阳性表达比较,具有显著性差异(P＜0．01或P＜0．05)。前列腺癌组织的MVD(78．51±10．29/mm~2)显著高于癌周组织(34．19±9．27/mm~2),两者比较具有显著性差异(P＜0．05)。在根治术后5年内死亡的42．86%(18例)患者中MVD(92．41±15．42/ mm~2),高于5年内生存的患者(62．79±13．58/mm~2),两组间有显著性差异(P＜0．05);在不同的肿瘤病理学分级中,nm23H1mRNA在前列腺癌未、低分化型中阳性表达率高,高、中分化型中阳性表达率低,两组间有显著性差异(P＜0．05)。当nm23H1mRNA阳性表达率高时,肿瘤骨转移率低,生存率高,故认为nm23H1基因具有抑制前列腺癌发生和转移作用。当TGF-β1mRNA阳性表达率高时,肿瘤骨转移率高,生存率低。故认为TGF-β1基因具有促进前列腺癌发生和转移作用。前列腺癌组织中的MVD与肿瘤骨转移密切相关,前列腺癌组织MVD的显著增高,提示肿瘤组织有新血管的生成。TGF-β1促进了肿瘤诱导的血管新生,在前列腺癌的骨转移中起重要作用。     

Bone microenvironment and androgen status modulate subcellular localization of ErbB3 in prostate cancer cells

ErbB-3, an ErbB receptor tyrosine kinase, has been implicated in the pathogenesis of several malignancies, including prostate cancer. We found that ErbB-3 expression was up-regulated in prostate cancer cells within lymph node and bone metastases. Despite being a plasma membrane protein, ErbB-3 was also detected in the nuclei of the prostate cancer cells in the metastatic specimens. Because most metastatic specimens were from men who had undergone androgen ablation, we examined the primary tumors from patients who have undergone hormone deprivation therapy and found that a significant fraction of these specimens showed nuclear localization of ErbB3. We thus assessed the effect of androgens and the bone microenvironment on the nuclear translocation of ErbB-3 by using xenograft tumor models generated from bone-derived prostate cancer cell lines, MDA PCa 2b, and PC-3. In subcutaneous tumors, ErbB-3 was predominantly in the membrane/cytoplasm; however, it was present in the nuclei of the tumor cells in the femur. Castration of mice bearing subcutaneous MDA PCa 2b tumors induced a transient nuclear translocation of ErbB-3, with relocalization to the membrane/cytoplasm upon tumor recurrence. These findings suggest that the bone microenvironment and androgen status influence the subcellular localization of ErbB-3 in prostate cancer cells. We speculate that nuclear localization of ErbB-3 may aid prostate cancer cell survival during androgen ablation and progression of prostate cancer in bone.