Heterogeneity and interplay: the multifaceted role of cancer-associated fibroblasts in the tumor and therapeutic strategies.

The journey of cancer development is a multifaceted and staged process. The array of treatments available for cancer varies significantly, dictated by the disease's type and stage. Cancer-associated fibroblasts (CAFs), prevalent across various cancer types and stages, play a pivotal role in tumor genesis, progression, metastasis, and drug resistance. The strategy of concurrently targeting cancer cells and CAFs holds great promise in cancer therapy. In this review, we focus intently on CAFs, delving into their critical role in cancer's progression. We begin by exploring the origins, classification, and surface markers of CAFs. Following this, we emphasize the key cytokines and signaling pathways involved in the interplay between cancer cells and CAFs and their influence on the tumor immune microenvironment. Additionally, we examine current therapeutic approaches targeting CAFs. This article underscores the multifarious roles of CAFs within the tumor microenvironment and their potential applications in cancer treatment, highlighting their importance as key targets in overcoming drug resistance and enhancing the efficacy of tumor therapies.

Platelets for cancer treatment and drug delivery.

Extensive research is currently being conducted into a variety of bio-inspired biomimetic nanoparticles (NPs) with new cell simulation functions across the fields of materials science, chemistry, biology, physics, and engineering. Cells such as erythrocytes, platelets, and stem cells have been engineered as new drug carriers. The platelet-derived drug delivery system, which is a new targeted drug delivery system (TDDS), can effectively navigate the blood circulatory system and interact with the complex tumor microenvironment; it appears to outperform traditional anticancer drugs; hence, it has attracted considerable research interest. In this review, we describe innovative studies and outline the latest progress regarding the use of platelets as tumor targeting and drug delivery vehicles; we also highlight opportunities and challenges relevant to the manufacture of tumor-related platelet TDDSs.

Screening and antitumor effect of an anti­CTLA­4 nanobody.

Cytotoxic T­lymphocyte antigen­4 (CTLA­4) is a critical negative regulator of immune responses. CTLA­4 is rapidly upregulated following T­cell activation, and then binds to B7 molecules with a higher affinity than CD28. CTLA­4 may abolish the initiation of the responses of T cells by raising the threshold of signals required for full activation of T cells, and it also may terminate ongoing T-cell responses. This regulatory role has led to the development of monoclonal antibodies (mAbs) designed to block CTLA­4 activity for enhancing immune responses against cancer. mAbs have several disadvantages including high production cost and unstable behavior. Nanobodies (Nbs) are single­domain antigen­binding fragments derived from the camelid heavy­chain antibodies, which are highly attractive in cancer immunotherapy due to their small size, high specificity, and stability. We selected CTLA­4­specific Nbs from a high quality dromedary camel immune library by phage display technology. Four positive colonies were sequenced and classified based on the amino acids sequences in the CDR3 region. These Nbs recognized unique epitopes on CTLA­4 and displayed high binding rates when used on PHA­stimulated human T cells. Treatment of B16 melanoma­bearing C57BL/6 mice with anti­CTLA­4 nanobody 16 (Nb16) delayed melanoma growth and prolonged the survival time of mice. These data indicate that anti­CTLA­4 Nbs selected from a high quality phage display library may be effective for the treatment of patients with tumors.

Quantum dot/pMHC multimers vs. phycoerythrin/pMHC tetramers for identification of HLA-A*0201-restricted pHBV core antigen18-27-specific T cells.

Detection of human leukocyte antigens-A2-restricted p-hepatitis B virus (HBV) core antigen­specific cytotoxic T lymphocytes (CTLs) is important in the study of HBV immunopathogenesis and vaccine design. Currently, major histocompatibility complex (MHC) class I/peptide­(p) MHCI tetramers are considered the optimal tools to detect antigen­specific CTLs. However, the MHC­tetramer technique also has certain drawbacks and is under continuous development. The quantum dot (QD) bioconjugates nanotechnology with its unique inorganic­biological properties has been developing fast. However, QD/pMHC multimers have seldom been used for the identification of the C18­27 epitope, which is important in HBV infection. QD/pMHC multimers were synthesized by metal­affinity coordination and an avidin­biotin system. In the present study they were characterized by transmission electron microscopy, dynamic light scattering and fluorescence spectrophotometry. C18­27­specific CTLs were obtained by ex vivo expansion of CD8+ T cells. Cultured CTLs were tested for the secretion level of interferon (IFN)­Î³ by ELISA and for cytotoxicity by lactate dehydrogenase release assay. Then, the performance of phycoerythrin (PE)/pMHC tetramers and QD/pMHC multimers were compared by flow cytometry. The synthesized QD/pMHC multimers dispersed well and their emission spectrum exhibited only slight differences compared with original QDs. C18­27­specific CTLs not only secreted IFN­Î³ but also effectively targeted T2 cells pulsed with peptide C18­27. The frequencies of C18­27­specific CTLs determined by QD/pMHC multimers were higher compared with PE/pMHC tetramers. The present results suggested that QD/pMHC multimers may be able to characterize greater numbers of C18­27­specific CTLs with increased sensitivity compared to conventional strategies.

An 'activatable' aptamer-based fluorescence probe for the detection of HepG2 cells.

It is significant to develop a probe with sensitivity and specificity for the detection of cancer cells. The present study aimed to develop an 'activatable' aptamer-based fluorescence probe (AAFP) to detect cancer cells and frozen cancer tissue. This AAFP consisted of two fragments: aptamer TLS11a that targets HepG2 cells, and two short extending complementary DNA sequences with a 5'- and 3'-terminus that make the aptamer in hairpin structure a capable quencher to fluorophore. The ability of the AAFP to bind specifically to cancer cells was assessed using flow cytometry, fluorescence spectroscopy and fluorescence microscopy. Its ability to bind to frozen cancer tissue was assessed using fluorescence microscopy. As a result, in the absence of cancer cells, AAFP showed minimal fluorescence, reflecting auto-quenching. In the presence of cancer cells, however, AAFP showed a strong fluorescent signal. Therefore, this AAFP may be a promising tool for sensitive and specific detection of cancer.

Enhanced anti-tumor immunity against breast cancer induced by whole tumor cell vaccines genetically modified expressing α-Gal epitopes.

Whole tumor cell vaccines have shown much promise, but demonstrated poor efficiency in phase III trials. In this study, we modified MDA-MB­231 tumor cells (MDA-MB­231Gal+) to express α-1, 3-galactosyltransferase (α-1, 3-GT) protein, to potentially enhance antitumor effect of whole tumor cell vaccines. MDA-MB­231 tumor cell vaccines were transfected with a reconstructed lentiviral containing α-1, 3-GT genes. Tumor growth, tumorigenesis and survival of Hu-NOD-SCID mice were observed when tumor-bearing mice were injected with tumor cell vaccines. Proliferation and apoptosis in MDA-MB­231 tumor xenografts were observed by immunohistochemistry. The levels of cytokine secretion in the serum of mice were tested by ELISA. CD8+ T cells infiltrating tumors were assessed by flow cytometry. MDA-MB­231Gal+ cells expressed active α-1, 3-GT and produced α-Gal in vitro. MDA-MB­231Gal+ cell vaccines suppressed tumor growth and tumorigenesis in immunized Hu-NOD-SCID mice. Additionally, decrease of TGF-ß, IL-10 and increase of INF-γ, IL-12 were observed in tumor cell vaccinated mice. Furthermore, the cell vaccines enhanced infiltration of cytotoxic CD8+ T cells in the tumor microenvironment of immunized mice. The MDA-MB­231Gal+ cell vaccines modified α-1, 3-GT genes improved the antitumor effect.

Highly sensitive detection of leukemia cells based on aptamer and quantum dots.

Detection of leukemia at the early stage with high sensitivity is a significant clinical challenge for clinicians. In the present study, we developed a sensitive detector consisting of the product of oligonucleotides hybridized with semiconductor quantum dots (QDs) to generate a stronger fluorescent signal so that leukemic cells can be captured. In the present study, a biotin-modified Sgc8 aptamer was used to identify CCRF-CEM cells, and then biotin-appended QDs were labeled with the aptamer via streptavidin and biotin amplification interactions. We described the complex as QDs-bsb-apt. CEM and Ramos cells were used to assess the specificity and sensitivity of the novel complex. These results revealed that the complex could be more effective in diagnosing leukemia at the early stage. In conclusion, an innovative structure based on aptamer and QDs for leukemia diagnosis was provided. It has the potential to image tumor cells in vitro or in vivo and to realize the early diagnosis of disease. Furthermore, it may be used to provide guidance for clinicians to implement individualized patient therapy.

A novel method for endothelial cell isolation.

The present study aimed to develop a quick and efficient method for purification of newborn endothelial cells from tumor tissues. Fresh tissues were separated from C57BL/6 mice bearing tumors derived from mouse lung cancer Lewis cells, fully minced and divided into two parts. One part was subjected to collagenase type I digestion with a vortex to form a single-cell suspension, while another part was digested but without a vortex. Then, the CD105+ cells were isolated using anti-CD105 antibody-coated Dynabeads. The isolated CD105+ cells were grown in culture medium and examined for the surface expression of CD105 by a fluorescence-activated cell sorter (FACS). The uptake of acetylated LDL and the ability to maintain capillary tube-like structure formation in the CD105+ cells were also examined by Dil-Ac-LDL uptake assay and tube formation assay. The expression of tumor newborn endothelial cells (CD105+) was tested in Lewis xenografts by immunohistochemistry. The number of cells which were obtained by the digestion process with a vortex was 5.70±0.23x10(4) much higher than the number without a vortex (0.32±0.04x10(4)) (P<0.01). The purity of CD105+ cell digestion with a vortex was significantly higher than that without a vortex. Dil-Ac-LDL uptake assay and tube formation assay confirmed that the CD105+ cells digested with a vortex exhibited typical functions of endothelial cells. In conclusion, the CD105+ cells isolated by the new method had high purity and displayed features of vascular endothelial cells. The modified method provides CD105+ cells with superior conditions for mechanistic research on the development of vessel-based disease.