Polyclonal rabbit anti-human ovarian cancer globulins inhibit tumor growth through apoptosis involving the caspase signaling

Enhanced in vivo anti-tumor efficacy of whole tumor lysate in combination with whole tumor cell-specific polyclonal antibody

Background and purpose

Despite the widespread utilization of cancer vaccines with specified antigens, the use of whole tumor cell lysates in tumor immunotherapy would be a very promising approach that can overcome several significant obstacles in vaccine production. Whole tumor cells provide a broad source of tumor-associated antigens and can activate cytotoxic T lymphocytes and CD4+ T helper cells concurrently. On the other hand, as an effective immunotherapy strategy, recent investigations have shown that the multi-targeting of tumor cells with polyclonal antibodies, which are also more effective than monoclonal antibodies at mediating effector functions for target elimination, might minimize the escape variants.

Experimental approach

We prepared polyclonal antibodies by immunizing rabbits with the highly invasive 4T1 breast cancer cell line.

Findings/Results

In vitro investigation indicated that the immunized rabbit serum inhibited cell proliferation and induced apoptosis in target tumor cells. Moreover, in vivo analysis showed enhanced anti-tumor efficacy of whole tumor cell lysate in combination with tumor cell-immunized serum. This combination therapy proved beneficial in significant inhibition of the tumor growth and the established tumor was entirely eradicated in treated mice.

Conclusion and implications

Serial intravenous injections of tumor cell immunized rabbit serum significantly inhibited tumor cell proliferation and induced apoptosis in vitro and in vivo in combination with whole tumor lysate. This platform could be a promising method for developing clinical-grade vaccines and open up the possibility of addressing the effectiveness and safety of cancer vaccines.

Polyclonal Rabbit Anti-Cancer-Associated Fibroblasts Globulins Induce Cancer Cells Apoptosis and Inhibit Tumor Growth

Cancer-associated fibroblasts (CAFs) constitute a major component of the tumor microenvironment. CAFs regulated the growth and development, invasion and metastasis of primary tumors, as well as response to treatment. Recent studies indicated that monoclonal antibody therapies had limited success, thus more effective polyclonal antibodies (Poly Abs) is urgently needed. Poly Abs is a possible alternative because they target multiple antigens simultaneously. In this report, we prepared Poly Abs by immunizing rabbits with the bFGF-activated fibroblasts. The Poly Abs inhibited the cancer cells proliferation as revealed by MTT analysis. The Poly Abs induced apoptosis as indicated by flow cytometric analysis, and microscopic observation of apoptotic changes in morphology. Compared with the control IgG, Poly Abs significantly inhibited tumor cells migration as indicated by wound healing and transwell analysis in vitro, and lung metastasis analysis in vivo. Serial intravenous injections of Poly Abs inhibited tumor growth in mice bearing murine CT26 colon carcinoma. Ki67 analysis indicated that Poly Abs significantly inhibited tumor cells proliferation, as compared to control Ig G treatments. Our findings suggested that Poly Abs was an effective agent for apoptosis induction, migration and metastasis inhibition. The Poly Abs may be useful as a safe anticancer agent for cancer immunotherapy in the future.

Technological advances in precision medicine and drug development

New technologies are rapidly becoming available to expand the arsenal of tools accessible for precision medicine and to support the development of new therapeutics. Advances in liquid biopsies, which analyze cells, DNA, RNA, proteins, or vesicles isolated from the blood, have gained particular interest for their uses in acquiring information reflecting the biology of tumors and metastatic tissues. Through advancements in DNA sequencing that have merged unprecedented accuracy with affordable cost, personalized treatments based on genetic variations are becoming a real possibility. Extraordinary progress has been achieved in the development of biological therapies aimed to even further advance personalized treatments. We provide a summary of current and future applications of blood based liquid biopsies and how new technologies are utilized for the development of biological therapeutic treatments. We discuss current and future sequencing methods with an emphasis on how technological advances will support the progress in the field of precision medicine.

Immunotherapeutic approaches to ovarian cancer treatment

Despite advances in combinatorial chemotherapy regimens and the advent of intraperitoneal chemotherapy administration, current therapeutic options for ovarian cancer patients are inadequate. Immunotherapy offers a novel and promising therapeutic strategy for treating ovarian tumors. Following the demonstration of the immunogenicity of ovarian tumors, multiple immunotherapeutic modalities have been developed. Antibody-based therapies, immune checkpoint blockade, cancer vaccines, and chimeric antigen receptor-modified T cells have demonstrated preclinical success and entered clinical testing. In this review, we discuss these promising immunotherapeutic approaches and emphasize the importance of combinatorial treatment strategies and biomarker discovery.

MDR1 siRNA loaded hyaluronic acid-based CD44 targeted nanoparticle systems circumvent paclitaxel resistance in ovarian cancer

Development of multidrug resistance (MDR) is an almost universal phenomenon in patients with ovarian cancer, and this severely limits the ultimate success of chemotherapy in the clinic. Overexpression of the MDR1 gene and corresponding P-glycoprotein (Pgp) is one of the best known MDR mechanisms. MDR1 siRNA based strategies were proposed to circumvent MDR, however, systemic, safe, and effective targeted delivery is still a major challenge. Cluster of differentiation 44 (CD44) targeted hyaluronic acid (HA) based nanoparticle has been shown to successfully deliver chemotherapy agents or siRNAs into tumor cells. The goal of this study is to evaluate the ability of HA-PEI/HA-PEG to deliver MDR1 siRNA and the efficacy of the combination of HA-PEI/HA-PEG/MDR1 siRNA with paclitaxel to suppress growth of ovarian cancer. We observed that HA-PEI/HA-PEG nanoparticles can efficiently deliver MDR1 siRNA into MDR ovarian cancer cells, resulting in down-regulation of MDR1 and Pgp expression. Administration of HA-PEI/HA-PEG/MDR1 siRNA nanoparticles followed by paclitaxel treatment induced a significant inhibitory effect on the tumor growth, decreased Pgp expression and increased apoptosis in MDR ovarian cancer mice model. Our findings suggest that CD44 targeted HA-PEI/HA-PEG/MDR1 siRNA nanoparticles can serve as a therapeutic tool with great potentials to circumvent MDR in ovarian cancer.