Site-Specific Dinitrophenylation of Single-Chain Antibody Fragments for Redirecting a Universal CAR-T Cell against Cancer Antigens

We have previously developed a universal chimeric antigen receptor (CAR), which recognizes dinitrophenyl (DNP) and can redirect T and NK cells to target cancer and HIV antigens using DNP-conjugated antibodies as adaptor molecules. However, the DNP-antibody conjugates are generated by random modification, which may not be optimal for this modular system. Here, we report the development of enhanced adaptor molecules by site-specific DNP modification. We use the genetic code expansion technology to generate single-chain fragment variable (scFv) antibodies with site-specific DNP. We compare four anti-CD19 scFv mutants and find that the one with DNP at the flexible peptide linker between V_H and V_L is the most effective in redirecting anti-DNP CAR-T cells against CD19+ cells. The other three mutants are ineffective in doing so due to reduced DNP exposure or abrogated CD19 binding. We also use the anti-CD22 scFv as another model adaptor molecule and again find that the peptide linker is ideal for DNP derivatization. Our approach can potentially be used to design enhanced adaptor molecules to redirect the DNP-mediated universal CAR against other tumor antigens.

A Universal CAR-NK Cell Targeting Various Epitopes of HIV-1 gp160

Engineering T cells and natural killer (NK) cells with anti-HIV chimeric antigen receptors (CAR) has emerged as a promising strategy to eradicate HIV-infected cells. However, current anti-HIV CARs are limited by targeting a single epitope of the HIV envelope glycoprotein gp160, which cannot counter the enormous diversity and mutability of viruses. Here, we report the development of a universal CAR-NK cell, which recognizes 2,4-dinitrophenyl (DNP) and can subsequently be redirected to target various epitopes of gp160 using DNP-conjugated antibodies as adaptor molecules. We show that this CAR-NK cell can recognize and kill mimic HIV-infected cell lines expressing subtypes B and C gp160. We additionally find that anti-gp160 antibodies targeting membrane-distal epitopes (including V1/V2, V3, and CD4bs) are more likely to activate universal CAR-NK cells against gp160⁺ target cells, compared with those targeting membrane-proximal epitopes located in the gp41 MPER. Finally, we confirm that HIV-infected primary human CD4⁺ T cells can be effectively killed using the same approach. Given that numerous anti-gp160 antibodies with different antigen specificities are readily available, this modular universal CAR-NK cell platform can potentially overcome HIV diversity, thus providing a promising strategy to eradicate HIV-infected cells.

Dicer ablation promotes a mesenchymal and invasive phenotype in bladder cancer cells

Dicer expression is frequently altered in cancer and affects a wide array of cellular functions acting as an oncogene or tumor suppressor in varying contexts. It has been shown that Dicer expression is also deregulated in urothelial cell carcinoma of the bladder (UCCB) but the nature of this deregulation differs between reports. The aim of the present study was to gain a better understanding of the role of Dicer in bladder cancer to help determine its contribution to the disease. The results showed that Dicer transcript levels were decreased in UCCB tumor tissues as compared to normal tissues, suggesting that Dicer is a tumor suppressor. However, consistent with previous results, we demonstrated that knockdown of Dicer decreases cell viability and increases the induction of apoptosis, suggesting that Dicer is an oncogene. To resolve this discrepancy, we assessed the effects of decreased Dicer expression on epithelial-to‑mesenchymal transition, migration and invasion. We showed that decreased Dicer levels promoted a mesenchymal phenotype and increased migration. Additionally, the results showed that Dicer protein ablation leads to increased cell invasion, higher levels of matrix metalloproteinase-2, and decreased levels of key miRNAs shown to inhibit invasion. The results of this study suggest that decreased Dicer levels may portend a more malignant phenotype.

miR-148a dependent apoptosis of bladder cancer cells is mediated in part by the epigenetic modifier DNMT1

Urothelial cell carcinoma of the bladder (UCCB) is the most common form of bladder cancer and it is estimated that ~15,000 people in the United States succumbed to this disease in 2013. Bladder cancer treatment options are limited and research to understand the molecular mechanisms of this disease is needed to design novel therapeutic strategies. Recent studies have shown that microRNAs play pivotal roles in the progression of cancer. miR-148a has been shown to serve as a tumor suppressor in cancers of the prostate, colon, and liver, but its role in bladder cancer has never been elucidated. Here we show that miR-148a is down-regulated in UCCB cell lines. We demonstrate that overexpression of miR-148a leads to reduced cell viability through an increase in apoptosis rather than an inhibition of proliferation. We additionally show that miR-148a exerts this effect partially by attenuating expression of DNA methyltransferase 1 (DNMT1). Finally, our studies demonstrate that treating cells with both miR-148a and either cisplatin or doxorubicin is either additive or synergistic in causing apoptosis. These data taken together suggest that miR-148a is a tumor suppressor in UCCB and could potentially serve as a novel therapeutic for this malignancy.

Thermal burns in diabetic feet

Many patients with diabetes can lead a full life without developing diabetic lesions in their feet. This is because these patients have avoided the precipitating factors of which the most important is mechanical trauma and infections. We present five cases of diabetic patients who, out of ignorance, listened to bad advice by using hot therapy to treat their peripheral neuropathy. This resulted in burns and secondary infections. All of them required large surgical debridement and prolonged costly hospital stay to treat their condition. Fortunately, none of them required amputation. This paper hopes to highlight the dangers of self treatment and medication in diabetic foot lesions.