RRx-001 Priming of PD-1 Inhibition in the Treatment of Small Cell Carcinoma of the Vagina: A Rare Gynecological Tumor.

Small cell carcinoma of the vagina is rare, so rare in fact that the total number reported in English-language journals is less than 30. Due to this extremely low incidence, no specific treatment guidelines have been established, and most of what is clinically known is derived from a handful of single case reports. However, as befitting its highly aggressive histologic features, which are reminiscent of small cell lung cancer (SCLC), first-line treatment is modeled after SCLC. Herein is reported the case of a 51-year-old African-American patient with metastatic biopsy-proven small cell carcinoma of the vagina that progressed through multiple therapies: first-line cisplatin and etoposide (making it platinum-resistant) and radiotherapy, followed by the tumor macrophage-stimulating agent RRx-001 in a clinical trial called QUADRUPLE THREAT, which per protocol preceded a mandated rechallenge with cisplatin and etoposide. RECIST v.1.1 tumor progression on both RRx-001 and cisplatin/etoposide was accompanied by central necrosis in several of the enlarged lymph nodes and hepatic metastases, which may have been evidence of pseudoprogression, accounting for her ongoing longer-than-expected survival, since the necrotic tissue may have primed the activity of the PD-1 inhibitor. The lack of response to RRx-001 is hypothesized to have correlated with sparse tumor macrophage infiltration, seen on pre- and post-treatment biopsies, since the mechanism of action of RRx-001 relates to stimulation of tumor-associated macrophages.

Visualizing the phage T4 activated transcription complex of DNA and E. coli RNA polymerase.

The ability of RNA polymerase (RNAP) to select the right promoter sequence at the right time is fundamental to the control of gene expression in all organisms. However, there is only one crystallized structure of a complete activator/RNAP/DNA complex. In a process called σ appropriation, bacteriophage T4 activates a class of phage promoters using an activator (MotA) and a co-activator (AsiA), which function through interactions with the σ(70) subunit of RNAP. We have developed a holistic, structure-based model for σ appropriation using multiple experimentally determined 3D structures (Escherichia coli RNAP, the Thermus aquaticus RNAP/DNA complex, AsiA /σ(70) Region 4, the N-terminal domain of MotA [MotA(NTD)], and the C-terminal domain of MotA [MotA(CTD)]), molecular modeling, and extensive biochemical observations indicating the position of the proteins relative to each other and to the DNA. Our results visualize how AsiA/MotA redirects σ, and therefore RNAP activity, to T4 promoter DNA, and demonstrate at a molecular level how the tactful interaction of transcriptional factors with even small segments of RNAP can alter promoter specificity. Furthermore, our model provides a rational basis for understanding how a mutation within the ß subunit of RNAP (G1249D), which is far removed from AsiA or MotA, impairs σ appropriation.

A second-generation 2-Methoxyestradiol prodrug is effective against Barrett's adenocarcinoma in a mouse xenograft model.

2-Methoxyestradiol (2-ME2) is an endogenous metabolite of estradiol. In preclinical models, 2-ME2 is effective against different types of tumors. Unfortunately, only low systemic concentrations of 2-ME2 can be achieved following oral administration, even after very high doses are administered to patients. In an effort to solve this problem, we have now synthesized and tested a new prodrug of 2-ME2 that is water-soluble due to a bioreversible hydrophilic group added at the 3-position and that more effectively resists metabolic inactivation due to an ester moiety added to mask the 17-position alcohol. We are reporting here for the first time that this double prodrug of 2-ME2 is effective as an antiproliferative and anticancer agent for both in vitro and in vivo studies against Barrett esophageal adenocarcinoma (BEAC) and provided greater potency than 2-ME2 in inhibiting the growth of BEAC xenografts. Finally, studies indicate that, like 2-ME2, the 2-ME2-PD1 exhibits anticancer effect through possible disruption of microtubule network.

Cloning and characterization of cDNAs encoding for long-chain saturated acyl-ACP thioesterases from the developing seeds of Brassica juncea.

Four types of cDNAs corresponding to the fatty acyl-acyl carrier protein (ACP) thioesterase (Fat) enzyme were isolated from the developing seeds of Brassica juncea, a widely cultivated species amongst the oil-seed crops. The mature polypeptides deduced from the cDNAs showed sequence identity with the FatB class of plant thioesterases. Southern hybridization revealed the presence of at least four copies of BjFatB gene in the genome of this amphidiploid species. Western blot and RT-PCR analyses showed that the BjFatB class thioesterase is expressed poorly in flowers and leaves, but significantly in seeds at the mid-maturation stage. The enzymatic activities of different BjFatB isoforms were established upon heterologous expression of the four BjFatB CDSs in Escherichia coli K27fadD88, a mutant strain of fatty acid beta-oxidation pathway. The substrate specificity of each BjFatB isoform was determined in vivo by fatty acid profile analyses of the culture supernatant and membrane lipid of the recombinant K27fadD88 and E. coli DH10B (fadD(+)) clones, respectively. The BjFatB1 and BjFatB3 were predominantly active on C18:0-ACP substrate, whereas BjFatB2 and BjFatB4 were specific towards C18:0-ACP as well as C16:0-ACP. These novel FatB genes may find potential application in metabolic engineering of crop plants through their over-expression in seed tissues to generate stearate-rich vegetable fats/oils of commercial importance.