Activity of pembrolizumab and lenvatinib in mismatch repair deficient (dMMR) endometrial cancer patients who have failed pembrolizumab monotherapy: A case series.

To evaluate the efficacy of the combination of pembrolizumab and lenvatinib in MMR deficient (dMMR) endometrial cancer (EC) patients who previously failed to respond to single-agent pembrolizumab. A retrospective review of MMR deficient endometrial cancer patients was performed. Patients who failed to respond to pembrolizumab as a single-agent and subsequently received a combination of pembrolizumab and lenvatinib were analyzed. RECIST 1.1 criteria was used to establish clinical response (complete response, partial response, stable disease, and progression) based on CT and/or PET, comparing imaging before and after the addition of lenvatinib. Radiologic review was conducted by an independent radiologist. Eight patients with dMMR EC meeting treatment criteria were identified. The patients' ages ranged from 54 to 80 and all tumors identified were of endometrioid histology. Initial pathologic stage ranged from FIGO stage IB to IVB and recurrence confirmed via imaging or tissue biopsy. Patients received a median of 14 cycles of therapy with pembrolizumab and lenvatinib (range 1-39). All patients had decrease in measurable disease with an objective response of 75 % (PR 62.5 %, CR 12.5 %). Both patients who received the initial recommended dose of 20 mg daily required a dose reduction. Based on this retrospective study, patients with dMMR EC without significant benefit from pembrolizumab monotherapy have a significant clinical response after the addition of lenvatinib. Combination therapy should be considered for dMMR EC patients who fail pembrolizumab monotherapy.

Targeting migration inducting gene-7 inhibits carcinoma cell invasion, early primary tumor growth, and stimulates monocyte oncolytic activity.

Expression of Migration inducting gene-7 (Mig-7) is limited to tumor cells and to date not found in normal tissues. Multiple tumor microenvironment factors, such as epidermal and hepatocyte growth factors, in concert with alphavbeta5 integrin ligation, induce Mig-7 mRNA expression. Gain or loss of Mig-7 protein studies shows that Mig-7 promotes invasion of colon and endometrial carcinoma cells. These data led us to hypothesize that targeting Mig-7 through various methods could decrease invasion, enhance monocyte cell killing of tumor cells, and inhibit disease progression. To begin testing this hypothesis, an in vitro chemoinvasion assay of endometrial carcinoma cells treated with Mig-7-specific or control antibodies was used. Mig-7 antibody significantly reduced invasion by >60% compared with controls. In another approach to test this hypothesis, an in vitro analysis of peptide-stimulated human peripheral blood monocyte cells and their killing of MCF-7 breast carcinoma cells was used. Mig-7 peptide treatment increased monocyte cell tumor necrosis factor expression and killing of MCF-7 cells 30-fold over no peptide stimulation and 3-fold over MUC-1 or control peptide treatments. Furthermore, stably expressing Mig-7-specific short hairpin RNA resulted in significantly reduced Mig-7 protein levels and early primary tumor growth in a xenograft nude mouse model. Reduced phosphorylation of ERK1/2, Akt, and S6 kinase as well as decreased membrane-type 1 matrix metalloproteinase activity were mechanisms through which Mig-7 protein caused these effects. Based on these collective data, Mig-7 expression could be a potential candidate for future targeted cancer therapies.

Translation of an atypical human cDNA requires fidelity of apurine-pyrimidine repeat region and recoding.

Gain or loss of Migration inducting gene-7 (Mig-7) protein expression functional studies suggest it causes aggressive tumor cell invasion and tumor cell vessel-like structure formation. In addition, Mig-7 expression is apparently carcinoma and trophoblast cell-specific. Mig-7 is an example of an atypical gene that is unique in its induction, translation and apparent carcinoma-specific expression. However, studies of this predominantly integral membrane protein are hampered because of the cloning and expression techniques required for detection of Mig-7 protein. Because the encoding region possesses stop codons, repeat sequences and secondary structure, we hypothesized that genetically engineered E. coli are required to maintain the number of purine-pyrimidine repeats and reading frame when producing expression plasmids containing the Mig-7 sequence. Cloning Mig-7 sequence using E. coli genetically engineered to lack recombination and rearrangement capabilities prevented extension of the repeat region. Because of multiple stop codons in the sequence, three different constructs starting from three different reading frame ATG sites were tested for protein production in a human carcinoma cell line. Mig-7 protein of ~23 kD is produced from Mig-7 cDNA that contains multiple stop codons downstream from the ATG in a Kozak consensus sequence. In silico analyses imply that multiple Mig-7 mRNA secondary structures may cause frameshifting, read-through, and/or recoding of the multiple stop codons. Experimental results support that one or more of these translational events take place. In this report, we detail requirements for cloning and expression of this novel, atypical, human gene. These techniques can be used to express this unique protein for further studies.

Overexpression of carcinoma and embryonic cytotrophoblast cell-specific Mig-7 induces invasion and vessel-like structure formation.

Molecular requirements for carcinoma cell interactions with the microenvironment are critical for disease progression but are poorly understood. Integrin alpha v beta 5, which senses the extracellular matrix, is important for carcinoma cell dissemination in vivo. alpha v beta 5 signaling induces Mig-7, a novel human gene product that is apparently carcinoma-specific. We hypothesized that Mig-7 expression facilitates tumor cell dissemination by increasing invasion and vasculogenic mimicry. Results show that embryonic cytotrophoblasts up-regulated Mig-7 expression before they acquired an invasive phenotype capable of pseudovasculogenesis. Mig-7 protein primarily co-localized with vasculogenic mimicry markers factor VIII-associated antigen, vascular endothelial-cadherin, and laminin 5 gamma 2 chain domain III fragment in lymph node metastases. Overexpression of Mig-7 increased gamma 2 chain domain III fragments known to contain epidermal growth factor (EGF)-like repeats that can activate EGF receptor. Interestingly, EGF also induced Mig-7 expression. Carcinoma cell adhesion to laminins was significantly reduced by Mig-7 expression. Remarkably, in two-dimensional and three-dimensional Matrigel cultures, Mig-7 expression caused invasion and vessel-like structures. Melanoma cells, which were previously characterized to invade aggressively and to undergo vasculogenic mimicry, expressed Mig-7. Taken together, these data suggest that Mig-7 expression allows cells to sense their environment, to invade, and to form vessel-like structures through a novel relationship with laminin 5 gamma 2 chain domain III fragments.