Signal transducer and activator of transcription 3 (STAT3) is a latent cytoplasmic transcription factor, originally discovered as a transducer of signal from cell surface receptors to the nucleus. It is activated by tyrosine phosphorylation at position 705 leading to its dimerization, nuclear translocation, DNA binding, and activation of gene transcription. Under normal physiological conditions, STAT3 activation is tightly regulated. However, compelling evidence suggests that STAT3 is constitutively activated in many cancers and plays a pivotal role in tumor growth and metastasis. It regulates cellular proliferation, invasion, migration, and angiogenesis that are critical for cancer metastasis. In this paper, we first describe the mechanism of STAT3 regulation followed by how STAT3 is involved in cancer metastasis, then we summarize the various small molecule inhibitors that inhibit STAT3 signaling.

Colorectal cancer (CRC) is a common cancer worldwide with a low reported incidence in India. There is significant geographical variation in the incidence rates, and the presentation may also vary. There are few studies evaluating the clinical profile of CRC in Indian patients. We analyzed a prospective database maintained at the Tata Memorial Hospital, a referral cancer center in Mumbai, of consecutive patients with CRC between August 2013 and August 2014. We captured details regarding the demography, symptoms, pathology, stage, and treatment plan. The aim was to assess the demographic and clinical details of patients with CRC in India and compare it with those of the reported literature. Eight hundred new patients with CRC were seen in the colorectal clinic in one year. The mean age was 47.2 years. Sixty-five percent were males. Patients were symptomatic for an average period of 4 months prior to presentation. The commonest symptoms were rectal bleeding (57%), pain (44%), and altered bowel habits (26%). Thirteen percent of the patients had signet ring tumors. The median CEA (carcinoembryonic antigen) level was 5.8 ng/mL. Most patients had localized or locally advanced disease. Twenty-eight percent of the patients had metastatic disease with liver being the commonest site of metastases (14%) followed by peritoneum and lung. More than half of the patients received treatment with a curative intent. Colorectal cancer in India differs from that described in the Western countries. We had more young patients, higher proportion of signet ring carcinomas, and more patients presenting with an advanced stage. Inadequate access to healthcare and socioeconomic factors may play a role in some of these differences.

The chromatin organizer SATB1 has been implicated in the development and progression of multiple cancers including breast and colorectal cancers. However, the regulation and role of SATB1 in colorectal cancers is poorly understood. Here, we demonstrate that expression of SATB1 is induced upon hyperactivation of Wnt/β-catenin signaling and repressed upon depletion of TCF7L2 (TCF4) and β-catenin. Using several colorectal cancer cell line models and the APC min mutant zebrafish in vivo model, we established that SATB1 is a novel target of Wnt/β-catenin signaling. We show that direct binding of TCF7L2/β-catenin complex on Satb1 promoter is required for the regulation of SATB1. Moreover, SATB1 is sufficient to regulate the expression of β-catenin, members of TCF family, multiple downstream effectors and mediators of Wnt pathway. SATB1 potentiates the cellular changes and expression of key cancer-associated genes in non-aggressive colorectal cells, promotes their aggressive phenotype and tumorigenesis in vivo. Conversely, depletion of SATB1 from aggressive cells reprograms the expression of cancer-associated genes, reverses their cancer phenotype and reduces the potential of these cells to develop tumors in vivo. We also show that SATB1 and β-catenin bind to the promoters of TCF7L2 and the downstream targets of Wnt signaling and regulate their expression. Our findings suggest that SATB1 shares a feedback regulatory network with TCF7L2/β-catenin signaling and is required for Wnt signaling-dependent regulation of β-catenin. Collectively, these results provide unequivocal evidence to establish that SATB1 reprograms the expression of tumor growth- and metastasis-associated genes to promote tumorigenesis and functionally overlaps with Wnt signaling critical for colorectal cancer tumorigenesis.

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Locally advanced unresectable cancers may benefit from neoadjuvant chemoradiation to facilitate a curative resection with a good survival.

There are little data on the efficacy and safety of taxane/platinum with definitive radiotherapy (RT) for esophageal/GEJ cancer. This article is a retrospective analysis of patients who received weekly paclitaxel 50 mg/m(2) and carboplatin AUC 2 with radical definitive RT for locally advanced esophageal/GEJ cancer. Between February 2011 and July 2014, 179 patients were included. The median age was 54 years. Ninety-two percent of patients had squamous histology. Mean RT dose was 58.7 Gy in 32 fractions over 53 days, with mean of six chemotherapy cycles. Fifty-six percent of patients developed ≥grade 3 acute toxicities, commonly febrile neutropenia (12%) and infection (11%); ≥grade 3 laboratory abnormalities included hyponatremia (38%), leukopenia (49%), neutropenia (27%), and anemia (16%). Twelve percent of patients developed ≥grade 3 chronic toxicity. Fatal toxicities included six during CRT, eight within 30 days of completing CRT, and three chronic. Radiologic response was 49% (CR 5.6%, PR 43%). Follow-up endoscopy showed remission in 53% and residual disease in 14%. At a median follow-up of 28 months, median PFS was 11 months (95% CI: 8-13.9), median OS was 19 months (95% CI: 15.4-22.6), and estimated 1-year, 2-year, and 3-year survivals were 70%, 47%, and 39%, respectively. Weekly paclitaxel-carboplatin concurrently with definitive RT is efficacious with manageable toxicity. [The trial was registered with the Clinical Trials Registry-India (CTRI), registration number: CTRI/2014/07/004776.].

Escalated radiation dose without chemotherapy does not achieve higher complete (R0) tumor resectability in locally advanced inoperable rectal cancers, compared to concurrent chemoradiation.